/* ============================================================
   亚文网官网 · 共享样式 /assets/site.css
   雾蓝基底 · 琥珀交互 · 玻璃层与实色层并置
   ============================================================ */

/* ---------- 1. Reset ---------- */
*,
*::before,
*::after{box-sizing:border-box;}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;}
body,h1,h2,h3,h4,h5,p,ul,ol,figure,blockquote,dl,dd{margin:0;}
ul,ol{padding:0;list-style:none;}
img,svg{max-width:100%;display:block;}
button{font:inherit;color:inherit;background:none;border:0;}
a{color:inherit;}
table{border-collapse:collapse;width:100%;}
[hidden]{display:none !important;}

/* ---------- 2. 设计令牌 ---------- */
:root{
  --mist:#EDF2F6;
  --ink:#22333E;
  --deep:#142129;
  --amber:#E8801F;
  --amber-deep:#9E4E0A;
  --silver:#F8FAFC;
  --line:#C3CDD4;
  --glass:rgba(255,255,255,.72);
  --teal:#0E8F8F;
  --muted:#556B7A;

  --font-sans:"Noto Sans SC","Source Han Sans SC","PingFang SC",system-ui,-apple-system,"Microsoft YaHei",sans-serif;
  --font-mono:"JetBrains Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;

  --r-lg:16px;
  --r-md:10px;
  --r-sm:6px;
  --shadow:0 1px 2px rgba(20,33,41,.05),0 26px 44px -34px rgba(20,33,41,.5);
  --ease:cubic-bezier(.22,.61,.36,1);
  --header-h:66px;
  --wrap:1320px;
  --gutter:clamp(1rem,4vw,2.75rem);
}

/* ---------- 3. 中文排版基底 ---------- */
body{
  font-family:var(--font-sans);
  font-size:17px;
  line-height:1.85;
  color:var(--ink);
  min-height:100vh;
  letter-spacing:.005em;
  background:
    radial-gradient(1100px 620px at 88% -12%,rgba(14,143,143,.07),transparent 62%),
    radial-gradient(900px 520px at -12% 18%,rgba(232,128,31,.065),transparent 64%),
    var(--mist);
  background-attachment:fixed;
}
h1,h2,h3,h4{line-height:1.22;color:var(--ink);font-weight:800;letter-spacing:-.01em;}
h1{font-weight:900;letter-spacing:-.02em;}
p{max-width:70ch;}
strong{font-weight:800;}
code,kbd,samp{font-family:var(--font-mono);font-size:.9em;}

a:focus-visible,
button:focus-visible,
[tabindex]:focus-visible{
  outline:2px solid var(--amber);
  outline-offset:2px;
  border-radius:var(--r-sm);
}

main{display:block;scroll-margin-top:calc(var(--header-h) + 18px);}

/* ---------- 4. 跳转与容器 ---------- */
.skip-link{
  position:absolute;
  top:-100px;
  left:var(--gutter);
  z-index:120;
  padding:.55rem 1rem;
  background:var(--deep);
  color:var(--silver);
  font-size:.85rem;
  font-weight:700;
  border-radius:0 0 var(--r-md) var(--r-md);
  text-decoration:none;
  transition:top .22s var(--ease);
}
.skip-link:focus{top:0;}

.wrap{width:min(var(--wrap),calc(100% - var(--gutter) * 2));margin-inline:auto;}
.wrap--narrow{width:min(920px,calc(100% - var(--gutter) * 2));margin-inline:auto;}

/* ---------- 5. 页头 ---------- */
.site-header{
  position:sticky;
  top:0;
  z-index:60;
  background:var(--glass);
  -webkit-backdrop-filter:blur(16px) saturate(1.25);
  backdrop-filter:blur(16px) saturate(1.25);
  border-bottom:1px solid var(--line);
}
.header-inner{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:clamp(.75rem,2vw,1.5rem);
  width:min(var(--wrap),calc(100% - var(--gutter) * 2));
  margin-inline:auto;
  min-height:var(--header-h);
  padding-block:.6rem;
}
.header-left{display:flex;align-items:center;gap:clamp(.6rem,1.6vw,1.15rem);min-width:0;}
.header-right{display:flex;align-items:center;justify-content:flex-end;gap:clamp(.5rem,1.2vw,1rem);min-width:0;}

.brand{display:flex;flex-direction:column;gap:.1rem;text-decoration:none;min-width:0;}
.brand__name{
  font-size:1.22rem;
  font-weight:900;
  line-height:1.1;
  letter-spacing:.02em;
  color:var(--ink);
}
.brand__line{
  font-size:.68rem;
  line-height:1.3;
  letter-spacing:.16em;
  color:var(--muted);
}
.brand:hover .brand__name{color:var(--amber-deep);}

.guide-entry{
  display:inline-flex;
  align-items:center;
  gap:.45rem;
  padding:.34rem .72rem;
  border:1px solid var(--line);
  border-radius:999px;
  background:rgba(255,255,255,.6);
  font-size:.8rem;
  font-weight:700;
  color:var(--ink);
  text-decoration:none;
  white-space:nowrap;
  transition:border-color .25s var(--ease),color .25s var(--ease),transform .25s var(--ease);
}
.guide-entry__dot{
  width:6px;height:6px;border-radius:50%;
  background:var(--amber);
  box-shadow:0 0 0 3px rgba(232,128,31,.18);
}
.guide-entry:hover{border-color:var(--amber);color:var(--amber-deep);transform:translateY(-1px);}

.site-nav{display:flex;align-items:center;}
.site-nav__list{display:flex;align-items:center;gap:clamp(.6rem,1.5vw,1.55rem);}
.site-nav__item{position:relative;}
.site-nav__link{
  position:relative;
  display:inline-block;
  padding:.4rem 0;
  font-size:.95rem;
  font-weight:600;
  color:var(--ink);
  text-decoration:none;
  white-space:nowrap;
  transition:color .22s var(--ease);
}
.site-nav__link::after{
  content:"";
  position:absolute;
  left:0;right:0;bottom:.06rem;
  height:2px;
  background:var(--amber);
  transform:scaleX(0);
  transform-origin:left center;
  transition:transform .26s var(--ease);
}
.site-nav__link:hover{color:var(--amber-deep);}
.site-nav__link:hover::after{transform:scaleX(1);}
.site-nav__link[aria-current="page"]{color:var(--amber-deep);font-weight:800;}
.site-nav__link[aria-current="page"]::after{transform:scaleX(1);}

.index-jump{
  display:inline-flex;
  align-items:baseline;
  gap:.4rem;
  max-width:172px;
  padding:.38rem .78rem;
  border:1px solid var(--line);
  border-radius:999px;
  background:rgba(255,255,255,.55);
  font-family:var(--font-mono);
  font-size:.7rem;
  letter-spacing:.04em;
  color:var(--ink);
  cursor:pointer;
  overflow:hidden;
  white-space:nowrap;
  transition:border-color .25s var(--ease),color .25s var(--ease),background .25s var(--ease);
}
.index-jump__label{font-family:var(--font-sans);font-weight:700;font-size:.78rem;}
.index-jump__hint{color:var(--muted);}
.index-jump:hover{border-color:var(--amber);color:var(--amber-deep);background:rgba(232,128,31,.08);}

.nav-toggle{
  display:none;
  align-items:center;
  gap:.5rem;
  padding:.42rem .78rem;
  border:1px solid var(--line);
  border-radius:999px;
  background:rgba(255,255,255,.6);
  font-size:.82rem;
  font-weight:700;
  color:var(--ink);
  cursor:pointer;
  transition:border-color .25s var(--ease),color .25s var(--ease);
}
.nav-toggle:hover{border-color:var(--amber);color:var(--amber-deep);}
.nav-toggle__bars{display:inline-flex;flex-direction:column;justify-content:center;gap:4px;width:16px;}
.nav-toggle__bars span{display:block;height:2px;border-radius:2px;background:currentColor;transition:transform .26s var(--ease),opacity .26s var(--ease);}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:first-child{transform:translateY(3px) rotate(45deg);}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:last-child{transform:translateY(-3px) rotate(-45deg);}

.scroll-progress{
  position:absolute;
  left:0;bottom:-1px;
  width:100%;height:2px;
  background:linear-gradient(90deg,var(--teal),var(--amber));
  transform:scaleX(0);
  transform-origin:0 50%;
  will-change:transform;
}

.nav-scrim{
  position:fixed;
  inset:0;
  z-index:50;
  background:rgba(20,33,41,.42);
  opacity:0;
  visibility:hidden;
  transition:opacity .3s var(--ease),visibility .3s var(--ease);
}
.nav-scrim[data-open]{opacity:1;visibility:visible;}

/* ---------- 6. 页脚 ---------- */
.site-footer{
  position:relative;
  margin-top:clamp(3rem,7vw,6rem);
  border-top:1px solid var(--line);
  background:linear-gradient(180deg,rgba(237,242,246,.4),#E3EAF0 78%);
  overflow:hidden;
}
.footer-inner{
  display:grid;
  grid-template-columns:1.25fr .85fr .85fr 1.5fr;
  gap:clamp(1.5rem,3.5vw,3rem);
  width:min(var(--wrap),calc(100% - var(--gutter) * 2));
  margin-inline:auto;
  padding-block:clamp(2.25rem,4.5vw,3.5rem) 1.75rem;
}
.footer-brand{display:flex;flex-direction:column;gap:.4rem;}
.footer-brand__name{font-size:1.35rem;font-weight:900;letter-spacing:.02em;color:var(--ink);}
.footer-brand__line{font-size:.78rem;letter-spacing:.14em;color:var(--muted);}
.footer-brand__icp{
  margin-top:.35rem;
  font-family:var(--font-mono);
  font-size:.74rem;
  color:var(--amber-deep);
  border-left:2px solid var(--amber);
  padding-left:.5rem;
}
.footer-col{display:flex;flex-direction:column;gap:.85rem;min-width:0;}
.footer-col__title{
  font-size:.74rem;
  font-weight:800;
  letter-spacing:.22em;
  color:var(--muted);
  padding-bottom:.5rem;
  border-bottom:1px solid var(--line);
}
.footer-list{display:flex;flex-direction:column;gap:.55rem;font-size:.9rem;}
.footer-list a{
  color:var(--ink);
  text-decoration:none;
  transition:color .22s var(--ease);
}
.footer-list a:hover{color:var(--amber-deep);text-decoration:underline;text-underline-offset:4px;}
.footer-list__row{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:.4rem;
  font-family:var(--font-mono);
  font-size:.75rem;
  line-height:1.6;
}
.footer-list__key{font-family:var(--font-sans);font-size:.74rem;color:var(--muted);}
.footer-list__value{color:var(--ink);word-break:break-all;}
.copy-btn{
  padding:.1rem .48rem;
  border:1px solid var(--line);
  border-radius:999px;
  font-family:var(--font-mono);
  font-size:.66rem;
  color:var(--muted);
  cursor:pointer;
  white-space:nowrap;
  transition:border-color .25s var(--ease),color .25s var(--ease),background .25s var(--ease);
}
.copy-btn:hover{border-color:var(--amber);color:var(--amber-deep);}
.copy-btn[data-copied]{
  border-color:var(--amber);
  background:rgba(232,128,31,.14);
  color:var(--amber-deep);
}

.footer-meta{
  width:min(var(--wrap),calc(100% - var(--gutter) * 2));
  margin-inline:auto;
  display:flex;
  flex-direction:column;
  gap:.4rem;
  padding-block:1.25rem 0;
  border-top:1px solid var(--line);
}
.footer-meta__line{max-width:82ch;font-size:.82rem;color:var(--ink);}
.footer-meta__note{max-width:82ch;font-size:.78rem;color:var(--muted);}
.footer-meta__copy{
  font-family:var(--font-mono);
  font-size:.72rem;
  color:var(--muted);
  letter-spacing:.04em;
}

.ridge{position:relative;height:clamp(64px,9vw,104px);margin-top:1rem;}
.ridge__peak{position:absolute;inset:0;}
.ridge__peak--far{
  background:linear-gradient(180deg,rgba(195,205,212,.28),rgba(195,205,212,.55));
  clip-path:polygon(0 100%,0 62%,8% 44%,15% 58%,26% 28%,36% 54%,46% 36%,58% 62%,68% 40%,78% 60%,88% 44%,100% 64%,100% 100%);
}
.ridge__peak--near{
  background:linear-gradient(180deg,rgba(195,205,212,.45),rgba(195,205,212,.85));
  clip-path:polygon(0 100%,0 84%,10% 66%,20% 82%,31% 58%,42% 78%,54% 64%,66% 84%,76% 66%,88% 80%,100% 70%,100% 100%);
}

/* ---------- 7. 版面骨架 ---------- */
.layout-aside{
  display:grid;
  grid-template-columns:228px minmax(0,1fr);
  gap:clamp(1.5rem,4vw,3.5rem);
  align-items:start;
}
.rail{
  position:sticky;
  top:calc(var(--header-h) + 16px);
  align-self:start;
  display:flex;
  flex-direction:column;
  gap:.9rem;
  padding:1.1rem 1rem;
  background:var(--glass);
  -webkit-backdrop-filter:blur(14px);
  backdrop-filter:blur(14px);
  border:1px solid var(--line);
  border-radius:var(--r-lg);
}
.rail__title{
  font-size:.72rem;
  font-weight:800;
  letter-spacing:.22em;
  color:var(--muted);
}
.rail__list{display:flex;flex-direction:column;gap:.15rem;}
.rail__link{
  display:block;
  padding:.4rem 0;
  font-size:.88rem;
  color:var(--ink);
  text-decoration:none;
  border-bottom:1px solid transparent;
  transition:color .22s var(--ease),border-color .22s var(--ease),padding-left .22s var(--ease);
}
.rail__link:hover{color:var(--amber-deep);padding-left:.25rem;}
.rail__link[aria-current="true"]{
  color:var(--amber-deep);
  font-weight:800;
  border-bottom-color:rgba(232,128,31,.45);
}

.band{padding-block:clamp(2.5rem,6vw,5rem);}
.band--silver{
  background:var(--silver);
  border-top:1px solid var(--line);
  border-bottom:1px solid var(--line);
}
.band--deep{background:var(--deep);color:var(--silver);}
.band--deep h2,.band--deep h3{color:var(--silver);}
.notice-strip{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:.75rem 1.25rem;
  padding:1rem 1.25rem;
  background:var(--deep);
  color:var(--silver);
  border-radius:var(--r-md);
  border-left:3px solid var(--amber);
  font-size:.9rem;
}
.notice-strip .tag{background:rgba(232,128,31,.18);border-color:rgba(232,128,31,.5);color:#F6C08A;}

.page-head{
  display:flex;
  flex-direction:column;
  gap:1rem;
  padding-block:clamp(2.25rem,5vw,4rem) clamp(1.5rem,3vw,2.5rem);
  border-bottom:1px solid var(--line);
}
.page-title{
  font-size:clamp(2.15rem,5.2vw,3.6rem);
  font-weight:900;
  line-height:1.08;
  letter-spacing:-.025em;
  max-width:22ch;
}
.page-lede{max-width:60ch;font-size:1.02rem;color:var(--muted);}

.section-head{
  display:flex;
  flex-wrap:wrap;
  align-items:baseline;
  justify-content:space-between;
  gap:.5rem 1.5rem;
  padding-bottom:.85rem;
  margin-bottom:1.75rem;
  border-bottom:1px solid var(--line);
}
.section-title{font-size:clamp(1.5rem,3vw,2.15rem);font-weight:800;letter-spacing:-.02em;}
.section-lede{font-size:.92rem;color:var(--muted);max-width:52ch;}
.eyebrow{
  display:block;
  font-family:var(--font-mono);
  font-size:.72rem;
  letter-spacing:.24em;
  color:var(--amber-deep);
  margin-bottom:.5rem;
}
.num{
  font-family:var(--font-mono);
  font-size:.78rem;
  color:var(--amber-deep);
  letter-spacing:.06em;
}

.index-list{display:flex;flex-direction:column;gap:.2rem;}
.index-list__item{
  display:flex;
  align-items:baseline;
  gap:.9rem;
  padding:.7rem 0;
  border-bottom:1px solid var(--line);
  font-size:.98rem;
}
.index-list__item .num{flex:none;width:2.6rem;}

/* ---------- 8. 卡片 / 玻璃层 / 标签 ---------- */
.card{
  display:flex;
  flex-direction:column;
  gap:.65rem;
  padding:1.45rem 1.4rem;
  background:var(--silver);
  border:1px solid var(--line);
  border-radius:var(--r-lg);
  box-shadow:var(--shadow);
  transition:border-color .28s var(--ease),transform .28s var(--ease);
}
.card:hover{border-color:var(--amber);transform:translateY(-2px);}
.card__title{font-size:1.28rem;font-weight:800;line-height:1.35;}
.card__meta{
  font-family:var(--font-mono);
  font-size:.72rem;
  letter-spacing:.06em;
  color:var(--muted);
}
.card__text{font-size:.94rem;line-height:1.75;color:var(--ink);}

.glass{
  background:var(--glass);
  -webkit-backdrop-filter:blur(14px) saturate(1.15);
  backdrop-filter:blur(14px) saturate(1.15);
  border:1px solid var(--line);
  border-radius:var(--r-lg);
}
.tag{
  display:inline-block;
  padding:.16rem .5rem;
  border:1px solid rgba(14,143,143,.4);
  border-radius:var(--r-sm);
  background:rgba(14,143,143,.12);
  color:#0A6464;
  font-family:var(--font-mono);
  font-size:.7rem;
  letter-spacing:.04em;
}
.stat{display:flex;flex-direction:column;gap:.15rem;}
.stat__value{font-family:var(--font-mono);font-size:1.5rem;font-weight:700;color:var(--ink);}
.stat__label{font-size:.78rem;color:var(--muted);}

/* ---------- 9. 按钮 / 筛选 / 面包屑 ---------- */
.btn{
  display:inline-flex;
  align-items:center;
  gap:.45rem;
  padding:.68rem 1.15rem;
  border:1px solid transparent;
  border-radius:999px;
  font-size:.94rem;
  font-weight:700;
  text-decoration:none;
  cursor:pointer;
  transition:border-color .25s var(--ease),background .25s var(--ease),color .25s var(--ease),transform .25s var(--ease);
}
.btn:hover{transform:translateY(-1px);}
.btn--primary{background:var(--amber);color:var(--deep);}
.btn--primary:hover{background:#D16F13;}
.btn--ghost{border-color:var(--line);background:rgba(255,255,255,.6);color:var(--ink);}
.btn--ghost:hover{border-color:var(--amber);color:var(--amber-deep);}

.filter-bar{display:flex;flex-wrap:wrap;gap:.5rem;}
.filter-btn{
  padding:.42rem .95rem;
  border:1px solid var(--line);
  border-radius:999px;
  background:rgba(255,255,255,.65);
  font-size:.85rem;
  font-weight:600;
  color:var(--ink);
  cursor:pointer;
  transition:border-color .25s var(--ease),background .25s var(--ease),color .25s var(--ease),transform .25s var(--ease);
}
.filter-btn:hover{border-color:var(--amber);color:var(--amber-deep);}
.filter-btn[aria-pressed="true"]{
  background:var(--amber);
  border-color:var(--amber);
  color:var(--deep);
  font-weight:800;
}
[data-filter-item]{transition:opacity .18s var(--ease),transform .18s var(--ease);}

.breadcrumb{font-family:var(--font-mono);font-size:.74rem;color:var(--muted);}
.breadcrumb__list{display:flex;flex-wrap:wrap;align-items:center;gap:.4rem;}
.breadcrumb__list li{display:flex;align-items:center;gap:.4rem;}
.breadcrumb__list li + li::before{content:"/";color:var(--line);}
.breadcrumb a{color:var(--muted);text-decoration:none;}
.breadcrumb a:hover{color:var(--amber-deep);}

/* ---------- 10. 正文 / 旁注 / 时间带 / 折叠 ---------- */
.prose{max-width:66ch;font-size:17px;line-height:1.85;}
.prose > * + *{margin-top:1.05em;}
.prose h2{font-size:clamp(1.5rem,3vw,2.125rem);margin-top:2.2em;}
.prose h3{font-size:1.28rem;margin-top:1.8em;}
.prose ul,.prose ol{padding-left:1.1rem;list-style:disc;}
.prose ol{list-style:decimal;}
.prose li + li{margin-top:.4rem;}
.prose a{color:var(--amber-deep);text-decoration:underline;text-underline-offset:4px;}
.prose a:hover{color:var(--amber);}
.prose blockquote{
  border-left:3px solid var(--amber);
  padding:.2rem 0 .2rem 1rem;
  color:var(--muted);
}

.note{
  max-width:42ch;
  padding-left:.9rem;
  border-left:2px solid var(--line);
  font-size:.85rem;
  line-height:1.7;
  color:var(--muted);
}
.link-arrow{
  display:inline-flex;
  align-items:center;
  gap:.35rem;
  font-weight:700;
  color:var(--amber-deep);
  text-decoration:none;
}
.link-arrow::after{content:"→";transition:transform .25s var(--ease);}
.link-arrow:hover::after{transform:translateX(3px);}

.timeline{display:flex;flex-direction:column;gap:1.15rem;}
.timeline__item{
  position:relative;
  display:grid;
  grid-template-columns:14px minmax(0,1fr);
  gap:.9rem;
  padding-bottom:1.15rem;
  border-bottom:1px dashed var(--line);
}
.timeline__item:last-child{border-bottom:0;padding-bottom:0;}
.timeline__marker{
  width:12px;height:12px;
  margin-top:.45rem;
  border-radius:50%;
  border:2px solid var(--amber);
  background:transparent;
}
.timeline__item--done .timeline__marker{background:var(--ink);border-color:var(--ink);}

.accordion{display:flex;flex-direction:column;}
.accordion-item{border-bottom:1px solid var(--line);}
.accordion-item__trigger{
  display:flex;
  align-items:baseline;
  gap:.75rem;
  width:100%;
  padding:1.05rem 0;
  text-align:left;
  font-size:1.02rem;
  font-weight:700;
  color:var(--ink);
  cursor:pointer;
  transition:color .22s var(--ease);
}
.accordion-item__trigger::after{
  content:"+";
  margin-left:auto;
  font-family:var(--font-mono);
  font-weight:400;
  color:var(--amber-deep);
  transition:transform .26s var(--ease);
}
.accordion-item__trigger:hover{color:var(--amber-deep);}
.accordion-item[data-open] .accordion-item__trigger::after{transform:rotate(45deg);}
.accordion-item__panel{
  display:none;
  padding:0 0 1.25rem;
  font-size:.95rem;
  line-height:1.8;
  color:var(--ink);
}
.accordion-item[data-open] .accordion-item__panel{display:block;}

/* ---------- 11. 网格与图片容器 ---------- */
.grid{display:grid;gap:1.25rem;}
.grid--cards{grid-template-columns:repeat(auto-fill,minmax(258px,1fr));}
.grid--split{grid-template-columns:minmax(0,7fr) minmax(0,5fr);align-items:start;}
.grid--tight{gap:.75rem;}

.figure{
  position:relative;
  margin:0;
  overflow:hidden;
  border:1px solid var(--line);
  border-radius:var(--r-lg);
  background:linear-gradient(135deg,rgba(248,250,252,.95),rgba(227,234,240,.9));
  aspect-ratio:16 / 10;
}
.figure img,.figure svg{width:100%;height:100%;object-fit:cover;}
.figure--wide{aspect-ratio:21 / 9;}
.figure--tall{aspect-ratio:4 / 5;}
.figure--square{aspect-ratio:1 / 1;}
.figure__caption{
  position:absolute;
  left:.75rem;right:.75rem;bottom:.75rem;
  padding:.5rem .75rem;
  background:var(--glass);
  -webkit-backdrop-filter:blur(10px);
  backdrop-filter:blur(10px);
  border:1px solid var(--line);
  border-radius:var(--r-md);
  font-size:.78rem;
  color:var(--muted);
}

/* ---------- 12. 进场动效 ---------- */
.reveal{transition:opacity .32s var(--ease),transform .32s var(--ease);}
.has-js .reveal:not(.is-in){opacity:0;transform:translateY(14px);}

/* ---------- 13. 响应式 ---------- */
@media (max-width:1080px){
  .index-jump{display:none;}
}
@media (max-width:1000px){
  .layout-aside{grid-template-columns:minmax(0,1fr);}
  .rail{
    position:static;
    flex-direction:row;
    flex-wrap:wrap;
    align-items:center;
    gap:.5rem .9rem;
  }
  .rail__list{flex-direction:row;flex-wrap:wrap;gap:.35rem .9rem;}
  .rail__link{border-bottom:0;padding:.2rem 0;}
  .grid--split{grid-template-columns:minmax(0,1fr);}
}
@media (max-width:900px){
  .nav-toggle{display:inline-flex;}
  .site-nav{
    position:fixed;
    top:0;right:0;
    z-index:55;
    width:min(330px,86vw);
    height:100dvh;
    padding:calc(var(--header-h) + 1.5rem) 1.5rem 2rem;
    background:rgba(248,250,252,.97);
    -webkit-backdrop-filter:blur(18px);
    backdrop-filter:blur(18px);
    border-left:1px solid var(--line);
    box-shadow:-24px 0 46px -34px rgba(20,33,41,.6);
    overflow-y:auto;
    transform:translateX(102%);
    visibility:hidden;
    transition:transform .32s var(--ease),visibility .32s var(--ease);
  }
  .site-nav[data-open]{transform:none;visibility:visible;}
  .site-nav__list{flex-direction:column;align-items:stretch;gap:0;}
  .site-nav__item{width:100%;border-bottom:1px solid var(--line);}
  .site-nav__link{display:block;padding:.95rem 0;font-size:1.05rem;}
  .site-nav__link::after{display:none;}
  .footer-inner{grid-template-columns:repeat(2,minmax(0,1fr));}
}
@media (max-width:640px){
  body{font-size:16px;}
  .brand__line{display:none;}
  .guide-entry{padding:.3rem .6rem;font-size:.76rem;}
  .nav-toggle__text{display:none;}
  .footer-inner{grid-template-columns:minmax(0,1fr);}
  .footer-meta__line,.footer-meta__note{font-size:.76rem;}
  .page-title{max-width:100%;}
}

/* ---------- 14. 无障碍与低动效 ---------- */
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto;}
  *,
  *::before,
  *::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
  }
  .has-js .reveal:not(.is-in){opacity:1;transform:none;}
  .card:hover,.btn:hover,.guide-entry:hover{transform:none;}
  .site-nav{transform:none;}
}