body {
    background: #f4f6f9;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
}

.form-container {
    max-width: 1200px;
    margin: 30px auto;
    background: white;
    border-radius: 0.5rem;
    box-shadow: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
    overflow: hidden;
}

.form-header {
    background: #003366;
    color: white;
    padding: 1.25rem 1.5rem;
    text-align: center;
}

.form-header h1 {
    margin: 0;
    font-size: 1.5rem;
    font-weight: 600;
}

.form-header .badge {
    margin-top: 0.5rem;
}

.form-body {
    padding: 2rem 1.5rem;
}

.section-title {
    font-size: 0.8rem;
    font-weight: 700;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: #6c757d;
    border-bottom: 1px solid #dee2e6;
    padding-bottom: 0.35rem;
    margin: 1.5rem 0 1rem 0;
}

.section-title:first-child {
    margin-top: 0;
}

.required {
    color: #dc3545;
}

.form-control.is-invalid,
.form-check-input.is-invalid {
    border-color: #dc3545;
}

.invalid-feedback {
    display: block;
    color: #dc3545;
    font-size: 0.875rem;
    margin-top: 0.25rem;
}

.alert {
    margin-bottom: 1.5rem;
}

.asignaturas-grid {
    display: grid;
    grid-template-columns: repeat(6, 1fr);
    gap: 1rem;
    margin-bottom: 1rem;
}

@media (max-width: 992px) {
    .asignaturas-grid { grid-template-columns: repeat(3, 1fr); }
}

@media (max-width: 576px) {
    .asignaturas-grid { grid-template-columns: repeat(2, 1fr); }
}

.form-check-asignatura {
    padding: 0.75rem;
    border: 1px solid #dee2e6;
    border-radius: 0.25rem;
    transition: all 0.2s ease;
}

.form-check-asignatura:hover {
    background-color: #f8f9fa;
    border-color: #0d6efd;
}

.asignaturas-grid.asig-invalid .form-check-asignatura {
    border-color: #dc3545;
    background-color: #fff5f5;
}

.asignaturas-grid.asig-invalid .form-check-label {
    color: #dc3545;
}

.form-check-asignatura .form-check-input:checked ~ .form-check-label {
    font-weight: 600;
    color: #0d6efd;
}

.btn-submit {
    width: 100%;
    padding: 0.75rem;
    font-size: 1rem;
    font-weight: 600;
    margin-top: 1.5rem;
}

.footer-text {
    font-size: 0.875rem;
    color: #6c757d;
    text-align: center;
    margin-top: 1.5rem;
    border-top: 1px solid #dee2e6;
    padding-top: 1rem;
}