:root {
  --bg: #f5f7fb;
  --bg-soft: #eef2fb;
  --card: #ffffff;
  --ink: #1f2733;
  --ink-soft: #5b6675;
  --ink-faint: #93a0b4;
  --brand: #5b6cff;
  --brand-2: #2dd4bf;
  --line: #e6eaf2;
  --shadow: 0 6px 24px rgba(40, 56, 110, 0.08);
  --shadow-hover: 0 12px 32px rgba(40, 56, 110, 0.14);
  --radius: 16px;
  --maxw: 1140px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }

/* ---------- 顶栏 ---------- */
.topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.82);
  backdrop-filter: saturate(160%) blur(12px);
  border-bottom: 1px solid var(--line);
}
.topbar-inner {
  max-width: var(--maxw);
  margin: 0 auto;
  height: 64px;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  font-size: 19px;
  letter-spacing: 0.5px;
}
.brand-logo { display: inline-flex; }
.brand-text em {
  font-style: normal;
  background: linear-gradient(120deg, var(--brand), var(--brand-2));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  margin-left: 2px;
}
.topnav { display: flex; gap: 6px; }
.topnav a {
  padding: 8px 14px;
  border-radius: 10px;
  color: var(--ink-soft);
  font-weight: 600;
  font-size: 14px;
  transition: all 0.18s ease;
}
.topnav a:hover { background: var(--bg-soft); color: var(--ink); }
.topnav a.active { color: var(--brand); background: var(--bg-soft); }

/* ---------- Hero ---------- */
.hero {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 56px 24px 28px;
  text-align: center;
}
.hero h1 {
  margin: 0;
  font-size: clamp(30px, 5vw, 46px);
  font-weight: 900;
  letter-spacing: 1px;
  background: linear-gradient(120deg, #4f5dff 0%, #2dd4bf 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero-sub {
  margin: 14px 0 0;
  color: var(--ink-soft);
  font-size: 16px;
}
.hero-stats {
  margin-top: 20px;
  color: var(--ink-faint);
  font-size: 14px;
}
.hero-stats span { color: var(--brand); font-weight: 800; }
.hero-stats .dot { margin: 0 8px; }

/* ---------- 布局 ---------- */
.layout {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 8px 24px 48px;
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 28px;
  align-items: start;
}

/* ---------- 侧边分类 ---------- */
.sidebar {
  position: sticky;
  top: 88px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px;
  box-shadow: var(--shadow);
}
.side-title {
  margin: 0 0 12px;
  font-size: 13px;
  letter-spacing: 2px;
  color: var(--ink-faint);
  text-transform: uppercase;
}
.cat-list { list-style: none; margin: 0; padding: 0; }
.cat-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  border-radius: 12px;
  color: var(--ink-soft);
  font-weight: 600;
  transition: all 0.16s ease;
}
.cat-item:hover { background: var(--bg-soft); color: var(--ink); }
.cat-item.active {
  background: linear-gradient(120deg, rgba(91, 108, 255, 0.12), rgba(45, 212, 191, 0.12));
  color: var(--brand);
}
.cat-icon { font-size: 18px; line-height: 1; }
.cat-name { flex: 1; }
.cat-num {
  font-size: 12px;
  color: var(--ink-faint);
  background: var(--bg-soft);
  border-radius: 999px;
  padding: 1px 9px;
  font-weight: 700;
}

/* ---------- 内容区 ---------- */
.content-head {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 18px;
}
.content-head h2 { margin: 0; font-size: 22px; font-weight: 800; }
.list-count { color: var(--ink-faint); font-size: 13px; }

.article-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 18px;
}

/* ---------- 文章卡片 ---------- */
.card {
  display: flex;
  flex-direction: column;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px;
  box-shadow: var(--shadow);
  transition: transform 0.18s ease, box-shadow 0.18s ease, border-color 0.18s ease;
}
.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
  border-color: rgba(91, 108, 255, 0.35);
}
.card-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 12px;
  color: var(--ink-faint);
  margin-bottom: 10px;
}
.card-cat { color: var(--brand); font-weight: 700; }
.card-title {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 800;
  line-height: 1.45;
  color: var(--ink);
}
.card-excerpt {
  margin: 0 0 14px;
  font-size: 13.5px;
  color: var(--ink-soft);
  flex: 1;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.card-tags { display: flex; flex-wrap: wrap; gap: 6px; }

.tag {
  font-size: 11.5px;
  color: var(--ink-soft);
  background: var(--bg-soft);
  border-radius: 999px;
  padding: 2px 10px;
  font-weight: 600;
}

.empty-tip {
  text-align: center;
  color: var(--ink-faint);
  padding: 60px 0;
}

/* ---------- 详情页 ---------- */
.post {
  max-width: 760px;
  margin: 0 auto;
  padding: 36px 24px 60px;
}
.back-btn {
  border: 1px solid var(--line);
  background: var(--card);
  color: var(--ink-soft);
  border-radius: 10px;
  padding: 8px 16px;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.16s ease;
  margin-bottom: 22px;
}
.back-btn:hover { color: var(--brand); border-color: rgba(91, 108, 255, 0.4); }
.post-meta-top {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  font-size: 13px;
  color: var(--ink-faint);
  margin-bottom: 12px;
}
.post-cat { color: var(--brand); font-weight: 700; }
.post-title {
  margin: 0 0 16px;
  font-size: clamp(26px, 4vw, 36px);
  font-weight: 900;
  line-height: 1.3;
}
.post-tags { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 28px; }
.post-body { font-size: 16px; color: #2b3543; }
.post-body h3 {
  margin: 30px 0 12px;
  font-size: 20px;
  font-weight: 800;
  color: var(--ink);
}
.post-body p { margin: 14px 0; }
.post-body ul, .post-body ol { padding-left: 22px; margin: 14px 0; }
.post-body li { margin: 6px 0; }
.post-body pre {
  background: #0f172a;
  color: #e2e8f0;
  border-radius: 12px;
  padding: 16px 18px;
  overflow-x: auto;
  font-size: 13.5px;
  line-height: 1.6;
  margin: 18px 0;
}
.post-body code {
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  font-size: 0.92em;
}
.post-body p code {
  background: var(--bg-soft);
  color: #d6336c;
  padding: 2px 6px;
  border-radius: 6px;
}
.post-body blockquote {
  margin: 20px 0;
  padding: 12px 18px;
  border-left: 4px solid var(--brand);
  background: linear-gradient(120deg, rgba(91, 108, 255, 0.06), rgba(45, 212, 191, 0.06));
  border-radius: 0 10px 10px 0;
  color: var(--ink-soft);
}
.post-divider {
  border: none;
  border-top: 1px solid var(--line);
  margin: 40px 0 24px;
}
.rel-title { font-size: 18px; font-weight: 800; margin: 0 0 14px; }
.rel-list { display: grid; gap: 10px; }
.rel-card {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 16px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 12px;
  font-weight: 600;
  transition: all 0.16s ease;
}
.rel-card:hover { border-color: rgba(91, 108, 255, 0.4); color: var(--brand); }
.rel-cat { font-size: 18px; }
.rel-empty { color: var(--ink-faint); font-size: 14px; }

/* ---------- 关于 ---------- */
.about {
  max-width: 720px;
  margin: 0 auto;
  padding: 60px 24px;
}
.about h1 {
  font-size: 30px;
  font-weight: 900;
  background: linear-gradient(120deg, var(--brand), var(--brand-2));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.about p { color: var(--ink-soft); font-size: 16px; }
.about-sign { color: var(--brand); font-weight: 700; margin-top: 24px; }

/* ---------- 页脚 ---------- */
.site-footer {
  border-top: 1px solid var(--line);
  background: var(--card);
  text-align: center;
  color: var(--ink-faint);
  font-size: 13px;
  padding: 22px 16px;
}
.footer-sep { margin: 0 10px; }

/* ---------- 响应式 ---------- */
@media (max-width: 860px) {
  .layout { grid-template-columns: 1fr; }
  .sidebar { position: static; }
  .cat-list {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
  }
  .cat-item { padding: 8px 12px; }
  .cat-num { display: none; }
}
@media (max-width: 520px) {
  .topbar-inner { padding: 0 16px; }
  .hero { padding: 40px 16px 20px; }
  .layout { padding: 8px 16px 40px; }
  .article-grid { grid-template-columns: 1fr; }
}