/* =============================================================
   开元指南 · 共享样式 /assets/site.css
   01 tokens  02 reset  03 base  04 layout  05 typography
   06 buttons  07 breadcrumb  08 components  09 header
   10 footer  11 responsive  12 motion
   ============================================================= */

/* 01 · tokens -------------------------------------------------- */
:root{
  --copper:#2F6B5A;
  --copper-deep:#17483B;
  --copper-ink:#123529;
  --gold:#C9A227;
  --gold-bright:#E4C86A;
  --gold-deep:#8A6A12;
  --cinnabar:#C4401F;
  --cinnabar-deep:#A63417;
  --paper:#F7F2E7;
  --paper-2:#EFE7D6;
  --ink:#1B1A17;
  --ink-soft:#3A382F;
  --stone:#6B665C;
  --mint:#D9E7DF;
  --patina:#7A5C3E;
  --line:rgba(27,26,23,.14);
  --line-gold:rgba(201,162,39,.45);
  --hair-dim:rgba(247,242,231,.16);
  --font-serif:"Songti SC","Source Han Serif SC","Noto Serif SC","SimSun",Georgia,"Times New Roman",serif;
  --font-sans:"PingFang SC","Hiragino Sans GB","Microsoft YaHei","Noto Sans SC",system-ui,-apple-system,"Segoe UI",sans-serif;
  --font-mono:"IBM Plex Mono","JetBrains Mono","SFMono-Regular",Menlo,Consolas,"Courier New",monospace;
  --shell:1280px;
  --gutter:clamp(1.1rem,4vw,3rem);
  --radius-organic:22px 6px 22px 6px;
  --radius-soft:6px;
  --shadow-lift:0 20px 44px -32px rgba(23,72,59,.6);
  --ease:cubic-bezier(.22,.61,.36,1);
  --header-h:66px;
}

/* 02 · reset --------------------------------------------------- */
*,*::before,*::after{box-sizing:border-box}
*{margin:0}
html{-webkit-text-size-adjust:100%;text-size-adjust:100%;scroll-behavior:smooth}
body{min-height:100%}
img,svg,picture,video{display:block;max-width:100%}
img{height:auto}
button,input,select,textarea{font:inherit;color:inherit}
button{background:none;border:0;padding:0}
a{color:inherit;text-decoration:none}
ul,ol{list-style:none;padding:0}
table{border-collapse:collapse;width:100%}
:where(h1,h2,h3,h4,h5){font-weight:600;line-height:1.28;letter-spacing:.01em}

/* 03 · base ---------------------------------------------------- */
body{
  background-color:var(--paper);
  color:var(--ink);
  font-family:var(--font-sans);
  font-size:17px;
  line-height:1.75;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
h1,h2,h3{font-family:var(--font-serif);color:var(--ink)}
h1{font-size:clamp(2.25rem,5vw,4.25rem);line-height:1.16}
h2{font-size:clamp(1.7rem,3.4vw,2.45rem)}
h3{font-size:clamp(1.15rem,1.8vw,1.5rem)}
p{color:var(--ink-soft)}
strong{font-weight:600;color:var(--ink)}
::selection{background:rgba(201,162,39,.4);color:var(--ink)}
:focus-visible{outline:2px solid var(--gold-deep);outline-offset:3px;border-radius:2px}
.site-header :focus-visible,.site-footer :focus-visible{outline-color:var(--gold)}
main{display:block}
#main-content:focus{outline:none}

.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;
}
.skip-link{
  position:absolute;left:.75rem;top:-4.5rem;z-index:200;
  display:inline-block;padding:.62rem 1.05rem;
  background:var(--paper);color:var(--ink);
  border:1px solid var(--gold);border-radius:2px;
  font-size:.86rem;letter-spacing:.04em;
  transition:top .2s var(--ease);
}
.skip-link:focus{top:.55rem}

/* 04 · layout -------------------------------------------------- */
.shell{
  width:min(calc(100% - 2 * var(--gutter)),var(--shell));
  margin-inline:auto;
}
.section{padding-block:clamp(2.6rem,6vw,5.5rem)}
.stack > * + *{margin-top:var(--stack-gap,1.1rem)}
.grid-12{
  display:grid;
  grid-template-columns:repeat(12,minmax(0,1fr));
  gap:clamp(1rem,2.4vw,2rem);
}
.split-editorial{
  display:grid;
  grid-template-columns:minmax(0,7fr) minmax(0,5fr);
  gap:clamp(1.4rem,4vw,3.4rem);
  align-items:start;
}
.split-editorial--flip{grid-template-columns:minmax(0,5fr) minmax(0,7fr)}

/* 05 · typography --------------------------------------------- */
.eyebrow{
  display:inline-flex;align-items:center;gap:.55rem;
  font-family:var(--font-mono);font-size:.72rem;letter-spacing:.2em;
  color:var(--gold-deep);text-transform:uppercase;
}
.eyebrow::before{
  content:"";width:26px;height:1px;flex:none;
  background:linear-gradient(90deg,var(--gold),rgba(201,162,39,0));
}
.section-title{
  font-family:var(--font-serif);
  font-size:clamp(1.7rem,3.4vw,2.4rem);
  line-height:1.3;color:var(--ink);
}
.lede{font-size:clamp(1.02rem,1.35vw,1.16rem);line-height:1.85;color:var(--ink-soft)}
.note{font-size:.83rem;line-height:1.7;color:var(--stone)}
.mono{font-family:var(--font-mono);font-variant-numeric:tabular-nums;letter-spacing:.03em}
.rule{
  border:0;height:1px;margin-block:clamp(1.6rem,3vw,2.6rem);
  background:linear-gradient(90deg,var(--line-gold),rgba(201,162,39,0));
}

/* 06 · buttons ------------------------------------------------- */
.btn{
  position:relative;
  display:inline-flex;align-items:center;justify-content:center;gap:.5rem;
  padding:.64rem 1.1rem;
  font-family:var(--font-sans);font-size:.9rem;line-height:1.3;letter-spacing:.04em;
  border:1px solid transparent;border-radius:3px;
  cursor:pointer;
  transition:background .22s var(--ease),color .22s var(--ease),
             border-color .22s var(--ease),transform .22s var(--ease);
}
.btn--primary{background:var(--cinnabar);color:#FFF7EC;box-shadow:inset 0 -2px 0 rgba(27,26,23,.22)}
.btn--primary:hover{background:var(--cinnabar-deep);transform:translateY(-1px)}
.btn--ghost{border-color:rgba(247,242,231,.36);color:rgba(247,242,231,.92)}
.btn--ghost:hover{border-color:var(--gold);color:var(--gold-bright);background:rgba(201,162,39,.1)}
.btn--quiet{
  padding:.18rem 0;border:0;border-bottom:1px solid var(--gold);
  border-radius:0;color:var(--copper-deep);font-size:.88rem;
}
.btn--quiet:hover{border-bottom-color:var(--cinnabar);color:var(--cinnabar)}
.btn--sm{font-size:.8rem;padding:.44rem .78rem}

/* 07 · breadcrumb ---------------------------------------------- */
.breadcrumb{padding-block:clamp(1.1rem,2.4vw,1.7rem) 0}
.breadcrumb-list{
  display:flex;flex-wrap:wrap;align-items:center;
  gap:.45rem;
  font-family:var(--font-mono);font-size:.72rem;letter-spacing:.08em;
  color:var(--stone);
}
.breadcrumb-list li{display:inline-flex;align-items:center;gap:.45rem}
.breadcrumb-list li + li::before{content:"/";color:rgba(122,92,62,.55)}
.breadcrumb-list a{color:var(--copper);border-bottom:1px solid transparent;transition:border-color .2s var(--ease)}
.breadcrumb-list a:hover{border-bottom-color:var(--gold)}
.breadcrumb-list [aria-current="page"]{
  display:inline-flex;align-items:center;gap:.4rem;color:var(--ink);
}
.breadcrumb-list [aria-current="page"]::before{
  content:"";width:5px;height:5px;border-radius:50%;background:var(--cinnabar);flex:none;
}

/* 08 · components ---------------------------------------------- */
.index-card{
  position:relative;
  padding:clamp(1rem,2vw,1.4rem) clamp(1rem,2.2vw,1.6rem);
  background:var(--paper);
  border:1px solid var(--line);
  border-left:3px solid var(--copper);
  border-radius:var(--radius-organic);
  box-shadow:var(--shadow-lift);
  transition:border-color .25s var(--ease),transform .25s var(--ease);
}
.index-card:hover{border-left-color:var(--cinnabar)}
.index-card__no{display:block;font-family:var(--font-mono);font-size:.72rem;letter-spacing:.16em;color:var(--gold-deep)}
.index-card__title{font-family:var(--font-serif);font-size:1.16rem;margin:.22rem 0 .35rem;color:var(--ink)}
.index-card__meta{display:block;font-family:var(--font-mono);font-size:.72rem;letter-spacing:.06em;color:var(--stone)}
.index-card__body{
  margin-top:.85rem;padding-top:.85rem;
  border-top:1px dashed var(--line);
  font-size:.94rem;line-height:1.8;color:var(--ink-soft);
}
.index-card[data-open="false"] .index-card__body{display:none}
.index-card[data-open="true"] .index-card__body{display:block}

.panel{
  padding:clamp(1.1rem,2.4vw,1.8rem);
  background:var(--mint);
  border-radius:var(--radius-organic);
  border:1px solid rgba(47,107,90,.16);
  color:var(--ink-soft);
}
.tag{
  display:inline-flex;align-items:center;gap:.35rem;
  padding:.16rem .5rem;border-radius:2px;
  font-family:var(--font-mono);font-size:.7rem;letter-spacing:.08em;
  background:rgba(47,107,90,.1);color:var(--copper-deep);
  border:1px solid rgba(47,107,90,.24);
}
.tag--gold{background:rgba(201,162,39,.15);color:var(--gold-deep);border-color:rgba(201,162,39,.42)}
.tag--alert{background:rgba(196,64,31,.1);color:var(--cinnabar);border-color:rgba(196,64,31,.3)}

.table-scroll{overflow-x:auto;border:1px solid var(--line);border-radius:var(--radius-soft);background:var(--paper)}
.ledger{min-width:560px;font-size:.92rem}
.ledger caption{
  padding:.7rem .9rem;text-align:left;
  font-family:var(--font-mono);font-size:.72rem;letter-spacing:.14em;
  color:var(--stone);background:var(--paper-2);
}
.ledger th{
  padding:.72rem .85rem;text-align:left;
  font-family:var(--font-mono);font-size:.72rem;font-weight:500;letter-spacing:.1em;
  color:var(--copper-deep);
  background:rgba(217,231,223,.62);
  border-bottom:1px solid var(--gold);
}
.ledger td{padding:.72rem .85rem;border-bottom:1px solid var(--line);vertical-align:top;color:var(--ink-soft)}
.ledger tbody tr:nth-child(even){background:rgba(217,231,223,.38)}
.ledger tbody tr:last-child td{border-bottom:0}

.media-frame{
  position:relative;overflow:hidden;
  aspect-ratio:16/10;
  border-radius:var(--radius-organic);
  background:linear-gradient(150deg,var(--mint) 0%,var(--paper-2) 58%,#D8C7A4 100%);
  box-shadow:var(--shadow-lift);
}
.media-frame img,.media-frame picture,.media-frame svg{
  width:100%;height:100%;object-fit:cover;
}
.media-frame::after{
  content:"";position:absolute;inset:0;pointer-events:none;
  background:repeating-linear-gradient(45deg,rgba(122,92,62,.07) 0 2px,transparent 2px 7px);
  mix-blend-mode:multiply;
}
.media-frame--wide{aspect-ratio:21/9}
.media-frame--tall{aspect-ratio:3/4}
.media-frame--square{aspect-ratio:1/1}
.media-frame__label{
  position:absolute;left:.8rem;top:.8rem;z-index:2;
  padding:.16rem .5rem;border-radius:2px;
  font-family:var(--font-mono);font-size:.68rem;letter-spacing:.1em;
  background:rgba(247,242,231,.9);color:var(--copper-deep);
  border:1px solid rgba(201,162,39,.5);
}

/* 09 · header -------------------------------------------------- */
.site-header{
  position:sticky;top:0;z-index:80;
  background:linear-gradient(180deg,#1A5142 0%,var(--copper-deep) 62%,#134034 100%);
  color:var(--paper);
  border-bottom:1px solid rgba(201,162,39,.42);
  box-shadow:0 14px 34px -30px rgba(0,0,0,.9);
}
.header-inner{
  width:min(calc(100% - 2 * var(--gutter)),var(--shell));
  margin-inline:auto;
  min-height:var(--header-h);
  display:flex;align-items:center;gap:clamp(.5rem,1.6vw,1.2rem);
  padding-block:.6rem;
}
.brand{
  display:inline-flex;align-items:center;gap:.62rem;flex:0 0 auto;
  color:var(--paper);text-decoration:none;
}
.brand-mark{
  position:relative;flex:none;
  width:36px;height:36px;border-radius:50%;
  background:radial-gradient(circle at 32% 26%,var(--gold-bright) 0%,var(--gold) 48%,#8F6F14 100%);
  box-shadow:inset 0 0 0 1px rgba(247,242,231,.55),0 2px 0 rgba(0,0,0,.22);
  transition:transform .3s var(--ease);
}
.brand:hover .brand-mark{transform:rotate(-8deg)}
.brand-mark::after{
  content:"";position:absolute;inset:0;margin:auto;
  width:11px;height:11px;border-radius:1px;
  background:var(--copper-deep);
  border:1px solid rgba(247,242,231,.5);
}
.brand-text{display:flex;flex-direction:column;line-height:1}
.brand-name{
  font-family:var(--font-serif);font-size:1.16rem;
  letter-spacing:.16em;color:var(--paper);
}
.brand-sub{
  margin-top:.3rem;
  font-family:var(--font-mono);font-size:.6rem;letter-spacing:.24em;
  color:rgba(247,242,231,.52);
}
.version-chip{
  flex:none;
  font-family:var(--font-mono);font-size:.66rem;letter-spacing:.12em;
  color:var(--gold-bright);
  padding:.1rem .34rem;
  border:1px solid rgba(201,162,39,.6);border-radius:2px;
}

.header-nav{margin-inline-start:auto}
.nav-list{display:flex;align-items:center;gap:.08rem}
.nav-link{
  position:relative;
  display:inline-flex;align-items:baseline;gap:.4rem;
  padding:.5rem .55rem;border-radius:3px;
  font-size:.87rem;letter-spacing:.02em;
  color:rgba(247,242,231,.78);
  transition:color .2s var(--ease),background .2s var(--ease);
}
.nav-index{
  font-family:var(--font-mono);font-size:.6rem;letter-spacing:.06em;
  color:rgba(201,162,39,.7);transition:color .2s var(--ease);
}
.nav-link::after{
  content:"";position:absolute;left:.55rem;right:.55rem;bottom:.24rem;height:1px;
  background:linear-gradient(90deg,var(--gold),var(--cinnabar));
  transform:scaleX(0);transform-origin:left;
  transition:transform .3s var(--ease);
}
.nav-link:hover{color:var(--paper);background:rgba(247,242,231,.07)}
.nav-link:hover .nav-index{color:var(--gold-bright)}
.nav-link:hover::after{transform:scaleX(1)}
.nav-link[aria-current="page"]{
  color:var(--paper);
  background:rgba(196,64,31,.18);
  box-shadow:inset 0 -2px 0 var(--cinnabar);
}
.nav-link[aria-current="page"] .nav-index{color:var(--cinnabar)}
.nav-link[aria-current="page"]::after{transform:scaleX(1);background:var(--cinnabar)}
.nav-link[aria-current="page"]::before{
  content:"";position:absolute;top:.3rem;right:.28rem;
  width:5px;height:5px;border-radius:50%;
  background:var(--cinnabar);
  box-shadow:0 0 0 3px rgba(196,64,31,.22);
}

.header-actions{
  display:flex;align-items:center;gap:.5rem;flex:0 0 auto;
  margin-inline-start:.35rem;
}
.nav-toggle{
  display:none;align-items:center;justify-content:center;
  flex-direction:column;gap:4px;
  width:42px;height:38px;
  border:1px solid rgba(201,162,39,.5);border-radius:3px;
  cursor:pointer;
  transition:border-color .2s var(--ease),background .2s var(--ease);
}
.nav-toggle:hover{border-color:var(--gold);background:rgba(201,162,39,.12)}
.nav-toggle-bar{
  display:block;width:17px;height:1.5px;background:var(--paper);
  transition:transform .26s var(--ease),opacity .2s var(--ease);
}
.nav-toggle[aria-expanded="true"]{border-color:var(--cinnabar);background:rgba(196,64,31,.2)}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(1){transform:translateY(5.5px) rotate(45deg)}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(2){opacity:0}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(3){transform:translateY(-5.5px) rotate(-45deg)}

.scroll-progress{
  position:absolute;left:0;right:0;bottom:-1px;height:2px;
  background:rgba(247,242,231,.14);
  pointer-events:none;
}
.scroll-progress__bar{
  display:block;height:100%;width:100%;
  transform:scaleX(0);transform-origin:0 50%;
  background:linear-gradient(90deg,var(--gold),var(--gold-bright) 42%,var(--cinnabar));
  transition:transform .12s linear;
}

/* 10 · footer -------------------------------------------------- */
.site-footer{
  position:relative;
  margin-top:clamp(3.5rem,8vw,7rem);
  padding-top:clamp(4.6rem,9vw,6.6rem);
  padding-bottom:1.6rem;
  background:linear-gradient(180deg,#1A5142 0%,var(--copper-deep) 46%,var(--copper-ink) 100%);
  color:rgba(247,242,231,.78);
}
.site-footer::before{
  content:"";position:absolute;top:-1px;left:0;right:0;
  height:clamp(26px,4vw,44px);
  background:var(--paper);
  border-radius:0 0 50% 50% / 0 0 100% 100%;
}
.site-footer .brand{color:var(--paper)}
.footer-top{
  display:grid;
  grid-template-columns:1.7fr .85fr .85fr .85fr 1.6fr;
  gap:clamp(1.2rem,3vw,2.6rem);
  align-items:start;
}
.footer-summary{
  margin-top:1rem;max-width:26ch;
  font-size:.87rem;line-height:1.8;color:rgba(247,242,231,.66);
}
.footer-col{min-width:0}
.foot-title{
  margin-bottom:.9rem;padding-bottom:.5rem;
  font-family:var(--font-mono);font-size:.7rem;font-weight:500;
  letter-spacing:.22em;color:var(--gold);
  border-bottom:1px solid rgba(201,162,39,.28);
}
.foot-list{display:grid;gap:.55rem}
.foot-link{
  display:inline-flex;align-items:center;gap:.5rem;
  font-size:.88rem;color:rgba(247,242,231,.78);
  transition:color .2s var(--ease),transform .2s var(--ease);
}
.foot-link::before{
  content:"";width:10px;height:1px;flex:none;
  background:rgba(201,162,39,.55);
  transition:width .22s var(--ease),background .22s var(--ease);
}
.foot-link:hover{color:var(--paper);transform:translateX(2px)}
.foot-link:hover::before{width:18px;background:var(--cinnabar)}

.footer-contact{display:grid;gap:.42rem;font-size:.86rem;line-height:1.7;min-width:0}
.foot-contact__line{
  display:grid;grid-template-columns:3.1rem minmax(0,1fr);gap:.5rem;
  color:rgba(247,242,231,.8);word-break:break-word;
}
.foot-contact__label{
  font-family:var(--font-mono);font-size:.66rem;letter-spacing:.12em;
  color:rgba(201,162,39,.85);padding-top:.18rem;
}
.foot-contact__note{
  margin-top:.5rem;padding-top:.6rem;
  font-size:.76rem;line-height:1.75;color:rgba(247,242,231,.54);
  border-top:1px dashed rgba(201,162,39,.25);
}
.footer-legal{
  margin-top:clamp(2rem,4vw,3rem);
  padding-top:1.1rem;
  border-top:1px solid rgba(201,162,39,.22);
  display:flex;flex-wrap:wrap;gap:.5rem 1.4rem;justify-content:space-between;
  font-family:var(--font-mono);font-size:.72rem;letter-spacing:.06em;
  color:rgba(247,242,231,.5);
}

/* 11 · responsive --------------------------------------------- */
@media (max-width:1240px){
  .header-secondary{display:none}
}
@media (max-width:1120px){
  .nav-toggle{display:inline-flex}
  .header-actions{margin-inline-start:auto}
  .header-nav{
    position:absolute;top:100%;left:0;right:0;
    margin:0;
    background:linear-gradient(180deg,#17483B 0%,#123529 100%);
    border-bottom:1px solid var(--line-gold);
    box-shadow:0 26px 44px -34px rgba(0,0,0,.9);
    max-height:0;overflow:hidden;visibility:hidden;
    transition:max-height .34s var(--ease),visibility .34s var(--ease);
  }
  .header-nav[data-open="true"]{
    max-height:min(74vh,540px);
    overflow-y:auto;visibility:visible;
  }
  .nav-list{flex-direction:column;align-items:stretch;gap:0;padding:.3rem 0 .9rem}
  .nav-list li + li{border-top:1px solid rgba(247,242,231,.08)}
  .nav-link{
    padding:.82rem var(--gutter);
    border-radius:0;font-size:.95rem;
    justify-content:flex-start;
  }
  .nav-link::after{display:none}
  .nav-link[aria-current="page"]{
    background:rgba(196,64,31,.15);
    box-shadow:inset 3px 0 0 var(--cinnabar);
  }
  .nav-link[aria-current="page"]::before{
    top:50%;right:auto;left:.45rem;
    margin-top:-2.5px;
  }
  .nav-index{font-size:.66rem}
  .split-editorial,.split-editorial--flip{grid-template-columns:minmax(0,1fr)}
  .footer-top{grid-template-columns:repeat(3,minmax(0,1fr))}
  .footer-brand{grid-column:1 / -1}
  .footer-contact{grid-column:1 / -1}
}
@media (max-width:780px){
  body{font-size:16px}
  .brand-sub{display:none}
  .brand-name{font-size:1.06rem;letter-spacing:.12em}
  .brand-mark{width:32px;height:32px}
  .version-chip{font-size:.62rem}
  .header-inner{padding-block:.5rem}
  .footer-top{grid-template-columns:repeat(2,minmax(0,1fr));gap:1.5rem 1.2rem}
  .footer-legal{flex-direction:column;gap:.4rem}
  .ledger{min-width:520px}
}
@media (max-width:480px){
  .header-actions .btn--primary{padding:.4rem .58rem;font-size:.76rem}
  .footer-contact{grid-column:1 / -1}
}

/* 12 · motion -------------------------------------------------- */
[data-reveal]{
  opacity:0;transform:translateY(14px);
  transition:opacity .6s var(--ease),transform .6s var(--ease);
}
[data-reveal].is-visible{opacity:1;transform: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;
  }
  [data-reveal]{opacity:1;transform:none}
  .scroll-progress__bar{transition:none}
}