/* ========================================
   LESSON NAVIGATION (Generic)
   ======================================== */

.navigation-section {
    padding: 2rem 2.5rem;
    background: #f8fafc;
    border-top: 1px solid var(--border-color);
}

.lesson-navigation {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
}

.nav-button {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1.25rem;
    border-radius: var(--radius-md);
    border: 2px solid var(--border-color);
    background: white;
    text-decoration: none;
    color: var(--primary-dark);
    transition: var(--transition);
}

.nav-button:hover {
    border-color: var(--primary-medium);
    background: rgba(51, 102, 153, 0.02);
    transform: translateY(-2px);
    box-shadow: 0 4px 20px rgba(51, 102, 153, 0.1);
    text-decoration: none;
    color: var(--primary-dark);
}

.nav-button.disabled {
    opacity: 0.5;
    cursor: not-allowed;
    border-color: #f1f5f9;
    background: #f8fafc;
}

.nav-button.disabled:hover {
    transform: none;
    box-shadow: none;
    border-color: #f1f5f9;
    background: #f8fafc;
}

.nav-icon {
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, var(--primary-medium) 0%, var(--primary-dark) 100%);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.1rem;
    flex-shrink: 0;
}

.nav-button.disabled .nav-icon {
    background: #cbd5e1;
}

.nav-content {
    flex-grow: 1;
    min-width: 0;
}

.nav-title {
    font-weight: 600;
    font-size: 1rem;
    margin-bottom: 0.25rem;
    color: var(--primary-dark);
}

.nav-subtitle {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin: 0;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

/* ========================================
   RESPONSIVE
   ======================================== */

@media (max-width: 768px) {
    .navigation-section {
        padding: 1.5rem;
    }

    .lesson-navigation {
        grid-template-columns: 1fr;
        gap: 1rem;
    }

    .nav-button {
        padding: 1rem;
    }
}