diff --git a/app/api/student/resume/confirm/helpers.ts b/app/api/student/resume/confirm/helpers.ts
new file mode 100644
index 000000000..e69de29bb
diff --git a/app/api/student/resume/confirm/route.timezone-boundaries.test.ts b/app/api/student/resume/confirm/route.timezone-boundaries.test.ts
new file mode 100644
index 000000000..648dac603
--- /dev/null
+++ b/app/api/student/resume/confirm/route.timezone-boundaries.test.ts
@@ -0,0 +1,39 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
+import { normalizeTimezone, formatDateForLocale, isValidDate, handleDST } from './route';
+
+describe('ApiStudentResumeConfirmRoute - Timezone Normalization & Calendar Data Boundary Alignment', () => {
+  beforeEach(() => vi.resetAllMocks());
+  afterEach(() => vi.clearAllMocks());
+
+  it('should normalize timestamps across UTC, EST, IST, JST', () => {
+    const ts = '2026-07-10T23:30:00Z';
+    expect(normalizeTimezone(ts, 'UTC')).toBe('2026-07-10');
+    expect(normalizeTimezone(ts, 'IST')).toBe('2026-07-11');
+    expect(normalizeTimezone(ts, 'JST')).toBe('2026-07-11');
+  });
+
+  it('should align activity blocks across date boundaries', () => {
+    const timestamps = ['2026-07-10T23:59:00Z', '2026-07-11T00:01:00Z'];
+    const results = timestamps.map((t) => normalizeTimezone(t, 'IST'));
+    expect(results[0]).toBe('2026-07-11');
+    expect(results[1]).toBe('2026-07-11');
+  });
+
+  it('should handle leap year dates correctly', () => {
+    expect(isValidDate('2024-02-29T12:00:00Z')).toBe(true);
+    expect(isValidDate('2025-02-29T12:00:00Z')).toBe(false);
+  });
+
+  it('should handle DST transitions', () => {
+    const spring = '2024-03-10T02:30:00-05:00';
+    const fall = '2024-11-03T01:30:00-04:00';
+    expect(handleDST(spring)).toBeDefined();
+    expect(handleDST(fall)).toBeDefined();
+  });
+
+  it('should format dates for different locales', () => {
+    const date = '2026-07-10T12:00:00Z';
+    expect(formatDateForLocale(date, 'en-US')).toMatch(/\d{2}\/\d{2}\/\d{4}/);
+    expect(formatDateForLocale(date, 'en-GB')).toMatch(/\d{2}\/\d{2}\/\d{4}/);
+  });
+});
diff --git a/lib/svg/themes.ts b/lib/svg/themes.ts
index 99b56f451..f71b1590e 100644
--- a/lib/svg/themes.ts
+++ b/lib/svg/themes.ts
@@ -2,15 +2,40 @@ import { z } from 'zod';
 import { BadgeTheme } from '../../types';
 import { hexColor } from './sanitizer';
 
+// Helper to sanitize hex colors (strip # prefix)
+export function sanitizeHexColor(value: string): string {
+  return value.replace(/^#/, '').trim();
+}
+
+// Updated regex for validation (without #)
 const HEX_COLOR_REGEX = /^[0-9a-fA-F]{3,4}$|^[0-9a-fA-F]{6,8}$/;
 
 export const badgeThemeSchema = z.object({
-  bg: z.string().regex(HEX_COLOR_REGEX, { message: 'Invalid bg color format' }),
-  text: z.string().regex(HEX_COLOR_REGEX, { message: 'Invalid text color format' }),
-  accent: z.string().regex(HEX_COLOR_REGEX, { message: 'Invalid accent color format' }),
+  bg: z
+    .string()
+    .transform(sanitizeHexColor)
+    .refine((val) => HEX_COLOR_REGEX.test(val), {
+      message: 'Invalid bg color format - must be a valid hex color (e.g., ffffff or #ffffff)',
+    }),
+  text: z
+    .string()
+    .transform(sanitizeHexColor)
+    .refine((val) => HEX_COLOR_REGEX.test(val), {
+      message: 'Invalid text color format - must be a valid hex color (e.g., ffffff or #ffffff)',
+    }),
+  accent: z
+    .string()
+    .transform(sanitizeHexColor)
+    .refine((val) => HEX_COLOR_REGEX.test(val), {
+      message: 'Invalid accent color format - must be a valid hex color (e.g., ffffff or #ffffff)',
+    }),
   negative: z
     .string()
-    .regex(HEX_COLOR_REGEX, { message: 'Invalid negative color format' })
+    .transform(sanitizeHexColor)
+    .refine((val) => HEX_COLOR_REGEX.test(val), {
+      message:
+        'Invalid negative color format - must be a valid hex color (e.g., ffffff or #ffffff)',
+    })
     .optional(),
 });
 
@@ -64,26 +89,20 @@ export const themes: Record<string, BadgeTheme> = {
   monokai: makeTheme('272822', 'f8f8f2', 'a6e22e', 'f92672'),
   midnight_ocean: makeTheme('020c1b', 'ccd6f6', '0af5ff', 'ff4d6d'),
   enterprise: makeTheme('1a1a2e', 'e2e8f0', '6366f1', '8b5cf6'),
-  // India theme — saffron accent (#FF9933), India green negative (#138808)
   india: makeTheme('0a0a0a', 'ffffff', 'FF9933', '138808'),
 };
 
-// Auto-theme pairs: the SVG switches between these two palettes
-// using @media (prefers-color-scheme) so the badge adapts to the
-// viewer's OS-level light/dark setting without any JavaScript.
+// Auto-theme pairs
 export const AUTO_THEME_LIGHT: BadgeTheme = themes.light ?? themes.default;
 export const AUTO_THEME_DARK: BadgeTheme = themes.dark ?? themes.default;
 
 /**
- * Resolves a theme case-insensitively by matching the normalized user input
- * against the normalized theme registry keys. Returns the standard theme key.
+ * Resolves a theme case-insensitively
  */
 export function getNormalizedThemeKey(themeInput: string | undefined | null): string {
-  if (!themeInput) return 'default'; // fallback key
-
+  if (!themeInput) return 'default';
   const target = themeInput.trim().toLowerCase();
   const matchedKey = Object.keys(themes).find((key) => key.toLowerCase() === target);
-
   return matchedKey || 'default';
 }