:root{
  --night:#0A1A2A;
  --deep:#06101C;
  --lake:#37B7B3;
  --lake-soft:#8FE0DC;
  --amber:#E8A23A;
  --amber-soft:#F5C46B;
  --sand:#C9B9A4;
  --mist:#8FA6B8;
  --pale:#D8E4EA;
  --paper:#F4F7F8;

  --bg:var(--night);
  --fg:var(--pale);

  --line-lake:rgba(55,183,179,.28);
  --line-sand:rgba(201,185,164,.24);
  --surface:rgba(216,228,234,.05);
  --surface-2:rgba(216,228,234,.09);
  --glass:rgba(6,16,28,.78);

  --font-head:"Noto Sans SC","HarmonyOS Sans SC","PingFang SC",-apple-system,BlinkMacSystemFont,"Segoe UI","Microsoft YaHei",sans-serif;
  --font-body:"Noto Sans SC","PingFang SC",-apple-system,BlinkMacSystemFont,"Segoe UI","Microsoft YaHei",sans-serif;
  --font-mono:"IBM Plex Mono","JetBrains Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;

  --shell-max:1440px;
  --gutter:clamp(16px,4vw,40px);
  --cut-edge:18px;
  --radius-pill:999px;
  --ease:cubic-bezier(.22,.61,.36,1);
}

*,*::before,*::after{box-sizing:border-box;}
*{margin:0;}
html{
  -webkit-text-size-adjust:100%;
  scroll-behavior:smooth;
  scroll-padding-top:110px;
}
body{
  min-height:100vh;
  background:var(--bg);
  color:var(--fg);
  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%;}
a{color:inherit;text-decoration:none;}
button{font:inherit;color:inherit;background:none;border:0;cursor:pointer;}
ul,ol{list-style:none;padding:0;}
dl,dd,dt{margin:0;}
h1,h2,h3,h4{font-family:var(--font-head);font-weight:800;letter-spacing:-.02em;line-height:1.16;color:var(--paper);}
p{max-width:68ch;}
::selection{background:rgba(55,183,179,.35);color:var(--paper);}

:focus-visible{
  outline:2px solid var(--lake-soft);
  outline-offset:3px;
  border-radius:4px;
}

.skip-link{
  position:absolute;
  left:var(--gutter);
  top:-120px;
  z-index:120;
  padding:.6rem 1.1rem;
  border-radius:0 0 12px 12px;
  background:var(--amber);
  color:#06101C;
  font-family:var(--font-head);
  font-weight:800;
  font-size:.85rem;
  transition:top .18s var(--ease);
}
.skip-link:focus{top:0;}

/* ---------- header ---------- */
.site-header{
  position:sticky;
  top:0;
  z-index:80;
  padding:clamp(10px,1.5vw,18px) 0 0;
  background:linear-gradient(180deg,rgba(6,16,28,.97) 0%,rgba(10,26,42,.82) 56%,rgba(10,26,42,0) 100%);
}
.header-shell{
  width:100%;
  max-width:var(--shell-max);
  margin-inline:auto;
  padding-inline:var(--gutter);
}
.header-island{
  position:relative;
  display:flex;
  align-items:center;
  gap:clamp(10px,1.8vw,26px);
  min-height:64px;
  padding:8px clamp(12px,1.6vw,18px) 8px clamp(14px,1.8vw,20px);
  border:1px solid var(--line-lake);
  border-radius:var(--radius-pill);
  background:linear-gradient(120deg,rgba(6,16,28,.94) 0%,rgba(10,26,42,.82) 55%,rgba(12,40,50,.86) 100%);
  -webkit-backdrop-filter:blur(14px);
  backdrop-filter:blur(14px);
  box-shadow:0 18px 40px -30px rgba(0,0,0,.9),inset 0 1px 0 rgba(216,228,234,.08);
  transition:min-height .25s var(--ease),padding .25s var(--ease),box-shadow .25s var(--ease);
}
.site-header[data-condensed="true"] .header-island{
  min-height:52px;
  padding-top:5px;
  padding-bottom:5px;
  box-shadow:0 24px 48px -26px rgba(0,0,0,.96),inset 0 1px 0 rgba(216,228,234,.1);
}

.brand{
  display:inline-flex;
  align-items:center;
  gap:10px;
  flex:0 0 auto;
  color:var(--paper);
}
.brand-mark{
  position:relative;
  width:36px;
  height:36px;
  flex:0 0 auto;
  display:grid;
  place-items:center;
  background:linear-gradient(150deg,var(--lake-soft) 0%,var(--lake) 46%,var(--amber) 100%);
  clip-path:polygon(0 0,100% 0,100% 64%,64% 100%,0 100%);
}
.brand-mark::before{
  content:"平";
  font-family:var(--font-head);
  font-weight:800;
  font-size:17px;
  line-height:1;
  color:#06101C;
}
.brand-text{display:flex;flex-direction:column;line-height:1.15;}
.brand-name{
  font-family:var(--font-head);
  font-weight:800;
  font-size:1.02rem;
  letter-spacing:-.01em;
  color:var(--paper);
}
.brand-descriptor{
  font-family:var(--font-mono);
  font-size:.66rem;
  letter-spacing:.14em;
  color:var(--mist);
}

.nav-rail{
  flex:1 1 auto;
  display:flex;
  justify-content:center;
  min-width:0;
}
.nav-list{
  display:flex;
  align-items:center;
  gap:2px;
  flex-wrap:nowrap;
}
.nav-item{flex:0 0 auto;}
.nav-link{
  display:inline-block;
  padding:.44rem .78rem;
  border-radius:var(--radius-pill);
  font-size:.88rem;
  line-height:1.4;
  color:var(--pale);
  white-space:nowrap;
  transition:background-color .16s var(--ease),color .16s var(--ease),box-shadow .16s var(--ease);
}
.nav-link:hover{background:rgba(55,183,179,.14);color:var(--paper);}
.nav-link[aria-current="page"]{
  background:rgba(55,183,179,.18);
  color:var(--lake-soft);
  box-shadow:inset 0 0 0 1px rgba(55,183,179,.42);
}

.header-actions{
  display:flex;
  align-items:center;
  gap:10px;
  margin-left:auto;
  flex:0 0 auto;
}
.status-capsule{
  display:inline-flex;
  align-items:center;
  gap:7px;
  padding:.32rem .72rem;
  border:1px solid var(--line-sand);
  border-radius:var(--radius-pill);
  font-family:var(--font-mono);
  font-size:.68rem;
  letter-spacing:.06em;
  color:var(--mist);
  white-space:nowrap;
}
.status-dot{
  width:6px;
  height:6px;
  border-radius:50%;
  background:var(--amber);
  box-shadow:0 0 0 3px rgba(232,162,58,.18);
}

.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:.5rem;
  padding:.72rem 1.25rem;
  border:1px solid transparent;
  border-radius:var(--radius-pill);
  font-family:var(--font-head);
  font-weight:800;
  font-size:.9rem;
  letter-spacing:.01em;
  white-space:nowrap;
  transition:transform .18s var(--ease),background-color .18s var(--ease),color .18s var(--ease),border-color .18s var(--ease),box-shadow .18s var(--ease);
}
.btn-amber{
  background:linear-gradient(135deg,var(--amber) 0%,var(--amber-soft) 100%);
  color:#0A1A2A;
  box-shadow:0 10px 26px -16px rgba(232,162,58,.9);
}
.btn-amber:hover{transform:translateY(-1px);box-shadow:0 14px 30px -14px rgba(232,162,58,.75);}
.btn-ghost{
  border-color:var(--line-sand);
  color:var(--pale);
  background:rgba(216,228,234,.04);
}
.btn-ghost:hover{border-color:rgba(55,183,179,.55);color:var(--lake-soft);background:rgba(55,183,179,.12);}
.btn-sm{padding:.5rem .95rem;font-size:.82rem;}

.nav-toggle{
  display:none;
  align-items:center;
  gap:8px;
  padding:.44rem .82rem .44rem .68rem;
  border:1px solid var(--line-lake);
  border-radius:var(--radius-pill);
  color:var(--pale);
  font-size:.8rem;
  line-height:1.2;
  transition:border-color .16s var(--ease),color .16s var(--ease);
}
.nav-toggle:hover{border-color:rgba(55,183,179,.6);color:var(--paper);}
.nav-toggle-box{display:grid;gap:4px;width:16px;}
.nav-toggle-bar{
  display:block;
  height:2px;
  border-radius:2px;
  background:var(--lake-soft);
  transition:transform .2s var(--ease),background-color .2s var(--ease);
}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(1){transform:translateY(3px) rotate(45deg);}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(2){transform:translateY(-3px) rotate(-45deg);}
.nav-toggle-text{font-family:var(--font-mono);letter-spacing:.08em;}

.scroll-meter{
  position:absolute;
  left:0;
  right:0;
  bottom:0;
  height:2px;
  background:rgba(143,166,184,.14);
}
.scroll-meter-fill{
  display:block;
  width:100%;
  height:100%;
  transform:scaleX(0);
  transform-origin:0 50%;
  background:linear-gradient(90deg,var(--lake) 0%,var(--lake-soft) 55%,var(--amber) 100%);
  transition:transform .1s linear;
}

/* ---------- footer ---------- */
.site-footer{
  position:relative;
  margin-top:clamp(56px,8vw,110px);
  padding-block:clamp(40px,6vw,72px) 0;
  background:linear-gradient(180deg,var(--deep) 0%,#050C15 100%);
  color:var(--pale);
  overflow:hidden;
}
.site-footer::before{
  content:"";
  position:absolute;
  inset:0 0 auto 0;
  height:190px;
  background:radial-gradient(120% 100% at 12% 0%,rgba(55,183,179,.16),rgba(55,183,179,0) 62%);
  pointer-events:none;
}
.site-footer::after{
  content:"";
  position:absolute;
  left:-6%;
  right:-6%;
  top:0;
  height:1px;
  background:linear-gradient(90deg,rgba(232,162,58,0) 0%,rgba(232,162,58,.65) 22%,rgba(143,224,220,.5) 68%,rgba(232,162,58,0) 100%);
  pointer-events:none;
}
.footer-shell{
  position:relative;
  z-index:1;
  width:100%;
  max-width:var(--shell-max);
  margin-inline:auto;
  padding-inline:var(--gutter);
}
.footer-top{
  display:grid;
  grid-template-columns:minmax(230px,1.35fr) minmax(130px,.75fr) minmax(130px,.75fr) minmax(270px,1.5fr);
  gap:clamp(24px,3.5vw,48px);
  padding-bottom:clamp(30px,4vw,52px);
}
.footer-brand .brand{margin-bottom:14px;}
.brand--footer .brand-name{font-size:1.1rem;}
.footer-tagline{
  font-size:.95rem;
  line-height:1.7;
  color:var(--pale);
  max-width:34ch;
}
.footer-note{
  margin-top:10px;
  font-size:.78rem;
  line-height:1.7;
  color:var(--mist);
  max-width:44ch;
}
.footer-heading{
  font-family:var(--font-mono);
  font-size:.72rem;
  font-weight:700;
  letter-spacing:.18em;
  color:var(--lake-soft);
  margin-bottom:14px;
}
.footer-links{display:grid;gap:8px;}
.footer-link{
  display:inline-block;
  padding-block:2px;
  font-size:.9rem;
  color:var(--pale);
  border-bottom:1px solid transparent;
  transition:color .16s var(--ease),border-color .16s var(--ease),transform .16s var(--ease);
}
.footer-link:hover{
  color:var(--amber-soft);
  border-color:rgba(232,162,58,.6);
  transform:translateX(2px);
}
.footer-contact{padding:clamp(18px,2vw,24px);}
.contact-list{display:grid;gap:10px;}
.contact-row{
  display:grid;
  grid-template-columns:auto minmax(0,1fr);
  gap:10px;
  align-items:baseline;
}
.contact-label{
  font-family:var(--font-mono);
  font-size:.7rem;
  letter-spacing:.12em;
  color:var(--mist);
}
.contact-value{
  font-size:.86rem;
  line-height:1.6;
  color:var(--paper);
  overflow-wrap:anywhere;
}
.footer-base{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:14px 24px;
  padding-block:18px clamp(20px,3vw,28px);
  border-top:1px solid rgba(143,166,184,.16);
}
.footer-copy{
  font-family:var(--font-mono);
  font-size:.76rem;
  letter-spacing:.04em;
  color:var(--mist);
}
.footer-legal{display:flex;flex-wrap:wrap;gap:16px;}
.footer-legal-link{
  font-size:.78rem;
  color:var(--mist);
  transition:color .16s var(--ease);
}
.footer-legal-link:hover{color:var(--lake-soft);}
.footer-icp{
  margin-left:auto;
  font-family:var(--font-mono);
  font-size:.74rem;
  letter-spacing:.06em;
  color:var(--sand);
}

/* ---------- shared page primitives ---------- */
.container{
  width:100%;
  max-width:var(--shell-max);
  margin-inline:auto;
  padding-inline:var(--gutter);
}
#main-content{display:block;}

.breadcrumb{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:8px;
  padding-block:clamp(16px,2vw,26px);
  font-family:var(--font-mono);
  font-size:.72rem;
  letter-spacing:.1em;
  color:var(--mist);
}
.breadcrumb a{color:var(--mist);transition:color .16s var(--ease);}
.breadcrumb a:hover{color:var(--lake-soft);}
.breadcrumb-sep{color:rgba(143,166,184,.5);}
.breadcrumb [aria-current="page"]{color:var(--pale);}

.section{padding-block:clamp(44px,6vw,88px);}
.section-head{
  display:flex;
  flex-direction:column;
  gap:10px;
  margin-bottom:clamp(20px,3vw,36px);
  max-width:68ch;
}
.chapter-num{
  display:inline-flex;
  align-items:center;
  gap:8px;
  font-family:var(--font-mono);
  font-weight:700;
  font-size:.76rem;
  letter-spacing:.2em;
  color:var(--amber);
}
.section-title{font-size:clamp(1.7rem,3vw,2.6rem);color:var(--paper);}
.section-lead{
  font-size:1rem;
  line-height:1.8;
  color:var(--mist);
  max-width:62ch;
}

.slab{
  position:relative;
  --cut-edge:22px;
  background:linear-gradient(160deg,rgba(216,228,234,.08) 0%,rgba(216,228,234,.025) 100%);
  clip-path:polygon(0 0,calc(100% - var(--cut-edge)) 0,100% var(--cut-edge),100% 100%,var(--cut-edge) 100%,0 calc(100% - var(--cut-edge)));
  box-shadow:inset 0 1px 0 rgba(216,228,234,.1);
}

.media-frame{
  position:relative;
  overflow:hidden;
  --cut-edge:20px;
  background:linear-gradient(150deg,#0C2233 0%,#06101C 58%,#0A2430 100%);
  clip-path:polygon(0 0,calc(100% - var(--cut-edge)) 0,100% var(--cut-edge),100% 100%,var(--cut-edge) 100%,0 calc(100% - var(--cut-edge)));
}
.media-frame img{width:100%;height:100%;object-fit:cover;}
.media-frame::after{
  content:"";
  position:absolute;
  inset:0;
  background:linear-gradient(180deg,rgba(10,26,42,0) 42%,rgba(6,16,28,.72) 100%);
  pointer-events:none;
}
.media-frame--wide{aspect-ratio:21/9;}
.media-frame--4x3{aspect-ratio:4/3;}
.media-frame--square{aspect-ratio:1/1;}

.grid{display:grid;gap:clamp(16px,2vw,24px);}
.grid--2{grid-template-columns:repeat(2,minmax(0,1fr));}
.grid--3{grid-template-columns:repeat(3,minmax(0,1fr));}
.grid--asym{grid-template-columns:4fr 8fr;}

.chip{
  display:inline-flex;
  align-items:center;
  gap:6px;
  padding:.34rem .74rem;
  border:1px solid var(--line-sand);
  border-radius:var(--radius-pill);
  background:rgba(216,228,234,.04);
  font-size:.78rem;
  color:var(--pale);
  transition:background-color .18s var(--ease),border-color .18s var(--ease),color .18s var(--ease),transform .18s var(--ease);
}
.chip:hover{border-color:rgba(55,183,179,.5);color:var(--paper);}
.chip[aria-pressed="true"]{
  background:rgba(55,183,179,.18);
  border-color:rgba(55,183,179,.55);
  color:var(--lake-soft);
}
.badge{
  display:inline-flex;
  align-items:center;
  padding:.2rem .5rem;
  border-radius:6px;
  background:rgba(232,162,58,.18);
  color:var(--amber-soft);
  font-family:var(--font-mono);
  font-size:.68rem;
  letter-spacing:.1em;
}
.rule-oblique{
  height:1px;
  border:0;
  background:linear-gradient(90deg,rgba(55,183,179,0) 0%,rgba(55,183,179,.45) 30%,rgba(201,185,164,.35) 70%,rgba(201,185,164,0) 100%);
  transform:rotate(-1.2deg);
  transform-origin:left center;
}

.js [data-reveal]{
  opacity:0;
  transform:translateY(16px);
  transition:opacity .55s var(--ease),transform .55s var(--ease);
}
.js [data-reveal].is-revealed{opacity:1;transform:none;}

.to-top{
  position:fixed;
  right:clamp(14px,2.5vw,28px);
  bottom:clamp(14px,2.5vw,28px);
  z-index:70;
  display:inline-flex;
  align-items:center;
  gap:.5rem;
  padding:.6rem 1rem;
  border:1px solid var(--line-lake);
  border-radius:var(--radius-pill);
  background:rgba(6,16,28,.92);
  color:var(--pale);
  font-family:var(--font-mono);
  font-size:.76rem;
  letter-spacing:.08em;
  opacity:0;
  transform:translateY(10px);
  pointer-events:none;
  transition:opacity .2s var(--ease),transform .2s var(--ease),border-color .2s var(--ease);
}
.to-top[data-visible="true"]{
  opacity:1;
  transform:none;
  pointer-events:auto;
}
.to-top:hover{border-color:rgba(232,162,58,.65);color:var(--amber-soft);}
.to-top-arrow{color:var(--amber);}

/* ---------- responsive ---------- */
@media (max-width:1180px){
  .status-capsule{display:none;}
  .nav-link{padding:.44rem .62rem;font-size:.84rem;}
}
@media (max-width:980px){
  .nav-toggle{display:inline-flex;}
  .header-island{flex-wrap:nowrap;}
  .nav-rail{
    position:absolute;
    left:0;
    right:0;
    top:calc(100% + 10px);
    display:block;
    padding:10px;
    border:1px solid var(--line-lake);
    border-radius:24px;
    background:rgba(6,16,28,.97);
    -webkit-backdrop-filter:blur(16px);
    backdrop-filter:blur(16px);
    box-shadow:0 30px 60px -28px rgba(0,0,0,.95);
    opacity:0;
    visibility:hidden;
    transform:translateY(-8px);
    transition:opacity .2s var(--ease),transform .2s var(--ease),visibility .2s var(--ease);
  }
  .nav-rail[data-open="true"]{
    opacity:1;
    visibility:visible;
    transform:none;
  }
  .nav-list{flex-direction:column;align-items:stretch;gap:2px;}
  .nav-link{display:block;padding:.7rem .9rem;font-size:.95rem;border-radius:14px;}
  .footer-top{grid-template-columns:repeat(2,minmax(0,1fr));}
  .footer-contact{grid-column:1 / -1;}
  .grid--asym{grid-template-columns:1fr;}
  .grid--3{grid-template-columns:repeat(2,minmax(0,1fr));}
}
@media (max-width:640px){
  .brand-descriptor{display:none;}
  .brand-mark{width:32px;height:32px;}
  .brand-mark::before{font-size:15px;}
  .brand-name{font-size:.95rem;}
  .header-island{min-height:56px;gap:10px;}
  .btn-sm{padding:.45rem .8rem;font-size:.76rem;}
  .footer-top{grid-template-columns:1fr;}
  .footer-icp{margin-left:0;}
  .grid--2,.grid--3{grid-template-columns:1fr;}
}

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