/* ===== 基础重置与变量 ===== */
* { margin: 0; padding: 0; box-sizing: border-box; }

:root {
    --bg: #f5f5f5;
    --card-bg: #ffffff;
    --text: #2c2c2c;
    --text-light: #666666;
    --text-muted: #999999;
    --accent: #2563eb;
    --accent-soft: #4f46e5;
    --border: #e5e7eb;
    --tag-bg: #eef2ff;
    --tag-text: #4f46e5;
    --code-bg: #f6f8fa;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
                 "Hiragino Sans GB", "Microsoft YaHei", Roboto, Helvetica, Arial, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

#app { flex: 1; width: 100%; }

/* ===== 顶部品牌栏 ===== */
.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(255, 255, 255, 0.92);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--border);
    padding: 12px 24px;
}
.brand {
    display: inline-block;
    font-size: 18px;
    font-weight: 700;
    color: var(--text);
    text-decoration: none;
    letter-spacing: 0.06em;
    transition: color 0.2s ease;
}
.brand:hover { color: var(--accent); }

/* ===== 首页头部 ===== */
.home-header {
    text-align: center;
    padding: 64px 20px 32px;
}
.site-title {
    font-size: 40px;
    font-weight: 700;
    letter-spacing: 0.02em;
}
.site-subtitle {
    margin-top: 12px;
    color: var(--text-light);
    font-size: 18px;
}

/* ===== 分类筛选 ===== */
.filter-bar {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    justify-content: center;
    padding: 0 20px 36px;
}
.cat-btn {
    border: 1px solid var(--border);
    background: var(--card-bg);
    color: var(--text-light);
    padding: 6px 16px;
    border-radius: 999px;
    font-size: 14px;
    cursor: pointer;
    transition: all 0.2s ease;
}
.cat-btn:hover { border-color: var(--accent); color: var(--accent); }
.cat-btn.active { background: var(--accent); color: #fff; border-color: var(--accent); }

/* ===== 文章卡片网格 ===== */
.card-grid {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 20px 60px;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
}
.card {
    display: flex;
    flex-direction: column;
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 22px;
    text-decoration: none;
    color: inherit;
    transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}
.card:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.08);
    border-color: #c7d2fe;
}
.card-cat {
    align-self: flex-start;
    font-size: 12px;
    color: var(--tag-text);
    background: var(--tag-bg);
    padding: 2px 10px;
    border-radius: 999px;
    margin-bottom: 12px;
}
.card-title {
    font-size: 18px;
    font-weight: 600;
    line-height: 1.4;
    margin-bottom: 8px;
}
.card-summary {
    font-size: 14px;
    color: var(--text-light);
    line-height: 1.6;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

/* ===== 文章页 ===== */
.post-wrap {
    max-width: 760px;
    margin: 0 auto;
    padding: 32px 20px 60px;
}
.back {
    display: inline-block;
    margin-bottom: 24px;
    color: var(--text-muted);
    text-decoration: none;
    font-size: 14px;
}
.back:hover { color: var(--accent); }
.post-header {
    margin-bottom: 28px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border);
}
.post-title {
    font-size: 32px;
    font-weight: 700;
    margin-top: 12px;
    line-height: 1.3;
}

/* ===== Markdown 正文 ===== */
.markdown-body { font-size: 16px; line-height: 1.85; color: var(--text); word-wrap: break-word; }
.markdown-body h1 { font-size: 28px; margin: 32px 0 16px; }
.markdown-body h2 { font-size: 22px; margin: 28px 0 14px; padding-bottom: 6px; border-bottom: 1px solid var(--border); }
.markdown-body h3 { font-size: 19px; margin: 24px 0 12px; }
.markdown-body h4 { font-size: 17px; margin: 20px 0 10px; }
.markdown-body p { margin: 14px 0; }
.markdown-body ul, .markdown-body ol { margin: 14px 0; padding-left: 28px; }
.markdown-body li { margin: 6px 0; }
.markdown-body blockquote {
    border-left: 4px solid var(--accent);
    background: #fafafa;
    padding: 10px 16px;
    margin: 16px 0;
    color: var(--text-light);
    border-radius: 0 6px 6px 0;
}
.markdown-body code {
    background: var(--code-bg);
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 0.9em;
    font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
}
.markdown-body pre {
    background: var(--code-bg);
    border: 1px solid var(--border);
    padding: 16px 18px;
    border-radius: 8px;
    overflow-x: auto;
    margin: 16px 0;
}
.markdown-body pre code { background: transparent; padding: 0; color: #24292e; font-size: 14px; }
.markdown-body img { max-width: 100%; border-radius: 8px; }
.markdown-body table { border-collapse: collapse; margin: 16px 0; width: 100%; }
.markdown-body th, .markdown-body td { border: 1px solid var(--border); padding: 8px 12px; text-align: left; }
.markdown-body th { background: #fafafa; }
.markdown-body a { color: var(--accent); }
.markdown-body hr { border: none; border-top: 1px solid var(--border); margin: 24px 0; }
.markdown-body sup { font-size: 0.7em; vertical-align: super; }
.markdown-body sub { font-size: 0.7em; vertical-align: sub; }

/* ===== 加载与错误 ===== */
.loading, .error { padding: 40px; text-align: center; color: var(--text-muted); }

/* ===== 页脚 ===== */
.site-footer {
    text-align: center;
    padding: 20px;
    font-size: 14px;
    color: var(--text-muted);
    border-top: 1px solid var(--border);
    background: var(--card-bg);
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
    gap: 6px;
}
.site-footer a {
    color: var(--text-muted);
    text-decoration: none;
    transition: color 0.2s ease;
    display: inline-flex;
    align-items: center;
    gap: 4px;
}
.site-footer a:hover { color: var(--accent); }
.footer-sep { opacity: 0.5; }
.beian-icon { height: 14px; width: auto; vertical-align: middle; }

/* ===== 响应式 ===== */
@media (max-width: 768px) {
    .site-title { font-size: 28px; }
    .home-header { padding: 40px 20px 24px; }
    .post-title { font-size: 24px; }
    .markdown-body { font-size: 15px; }
    .markdown-body h1 { font-size: 24px; }
}