.page-container {
    margin-top: 64px;
    min-height: calc(100vh - 64px);
    padding-bottom: 60px;
}

.page-header {
    background: linear-gradient(135deg, #DC143C 0%, #B91224 100%);
    color: white;
    padding: 60px 24px;
    text-align: center;
}

.page-header h1 {
    font-size: 42px;
    color: white;
    margin-bottom: 12px;
}

.page-header p {
    font-size: 18px;
    opacity: 0.9;
}

.filter-bar {
    display: flex;
    gap: 16px;
    margin: 32px 0 24px;
    flex-wrap: wrap;
}

.search-input {
    flex: 1;
    min-width: 300px;
    padding: 12px 16px;
    font-size: 15px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    outline: none;
    transition: border-color 0.3s;
}

.search-input:focus {
    border-color: var(--primary-color);
}

.filter-select {
    min-width: 180px;
    padding: 12px 16px;
    font-size: 15px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    outline: none;
    cursor: pointer;
    background: white;
    transition: border-color 0.3s;
}

.filter-select:focus {
    border-color: var(--primary-color);
}

.result-info {
    margin-bottom: 24px;
    color: #6B7280;
    font-size: 14px;
}

.result-info strong {
    color: var(--primary-color);
    font-weight: 600;
    font-size: 16px;
}

.topics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 24px;
    margin-bottom: 48px;
}

.topic-card {
    background: white;
    border-radius: 12px;
    overflow: hidden;
    transition: all 0.3s;
    cursor: pointer;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
    border: 1px solid var(--border-color);
}

.topic-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 12px 24px rgba(0, 0, 0, 0.12);
    border-color: var(--primary-color);
}

.topic-card-header {
    position: relative;
    height: 180px;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.topic-card-header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: inherit;
    opacity: 0.9;
}

.topic-emoji {
    font-size: 64px;
    position: relative;
    z-index: 1;
}

.topic-tags {
    position: absolute;
    top: 12px;
    left: 12px;
    right: 12px;
    display: flex;
    justify-content: space-between;
    z-index: 2;
}

.topic-category {
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 500;
    color: white;
}

.topic-category.philosophy { background: #8B4513; }
.topic-category.arts { background: #DC143C; }
.topic-category.architecture { background: #B8860B; }
.topic-category.festivals { background: #FF6347; }
.topic-category.symbols { background: #DC143C; }
.topic-category.heritage { background: #8B008B; }
.topic-category.modern { background: #4169E1; }

.topic-difficulty {
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 500;
    background: rgba(255, 255, 255, 0.9);
    color: #333;
}

.topic-card-body {
    padding: 20px;
}

.topic-title {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 8px;
    color: #1C1C1E;
    line-height: 1.4;
    min-height: 44px;
}

.topic-title-cn {
    font-size: 14px;
    color: var(--primary-color);
    font-family: 'Noto Serif SC', serif;
    margin-bottom: 12px;
    font-weight: 500;
}

.topic-description {
    font-size: 13px;
    color: var(--text-light);
    line-height: 1.6;
    margin-bottom: 16px;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.topic-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 16px;
    border-top: 1px solid var(--border-color);
}

.topic-action {
    color: var(--primary-color);
    font-size: 14px;
    font-weight: 500;
    transition: transform 0.3s;
}

.topic-card:hover .topic-action {
    transform: translateX(4px);
}

@media (max-width: 768px) {
    .page-header h1 {
        font-size: 32px;
    }

    .page-header p {
        font-size: 16px;
    }

    .filter-bar {
        flex-direction: column;
    }

    .search-input,
    .filter-select {
        width: 100%;
        min-width: 100%;
    }

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