/* ============================================
   AI 博客 · 现代简约风格
   ============================================ */
:root{
  --bg:#fafafa;
  --card:#ffffff;
  --ink:#18181b;
  --muted:#71717a;
  --line:#e4e4e7;
  --accent:#2563eb;
  --accent-soft:#eff6ff;
  --radius:16px;
  --shadow:0 1px 3px rgba(0,0,0,.05),0 8px 24px rgba(0,0,0,.05);
  --shadow-hover:0 4px 12px rgba(0,0,0,.06),0 16px 40px rgba(0,0,0,.10);
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  background:var(--bg);color:var(--ink);line-height:1.7;-webkit-font-smoothing:antialiased;
}
a{color:inherit;text-decoration:none}
img{max-width:100%;display:block}

.container{max-width:1120px;margin:0 auto;padding:0 24px}

/* ---------- 顶栏 ---------- */
.topbar{
  position:sticky;top:0;z-index:50;
  background:rgba(250,250,250,.85);backdrop-filter:blur(12px);
  border-bottom:1px solid var(--line);
}
.tb-inner{display:flex;align-items:center;justify-content:space-between;height:64px}
.brand{font-size:20px;font-weight:800;letter-spacing:-.02em}
.brand .dot{color:var(--accent)}
.nav{display:flex;gap:4px}
.nav a{
  font-size:14px;color:var(--muted);padding:8px 14px;border-radius:999px;
  transition:.2s;font-weight:500;
}
.nav a:hover,.nav a.active{color:var(--ink);background:var(--card)}
.menu-btn{display:none}

/* ---------- 英雄区 ---------- */
.hero{padding:72px 0 40px}
.hero .kicker{display:inline-block;font-size:13px;color:var(--accent);background:var(--accent-soft);
  padding:6px 14px;border-radius:999px;font-weight:600;margin-bottom:20px}
.hero h1{font-size:clamp(32px,6vw,56px);font-weight:800;letter-spacing:-.03em;line-height:1.15;max-width:720px}
.hero h1 .hl{background:linear-gradient(120deg,var(--accent),#7c3aed);-webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent}
.hero p{margin-top:16px;color:var(--muted);font-size:17px;max-width:560px}

/* ---------- 分类标签 ---------- */
.cats{display:flex;gap:10px;flex-wrap:wrap;padding:8px 0 24px;border-bottom:1px solid var(--line);margin-bottom:32px}
.cat{
  font-size:14px;padding:7px 18px;border-radius:999px;border:1px solid var(--line);
  color:var(--muted);cursor:pointer;transition:.2s;background:transparent;font-family:inherit;
}
.cat:hover{border-color:var(--accent);color:var(--accent)}
.cat.active{background:var(--ink);border-color:var(--ink);color:#fff}

/* ---------- 文章网格 ---------- */
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(320px,1fr));gap:28px;padding-bottom:80px}
.card{
  background:var(--card);border:1px solid var(--line);border-radius:var(--radius);
  overflow:hidden;transition:.25s;cursor:pointer;display:flex;flex-direction:column;
}
.card:hover{transform:translateY(-5px);box-shadow:var(--shadow-hover);border-color:#d4d4d8}
.card-cover{aspect-ratio:16/10;overflow:hidden;position:relative}
.card-cover img{width:100%;height:100%;object-fit:cover;transition:transform .5s}
.card:hover .card-cover img{transform:scale(1.05)}
.card-tag{position:absolute;top:12px;left:12px;background:rgba(24,24,27,.75);backdrop-filter:blur(4px);
  color:#fff;font-size:12px;padding:4px 10px;border-radius:999px;font-weight:500}
.card-body{padding:20px 22px 24px;display:flex;flex-direction:column;flex:1}
.card-body h3{font-size:18px;font-weight:700;line-height:1.4;margin-bottom:8px}
.card-body p{color:var(--muted);font-size:14px;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.meta{display:flex;align-items:center;gap:14px;margin-top:16px;color:var(--muted);font-size:13px}
.meta .author{display:flex;align-items:center;gap:8px}
.meta .ava{width:24px;height:24px;border-radius:50%;background:linear-gradient(135deg,var(--accent),#7c3aed);color:#fff;display:flex;align-items:center;justify-content:center;font-size:11px;font-weight:700}

/* ---------- 详情页（杂志式图文排版） ---------- */
.post-wrap{max-width:928px;margin:0 auto;padding:40px 0 80px}
.back{display:inline-flex;align-items:center;gap:6px;color:var(--muted);font-size:14px;margin-bottom:28px;transition:.2s}
.back:hover{color:var(--ink)}

/* 文章头部：标题左对齐，不再居中 */
.post-head{max-width:720px}
.post-head .tag{color:var(--accent);font-size:13px;font-weight:600;background:var(--accent-soft);padding:5px 12px;border-radius:999px;display:inline-block;margin-bottom:18px;letter-spacing:.02em}
.post-head h1{font-size:clamp(26px,4.6vw,42px);font-weight:800;line-height:1.28;letter-spacing:-.02em;margin-bottom:18px;text-align:left}
.post-meta{display:flex;align-items:center;gap:20px;color:var(--muted);font-size:14px;flex-wrap:wrap;margin-bottom:32px}
.post-meta .author{display:flex;align-items:center;gap:12px}
.post-meta .ava{width:44px;height:44px;border-radius:50%;background:linear-gradient(135deg,var(--accent),#7c3aed);color:#fff;display:flex;align-items:center;justify-content:center;font-size:16px;font-weight:700}
.post-meta .meta-txt b{display:block;color:var(--ink);font-size:15px;line-height:1.2}
.post-meta .meta-txt span{font-size:13px;color:var(--muted)}
.post-meta .divider{width:1px;height:20px;background:var(--line)}
.post-meta .meta-stats{display:flex;align-items:center;gap:10px}
.post-meta .meta-stats span{display:inline-flex;align-items:center;gap:6px;white-space:nowrap}
.post-meta .meta-stats .ph{opacity:.65;font-size:15px}

/* 封面：全宽大图 */
.post-cover{border-radius:var(--radius);overflow:hidden;margin:0 0 36px;box-shadow:var(--shadow)}
.post-cover img{width:100%;aspect-ratio:21/8;object-fit:cover}

/* 正文：加宽版式但文字左对齐，图片居中插图化 */
.post-body{font-size:17px;max-width:720px;text-align:left}
.post-body h2{font-size:24px;font-weight:700;margin:40px 0 14px;padding-bottom:10px;border-bottom:1px solid var(--line);line-height:1.4;position:relative;padding-left:14px}
.post-body h2::before{content:"";position:absolute;left:0;top:.32em;bottom:.32em;width:4px;border-radius:2px;background:linear-gradient(var(--accent),#7c3aed)}
.post-body h3{font-size:19px;font-weight:700;margin:30px 0 10px}
.post-body p{margin-bottom:18px;color:#27272a;line-height:1.85}
.post-body ul,.post-body ol{margin:0 0 20px 6px;color:#27272a}
.post-body li{margin-bottom:10px;padding-left:4px}
.post-body li::marker{color:var(--accent);font-weight:700}
.post-body strong{color:var(--ink);font-weight:700}
.post-body blockquote{border-left:4px solid var(--accent);background:var(--accent-soft);padding:16px 22px;border-radius:0 12px 12px 0;margin:24px 0;color:#1e3a8a;font-style:italic;line-height:1.7}
.post-body blockquote p{margin:0;color:inherit}
/* 正文插图：居中对称、圆角、阴影 */
.post-body img{border-radius:12px;margin:28px auto;max-width:100%;box-shadow:var(--shadow)}
/* 宽排插图（通过 wrapper 实现，这里用于直连的 img） */
.post-body figure{margin:30px 0;text-align:center}
.post-body figure img{border-radius:12px;box-shadow:var(--shadow);margin:0 auto}
.post-body figcaption{font-size:13px;color:var(--muted);margin-top:12px;text-align:center}
.post-body code{background:#f4f4f5;padding:2px 7px;border-radius:6px;font-size:15px;font-family:ui-monospace,Consolas,monospace;color:#be185d}
.post-body pre{background:var(--ink);color:#e4e4e7;padding:20px 22px;border-radius:12px;overflow-x:auto;margin:24px 0;line-height:1.7;box-shadow:var(--shadow)}
.post-body pre code{background:none;padding:0;color:inherit}
.post-body .tip{background:#ecfdf5;border:1px solid #a7f3d0;border-radius:12px;padding:16px 22px;margin:24px 0;color:#065f46;line-height:1.7}
.post-body .tip b{color:#047857}
.post-end{border-top:1px solid var(--line);margin-top:48px;padding-top:28px;display:flex;align-items:center;gap:14px;color:var(--muted);font-size:14px;max-width:720px}

/* 相关推荐 */
.related{max-width:928px;margin-top:56px;padding-top:36px;border-top:1px solid var(--line)}
.related-head{display:flex;align-items:center;justify-content:space-between;margin-bottom:22px}
.related-head h2{font-size:22px;font-weight:800;letter-spacing:-.01em;position:relative;padding-left:14px}
.related-head h2::before{content:"";position:absolute;left:0;top:.2em;bottom:.2em;width:4px;border-radius:2px;background:linear-gradient(var(--accent),#7c3aed)}
.more-link{font-size:14px;color:var(--accent);font-weight:600;transition:.2s}
.more-link:hover{color:#1d4ed8}
.related-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:20px}
.related-card{background:var(--card);border:1px solid var(--line);border-radius:14px;overflow:hidden;transition:.22s;display:block}
.related-card:hover{transform:translateY(-4px);box-shadow:var(--shadow-hover);border-color:#d4d4d8}
.rel-cover{aspect-ratio:16/9;overflow:hidden;position:relative}
.rel-cover img{width:100%;height:100%;object-fit:cover;transition:transform .45s}
.related-card:hover .rel-cover img{transform:scale(1.05)}
.rel-tag{position:absolute;top:10px;left:10px;background:rgba(24,24,27,.72);backdrop-filter:blur(4px);color:#fff;font-size:12px;padding:3px 9px;border-radius:999px;font-weight:500}
.rel-body{padding:14px 16px 16px}
.rel-body h4{font-size:15px;font-weight:700;line-height:1.4;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden;min-height:42px}
.rel-meta{display:block;margin-top:8px;color:var(--muted);font-size:12px}
@media(max-width:720px){
  .related-grid{grid-template-columns:1fr 1fr}
}
@media(max-width:480px){
  .related-grid{grid-template-columns:1fr}
}

/* 响应式：移动端封面比例调整 */
@media(max-width:640px){
  .post-wrap{padding:28px 0 60px}
  .post-cover img{aspect-ratio:16/9}
  .post-body{font-size:16px}
}

/* ---------- 页脚 ---------- */
.footer{border-top:1px solid var(--line);padding:36px 0;text-align:center;color:var(--muted);font-size:14px}
.footer .brand{display:block;margin-bottom:10px}

/* ---------- 响应式 ---------- */
@media(max-width:720px){
  .nav{display:none;position:absolute;top:64px;right:16px;left:16px;background:var(--card);border:1px solid var(--line);
    border-radius:12px;flex-direction:column;padding:12px;box-shadow:var(--shadow)}
  .nav.open{display:flex}
  .menu-btn{display:block;background:none;border:0;cursor:pointer;color:var(--ink)}
  .hero{padding:48px 0 32px}
  .grid{grid-template-columns:1fr}
}

/* ---------- 空态 & 加载 ---------- */
.empty{text-align:center;padding:80px 0;color:var(--muted)}
.spinner{width:40px;height:40px;border:3px solid var(--line);border-top-color:var(--accent);border-radius:50%;margin:80px auto;animation:spin 1s linear infinite}
@keyframes spin{to{transform:rotate(360deg)}}
body.dark{--bg:#0b0b0e;--card:#131316;--ink:#f4f4f5;--muted:#a1a1aa;--line:#27272a;--accent:#3b82f6;--accent-soft:#172237}