diff --git a/app/build.gradle.kts b/app/build.gradle.kts
index 9ccbfc2..0ba8b70 100644
--- a/app/build.gradle.kts
+++ b/app/build.gradle.kts
@@ -54,6 +54,7 @@ android {
     }
     buildFeatures {
         compose = true
+        buildConfig = true
     }
 }
 
@@ -78,6 +79,12 @@ dependencies {
     implementation(libs.retrofit)
     implementation(libs.converter.gson)
 
+    // OKHttp
+    implementation(libs.logging.interceptor)
+
+    // DataStore
+    implementation(libs.androidx.datastore.preferences)
+
     implementation(libs.androidx.core.splashscreen)
     implementation(libs.androidx.material)
     implementation(libs.androidx.material.icons.core)
diff --git a/app/src/main/java/com/sampoom/android/app/navigation/AppNavHost.kt b/app/src/main/java/com/sampoom/android/app/navigation/AppNavHost.kt
index 3368d4b..d167d4b 100644
--- a/app/src/main/java/com/sampoom/android/app/navigation/AppNavHost.kt
+++ b/app/src/main/java/com/sampoom/android/app/navigation/AppNavHost.kt
@@ -19,9 +19,11 @@ import androidx.navigation.compose.currentBackStackEntryAsState
 import androidx.navigation.compose.rememberNavController
 import com.sampoom.android.R
 import com.sampoom.android.feature.auth.ui.LoginScreen
+import com.sampoom.android.feature.auth.ui.SignUpScreen
 import com.sampoom.android.feature.part.ui.PartScreen
 
 const val ROUTE_LOGIN = "login"
+const val ROUTE_SIGNUP = "signup"
 const val ROUTE_HOME = "home"
 
 // Main Screen
@@ -51,7 +53,7 @@ fun AppNavHost() {
     val navController = rememberNavController()
 
     // TODO: 임시 로그인 상태 확인 -> AuthRepository에서 확인하도록 변경
-    val isLoggedIn = true
+    val isLoggedIn = false
 
     NavHost(
         navController = navController,
@@ -62,7 +64,22 @@ fun AppNavHost() {
                 navController.navigate(ROUTE_HOME) {
                     popUpTo(ROUTE_LOGIN) { inclusive = true } // 로그인 화면 스택 제거
                 }
-            })
+            },
+                onNavigateSignUp = {
+                    navController.navigate(ROUTE_SIGNUP)
+                })
+        }
+        composable(ROUTE_SIGNUP) {
+            SignUpScreen(
+                onSuccess = {
+                    navController.navigate(ROUTE_HOME) {
+                        popUpTo(ROUTE_LOGIN) { inclusive = true }
+                    }
+                },
+                onNavigateBack = {
+                    navController.navigateUp()
+                }
+            )
         }
         composable(ROUTE_HOME) { MainScreen(navController) }
         composable(ROUTE_PARTS) { PartScreen() }
diff --git a/app/src/main/java/com/sampoom/android/core/network/ErrorHandling.kt b/app/src/main/java/com/sampoom/android/core/network/ErrorHandling.kt
new file mode 100644
index 0000000..23d3ae5
--- /dev/null
+++ b/app/src/main/java/com/sampoom/android/core/network/ErrorHandling.kt
@@ -0,0 +1,26 @@
+package com.sampoom.android.core.network
+
+import com.google.gson.Gson
+import com.google.gson.JsonSyntaxException
+import retrofit2.HttpException
+
+data class ApiErrorResponse(
+    val code: Int? = null,
+    val message: String? = null
+)
+
+fun Throwable.serverMessageOrNull(): String? {
+    if (this is HttpException) {
+        val errorBody = response()?.errorBody()?.string() ?: return null
+        return try {
+            Gson().fromJson(errorBody, ApiErrorResponse::class.java).message
+        } catch (_: JsonSyntaxException) {
+            null
+        } catch (_: Exception) {
+            null
+        }
+    }
+    return null
+}
+
+
diff --git a/app/src/main/java/com/sampoom/android/core/network/NetworkModule.kt b/app/src/main/java/com/sampoom/android/core/network/NetworkModule.kt
index 4884ee1..fb48025 100644
--- a/app/src/main/java/com/sampoom/android/core/network/NetworkModule.kt
+++ b/app/src/main/java/com/sampoom/android/core/network/NetworkModule.kt
@@ -8,17 +8,37 @@ import okhttp3.OkHttpClient
 import retrofit2.Retrofit
 import retrofit2.converter.gson.GsonConverterFactory
 import javax.inject.Singleton
+import com.google.gson.GsonBuilder
+import com.google.gson.FieldNamingPolicy
+import com.sampoom.android.BuildConfig
+import okhttp3.logging.HttpLoggingInterceptor
+import java.util.concurrent.TimeUnit
 
 @Module
 @InstallIn(SingletonComponent::class)
 object NetworkModule {
-    @Provides @Singleton fun provideOkHttp(): OkHttpClient = OkHttpClient.Builder().build()
+    @Provides @Singleton fun provideOkHttp(): OkHttpClient = OkHttpClient.Builder()
+        .connectTimeout(30, TimeUnit.SECONDS)
+        .readTimeout(30, TimeUnit.SECONDS)
+        .writeTimeout(30, TimeUnit.SECONDS)
+        .addInterceptor(HttpLoggingInterceptor().apply {
+            level = if (BuildConfig.DEBUG)
+                HttpLoggingInterceptor.Level.BODY
+            else
+                HttpLoggingInterceptor.Level.NONE
+        })
+        // TODO: 로그인 기능 연동 후 인증 인터셉터 추가 필요
+        .build()
 
     @Provides @Singleton
-    fun provideRetrofit(client: OkHttpClient): Retrofit =
-        Retrofit.Builder()
-            .baseUrl("http://10.0.2.2:8080/api/")
+    fun provideRetrofit(client: OkHttpClient): Retrofit {
+        val gson = GsonBuilder()
+            .setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES)
+            .create()
+        return Retrofit.Builder()
+            .baseUrl("https://sampoom.store/api/")
             .client(client)
-            .addConverterFactory(GsonConverterFactory.create())
+            .addConverterFactory(GsonConverterFactory.create(gson))
             .build()
+    }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/sampoom/android/core/ui/component/CommonButton.kt b/app/src/main/java/com/sampoom/android/core/ui/component/CommonButton.kt
index a9ba4d0..ca17eca 100644
--- a/app/src/main/java/com/sampoom/android/core/ui/component/CommonButton.kt
+++ b/app/src/main/java/com/sampoom/android/core/ui/component/CommonButton.kt
@@ -1,8 +1,8 @@
 package com.sampoom.android.core.ui.component
 
 import androidx.compose.foundation.BorderStroke
+import androidx.compose.foundation.layout.RowScope
 import androidx.compose.foundation.layout.height
-import androidx.compose.foundation.layout.padding
 import androidx.compose.material3.Button
 import androidx.compose.material3.ButtonDefaults
 import androidx.compose.material3.FilledTonalButton
@@ -18,6 +18,10 @@ import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
+import com.sampoom.android.core.ui.theme.Main500
+import com.sampoom.android.core.ui.theme.White
+import com.sampoom.android.core.ui.theme.disableColor
+import com.sampoom.android.core.ui.theme.textSecondaryColor
 
 /**
  * Sampoom common button with multiple visual variants.
@@ -40,15 +44,14 @@ import androidx.compose.ui.unit.dp
  */
 @Composable
 fun CommonButton(
-    text: String,
     modifier: Modifier = Modifier,
     enabled: Boolean = true,
     variant: ButtonVariant = ButtonVariant.Primary,
     size: ButtonSize = ButtonSize.Large,
     leadingIcon: (@Composable (() -> Unit))? = null,
-    onClick: () -> Unit
+    onClick: () -> Unit,
+    content: @Composable RowScope.() -> Unit
 ) {
-    val cs = MaterialTheme.colorScheme
     val shape = MaterialTheme.shapes.large
     val height = when (size) {
         ButtonSize.Large -> 56.dp
@@ -64,21 +67,14 @@ fun CommonButton(
                 shape = shape,
                 modifier = modifier.height(height),
                 colors = ButtonDefaults.buttonColors(
-                    containerColor = cs.primary,
-                    contentColor = cs.onPrimary,
-                    disabledContainerColor = cs.onSurface.copy(alpha = 0.12f),
-                    disabledContentColor = cs.onSurface.copy(alpha = 0.38f),
+                    containerColor = Main500,
+                    contentColor = White,
+                    disabledContainerColor = disableColor(),
+                    disabledContentColor = textSecondaryColor()
                 )
             ) {
-                if (leadingIcon != null) {
-                    leadingIcon()
-                }
-                Text(
-                    text = text,
-                    style = MaterialTheme.typography.labelLarge,
-                    fontWeight = FontWeight.SemiBold,
-                    modifier = Modifier.padding(start = if (leadingIcon != null) 8.dp else 0.dp)
-                )
+                if (leadingIcon != null) leadingIcon()
+                content()
             }
         }
 
@@ -90,21 +86,14 @@ fun CommonButton(
                 shape = shape,
                 modifier = modifier.height(height),
                 colors = ButtonDefaults.filledTonalButtonColors(
-                    containerColor = cs.secondaryContainer,
-                    contentColor = cs.onSecondaryContainer,
-                    disabledContainerColor = cs.onSurface.copy(alpha = 0.08f),
-                    disabledContentColor = cs.onSurface.copy(alpha = 0.38f)
+                    containerColor = Main500,
+                    contentColor = White,
+                    disabledContainerColor = disableColor(),
+                    disabledContentColor = textSecondaryColor()
                 )
             ) {
-                if (leadingIcon != null) {
-                    leadingIcon()
-                }
-                Text(
-                    text = text,
-                    style = MaterialTheme.typography.labelLarge,
-                    fontWeight = FontWeight.SemiBold,
-                    modifier = Modifier.padding(start = if (leadingIcon != null) 8.dp else 0.dp)
-                )
+                if (leadingIcon != null) leadingIcon()
+                content()
             }
         }
 
@@ -115,17 +104,14 @@ fun CommonButton(
                 enabled = enabled,
                 shape = shape,
                 modifier = modifier.height(height),
-                border = BorderStroke(1.dp, cs.primary),
+                border = BorderStroke(1.dp, Main500),
                 colors = ButtonDefaults.outlinedButtonColors(
-                    contentColor = cs.primary,
-                    disabledContentColor = cs.onSurface.copy(alpha = 0.38f)
+                    contentColor = Main500,
+                    disabledContentColor = textSecondaryColor()
                 )
             ) {
-                Text(
-                    text = text,
-                    style = MaterialTheme.typography.labelLarge,
-                    fontWeight = FontWeight.SemiBold
-                )
+                if (leadingIcon != null) leadingIcon()
+                content()
             }
         }
 
@@ -137,15 +123,12 @@ fun CommonButton(
                 shape = shape,
                 modifier = modifier.height(height),
                 colors = ButtonDefaults.textButtonColors(
-                    contentColor = cs.onSurface,
-                    disabledContentColor = cs.onSurface.copy(alpha = 0.38f)
+                    contentColor = textSecondaryColor(),
+                    disabledContentColor = textSecondaryColor()
                 )
             ) {
-                Text(
-                    text = text,
-                    style = MaterialTheme.typography.labelLarge,
-                    fontWeight = FontWeight.SemiBold
-                )
+                if (leadingIcon != null) leadingIcon()
+                content()
             }
         }
 
@@ -159,15 +142,12 @@ fun CommonButton(
                 colors = ButtonDefaults.buttonColors(
                     containerColor = Color(0xFF000000),
                     contentColor = Color.White,
-                    disabledContainerColor = cs.onSurface.copy(alpha = 0.12f),
-                    disabledContentColor = cs.onSurface.copy(alpha = 0.38f),
+                    disabledContainerColor = disableColor(),
+                    disabledContentColor = textSecondaryColor()
                 )
             ) {
-                Text(
-                    text = text,
-                    style = MaterialTheme.typography.labelLarge,
-                    fontWeight = FontWeight.SemiBold
-                )
+                if (leadingIcon != null) leadingIcon()
+                content()
             }
         }
     }
@@ -197,7 +177,7 @@ enum class ButtonSize { Large, Medium, Small }
 private fun CommonButtonPreview_All() {
     // Primary
     CommonButton(
-        text = "Button",
+        content = { Text("Button", fontWeight = FontWeight.Bold) },
         variant = ButtonVariant.Primary,
         onClick = {}
     )
@@ -207,7 +187,7 @@ private fun CommonButtonPreview_All() {
 @Composable
 private fun CommonButtonPreview_Primary_WithIcon() {
     CommonButton(
-        text = "Button",
+        content = { Text("Button", fontWeight = FontWeight.Bold) },
         variant = ButtonVariant.Primary,
         leadingIcon = { Icon(painterResource(android.R.drawable.ic_menu_call), contentDescription = null) },
         onClick = {}
@@ -218,7 +198,7 @@ private fun CommonButtonPreview_Primary_WithIcon() {
 @Composable
 private fun CommonButtonPreview_Tonal() {
     CommonButton(
-        text = "Button",
+        content = { Text("Button", fontWeight = FontWeight.Bold) },
         variant = ButtonVariant.Secondary,
         onClick = {}
     )
@@ -228,7 +208,7 @@ private fun CommonButtonPreview_Tonal() {
 @Composable
 private fun CommonButtonPreview_Outlined() {
     CommonButton(
-        text = "Button",
+        content = { Text("Button", fontWeight = FontWeight.Bold) },
         variant = ButtonVariant.Outlined,
         onClick = {}
     )
@@ -238,7 +218,7 @@ private fun CommonButtonPreview_Outlined() {
 @Composable
 private fun CommonButtonPreview_Ghost() {
     CommonButton(
-        text = "Button",
+        content = { Text("Button", fontWeight = FontWeight.Bold) },
         variant = ButtonVariant.Ghost,
         onClick = {}
     )
@@ -248,7 +228,7 @@ private fun CommonButtonPreview_Ghost() {
 @Composable
 private fun CommonButtonPreview_Neutral_Disabled() {
     CommonButton(
-        text = "Button",
+        content = { Text("Button", fontWeight = FontWeight.Bold) },
         variant = ButtonVariant.Neutral,
         enabled = false,
         onClick = {}
diff --git a/app/src/main/java/com/sampoom/android/core/ui/component/CommonSnackBar.kt b/app/src/main/java/com/sampoom/android/core/ui/component/CommonSnackBar.kt
new file mode 100644
index 0000000..34bfee0
--- /dev/null
+++ b/app/src/main/java/com/sampoom/android/core/ui/component/CommonSnackBar.kt
@@ -0,0 +1,114 @@
+package com.sampoom.android.core.ui.component
+
+import androidx.compose.material3.SnackbarDuration
+import androidx.compose.material3.SnackbarHost
+import androidx.compose.material3.SnackbarHostState
+import androidx.compose.material3.SnackbarResult
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.remember
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.padding
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.Dp
+import androidx.compose.foundation.layout.WindowInsets
+import androidx.compose.foundation.layout.asPaddingValues
+import androidx.compose.foundation.layout.statusBars
+import com.sampoom.android.core.ui.theme.backgroundCardColor
+import com.sampoom.android.core.ui.theme.textColor
+import androidx.compose.material3.Surface
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.layout.wrapContentWidth
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.Icon
+import androidx.compose.ui.res.painterResource
+import com.sampoom.android.R
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.ui.res.stringResource
+
+@Composable
+fun rememberCommonSnackBarHostState(): SnackbarHostState = remember { SnackbarHostState() }
+
+@Composable
+fun ShowErrorSnackBar(
+    errorMessage: String?,
+    snackBarHostState: SnackbarHostState,
+    onConsumed: () -> Unit,
+    actionLabel: String? = null,
+    onAction: (() -> Unit)? = null,
+    duration: SnackbarDuration = SnackbarDuration.Short
+) {
+    LaunchedEffect(errorMessage) {
+        val message = errorMessage ?: return@LaunchedEffect
+        val result = snackBarHostState.showSnackbar(
+            message = message,
+            actionLabel = actionLabel,
+            withDismissAction = true,
+            duration = duration
+        )
+        if (result == SnackbarResult.ActionPerformed) {
+            onAction?.invoke()
+        }
+        onConsumed()
+    }
+}
+
+@Composable
+fun TopSnackBarHost(
+    hostState: SnackbarHostState,
+    extraTopPadding: Dp = 0.dp,
+    showDismissButton: Boolean = true
+) {
+    Box(modifier = Modifier.fillMaxSize()) {
+        val statusBarTop = WindowInsets.statusBars.asPaddingValues().calculateTopPadding()
+        SnackbarHost(
+            hostState = hostState,
+            modifier = Modifier
+                .align(Alignment.TopCenter)
+                .padding(top = statusBarTop + extraTopPadding, start = 16.dp, end = 16.dp),
+            snackbar = { data ->
+                Surface(
+                    color = backgroundCardColor(),
+                    contentColor = textColor(),
+                    shape = RoundedCornerShape(12.dp),
+                    tonalElevation = 6.dp,
+                ) {
+                    Row(
+                        modifier = Modifier
+                            .padding(horizontal = 16.dp, vertical = 8.dp)
+                            .wrapContentWidth(),
+                        verticalAlignment = Alignment.CenterVertically
+                    ) {
+                        Text(data.visuals.message)
+                        Spacer(Modifier.width(12.dp))
+                        val label = data.visuals.actionLabel
+                        if (label != null) {
+                            TextButton(onClick = { data.performAction() }) {
+                                Text(text = label, color = textColor())
+                            }
+                            Spacer(Modifier.width(8.dp))
+                        }
+                        if (showDismissButton) {
+                            IconButton(onClick = { data.dismiss() }) {
+                                Icon(
+                                    painter = painterResource(id = R.drawable.outline_close),
+                                    contentDescription = stringResource(R.string.common_close),
+                                    tint = textColor()
+                                )
+                            }
+                        }
+                    }
+                }
+            }
+        )
+    }
+}
+
+
diff --git a/app/src/main/java/com/sampoom/android/core/ui/component/CommonTextField.kt b/app/src/main/java/com/sampoom/android/core/ui/component/CommonTextField.kt
index 52ba4bf..51d8feb 100644
--- a/app/src/main/java/com/sampoom/android/core/ui/component/CommonTextField.kt
+++ b/app/src/main/java/com/sampoom/android/core/ui/component/CommonTextField.kt
@@ -1,10 +1,13 @@
 package com.sampoom.android.core.ui.component
 
+import android.R.attr.singleLine
+import android.R.attr.text
 import androidx.compose.foundation.isSystemInDarkTheme
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.foundation.text.input.InputTransformation.Companion.keyboardOptions
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.Visibility
 import androidx.compose.material.icons.filled.VisibilityOff
@@ -17,32 +20,36 @@ import androidx.compose.ui.text.input.PasswordVisualTransformation
 import androidx.compose.ui.text.input.VisualTransformation
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
+import com.sampoom.android.core.ui.theme.FailRed
+import com.sampoom.android.core.ui.theme.Main500
+import com.sampoom.android.core.ui.theme.backgroundColor
 
 enum class TextFieldVariant { Outlined, Filled }
 
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
 fun CommonTextField(
+    modifier: Modifier = Modifier,
     value: String,
     onValueChange: (String) -> Unit,
-    label: String,
     placeholder: String,
-    modifier: Modifier = Modifier,
     enabled: Boolean = true,
     isPassword: Boolean = false,
-    variant: TextFieldVariant = TextFieldVariant.Outlined
+    variant: TextFieldVariant = TextFieldVariant.Outlined,
+    isError: Boolean = false,
+    errorMessage: String? = null
 ) {
     var passwordVisible by remember { mutableStateOf(false) }
-    val darkTheme = isSystemInDarkTheme()
-    val cs = MaterialTheme.colorScheme
 
-    val textColor = if (darkTheme) Color.White else Color.Black
-    val containerColor = if (variant == TextFieldVariant.Filled) {
-        if (darkTheme) Color(0xFF1C1C1E) else Color(0xFFF3F3F3)
-    } else Color.Transparent
+    val textColor = if (isSystemInDarkTheme()) Color.White else Color.Black
+    val containerColor = if (variant == TextFieldVariant.Filled) backgroundColor() else Color.Transparent
 
-    val focusedBorderColor = cs.primary
-    val unfocusedBorderColor = if (darkTheme) Color(0xFF666666) else Color(0xFFCCCCCC)
+    val focusedBorderColor = if (isError) FailRed else Main500
+    val unfocusedBorderColor = when {
+        isError -> FailRed
+        isSystemInDarkTheme() -> Color(0xFF666666)
+        else -> Color(0xFFCCCCCC)
+    }
 
     val trailingIconView = if (isPassword) {
         @Composable {
@@ -50,30 +57,43 @@ fun CommonTextField(
                 Icon(
                     imageVector = if (passwordVisible) Icons.Default.Visibility else Icons.Default.VisibilityOff,
                     contentDescription = null,
-                    tint = if (darkTheme) Color.White else Color.Black
+                    tint = textColor
                 )
             }
         }
     } else null
 
+    // 에러 메시지 표시용
+    val supportingTextView = if (isError && errorMessage != null) {
+        @Composable {
+            Text(
+                text = errorMessage,
+                color = FailRed,
+                style = MaterialTheme.typography.bodySmall
+            )
+        }
+    } else null
+
     when (variant) {
         TextFieldVariant.Outlined -> {
             OutlinedTextField(
                 value = value,
                 onValueChange = onValueChange,
-                label = { Text(text = label, color = textColor) },
                 placeholder = { Text(text = placeholder, color = textColor.copy(alpha = 0.4f)) },
                 modifier = modifier
                     .fillMaxWidth()
                     .padding(vertical = 4.dp),
                 singleLine = true,
                 enabled = enabled,
+                isError = isError,
                 trailingIcon = trailingIconView,
+                supportingText = supportingTextView,
                 visualTransformation = if (isPassword && !passwordVisible) PasswordVisualTransformation() else VisualTransformation.None,
                 keyboardOptions = KeyboardOptions(keyboardType = if (isPassword) KeyboardType.Password else KeyboardType.Text),
                 colors = OutlinedTextFieldDefaults.colors(
                     focusedBorderColor = focusedBorderColor,
                     unfocusedBorderColor = unfocusedBorderColor,
+                    errorBorderColor = FailRed,
                     disabledBorderColor = Color.Gray,
                     focusedLabelColor = focusedBorderColor,
                     unfocusedLabelColor = textColor.copy(alpha = 0.7f),
@@ -81,7 +101,7 @@ fun CommonTextField(
                     focusedTextColor = textColor,
                     unfocusedTextColor = textColor
                 ),
-                shape = MaterialTheme.shapes.medium
+                shape = MaterialTheme.shapes.large
             )
         }
 
@@ -89,19 +109,21 @@ fun CommonTextField(
             TextField(
                 value = value,
                 onValueChange = onValueChange,
-                label = { Text(text = label, color = textColor) },
                 placeholder = { Text(text = placeholder, color = textColor.copy(alpha = 0.4f)) },
                 modifier = modifier
                     .fillMaxWidth()
                     .padding(vertical = 4.dp),
                 singleLine = true,
                 enabled = enabled,
+                isError = isError,
                 trailingIcon = trailingIconView,
+                supportingText = supportingTextView,
                 visualTransformation = if (isPassword && !passwordVisible) PasswordVisualTransformation() else VisualTransformation.None,
                 keyboardOptions = KeyboardOptions(keyboardType = if (isPassword) KeyboardType.Password else KeyboardType.Text),
                 colors = TextFieldDefaults.colors(
                     focusedContainerColor = containerColor,
                     unfocusedContainerColor = containerColor,
+                    errorContainerColor = FailRed,
                     disabledContainerColor = containerColor.copy(alpha = 0.5f),
                     focusedIndicatorColor = focusedBorderColor,
                     unfocusedIndicatorColor = unfocusedBorderColor,
@@ -109,7 +131,7 @@ fun CommonTextField(
                     focusedTextColor = textColor,
                     unfocusedTextColor = textColor
                 ),
-                shape = MaterialTheme.shapes.medium
+                shape = MaterialTheme.shapes.large
             )
         }
     }
@@ -123,14 +145,12 @@ fun Preview_Light_CommonTextFields() {
             CommonTextField(
                 value = "Example@naver.com",
                 onValueChange = {},
-                label = "이메일 입력",
                 placeholder = "Example@naver.com",
                 variant = TextFieldVariant.Outlined
             )
             CommonTextField(
                 value = "",
                 onValueChange = {},
-                label = "비밀번호 입력",
                 placeholder = "비밀번호 입력",
                 isPassword = true,
                 variant = TextFieldVariant.Outlined
@@ -144,20 +164,33 @@ fun Preview_Light_CommonTextFields() {
 fun Preview_Dark_CommonTextFields() {
     MaterialTheme(colorScheme = darkColorScheme()) {
         Column {
+            // 정상
             CommonTextField(
                 value = "Example@naver.com",
                 onValueChange = {},
-                label = "이메일 입력",
-                placeholder = "Example@naver.com",
-                variant = TextFieldVariant.Filled
+                placeholder = "이메일",
+                variant = TextFieldVariant.Outlined
             )
+
+            // 에러
             CommonTextField(
-                value = "",
+                value = "invalid",
                 onValueChange = {},
-                label = "비밀번호 입력",
-                placeholder = "비밀번호 입력",
+                placeholder = "이메일",
+                variant = TextFieldVariant.Outlined,
+                isError = true,
+                errorMessage = "올바른 이메일 형식이 아닙니다"
+            )
+
+            // 비밀번호 에러
+            CommonTextField(
+                value = "123",
+                onValueChange = {},
+                placeholder = "비밀번호",
                 isPassword = true,
-                variant = TextFieldVariant.Filled
+                variant = TextFieldVariant.Outlined,
+                isError = true,
+                errorMessage = "비밀번호는 최소 8자 이상이어야 합니다"
             )
         }
     }
diff --git a/app/src/main/java/com/sampoom/android/core/ui/theme/Color.kt b/app/src/main/java/com/sampoom/android/core/ui/theme/Color.kt
index 14c8259..72cdc9c 100644
--- a/app/src/main/java/com/sampoom/android/core/ui/theme/Color.kt
+++ b/app/src/main/java/com/sampoom/android/core/ui/theme/Color.kt
@@ -1,11 +1,47 @@
 package com.sampoom.android.core.ui.theme
 
+import androidx.compose.foundation.isSystemInDarkTheme
+import androidx.compose.runtime.Composable
 import androidx.compose.ui.graphics.Color
 
-val Purple80 = Color(0xFFD0BCFF)
-val PurpleGrey80 = Color(0xFFCCC2DC)
-val Pink80 = Color(0xFFEFB8C8)
+val White = Color(0xFFFFFFFF)
+val Black = Color(0xFF000000)
 
-val Purple40 = Color(0xFF6650a4)
-val PurpleGrey40 = Color(0xFF625b71)
-val Pink40 = Color(0xFF7D5260)
\ No newline at end of file
+val SuccessGreen = Color(0xFF10B981)
+val FailRed = Color(0xFFFF6C6C)
+val WaitYellow = Color(0xFFF59E0B)
+
+val Grey400 = Color(0xFF444444)
+val Grey300 = Color(0xFF7C7C7C)
+val Grey200 = Color(0xFFCCCCCC)
+val Grey100 = Color(0xFFE9EAEC)
+
+val BgWhite = Color(0xFFF5F5F5)
+val BgCardWhite = Color(0xFFFFFFFF)
+val BgBlack = Color(0xFF17181B)
+val BgCardBlack = Color(0xFF36393F)
+
+val Main900 = Color(0xFF1F1F5C)
+val Main800 = Color(0xFF333399)
+val Main700 = Color(0xFF4C4CBB)
+val Main600 = Color(0xFF6666DD)
+val Main500 = Color(0xFF8080FF)
+val Main400 = Color(0xFF9999FF)
+val Main300 = Color(0xFFB3B3FF)
+val Main200 = Color(0xFFCCCCFF)
+val Main100 = Color(0xFFE6E6FF)
+
+@Composable
+fun backgroundColor() = if (isSystemInDarkTheme()) BgBlack else BgWhite
+
+@Composable
+fun backgroundCardColor() = if (isSystemInDarkTheme()) BgCardBlack else BgCardWhite
+
+@Composable
+fun textColor() = if (isSystemInDarkTheme()) BgWhite else BgCardBlack
+
+@Composable
+fun textSecondaryColor() = if (isSystemInDarkTheme()) Grey200 else Grey300
+
+@Composable
+fun disableColor() = if (isSystemInDarkTheme()) Grey400 else Grey100
\ No newline at end of file
diff --git a/app/src/main/java/com/sampoom/android/core/ui/theme/Theme.kt b/app/src/main/java/com/sampoom/android/core/ui/theme/Theme.kt
index 26b2837..9c55a3d 100644
--- a/app/src/main/java/com/sampoom/android/core/ui/theme/Theme.kt
+++ b/app/src/main/java/com/sampoom/android/core/ui/theme/Theme.kt
@@ -11,15 +11,15 @@ import androidx.compose.runtime.Composable
 import androidx.compose.ui.platform.LocalContext
 
 private val DarkColorScheme = darkColorScheme(
-    primary = Purple80,
-    secondary = PurpleGrey80,
-    tertiary = Pink80
+    primary = Main500,
+    secondary = Main300,
+    tertiary = Main100
 )
 
 private val LightColorScheme = lightColorScheme(
-    primary = Purple40,
-    secondary = PurpleGrey40,
-    tertiary = Pink40
+    primary = Main500,
+    secondary = Main300,
+    tertiary = Main100
 
     /* Other default colors to override
     background = Color(0xFFFFFBFE),
diff --git a/app/src/main/java/com/sampoom/android/core/ui/theme/Type.kt b/app/src/main/java/com/sampoom/android/core/ui/theme/Type.kt
index 6a3a086..ed5af64 100644
--- a/app/src/main/java/com/sampoom/android/core/ui/theme/Type.kt
+++ b/app/src/main/java/com/sampoom/android/core/ui/theme/Type.kt
@@ -1,34 +1,33 @@
 package com.sampoom.android.core.ui.theme
 
 import androidx.compose.material3.Typography
-import androidx.compose.ui.text.TextStyle
+import androidx.compose.ui.text.font.Font
 import androidx.compose.ui.text.font.FontFamily
 import androidx.compose.ui.text.font.FontWeight
-import androidx.compose.ui.unit.sp
+import com.sampoom.android.R
+
+val GmarketSansFamily = FontFamily(
+    Font(R.font.gmarket_sans_light, FontWeight.Light),
+    Font(R.font.gmarket_sans_medium, FontWeight.Medium),
+    Font(R.font.gmarket_sans_bold, FontWeight.Bold)
+)
 
 // Set of Material typography styles to start with
+private val baseTypography = Typography()
 val Typography = Typography(
-    bodyLarge = TextStyle(
-        fontFamily = FontFamily.Default,
-        fontWeight = FontWeight.Normal,
-        fontSize = 16.sp,
-        lineHeight = 24.sp,
-        letterSpacing = 0.5.sp
-    )
-    /* Other default text styles to override
-    titleLarge = TextStyle(
-        fontFamily = FontFamily.Default,
-        fontWeight = FontWeight.Normal,
-        fontSize = 22.sp,
-        lineHeight = 28.sp,
-        letterSpacing = 0.sp
-    ),
-    labelSmall = TextStyle(
-        fontFamily = FontFamily.Default,
-        fontWeight = FontWeight.Medium,
-        fontSize = 11.sp,
-        lineHeight = 16.sp,
-        letterSpacing = 0.5.sp
-    )
-    */
+    displayLarge = baseTypography.displayLarge.copy(fontFamily = GmarketSansFamily),
+    displayMedium = baseTypography.displayMedium.copy(fontFamily = GmarketSansFamily),
+    displaySmall = baseTypography.displaySmall.copy(fontFamily = GmarketSansFamily),
+    headlineLarge = baseTypography.headlineLarge.copy(fontFamily = GmarketSansFamily),
+    headlineMedium = baseTypography.headlineMedium.copy(fontFamily = GmarketSansFamily),
+    headlineSmall = baseTypography.headlineSmall.copy(fontFamily = GmarketSansFamily),
+    titleLarge = baseTypography.titleLarge.copy(fontFamily = GmarketSansFamily),
+    titleMedium = baseTypography.titleMedium.copy(fontFamily = GmarketSansFamily),
+    titleSmall = baseTypography.titleSmall.copy(fontFamily = GmarketSansFamily),
+    bodyLarge = baseTypography.bodyLarge.copy(fontFamily = GmarketSansFamily),
+    bodyMedium = baseTypography.bodyMedium.copy(fontFamily = GmarketSansFamily),
+    bodySmall = baseTypography.bodySmall.copy(fontFamily = GmarketSansFamily),
+    labelLarge = baseTypography.labelLarge.copy(fontFamily = GmarketSansFamily),
+    labelMedium = baseTypography.labelMedium.copy(fontFamily = GmarketSansFamily),
+    labelSmall = baseTypography.labelSmall.copy(fontFamily = GmarketSansFamily)
 )
\ No newline at end of file
diff --git a/app/src/main/java/com/sampoom/android/feature/auth/data/local/database/.gitkeep b/app/src/main/java/com/sampoom/android/feature/auth/data/local/database/.gitkeep
deleted file mode 100644
index e69de29..0000000
diff --git a/app/src/main/java/com/sampoom/android/feature/auth/data/local/preferences/AuthPreferences.kt b/app/src/main/java/com/sampoom/android/feature/auth/data/local/preferences/AuthPreferences.kt
index 8345a3f..789a143 100644
--- a/app/src/main/java/com/sampoom/android/feature/auth/data/local/preferences/AuthPreferences.kt
+++ b/app/src/main/java/com/sampoom/android/feature/auth/data/local/preferences/AuthPreferences.kt
@@ -1,21 +1,50 @@
 package com.sampoom.android.feature.auth.data.local.preferences
 
 import android.content.Context
+import androidx.datastore.preferences.core.Preferences
+import androidx.datastore.preferences.core.edit
+import androidx.datastore.preferences.core.stringPreferencesKey
+import androidx.datastore.preferences.preferencesDataStore
 import dagger.hilt.android.qualifiers.ApplicationContext
 import javax.inject.Inject
 import javax.inject.Singleton
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.runBlocking
+
+// Per official guidance, DataStore instance should be single and at top-level.
+private val Context.authDataStore by preferencesDataStore(name = "auth_prefs")
 
 @Singleton
 class AuthPreferences @Inject constructor(
-    @ApplicationContext private val context: Context
+    @param:ApplicationContext private val context: Context
 ){
-    private val sharedPreferences = context.getSharedPreferences("auth", Context.MODE_PRIVATE)
+    private val dataStore = context.authDataStore
 
-    fun saveToken(token: String) {
-        sharedPreferences.edit().putString("token", token)
+    private object Keys {
+        val ACCESS_TOKEN: Preferences.Key<String> = stringPreferencesKey("access_token")
+        val REFRESH_TOKEN: Preferences.Key<String> = stringPreferencesKey("refresh_token")
     }
-    fun clear() {
-        sharedPreferences.edit().clear().apply()
+
+    // Suspend save to avoid blocking thread
+    suspend fun saveToken(accessToken: String, refreshToken: String) {
+        dataStore.edit { prefs ->
+            prefs[Keys.ACCESS_TOKEN] = accessToken
+            prefs[Keys.REFRESH_TOKEN] = refreshToken
+        }
     }
-    fun hasToken(): Boolean = !sharedPreferences.getString("token", null).isNullOrEmpty()
+
+    // Synchronous getters backed by runBlocking for minimal surface change
+    fun getAccessToken(): String? = runBlocking {
+        dataStore.data.first()[Keys.ACCESS_TOKEN]
+    }
+
+    fun getRefreshToken(): String? = runBlocking {
+        dataStore.data.first()[Keys.REFRESH_TOKEN]
+    }
+
+    suspend fun clear() {
+        dataStore.edit { it.clear() }
+    }
+
+    fun hasToken(): Boolean = !getAccessToken().isNullOrEmpty() && !getRefreshToken().isNullOrEmpty()
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/sampoom/android/feature/auth/data/mapper/AuthMappers.kt b/app/src/main/java/com/sampoom/android/feature/auth/data/mapper/AuthMappers.kt
index c6bf3b0..b79dea4 100644
--- a/app/src/main/java/com/sampoom/android/feature/auth/data/mapper/AuthMappers.kt
+++ b/app/src/main/java/com/sampoom/android/feature/auth/data/mapper/AuthMappers.kt
@@ -1,6 +1,6 @@
 package com.sampoom.android.feature.auth.data.mapper
 
-import com.sampoom.android.feature.auth.data.remote.dto.UserDto
+import com.sampoom.android.feature.auth.data.remote.dto.LoginResponseDto
 import com.sampoom.android.feature.auth.domain.model.User
 
-fun UserDto.toModel(): User = User(id, name, email, token)
\ No newline at end of file
+fun LoginResponseDto.toModel(): User = User(userId, userName, role, accessToken, refreshToken, expiresIn)
\ No newline at end of file
diff --git a/app/src/main/java/com/sampoom/android/feature/auth/data/remote/api/AuthApi.kt b/app/src/main/java/com/sampoom/android/feature/auth/data/remote/api/AuthApi.kt
index ce4be9b..74ff84f 100644
--- a/app/src/main/java/com/sampoom/android/feature/auth/data/remote/api/AuthApi.kt
+++ b/app/src/main/java/com/sampoom/android/feature/auth/data/remote/api/AuthApi.kt
@@ -1,11 +1,17 @@
 package com.sampoom.android.feature.auth.data.remote.api
 
+import com.sampoom.android.core.network.ApiResponse
 import com.sampoom.android.feature.auth.data.remote.dto.LoginRequestDto
-import com.sampoom.android.feature.auth.data.remote.dto.UserDto
+import com.sampoom.android.feature.auth.data.remote.dto.SignUpRequestDto
+import com.sampoom.android.feature.auth.data.remote.dto.SignUpResponseDto
+import com.sampoom.android.feature.auth.data.remote.dto.LoginResponseDto
 import retrofit2.http.Body
 import retrofit2.http.POST
 
 interface AuthApi {
-    @POST("auth/login")
-    suspend fun login(@Body body: LoginRequestDto): UserDto
+    @POST("login")
+    suspend fun login(@Body body: LoginRequestDto): ApiResponse<LoginResponseDto>
+
+    @POST("signup")
+    suspend fun signUp(@Body body: SignUpRequestDto): ApiResponse<SignUpResponseDto>
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/sampoom/android/feature/auth/data/remote/dto/LoginResponseDto.kt b/app/src/main/java/com/sampoom/android/feature/auth/data/remote/dto/LoginResponseDto.kt
new file mode 100644
index 0000000..3d44982
--- /dev/null
+++ b/app/src/main/java/com/sampoom/android/feature/auth/data/remote/dto/LoginResponseDto.kt
@@ -0,0 +1,10 @@
+package com.sampoom.android.feature.auth.data.remote.dto
+
+data class LoginResponseDto(
+    val userId: Long,
+    val userName: String,
+    val role: String,
+    val accessToken: String,
+    val refreshToken: String,
+    val expiresIn: Int
+)
diff --git a/app/src/main/java/com/sampoom/android/feature/auth/data/remote/dto/SignUpRequestDto.kt b/app/src/main/java/com/sampoom/android/feature/auth/data/remote/dto/SignUpRequestDto.kt
new file mode 100644
index 0000000..ff24ca2
--- /dev/null
+++ b/app/src/main/java/com/sampoom/android/feature/auth/data/remote/dto/SignUpRequestDto.kt
@@ -0,0 +1,10 @@
+package com.sampoom.android.feature.auth.data.remote.dto
+
+data class SignUpRequestDto(
+    val name: String,
+    val workspace: String,
+    val branch: String,
+    val position: String,
+    val email: String,
+    val password: String
+)
\ No newline at end of file
diff --git a/app/src/main/java/com/sampoom/android/feature/auth/data/remote/dto/SignUpResponseDto.kt b/app/src/main/java/com/sampoom/android/feature/auth/data/remote/dto/SignUpResponseDto.kt
new file mode 100644
index 0000000..d683a69
--- /dev/null
+++ b/app/src/main/java/com/sampoom/android/feature/auth/data/remote/dto/SignUpResponseDto.kt
@@ -0,0 +1,7 @@
+package com.sampoom.android.feature.auth.data.remote.dto
+
+data class SignUpResponseDto(
+    val userId: Long,
+    val userName: String,
+    val email: String
+)
diff --git a/app/src/main/java/com/sampoom/android/feature/auth/data/remote/dto/UserDto.kt b/app/src/main/java/com/sampoom/android/feature/auth/data/remote/dto/UserDto.kt
deleted file mode 100644
index 38f07e2..0000000
--- a/app/src/main/java/com/sampoom/android/feature/auth/data/remote/dto/UserDto.kt
+++ /dev/null
@@ -1,8 +0,0 @@
-package com.sampoom.android.feature.auth.data.remote.dto
-
-data class UserDto(
-    val id: String,
-    val name: String,
-    val email: String,
-    val token: String
-)
diff --git a/app/src/main/java/com/sampoom/android/feature/auth/data/repository/AuthRepositoryImpl.kt b/app/src/main/java/com/sampoom/android/feature/auth/data/repository/AuthRepositoryImpl.kt
index 1d72da4..673d57a 100644
--- a/app/src/main/java/com/sampoom/android/feature/auth/data/repository/AuthRepositoryImpl.kt
+++ b/app/src/main/java/com/sampoom/android/feature/auth/data/repository/AuthRepositoryImpl.kt
@@ -4,6 +4,7 @@ import com.sampoom.android.feature.auth.data.local.preferences.AuthPreferences
 import com.sampoom.android.feature.auth.data.mapper.toModel
 import com.sampoom.android.feature.auth.data.remote.api.AuthApi
 import com.sampoom.android.feature.auth.data.remote.dto.LoginRequestDto
+import com.sampoom.android.feature.auth.data.remote.dto.SignUpRequestDto
 import com.sampoom.android.feature.auth.domain.model.User
 import com.sampoom.android.feature.auth.domain.repository.AuthRepository
 import javax.inject.Inject
@@ -12,19 +13,35 @@ class AuthRepositoryImpl @Inject constructor(
     private val api: AuthApi,
     private val preferences: AuthPreferences
 ) : AuthRepository {
+    override suspend fun signUp(
+        name: String,
+        workspace: String,
+        branch: String,
+        position: String,
+        email: String,
+        password: String
+    ): User {
+        api.signUp(SignUpRequestDto(
+            name = name,
+            workspace = workspace,
+            branch = branch,
+            position = position,
+            email = email,
+            password = password
+        ))
+        return signIn(email, password)
+    }
+
     override suspend fun signIn(
         email: String,
         password: String
     ): User {
         val dto = api.login(LoginRequestDto(email, password))
-        preferences.saveToken(dto.token)
-        return dto.toModel()
+        preferences.saveToken(dto.data.accessToken, dto.data.refreshToken)
+        return dto.data.toModel()
     }
 
-    override suspend fun signOut() {
-        preferences.clear()
-    }
+    override suspend fun signOut() { preferences.clear() }
 
     override fun isSignedIn(): Boolean = preferences.hasToken()
-
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/sampoom/android/feature/auth/domain/AuthValidator.kt b/app/src/main/java/com/sampoom/android/feature/auth/domain/AuthValidator.kt
new file mode 100644
index 0000000..b7c4516
--- /dev/null
+++ b/app/src/main/java/com/sampoom/android/feature/auth/domain/AuthValidator.kt
@@ -0,0 +1,72 @@
+package com.sampoom.android.feature.auth.domain
+
+import com.sampoom.android.R
+
+object AuthValidator {
+    // 이메일 형식 검증
+    fun validateEmail(email: String): ValidationResult {
+        if (email.isBlank()) {
+            return ValidationResult.Error(R.string.validation_email_required)
+        }
+
+        val emailPattern = "[a-zA-Z0-9._-]+@[a-z]+\\.+[a-z]+".toRegex()
+        if (!email.matches(emailPattern)) {
+            return ValidationResult.Error(R.string.validation_email_invalid)
+        }
+
+        return ValidationResult.Success
+    }
+
+    // 비밀번호 검증 (8-30자, 영문+숫자+특수문자 각 1개 이상)
+    fun validatePassword(password: String): ValidationResult {
+        if (password.isBlank()) {
+            return ValidationResult.Error(R.string.validation_password_required)
+        }
+
+        if (password.length < 8) {
+            return ValidationResult.Error(R.string.validation_password_min_length)
+        }
+
+        if (password.length > 30) {
+            return ValidationResult.Error(R.string.validation_password_max_length)
+        }
+
+        val hasLetter = password.any { it.isLetter() }
+        val hasDigit = password.any { it.isDigit() }
+        val hasSpecial = password.any { !it.isLetterOrDigit() }
+
+        if (!hasLetter || !hasDigit || !hasSpecial) {
+            return ValidationResult.Error(R.string.validation_password_complexity)
+        }
+
+        return ValidationResult.Success
+    }
+
+    // 비밀번호 확인 검증
+    fun validatePasswordCheck(password: String, passwordConfirm: String): ValidationResult {
+        if (passwordConfirm.isBlank()) {
+            return ValidationResult.Error(R.string.validation_password_confirm_required)
+        }
+
+        if (password != passwordConfirm) {
+            return ValidationResult.Error(R.string.validation_password_mismatch)
+        }
+
+        return ValidationResult.Success
+    }
+
+    // 일반 필드 검증 (이름, 지점, 직책 등)
+    fun validateNotEmpty(value: String, fieldName: String): ValidationResult {
+        if (value.isBlank()) {
+            return ValidationResult.ErrorWithArgs(R.string.validation_field_required, fieldName)
+        }
+        return ValidationResult.Success
+    }
+}
+
+// 검증 결과
+sealed class ValidationResult {
+    object Success : ValidationResult()
+    data class Error(val messageResId: Int) : ValidationResult()
+    data class ErrorWithArgs(val messageResId: Int, val args: Any) : ValidationResult()
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/sampoom/android/feature/auth/domain/model/User.kt b/app/src/main/java/com/sampoom/android/feature/auth/domain/model/User.kt
index b9e6e4b..d8479ae 100644
--- a/app/src/main/java/com/sampoom/android/feature/auth/domain/model/User.kt
+++ b/app/src/main/java/com/sampoom/android/feature/auth/domain/model/User.kt
@@ -1,8 +1,10 @@
 package com.sampoom.android.feature.auth.domain.model
 
 data class User(
-    val id: String,
+    val id: Long,
     val name: String,
-    val email: String,
-    val token: String
+    val role: String,
+    val accessToken: String,
+    val refreshToken: String,
+    val expiresIn: Int
 )
diff --git a/app/src/main/java/com/sampoom/android/feature/auth/domain/repository/AuthRepository.kt b/app/src/main/java/com/sampoom/android/feature/auth/domain/repository/AuthRepository.kt
index f5fccd8..747e985 100644
--- a/app/src/main/java/com/sampoom/android/feature/auth/domain/repository/AuthRepository.kt
+++ b/app/src/main/java/com/sampoom/android/feature/auth/domain/repository/AuthRepository.kt
@@ -3,6 +3,15 @@ package com.sampoom.android.feature.auth.domain.repository
 import com.sampoom.android.feature.auth.domain.model.User
 
 interface AuthRepository {
+    suspend fun signUp(
+        name: String,
+        workspace: String,
+        branch: String,
+        position: String,
+        email: String,
+        password: String
+    ): User
+
     suspend fun signIn(email: String, password: String): User
     suspend fun signOut()
     fun isSignedIn(): Boolean
diff --git a/app/src/main/java/com/sampoom/android/feature/auth/domain/usecase/SignInUseCase.kt b/app/src/main/java/com/sampoom/android/feature/auth/domain/usecase/LoginUseCase.kt
similarity index 78%
rename from app/src/main/java/com/sampoom/android/feature/auth/domain/usecase/SignInUseCase.kt
rename to app/src/main/java/com/sampoom/android/feature/auth/domain/usecase/LoginUseCase.kt
index 630b4e2..d31282c 100644
--- a/app/src/main/java/com/sampoom/android/feature/auth/domain/usecase/SignInUseCase.kt
+++ b/app/src/main/java/com/sampoom/android/feature/auth/domain/usecase/LoginUseCase.kt
@@ -4,8 +4,9 @@ import com.sampoom.android.feature.auth.domain.model.User
 import com.sampoom.android.feature.auth.domain.repository.AuthRepository
 import javax.inject.Inject
 
-class SignInUseCase @Inject constructor(
+class LoginUseCase @Inject constructor(
     private val repository: AuthRepository
 ) {
-    suspend operator fun invoke(email: String, password: String): User = repository.signIn(email, password)
+    suspend operator fun invoke(email: String, password: String): User =
+        repository.signIn(email, password)
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/sampoom/android/feature/auth/domain/usecase/SignUpUseCase.kt b/app/src/main/java/com/sampoom/android/feature/auth/domain/usecase/SignUpUseCase.kt
new file mode 100644
index 0000000..9fa4ddd
--- /dev/null
+++ b/app/src/main/java/com/sampoom/android/feature/auth/domain/usecase/SignUpUseCase.kt
@@ -0,0 +1,25 @@
+package com.sampoom.android.feature.auth.domain.usecase
+
+import com.sampoom.android.feature.auth.domain.model.User
+import com.sampoom.android.feature.auth.domain.repository.AuthRepository
+import javax.inject.Inject
+
+class SignUpUseCase @Inject constructor(
+    private val repository: AuthRepository
+) {
+    suspend operator fun invoke(
+        name: String,
+        workspace: String,
+        branch: String,
+        position: String,
+        email: String,
+        password: String
+    ): User = repository.signUp(
+        name = name,
+        workspace = workspace,
+        branch = branch,
+        position = position,
+        email = email,
+        password = password
+    )
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/sampoom/android/feature/auth/ui/LoginScreen.kt b/app/src/main/java/com/sampoom/android/feature/auth/ui/LoginScreen.kt
index 8efc1f6..36ed2a9 100644
--- a/app/src/main/java/com/sampoom/android/feature/auth/ui/LoginScreen.kt
+++ b/app/src/main/java/com/sampoom/android/feature/auth/ui/LoginScreen.kt
@@ -1,68 +1,170 @@
 package com.sampoom.android.feature.auth.ui
 
+import androidx.compose.foundation.Image
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.interaction.MutableInteractionSource
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.WindowInsets
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.ime
+import androidx.compose.foundation.layout.imePadding
 import androidx.compose.foundation.layout.padding
-import androidx.compose.material3.Button
+import androidx.compose.foundation.layout.wrapContentHeight
 import androidx.compose.material3.MaterialTheme
-import androidx.compose.material3.OutlinedTextField
 import androidx.compose.material3.Scaffold
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalFocusManager
+import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.res.stringResource
-import androidx.compose.ui.text.input.PasswordVisualTransformation
+import androidx.compose.ui.text.SpanStyle
+import androidx.compose.ui.text.buildAnnotatedString
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.text.style.TextDecoration
+import androidx.compose.ui.text.withStyle
 import androidx.compose.ui.unit.dp
 import androidx.hilt.lifecycle.viewmodel.compose.hiltViewModel
 import com.sampoom.android.R
+import com.sampoom.android.core.ui.component.CommonButton
+import com.sampoom.android.core.ui.component.CommonTextField
+import com.sampoom.android.core.ui.theme.Main500
+import com.sampoom.android.core.ui.component.ShowErrorSnackBar
+import com.sampoom.android.core.ui.component.rememberCommonSnackBarHostState
+import com.sampoom.android.core.ui.component.TopSnackBarHost
 
 @Composable
 fun LoginScreen(
     onSuccess: () -> Unit,
+    onNavigateSignUp: () -> Unit,
     viewModel: LoginViewModel = hiltViewModel()
 ) {
+    val emailLabel = stringResource(R.string.login_title_email)
+    val passwordLabel = stringResource(R.string.login_title_password)
+    val errorLabel = stringResource(R.string.common_error)
+
+    LaunchedEffect(emailLabel, passwordLabel, errorLabel) {
+        viewModel.bindLabel(emailLabel, passwordLabel, errorLabel)
+    }
+
     val state by viewModel.state.collectAsState()
 
-    if (state.success) onSuccess()
-    Scaffold { innerPadding ->
-        Column(
-            Modifier
+    LaunchedEffect(state.success) {
+        if (state.success) onSuccess()
+    }
+
+    val snackBarHostState = rememberCommonSnackBarHostState()
+    ShowErrorSnackBar(
+        errorMessage = state.error,
+        snackBarHostState = snackBarHostState,
+        onConsumed = { viewModel.consumeError() }
+    )
+    Scaffold(
+//        contentWindowInsets = WindowInsets.ime,
+//        snackbarHost = { CommonSnackBarHost(snackBarHostState) }
+    ) { innerPadding ->
+        val focusManager = LocalFocusManager.current
+        Box( // 터치 감지용 컨테이너
+            modifier = Modifier
                 .fillMaxSize()
-                .padding(innerPadding)
-                .padding(24.dp)
+                .clickable( // 빈 공간 터치 시 포커스 해제
+                    indication = null, // 터치 ripple 제거
+                    interactionSource = remember { MutableInteractionSource() }
+                ) {
+                    focusManager.clearFocus()
+                }
         ) {
-            Text(stringResource(R.string.login_title), style = MaterialTheme.typography.headlineMedium)
-            Spacer(Modifier.height(16.dp))
-            OutlinedTextField(
-                value = state.email,
-                onValueChange = { viewModel.onEvent(LoginUiEvent.EmailChanged(it)) },
-                label = { Text(stringResource(R.string.login_placeholder_email)) },
-                modifier = Modifier.fillMaxWidth()
-            )
-            Spacer(Modifier.height(8.dp))
-            OutlinedTextField(
-                value = state.password,
-                onValueChange = { viewModel.onEvent(LoginUiEvent.PasswordChanged(it)) },
-                label = { Text(stringResource(R.string.login_placeholder_password)) },
-                visualTransformation = PasswordVisualTransformation(),
-                modifier = Modifier.fillMaxWidth()
-            )
-            Spacer(Modifier.height(16.dp))
-            Button(
-                onClick = { viewModel.onEvent(LoginUiEvent.Submit) },
-                enabled = !state.loading,
-                modifier = Modifier.fillMaxWidth()
-            ) { Text(if (state.loading) stringResource(R.string.login_button_login_loading) else stringResource(R.string.login_button_login)) }
-
-            state.error?.let {
+            Column(
+                Modifier
+                    .fillMaxSize()
+                    .imePadding()
+                    .padding(innerPadding)
+                    .padding(16.dp),
+                horizontalAlignment = Alignment.CenterHorizontally,
+                verticalArrangement = Arrangement.Center
+            ) {
+                Spacer(Modifier.weight(1f))
+                Image(
+                    painter = painterResource(id = R.drawable.square_logo),
+                    contentDescription = stringResource(R.string.app_name)
+                )
+                Spacer(Modifier.height(48.dp))
+                CommonTextField(
+                    modifier = Modifier.fillMaxWidth(),
+                    value = state.email,
+                    onValueChange = { viewModel.onEvent(LoginUiEvent.EmailChanged(it)) },
+                    placeholder = stringResource(R.string.login_placeholder_email),
+                    isError = state.emailError != null,
+                    errorMessage = state.emailError
+                )
                 Spacer(Modifier.height(8.dp))
-                Text(it, color = MaterialTheme.colorScheme.error)
+                CommonTextField(
+                    modifier = Modifier.fillMaxWidth(),
+                    value = state.password,
+                    onValueChange = { viewModel.onEvent(LoginUiEvent.PasswordChanged(it)) },
+                    placeholder = stringResource(R.string.login_placeholder_password),
+                    isPassword = true,
+                    isError = state.passwordError != null,
+                    errorMessage = state.passwordError
+                )
+                Spacer(Modifier.height(48.dp))
+                CommonButton(
+                    onClick = { viewModel.onEvent(LoginUiEvent.Submit) },
+                    enabled = state.isValid && !state.loading,
+                    modifier = Modifier.fillMaxWidth()
+                ) {
+                    Text(
+                        if (state.loading) stringResource(R.string.login_button_login_loading)
+                        else stringResource(R.string.login_button_login)
+                    )
+                }
+
+
+                Spacer(Modifier.weight(1f))
+
+                val annotatedText = buildAnnotatedString {
+                    append(stringResource(R.string.login_need_account))
+
+                    // 클릭 가능한 회원가입 텍스트
+                    pushStringAnnotation(tag = "SIGNUP", annotation = "signup")
+                    withStyle(
+                        style = SpanStyle(
+                            color = Main500, // 원하는 색상
+                            textDecoration = TextDecoration.Underline
+                        )
+                    ) {
+                        append(stringResource(R.string.login_signup))
+                    }
+                    append(stringResource(R.string.login_do))
+                    pop()
+                }
+
+                Column(
+                    modifier = Modifier.fillMaxWidth(),
+                    horizontalAlignment = Alignment.CenterHorizontally
+                ) {
+                    Text(
+                        text = annotatedText,
+                        modifier = Modifier
+                            .padding(vertical = 24.dp)
+                            .clickable { onNavigateSignUp() },
+                        style = MaterialTheme.typography.bodyMedium.copy(textAlign = TextAlign.Center),
+                    )
+                }
+
+                // per-screen inline error removed in favor of snackbar
             }
         }
+        TopSnackBarHost(snackBarHostState, extraTopPadding = 16.dp)
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/sampoom/android/feature/auth/ui/LoginUiState.kt b/app/src/main/java/com/sampoom/android/feature/auth/ui/LoginUiState.kt
index dd36855..2546cab 100644
--- a/app/src/main/java/com/sampoom/android/feature/auth/ui/LoginUiState.kt
+++ b/app/src/main/java/com/sampoom/android/feature/auth/ui/LoginUiState.kt
@@ -3,7 +3,18 @@ package com.sampoom.android.feature.auth.ui
 data class LoginUiState(
     val email: String = "",
     val password: String = "",
+
+    // Error message
+    val emailError: String? = null,
+    val passwordError: String? = null,
+
     val loading: Boolean = false,
     val error: String? = null,
     val success: Boolean = false
-)
+) {
+    val isValid: Boolean
+        get() = email.isNotBlank() &&
+                password.isNotBlank() &&
+                emailError == null &&
+                passwordError == null
+}
diff --git a/app/src/main/java/com/sampoom/android/feature/auth/ui/LoginViewModel.kt b/app/src/main/java/com/sampoom/android/feature/auth/ui/LoginViewModel.kt
index c92c743..997312c 100644
--- a/app/src/main/java/com/sampoom/android/feature/auth/ui/LoginViewModel.kt
+++ b/app/src/main/java/com/sampoom/android/feature/auth/ui/LoginViewModel.kt
@@ -1,9 +1,13 @@
 package com.sampoom.android.feature.auth.ui
 
+import android.app.Application
 import android.util.Log
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
-import com.sampoom.android.feature.auth.domain.usecase.SignInUseCase
+import com.sampoom.android.feature.auth.domain.AuthValidator
+import com.sampoom.android.feature.auth.domain.ValidationResult
+import com.sampoom.android.feature.auth.domain.usecase.LoginUseCase
+import com.sampoom.android.core.network.serverMessageOrNull
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
@@ -13,23 +17,76 @@ import javax.inject.Inject
 
 @HiltViewModel
 class LoginViewModel @Inject constructor(
-    private val singIn: SignInUseCase
+    private val singIn: LoginUseCase,
+    private val application: Application
 ) : ViewModel() {
     private val _state = MutableStateFlow(LoginUiState())
     val state: StateFlow<LoginUiState> = _state
 
+    private var emailLabel: String = ""
+    private var passwordLabel: String = ""
+    private var errorLabel: String = ""
+
+    fun bindLabel(email: String, password: String, error: String) {
+        emailLabel = email
+        passwordLabel = password
+        errorLabel = error
+    }
+
     fun onEvent(e: LoginUiEvent) = when (e) {
-        is LoginUiEvent.EmailChanged -> _state.value = _state.value.copy(email = e.email)
-        is LoginUiEvent.PasswordChanged -> _state.value = _state.value.copy(password = e.password)
+        is LoginUiEvent.EmailChanged -> {
+            _state.value = _state.value.copy(email = e.email)
+            validateEmail()
+        }
+        is LoginUiEvent.PasswordChanged -> {
+            _state.value = _state.value.copy(password = e.password)
+            validatePassword()
+        }
         LoginUiEvent.Submit -> submit()
     }
 
+    private fun validateEmail() {
+        val result = AuthValidator.validateNotEmpty(_state.value.email, emailLabel)
+        _state.value = _state.value.copy(
+            emailError = result.toErrorMessage()
+        )
+    }
+
+    private fun validatePassword() {
+        val result = AuthValidator.validateNotEmpty(_state.value.password, passwordLabel)
+        _state.value = _state.value.copy(
+            passwordError = result.toErrorMessage()
+        )
+    }
+
+    private fun ValidationResult.toErrorMessage(): String? {
+        return when (this) {
+            is ValidationResult.Error -> application.getString(messageResId)
+            is ValidationResult.ErrorWithArgs -> application.getString(messageResId, args)
+            ValidationResult.Success -> null
+        }
+    }
+
     private fun submit() = viewModelScope.launch {
+        validateEmail()
+        validatePassword()
+
+        if (!_state.value.isValid) return@launch
+
         val s = _state.value
         _state.update { it.copy(loading = true, error = null) }
         runCatching { singIn(s.email, s.password) }
             .onSuccess { _state.update { it.copy(loading = false, success = true) } }
-            .onFailure { _state.update { it.copy(loading = false, error = it.error) } }
+            .onFailure { throwable ->
+                val backendMessage = throwable.serverMessageOrNull()
+                _state.update {
+                    it.copy(loading = false, error = backendMessage ?: (throwable.message ?: errorLabel))
+                }
+            }
         Log.d("LoginViewModel", "submit: ${_state.value}")
     }
+
+    fun consumeError() {
+        _state.update { it.copy(error = null) }
+    }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/sampoom/android/feature/auth/ui/SignUpScreen.kt b/app/src/main/java/com/sampoom/android/feature/auth/ui/SignUpScreen.kt
new file mode 100644
index 0000000..172037c
--- /dev/null
+++ b/app/src/main/java/com/sampoom/android/feature/auth/ui/SignUpScreen.kt
@@ -0,0 +1,212 @@
+package com.sampoom.android.feature.auth.ui
+
+import androidx.compose.foundation.Image
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.interaction.MutableInteractionSource
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.WindowInsets
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.ime
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Text
+import androidx.compose.material3.TopAppBar
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalFocusManager
+import androidx.compose.ui.res.painterResource
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import androidx.hilt.lifecycle.viewmodel.compose.hiltViewModel
+import com.sampoom.android.R
+import com.sampoom.android.core.ui.component.CommonButton
+import com.sampoom.android.core.ui.component.CommonTextField
+import com.sampoom.android.core.ui.component.ShowErrorSnackBar
+import com.sampoom.android.core.ui.component.rememberCommonSnackBarHostState
+import com.sampoom.android.core.ui.component.TopSnackBarHost
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun SignUpScreen(
+    onSuccess: () -> Unit,
+    onNavigateBack: () -> Unit = {},
+    viewModel: SignUpViewModel = hiltViewModel()
+) {
+    val nameLabel = stringResource(R.string.signup_title_name)
+    val branchLabel = stringResource(R.string.signup_title_branch)
+    val positionLabel = stringResource(R.string.signup_title_position)
+    val errorLabel = stringResource(R.string.common_error)
+
+    LaunchedEffect(nameLabel, branchLabel, positionLabel, errorLabel) {
+        viewModel.bindLabels(nameLabel, branchLabel, positionLabel, errorLabel)
+    }
+
+    val state by viewModel.state.collectAsState()
+    val labelTextSize = 16.sp
+
+    LaunchedEffect(state.success) {
+        if (state.success) onSuccess()
+    }
+
+    val snackBarHostState = rememberCommonSnackBarHostState()
+    ShowErrorSnackBar(
+        errorMessage = state.error,
+        snackBarHostState = snackBarHostState,
+        onConsumed = { viewModel.consumeError() }
+    )
+    Scaffold(
+        topBar = {
+            TopAppBar(
+                title = { Text("") },
+                navigationIcon = {
+                    IconButton(onClick = onNavigateBack) {
+                        Icon(
+                            painter = painterResource(id = R.drawable.ic_arrow_back),
+                            contentDescription = stringResource(R.string.nav_back)
+                        )
+                    }
+                }
+            )
+        },
+        contentWindowInsets = WindowInsets.ime,
+//        snackbarHost = { CommonSnackBarHost(snackBarHostState) }
+    ) { innerPadding ->
+        val focusManager = LocalFocusManager.current
+        Box( // 터치 감지용 컨테이너
+            modifier = Modifier
+                .fillMaxSize()
+                .clickable( // 빈 공간 터치 시 포커스 해제
+                    indication = null, // 터치 ripple 제거
+                    interactionSource = remember { MutableInteractionSource() }
+                ) {
+                    focusManager.clearFocus()
+                }
+        ) {
+            Column(
+                modifier = Modifier
+                    .fillMaxSize()
+                    .verticalScroll(rememberScrollState())
+                    .padding(innerPadding)
+                    .padding(16.dp),
+                horizontalAlignment = Alignment.Start,
+                verticalArrangement = Arrangement.Center
+            ) {
+                Image(
+                    painter = painterResource(id = R.drawable.oneline_logo),
+                    contentDescription = stringResource(R.string.app_name)
+                )
+                Spacer(Modifier.height(48.dp))
+                Text(
+                    text = stringResource(R.string.signup_title_name),
+                    fontSize = labelTextSize
+                )
+                CommonTextField(
+                    modifier = Modifier.fillMaxWidth(),
+                    value = state.name,
+                    onValueChange = { viewModel.onEvent(SignUpUiEvent.NameChanged(it)) },
+                    placeholder = stringResource(R.string.signup_placeholder_name),
+                    isError = state.nameError != null,
+                    errorMessage = state.nameError
+                )
+                Spacer(Modifier.height(8.dp))
+                Text(
+                    text = stringResource(R.string.signup_title_branch),
+                    fontSize = labelTextSize
+                )
+                CommonTextField(
+                    modifier = Modifier.fillMaxWidth(),
+                    value = state.branch,
+                    onValueChange = { viewModel.onEvent(SignUpUiEvent.BranchChanged(it)) },
+                    placeholder = stringResource(R.string.signup_placeholder_branch),
+                    isError = state.branchError != null,
+                    errorMessage = state.branchError
+                )
+                Spacer(Modifier.height(8.dp))
+                Text(
+                    text = stringResource(R.string.signup_title_position),
+                    fontSize = labelTextSize
+                )
+                CommonTextField(
+                    modifier = Modifier.fillMaxWidth(),
+                    value = state.position,
+                    onValueChange = { viewModel.onEvent(SignUpUiEvent.PositionChanged(it)) },
+                    placeholder = stringResource(R.string.signup_placeholder_position),
+                    isError = state.positionError != null,
+                    errorMessage = state.positionError
+                )
+                Spacer(Modifier.height(8.dp))
+                Text(
+                    text = stringResource(R.string.signup_title_email),
+                    fontSize = labelTextSize
+                )
+                CommonTextField(
+                    modifier = Modifier.fillMaxWidth(),
+                    value = state.email,
+                    onValueChange = { viewModel.onEvent(SignUpUiEvent.EmailChanged(it)) },
+                    placeholder = stringResource(R.string.signup_placeholder_email),
+                    isError = state.emailError != null,
+                    errorMessage = state.emailError
+                )
+                Spacer(Modifier.height(8.dp))
+                Text(
+                    text = stringResource(R.string.signup_title_password),
+                    fontSize = labelTextSize
+                )
+                CommonTextField(
+                    modifier = Modifier.fillMaxWidth(),
+                    value = state.password,
+                    onValueChange = { viewModel.onEvent(SignUpUiEvent.PasswordChanged(it)) },
+                    placeholder = stringResource(R.string.signup_placeholder_password),
+                    isPassword = true,
+                    isError = state.passwordError != null,
+                    errorMessage = state.passwordError
+                )
+                Spacer(Modifier.height(8.dp))
+                Text(
+                    text = stringResource(R.string.signup_title_password_check),
+                    fontSize = labelTextSize
+                )
+                CommonTextField(
+                    modifier = Modifier.fillMaxWidth(),
+                    value = state.passwordCheck,
+                    onValueChange = { viewModel.onEvent(SignUpUiEvent.PasswordCheckChanged(it)) },
+                    placeholder = stringResource(R.string.signup_placeholder_password_check),
+                    isPassword = true,
+                    isError = state.passwordCheckError != null,
+                    errorMessage = state.passwordCheckError
+                )
+                Spacer(Modifier.height(48.dp))
+                CommonButton(
+                    onClick = { viewModel.onEvent(SignUpUiEvent.Submit) },
+                    enabled = state.isValid && !state.loading,
+                    modifier = Modifier.fillMaxWidth(),
+                ) {
+                    Text(
+                        if (state.loading) stringResource(R.string.signup_button_signup_loading)
+                        else stringResource(R.string.signup_button_signup)
+                    )
+                }
+
+                // per-screen inline error removed in favor of snackbar
+            }
+        }
+        TopSnackBarHost(snackBarHostState, extraTopPadding = 16.dp)
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/sampoom/android/feature/auth/ui/SignUpUiEvent.kt b/app/src/main/java/com/sampoom/android/feature/auth/ui/SignUpUiEvent.kt
new file mode 100644
index 0000000..eb8e77b
--- /dev/null
+++ b/app/src/main/java/com/sampoom/android/feature/auth/ui/SignUpUiEvent.kt
@@ -0,0 +1,11 @@
+package com.sampoom.android.feature.auth.ui
+
+sealed interface SignUpUiEvent {
+    data class NameChanged(val name: String) : SignUpUiEvent
+    data class BranchChanged(val branch: String) : SignUpUiEvent
+    data class PositionChanged(val position: String) : SignUpUiEvent
+    data class EmailChanged(val email: String) : SignUpUiEvent
+    data class PasswordChanged(val password: String) : SignUpUiEvent
+    data class PasswordCheckChanged(val passwordCheck: String) : SignUpUiEvent
+    data object Submit: SignUpUiEvent
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/sampoom/android/feature/auth/ui/SignUpUiState.kt b/app/src/main/java/com/sampoom/android/feature/auth/ui/SignUpUiState.kt
new file mode 100644
index 0000000..524c1fe
--- /dev/null
+++ b/app/src/main/java/com/sampoom/android/feature/auth/ui/SignUpUiState.kt
@@ -0,0 +1,37 @@
+package com.sampoom.android.feature.auth.ui
+
+data class SignUpUiState(
+    val name: String = "",
+    val workspace: String = "대리점",
+    val branch: String = "",
+    val position: String = "",
+    val email: String = "",
+    val password: String = "",
+    val passwordCheck: String = "",
+
+    // Error message
+    val nameError: String? = null,
+    val branchError: String? = null,
+    val positionError: String? = null,
+    val emailError: String? = null,
+    val passwordError: String? = null,
+    val passwordCheckError: String? = null,
+
+    val loading: Boolean = false,
+    val error: String? = null,
+    val success: Boolean = false
+) {
+    val isValid: Boolean
+        get() = name.isNotBlank() &&
+                branch.isNotBlank() &&
+                position.isNotBlank() &&
+                email.isNotBlank() &&
+                password.isNotBlank() &&
+                passwordCheck.isNotBlank() &&
+                nameError == null &&
+                branchError == null &&
+                positionError == null &&
+                emailError == null &&
+                passwordError == null &&
+                passwordCheckError == null
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/sampoom/android/feature/auth/ui/SignUpViewModel.kt b/app/src/main/java/com/sampoom/android/feature/auth/ui/SignUpViewModel.kt
new file mode 100644
index 0000000..70e0f79
--- /dev/null
+++ b/app/src/main/java/com/sampoom/android/feature/auth/ui/SignUpViewModel.kt
@@ -0,0 +1,156 @@
+package com.sampoom.android.feature.auth.ui
+
+import android.app.Application
+import android.util.Log
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import com.sampoom.android.feature.auth.domain.AuthValidator
+import com.sampoom.android.feature.auth.domain.ValidationResult
+import com.sampoom.android.feature.auth.domain.usecase.SignUpUseCase
+import com.sampoom.android.core.network.serverMessageOrNull
+import dagger.hilt.android.lifecycle.HiltViewModel
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.update
+import kotlinx.coroutines.launch
+import javax.inject.Inject
+
+@HiltViewModel
+class SignUpViewModel @Inject constructor(
+    private val singUp: SignUpUseCase,
+    private val application: Application
+) : ViewModel() {
+    private val _state = MutableStateFlow(SignUpUiState())
+    val state: StateFlow<SignUpUiState> = _state
+
+    private var nameLabel: String = ""
+    private var branchLabel: String = ""
+    private var positionLabel: String = ""
+    private var errorLabel: String = ""
+
+    fun bindLabels(name: String, branch: String, position: String, error: String) {
+        nameLabel = name
+        branchLabel = branch
+        positionLabel = position
+        errorLabel = error
+    }
+
+    fun onEvent(e: SignUpUiEvent) = when (e) {
+        is SignUpUiEvent.NameChanged -> {
+            _state.value = _state.value.copy(name = e.name)
+            validateName()
+        }
+        is SignUpUiEvent.BranchChanged -> {
+            _state.value = _state.value.copy(branch = e.branch)
+            validateBranch()
+        }
+        is SignUpUiEvent.PositionChanged -> {
+            _state.value = _state.value.copy(position = e.position)
+            validatePosition()
+        }
+        is SignUpUiEvent.EmailChanged -> {
+            _state.value = _state.value.copy(email = e.email)
+            validateEmail()
+        }
+        is SignUpUiEvent.PasswordChanged -> {
+            _state.value = _state.value.copy(password = e.password)
+            validatePassword()
+            if (_state.value.passwordCheck.isNotBlank()) {
+                validatePasswordCheck()
+            } else {
+
+            }
+        }
+        is SignUpUiEvent.PasswordCheckChanged -> {
+            _state.value = _state.value.copy(passwordCheck = e.passwordCheck)
+            validatePasswordCheck()
+        }
+        SignUpUiEvent.Submit -> submit()
+    }
+
+    private fun validateName() {
+        val result = AuthValidator.validateNotEmpty(_state.value.name, nameLabel)
+        _state.value = _state.value.copy(
+            nameError = result.toErrorMessage()
+        )
+    }
+
+    private fun validateBranch() {
+        val result = AuthValidator.validateNotEmpty(_state.value.branch, branchLabel)
+        _state.value = _state.value.copy(
+            branchError = result.toErrorMessage()
+        )
+    }
+
+    private fun validatePosition() {
+        val result = AuthValidator.validateNotEmpty(_state.value.position, positionLabel)
+        _state.value = _state.value.copy(
+            positionError = result.toErrorMessage()
+        )
+    }
+
+    private fun validateEmail() {
+        val result = AuthValidator.validateEmail(_state.value.email)
+        _state.value = _state.value.copy(
+            emailError = result.toErrorMessage()
+        )
+    }
+
+    private fun validatePassword() {
+        val result = AuthValidator.validatePassword(_state.value.password)
+        _state.value = _state.value.copy(
+            passwordError = result.toErrorMessage()
+        )
+    }
+
+    private fun validatePasswordCheck() {
+        val result = AuthValidator.validatePasswordCheck(_state.value.password, _state.value.passwordCheck)
+        _state.value = _state.value.copy(
+            passwordCheckError = result.toErrorMessage()
+        )
+    }
+
+    private fun ValidationResult.toErrorMessage(): String? {
+        return when (this) {
+            is ValidationResult.Error -> application.getString(messageResId)
+            is ValidationResult.ErrorWithArgs -> application.getString(messageResId, args)
+            ValidationResult.Success -> null
+        }
+    }
+
+    private fun submit() = viewModelScope.launch {
+        validateName()
+        validateBranch()
+        validatePosition()
+        validateEmail()
+        validatePassword()
+        validatePasswordCheck()
+
+        if (!_state.value.isValid) return@launch
+
+        val s = _state.value
+        _state.update { it.copy(loading = true, error = null) }
+        runCatching {
+            singUp(
+                name = s.name,
+                workspace = s.workspace,
+                branch = s.branch,
+                position = s.position,
+                email = s.email,
+                password = s.password
+            )
+        }
+            .onSuccess { _state.update { it.copy(loading = false, success = true) } }
+            .onFailure { throwable ->
+                val backendMessage = throwable.serverMessageOrNull()
+                _state.update {
+                    it.copy(loading = false, error = backendMessage ?: (throwable.message ?: errorLabel))
+                }
+            }
+        Log.d("SignUpViewModel", "submit: ${_state.value}")
+    }
+
+    fun consumeError() {
+        _state.update { it.copy(error = null) }
+    }
+}
diff --git a/app/src/main/res/drawable/ic_arrow_back.xml b/app/src/main/res/drawable/ic_arrow_back.xml
new file mode 100644
index 0000000..27ea91f
--- /dev/null
+++ b/app/src/main/res/drawable/ic_arrow_back.xml
@@ -0,0 +1,5 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android" android:autoMirrored="true" android:height="24dp" android:tint="#000000" android:viewportHeight="960" android:viewportWidth="960" android:width="24dp">
+      
+    <path android:fillColor="@color/text" android:pathData="M313,520L537,744L480,800L160,480L480,160L537,216L313,440L800,440L800,520L313,520Z"/>
+    
+</vector>
diff --git a/app/src/main/res/drawable/oneline_logo.xml b/app/src/main/res/drawable/oneline_logo.xml
new file mode 100644
index 0000000..fc8400c
--- /dev/null
+++ b/app/src/main/res/drawable/oneline_logo.xml
@@ -0,0 +1,12 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="120dp"
+    android:height="29dp"
+    android:viewportWidth="120"
+    android:viewportHeight="29">
+  <path
+      android:pathData="M1.81,0.87H26.22V4.81H1.81V0.87ZM4.02,11.18H23.66V15.08H4.02V11.18ZM0.02,22.02H27.92V25.93H0.02V22.02Z"
+      android:fillColor="#8080FF"/>
+  <path
+      android:pathData="M57.81,7.91V11.98H32.98V7.91H37.17V5.06H33.26V1H57.52V5.06H53.62V7.91H57.81ZM42.54,5.06V7.91H48.24V5.06H42.54ZM59.22,17.32H48.08V18.76H57.62V28.33H33.17V18.76H42.7V17.32H31.57V13.22H59.22V17.32ZM52.27,24.36V22.73H38.51V24.36H52.27ZM88.08,7.08H91.21V12.17H88.08V21.7H82.67V1H88.08V7.08ZM74.06,11.62V5.77H63.37V1.19H79.44V11.62H74.06ZM81.1,16.81C79.41,17.54 76.65,17.8 73.93,17.8H62.35V13.29H66.13V8.23H71.47V13.29H74.03C76.56,13.29 79.41,13.03 81.1,12.3V16.81ZM69.42,19.72V23.72H88.46V28.33H63.95V19.72H69.42ZM119.56,1V28.33H114.15V1H119.56ZM110.19,1.64V16.68H99.72V22.18H105.64C108.24,22.18 111.05,21.64 112.71,20.87V25.74C111.05,26.57 108.14,27.05 105.42,27.05H94.35V11.88H104.81V6.5H94.28V1.64H110.19Z"
+      android:fillColor="@color/text"/>
+</vector>
diff --git a/app/src/main/res/drawable/outline_close.xml b/app/src/main/res/drawable/outline_close.xml
new file mode 100644
index 0000000..dc414f5
--- /dev/null
+++ b/app/src/main/res/drawable/outline_close.xml
@@ -0,0 +1,5 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android" android:height="24dp" android:viewportHeight="960" android:viewportWidth="960" android:width="24dp">
+      
+    <path android:fillColor="@color/text" android:pathData="M256,760L200,704L424,480L200,256L256,200L480,424L704,200L760,256L536,480L760,704L704,760L480,536L256,760Z"/>
+    
+</vector>
diff --git a/app/src/main/res/drawable/square_logo.xml b/app/src/main/res/drawable/square_logo.xml
new file mode 100644
index 0000000..ebe4e94
--- /dev/null
+++ b/app/src/main/res/drawable/square_logo.xml
@@ -0,0 +1,12 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="113dp"
+    android:height="113dp"
+    android:viewportWidth="113"
+    android:viewportHeight="113">
+  <path
+      android:pathData="M4.64,0.76H50.42V8.14H4.64V0.76ZM8.78,20.08H45.62V27.4H8.78V20.08ZM1.28,40.42H53.6V47.74H1.28V40.42Z"
+      android:fillColor="#8080FF"/>
+  <path
+      android:pathData="M109.64,13.96V21.58H63.08V13.96H70.94V8.62H63.62V1H109.1V8.62H101.78V13.96H109.64ZM81.02,8.62V13.96H91.7V8.62H81.02ZM112.28,31.6H91.4V34.3H109.28V52.24H63.44V34.3H81.32V31.6H60.44V23.92H112.28V31.6ZM99.26,44.8V41.74H73.46V44.8H99.26ZM48.68,72.4H54.56V81.94H48.68V99.82H38.54V61H48.68V72.4ZM22.4,80.92V69.94H2.36V61.36H32.48V80.92H22.4ZM35.6,90.64C32.42,92.02 27.26,92.5 22.16,92.5H0.44V84.04H7.52V74.56H17.54V84.04H22.34C27.08,84.04 32.42,83.56 35.6,82.18V90.64ZM13.7,96.1V103.6H49.4V112.24H3.44V96.1H13.7ZM107.71,61V112.24H97.57V61H107.71ZM90.13,62.2V90.4H70.51V100.72H81.61C86.47,100.72 91.75,99.7 94.87,98.26V107.38C91.75,108.94 86.29,109.84 81.19,109.84H60.43V81.4H80.05V71.32H60.31V62.2H90.13Z"
+      android:fillColor="@color/text"/>
+</vector>
diff --git a/app/src/main/res/font/gmarket_sans_bold.otf b/app/src/main/res/font/gmarket_sans_bold.otf
new file mode 100644
index 0000000..3a7ab60
Binary files /dev/null and b/app/src/main/res/font/gmarket_sans_bold.otf differ
diff --git a/app/src/main/res/font/gmarket_sans_light.otf b/app/src/main/res/font/gmarket_sans_light.otf
new file mode 100644
index 0000000..c588d3e
Binary files /dev/null and b/app/src/main/res/font/gmarket_sans_light.otf differ
diff --git a/app/src/main/res/font/gmarket_sans_medium.otf b/app/src/main/res/font/gmarket_sans_medium.otf
new file mode 100644
index 0000000..af2cfc3
Binary files /dev/null and b/app/src/main/res/font/gmarket_sans_medium.otf differ
diff --git a/app/src/main/res/values-night/colors.xml b/app/src/main/res/values-night/colors.xml
index f8c6127..b2196f0 100644
--- a/app/src/main/res/values-night/colors.xml
+++ b/app/src/main/res/values-night/colors.xml
@@ -1,10 +1,28 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
-    <color name="purple_200">#FFBB86FC</color>
-    <color name="purple_500">#FF6200EE</color>
-    <color name="purple_700">#FF3700B3</color>
-    <color name="teal_200">#FF03DAC5</color>
-    <color name="teal_700">#FF018786</color>
     <color name="black">#FF000000</color>
     <color name="white">#FFFFFFFF</color>
+
+    <color name="success_green">#10B981</color>
+    <color name="fail_red">#FF6C6C</color>
+    <color name="wait_yellow">#F59E0B</color>
+
+    <color name="grey_400">#444444</color>
+    <color name="grey_300">#7C7C7C</color>
+    <color name="grey_200">#CCCCCC</color>
+    <color name="grey_100">#E9EAEC</color>
+
+    <color name="main_900">#1F1F5C</color>
+    <color name="main_800">#333399</color>
+    <color name="main_700">#4C4CBB</color>
+    <color name="main_600">#6666DD</color>
+    <color name="main_500">#8080FF</color>
+    <color name="main_400">#9999FF</color>
+    <color name="main_300">#B3B3FF</color>
+    <color name="main_200">#CCCCFF</color>
+    <color name="main_100">#E6E6FF</color>
+
+    <color name="background">#17181B</color>
+    <color name="background_card">#36393F</color>
+    <color name="text">#FFFFFF</color>
 </resources>
\ No newline at end of file
diff --git a/app/src/main/res/values/colors.xml b/app/src/main/res/values/colors.xml
index f8c6127..1af7af7 100644
--- a/app/src/main/res/values/colors.xml
+++ b/app/src/main/res/values/colors.xml
@@ -1,10 +1,28 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
-    <color name="purple_200">#FFBB86FC</color>
-    <color name="purple_500">#FF6200EE</color>
-    <color name="purple_700">#FF3700B3</color>
-    <color name="teal_200">#FF03DAC5</color>
-    <color name="teal_700">#FF018786</color>
     <color name="black">#FF000000</color>
     <color name="white">#FFFFFFFF</color>
+
+    <color name="success_green">#10B981</color>
+    <color name="fail_red">#FF6C6C</color>
+    <color name="wait_yellow">#F59E0B</color>
+
+    <color name="grey_400">#444444</color>
+    <color name="grey_300">#7C7C7C</color>
+    <color name="grey_200">#CCCCCC</color>
+    <color name="grey_100">#E9EAEC</color>
+
+    <color name="main_900">#1F1F5C</color>
+    <color name="main_800">#333399</color>
+    <color name="main_700">#4C4CBB</color>
+    <color name="main_600">#6666DD</color>
+    <color name="main_500">#8080FF</color>
+    <color name="main_400">#9999FF</color>
+    <color name="main_300">#B3B3FF</color>
+    <color name="main_200">#CCCCFF</color>
+    <color name="main_100">#E6E6FF</color>
+
+    <color name="background">#F5F5F5</color>
+    <color name="background_card">#FFFFFF</color>
+    <color name="text">#36393F</color>
 </resources>
\ No newline at end of file
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 8a5d69e..5de1348 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -2,6 +2,7 @@
     <string name="app_name">삼품관리</string>
 
     <!-- Navigation Bar -->
+    <string name="nav_back">뒤로가기</string>
     <string name="nav_dashboard">대시보드</string>
     <string name="nav_delivery">출고목록</string>
     <string name="nav_cart">장바구니</string>
@@ -9,10 +10,32 @@
 
     <!-- 로그인 -->
     <string name="login_title">로그인</string>
-    <string name="login_placeholder_email">이메일</string>
-    <string name="login_placeholder_password">비밀번호</string>
+    <string name="login_title_email">이메일</string>
+    <string name="login_title_password">비밀번호</string>
+    <string name="login_placeholder_email">이메일 입력</string>
+    <string name="login_placeholder_password">비밀번호 입력</string>
     <string name="login_button_login">로그인</string>
     <string name="login_button_login_loading">로그인 중…</string>
+    <string name="login_need_account">계정이 없으신가요?</string>
+    <string name="login_signup">회원가입</string>
+    <string name="login_do">하기</string>
+
+    <!-- 회원가입 -->
+    <string name="signup_title">회원가입</string>
+    <string name="signup_title_name">이름</string>
+    <string name="signup_title_branch">지점</string>
+    <string name="signup_title_position">직급</string>
+    <string name="signup_title_email">이메일</string>
+    <string name="signup_title_password">비밀번호</string>
+    <string name="signup_title_password_check">비밀번호 확인</string>
+    <string name="signup_placeholder_name">이름 입력</string>
+    <string name="signup_placeholder_branch">지점 선택</string>
+    <string name="signup_placeholder_position">직급 선택</string>
+    <string name="signup_placeholder_email">이메일 입력</string>
+    <string name="signup_placeholder_password">비밀번호 입력</string>
+    <string name="signup_placeholder_password_check">비밀번호 입력 확인</string>
+    <string name="signup_button_signup">회원가입</string>
+    <string name="signup_button_signup_loading">회원 가입 중…</string>
 
     <!-- 부품 목록 -->
     <string name="part_title">부품 목록</string>
@@ -21,4 +44,16 @@
     <!-- Common -->
     <string name="common_error">오류가 발생했습니다</string>
     <string name="common_retry">다시 시도</string>
+    <string name="common_close">닫기</string>
+
+    <!-- Validation -->
+    <string name="validation_email_required">이메일을 입력해주세요</string>
+    <string name="validation_email_invalid">올바른 이메일 형식이 아닙니다</string>
+    <string name="validation_password_required">비밀번호를 입력해주세요</string>
+    <string name="validation_password_min_length">비밀번호는 최소 8자 이상이어야 합니다</string>
+    <string name="validation_password_max_length">비밀번호는 최대 30자까지 가능합니다</string>
+    <string name="validation_password_complexity">영문, 숫자, 특수문자를 각각 1개 이상 포함해야 합니다</string>
+    <string name="validation_password_confirm_required">비밀번호 확인을 입력해주세요</string>
+    <string name="validation_password_mismatch">비밀번호가 일치하지 않습니다</string>
+    <string name="validation_field_required">%s을(를) 입력해주세요</string>
 </resources>
\ No newline at end of file
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 3c44195..3d5c222 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -1,6 +1,7 @@
 [versions]
 agp = "8.13.0"
 coreSplashscreen = "1.0.1"
+datastorePreferences = "1.1.7"
 hiltAndroid = "2.57.2"
 hiltNavigationCompose = "1.3.0"
 kotlin = "2.2.20"
@@ -11,6 +12,7 @@ espressoCore = "3.7.0"
 lifecycleRuntimeKtx = "2.9.4"
 activityCompose = "1.11.0"
 composeBom = "2025.10.00"
+loggingInterceptor = "5.2.1"
 material = "1.9.3"
 materialIconsCore = "1.7.8"
 navigationCompose = "2.9.5"
@@ -19,6 +21,7 @@ retrofitVersion = "3.0.0"
 [libraries]
 androidx-core-ktx = { group = "androidx.core", name = "core-ktx", version.ref = "coreKtx" }
 androidx-core-splashscreen = { module = "androidx.core:core-splashscreen", version.ref = "coreSplashscreen" }
+androidx-datastore-preferences = { module = "androidx.datastore:datastore-preferences", version.ref = "datastorePreferences" }
 androidx-hilt-lifecycle-viewmodel-compose = { module = "androidx.hilt:hilt-lifecycle-viewmodel-compose", version.ref = "hiltNavigationCompose" }
 androidx-hilt-navigation-compose = { module = "androidx.hilt:hilt-navigation-compose", version.ref = "hiltNavigationCompose" }
 androidx-navigation-compose = { module = "androidx.navigation:navigation-compose", version.ref = "navigationCompose" }
@@ -41,6 +44,7 @@ androidx-compose-ui-tooling-preview = { group = "androidx.compose.ui", name = "u
 androidx-compose-ui-test-manifest = { group = "androidx.compose.ui", name = "ui-test-manifest" }
 androidx-compose-ui-test-junit4 = { group = "androidx.compose.ui", name = "ui-test-junit4" }
 androidx-compose-material3 = { group = "androidx.compose.material3", name = "material3" }
+logging-interceptor = { module = "com.squareup.okhttp3:logging-interceptor", version.ref = "loggingInterceptor" }
 retrofit = { module = "com.squareup.retrofit2:retrofit", version.ref = "retrofitVersion" }
 
 [plugins]