/* =========================================================
   changcheng-arena.com.cn — /assets/site.css
   Shared shell: reset / tokens / header / footer / base UI
   ========================================================= */

/* ---------- 1. tokens ---------- */
:root{
  --brick:#3E3C38;
  --mortar-deep:#262521;
  --mortar-light:#EFEBE1;
  --pitch:#2E6B45;
  --pitch-soft:#7FA98C;
  --stoppage:#D6412B;
  --data-blue:#2B6FA6;
  --scoreboard:#16161A;
  --index-gray:#9A958A;

  --seam:rgba(239,235,225,.16);
  --seam-dark:rgba(38,37,33,.16);

  --font-display:"Archivo Black","Noto Sans SC","Source Han Sans SC",system-ui,sans-serif;
  --font-mono:"IBM Plex Mono","JetBrains Mono",ui-monospace,SFMono-Regular,Menlo,monospace;
  --font-body:"Source Han Sans SC","Noto Sans SC","PingFang SC",system-ui,sans-serif;

  --step-1:clamp(1.9rem,4.6vw,2.6rem);
  --step-2:clamp(1.4rem,3.2vw,2rem);
  --step-3:clamp(1.12rem,2.2vw,1.5rem);

  --dur:.16s;
  --ease:ease;
}

/* ---------- 2. reset ---------- */
*,*::before,*::after{box-sizing:border-box}

html{
  -webkit-text-size-adjust:100%;
  scroll-behavior:smooth;
  scroll-padding-top:6.5rem;
}

body{
  margin:0;
  min-height:100%;
  font-family:var(--font-body);
  font-size:1rem;
  line-height:1.75;
  color:var(--mortar-light);
  background-color:var(--brick);
  background-image:repeating-linear-gradient(
    180deg,
    rgba(239,235,225,.04) 0 1px,
    transparent 1px 48px
  );
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}

h1,h2,h3,h4,h5,h6,p,ul,ol,dl,dd,figure,blockquote{margin:0}
ul,ol{padding:0;list-style:none}
img,svg,video{display:block;max-width:100%}
button{font:inherit;color:inherit;background:none;border:0;cursor:pointer}
table{border-collapse:collapse;width:100%}

a{
  color:var(--pitch-soft);
  text-decoration:none;
  transition:color var(--dur) var(--ease);
}
a:hover{color:var(--mortar-light)}

:focus-visible{
  outline:3px solid var(--stoppage);
  outline-offset:2px;
}

/* ---------- 3. type utilities ---------- */
.mono{
  font-family:var(--font-mono);
  font-variant-numeric:tabular-nums;
  letter-spacing:.01em;
}

.display-1{
  font-family:var(--font-display);
  font-weight:900;
  font-size:var(--step-1);
  line-height:1.1;
  letter-spacing:-.02em;
}
.display-2{
  font-family:var(--font-display);
  font-weight:900;
  font-size:var(--step-2);
  line-height:1.14;
  letter-spacing:-.015em;
}
.display-3{
  font-family:var(--font-display);
  font-weight:900;
  font-size:var(--step-3);
  line-height:1.2;
  letter-spacing:-.01em;
}
.lede{
  font-size:clamp(1rem,1.6vw,1.14rem);
  line-height:1.8;
  color:rgba(239,235,225,.78);
}

/* ---------- 4. containers & layout ---------- */
.container{
  width:100%;
  max-width:1360px;
  margin-inline:auto;
  padding-inline:clamp(1rem,3.5vw,2.5rem);
}
.container--narrow{max-width:880px}
.container--text{max-width:720px}

.section{
  padding-block:clamp(2.5rem,6vw,5rem);
  border-bottom:1px solid var(--seam);
}
.section--paper{
  background-color:var(--mortar-light);
  color:var(--mortar-deep);
  border-bottom:3px solid var(--mortar-deep);
}
.section--paper a{color:var(--pitch)}
.section--paper a:hover{color:var(--stoppage)}
.section--scoreboard{
  background-color:var(--scoreboard);
  border-bottom:3px solid var(--mortar-deep);
}

.section-head{
  display:flex;
  flex-wrap:wrap;
  align-items:flex-end;
  justify-content:space-between;
  gap:.9rem 1.6rem;
  margin-bottom:clamp(1.4rem,3vw,2.2rem);
  padding-bottom:1rem;
  border-bottom:2px solid var(--seam);
}
.section--paper .section-head{border-bottom-color:var(--seam-dark)}

.seam-rule{
  height:0;
  border:0;
  border-top:1px solid var(--seam);
  margin-block:clamp(1.5rem,3vw,2.5rem);
}
.section--paper .seam-rule{border-top-color:var(--seam-dark)}

.grid{display:grid;gap:clamp(1rem,2.4vw,1.8rem)}
.grid--2{grid-template-columns:repeat(2,minmax(0,1fr))}
.grid--3{grid-template-columns:repeat(3,minmax(0,1fr))}
.grid--4{grid-template-columns:repeat(4,minmax(0,1fr))}

.eyebrow{
  display:inline-flex;
  align-items:center;
  gap:.55rem;
  font-family:var(--font-mono);
  font-size:.7rem;
  letter-spacing:.16em;
  text-transform:uppercase;
  color:var(--pitch-soft);
}
.eyebrow::before{
  content:"";
  width:22px;
  height:2px;
  flex:none;
  background-color:currentColor;
}
.section--paper .eyebrow{color:var(--pitch)}

/* ---------- 5. header shell ---------- */
.site-header{
  position:sticky;
  top:0;
  z-index:80;
  color:var(--mortar-light);
  background-color:var(--brick);
  background-image:repeating-linear-gradient(
    180deg,
    rgba(239,235,225,.05) 0 1px,
    transparent 1px 40px
  );
  border-bottom:3px solid var(--mortar-deep);
}

.skip-link{
  position:absolute;
  left:clamp(1rem,3.5vw,2.5rem);
  top:-140px;
  z-index:20;
  padding:.6rem 1rem;
  border:3px solid var(--mortar-light);
  background-color:var(--stoppage);
  color:var(--mortar-light);
  font-family:var(--font-mono);
  font-size:.78rem;
  letter-spacing:.08em;
  transition:top var(--dur) var(--ease);
}
.skip-link:focus,
.skip-link:focus-visible{
  top:.4rem;
  color:var(--mortar-light);
}

.header-shell{
  display:flex;
  flex-wrap:nowrap;
  align-items:center;
  gap:clamp(.6rem,1.8vw,1.5rem);
  width:100%;
  max-width:1360px;
  margin-inline:auto;
  padding:.7rem clamp(1rem,3.5vw,2.5rem);
}

/* brand */
.brand{
  order:1;
  flex:0 0 auto;
  display:inline-flex;
  align-items:center;
  gap:.7rem;
  padding:.28rem .55rem .28rem .3rem;
  border:2px solid transparent;
  color:var(--mortar-light);
  transition:border-color var(--dur) var(--ease),background-color var(--dur) var(--ease);
}
.brand:hover,
.brand:focus-visible{
  border-color:var(--pitch);
  background-color:rgba(46,107,69,.2);
  color:var(--mortar-light);
}
.brand-mark{
  width:34px;
  height:34px;
  flex:0 0 34px;
  background-color:var(--mortar-deep);
  background-image:
    repeating-linear-gradient(0deg,var(--mortar-light) 0 2px,transparent 2px 9px),
    repeating-linear-gradient(90deg,var(--mortar-light) 0 2px,transparent 2px 17px);
  border:2px solid var(--mortar-light);
}
.brand-name{
  display:flex;
  flex-direction:column;
  gap:.05rem;
  min-width:0;
  line-height:1.15;
}
.brand-cn{
  font-family:var(--font-display);
  font-weight:900;
  font-size:1.02rem;
  letter-spacing:.02em;
  white-space:nowrap;
}
.brand-domain{
  font-family:var(--font-mono);
  font-size:.6rem;
  letter-spacing:.09em;
  color:var(--index-gray);
  white-space:nowrap;
}

/* floating capsule nav */
.site-nav{
  order:2;
  flex:1 1 auto;
  display:flex;
  justify-content:center;
  min-width:0;
}
.nav-list{
  display:flex;
  align-items:center;
  gap:.1rem;
  padding:.3rem;
  border:2px solid var(--mortar-deep);
  border-radius:999px;
  background-color:rgba(22,22,26,.6);
  box-shadow:0 5px 0 rgba(0,0,0,.34);
}
.nav-list a{
  display:block;
  padding:.42rem .88rem;
  border-radius:999px;
  font-size:.84rem;
  letter-spacing:.03em;
  white-space:nowrap;
  color:var(--mortar-light);
  transition:background-color var(--dur) var(--ease),color var(--dur) var(--ease);
}
.nav-list a:hover,
.nav-list a:focus-visible{
  background-color:var(--pitch);
  color:var(--mortar-light);
}
.nav-list a[aria-current="page"]{
  background-color:var(--pitch);
  color:var(--mortar-light);
  box-shadow:inset 0 0 0 2px rgba(239,235,225,.24);
}

/* status island */
.header-status{
  order:3;
  flex:0 0 auto;
  display:inline-flex;
  align-items:center;
  gap:.45rem;
  padding:.34rem .62rem;
  border:1px solid rgba(239,235,225,.22);
  font-family:var(--font-mono);
  font-size:.68rem;
  letter-spacing:.06em;
  color:var(--index-gray);
  white-space:nowrap;
}
.status-dot{
  width:9px;
  height:9px;
  flex:0 0 9px;
  background-color:var(--stoppage);
  box-shadow:0 0 0 2px rgba(214,65,43,.26);
}
.status-count{color:var(--mortar-light)}

/* mobile toggle */
.nav-toggle{
  order:4;
  display:none;
  align-items:center;
  gap:.5rem;
  padding:.44rem .72rem;
  border:2px solid var(--mortar-light);
  background-color:var(--mortar-deep);
  color:var(--mortar-light);
  font-family:var(--font-mono);
  font-size:.72rem;
  letter-spacing:.08em;
  transition:background-color var(--dur) var(--ease),border-color var(--dur) var(--ease);
}
.nav-toggle:hover{border-color:var(--pitch-soft)}
.nav-toggle-bars{
  position:relative;
  display:block;
  width:18px;
  height:2px;
  flex:0 0 18px;
  background-color:var(--mortar-light);
}
.nav-toggle-bars::before,
.nav-toggle-bars::after{
  content:"";
  position:absolute;
  left:0;
  width:18px;
  height:2px;
  background-color:var(--mortar-light);
  transition:transform var(--dur) var(--ease),opacity var(--dur) var(--ease);
}
.nav-toggle-bars::before{top:-5px}
.nav-toggle-bars::after{top:5px}
.nav-toggle[aria-expanded="true"] .nav-toggle-bars{background-color:transparent}
.nav-toggle[aria-expanded="true"] .nav-toggle-bars::before{transform:translateY(5px) rotate(45deg)}
.nav-toggle[aria-expanded="true"] .nav-toggle-bars::after{transform:translateY(-5px) rotate(-45deg)}
.nav-toggle-label{white-space:nowrap}

/* scroll progress */
.header-progress{
  position:absolute;
  left:0;
  bottom:0;
  width:100%;
  height:3px;
  background-color:var(--stoppage);
  transform:scaleX(0);
  transform-origin:0 50%;
  will-change:transform;
}

/* ---------- 6. footer shell ---------- */
.site-footer{
  margin-top:clamp(3.5rem,9vw,7rem);
  color:var(--mortar-light);
  background-color:var(--mortar-deep);
  background-image:repeating-linear-gradient(
    180deg,
    rgba(239,235,225,.035) 0 1px,
    transparent 1px 52px
  );
  border-top:4px solid var(--brick);
}
.footer-shell{
  width:100%;
  max-width:1360px;
  margin-inline:auto;
  padding:clamp(2.4rem,5.5vw,4.2rem) clamp(1rem,3.5vw,2.5rem) 1.6rem;
}
.footer-grid{
  display:grid;
  grid-template-columns:minmax(0,1.5fr) repeat(3,minmax(0,1fr));
  gap:clamp(1.6rem,3.5vw,3.2rem);
}
.footer-col{min-width:0}

.footer-brand{
  font-family:var(--font-display);
  font-weight:900;
  font-size:1.2rem;
  letter-spacing:.02em;
}
.footer-note{
  margin-top:.7rem;
  max-width:32ch;
  font-size:.88rem;
  line-height:1.7;
  color:var(--index-gray);
}
.footer-cta{
  display:inline-flex;
  margin-top:1.15rem;
}

.footer-heading{
  margin-bottom:.9rem;
  padding-bottom:.55rem;
  border-bottom:1px solid rgba(239,235,225,.18);
  font-family:var(--font-mono);
  font-size:.7rem;
  font-weight:400;
  letter-spacing:.16em;
  text-transform:uppercase;
  color:var(--pitch-soft);
}

.footer-links{
  display:flex;
  flex-direction:column;
  gap:.32rem;
}
.footer-links a{
  position:relative;
  display:inline-block;
  padding:.15rem 0;
  font-size:.92rem;
  color:var(--mortar-light);
  transition:color var(--dur) var(--ease);
}
.footer-links a::after{
  content:"";
  position:absolute;
  left:0;
  bottom:0;
  width:100%;
  height:1px;
  background-color:var(--pitch-soft);
  transform:scaleX(0);
  transform-origin:0 50%;
  transition:transform var(--dur) var(--ease);
}
.footer-links a:hover,
.footer-links a:focus-visible{color:var(--pitch-soft)}
.footer-links a:hover::after,
.footer-links a:focus-visible::after{transform:scaleX(1)}

.footer-contact{
  display:flex;
  flex-direction:column;
  gap:.34rem;
  margin-top:1.15rem;
  padding-top:1rem;
  border-top:1px solid rgba(239,235,225,.14);
}
.footer-meta-line{
  font-size:.8rem;
  line-height:1.6;
  color:var(--index-gray);
  word-break:break-word;
}
.footer-meta-line.mono{font-size:.76rem;letter-spacing:.02em}

.footer-base{
  display:flex;
  flex-wrap:wrap;
  align-items:baseline;
  justify-content:space-between;
  gap:.6rem 1.8rem;
  margin-top:clamp(2.2rem,4.5vw,3.4rem);
  padding-top:1.1rem;
  border-top:1px solid rgba(239,235,225,.18);
  font-size:.76rem;
  color:var(--index-gray);
}

/* ---------- 7. shared UI components ---------- */
.breadcrumb{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:.5rem;
  padding-block:.95rem;
  border-bottom:1px solid var(--seam);
  font-family:var(--font-mono);
  font-size:.72rem;
  letter-spacing:.08em;
  color:var(--index-gray);
}
.breadcrumb li{
  display:inline-flex;
  align-items:center;
  gap:.5rem;
}
.breadcrumb li + li::before{
  content:"/";
  color:var(--seam);
}
.breadcrumb a{color:var(--index-gray)}
.breadcrumb a:hover{color:var(--mortar-light)}
.breadcrumb [aria-current="page"]{color:var(--pitch-soft)}

.btn{
  display:inline-flex;
  align-items:center;
  gap:.5rem;
  padding:.68rem 1.15rem;
  border:3px solid var(--mortar-deep);
  background-color:var(--mortar-light);
  color:var(--mortar-deep);
  font-family:var(--font-mono);
  font-size:.78rem;
  letter-spacing:.08em;
  line-height:1.2;
  transition:background-color var(--dur) var(--ease),color var(--dur) var(--ease),
             border-color var(--dur) var(--ease),transform var(--dur) var(--ease);
}
.btn:hover,
.btn:focus-visible{
  background-color:var(--stoppage);
  border-color:var(--stoppage);
  color:var(--mortar-light);
  transform:translateY(-2px);
}
.btn--solid{
  background-color:var(--pitch);
  border-color:var(--pitch);
  color:var(--mortar-light);
}
.btn--solid:hover,
.btn--solid:focus-visible{
  background-color:var(--mortar-deep);
  border-color:var(--mortar-deep);
  color:var(--mortar-light);
}
.btn--ghost{
  background-color:transparent;
  border-color:var(--mortar-light);
  color:var(--mortar-light);
}
.btn--ghost:hover,
.btn--ghost:focus-visible{
  background-color:var(--stoppage);
  border-color:var(--stoppage);
  color:var(--mortar-light);
}
.btn--sm{
  padding:.45rem .82rem;
  border-width:2px;
  font-size:.72rem;
}

.tag{
  display:inline-flex;
  align-items:center;
  padding:.16rem .55rem;
  border:1px solid currentColor;
  font-family:var(--font-mono);
  font-size:.68rem;
  letter-spacing:.1em;
  text-transform:uppercase;
  color:var(--pitch-soft);
  white-space:nowrap;
}
.tag--alert{color:var(--stoppage)}
.tag--data{color:var(--data-blue)}

.stat{
  display:flex;
  flex-direction:column;
  gap:.25rem;
}
.stat__value{
  font-family:var(--font-mono);
  font-size:clamp(1.9rem,4.5vw,2.8rem);
  font-weight:600;
  line-height:1;
  letter-spacing:-.02em;
  color:var(--stoppage);
}
.stat__label{
  font-family:var(--font-mono);
  font-size:.7rem;
  letter-spacing:.12em;
  text-transform:uppercase;
  color:var(--index-gray);
}

.card{
  display:flex;
  flex-direction:column;
  gap:.7rem;
  padding:clamp(1.1rem,2.4vw,1.6rem);
  background-color:var(--mortar-light);
  color:var(--mortar-deep);
  border:3px solid var(--mortar-deep);
  box-shadow:8px 8px 0 rgba(0,0,0,.35);
  transition:transform var(--dur) var(--ease),box-shadow var(--dur) var(--ease),
             border-color var(--dur) var(--ease);
}
.card:hover,
.card:focus-within{
  transform:translate(-2px,-2px);
  border-color:var(--stoppage);
  box-shadow:10px 10px 0 rgba(0,0,0,.4);
}
.card--dark{
  background-color:var(--scoreboard);
  color:var(--mortar-light);
  border-color:var(--mortar-deep);
}
.card--dark a{color:var(--pitch-soft)}
.card--dark a:hover{color:var(--mortar-light)}

.prose{
  max-width:68ch;
  font-size:1.03rem;
  line-height:1.78;
}
.prose > * + *{margin-top:1.05em}
.prose h2{
  font-family:var(--font-display);
  font-weight:900;
  font-size:var(--step-3);
  line-height:1.24;
  letter-spacing:-.01em;
  margin-top:2em;
}
.prose h3{
  font-family:var(--font-display);
  font-weight:900;
  font-size:1.12rem;
  line-height:1.35;
  margin-top:1.6em;
}
.prose ul{
  display:flex;
  flex-direction:column;
  gap:.55rem;
}
.prose ul li{
  position:relative;
  padding-left:1.4rem;
}
.prose ul li::before{
  content:"";
  position:absolute;
  left:0;
  top:.72em;
  width:9px;
  height:2px;
  background-color:var(--pitch-soft);
}
.prose code{
  font-family:var(--font-mono);
  font-size:.88em;
  padding:.1em .35em;
  color:var(--data-blue);
  background-color:rgba(43,111,166,.12);
}

/* ---------- 8. figure / image frame ---------- */
.figure-frame{
  display:flex;
  flex-direction:column;
  margin:0;
  min-width:0;
  border:3px solid var(--mortar-deep);
  background-color:var(--mortar-light);
  box-shadow:9px 9px 0 var(--mortar-deep);
}
.figure-frame__media{
  position:relative;
  overflow:hidden;
  aspect-ratio:16 / 10;
  background-color:var(--brick);
  background-image:
    repeating-linear-gradient(0deg,rgba(239,235,225,.11) 0 1px,transparent 1px 26px),
    repeating-linear-gradient(90deg,rgba(239,235,225,.07) 0 1px,transparent 1px 54px);
}
.figure-frame__media img{
  width:100%;
  height:100%;
  object-fit:cover;
  filter:saturate(.72) contrast(1.06);
}
.figure-frame__media--wide{aspect-ratio:21 / 9}
.figure-frame__media--tall{aspect-ratio:3 / 4}
.figure-frame__media--square{aspect-ratio:1 / 1}

.figure-frame__caption{
  padding:.7rem .9rem;
  border-top:3px solid var(--mortar-deep);
  font-size:.78rem;
  line-height:1.6;
  color:var(--mortar-deep);
}
.figure-frame__caption .mono{color:var(--pitch)}

/* ---------- 9. responsive ---------- */
@media (max-width:1024px){
  .footer-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
}

@media (max-width:900px){
  .header-shell{
    flex-wrap:wrap;
    gap:.6rem;
    padding-block:.7rem;
  }
  .brand{order:1;flex:1 1 auto;min-width:0}
  .header-status{order:2;margin-left:0}
  .nav-toggle{order:3;display:inline-flex}
  .site-nav{
    order:4;
    flex:1 0 100%;
    justify-content:flex-start;
    display:none;
    padding-top:.2rem;
  }
  .site-nav[data-open="true"]{display:flex}
  .nav-list{
    flex-direction:column;
    align-items:stretch;
    width:100%;
    gap:.2rem;
    padding:.45rem;
    border-radius:0;
    box-shadow:0 6px 0 rgba(0,0,0,.34);
  }
  .nav-list a{
    padding:.7rem .9rem;
    border-radius:0;
    border-left:3px solid transparent;
    font-size:.95rem;
  }
  .nav-list a:hover,
  .nav-list a:focus-visible,
  .nav-list a[aria-current="page"]{
    border-left-color:var(--mortar-light);
  }

  .grid--3,
  .grid--4{grid-template-columns:repeat(2,minmax(0,1fr))}
}

@media (max-width:620px){
  :root{--dur:.14s}
  .grid--2,
  .grid--3,
  .grid--4{grid-template-columns:minmax(0,1fr)}
  .footer-grid{grid-template-columns:minmax(0,1fr)}
  .footer-base{justify-content:flex-start}
  .figure-frame{box-shadow:5px 5px 0 var(--mortar-deep)}
  .figure-frame__media{aspect-ratio:4 / 3}
}

/* ---------- 10. motion preferences ---------- */
@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto}
  *,
  *::before,
  *::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
  }
  .card:hover,
  .card:focus-within,
  .btn:hover,
  .btn:focus-visible{transform:none}
}