:root {
    --navy: #0D1B2A;
    --lime: #A4FF00;
    --mint: #B2F2BB;
    --gray: #F1F3F5;
    --white: #FFFFFF;
}

body {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    background-color: var(--navy);
    color: var(--white);
    margin: 0;
    font-family: 'Segoe UI', sans-serif;
}

main {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 2rem;
}

.code-box {
    background-color: var(--gray);
    padding: 3rem 2rem;
    border-radius: 20px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.3);
    width: 100%;
    max-width: 400px;
    animation: fadeIn 1s ease-out;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to   { opacity: 1; transform: translateY(0); }
}

.logo {
    max-height: 60px;
    margin-bottom: 20px;
}

h1 {
    color: var(--navy);
    font-weight: bold;
    font-size: 1.75rem;
    margin-bottom: 1.5rem;
}

.form-control {
    font-size: 2rem;
    text-align: center;
    border: 2px solid var(--lime);
    border-radius: 12px;
    padding: 1rem;
    color: #000;
    background-color: #fff;
    transition: all 0.3s ease;
}

.form-control:focus {
    border-color: var(--mint);
    box-shadow: 0 0 10px var(--mint);
    outline: none;
}

.form-control::placeholder {
    color: #999;
    letter-spacing: 0.5rem;
}

.btn-lime {
    background-color: var(--lime);
    color: var(--navy);
    font-weight: bold;
    border: none;
    font-size: 1.25rem;
    padding: 0.75rem;
    border-radius: 12px;
    transition: background-color 0.3s ease;
}

.btn-lime:hover {
    background-color: var(--mint);
    color: var(--navy);
}

.teacherLinkLogin{
    text-decoration: none;
    color: grey;
}

.teacherLinkLogin:hover,.teacherLinkLogin:focus,.teacherLinkLogin:active{
    color: #0D1B2A;
}

@media (max-width: 576px) {
    .form-control {
        font-size: 1.5rem;
    }
    h1 {
        font-size: 1.5rem;
    }
}  

.greyCopy{
    bottom: 5px !important;
}