:root{
  --c-void:#06090A;
  --c-night:#0C2B23;
  --c-cyan:#3DF5D0;
  --c-orange:#FF6A2A;
  --c-silver:#A7B4B0;
  --c-paper:#F3F5EE;
  --c-slate:#163A33;
  --c-amber:#F2C14E;
  --c-mist:#6E8F87;
  --c-rust:#7A2E12;

  --font-display:"Barlow Condensed","Oswald","Noto Sans SC","PingFang SC","Microsoft YaHei",sans-serif;
  --font-body:"PingFang SC","Noto Sans SC","Microsoft YaHei","Hiragino Sans GB",system-ui,-apple-system,sans-serif;
  --font-mono:"JetBrains Mono","DIN Alternate","Roboto Mono",ui-monospace,SFMono-Regular,"Courier New",monospace;

  --header-h:80px;
  --max-w:1440px;
  --gutter:clamp(18px,4vw,48px);
  --line:rgba(167,180,176,.22);
  --line-strong:rgba(167,180,176,.44);
  --radius:2px;
  --ease:cubic-bezier(.22,.61,.36,1);
  --shadow-stack:0 22px 48px -30px rgba(0,0,0,.95);
}

*,*::before,*::after{box-sizing:border-box;}

html{
  -webkit-text-size-adjust:100%;
  scroll-behavior:smooth;
  scroll-padding-top:calc(var(--header-h) + 18px);
}

body{
  margin:0;
  background-color:var(--c-void);
  color:var(--c-paper);
  font-family:var(--font-body);
  font-size:17px;
  line-height:1.75;
  overflow-x:hidden;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}

h1,h2,h3,h4,h5{
  margin:0;
  font-family:var(--font-display);
  font-weight:600;
  line-height:1.12;
  letter-spacing:-.02em;
  color:var(--c-paper);
}

p{margin:0 0 1.05em;}
p:last-child{margin-bottom:0;}
a{color:inherit;text-decoration:none;}
img,svg{display:block;max-width:100%;height:auto;}
ul,ol{margin:0;padding:0;list-style:none;}
button{font:inherit;color:inherit;background:none;border:0;}
table{border-collapse:collapse;width:100%;}

a:focus-visible,
button:focus-visible,
[tabindex]:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible{
  outline:2px solid var(--c-cyan);
  outline-offset:3px;
  border-radius:1px;
}

.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;
}

.page-main{display:block;padding-top:var(--header-h);}

.content-wrap{
  width:100%;
  max-width:var(--max-w);
  margin-inline:auto;
  padding-inline:var(--gutter);
}

.eyebrow{
  display:inline-flex;
  align-items:center;
  gap:10px;
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.22em;
  text-transform:uppercase;
  color:var(--c-cyan);
}
.eyebrow::before{
  content:"";
  width:22px;height:2px;
  background-color:var(--c-cyan);
  flex:0 0 auto;
}

.tag{
  display:inline-flex;
  align-items:center;
  gap:6px;
  padding:4px 10px;
  border:1px solid var(--line-strong);
  background-color:rgba(22,58,51,.55);
  color:var(--c-silver);
  font-family:var(--font-mono);
  font-size:10px;
  letter-spacing:.14em;
  text-transform:uppercase;
  transform:rotate(-1deg);
  transition:transform .2s var(--ease),color .2s var(--ease),border-color .2s var(--ease);
}
.tag:hover{transform:rotate(0deg);color:var(--c-paper);}
.tag--cyan{border-color:rgba(61,245,208,.55);color:var(--c-cyan);}
.tag--orange{border-color:rgba(255,106,42,.6);color:var(--c-orange);}
.tag--amber{border-color:rgba(242,193,78,.55);color:var(--c-amber);}

.breadcrumb{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:8px;
  padding:20px 0;
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.12em;
  color:var(--c-mist);
}
.breadcrumb a{color:var(--c-silver);transition:color .18s var(--ease);}
.breadcrumb a:hover{color:var(--c-cyan);}
.breadcrumb__sep{color:var(--c-mist);opacity:.55;}

.media-frame{
  position:relative;
  display:block;
  overflow:hidden;
  aspect-ratio:16/9;
  border:1px solid var(--line);
  background-color:var(--c-slate);
  background-image:linear-gradient(150deg,var(--c-slate),var(--c-void) 72%);
  box-shadow:var(--shadow-stack);
}
.media-frame img{
  width:100%;
  height:100%;
  object-fit:cover;
  filter:saturate(.92) contrast(1.06) brightness(.94);
  transition:transform .5s var(--ease);
}
.media-frame:hover img{transform:scale(1.03);}
.media-frame::after{
  content:"";
  position:absolute;
  inset:0;
  background-image:linear-gradient(180deg,rgba(6,9,10,0) 42%,rgba(6,9,10,.74) 100%);
  pointer-events:none;
}
.media-frame--wide{aspect-ratio:21/9;}
.media-frame--tall{aspect-ratio:3/4;}
.media-frame--square{aspect-ratio:1/1;}

.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:8px;
  padding:12px 20px;
  border:1px solid transparent;
  border-radius:var(--radius);
  font-family:var(--font-body);
  font-size:14px;
  font-weight:600;
  letter-spacing:.03em;
  line-height:1.2;
  cursor:pointer;
  transition:transform .2s var(--ease),background-color .2s var(--ease),color .2s var(--ease),border-color .2s var(--ease);
}
.btn--primary{
  background-color:var(--c-orange);
  border-color:var(--c-orange);
  color:#120703;
}
.btn--primary:hover{
  background-color:var(--c-amber);
  border-color:var(--c-amber);
  transform:translateY(-1px);
}
.btn--ghost{
  background-color:transparent;
  border-color:var(--line-strong);
  color:var(--c-paper);
}
.btn--ghost:hover{
  border-color:var(--c-cyan);
  color:var(--c-cyan);
  transform:translateY(-1px);
}

/* ---------- 头部 ---------- */
.skip-link{
  position:fixed;
  top:-120px;
  left:16px;
  z-index:300;
  padding:12px 20px;
  background-color:var(--c-cyan);
  color:var(--c-void);
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.1em;
  transition:top .22s var(--ease);
}
.skip-link:focus{top:12px;}

.site-header{
  position:fixed;
  top:0;left:0;right:0;
  z-index:120;
  color:var(--c-paper);
  background-color:transparent;
  border-bottom:1px solid transparent;
  transition:background-color .24s var(--ease),border-color .24s var(--ease),box-shadow .24s var(--ease);
}
.site-header[data-scrolled="true"]{
  background-color:rgba(12,43,35,.97);
  border-bottom-color:var(--line);
  box-shadow:0 14px 34px -26px rgba(0,0,0,1);
}

.site-header__inner{
  display:flex;
  align-items:center;
  gap:clamp(10px,2vw,26px);
  width:100%;
  max-width:var(--max-w);
  min-height:var(--header-h);
  margin-inline:auto;
  padding-inline:var(--gutter);
}

.brand{
  display:flex;
  align-items:center;
  gap:12px;
  flex:0 0 auto;
  padding:6px 0;
  color:inherit;
}
.brand__mark{
  position:relative;
  display:block;
  flex:0 0 auto;
  width:38px;
  height:32px;
  border:1px solid var(--line-strong);
  background-image:linear-gradient(158deg,rgba(61,245,208,.18),rgba(255,106,42,.14));
}
.brand__mark::before{
  content:"";
  position:absolute;
  top:0;bottom:0;left:50%;
  width:1px;
  margin-left:-.5px;
  background-color:var(--line-strong);
}
.brand__mark::after{
  content:"";
  position:absolute;
  top:50%;left:50%;
  width:11px;height:11px;
  margin:-5.5px 0 0 -5.5px;
  border:1.5px solid var(--c-cyan);
  border-radius:50%;
}
.brand__text{display:flex;flex-direction:column;line-height:1;}
.brand__cn{
  font-family:var(--font-display);
  font-size:21px;
  font-weight:600;
  letter-spacing:.06em;
  color:var(--c-paper);
}
.brand__en{
  margin-top:6px;
  font-family:var(--font-mono);
  font-size:10px;
  letter-spacing:.24em;
  text-transform:uppercase;
  color:var(--c-mist);
}

.site-nav{margin-left:auto;display:block;}
.site-nav__list{
  display:flex;
  align-items:center;
  gap:clamp(8px,1.5vw,26px);
}
.site-nav__item{flex:0 0 auto;}
.site-nav__link{
  position:relative;
  display:inline-block;
  padding:9px 2px;
  font-family:var(--font-body);
  font-size:15px;
  letter-spacing:.02em;
  white-space:nowrap;
  color:rgba(243,245,238,.8);
  transition:color .2s var(--ease);
}
.site-nav__link::after{
  content:"";
  position:absolute;
  left:0;bottom:2px;
  width:0;height:2px;
  background-color:var(--c-cyan);
  transition:width .24s var(--ease);
}
.site-nav__link:hover{color:var(--c-paper);}
.site-nav__link:hover::after{width:100%;}
.site-nav__link[aria-current="page"]{color:var(--c-cyan);}
.site-nav__link[aria-current="page"]::after{width:100%;}

.header__index{
  display:inline-flex;
  align-items:center;
  flex:0 0 auto;
  padding:6px 10px;
  border:1px dashed var(--line-strong);
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.14em;
  color:var(--c-amber);
  white-space:nowrap;
  transition:border-color .2s var(--ease),color .2s var(--ease);
}
.header__index:hover{border-color:var(--c-amber);color:var(--c-paper);}

.header__actions{
  display:flex;
  align-items:center;
  gap:10px;
  flex:0 0 auto;
}
.header__cta{white-space:nowrap;}

.nav-toggle{
  display:none;
  align-items:center;
  justify-content:center;
  flex-direction:column;
  gap:5px;
  width:46px;height:42px;
  padding:0;
  border:1px solid var(--line-strong);
  background-color:transparent;
  color:var(--c-paper);
  cursor:pointer;
  transition:border-color .2s var(--ease);
}
.nav-toggle:hover{border-color:var(--c-cyan);}
.nav-toggle__bar{
  display:block;
  width:20px;height:2px;
  background-color:currentColor;
  border-radius:1px;
  transition:transform .24s var(--ease),opacity .24s var(--ease);
}
.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(1){transform:translateY(7px) 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(-7px) rotate(-45deg);}

/* ---------- 页脚 ---------- */
.site-footer{
  position:relative;
  margin-top:clamp(64px,9vw,132px);
  background-color:var(--c-void);
  border-top:1px solid var(--line);
  color:var(--c-silver);
}
.site-footer::before{
  content:"";
  position:absolute;
  top:-1px;left:0;
  width:min(360px,42%);
  height:2px;
  background-image:linear-gradient(90deg,var(--c-cyan),var(--c-orange));
}

.site-footer__inner{
  display:grid;
  grid-template-columns:minmax(0,1fr) minmax(0,1.35fr);
  gap:clamp(32px,5vw,80px);
  width:100%;
  max-width:var(--max-w);
  margin-inline:auto;
  padding:clamp(44px,6vw,88px) var(--gutter) clamp(32px,4vw,54px);
}

.footer-brand{
  display:flex;
  flex-direction:column;
  gap:14px;
  max-width:430px;
}
.footer-brand__name{
  margin:0;
  font-family:var(--font-display);
  font-size:clamp(20px,2vw,26px);
  font-weight:600;
  letter-spacing:.02em;
  color:var(--c-paper);
}
.footer-brand__dot{margin:0 .5em;color:var(--c-orange);}
.footer-brand__summary{
  margin:0;
  font-size:14px;
  line-height:1.85;
  color:var(--c-silver);
}

.footer-contact{
  display:flex;
  flex-direction:column;
  gap:0;
  margin-top:6px;
}
.footer-contact__item{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:8px 12px;
  padding:11px 0;
  border-top:1px solid rgba(167,180,176,.16);
}
.footer-contact__label{
  flex:0 0 auto;
  font-family:var(--font-mono);
  font-size:10px;
  letter-spacing:.18em;
  text-transform:uppercase;
  color:var(--c-mist);
}
.footer-contact__value{
  font-family:var(--font-mono);
  font-size:13px;
  letter-spacing:.02em;
  color:var(--c-paper);
  word-break:break-all;
}
.footer-copy{
  margin-left:auto;
  padding:4px 10px;
  border:1px solid var(--line-strong);
  background-color:transparent;
  font-family:var(--font-mono);
  font-size:10px;
  letter-spacing:.14em;
  color:var(--c-silver);
  cursor:pointer;
  transition:color .2s var(--ease),border-color .2s var(--ease),background-color .2s var(--ease);
}
.footer-copy:hover{border-color:var(--c-cyan);color:var(--c-cyan);}
.footer-copy[data-copied="true"]{
  border-color:var(--c-cyan);
  background-color:rgba(61,245,208,.14);
  color:var(--c-cyan);
}
.footer-copy[data-copied="false"]{
  border-color:var(--c-orange);
  color:var(--c-orange);
}

.footer-nav{
  display:grid;
  grid-template-columns:repeat(3,minmax(0,1fr));
  gap:clamp(20px,3vw,40px);
}
.footer-nav__col{display:flex;flex-direction:column;gap:14px;}
.footer-nav__title{
  position:relative;
  margin:0;
  padding-top:14px;
  font-family:var(--font-mono);
  font-size:11px;
  font-weight:600;
  letter-spacing:.2em;
  text-transform:uppercase;
  color:var(--c-amber);
}
.footer-nav__title::before{
  content:"";
  position:absolute;
  top:0;left:0;
  width:26px;height:2px;
  background-color:var(--c-cyan);
}
.footer-nav__list{display:flex;flex-direction:column;gap:10px;}
.footer-nav__item{display:block;}
.footer-nav__link{
  display:inline-block;
  font-size:14px;
  color:var(--c-silver);
  transition:color .2s var(--ease),transform .2s var(--ease);
}
.footer-nav__link:hover{color:var(--c-cyan);transform:translateX(3px);}

.site-footer__base{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:10px 24px;
  width:100%;
  max-width:var(--max-w);
  margin-inline:auto;
  padding:18px var(--gutter) 28px;
  border-top:1px solid rgba(167,180,176,.16);
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.06em;
  color:var(--c-mist);
}
.site-footer__legal{margin:0;flex:1 1 320px;}
.site-footer__icp{margin:0;}
.site-footer__hours{margin:0;color:var(--c-silver);}

/* ---------- 长文辅助：章节目录 / 进度 / 回顶 ---------- */
.page-toc{
  padding:18px;
  border:1px solid var(--line);
  background-color:rgba(22,58,51,.38);
}
.page-toc__title{
  margin:0 0 12px;
  font-family:var(--font-mono);
  font-size:10px;
  letter-spacing:.2em;
  text-transform:uppercase;
  color:var(--c-amber);
}
.page-toc__list{display:flex;flex-direction:column;gap:2px;}
.page-toc__link{
  display:block;
  padding:8px 10px;
  border-left:2px solid transparent;
  font-size:13px;
  line-height:1.5;
  color:var(--c-silver);
  transition:color .16s var(--ease),border-color .16s var(--ease),background-color .16s var(--ease);
}
.page-toc__link:hover{color:var(--c-paper);background-color:rgba(61,245,208,.07);}
.page-toc__link.is-active,
.page-toc__link[aria-current="true"]{
  color:var(--c-cyan);
  border-left-color:var(--c-cyan);
  background-color:rgba(61,245,208,.1);
}

.progress-rail{
  position:absolute;
  left:0;right:0;bottom:-1px;
  height:2px;
  overflow:hidden;
  pointer-events:none;
}
.progress-rail__bar{
  display:block;
  width:0;
  height:100%;
  background-image:linear-gradient(90deg,var(--c-cyan),var(--c-amber),var(--c-orange));
  transition:width .1s linear;
}

.to-top{
  position:fixed;
  right:clamp(14px,3vw,32px);
  bottom:clamp(14px,3vw,32px);
  z-index:110;
  display:inline-flex;
  align-items:center;
  gap:8px;
  padding:10px 14px;
  border:1px solid var(--line-strong);
  background-color:rgba(12,43,35,.94);
  color:var(--c-paper);
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.14em;
  cursor:pointer;
  opacity:0;
  visibility:hidden;
  transform:translateY(8px);
  transition:opacity .24s var(--ease),transform .24s var(--ease),visibility .24s var(--ease),color .2s var(--ease),border-color .2s var(--ease);
}
.to-top[data-visible="true"]{opacity:1;visibility:visible;transform:none;}
.to-top:hover{border-color:var(--c-cyan);color:var(--c-cyan);}

/* ---------- 响应式 ---------- */
@media (max-width:1180px){
  .header__index{display:none;}
}

@media (max-width:1040px){
  .site-header__inner{gap:10px;}
  .header__cta{display:none;}
  .nav-toggle{display:inline-flex;margin-left:auto;}
  .site-nav{
    position:fixed;
    top:var(--header-h);
    left:0;right:0;bottom:0;
    display:flex;
    flex-direction:column;
    margin:0;
    padding:22px var(--gutter) 48px;
    background-color:var(--c-night);
    border-top:1px solid var(--line);
    overflow-y:auto;
    opacity:0;
    visibility:hidden;
    transform:translateY(-10px);
    transition:opacity .22s var(--ease),transform .22s var(--ease),visibility .22s var(--ease);
  }
  .site-nav[data-open="true"]{
    opacity:1;
    visibility:visible;
    transform:none;
  }
  .site-nav__list{
    flex-direction:column;
    align-items:stretch;
    gap:0;
    width:100%;
  }
  .site-nav__item{border-bottom:1px solid rgba(167,180,176,.14);}
  .site-nav__link{
    display:block;
    padding:16px 0;
    font-family:var(--font-display);
    font-size:19px;
    letter-spacing:.04em;
  }
  .site-nav__link::after{bottom:10px;}
  body.nav-open{overflow:hidden;}
}

@media (max-width:900px){
  .site-footer__inner{grid-template-columns:minmax(0,1fr);gap:38px;}
  .footer-brand{max-width:none;}
}

@media (max-width:720px){
  :root{--header-h:66px;}
  body{font-size:16px;}
  .brand__mark{width:32px;height:28px;}
  .brand__cn{font-size:18px;}
  .brand__en{font-size:9px;letter-spacing:.2em;}
  .site-footer__base{flex-direction:column;align-items:flex-start;}
  .to-top{padding:9px 12px;font-size:10px;}
}

@media (max-width:620px){
  .footer-nav{grid-template-columns:repeat(2,minmax(0,1fr));gap:22px 18px;}
  .footer-contact__item{gap:6px 10px;}
  .footer-copy{margin-left:0;}
}

@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto;}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
  }
  .media-frame:hover img{transform:none;}
  .to-top{transform:none;}
}