/* Estilos específicos para contenidos.html */
.main-content {
    padding: 2rem 0;
    text-align: center;
}

.periodos-buttons {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.periodo-card {
    background: white;
    border-radius: 15px;
    padding: 2rem;
    box-shadow: 0 8px 25px rgba(0,0,0,0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    text-align: center;
    border-left: 5px solid #dc3545;
}

.periodo-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 35px rgba(0,0,0,0.15);
}

.periodo-card h3 {
    color: #dc3545;
    margin-bottom: 0.5rem;
    font-size: 1.5rem;
    font-weight: 700;
}

.periodo-card p {
    color: #666;
    margin-bottom: 1.5rem;
    font-size: 1rem;
}

.periodo-btn {
    display: inline-block;
    background: #dc3545;
    color: white;
    padding: 0.8em 2em;
    border-radius: 2em;
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s ease;
    border: 2px solid #dc3545;
}

.periodo-btn:hover {
    background: white;
    color: #dc3545;
    transform: translateY(-2px);
}

.back-btn {
    display: inline-block;
    background: #007bff;
    color: white;
    padding: 0.8em 2em;
    border-radius: 2em;
    text-decoration: none;
    margin-top: 2rem;
    transition: background 0.3s ease;
}

.back-btn:hover {
    background: #0056b3;
}