/* ================= 1. reset ================= */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{margin:0}
img,svg,picture{display:block;max-width:100%}
button,input,select,textarea{font:inherit;color:inherit}
ul,ol{margin:0;padding:0;list-style:none}
a{color:inherit}
h1,h2,h3,h4,h5,h6,p,figure,blockquote{margin:0}
::selection{background:var(--cinnabar-500);color:var(--paper-50)}

/* ================= 2. tokens ================= */
:root{
  --ink-950:#0A1A2A;
  --ink-850:#10283D;
  --ink-800:#16324A;
  --ink-700:#1D3E58;
  --amber-450:#E1A63B;
  --amber-200:#F3D69A;
  --cinnabar-500:#C84A35;
  --celadon-400:#7FA99B;
  --smoke-100:#EDE7DC;
  --smoke-400:#B7B0A3;
  --paper-50:#F7F3EA;
  --line-500:#2A4258;
  --rail-w:240px;
  --bar-h:64px;
  --gap:clamp(16px,2vw,28px);
  --measure:68ch;
  --dur:220ms;
  --ease:cubic-bezier(.22,.7,.28,1);
  --serif:"Noto Serif SC","Source Han Serif SC","Songti SC","SimSun",serif;
  --sans:"Noto Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  --mono:"JetBrains Mono","IBM Plex Mono",ui-monospace,SFMono-Regular,Menlo,monospace;
}

/* ================= 3. base / 中文排版 ================= */
body{
  background-color:var(--ink-950);
  background-image:
    radial-gradient(120% 78% at 100% 0%,rgba(225,166,59,.10),transparent 58%),
    radial-gradient(90% 70% at 0% 100%,rgba(127,169,155,.09),transparent 62%);
  background-attachment:fixed;
  color:var(--smoke-100);
  font-family:var(--sans);
  font-size:16px;
  line-height:28px;
  font-weight:400;
  letter-spacing:.01em;
  -webkit-font-smoothing:antialiased;
}
h1,h2,h3,h4{
  font-family:var(--serif);
  font-weight:600;
  letter-spacing:.02em;
  color:var(--smoke-100);
  text-wrap:balance;
}
h1{font-size:clamp(36px,5vw,56px);line-height:1.2}
h2{font-size:clamp(26px,3vw,34px);line-height:1.32}
h3{font-size:20px;line-height:1.5}
h4{font-size:17px;line-height:1.55}
p{margin:0 0 1em}
p:last-child{margin-bottom:0}
:focus-visible{outline:2px solid var(--amber-200);outline-offset:3px;border-radius:2px}
.visually-hidden{position:absolute;width:1px;height:1px;margin:-1px;padding:0;overflow:hidden;clip:rect(0 0 0 0);clip-path:inset(50%);white-space:nowrap;border:0}

/* ================= 4. skip link ================= */
.skip-link{
  position:fixed;top:10px;left:10px;z-index:200;
  transform:translateY(-200%);
  background:var(--amber-450);color:var(--ink-950);
  padding:10px 16px;border-radius:2px;
  font:600 13px/1 var(--sans);letter-spacing:.04em;text-decoration:none;
  transition:transform var(--dur) var(--ease);
}
.skip-link:focus,.skip-link:focus-visible{transform:none}

/* ================= 5. header / 书脊 ================= */
.site-header{
  position:sticky;top:0;z-index:70;
  background:linear-gradient(180deg,rgba(16,40,61,.99),rgba(10,26,42,.99));
  border-bottom:1px solid var(--line-500);
  box-shadow:0 12px 26px -22px #000;
}
.site-header__bar{
  display:flex;align-items:center;gap:10px;
  min-height:var(--bar-h);
  padding:10px clamp(14px,4vw,20px);
}
.brand-plate{
  display:flex;align-items:center;gap:10px;
  margin-inline-end:auto;
  text-decoration:none;color:inherit;
}
.brand-mark{
  display:grid;place-items:center;
  width:34px;height:34px;
  border:1px solid var(--amber-450);
  background:rgba(225,166,59,.08);
  color:var(--amber-450);
  font-family:var(--serif);font-size:19px;line-height:1;
  transition:background var(--dur) var(--ease);
}
.brand-plate:hover .brand-mark{background:rgba(225,166,59,.2)}
.brand-text{display:flex;flex-direction:column;line-height:1.2}
.brand-name{font-family:var(--serif);font-weight:600;font-size:17px;letter-spacing:.07em;color:var(--smoke-100)}
.brand-sub{font-family:var(--mono);font-size:9.5px;letter-spacing:.2em;color:var(--smoke-400);margin-top:2px}

.version-chip{
  display:inline-flex;align-items:center;gap:6px;
  padding:5px 9px;
  border:1px solid var(--line-500);border-radius:999px;
  background:rgba(10,26,42,.65);
  text-decoration:none;
  font-family:var(--mono);font-size:10.5px;letter-spacing:.12em;
  color:var(--amber-200);
  transition:border-color var(--dur) var(--ease),background var(--dur) var(--ease);
}
.version-chip:hover{border-color:var(--amber-450);background:rgba(225,166,59,.1)}
.version-chip__dot{width:6px;height:6px;border-radius:50%;background:var(--celadon-400);box-shadow:0 0 0 3px rgba(127,169,155,.18)}
.version-chip__label{color:var(--amber-450)}
.version-chip__hint{display:none;color:var(--smoke-400);letter-spacing:.14em}

.nav-toggle{
  display:inline-flex;align-items:center;gap:8px;
  padding:9px 12px;
  background:transparent;
  border:1px solid var(--line-500);border-radius:2px;
  color:var(--smoke-100);
  font:500 12px/1 var(--mono);letter-spacing:.16em;
  cursor:pointer;
  transition:border-color var(--dur) var(--ease),color var(--dur) var(--ease);
}
.nav-toggle:hover{border-color:var(--amber-450);color:var(--amber-200)}
.nav-toggle__bars{position:relative;display:block;width:16px;height:10px}
.nav-toggle__bars::before,.nav-toggle__bars::after{
  content:"";position:absolute;left:0;width:16px;height:1px;background:var(--amber-450);
  transition:transform var(--dur) var(--ease);
}
.nav-toggle__bars::before{top:1px}
.nav-toggle__bars::after{top:7px}
.site-header[data-open="true"] .nav-toggle__bars::before{transform:translateY(3px) rotate(45deg)}
.site-header[data-open="true"] .nav-toggle__bars::after{transform:translateY(-3px) rotate(-45deg)}

.site-nav{
  display:none;
  border-top:1px solid var(--line-500);
  padding:16px clamp(14px,4vw,20px) 20px;
  max-height:calc(100vh - var(--bar-h) - 12px);
  overflow-y:auto;
  background:linear-gradient(180deg,rgba(16,40,61,.9),rgba(10,26,42,.98));
}
.site-header[data-open="true"] .site-nav{display:block}
.rail-caption{
  margin:0 0 10px;
  font-family:var(--mono);font-size:10px;letter-spacing:.24em;text-transform:uppercase;
  color:var(--smoke-400);
}
.nav-list{display:grid;gap:2px}
.nav-link{
  display:flex;align-items:baseline;gap:10px;
  padding:10px 10px;
  text-decoration:none;
  color:var(--smoke-100);
  border-inline-start:2px solid transparent;
  transition:background var(--dur) var(--ease),color var(--dur) var(--ease),border-color var(--dur) var(--ease);
}
.nav-index{font-family:var(--mono);font-size:11px;letter-spacing:.1em;color:var(--celadon-400);min-width:2.2ch}
.nav-label{font-size:15px;letter-spacing:.03em}
.nav-link:hover{background:rgba(225,166,59,.09);color:var(--amber-200);border-inline-start-color:var(--amber-450)}
.nav-link:hover .nav-index{color:var(--amber-200)}
.nav-link[aria-current="page"]{
  background:linear-gradient(90deg,rgba(225,166,59,.18),rgba(225,166,59,0));
  border-inline-start-color:var(--cinnabar-500);
  color:var(--amber-200);
}
.nav-link[aria-current="page"] .nav-index{color:var(--cinnabar-500)}
.nav-link[aria-current="page"] .nav-label::after{
  content:"当前";
  font-family:var(--mono);font-size:9px;letter-spacing:.16em;
  color:var(--cinnabar-500);
  margin-inline-start:8px;vertical-align:2px;
}
.rail-foot{
  margin-top:18px;padding-top:14px;
  border-top:1px dashed var(--line-500);
  display:grid;gap:6px;
}
.rail-foot__line{
  display:flex;justify-content:space-between;gap:10px;
  font-family:var(--mono);font-size:11px;letter-spacing:.09em;
  color:var(--smoke-400);
}
.rail-foot__val{color:var(--amber-200)}
.rail-foot__note{margin:4px 0 0;font-size:12px;line-height:1.65;color:var(--smoke-400)}
.rail-cta{
  display:inline-flex;align-items:center;gap:8px;
  margin-top:6px;padding:9px 12px;
  align-self:start;
  border:1px solid var(--cinnabar-500);
  background:rgba(200,74,53,.14);
  color:var(--paper-50);
  text-decoration:none;
  font-size:13px;letter-spacing:.04em;
  transition:background var(--dur) var(--ease),color var(--dur) var(--ease);
}
.rail-cta::after{content:"→";font-family:var(--mono);font-size:12px;color:var(--amber-200)}
.rail-cta:hover{background:var(--cinnabar-500);color:#fff}
.rail-cta:hover::after{color:#fff}

.rail-progress{position:absolute;left:0;right:0;bottom:-1px;height:2px;pointer-events:none}
.rail-progress__fill{
  display:block;width:100%;height:100%;
  background:linear-gradient(90deg,var(--celadon-400),var(--amber-450));
  transform-origin:left center;
  transform:scaleX(var(--progress,0));
}

/* ================= 6. footer ================= */
.site-footer{
  background:linear-gradient(180deg,var(--ink-850),#0C2135);
  border-top:1px solid var(--line-500);
  color:var(--smoke-100);
}
.footer-top{
  display:grid;gap:var(--gap);
  padding:clamp(28px,5vw,56px) clamp(16px,4vw,48px);
  grid-template-columns:1fr;
  max-width:1240px;
}
.footer-brand{display:grid;gap:10px;align-content:start}
.footer-mark{
  display:grid;place-items:center;width:38px;height:38px;
  border:1px solid var(--amber-450);
  background:rgba(225,166,59,.09);
  color:var(--amber-450);
  font-family:var(--serif);font-size:20px;line-height:1;
}
.footer-name{font-family:var(--serif);font-size:17px;font-weight:600;letter-spacing:.05em;margin:0}
.footer-desc{font-size:13.5px;line-height:24px;color:var(--smoke-400);max-width:34ch;margin:0}
.footer-title{
  font-family:var(--mono);font-size:10px;letter-spacing:.24em;text-transform:uppercase;
  color:var(--celadon-400);
  margin:0 0 12px;
  padding-bottom:8px;
  border-bottom:1px solid var(--line-500);
}
.footer-list{display:grid;gap:8px}
.footer-link{
  font-size:14px;letter-spacing:.03em;
  color:var(--smoke-100);text-decoration:none;
  border-bottom:1px solid transparent;
  transition:color var(--dur) var(--ease),border-color var(--dur) var(--ease);
}
.footer-link:hover{color:var(--amber-200);border-bottom-color:var(--amber-450)}
.footer-link[aria-current="page"]{color:var(--amber-200)}
.footer-facts{display:grid;gap:10px}
.footer-facts li{display:grid;gap:2px}
.footer-key{
  font-family:var(--mono);font-size:10px;letter-spacing:.2em;text-transform:uppercase;
  color:var(--smoke-400);
}
.footer-val{font-size:13.5px;line-height:22px;color:var(--smoke-100);word-break:break-word}
.footer-rule{display:grid;gap:12px;align-content:start}
.footer-cta{
  display:inline-flex;align-items:center;gap:8px;
  padding:11px 16px;
  align-self:start;
  border:1px solid var(--cinnabar-500);
  background:rgba(200,74,53,.15);
  color:var(--paper-50);
  text-decoration:none;
  font-size:14px;letter-spacing:.04em;
  border-radius:2px;
  transition:background var(--dur) var(--ease),color var(--dur) var(--ease);
}
.footer-cta::after{content:"→";font-family:var(--mono);font-size:12px;color:var(--amber-200)}
.footer-cta:hover{background:var(--cinnabar-500);color:#fff}
.footer-cta:hover::after{color:#fff}
.footer-hint{font-size:12px;line-height:20px;color:var(--smoke-400);margin:0}
.footer-base{
  display:flex;flex-wrap:wrap;gap:8px 24px;
  padding:14px clamp(16px,4vw,48px) 20px;
  border-top:1px solid var(--line-500);
  max-width:1240px;
}
.footer-fine{
  margin:0;
  font-family:var(--mono);font-size:11px;line-height:18px;letter-spacing:.08em;
  color:var(--smoke-400);
}
.footer-year{color:var(--amber-200)}

/* ================= 7. layout containers ================= */
.container{
  width:100%;max-width:1180px;
  margin-inline:auto;
  padding-inline:clamp(16px,4vw,48px);
}
.site-main{display:block;min-height:56vh}
.section{
  padding-block:clamp(28px,4.5vw,60px);
  border-top:1px solid var(--line-500);
}
.section:first-child{border-top:0}
.stack{display:grid;gap:var(--gap)}
.stack--tight{display:grid;gap:12px}
.grid{display:grid;gap:var(--gap);grid-template-columns:1fr}

/* ================= 8. 文字组件 ================= */
.kicker{
  display:inline-flex;align-items:center;gap:8px;
  margin:0 0 12px;
  font-family:var(--mono);font-size:10.5px;letter-spacing:.24em;text-transform:uppercase;
  color:var(--celadon-400);
}
.kicker::before{content:"";width:22px;height:1px;background:var(--amber-450)}
.lede{font-size:clamp(16px,1.6vw,18px);line-height:1.78;color:var(--smoke-400);max-width:58ch;margin:0}
.prose{max-width:var(--measure);font-size:16px;line-height:28px;color:var(--smoke-100)}
.prose p{margin:0 0 1em}
.prose ul,.prose ol{margin:0 0 1em;padding-inline-start:1.3em;list-style:disc}
.prose ol{list-style:decimal}
.prose li{margin-bottom:.4em}
.prose a{color:var(--amber-450);text-underline-offset:3px}
.prose h3{margin:1.4em 0 .5em}
.mono{font-family:var(--mono);letter-spacing:.08em;font-size:.9em;color:var(--celadon-400)}
.num{font-family:var(--mono);color:var(--amber-450);letter-spacing:.06em}
.annot{
  text-decoration:underline;
  text-decoration-color:var(--amber-450);
  text-decoration-thickness:2px;
  text-underline-offset:4px;
  text-decoration-skip-ink:none;
}
.rule{border:0;height:1px;background:var(--line-500);margin:0}

/* ================= 9. 按钮 ================= */
.btn{
  display:inline-flex;align-items:center;gap:10px;
  padding:12px 20px;
  border:1px solid var(--amber-450);
  background:var(--amber-450);
  color:var(--ink-950);
  font:500 14px/1 var(--sans);letter-spacing:.06em;
  text-decoration:none;border-radius:2px;
  transition:background var(--dur) var(--ease),border-color var(--dur) var(--ease),color var(--dur) var(--ease);
}
.btn:hover{background:var(--amber-200);border-color:var(--amber-200)}
.btn--line{background:transparent;border-color:var(--line-500);color:var(--amber-200)}
.btn--line:hover{border-color:var(--amber-450);color:var(--amber-450);background:rgba(225,166,59,.09)}
.btn--ghost{
  background:transparent;border-color:transparent;color:var(--smoke-100);
  padding:12px 4px;text-decoration:underline;text-underline-offset:5px;
  text-decoration-color:var(--line-500);
}
.btn--ghost:hover{color:var(--amber-200);text-decoration-color:var(--amber-450)}

/* ================= 10. 面包屑 ================= */
.breadcrumb{margin-block:0 18px}
.breadcrumb__list{
  display:flex;flex-wrap:wrap;gap:6px;
  font-family:var(--mono);font-size:11px;letter-spacing:.12em;
  color:var(--smoke-400);
}
.breadcrumb__list li{display:inline-flex;align-items:center;gap:6px}
.breadcrumb__list li+li::before{content:"/";color:var(--line-500)}
.crumb{color:var(--smoke-400);text-decoration:none}
.crumb:hover{color:var(--amber-450)}
.crumb[aria-current="page"]{color:var(--amber-200)}

/* ================= 11. 标签 / 卡片 ================= */
.badge{
  display:inline-flex;align-items:center;gap:6px;
  padding:3px 9px;
  border:1px solid var(--line-500);border-radius:999px;
  font-family:var(--mono);font-size:10px;letter-spacing:.14em;text-transform:uppercase;
  color:var(--smoke-400);
}
.badge--amber{color:var(--amber-200);border-color:rgba(225,166,59,.5);background:rgba(225,166,59,.1)}
.badge--celadon{color:#A8C9BD;border-color:rgba(127,169,155,.5);background:rgba(127,169,155,.1)}
.badge--red{color:#E5A094;border-color:rgba(200,74,53,.55);background:rgba(200,74,53,.14)}

.card{
  position:relative;
  display:block;
  background:var(--ink-850);
  border:1px solid var(--line-500);
  border-radius:2px;
  padding:20px;
  box-shadow:0 1px 0 rgba(255,255,255,.03),0 18px 30px -28px #000;
  transition:border-color var(--dur) var(--ease),background var(--dur) var(--ease);
}
.card:hover{border-color:#3A5A76;background:#122C43}
.card__head{
  display:flex;align-items:baseline;justify-content:space-between;gap:12px;
  margin-bottom:10px;
}
.card__num{font-family:var(--mono);font-size:12px;letter-spacing:.14em;color:var(--celadon-400)}
.card__title{font-family:var(--serif);font-size:18px;font-weight:600;line-height:1.5;margin:0 0 8px;color:var(--smoke-100)}
.card__text{font-size:14px;line-height:24px;color:var(--smoke-400);margin:0}

/* ================= 12. 图片容器 ================= */
.figure-frame{
  position:relative;
  margin:0;
  aspect-ratio:16/10;
  border:1px solid var(--line-500);
  background:linear-gradient(160deg,var(--ink-800),var(--ink-850));
  overflow:hidden;
  border-radius:2px;
}
.figure-frame img{width:100%;height:100%;object-fit:cover}
.figure-frame::after{
  content:"";position:absolute;inset:8px;
  border:1px dashed rgba(243,214,154,.16);
  pointer-events:none;
}
.figure-frame--wide{aspect-ratio:16/9}
.figure-frame--tall{aspect-ratio:3/4}
.figure-frame--phone{aspect-ratio:9/19;max-width:280px}
.figure-caption{
  margin-top:9px;
  font-family:var(--mono);font-size:11px;line-height:18px;letter-spacing:.1em;
  color:var(--smoke-400);
}

/* ================= 13. 分段标签 ================= */
.tab-list{
  display:flex;flex-wrap:wrap;gap:4px;
  border-bottom:1px solid var(--line-500);
  margin:0 0 18px;
}
.tab-btn{
  appearance:none;background:transparent;border:0;
  border-bottom:2px solid transparent;
  padding:10px 14px;
  display:inline-flex;align-items:center;gap:8px;
  color:var(--smoke-400);
  font:500 14px/1.4 var(--sans);letter-spacing:.04em;
  cursor:pointer;
  transition:color var(--dur) var(--ease),background var(--dur) var(--ease),border-color var(--dur) var(--ease);
}
.tab-btn:hover{color:var(--amber-200);background:rgba(225,166,59,.08)}
.tab-btn[aria-selected="true"]{color:var(--amber-200);border-bottom-color:var(--cinnabar-500)}
.tab-btn__idx{font-family:var(--mono);font-size:11px;color:var(--celadon-400)}
.tab-panel{animation:panelIn var(--dur) var(--ease) both}
.tab-panel[hidden]{display:none}
@keyframes panelIn{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:none}}

/* ================= 14. 显现 ================= */
[data-reveal]{transition:opacity 520ms var(--ease),transform 520ms var(--ease)}
[data-reveal].is-armed{opacity:0;transform:translateY(14px)}
[data-reveal].is-in{opacity:1;transform:none}

/* ================= 15. 响应式 ================= */
@media (min-width:600px){
  .grid--2{grid-template-columns:repeat(2,minmax(0,1fr))}
  .footer-top{grid-template-columns:repeat(2,minmax(0,1fr));gap:28px 32px}
  .footer-brand{grid-column:1 / -1}
}
@media (min-width:768px){
  .footer-base{gap:10px 28px}
  .nav-toggle__text{font-size:12px}
}
@media (min-width:900px){
  .grid--3{grid-template-columns:repeat(3,minmax(0,1fr))}
}
@media (min-width:1024px){
  .skip-link{left:calc(var(--rail-w) + 14px)}
  .site-header{
    position:fixed;inset-block:0;inset-inline-start:0;
    width:var(--rail-w);height:100%;
    display:flex;flex-direction:column;
    border-bottom:0;border-inline-end:1px solid var(--line-500);
    background:linear-gradient(168deg,#10283D 0%,#0A1A2A 68%);
    box-shadow:1px 0 0 rgba(0,0,0,.55),18px 0 40px -40px #000;
  }
  .site-header__bar{
    flex-direction:column;align-items:stretch;gap:14px;
    min-height:0;
    padding:24px 20px 18px;
  }
  .brand-plate{margin-inline-end:0}
  .brand-name{font-size:18px}
  .version-chip{align-self:flex-start}
  .version-chip__hint{display:inline}
  .nav-toggle{display:none}
  .site-nav{
    display:block;
    flex:1 1 auto;
    min-height:0;
    overflow-y:auto;
    border-top:1px solid var(--line-500);
    padding:18px 12px 22px;
    background:transparent;
    max-height:none;
  }
  .rail-caption{padding-inline-start:10px}
  .nav-link{padding:9px 10px}
  .rail-progress{
    left:auto;right:0;top:0;bottom:0;
    width:2px;height:auto;
  }
  .rail-progress__fill{
    width:100%;height:100%;
    transform-origin:center top;
    transform:scaleY(var(--progress,0));
  }
  .site-main{margin-inline-start:var(--rail-w)}
  .site-footer{margin-inline-start:var(--rail-w)}
  .footer-top{
    grid-template-columns:1.5fr .8fr 1.15fr 1fr;
    align-items:start;
    padding-inline:clamp(24px,4vw,56px);
  }
  .footer-brand{grid-column:auto}
  .footer-base{padding-inline:clamp(24px,4vw,56px)}
}
@media (min-width:1280px){
  .footer-top{gap:36px 44px}
}

/* ================= 16. 减弱动效 ================= */
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
  }
  [data-reveal].is-armed{opacity:1;transform:none}
  .skip-link{transition:none}
}