/* Overview Page Styles */
.overview-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem 1rem;
}

.overview-title {
    font-size: 2rem;
    font-weight: bold;
    margin-bottom: 2rem;
    color: #000;
    border-bottom: 2px solid #000;
    padding-bottom: 0.5rem;
}

.overview-intro {
    font-size: 1.1rem;
    line-height: 1.6;
    margin-bottom: 3rem;
    color: #333;
}

.concepts-list {
    display: flex;
    flex-direction: column;
    gap: 2.5rem;
}

.concept-section {
    background: #fff;
    border: 1px solid #ddd;
    padding: 2rem;
}

.concept-title {
    font-size: 1.6rem;
    font-weight: bold;
    margin-bottom: 0.5rem;
}

.concept-link {
    text-decoration: underline;
    color: #0066cc;
    transition: color 0.2s ease;
}

.concept-link:hover {
    color: #004499;
}

.concept-description {
    font-size: 0.95rem;
    color: #666;
    line-height: 1.5;
    margin-bottom: 1.5rem;
}

/* Monthly items styles */
.monthly-items {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 0.75rem;
}

.month-item {
    padding: 0.5rem 0;
    border-bottom: 1px solid #e0e0e0;
    line-height: 1.6;
    font-size: 0.95rem;
}

.month-name {
    font-weight: 600;
    color: #333;
}

.item-name {
    color: #666;
}

.item-separator {
    color: #999;
}

/* Responsive adjustments */
@media (max-width: 768px) {
    .overview-container {
        padding: 1rem;
    }

    .overview-title {
        font-size: 1.5rem;
    }

    .concepts-grid {
        grid-template-columns: 1fr;
    }

    .months-concepts-table {
        font-size: 0.85rem;
    }

    .months-concepts-table th,
    .months-concepts-table td {
        padding: 0.5rem;
    }

    /* Make table scrollable on mobile */
    .monthly-table {
        overflow-x: auto;
        -webkit-overflow-scrolling: touch;
    }
    
    /* Remove border on mobile for better appearance */
    .month-item {
        border-bottom: none;
    }
}