index.css

body {
    background-image: linear-gradient(#5a5a5a, #00e7ff);
    height: 94.5vh;
}

main {
    margin: auto;
    width: 100%;
}

h1 {
    font-size: 3rem;
    font-family: 'Courier New', Courier, monospace;
    color: white;
}

div#rule p{
    font-size: 1.5rem;
    font-family: 'Courier New', Courier, monospace;
    margin: 0.25rem auto;
    color: white;
}

p#sample-text {
    font-size: 1.25rem;
    background-color: #fff;
    color: rgba(0, 0, 0, 0.65);
    padding: 1rem;
    margin: 2rem auto;
    width: fit-content;
    border-radius: 0.5rem 1rem 0.5rem 1rem;
    border: 2px dashed #000;
}

#timer-sectn {
    position: absolute;
    top: 25rem;
    right: 10rem;
    font-size: 1.5rem;
    background: white;
    border: 1px solid;
    border-radius: 50%;
    padding: 1.5rem;
}

@media screen and (min-width: 1175px) {
    #timer-sectn {
        right: 2.5rem;
    }
}

@media screen and (max-width: 1174px) {
    #timer-sectn {
        top: 4rem;
        right: 2.5rem;
    }
}

#timer-sectn h2 {
    margin: 0 0 0.45rem 0;
    text-decoration: underline;
    text-decoration-skip-ink: none;
}

#timer {
    margin: 0;
    font-size: 1.75rem;
    font-weight: bold;
}

section {
    margin: auto;
    width: 100%;
    text-align: center;
}

#countdown {
    /* display: none; */
    position: absolute;
    top: 17rem;
    left: 0;
    right: 0;
    font-size: 18rem;
    font-weight: bold;
    color: rgb(98, 98, 98, 0.75);
    animation: cntdwn 1s linear 0.1s infinite;
}

@keyframes cntdwn {
    0% {
        transform: scale(1);
    }
    15% {
        transform: scale(0.9);
    }
    25% {
        transform: scale(0.8);
    }
    40% {
        transform: scale(0.65);
    }
    50% {
        transform: scale(0.5);
    }
    60% {
        transform: scale(0.4);
    }
    75% {
        transform: scale(0.3);
    } 
    100% {
        transform: scale(0.1);
    }
}

textarea {
    font-size: 1.25rem;
    padding: 1.25rem;
    background-color: rgba(255, 255, 255, 0.75);
    border: 0.125rem solid rgba(0, 0, 0, 0.5);
    border-radius: 0.25rem;
    outline: 0.45rem solid rgb(0, 0, 0);
    resize: none;
    color: black;
    font-weight: 600;
}

.error-text {
    outline: 0.45rem groove red;
    background-color: rgba(255, 0, 0, 0.25);
}

.success-text {
    outline: 0.45rem groove green;
    background-color: rgba(0, 255, 0, 0.25);
}

button {
    display: inline-block;
    padding: 1rem;
    margin: 2rem 1.5rem;
    background-color: black;
    color: white;
    border: 0.125rem solid gray;
    border-radius: 0.5rem;
    font-size: 1.5rem;
    font-weight: bold;
    font-style: italic;
    transition: all 0.1s;
}

button#reset {
    background-color: white;
    color: black;;    
}

button:hover {
    cursor: pointer;
    box-shadow: 0px 0px 10px rgba(0, 0, 0, 0.25);
    transform: scale(1.03);
}

button#reset:hover {
    cursor: pointer;
    box-shadow: 0px 0px 10px rgba(0, 0, 0, 0.125);
    transform: none;
}

button:disabled {
    background-color: #ccc;
    color: #333;
    border: 0.125rem solid #ccc;
    box-shadow: none;
}

button:disabled:hover {
    cursor: default;
    transform: none;
}