:root{
  --ink:#0E2A3A;
  --ink-2:#1B4560;
  --snow:#F7F5F0;
  --mist:#E7E4DC;
  --maple:#C0432E;
  --fir:#2F5D4E;
  --amber:#E08A3C;
  --meta:#6E7A80;
  --text:#12212A;
  --line:rgba(14,42,58,.12);
  --line-strong:rgba(14,42,58,.24);
  --rail:84px;
  --pad:clamp(20px,4vw,64px);
  --r-lg:28px;
  --r-md:18px;
  --r-sm:12px;
  --font-display:"HarmonyOS Sans SC","PingFang SC","Hiragino Sans GB","Source Han Sans SC","Noto Sans SC","Microsoft YaHei",system-ui,sans-serif;
  --font-body:"PingFang SC","Hiragino Sans GB","Source Han Sans SC","Noto Sans SC","Microsoft YaHei",system-ui,-apple-system,"Segoe UI",sans-serif;
  --font-mono:ui-monospace,"SFMono-Regular","JetBrains Mono","IBM Plex Mono",Menlo,Consolas,monospace;
  --ease:cubic-bezier(.2,.7,.3,1);
}

*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:96px}
body{
  margin:0;
  background-color:var(--snow);
  background-image:repeating-radial-gradient(circle at 84% -6%,rgba(14,42,58,.05) 0 1px,transparent 1px 46px);
  color:var(--text);
  font-family:var(--font-body);
  font-size:16px;
  line-height:1.75;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
img,svg,video{display:block;max-width:100%}
h1,h2,h3,h4,p,figure,blockquote{margin:0}
ul,ol{margin:0;padding:0;list-style:none}
button{font:inherit;color:inherit;background:none;border:0}
a{color:inherit;text-decoration:none}
:focus-visible{outline:2px solid var(--maple);outline-offset:3px;border-radius:6px}
.site-foot :focus-visible,.site-rail :focus-visible{outline-color:var(--amber)}
::selection{background:rgba(192,67,46,.22)}

/* ============ 框架头部 ============ */
.skip-link{
  position:fixed;top:10px;left:10px;z-index:200;
  padding:10px 18px;border-radius:999px;
  background:var(--ink);color:var(--snow);
  font-family:var(--font-mono);font-size:13px;letter-spacing:.06em;
  transform:translateY(-180%);
  transition:transform .18s var(--ease);
}
.skip-link:focus-visible{transform:none}

.site-rail{
  position:fixed;top:0;bottom:0;left:0;z-index:60;
  width:var(--rail);
  display:flex;flex-direction:column;align-items:center;
  gap:10px;
  padding:14px 0 12px;
  background:var(--snow);
  border-right:1px solid var(--line);
}
.rail-progress{
  position:fixed;top:0;left:0;right:0;height:3px;z-index:70;
  background:rgba(14,42,58,.08);
  pointer-events:none;
}
.rail-progress__fill{
  display:block;height:100%;width:0;
  background:linear-gradient(90deg,var(--fir),var(--amber) 55%,var(--maple));
  transition:width .12s linear;
}
.rail-bar{display:flex;flex-direction:column;align-items:center;gap:10px;width:100%}

.rail-brand{display:flex;flex-direction:column;align-items:center;gap:10px;padding:4px 0;border-radius:var(--r-md);width:100%}
.rail-brand__mark{
  width:34px;height:34px;display:grid;place-items:center;
  border-radius:50%;background:var(--maple);color:#fff;
  font-family:var(--font-display);font-weight:800;font-size:15px;line-height:1;
}
.rail-brand__text{display:flex;flex-direction:column;align-items:center;gap:6px}
.rail-brand__name{
  writing-mode:vertical-rl;text-orientation:upright;
  font-family:var(--font-display);font-weight:800;font-size:13px;letter-spacing:.16em;
  color:var(--ink);
}
.rail-brand__tag{
  writing-mode:vertical-rl;text-orientation:upright;
  font-family:var(--font-mono);font-size:9px;letter-spacing:.2em;color:var(--meta);
}
.rail-brand:hover .rail-brand__mark{background:var(--ink)}

.rail-quick{display:none}
.rail-toggle{display:none}

.rail-nav{
  flex:1 1 auto;display:flex;flex-direction:column;justify-content:center;
  width:100%;overflow-y:auto;scrollbar-width:none;
}
.rail-nav::-webkit-scrollbar{display:none}
.rail-nav__list{display:flex;flex-direction:column;align-items:center;gap:2px;width:100%}
.rail-link{
  position:relative;display:flex;flex-direction:column;align-items:center;gap:6px;
  width:100%;padding:8px 4px;border-radius:12px;
  transition:background .18s var(--ease);
}
.rail-link::before{
  content:"";position:absolute;left:7px;top:50%;
  width:2px;height:0;border-radius:2px;background:var(--maple);
  transform:translateY(-50%);
  transition:height .2s var(--ease);
}
.rail-link__num{font-family:var(--font-mono);font-size:10px;letter-spacing:.08em;color:var(--meta)}
.rail-link__label{
  writing-mode:vertical-rl;text-orientation:upright;
  font-family:var(--font-display);font-weight:600;font-size:13px;letter-spacing:.14em;
  color:var(--ink);padding:2px 0;
}
.rail-link:hover{background:var(--mist)}
.rail-link[aria-current="page"]{background:rgba(192,67,46,.08)}
.rail-link[aria-current="page"]::before{height:28px}
.rail-link[aria-current="page"] .rail-link__label,
.rail-link[aria-current="page"] .rail-link__num{color:var(--maple)}

.rail-nav__foot{display:none}

.rail-readout{
  display:flex;flex-direction:column;align-items:center;gap:4px;
  width:100%;padding:10px 0 0;border-top:1px solid var(--line);
}
.rail-readout__index{font-family:var(--font-mono);font-size:12px;letter-spacing:.1em;color:var(--maple)}
.rail-readout__label{
  writing-mode:vertical-rl;text-orientation:upright;
  font-family:var(--font-mono);font-size:9px;letter-spacing:.16em;color:var(--meta);
  max-height:84px;overflow:hidden;
}

/* ============ 通用：容器、章节、文字 ============ */
.shell{width:100%;max-width:1180px;margin-inline:auto;padding-inline:var(--pad)}
.shell--narrow{max-width:840px}
.shell--wide{max-width:1380px}

.section{position:relative;padding-block:clamp(48px,7vw,96px)}
.section--tight{padding-block:clamp(28px,4vw,52px)}
.section--mist{background:var(--mist)}
.section--ink{background:var(--ink);color:var(--snow)}
.section--ink .chapter__title,.section--ink .display{color:var(--snow)}
.section--ink .lead,.section--ink .prose{color:rgba(247,245,240,.84)}
.section--ink .chapter__num{color:var(--amber)}
.section--ink .chapter__note,.section--ink .mono,.section--ink .eyebrow{color:rgba(247,245,240,.55)}

.chapter__head{
  display:flex;align-items:baseline;flex-wrap:wrap;gap:8px 16px;
  margin-bottom:clamp(20px,3vw,36px);
  padding-bottom:14px;border-bottom:1px solid var(--line);
}
.section--ink .chapter__head{border-bottom-color:rgba(247,245,240,.18)}
.chapter__num{font-family:var(--font-mono);font-size:13px;letter-spacing:.16em;color:var(--maple)}
.chapter__title{
  font-family:var(--font-display);font-weight:800;letter-spacing:-.01em;
  font-size:clamp(23px,3vw,34px);line-height:1.28;color:var(--ink);
}
.chapter__note{margin-left:auto;font-family:var(--font-mono);font-size:11px;letter-spacing:.1em;color:var(--meta)}

.display{
  font-family:var(--font-display);font-weight:800;letter-spacing:-.02em;line-height:1.16;
  font-size:clamp(32px,4.6vw,52px);color:var(--ink);
}
.display--sm{font-size:clamp(26px,3.4vw,38px)}
.lead{font-size:clamp(16px,1.5vw,18px);line-height:1.82;color:#2c3f4a;max-width:34em}
.prose{max-width:36em;line-height:1.86;color:#2b3b45}
.prose p+p{margin-top:1em}
.prose strong{font-weight:700;color:var(--ink)}
.mono{font-family:var(--font-mono);font-size:12px;letter-spacing:.08em;color:var(--meta)}
.eyebrow{font-family:var(--font-mono);font-size:11px;letter-spacing:.2em;color:var(--meta);text-transform:uppercase}
.mark{color:var(--maple)}
.rule{height:1px;background:var(--line);border:0;margin:0}
.rule--maple{height:2px;background:linear-gradient(90deg,var(--maple),rgba(192,67,46,0))}
.sr-only{
  position:absolute;width:1px;height:1px;padding:0;margin:-1px;
  overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0;
}

/* ============ 通用：按钮与胶囊 ============ */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:.5em;
  min-height:46px;padding:12px 24px;border-radius:999px;
  border:1px solid transparent;cursor:pointer;
  font-family:var(--font-display);font-weight:700;font-size:15px;letter-spacing:.02em;
  transition:transform .18s var(--ease),background .18s var(--ease),color .18s var(--ease),border-color .18s var(--ease);
}
.btn--maple{background:var(--maple);color:#fff}
.btn--maple:hover{background:#a5361f;transform:translateY(-2px)}
.btn--fir{background:var(--fir);color:var(--snow)}
.btn--fir:hover{background:#264b3f;transform:translateY(-2px)}
.btn--ghost{background:transparent;border-color:var(--line-strong);color:var(--ink)}
.btn--ghost:hover{background:var(--mist)}

.pill{
  display:inline-flex;align-items:center;justify-content:center;gap:6px;
  min-height:36px;padding:6px 14px;border-radius:999px;
  border:1px solid var(--line-strong);background:transparent;color:var(--ink);
  font-family:var(--font-mono);font-size:12px;letter-spacing:.06em;line-height:1.2;
  transition:background .18s var(--ease),color .18s var(--ease),border-color .18s var(--ease),transform .18s var(--ease);
}
.pill--fir{background:var(--fir);border-color:var(--fir);color:var(--snow)}
.pill--fir:hover{background:#264b3f;border-color:#264b3f;transform:translateY(-1px)}
.pill--maple{background:var(--maple);border-color:var(--maple);color:#fff}
.pill--maple:hover{background:#a5361f;border-color:#a5361f}
.pill--ghost:hover{background:var(--mist)}

.tag{
  display:inline-flex;align-items:center;gap:6px;
  padding:5px 12px;border-radius:999px;border:1px solid transparent;
  background:var(--mist);color:var(--ink);
  font-family:var(--font-mono);font-size:12px;letter-spacing:.04em;line-height:1.4;
  transition:background .18s var(--ease),color .18s var(--ease),transform .18s var(--ease);
}
.tag:hover{transform:translateY(-1px)}
.tag--amber{background:rgba(224,138,60,.18);color:#8a4d12}
.tag--on,.tag[aria-pressed="true"]{background:var(--amber);border-color:#c9762c;color:var(--ink)}

/* ============ 通用：面包屑、网格、卡片、图像 ============ */
.crumbs{
  display:flex;flex-wrap:wrap;align-items:center;gap:8px;
  font-family:var(--font-mono);font-size:11px;letter-spacing:.08em;color:var(--meta);
}
.crumbs__sep{opacity:.55}
.crumbs a:hover{color:var(--maple)}
.crumbs [aria-current="page"]{color:var(--ink)}

.grid{display:grid;gap:clamp(16px,2.4vw,32px)}
.grid--12{grid-template-columns:repeat(12,minmax(0,1fr))}
.col-4{grid-column:span 4}
.col-5{grid-column:span 5}
.col-6{grid-column:span 6}
.col-7{grid-column:span 7}
.col-8{grid-column:span 8}
.col-12{grid-column:span 12}
.split{display:grid;grid-template-columns:5fr 7fr;gap:clamp(24px,4vw,56px);align-items:center}
.stack{display:grid;gap:clamp(14px,2vw,24px)}
.stack--tight{gap:10px}

.card{
  background:var(--snow);border:1px solid var(--line);border-radius:var(--r-md);
  padding:clamp(18px,2.2vw,26px);
}
.card--ink{background:var(--ink-2);border-color:rgba(247,245,240,.16);color:var(--snow)}
.card-stack{display:grid;gap:8px}

.media-frame{
  position:relative;overflow:hidden;border-radius:var(--r-lg);
  aspect-ratio:16/10;background-color:var(--mist);
  border:1px solid var(--line);
}
.media-frame img{width:100%;height:100%;object-fit:cover}
.media-frame--wide{aspect-ratio:21/9}
.media-frame--tall{aspect-ratio:4/5}
.media-frame--square{aspect-ratio:1/1}
.media-frame--contour{
  background-image:
    repeating-radial-gradient(circle at 26% 18%,rgba(14,42,58,.12) 0 1px,transparent 1px 22px),
    repeating-linear-gradient(68deg,rgba(14,42,58,.06) 0 1px,transparent 1px 36px);
}
.media-frame--maple{
  background-image:
    repeating-linear-gradient(90deg,rgba(192,67,46,.14) 0 1px,transparent 1px 30px),
    repeating-linear-gradient(0deg,rgba(14,42,58,.08) 0 1px,transparent 1px 30px);
}
.media-frame__caption{
  position:absolute;left:14px;bottom:12px;
  padding:4px 12px;border-radius:999px;
  background:rgba(247,245,240,.88);color:var(--ink);
  font-family:var(--font-mono);font-size:11px;letter-spacing:.08em;
}

/* ============ 滚动显现 ============ */
.js [data-reveal]{opacity:0;transform:translateY(12px);transition:opacity .26s var(--ease),transform .26s var(--ease)}
.js [data-reveal].is-revealed{opacity:1;transform:none}

/* ============ 页脚 ============ */
.site-foot{
  position:relative;overflow:hidden;
  margin-top:clamp(56px,8vw,110px);
  padding:clamp(34px,5vw,64px) var(--pad) 26px;
  background:var(--ink);color:var(--snow);
  border-radius:32px 32px 0 0;
}
.site-foot::before{
  content:"";position:absolute;inset:0;pointer-events:none;
  background-image:
    repeating-linear-gradient(115deg,rgba(247,245,240,.05) 0 1px,transparent 1px 48px),
    repeating-radial-gradient(circle at 12% 0%,rgba(247,245,240,.06) 0 1px,transparent 1px 60px);
}
.foot-top{
  position:relative;
  display:grid;grid-template-columns:minmax(220px,1fr) 2.1fr;
  gap:clamp(28px,4vw,64px);
  padding-bottom:clamp(26px,4vw,44px);
  border-bottom:1px solid rgba(247,245,240,.18);
}
.foot-brand{display:flex;flex-direction:column;align-items:flex-start;gap:10px}
.foot-brand__mark{
  width:40px;height:40px;display:grid;place-items:center;border-radius:50%;
  background:var(--maple);color:#fff;
  font-family:var(--font-display);font-weight:800;font-size:17px;line-height:1;
}
.foot-brand__name{font-family:var(--font-display);font-weight:800;font-size:22px;letter-spacing:.02em}
.foot-brand__line{font-family:var(--font-mono);font-size:11px;letter-spacing:.12em;color:rgba(247,245,240,.58)}
.foot-brand__cta{margin-top:8px}

.foot-cols{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:clamp(20px,3vw,40px)}
.foot-col__title{
  display:flex;align-items:center;gap:8px;
  margin-bottom:14px;
  font-family:var(--font-mono);font-size:11px;font-weight:400;
  letter-spacing:.18em;color:rgba(247,245,240,.6);
}
.foot-col__title::before{content:"";width:14px;height:2px;border-radius:2px;background:var(--maple)}
.foot-list{display:grid;gap:10px}
.foot-link{
  display:inline-block;
  font-size:14px;line-height:1.5;color:rgba(247,245,240,.84);
  overflow-wrap:anywhere;
  transition:color .18s var(--ease),transform .18s var(--ease);
}
.foot-link:hover{color:var(--snow);transform:translateX(2px)}
.foot-legal{
  position:relative;
  display:flex;flex-wrap:wrap;align-items:center;gap:8px 28px;
  padding-top:18px;
}
.foot-legal__item{
  font-family:var(--font-mono);font-size:11px;letter-spacing:.06em;
  color:rgba(247,245,240,.5);
}

.feedback-dock{
  position:fixed;right:20px;bottom:20px;z-index:80;
  display:inline-flex;align-items:center;gap:9px;
  min-height:46px;padding:12px 22px;border-radius:999px;
  background:var(--fir);color:var(--snow);
  font-family:var(--font-display);font-weight:700;font-size:14px;letter-spacing:.04em;
  border:1px solid rgba(247,245,240,.22);
  transition:transform .18s var(--ease),background .18s var(--ease),opacity .2s var(--ease),visibility .2s var(--ease);
}
.feedback-dock:hover{background:#264b3f;transform:translateY(-2px)}
.feedback-dock__dot{
  width:8px;height:8px;border-radius:50%;background:var(--amber);
  box-shadow:0 0 0 0 rgba(224,138,60,.7);
  animation:dock-pulse 2.6s ease-out infinite;
}
@keyframes dock-pulse{
  0%{box-shadow:0 0 0 0 rgba(224,138,60,.6)}
  70%{box-shadow:0 0 0 9px rgba(224,138,60,0)}
  100%{box-shadow:0 0 0 0 rgba(224,138,60,0)}
}

/* ============ 响应式：平板与手机 ============ */
@media (min-width:1025px){
  body{padding-left:var(--rail)}
  .rail-progress{left:var(--rail)}
  .rail-progress__fill{background:linear-gradient(90deg,var(--fir),var(--maple))}
}

@media (max-width:1024px){
  html{scroll-padding-top:84px}
  body{padding-top:62px}
  .site-rail{
    top:0;right:0;bottom:auto;left:0;width:auto;
    align-items:stretch;gap:0;padding:0;
    background:var(--ink);color:var(--snow);
    border-right:0;border-bottom:1px solid rgba(247,245,240,.18);
  }
  .rail-bar{
    flex-direction:row;align-items:center;gap:12px;
    min-height:61px;padding:10px 16px;width:100%;
  }
  .rail-brand{flex-direction:row;align-items:center;gap:10px;width:auto;padding:0}
  .rail-brand__mark{width:30px;height:30px;font-size:13px}
  .rail-brand__mark:hover{background:var(--maple)}
  .rail-brand__text{align-items:flex-start;gap:0}
  .rail-brand__name{writing-mode:horizontal-tb;text-orientation:mixed;font-size:15px;letter-spacing:.08em;color:var(--snow)}
  .rail-brand__tag{writing-mode:horizontal-tb;text-orientation:mixed;font-size:9px;letter-spacing:.14em;color:rgba(247,245,240,.55)}
  .rail-quick{display:flex;align-items:center;gap:8px;margin-left:auto}
  .rail-quick .pill{min-height:34px;padding:6px 12px;font-size:11px}
  .rail-quick .pill--ghost{border-color:rgba(247,245,240,.36);color:var(--snow)}
  .rail-quick .pill--ghost:hover{background:rgba(247,245,240,.14)}
  .rail-toggle{
    display:inline-flex;align-items:center;gap:8px;
    min-width:44px;min-height:44px;padding:0 14px;
    border:1px solid rgba(247,245,240,.32);border-radius:999px;
    background:transparent;color:var(--snow);cursor:pointer;
    transition:background .18s var(--ease),color .18s var(--ease),border-color .18s var(--ease);
  }
  .rail-toggle__lines{display:grid;gap:3px;width:16px}
  .rail-toggle__lines i{display:block;height:2px;border-radius:2px;background:currentColor;transition:transform .2s var(--ease),opacity .2s var(--ease)}
  .rail-toggle__label{font-family:var(--font-mono);font-size:11px;letter-spacing:.12em}
  .site-rail[data-open] .rail-toggle{background:var(--snow);color:var(--ink);border-color:var(--snow)}
  .site-rail[data-open] .rail-toggle__lines i:nth-child(1){transform:translateY(5px) rotate(45deg)}
  .site-rail[data-open] .rail-toggle__lines i:nth-child(2){opacity:0}
  .site-rail[data-open] .rail-toggle__lines i:nth-child(3){transform:translateY(-5px) rotate(-45deg)}

  .rail-nav{
    display:none;flex-direction:column;justify-content:flex-start;
    width:100%;padding:16px 16px 18px;
    background:var(--ink-2);border-top:1px solid rgba(247,245,240,.16);
    overflow:visible;
  }
  .site-rail[data-open] .rail-nav{display:flex}
  .rail-nav__list{display:flex;flex-wrap:wrap;align-items:stretch;gap:8px;width:100%}
  .rail-link{
    flex-direction:row;align-items:center;gap:8px;width:auto;
    min-height:44px;padding:10px 15px;
    border:1px solid rgba(247,245,240,.24);border-radius:999px;
    background:transparent;
  }
  .rail-link::before{display:none}
  .rail-link__num{font-size:10px;color:rgba(247,245,240,.62)}
  .rail-link__label{
    writing-mode:horizontal-tb;text-orientation:mixed;
    font-size:14px;letter-spacing:.04em;color:var(--snow);padding:0;
  }
  .rail-link:hover{background:rgba(247,245,240,.14)}
  .rail-link[aria-current="page"]{background:var(--snow);border-color:var(--snow)}
  .rail-link[aria-current="page"] .rail-link__label{color:var(--ink)}
  .rail-link[aria-current="page"] .rail-link__num{color:var(--maple)}

  .rail-nav__foot{
    display:flex;align-items:center;justify-content:space-between;
    flex-wrap:wrap;gap:12px;margin-top:16px;
    padding-top:14px;border-top:1px solid rgba(247,245,240,.16);
  }
  .rail-nav__note{font-family:var(--font-mono);font-size:10px;letter-spacing:.1em;color:rgba(247,245,240,.5)}
  .rail-nav__cta{min-height:44px;padding-inline:20px}
  .rail-readout{display:none}

  .feedback-dock{
    opacity:0;visibility:hidden;transform:translateY(10px);
    right:16px;bottom:16px;min-height:44px;padding:11px 18px;font-size:13px;
  }
  .feedback-dock[data-visible="true"]{opacity:1;visibility:visible;transform:none}

  .foot-top{grid-template-columns:1fr}
  .foot-cols{grid-template-columns:repeat(3,minmax(0,1fr))}
}

@media (min-width:641px) and (max-width:1024px){
  .site-rail[data-open] .rail-nav__list{flex-wrap:nowrap;overflow-x:auto;padding-bottom:6px;scrollbar-width:none}
  .site-rail[data-open] .rail-nav__list::-webkit-scrollbar{display:none}
  .rail-link{flex:0 0 auto}
}

@media (max-width:900px){
  .split{grid-template-columns:1fr}
  .grid--12{grid-template-columns:repeat(6,minmax(0,1fr))}
  .col-4,.col-5,.col-6,.col-7,.col-8,.col-12{grid-column:span 6}
}

@media (max-width:640px){
  body{font-size:16px}
  .rail-quick{display:none}
  .rail-toggle{padding:0 12px}
  .rail-nav__list{flex-direction:column;flex-wrap:nowrap;align-items:stretch}
  .rail-link{width:100%;justify-content:flex-start}
  .rail-nav__foot{flex-direction:column;align-items:flex-start}
  .rail-nav__cta{width:100%}
  .foot-cols{grid-template-columns:1fr;gap:24px}
  .site-foot{border-radius:24px 24px 0 0}
  .foot-brand__name{font-size:20px}
  .feedback-dock{right:12px;bottom:12px}
  .chapter__note{margin-left:0;width:100%}
}

@media (min-width:1025px){
  .rail-nav__foot{display:none}
}

@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
    scroll-behavior:auto !important;
  }
  .js [data-reveal]{opacity:1;transform:none}
}