/* bilupai.com 设计系统 · 权威档案方向
   骨架在本站内定稿一次，后续所有页面复用；新增区块必须先在这里加样式再使用。 */

:root{
  --paper:#eceff3;
  --surface:#ffffff;
  --ink:#1b1f24;
  --muted:#5d6672;
  --line:#d3d9e0;
  --line-soft:#e4e8ed;
  --brick:#b0432b;
  --brick-deep:#8c3421;
  --brick-tint:#f7ece8;
  --slate:#39404a;
  --warn-bg:#f6efe9;
  --warn-line:#e0cbbb;
  --ok:#2c6a56;
  --ok-bg:#e8f0ed;
  --display:"Archivo",system-ui,-apple-system,"Segoe UI",sans-serif;
  --body:system-ui,-apple-system,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
}

*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{margin:0;background:var(--paper);color:var(--ink);font:15px/1.7 var(--body)}
a{color:inherit;text-decoration:none}
img{max-width:100%;height:auto}
hr{height:1px;margin:32px 0;border:0;background:var(--line)}

.shell{width:min(1180px,calc(100% - 40px));margin:0 auto}
.shell-narrow{width:min(760px,calc(100% - 40px));margin:0 auto}

.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip-path:inset(50%);white-space:nowrap}
.skip-link{position:absolute;inset-block-start:-60px;inset-inline-start:12px;z-index:20;padding:10px 16px;background:var(--ink);color:#fff;font-size:14px}
.skip-link:focus{inset-block-start:8px}

/* ---------- 顶部 utility 条 ---------- */
.util{background:var(--slate);color:#c9d0d8;font-size:12px}
.util .shell{display:flex;align-items:center;justify-content:space-between;height:36px}
.util-note{margin:0}
.lang{display:flex;gap:14px}
.lang a{padding:2px 0;border-bottom:1px solid transparent}
.lang a[aria-current="true"]{color:#fff;border-bottom-color:var(--brick)}

/* ---------- 刊头与导航 ---------- */
.masthead{background:var(--surface);border-bottom:1px solid var(--line)}
.masthead .shell{display:flex;align-items:center;justify-content:space-between;height:66px}
.wordmark{display:flex;align-items:center;gap:11px;font-family:var(--display);font-weight:800;font-size:20px;letter-spacing:-.02em}
.wordmark-seal{display:block;width:26px;height:26px}
.nav{display:flex;gap:26px;font-size:14px;color:var(--slate)}
.nav a{position:relative;padding:6px 0;border-bottom:2px solid transparent}
.nav a::after{content:"";position:absolute;left:0;right:0;top:50%;transform:translateY(-50%);height:44px}
.nav a:hover,.nav a[aria-current="page"]{border-bottom-color:var(--brick)}

/* ---------- 面包屑 ---------- */
.crumb{padding:14px 0;font-size:13px;color:var(--muted)}
.crumb ol{display:flex;flex-wrap:wrap;gap:8px;margin:0;padding:0;list-style:none}
.crumb li::after{content:"›";margin-inline-start:8px;color:var(--line)}
.crumb li:last-child::after{content:""}
.crumb a{border-bottom:1px solid var(--line)}

/* ---------- 首页 hero ---------- */
.hero{display:grid;grid-template-columns:1fr 348px;gap:40px;padding:44px 0 34px;align-items:start}
.hero-doc{min-width:0}
.kicker{display:inline-block;padding:4px 10px;background:var(--brick);color:#fff;font-family:var(--display);font-size:11px;font-weight:600;letter-spacing:.14em}
.hero h1{margin:20px 0 16px;font-size:clamp(30px,4.1vw,50px);line-height:1.14;letter-spacing:-.03em;font-weight:800;max-width:16em}
.lead{margin:0 0 22px;max-width:44em;color:var(--muted);font-size:17px}
.byline{display:flex;flex-wrap:wrap;align-items:center;gap:10px;padding-top:16px;border-top:1px solid var(--line);font-size:13px;color:var(--muted)}
.byline-org{color:var(--ink);font-weight:600}
.byline-sep{color:var(--line)}
.byline-link{border-bottom:1px solid var(--line);color:var(--slate)}
.hero-act{margin-top:24px;display:inline-flex;align-items:center;min-height:44px;padding:12px 20px;border:1px solid var(--slate);color:var(--slate);font-size:14px;font-weight:600}
.hero-act:hover{background:var(--slate);color:#fff}

/* ---------- 首屏转化卡（邀请码位） ---------- */
.convert{background:var(--surface);border:1px solid var(--line);border-top:3px solid var(--brick);padding:24px}
.convert-head{margin:0 0 16px;font-family:var(--display);font-size:12px;font-weight:600;letter-spacing:.13em;color:var(--muted)}
.code-slot{display:flex;align-items:stretch;border:1px solid var(--line)}
.code-value{flex:1;min-width:0;display:flex;align-items:center;padding:0 14px;background:#f7f9fb;font-family:var(--display);font-size:22px;font-weight:800;letter-spacing:.08em}
.code-value[data-empty="true"]{font-size:15px;font-weight:600;color:var(--muted);letter-spacing:0}
.code-copy{min-height:44px;padding:12px 16px;border:0;border-left:1px solid var(--line);background:var(--brick);color:#fff;font-family:var(--body);font-size:14px;font-weight:600;cursor:pointer}
.code-copy:hover{background:var(--brick-deep)}
.code-hint{margin:9px 0 0;min-height:1.5em;font-size:12.5px;color:var(--muted)}
.benefit{margin:18px 0 0;font-size:15px;line-height:1.6}
.benefit b{font-weight:700}
.benefit-star{white-space:nowrap}
.benefit-note{margin:8px 0 0;font-size:12px;color:var(--muted)}
.convert-disclosure{margin:16px 0 0;padding-top:14px;border-top:1px solid var(--line-soft);font-size:12px;color:var(--muted)}

/* ---------- 风险条 ---------- */
.risk{background:var(--warn-bg);border-top:1px solid var(--warn-line);border-bottom:1px solid var(--warn-line)}
.risk .shell{padding:14px 0;font-size:13px;color:var(--slate)}
.risk p{margin:0}
.risk b{color:var(--brick-deep)}

/* ---------- 旅程轨 ---------- */
.rail{display:grid;grid-template-columns:repeat(4,1fr);gap:1px;background:var(--line);border-bottom:1px solid var(--line)}
.rail-step{display:block;background:var(--paper);padding:20px 22px 24px}
.rail-step:hover{background:var(--surface)}
.rail-num{margin:0;font-family:var(--display);font-size:12px;font-weight:600;letter-spacing:.12em;color:var(--brick)}
.rail-step h2{margin:8px 0 6px;font-size:17px;font-weight:700;letter-spacing:-.01em}
.rail-step p{margin:0;font-size:13px;color:var(--muted)}

/* ---------- 通用区块 ---------- */
.section{padding:44px 0}
.section-alt{background:var(--surface);border-block:1px solid var(--line)}
.section-head{display:flex;align-items:baseline;justify-content:space-between;gap:16px;margin:0 0 22px;padding-bottom:12px;border-bottom:1px solid var(--line)}
.section-head h2{margin:0;font-size:22px;letter-spacing:-.02em}
.section-more{font-size:13px;color:var(--slate);border-bottom:1px solid var(--line)}
.section-note{margin:0 0 22px;max-width:52em;color:var(--muted);font-size:14px}

.card-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
.card-grid-2{grid-template-columns:repeat(2,1fr)}
.card{display:flex;flex-direction:column;padding:22px;background:var(--surface);border:1px solid var(--line)}
.card:hover{border-color:var(--slate)}
.card-tag{font-family:var(--display);font-size:11px;font-weight:600;letter-spacing:.1em;color:var(--brick)}
.card h3{margin:14px 0 8px;font-size:18px;line-height:1.35}
.card p{margin:0;color:var(--muted);font-size:13.5px}
.card-meta{margin:16px 0 0;padding-top:12px;border-top:1px solid var(--line-soft);font-size:12px;color:var(--muted)}

.index-columns{display:grid;grid-template-columns:repeat(3,1fr);gap:28px}
.index-col h3{margin:0 0 12px;padding-bottom:10px;border-bottom:1px solid var(--line);font-size:15px}
.list-plain{margin:0;padding:0;list-style:none}
.list-plain li{padding:7px 0;border-bottom:1px solid var(--line-soft);font-size:14px}
.list-plain li:last-child{border-bottom:0}
.list-plain a:hover{color:var(--brick-deep)}

/* ---------- 文章页 ---------- */
.article{padding:8px 0 56px}
.article-head{max-width:44em}
.article-head h1{margin:6px 0 14px;font-size:clamp(27px,3.4vw,40px);line-height:1.22;letter-spacing:-.025em}
.article-deck{margin:0 0 18px;color:var(--muted);font-size:17px}
.article-meta{display:flex;flex-wrap:wrap;align-items:center;gap:10px;padding:14px 0;border-block:1px solid var(--line);font-size:13px;color:var(--muted)}
.article-body{max-width:44em;margin-top:26px;font-size:16px}
.article-body h2{margin:40px 0 14px;font-size:24px;letter-spacing:-.02em;scroll-margin-top:20px}
.article-body h3{margin:28px 0 10px;font-size:18px}
.article-body h4{margin:22px 0 8px;font-size:15.5px;font-weight:700;color:var(--slate)}
.article-body p{margin:0 0 16px}
.article-body ul,.article-body ol{margin:0 0 16px;padding-inline-start:22px}
.article-body li{margin:0 0 8px}
.article-body strong{font-weight:700}
.article-body a{border-bottom:1px solid var(--brick);color:var(--brick-deep)}

.toc{margin:0 0 8px;padding:18px 20px;background:var(--surface);border:1px solid var(--line)}
.toc-head{margin:0 0 10px;font-family:var(--display);font-size:11px;font-weight:600;letter-spacing:.12em;color:var(--muted)}
.toc-list{margin:0;padding:0;list-style:none;column-gap:28px}
.toc-list li{padding:4px 0;font-size:14px;line-height:1.5;break-inside:avoid}
.toc-list a{border-bottom:1px solid var(--line)}
@media(min-width:700px){.toc-list{columns:2}}

.answer-box{margin:0 0 20px;padding:16px 18px;background:var(--brick-tint);border-inline-start:3px solid var(--brick);font-size:15.5px}
.answer-box p{margin:0}
.callout{margin:22px 0;padding:16px 18px;border:1px solid var(--line);background:var(--surface);font-size:14.5px}
.callout p{margin:0 0 8px}
.callout p:last-child{margin:0}
.callout-warn{background:var(--warn-bg);border-color:var(--warn-line)}
.callout-ok{background:var(--ok-bg);border-color:#c2d6ce}
.callout-head{margin:0 0 8px;font-weight:700;font-size:14px}

.table-wrap{margin:22px 0;overflow-x:auto}
.data-table{width:100%;border-collapse:collapse;font-size:14px}
.data-table th,.data-table td{padding:10px 12px;border:1px solid var(--line);text-align:start;vertical-align:top}
.data-table th{background:var(--surface);font-weight:700}
.data-table caption{margin-bottom:8px;color:var(--muted);font-size:12.5px;text-align:start}

.faq{margin:34px 0 0}
.faq-item{padding:16px 0;border-top:1px solid var(--line)}
.faq-q{margin:0 0 8px;font-size:17px;font-weight:700}
.faq-a{margin:0;color:var(--slate)}

.figure{margin:24px 0}
.figure img{display:block;width:100%;height:auto;border:1px solid var(--line)}
.figure-cap{margin:8px 0 0;color:var(--muted);font-size:12.5px;line-height:1.65}
.article-cover{margin:0 0 24px}
.article-cover img{display:block;width:100%;height:auto;border:1px solid var(--line)}

.prevnext{display:grid;grid-template-columns:repeat(2,1fr);gap:16px;margin-top:40px;padding-top:24px;border-top:1px solid var(--line)}
.prevnext a{padding:16px 18px;background:var(--surface);border:1px solid var(--line);font-size:14px}
.prevnext span{display:block;margin-bottom:6px;font-family:var(--display);font-size:11px;letter-spacing:.1em;color:var(--muted)}

/* ---------- 工具页 ---------- */
.tool{padding:8px 0 56px}
.tool-panel{margin:24px 0;padding:26px;background:var(--slate);color:#e8edf2;border-top:3px solid var(--brick)}
.tool-field{margin:0 0 16px}
.tool-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:0 18px}
.tool-label{display:block;margin-bottom:7px;font-size:13px;color:#b9c3cd}
.tool-hint{margin:6px 0 0;font-size:12px;color:#8d97a2}
@media(max-width:560px){.tool-grid{grid-template-columns:1fr}}
.tool-input,.tool-select{width:100%;padding:11px 12px;background:#2c333c;border:1px solid #4a525d;color:#fff;font:15px var(--body)}
.tool-input:focus,.tool-select:focus{outline:2px solid var(--brick);outline-offset:0}
.tool-run{min-height:44px;padding:12px 22px;border:0;background:var(--brick);color:#fff;font:600 14px var(--body);cursor:pointer}
.tool-run:hover{background:var(--brick-deep)}
.tool-result{margin-top:22px;padding-top:20px;border-top:1px solid #4a525d}
.result-big{margin:0;font-family:var(--display);font-size:clamp(26px,4vw,38px);font-weight:800;line-height:1.2;color:#fff}
.result-note{margin:10px 0 0;font-size:13.5px;color:#b9c3cd}
.result-list{margin:14px 0 0;padding-inline-start:20px;font-size:14px;color:#d3dae1}
.result-list li{margin:0 0 7px}
.result-ok{color:#8fe0c4}
.result-warn{color:#f0c88a}
.result-no{color:#f0a08a}
.result-kv{margin:16px 0 0;padding-top:14px;border-top:1px solid #4a525d;font-size:14px;color:#d3dae1}
.result-kv dt{margin:0 0 4px;font-size:12px;letter-spacing:.06em;color:#8d97a2}
.result-kv dd{margin:0 0 14px}
.result-kv dd:last-child{margin-bottom:0}
.tool-stamp{margin:12px 0 0;font-size:12px;color:#8d97a2}
.tool-guide{margin-top:32px;padding:0;border:1px solid var(--line);background:var(--surface)}
.tool-guide>summary{padding:16px 20px;font-weight:700;font-size:15px;cursor:pointer}
.guide-item{padding:0 20px}
.guide-item h3{margin:0 0 8px;font-size:16px}
.guide-item p{margin:0 0 16px;color:var(--slate);font-size:14.5px}

/* ---------- 页脚 ---------- */
.site-footer{margin-top:0;padding:40px 0 34px;background:var(--slate);color:#b9c3cd;font-size:13.5px}
.foot-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr;gap:28px}
.foot-brand{font-family:var(--display);font-weight:800;font-size:18px;color:#fff;display:flex;align-items:center;gap:10px}
.foot-about{margin:14px 0 0;max-width:30em}
.foot-head{margin:0 0 12px;font-family:var(--display);font-size:11px;font-weight:600;letter-spacing:.12em;color:#8d97a2}
.foot-links{margin:0;padding:0;list-style:none}
.foot-links li{margin:0 0 8px}
.foot-links a{display:inline-block;padding:3px 0}
.foot-links a:hover{color:#fff}
.foot-rss{border-bottom:1px solid #5a626c}
.foot-legal{margin:32px 0 0;padding-top:20px;border-top:1px solid #4a525d;font-size:12.5px;color:#8d97a2}
.foot-legal p{margin:0 0 7px}
.foot-legal a{border-bottom:1px solid #5a626c}

/* ---------- 响应式 ---------- */
@media(max-width:900px){
  .nav{gap:18px;font-size:13px}
  .hero{grid-template-columns:1fr;gap:26px;padding:30px 0 24px}
  .hero h1{margin:16px 0 12px}
  .lead{font-size:16px}
  .rail{grid-template-columns:1fr 1fr}
  .card-grid,.card-grid-2{grid-template-columns:1fr 1fr}
  .index-columns{grid-template-columns:1fr 1fr}
  .foot-grid{grid-template-columns:1fr 1fr}
}
@media(max-width:620px){
  .masthead .shell{height:auto;padding:12px 0;flex-direction:column;align-items:flex-start;gap:10px}
  .nav{flex-wrap:wrap;gap:14px}
  .card-grid,.card-grid-2{grid-template-columns:1fr}
  .index-columns{grid-template-columns:1fr}
  .prevnext{grid-template-columns:1fr}
  .foot-grid{grid-template-columns:1fr}
  .article-body{font-size:15.5px}
}
@media(max-width:420px){
  .shell,.shell-narrow{width:calc(100% - 28px)}
  .util{font-size:11.5px}
  .util .shell{height:auto;padding:6px 0;flex-direction:column;align-items:flex-start;gap:2px}
  .masthead .shell{padding:10px 0}
  .hero{padding:16px 0 16px;gap:18px}
  .kicker{padding:3px 9px;font-size:10.5px}
  .hero h1{margin:12px 0 10px;font-size:26px;line-height:1.18}
  .lead{margin-bottom:14px;font-size:15px;line-height:1.6}
  .byline{padding-top:12px;gap:8px;font-size:12.5px}
  .hero-act{margin-top:16px;padding:11px 16px}
  .convert{padding:18px}
  .convert-head{margin-bottom:12px}
  .code-value{font-size:19px}
  .code-copy{padding:12px}
  .code-hint{margin-top:7px}
  .benefit{margin-top:14px}
  .rail{grid-template-columns:1fr}
  .section{padding:32px 0}
  .tool-panel{padding:20px}
  .foot-links li{margin:0 0 4px}
  .foot-links a{padding:10px 0}
}