* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #2563eb;
    --secondary-color: #64748b;
    --pro-color: #10b981;
    --neutral-color: #f59e0b;
    --con-color: #ef4444;
    --bg-color: #f8fafc;
    --text-color: #1e293b;
    --border-color: #e2e8f0;
    --card-bg: #ffffff;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
header {
    background-color: var(--card-bg);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
}

.logo a {
    color: var(--primary-color);
    text-decoration: none;
}

nav ul {
    display: flex;
    list-style: none;
    gap: 2rem;
}

nav a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: color 0.3s;
}

nav a:hover {
    color: var(--primary-color);
}

.language-switcher select {
    padding: 0.5rem;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    background-color: var(--card-bg);
    cursor: pointer;
}

/* Hot Topics */
.hot-topics {
    padding: 3rem 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.hot-topics h2 {
    margin-bottom: 2rem;
    font-size: 2rem;
}

.hot-topics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
}

.topic-card {
    background-color: var(--card-bg);
    border-radius: 8px;
    padding: 1.5rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s, box-shadow 0.3s;
    cursor: pointer;
    text-decoration: none;
    color: var(--text-color);
    display: block;
}

.topic-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 12px rgba(0, 0, 0, 0.15);
}

.topic-card h3 {
    margin-bottom: 0.5rem;
    color: var(--text-color);
    font-size: 1.25rem;
}

.topic-card .category-badge {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    background-color: var(--primary-color);
    color: white;
    border-radius: 12px;
    font-size: 0.75rem;
    margin-bottom: 0.5rem;
}

.topic-stats {
    display: flex;
    gap: 1rem;
    margin-top: 1rem;
}

.stat {
    display: flex;
    flex-direction: column;
    align-items: center;
    flex: 1;
    padding: 0.5rem;
    border-radius: 4px;
    background-color: var(--bg-color);
}

.stat-label {
    font-size: 0.875rem;
    color: var(--secondary-color);
    margin-bottom: 0.25rem;
}

.stat-count {
    font-size: 1.5rem;
    font-weight: bold;
}

.stat-pro {
    border-left: 3px solid var(--pro-color);
}

.stat-pro .stat-count {
    color: var(--pro-color);
}

.stat-neutral {
    border-left: 3px solid var(--neutral-color);
}

.stat-neutral .stat-count {
    color: var(--neutral-color);
}

.stat-con {
    border-left: 3px solid var(--con-color);
}

.stat-con .stat-count {
    color: var(--con-color);
}

/* Categories */
.categories {
    padding: 3rem 0;
}

.categories h2 {
    margin-bottom: 2rem;
    font-size: 2rem;
}

.category-tabs {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.category-tab {
    padding: 0.75rem 1.5rem;
    border: 2px solid var(--border-color);
    background-color: var(--card-bg);
    border-radius: 24px;
    cursor: pointer;
    transition: all 0.3s;
    font-weight: 500;
}

.category-tab:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.category-tab.active {
    background-color: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.topics-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 1.5rem;
}

/* Debate Detail */
.debate-detail {
    padding: 3rem 0;
}

.debate-header {
    background-color: var(--card-bg);
    padding: 2rem;
    border-radius: 8px;
    margin-bottom: 2rem;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.debate-header h1 {
    margin-bottom: 1rem;
    font-size: 2rem;
}

.debate-description {
    color: var(--secondary-color);
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
    line-height: 1.8;
}

.debate-stats {
    display: flex;
    gap: 2rem;
    justify-content: center;
}

.debate-stats .stat {
    min-width: 120px;
}

/* Comment Form */
.comment-form-section {
    background-color: var(--card-bg);
    padding: 2rem;
    border-radius: 8px;
    margin-bottom: 2rem;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.comment-form-section h3 {
    margin-bottom: 1.5rem;
}

.comment-form .form-group {
    margin-bottom: 1.5rem;
}

.comment-form label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.comment-form input,
.comment-form select,
.comment-form textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 1rem;
    font-family: inherit;
}

.comment-form textarea {
    resize: vertical;
}

.evidence-list {
    margin-bottom: 1rem;
}

.evidence-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem;
    background-color: var(--bg-color);
    border-radius: 4px;
    margin-bottom: 0.5rem;
}

.evidence-info {
    flex: 1;
}

.evidence-type {
    display: inline-block;
    padding: 0.25rem 0.5rem;
    background-color: var(--primary-color);
    color: white;
    border-radius: 4px;
    font-size: 0.75rem;
    margin-right: 0.5rem;
}

.evidence-url {
    color: var(--secondary-color);
    font-size: 0.875rem;
    word-break: break-all;
}

.remove-evidence {
    background-color: var(--con-color);
    color: white;
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    cursor: pointer;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 0.75rem 2rem;
    border-radius: 4px;
    font-size: 1rem;
    cursor: pointer;
    transition: background-color 0.3s;
}

.btn-primary:hover {
    background-color: #1d4ed8;
}

.btn-secondary {
    background-color: var(--secondary-color);
    color: white;
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.3s;
}

.btn-secondary:hover {
    background-color: #475569;
}

/* Comments Section */
.comments-section {
    background-color: var(--card-bg);
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.comments-tabs {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
    border-bottom: 2px solid var(--border-color);
}

.tab-btn {
    padding: 0.75rem 1.5rem;
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 500;
    color: var(--secondary-color);
    border-bottom: 3px solid transparent;
    transition: all 0.3s;
}

.tab-btn:hover {
    color: var(--primary-color);
}

.tab-btn.active {
    color: var(--primary-color);
    border-bottom-color: var(--primary-color);
}

.comments-list {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.comment-item {
    padding: 1.5rem;
    background-color: var(--bg-color);
    border-radius: 8px;
    border-left: 4px solid var(--border-color);
}

.comment-item.stance-pro {
    border-left-color: var(--pro-color);
}

.comment-item.stance-neutral {
    border-left-color: var(--neutral-color);
}

.comment-item.stance-con {
    border-left-color: var(--con-color);
}

.comment-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.comment-author {
    font-weight: 600;
}

.comment-stance {
    padding: 0.25rem 0.75rem;
    border-radius: 12px;
    font-size: 0.875rem;
    color: white;
}

.comment-stance.pro {
    background-color: var(--pro-color);
}

.comment-stance.neutral {
    background-color: var(--neutral-color);
}

.comment-stance.con {
    background-color: var(--con-color);
}

.comment-text {
    margin-bottom: 1rem;
    line-height: 1.8;
}

.comment-evidence {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.comment-evidence-item {
    padding: 0.5rem;
    background-color: var(--card-bg);
    border-radius: 4px;
    font-size: 0.875rem;
}

.comment-evidence-item a {
    color: var(--primary-color);
    text-decoration: none;
}

.comment-evidence-item a:hover {
    text-decoration: underline;
}

.comment-date {
    color: var(--secondary-color);
    font-size: 0.875rem;
    margin-top: 0.5rem;
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
}

.modal.active {
    display: flex;
    justify-content: center;
    align-items: center;
}

.modal-content {
    background-color: var(--card-bg);
    padding: 2rem;
    border-radius: 8px;
    max-width: 500px;
    width: 90%;
    position: relative;
}

.close {
    position: absolute;
    right: 1rem;
    top: 1rem;
    font-size: 2rem;
    cursor: pointer;
    color: var(--secondary-color);
}

.close:hover {
    color: var(--text-color);
}

/* Footer */
footer {
    background-color: var(--text-color);
    color: white;
    padding: 2rem 0;
    text-align: center;
    margin-top: 4rem;
}

/* Responsive */
@media (max-width: 768px) {
    .header-content {
        flex-direction: column;
        gap: 1rem;
    }

    nav ul {
        gap: 1rem;
    }

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

    .debate-stats {
        flex-direction: column;
        gap: 1rem;
    }

    .comments-tabs {
        flex-wrap: wrap;
    }

    .tab-btn {
        padding: 0.5rem 1rem;
        font-size: 0.875rem;
    }
}