:root {
    --bg: #0a0a0a;
    --bg-card: #111;
    --bg-hover: #1a1a1a;
    --text: #e8e8e8;
    --text-secondary: #aaa;
    --text-muted: #888;
    --accent: #c9a96e;
    --border: #2a2a2a;
    --border-hover: #3a3a3a;
    --font-cn: "Noto Serif SC", "Songti SC", "PingFang SC", "Microsoft YaHei", serif;
    --font-en: "Helvetica Neue", Arial, sans-serif;
}

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

html { scroll-behavior: smooth; }

body {
    font-family: var(--font-cn);
    background: var(--bg);
    color: var(--text);
    line-height: 1.8;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
    padding-top: 60px;
}

a { text-decoration: none; color: inherit; }
img { max-width: 100%; display: block; }

/* ===== 导航 ===== */
.nav {
    position: fixed;
    top: 0; left: 0; right: 0;
    z-index: 1000;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 40px;
    height: 60px;
    background: rgba(10, 10, 10, 0.95);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
}

.nav-logo {
    color: var(--accent);
    font-family: var(--font-en);
    font-size: 18px;
    font-weight: 400;
    letter-spacing: 2px;
}

.nav-links {
    display: flex;
    gap: 32px;
    list-style: none;
}

.nav-links a {
    font-size: 14px;
    letter-spacing: 1px;
    color: #999;
    position: relative;
    transition: color 0.3s;
    display: block;
    padding: 5px 0;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 1px;
    background: var(--accent);
    transition: width 0.3s;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--accent);
}

.nav-links a:hover::after,
.nav-links a.active::after {
    width: 100%;
}

/* ===== 面包屑 ===== */
.breadcrumb {
    max-width: 1200px;
    margin: 0 auto;
    padding: 24px 40px 0;
    font-size: 12px;
    color: #666;
    letter-spacing: 1px;
}

.breadcrumb a { color: #888; transition: color 0.3s; }
.breadcrumb a:hover { color: var(--accent); }
.breadcrumb span { color: #444; margin: 0 8px; }

/* ===== 页面标题 ===== */
.page-header {
    padding: 40px 40px 30px;
    text-align: center;
}

.page-header h1 {
    font-family: var(--font-en);
    font-size: 14px;
    font-weight: 400;
    letter-spacing: 0.3em;
    color: #f5f0e8;
    text-transform: uppercase;
    margin-bottom: 12px;
}

.page-header .subtitle {
    font-size: 28px;
    color: var(--accent);
    letter-spacing: 0.15em;
    font-weight: 400;
}

.page-header .desc {
    font-size: 14px;
    color: #888;
    margin-top: 16px;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
    line-height: 2;
}

/* ===== 搜索栏 ===== */
.search-bar {
    max-width: 600px;
    margin: 0 auto 30px;
    padding: 0 40px;
    position: relative;
}

.search-bar input {
    width: 100%;
    padding: 14px 50px 14px 20px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 4px;
    color: var(--text);
    font-family: var(--font-cn);
    font-size: 14px;
    letter-spacing: 1px;
    outline: none;
    transition: border-color 0.3s;
}

.search-bar input::placeholder { color: #555; }
.search-bar input:focus { border-color: var(--accent); }

.search-bar .search-icon {
    position: absolute;
    right: 55px;
    top: 50%;
    transform: translateY(-50%);
    color: #555;
    font-size: 16px;
}

/* ===== 分类筛选 ===== */
.category-filter {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 12px;
    padding: 0 40px 30px;
    max-width: 900px;
    margin: 0 auto;
}

.category-filter button {
    background: transparent;
    border: 1px solid var(--border);
    color: var(--text-muted);
    padding: 8px 20px;
    font-family: var(--font-cn);
    font-size: 13px;
    letter-spacing: 1px;
    cursor: pointer;
    border-radius: 3px;
    transition: all 0.3s;
}

.category-filter button:hover,
.category-filter button.active {
    border-color: var(--accent);
    color: var(--accent);
}

/* ===== 卡片网格 ===== */
.card-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2px;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2px 40px;
}

.kb-card {
    position: relative;
    background: var(--bg-card);
    border: 1px solid var(--border);
    padding: 28px;
    cursor: pointer;
    transition: all 0.4s ease;
    min-height: 200px;
    display: flex;
    flex-direction: column;
}

.kb-card:hover {
    border-color: var(--border-hover);
    background: var(--bg-hover);
}

.kb-card .card-tag {
    font-size: 11px;
    letter-spacing: 1px;
    color: var(--accent);
    border: 1px solid rgba(201,169,110,0.3);
    padding: 3px 10px;
    display: inline-block;
    margin-bottom: 14px;
    align-self: flex-start;
}

.kb-card .card-title {
    font-size: 18px;
    font-weight: 400;
    letter-spacing: 2px;
    color: var(--text);
    margin-bottom: 8px;
}

.kb-card .card-alias {
    font-size: 12px;
    color: #666;
    letter-spacing: 1px;
    margin-bottom: 12px;
}

.kb-card .card-summary {
    font-size: 13px;
    color: var(--text-muted);
    line-height: 1.8;
    flex-grow: 1;
}

.kb-card .card-arrow {
    margin-top: 16px;
    font-size: 20px;
    color: var(--accent);
    opacity: 0;
    transition: opacity 0.3s;
}

.kb-card:hover .card-arrow {
    opacity: 1;
}

/* ===== 知识库内容页 ===== */
.kb-content {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px 40px 80px;
}

.kb-content .meta {
    margin-bottom: 30px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border);
}

.kb-content .meta-tag {
    font-size: 11px;
    letter-spacing: 1px;
    color: var(--accent);
    border: 1px solid rgba(201,169,110,0.3);
    padding: 3px 12px;
    display: inline-block;
    margin-bottom: 16px;
}

.kb-content h1 {
    font-size: 26px;
    font-weight: 400;
    letter-spacing: 3px;
    color: var(--text);
    margin-bottom: 10px;
}

.kb-content .meta-alias {
    font-size: 13px;
    color: #666;
    letter-spacing: 1px;
}

.kb-content h2 {
    font-size: 18px;
    font-weight: 400;
    letter-spacing: 2px;
    color: var(--accent);
    margin: 40px 0 16px;
    padding-bottom: 8px;
    border-bottom: 1px solid var(--border);
}

.kb-content h3 {
    font-size: 15px;
    font-weight: 400;
    letter-spacing: 1px;
    color: var(--text-secondary);
    margin: 24px 0 10px;
}

.kb-content p {
    font-size: 14px;
    color: var(--text-muted);
    line-height: 2;
    margin-bottom: 14px;
}

.kb-content ul, .kb-content ol {
    margin: 12px 0 20px 20px;
    color: var(--text-muted);
    font-size: 14px;
    line-height: 2;
}

.kb-content li {
    margin-bottom: 6px;
}

.kb-content strong {
    color: var(--text-secondary);
    font-weight: 400;
}

.kb-content table {
    width: 100%;
    border-collapse: collapse;
    margin: 20px 0;
    font-size: 13px;
}

.kb-content th,
.kb-content td {
    border: 1px solid var(--border);
    padding: 10px 14px;
    text-align: left;
    color: var(--text-muted);
}

.kb-content th {
    background: var(--bg-card);
    color: var(--accent);
    font-weight: 400;
    letter-spacing: 1px;
}

.kb-content tr:hover td {
    background: var(--bg-hover);
}

.kb-content blockquote {
    border-left: 2px solid var(--accent);
    padding-left: 16px;
    margin: 16px 0;
    color: var(--text-muted);
    font-style: italic;
}

/* ===== AI助手按钮 ===== */
.ai-button {
    position: fixed;
    bottom: 30px;
    right: 30px;
    z-index: 999;
    background: var(--accent);
    color: var(--bg);
    border: none;
    padding: 14px 28px;
    font-family: var(--font-cn);
    font-size: 14px;
    letter-spacing: 2px;
    cursor: pointer;
    border-radius: 4px;
    box-shadow: 0 4px 20px rgba(201,169,110,0.3);
    transition: all 0.3s;
}

.ai-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 30px rgba(201,169,110,0.4);
}

/* ===== 相关推荐 ===== */
.related-section {
    max-width: 800px;
    margin: 60px auto 0;
    padding: 40px 40px 0;
    border-top: 1px solid var(--border);
}

.related-section h3 {
    font-size: 14px;
    letter-spacing: 2px;
    color: var(--accent);
    margin-bottom: 20px;
}

.related-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
}

.related-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    padding: 18px;
    transition: all 0.3s;
}

.related-card:hover {
    border-color: var(--border-hover);
}

.related-card .related-tag {
    font-size: 10px;
    color: var(--accent);
    letter-spacing: 1px;
    margin-bottom: 6px;
}

.related-card .related-title {
    font-size: 14px;
    color: var(--text-secondary);
    letter-spacing: 1px;
}

/* ===== 页脚 ===== */
.footer {
    text-align: center;
    padding: 60px 40px;
    border-top: 1px solid var(--border);
    font-size: 12px;
    color: #444;
    letter-spacing: 2px;
}

/* ===== 响应式 ===== */
@media (max-width: 900px) {
    .card-grid { grid-template-columns: repeat(2, 1fr); }
    .related-grid { grid-template-columns: 1fr; }
}

@media (max-width: 768px) {
    .nav { padding: 0 20px; }
    .nav-links { gap: 20px; }
    .nav-links a { font-size: 12px; }
    .breadcrumb { padding: 20px 20px 0; }
    .page-header { padding: 30px 20px 20px; }
    .page-header .subtitle { font-size: 22px; }
    .search-bar { padding: 0 20px; }
    .category-filter { padding: 0 20px 20px; }
    .card-grid { grid-template-columns: 1fr; padding: 0 2px 20px; }
    .kb-content { padding: 20px 20px 60px; }
    .kb-content h1 { font-size: 22px; }
    .related-section { padding: 30px 20px 0; }
    .ai-button {
        bottom: 20px;
        right: 20px;
        padding: 12px 20px;
        font-size: 13px;
    }
}

/* ===== 隐藏类 ===== */
.hidden { display: none !important; }