/* =====================================================
   文章站 · 内容页样式
   ===================================================== */
:root{
  --bg:#f8fafc; --panel:#ffffff; --text:#1e293b; --muted:#64748b;
  --line:#e2e8f0; --primary:#2563eb; --primary-l:#eff6ff;
  --radius:12px; --shadow:0 2px 12px rgba(15,23,42,.06);
  --font:system-ui,-apple-system,"Microsoft YaHei","PingFang SC",sans-serif;
}
*{box-sizing:border-box;margin:0;padding:0}
body{font-family:var(--font);background:var(--bg);color:var(--text);font-size:15px;line-height:1.7}
a{color:inherit;text-decoration:none}
.container{max-width:1080px;margin:0 auto;padding:0 20px}

/* ---- 阅读进度条 ---- */
.progress{position:fixed;top:0;left:0;right:0;height:3px;z-index:99;background:transparent}
.progress i{display:block;height:100%;width:0;background:linear-gradient(90deg,#2563eb,#7c3aed)}

/* ---- 顶部导航 ---- */
.site-header{background:var(--primary);position:sticky;top:0;z-index:50;box-shadow:0 2px 8px rgba(0,0,0,.15)}
.header-inner{display:flex;align-items:center;gap:22px;height:60px}
.logo{display:inline-flex;align-items:center;gap:9px;font-size:18px;font-weight:800;letter-spacing:.5px;color:#fff;white-space:nowrap}
.logo-img{width:28px;height:28px;border-radius:7px;display:block;flex:none}
.nav{display:flex;gap:4px;overflow-x:auto;flex:1;scrollbar-width:none}
.nav::-webkit-scrollbar{display:none}
.nav a{padding:7px 13px;border-radius:8px;font-size:14px;color:rgba(255,255,255,.8);white-space:nowrap;transition:.15s}
.nav a:hover{color:#fff;background:rgba(255,255,255,.15)}
.search{display:flex;flex:0 0 220px}
.search input{flex:1;border:1px solid rgba(255,255,255,.2);border-right:none;border-radius:9px 0 0 9px;padding:8px 13px;font-size:13px;background:rgba(255,255,255,.15);color:#fff;outline:none}
.search input::placeholder{color:rgba(255,255,255,.5)}
.search input:focus{border-color:rgba(255,255,255,.5);background:rgba(255,255,255,.2)}
.search button{border:none;background:rgba(255,255,255,.2);color:#fff;padding:0 16px;border-radius:0 9px 9px 0;font-size:13px;cursor:pointer}
.search button:hover{background:rgba(255,255,255,.3)}

/* ---- 内容页布局 ---- */
.post-page{padding:26px 0 30px}
.breadcrumb{font-size:13px;color:var(--muted);margin-bottom:18px;display:flex;gap:8px;align-items:center;flex-wrap:wrap}
.breadcrumb a:hover{color:var(--primary)}
.breadcrumb em{color:var(--text)}
.post-layout{display:grid;grid-template-columns:minmax(0,1fr) 260px;gap:28px;align-items:start}
.post-main{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);padding:34px 38px}
.post-head{border-bottom:1px solid var(--line);padding-bottom:18px;margin-bottom:26px}
.post-title{font-size:26px;line-height:1.45;margin-bottom:12px}

/* ---- 正文排版 ---- */
.article-content{font-size:16px;line-height:1.95;word-break:break-word}
.article-content p{margin:0 0 18px}
.article-content h2{font-size:21px;margin:34px 0 14px;padding-left:12px;border-left:4px solid var(--primary)}
.article-content h3{font-size:18px;margin:26px 0 12px}
.article-content h4{font-size:16px;margin:22px 0 10px}
.article-content a{color:var(--primary);border-bottom:1px dashed currentColor}
.article-content img{max-width:100%;height:auto;border-radius:10px;margin:8px 0;cursor:zoom-in;box-shadow:var(--shadow)}
.article-content ul,.article-content ol{padding-left:26px;margin:0 0 18px}
.article-content li{margin-bottom:6px}
.article-content blockquote{margin:20px 0;padding:14px 18px;background:var(--primary-l);border-left:4px solid var(--primary);border-radius:0 10px 10px 0;color:#334155}
.article-content blockquote p{margin:0}
.article-content code{font-family:Consolas,"Courier New",monospace;font-size:13.5px;background:#f1f5f9;border:1px solid var(--line);border-radius:5px;padding:1px 6px;color:#c2410c}
.article-content pre{background:#0f172a;color:#e2e8f0;border-radius:10px;padding:18px 20px;overflow-x:auto;margin:20px 0;font-size:13.5px;line-height:1.75}
.article-content pre code{background:none;border:none;color:inherit;padding:0}
.article-content table{width:100%;border-collapse:collapse;margin:20px 0;font-size:14px;display:block;overflow-x:auto}
.article-content th,.article-content td{border:1px solid var(--line);padding:10px 13px;text-align:left}
.article-content th{background:#f1f5f9;font-weight:600}
.article-content tr:nth-child(even) td{background:#fafbfc}
.article-content hr{border:none;border-top:1px solid var(--line);margin:28px 0}

/* ---- 上下篇 ---- */
.post-nav{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin-top:26px}
.post-nav-item{background:var(--bg);border:1px solid var(--line);border-radius:10px;padding:13px 16px;display:flex;flex-direction:column;gap:5px}
.post-nav-item span{font-size:12px;color:var(--muted)}
.post-nav-item a{font-size:14px;font-weight:600;line-height:1.5;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.post-nav-item a:hover{color:var(--primary)}
.post-nav-item.next{text-align:right}

/* ---- 侧栏目录 ---- */
.toc-card{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);padding:18px;position:sticky;top:80px}
.toc-card h3{font-size:13px;color:var(--muted);margin-bottom:12px;letter-spacing:.05em}
.toc{display:flex;flex-direction:column;gap:2px;max-height:60vh;overflow-y:auto}
.toc a{font-size:13px;color:var(--muted);padding:6px 10px;border-radius:7px;border-left:2px solid transparent;line-height:1.5}
.toc a.lv3{padding-left:24px}
.toc a:hover{color:var(--primary)}
.toc a.active{color:var(--primary);background:var(--primary-l);border-left-color:var(--primary);font-weight:600}

/* ---- 相关阅读 ---- */
.related{margin:34px 0 10px}
.section-title{font-size:18px;margin-bottom:16px;padding-left:12px;border-left:4px solid var(--primary)}
.related-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}
.related-item{background:var(--panel);border:1px solid var(--line);border-radius:10px;padding:16px;display:flex;flex-direction:column;gap:7px;transition:.15s}
.related-item:hover{border-color:var(--primary);box-shadow:var(--shadow);transform:translateY(-2px)}
.ri-title{font-size:14.5px;font-weight:600;line-height:1.55;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.ri-meta{font-size:12px;color:var(--muted)}

/* ---- 返回顶部 / 图片放大 ---- */
.backtop{position:fixed;right:24px;bottom:30px;width:44px;height:44px;border-radius:50%;border:none;background:var(--primary);color:#fff;font-size:18px;cursor:pointer;box-shadow:0 6px 18px rgba(37,99,235,.35);opacity:0;visibility:hidden;transform:translateY(8px);transition:.2s}
.backtop.show{opacity:1;visibility:visible;transform:none}
.backtop:hover{background:#1d4ed8}
.img-viewer{position:fixed;inset:0;background:rgba(15,23,42,.88);z-index:200;display:none;align-items:center;justify-content:center;cursor:zoom-out;padding:24px}
.img-viewer.show{display:flex}
.img-viewer img{max-width:94vw;max-height:92vh;border-radius:8px;box-shadow:0 20px 60px rgba(0,0,0,.5)}

/* ---- 页脚 ---- */
.site-footer{border-top:1px solid var(--line);background:var(--panel);margin-top:26px;padding:26px 0}
.site-footer p{font-size:13px;color:var(--muted);text-align:center;margin-bottom:4px}
.site-footer .copy{font-size:12px;color:#94a3b8}

/* ---- 响应式 ---- */
@media (max-width:900px){
  .post-layout{grid-template-columns:1fr}
  .post-aside{order:-1}
  .toc-card{position:static}
  .related-grid{grid-template-columns:1fr}
  .post-main{padding:24px 20px}
  .post-title{font-size:21px}
  .search{flex:0 0 150px}
  .header-inner{gap:12px}
}
@media (max-width:600px){
  .nav{display:none}
  .search{flex:1}
  .post-nav{grid-template-columns:1fr}
  .post-nav-item.next{text-align:left}
}