:root{
  --ink:#0F172A; --muted:#4A5875; --bg:#F7F8FC; --card:#FFFFFF; --line:#E2E6F0;
  --accent:#4338CA; --accent-2:#312E81; --soft:#EEF0FF; --teal:#0F766E; --warm:#B45309;
  --shadow:0 12px 32px rgba(15,23,42,.07);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;min-height:100vh;display:flex;flex-direction:column;background:var(--bg);color:var(--ink);
  font:17px/1.68 ui-sans-serif,-apple-system,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  -webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
main{flex:1 0 auto}
h1,h2,h3{font-family:"Iowan Old Style","Palatino Linotype",Palatino,Georgia,serif;line-height:1.16;
  letter-spacing:-.012em;color:var(--ink)}
h1{font-size:clamp(2.05rem,3.9vw,3.05rem);margin:0 0 18px;font-weight:700}
h2{font-size:clamp(1.5rem,2.4vw,1.95rem);margin:54px 0 16px;font-weight:700;scroll-margin-top:24px}
h3{font-size:1.16rem;margin:30px 0 8px;font-weight:700}
p{margin:0 0 18px;max-width:none;color:var(--ink)}
ul,ol{margin:0 0 22px;padding-left:22px;max-width:none}
li{margin:0 0 8px}
a{color:var(--accent);text-decoration:underline;text-decoration-thickness:1px;text-underline-offset:3px}
a:hover{color:var(--accent-2)}
a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid #6366F1;outline-offset:2px;border-radius:8px}
.wrap{width:min(1080px,100% - 40px);margin:0 auto}
.skip{position:fixed;left:12px;top:-72px;background:#fff;padding:12px 16px;z-index:40;
  border-radius:10px;box-shadow:var(--shadow);font-weight:700;text-decoration:none}
.skip:focus{top:12px}
/* 导航 */
.nav{background:#fff;border-bottom:1px solid var(--line)}
.nav .wrap{display:flex;align-items:center;gap:24px;padding:14px 0;flex-wrap:nowrap}
.brand{display:flex;align-items:center;gap:10px;font-weight:800;font-size:1.04rem;color:var(--ink);
  text-decoration:none;white-space:nowrap}
.brand svg{width:30px;height:30px;display:block}
.brand:hover{color:var(--ink)}
.nav-links{display:flex;align-items:center;gap:24px;margin-left:auto;overflow-x:auto;scrollbar-width:thin}
.nav-links a{font-size:.95rem;font-weight:600;color:var(--muted);text-decoration:none;white-space:nowrap;
  padding:6px 0;border-bottom:2px solid transparent}
.nav-links a:hover{color:var(--accent-2)}
.nav-links a.on{color:var(--accent);border-bottom-color:var(--accent)}
/* Hero */
/* Hero：copy 与正文同轴（660），插画占右侧 380 列，页面左/右外边线全站统一 */
.hero{background:linear-gradient(180deg,#FFFFFF 0%,#F2F3FB 100%);border-bottom:1px solid var(--line);
  padding-top:64px}
.hero-in{display:grid;grid-template-columns:minmax(0,660px) 380px;gap:40px;justify-content:space-between;
  align-items:center;padding:0 0 64px}
.hero-copy{min-width:0}
.kicker{margin:0 0 16px;font-size:.8rem;font-weight:800;letter-spacing:.09em;text-transform:uppercase;
  color:var(--teal)}
.lede{font-size:1.14rem;color:var(--muted);max-width:56ch}
.hero-cta{display:flex;flex-wrap:wrap;gap:16px;margin:26px 0 16px}
.hero-note{margin:0;font-size:.86rem;color:var(--muted);max-width:44ch}
.hero-meta{margin:22px 0 0;font-size:.86rem;color:var(--muted)}
.hero-art img{width:100%;height:auto;display:block;border-radius:24px;box-shadow:var(--shadow)}
.hero-topic .hero-in{padding:0 0 56px}
.hero-topic h1{font-size:clamp(1.9rem,3.3vw,2.7rem)}
.hero-topic .lede{font-size:1.08rem;max-width:52ch}
.hero-topic .hero-art img{border-radius:22px}
.btn{display:inline-flex;align-items:center;justify-content:center;min-height:46px;padding:12px 22px;
  border-radius:999px;background:var(--accent);color:#fff;font-weight:700;font-size:.97rem;
  text-decoration:none;border:1px solid var(--accent);transition:background-color .18s,transform .12s}
.btn:hover{background:var(--accent-2);color:#fff}
.btn:active{transform:scale(.985)}
.btn.ghost{background:#fff;color:var(--accent);border-color:#C7CBF5}
.btn.ghost:hover{background:var(--soft);color:var(--accent-2)}
/* 页面主体：正文 700 + 右栏 300，两者都落在 1080 网格上（不再右半边空一片） */
.page{padding:48px 0 64px}
.layout{display:grid;grid-template-columns:minmax(0,700px) 300px;gap:80px;
  justify-content:space-between;align-items:start}
.article{min-width:0}
.page-head{max-width:700px;margin:0 0 28px}
.page-head .lede{font-size:1.08rem;max-width:56ch}
.body{max-width:700px}
.page .wrap > .page-head,.page .wrap > .body{margin-left:auto;margin-right:auto}
.body > h2:first-child{margin-top:0}
.rail{position:sticky;top:24px;align-self:start;font-size:.9rem}
.tocbox{background:#fff;border:1px solid var(--line);border-radius:16px;padding:18px 20px 10px}
.tocbox .eyebrow{display:block;font-size:.73rem;font-weight:800;letter-spacing:.09em;text-transform:uppercase;
  color:var(--muted);margin:0 0 8px}
.tocbox ol{list-style:none;margin:0;padding:0;max-width:none}
.tocbox li{margin:0}
.tocbox a{display:block;padding:8px 0;font-size:.89rem;line-height:1.42;color:var(--muted);
  text-decoration:none;border-bottom:1px solid #EFF1F8}
.tocbox li:last-child a{border-bottom:0}
.tocbox a:hover{color:var(--accent)}
.rail-card{margin-top:16px;background:linear-gradient(160deg,#EEF0FF 0%,#F7F8FC 100%);
  border:1px solid #D7DAF8;border-radius:16px;padding:18px 20px}
.rail-card strong{display:block;font-size:.94rem;margin-bottom:6px}
.rail-card p{margin:0 0 10px;font-size:.85rem;color:var(--muted);line-height:1.55}
.rail-card a{font-size:.85rem;font-weight:700}
.toc-m{display:none;margin:0 0 24px;border:1px solid var(--line);border-radius:14px;background:#fff}
.toc-m summary{cursor:pointer;list-style:none;padding:15px 18px;font-weight:700;font-size:.94rem;
  display:flex;align-items:center;justify-content:space-between;gap:12px}
.toc-m summary::-webkit-details-marker{display:none}
.toc-m summary::after{content:"+";color:var(--accent);font-weight:800}
.toc-m[open] summary::after{content:"\2212"}
.toc-m ol{margin:0;padding:0 18px 14px 36px;max-width:none;font-size:.94rem}
.toc-m li{margin:0 0 6px}
.callout{background:var(--soft);border:1px solid #D7DAF8;border-left:5px solid var(--accent);
  border-radius:14px;padding:20px 22px;margin:24px 0}
.callout strong{display:block;margin-bottom:6px}
.callout p:last-child{margin-bottom:0}
.tbl-wrap{overflow-x:auto;margin:24px 0;border:1px solid var(--line);border-radius:16px;background:#fff}
table{width:100%;border-collapse:collapse;min-width:640px;font-size:.95rem}
caption{caption-side:top;text-align:left;padding:14px 18px 0;font-size:.86rem;color:var(--muted)}
th,td{padding:12px 16px;text-align:left;border-bottom:1px solid var(--line);vertical-align:top}
th{background:#F4F5FB;font-size:.82rem;letter-spacing:.04em;text-transform:uppercase;color:var(--muted);
  white-space:nowrap}
tbody tr:last-child td{border-bottom:0}
td code,code{background:#F1F2F9;border-radius:6px;padding:2px 6px;font-size:.88em;
  font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace}
td a{white-space:nowrap}
/* 卡片阵列 */
.cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:20px;margin:24px 0}
.card{display:flex;flex-direction:column;background:#fff;border:1px solid var(--line);border-radius:18px;
  padding:22px;text-decoration:none;color:var(--ink);box-shadow:0 2px 0 rgba(15,23,42,.02);
  transition:transform .16s,box-shadow .16s,border-color .16s}
.card:hover{transform:translateY(-2px);box-shadow:var(--shadow);border-color:#C7CBF5;color:var(--ink)}
.card .tag{font-size:.74rem;font-weight:800;letter-spacing:.08em;text-transform:uppercase;color:var(--teal);
  margin-bottom:8px}
.card h3{margin:0 0 8px;font-size:1.08rem}
.card p{margin:0;font-size:.93rem;color:var(--muted);max-width:none}
.card .go{margin-top:auto;padding-top:14px;font-size:.86rem;font-weight:700;color:var(--accent)}
/* 图：SVG 自带白卡（含圆角描边），容器不再套第二层边框 */
figure.ig{margin:34px 0;max-width:100%}
.ig-scroll{overflow-x:auto;-webkit-overflow-scrolling:touch}
.ig-scroll img{width:100%;min-width:560px;height:auto;display:block;border-radius:16px}
figure.ig figcaption{font-size:.82rem;color:var(--muted);margin-top:10px;max-width:68ch;line-height:1.6}
.fig-hint{display:none;margin:6px 0 0;font-size:.8rem;color:var(--muted)}
/* 复制块 */
.copyblock{margin:20px 0;border:1px solid var(--line);border-radius:14px;background:#fff;overflow:hidden}
.copyblock .cb-head{display:flex;align-items:center;justify-content:space-between;gap:16px;
  padding:12px 16px;background:#F4F5FB;border-bottom:1px solid var(--line)}
.copyblock .cb-head span{font-size:.8rem;font-weight:800;letter-spacing:.06em;text-transform:uppercase;
  color:var(--muted)}
.copyblock pre{margin:0;padding:16px;white-space:pre-wrap;word-break:break-word;font-size:.9rem;
  font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;color:#1F2937}
.cp-btn{display:inline-grid;place-items:center;min-width:104px;min-height:34px;padding:6px 14px;
  border:1px solid #C7CBF5;border-radius:999px;background:#fff;color:var(--accent);font-weight:700;
  font-size:.82rem;cursor:pointer;font-family:inherit}
.cp-btn:hover{background:var(--soft)}
.cp-face{grid-area:1/1;transition:opacity .16s}
.cp-ok{opacity:0}
.cp-btn.on .cp-face{opacity:0}
.cp-btn.on .cp-ok{opacity:1;color:var(--teal)}
/* FAQ：一整块列表 + 分隔线（六块独立白卡视觉噪音太大） */
.faq-list{margin:8px 0 0;background:#fff;border:1px solid var(--line);border-radius:16px;overflow:hidden}
.faq{margin:0;border-top:1px solid var(--line);padding:0 20px}
.faq:first-child{border-top:0}
.faq summary{cursor:pointer;font-weight:700;padding:18px 0;list-style:none;display:flex;gap:12px;
  align-items:flex-start}
.faq summary::-webkit-details-marker{display:none}
.faq summary::before{content:"+";color:var(--accent);font-weight:800;line-height:1.3}
.faq[open] summary::before{content:"\2212"}
.faq[open]{background:#FBFBFE}
.faq .faq-a{padding:0 0 18px 22px;color:var(--muted)}
.faq .faq-a p{margin:0}
/* 相关链接 */
.related{margin:44px 0 0;padding:24px 26px;border-radius:18px;background:#fff;border:1px solid var(--line)}
.related strong{display:block;margin-bottom:12px;font-size:.82rem;letter-spacing:.08em;text-transform:uppercase;
  color:var(--muted)}
.related ul{margin:0;padding-left:20px;columns:2;column-gap:36px}
.related li{break-inside:avoid}
/* 页脚 */
footer.site{background:#1E1B4B;color:#C7D2FE;margin-top:56px;padding:44px 0 28px}
footer.site .cols{display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr;gap:32px;
  width:min(1080px,100% - 40px);margin:0 auto}
footer.site strong{color:#fff;display:block;margin-bottom:12px;font-size:.85rem;letter-spacing:.06em;
  text-transform:uppercase}
footer.site p{margin:0;font-size:.9rem;color:#A5B4FC;max-width:34ch}
footer.site a{display:block;color:#C7D2FE;text-decoration:none;font-size:.92rem;padding:5px 0}
footer.site a:hover{color:#fff;text-decoration:underline}
footer.site .legal{width:min(1080px,100% - 40px);margin:28px auto 0;padding-top:18px;
  border-top:1px solid rgba(199,210,254,.18);font-size:.82rem;color:#A5B4FC}
footer.site .legal a{display:inline;padding:0}
/* 404 */
.nf{padding:72px 0;text-align:center}
/* 响应式：1040 收右栏（移动端给 <details> 目录），900 导航换行，620 单列 */
@media (max-width:1040px){
  .layout{grid-template-columns:minmax(0,1fr);gap:0}
  .article{width:100%;max-width:700px;margin:0 auto}
  .rail{display:none}
  .toc-m{display:block}
  .hero-in{grid-template-columns:1fr;gap:32px;justify-items:center}
  .hero-copy{width:100%;max-width:700px}
  .hero-art{width:100%;max-width:520px;margin:0}
}
@media (max-width:900px){
  .hero{padding-top:44px}
  .hero-in{padding:0 0 48px}
  .hero-topic .hero-in{padding:0 0 44px;gap:28px}
  .nav .wrap{flex-wrap:wrap;gap:12px}
  .nav-links{width:100%;margin-left:0;gap:20px;padding-bottom:4px}
  footer.site .cols{grid-template-columns:1fr 1fr;gap:24px}
}
@media (max-width:660px){
  .fig-hint{display:block}
  .ig-wrap{position:relative}
  /* 横滑提示：右缘圆形箭头（fade 会压住图中文字，只用角标） */
  .ig-wrap::after{content:"\203A";position:absolute;top:50%;right:6px;transform:translateY(-50%);
    width:30px;height:30px;border-radius:50%;background:rgba(15,23,42,.6);color:#fff;text-align:center;
    font:700 20px/30px system-ui,sans-serif;pointer-events:none}
  /* 表格窄屏堆叠成行卡片：3 列表格在 390 视口横滑会整列藏掉（30.2 宁横滑不压碎，但能堆叠就堆叠） */
  .tbl-wrap{overflow:hidden}
  table{min-width:0;font-size:.95rem}
  thead{display:none}
  tbody,tr,td{display:block}
  tbody tr{padding:16px;border-bottom:1px solid var(--line)}
  tbody tr:last-child{border-bottom:0}
  td{padding:0;border:0}
  td + td{margin-top:8px}
  td::before{content:attr(data-label);display:block;font-size:.7rem;font-weight:800;letter-spacing:.07em;
    text-transform:uppercase;color:var(--muted);margin-bottom:2px}
  td.row-key{font-weight:700;font-size:1.02rem}
  td.row-key::before{display:none}
  td.cell-short{display:flex;gap:10px;align-items:baseline;margin-top:6px}
  td.cell-short::before{flex:0 0 auto;margin:0}
  caption{padding:14px 16px 0}
}
@media (max-width:620px){
  body{font-size:16.5px}
  .wrap{width:min(1080px,100% - 32px)}
  .hero{padding-top:30px}
  .hero-in,.hero-topic .hero-in{padding:0 0 40px;gap:24px}
  .hero-art{max-width:none}
  .hero-cta .btn{flex:1 1 100%}
  .page{padding:32px 0 44px}
  h2{margin-top:44px}
  .related ul{columns:1}
  footer.site .cols{grid-template-columns:1fr}
}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation-duration:.001ms!important;animation-iteration-count:1!important;
    transition-duration:.001ms!important}
  .card:hover{transform:none}
  .btn:active{transform:none}
}