:root{
  --primary:#1871ff; --primary-bg:#e8f1ff; --primary-dark:#0f5fd9;
  --text:#262626; --nav:#67676c; --muted:#929295; --title:#3c3c43;
  --border:#e2e2e3; --aside-bg:#f6f6f7; --hover:#f0f0f0;
  --warn-bg:#fff7e6; --warn-border:#ffc53d;
}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei",sans-serif;color:var(--text);background:#fff;line-height:1.75;font-size:14px}
a{color:var(--primary);text-decoration:none}a:hover{color:var(--primary-dark)}
ul{list-style:none}

/* Header */
.topbar{height:65px;background:#fff;border-bottom:1px solid var(--border);display:flex;align-items:center;padding:0 32px;position:sticky;top:0;z-index:20}
.topbar .logo{font-size:16px;font-weight:600;color:var(--text);display:flex;align-items:center;gap:6px}
.topbar .logo .logo-mark{color:var(--primary);font-size:18px}
.topbar .logo img.logo-mark{height:44px;width:auto;object-fit:contain;display:block}
.topbar .logo span{color:var(--primary)}
.top-search{margin-left:40px;flex:1;max-width:420px;height:34px;display:flex;align-items:center;background:var(--aside-bg);border:1px solid var(--border);border-radius:17px;padding:0 14px}
.top-search .si{color:var(--muted);margin-right:8px}
.top-search input{border:none;background:transparent;outline:none;font-size:13px;flex:1;color:var(--text)}
.top-actions{margin-left:auto;display:flex;align-items:center;gap:20px}
.top-actions a{color:var(--nav);font-size:14px}
.top-actions a.login{color:var(--primary);font-weight:500}

/* 三栏布局：左导航贴左 + 中内容 + 右目录 */
.layout{display:flex;align-items:flex-start;min-height:calc(100vh - 65px)}

/* 左侧导航（贴左）*/
.sidebar{width:248px;flex-shrink:0;background:var(--aside-bg);border-right:1px solid var(--border);padding:20px 0;position:sticky;top:65px;height:calc(100vh - 65px);overflow:auto}
.nav-group{margin-bottom:4px}
.nav-title{font-size:11px;font-weight:700;color:var(--muted);padding:16px 24px 6px;letter-spacing:1.5px;text-transform:uppercase}
.sidebar > .nav-group > a{display:block;padding:10px 22px 10px 21px;margin:1px 8px;border-radius:6px;color:var(--text);font-size:14px;font-weight:600;border-left:3px solid transparent;transition:background .15s,color .15s;cursor:pointer}
.sidebar > .nav-group > a:hover{background:var(--hover);color:var(--primary)}
.sidebar > .nav-group > a.active{color:var(--primary);background:var(--primary-bg);border-left-color:var(--primary);font-weight:700}
.nav-sub{padding:4px 0 8px 8px;background:var(--primary-bg);border-left:3px solid var(--primary);margin:0 8px;border-radius:0 6px 6px 0}
.nav-sub li a{display:block;padding:7px 16px 7px 18px;color:var(--nav);font-size:13px;font-weight:400;border-radius:6px;transition:background .15s,color .15s}
.nav-sub li a:hover{color:var(--primary);background:rgba(24,113,255,.08)}
.nav-sub li a.active{color:var(--primary);font-weight:600;background:rgba(24,113,255,.14)}

/* 中间内容 */
.main{flex:1;min-width:0;padding:32px 40px;display:flex;justify-content:center}
.content-row{display:flex;gap:40px;align-items:flex-start;max-width:1100px;width:100%}
.article-col{flex:1;min-width:0;max-width:820px}
.crumb{font-size:13px;color:var(--muted);margin-bottom:18px}.crumb a{color:var(--muted)}.crumb a:hover{color:var(--primary)}
.article h1{font-size:26px;margin-bottom:6px;font-weight:600;color:var(--text);scroll-margin-top:85px}
.meta{font-size:13px;color:var(--muted);margin-bottom:22px}
.lead{background:var(--primary-bg);border-left:3px solid var(--primary);padding:14px 16px;border-radius:0 4px 4px 0;margin-bottom:30px;color:#334155}
.article h2{font-size:20px;margin:36px 0 14px;padding-bottom:10px;border-bottom:1px solid var(--border);font-weight:600;color:var(--text);scroll-margin-top:85px}
.article h3{font-size:16px;margin:22px 0 10px;font-weight:600;color:var(--text)}
.article p{margin:11px 0;color:#3f3f46}.article ol{margin:11px 0 11px 22px}.article li{margin:7px 0;color:#3f3f46}
.step{background:#fafbfc;border:1px solid var(--border);border-radius:6px;padding:6px 22px 18px;margin:18px 0}
.step h3{color:var(--primary);margin-top:16px}
table{width:100%;border-collapse:collapse;margin:14px 0;font-size:13px}
th,td{border:1px solid var(--border);padding:10px 12px;text-align:left;vertical-align:top}
th{background:#fafafa;font-weight:600}
.tip{background:var(--primary-bg);border-radius:4px;padding:10px 14px;margin:12px 0;font-size:13px;color:#334155}
.warn{background:var(--warn-bg);border:1px solid var(--warn-border);border-radius:4px;padding:10px 14px;margin:12px 0;font-size:13px}
.flow{background:#1f2329;color:#9ece6a;border-radius:4px;padding:12px 16px;font-family:Menlo,Consolas,monospace;font-size:13px;overflow-x:auto;margin:12px 0;white-space:pre}
.more{background:#fafbfc;border:1px solid var(--border);border-radius:6px;padding:18px 22px;margin-top:32px;scroll-margin-top:85px}
.more h3{margin-top:0}.more a{display:inline-block;margin:7px 20px 7px 0}
.shot{border:1px dashed var(--border);border-radius:4px;padding:26px;text-align:center;color:var(--muted);font-size:13px;margin:12px 0;background:#fcfcfd}
.helpful{text-align:center;color:var(--muted);font-size:13px;padding:26px 0 4px;border-top:1px solid var(--border);margin-top:30px}

/* 右侧文章目录 TOC */
.toc{width:190px;flex-shrink:0;position:sticky;top:85px;font-size:13px;max-height:calc(100vh - 100px);overflow:auto}
.toc-title{font-size:12px;font-weight:600;color:var(--title);margin-bottom:12px;letter-spacing:.5px}
.toc a{display:block;padding:5px 0 5px 12px;color:var(--nav);border-left:2px solid var(--border);line-height:1.5}
.toc a:hover{color:var(--primary);border-left-color:var(--primary)}

.footer{text-align:center;color:var(--muted);font-size:13px;padding:26px;border-top:1px solid var(--border);background:var(--aside-bg)}
@media(max-width:1200px){.toc{display:none}}
@media(max-width:900px){.layout{flex-direction:column}.sidebar{width:100%;position:static;height:auto;border-right:none;border-bottom:1px solid var(--border)}.main{padding:22px}.top-search{display:none}}

/* 截图：有图/无图降级 */
.shot-img{padding:0;border-style:solid;border-color:var(--border);background:none}
.shot-img img{display:block;width:100%;height:auto;border-radius:6px}
.shot-empty{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:7px;min-height:120px;background:repeating-linear-gradient(45deg,#f6f6f7,#f6f6f7 12px,#f1f1f3 12px,#f1f1f3 24px)}
.shot-empty .shot-num{display:inline-flex;align-items:center;justify-content:center;width:30px;height:30px;border-radius:50%;background:var(--primary);color:#fff;font-weight:600;font-size:13px}
.shot-empty .shot-label{color:var(--title);font-size:14px;font-weight:500}
.shot-empty .shot-file{color:var(--muted);font-size:12px;font-family:ui-monospace,Menlo,monospace}

/* 图片灯箱（点击放大 + 缩放 + 说明）*/
.shot-img img{cursor:zoom-in}
.lightbox-overlay{position:fixed;inset:0;background:rgba(0,0,0,.88);display:none;flex-direction:column;align-items:center;justify-content:center;z-index:9999;padding:24px;cursor:zoom-out}
.lightbox-overlay.active{display:flex}
.lightbox-bar{display:flex;gap:10px;margin-bottom:12px}
.lightbox-btn{background:rgba(255,255,255,.15);color:#fff;border:none;width:40px;height:40px;border-radius:50%;font-size:18px;line-height:1;cursor:pointer}
.lightbox-btn:hover{background:rgba(255,255,255,.3)}
.lightbox-overlay img{max-width:92vw;max-height:76vh;transition:transform .12s;transform-origin:center center;cursor:grab}
.lightbox-caption{color:rgba(255,255,255,.92);font-size:14px;margin-top:12px;text-align:center;max-width:90vw;line-height:1.6}