/* ============================================================
   MEIGAO COREHUB · site.css
   01 tokens / 02 reset / 03 typography / 04 shared components
   05 header / 06 footer / 07 responsive / 08 reduced motion
   ============================================================ */

/* ---------- 01 tokens ---------- */
:root{
  --navy-900:#0A1A2A;
  --navy-800:#0F2336;
  --navy-600:#183A52;
  --teal-deep:#0E3B3A;
  --wine:#4A1F2F;
  --indigo:#241B4A;
  --amber:#E2A94B;
  --amber-light:#F2C879;
  --celadon:#7FBFA8;
  --celadon-dark:#2F6F5E;
  --paper:#FBFAF6;
  --ivory:#F4F1EA;
  --ink:#141B22;
  --slate:#5E6B78;
  --line:#C9C3B6;

  --on-dark:rgba(244,241,234,.78);
  --on-dark-dim:rgba(244,241,234,.56);
  --on-dark-faint:rgba(244,241,234,.38);
  --hairline:rgba(24,58,82,.9);

  --font-heading:"HarmonyOS Sans SC","Source Han Sans SC","Noto Sans SC",sans-serif;
  --font-body:"PingFang SC","Microsoft YaHei","Noto Sans SC",sans-serif;
  --font-mono:"JetBrains Mono","IBM Plex Mono","SFMono-Regular",ui-monospace,monospace;

  --shell:1240px;
  --gutter:clamp(20px,4vw,40px);
  --header-h:78px;
  --ease:150ms ease;
}

/* ---------- 02 reset ---------- */
*,
*::before,
*::after{box-sizing:border-box}

html{-webkit-text-size-adjust:100%;text-size-adjust:100%}

body,
h1,h2,h3,h4,h5,h6,
p,figure,blockquote,dl,dd{margin:0}

ul[class],
ol[class]{margin:0;padding:0;list-style:none}

img,
svg{display:block;max-width:100%}

a{color:inherit;text-decoration:none}

button{font:inherit;color:inherit;background:none;border:0;padding:0;cursor:pointer}

body{
  background:var(--navy-900);
  color:var(--ivory);
  font-family:var(--font-body);
  font-size:16px;
  line-height:1.75;
  letter-spacing:.01em;
  min-height:100vh;
  -webkit-font-smoothing:antialiased;
}

::selection{background:var(--amber);color:var(--navy-900)}

hr{border:0}

/* ---------- 03 typography ---------- */
h1,h2,h3,h4,h5,h6{
  font-family:var(--font-heading);
  font-weight:500;
  line-height:1.2;
  letter-spacing:.04em;
  color:var(--paper);
  text-wrap:balance;
}

h1{font-size:clamp(32px,4.4vw,56px);line-height:1.14}
h2{font-size:clamp(26px,3vw,36px);line-height:1.22}
h3{font-size:clamp(19px,2vw,24px);line-height:1.32}
h4{font-size:17px;line-height:1.4;letter-spacing:.06em}

p{max-width:68ch}

strong{color:var(--amber-light);font-weight:600}

code,kbd,samp,.mono{font-family:var(--font-mono);font-size:.92em}

#main-content{display:block;scroll-margin-top:calc(var(--header-h) + 12px)}

/* ---------- 04 shared components ---------- */
.shell{
  width:100%;
  max-width:var(--shell);
  margin-inline:auto;
  padding-inline:var(--gutter);
}

.section{padding-block:clamp(56px,8vw,112px)}

.eyebrow{
  display:inline-block;
  font-family:var(--font-mono);
  font-size:11px;
  line-height:1.6;
  letter-spacing:.24em;
  text-transform:uppercase;
  color:var(--amber);
}

.rule{
  height:1px;
  width:100%;
  background:var(--navy-600);
  border:0;
  margin:0;
}

.panel{
  background:var(--navy-800);
  border:1px solid var(--navy-600);
  padding:clamp(20px,3vw,36px);
  transition:border-color var(--ease),background-color var(--ease);
}
.panel:hover{border-color:var(--amber)}
.panel--deep{background:var(--teal-deep);border-color:#1B504D}
.panel--deep:hover{border-color:var(--celadon)}
.panel--wine{background:var(--wine);border-color:#6A3346}
.panel--indigo{background:var(--indigo);border-color:#3B2E6B}
.panel--paper{background:var(--paper);color:var(--ink);border-color:var(--line)}
.panel--paper h1,.panel--paper h2,.panel--paper h3,.panel--paper h4{color:var(--ink)}
.panel--paper p{color:var(--slate)}

.btn{
  display:inline-flex;
  align-items:center;
  gap:10px;
  padding:13px 22px;
  border:1px solid var(--amber);
  background:transparent;
  color:var(--amber-light);
  font-family:var(--font-body);
  font-size:14px;
  letter-spacing:.06em;
  line-height:1.4;
  transition:background-color var(--ease),color var(--ease),border-color var(--ease);
}
.btn:hover{background:var(--amber);color:var(--navy-900);border-color:var(--amber)}
.btn--solid{background:var(--amber);color:var(--navy-900);border-color:var(--amber)}
.btn--solid:hover{background:var(--amber-light);border-color:var(--amber-light)}
.btn--ghost{border-color:var(--navy-600);color:var(--ivory)}
.btn--ghost:hover{border-color:var(--amber);background:transparent;color:var(--amber-light)}

.breadcrumb{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:8px;
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.08em;
  color:var(--on-dark-faint);
}
.breadcrumb a{
  color:var(--on-dark);
  border-bottom:1px solid var(--navy-600);
  padding-bottom:1px;
  transition:color var(--ease),border-color var(--ease);
}
.breadcrumb a:hover{color:var(--amber-light);border-bottom-color:var(--amber)}
.breadcrumb [aria-current="page"]{color:var(--celadon)}
.breadcrumb__sep{color:var(--navy-600);font-size:10px}

.tag{
  display:inline-flex;
  align-items:center;
  gap:6px;
  padding:4px 9px;
  border:1px solid var(--navy-600);
  font-family:var(--font-mono);
  font-size:10.5px;
  line-height:1.6;
  letter-spacing:.12em;
  color:var(--ivory);
  white-space:nowrap;
}
.tag--live{color:var(--celadon);border-color:var(--celadon-dark)}
.tag--warm{color:var(--amber);border-color:#7A5A22}

.figure{margin:0;width:100%}
.figure__media{
  position:relative;
  overflow:hidden;
  width:100%;
  aspect-ratio:16/10;
  background:var(--navy-800);
  border:1px solid var(--navy-600);
}
.figure__media > img,
.figure__media > svg{
  width:100%;
  height:100%;
  object-fit:cover;
}
.figure__media--wide{aspect-ratio:21/9}
.figure__media--tall{aspect-ratio:4/5}
.figure__media--square{aspect-ratio:1/1}
.figure figcaption{
  margin-top:10px;
  font-family:var(--font-mono);
  font-size:11.5px;
  line-height:1.7;
  letter-spacing:.04em;
  color:var(--on-dark-faint);
}

/* reveal protocol (page stage may add data-reveal) */
[data-reveal]{transition:opacity .5s ease,transform .5s ease}
html[data-motion="on"] [data-reveal]:not(.is-revealed){
  opacity:0;
  transform:translateY(14px);
}

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

.skip-link{
  position:fixed;
  top:12px;
  left:12px;
  z-index:400;
  padding:10px 18px;
  background:var(--amber);
  color:var(--navy-900);
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.12em;
  transform:translateY(-180%);
  transition:transform 180ms ease;
}
.skip-link:focus,
.skip-link:focus-visible{
  transform:translateY(0);
  outline:2px solid var(--paper);
  outline-offset:3px;
}

/* ---------- 05 header ---------- */
.site-header{
  position:sticky;
  top:0;
  z-index:80;
  background:rgba(10,26,42,.72);
  -webkit-backdrop-filter:blur(8px);
  backdrop-filter:blur(8px);
  border-bottom:1px solid transparent;
  transition:background-color 200ms ease,border-color 200ms ease,box-shadow 200ms ease;
}
.site-header[data-scrolled="true"]{
  background:var(--navy-800);
  border-bottom-color:var(--navy-600);
  box-shadow:0 1px 0 rgba(0,0,0,.35);
}

.header-frame{
  position:relative;
  width:100%;
  max-width:var(--shell);
  margin-inline:auto;
  padding-inline:var(--gutter);
  min-height:var(--header-h);
  display:grid;
  grid-template-columns:auto 1fr auto;
  align-items:center;
  gap:clamp(14px,2vw,36px);
}

.brand{
  display:inline-flex;
  align-items:center;
  gap:12px;
  padding:8px 0;
  min-height:44px;
  flex:none;
}
.brand__mark{
  position:relative;
  flex:none;
  width:26px;
  height:26px;
  border:1px solid var(--amber);
}
.brand__mark::before{
  content:"";
  position:absolute;
  top:6px;
  right:6px;
  width:7px;
  height:7px;
  background:var(--amber);
  transition:background-color var(--ease);
}
.brand__mark::after{
  content:"";
  position:absolute;
  left:6px;
  bottom:6px;
  width:12px;
  height:1px;
  background:var(--celadon);
}
.brand:hover .brand__mark::before{background:var(--amber-light)}
.brand__text{display:flex;flex-direction:column;gap:3px}
.brand__name{
  font-family:var(--font-heading);
  font-size:17px;
  font-weight:500;
  letter-spacing:.16em;
  line-height:1.2;
  color:var(--paper);
}
.brand__meta{
  font-family:var(--font-mono);
  font-size:9.5px;
  line-height:1.4;
  letter-spacing:.14em;
  text-transform:uppercase;
  color:var(--on-dark-faint);
}

.primary-nav{display:flex;justify-content:center}
.primary-nav__list{
  display:flex;
  align-items:stretch;
  gap:2px;
  flex-wrap:nowrap;
}
.nav-link{
  position:relative;
  display:flex;
  align-items:baseline;
  gap:7px;
  padding:10px 12px;
  font-size:13.5px;
  line-height:1.5;
  letter-spacing:.04em;
  color:var(--on-dark);
  white-space:nowrap;
  transition:color var(--ease);
}
.nav-link::after{
  content:"";
  position:absolute;
  left:12px;
  right:12px;
  bottom:4px;
  height:1px;
  background:var(--amber);
  transform:scaleX(0);
  transform-origin:left center;
  transition:transform 160ms ease;
}
.nav-link:hover{color:var(--paper)}
.nav-link:hover::after{transform:scaleX(1)}
.nav-link[aria-current="page"]{color:var(--amber-light)}
.nav-link[aria-current="page"]::after{transform:scaleX(1)}
.nav-link__index{
  font-family:var(--font-mono);
  font-size:9.5px;
  line-height:1;
  letter-spacing:0;
  color:var(--amber);
  opacity:.7;
  transform:translateY(-4px);
}
.nav-link[aria-current="page"] .nav-link__index{opacity:1}

.header-tools{
  display:flex;
  align-items:center;
  gap:8px;
  justify-content:flex-end;
}
.tool-chip{
  display:inline-flex;
  align-items:center;
  gap:7px;
  padding:8px 12px;
  border:1px solid var(--navy-600);
  font-family:var(--font-body);
  font-size:12.5px;
  line-height:1.4;
  letter-spacing:.06em;
  color:var(--ivory);
  white-space:nowrap;
  transition:border-color var(--ease),color var(--ease),background-color var(--ease);
}
.tool-chip:hover{
  border-color:var(--amber);
  color:var(--amber-light);
  background:rgba(226,169,75,.08);
}
.tool-chip__dot{
  flex:none;
  width:6px;
  height:6px;
  background:var(--celadon);
  transition:background-color var(--ease);
}
.tool-chip--amber .tool-chip__dot{background:var(--amber)}
.tool-chip:hover .tool-chip__dot{background:var(--amber-light)}

.nav-toggle{
  display:none;
  align-items:center;
  gap:10px;
  padding:10px 13px;
  border:1px solid var(--navy-600);
  font-family:var(--font-mono);
  font-size:11px;
  line-height:1.4;
  letter-spacing:.16em;
  color:var(--ivory);
  transition:border-color var(--ease),color var(--ease);
}
.nav-toggle:hover{border-color:var(--amber);color:var(--amber-light)}
.nav-toggle__bars{
  position:relative;
  display:block;
  width:16px;
  height:10px;
  flex:none;
}
.nav-toggle__bars::before,
.nav-toggle__bars::after{
  content:"";
  position:absolute;
  left:0;
  right:0;
  height:1px;
  background:var(--amber);
  transition:transform 180ms ease,top 180ms ease;
}
.nav-toggle__bars::before{top:1px}
.nav-toggle__bars::after{top:8px}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::before{top:5px;transform:rotate(45deg)}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::after{top:5px;transform:rotate(-45deg)}
.nav-toggle__label{display:inline-block}

.scroll-meter{
  position:absolute;
  left:0;
  right:0;
  bottom:-1px;
  height:2px;
  background:transparent;
  pointer-events:none;
  z-index:2;
}
.scroll-meter__bar{
  display:block;
  height:100%;
  width:0;
  background:var(--amber);
  transition:width 120ms linear;
}

/* ---------- 06 footer ---------- */
.site-footer{
  position:relative;
  background:var(--navy-900);
  color:var(--ivory);
  border-top:1px solid var(--navy-600);
}

.footer-band{
  display:flex;
  align-items:stretch;
  height:6px;
  background:var(--navy-800);
}
.footer-band__seg{display:block;height:100%}
.footer-band__seg--amber{width:132px;background:var(--amber)}
.footer-band__seg--celadon{width:64px;background:var(--celadon)}
.footer-band__seg--wine{width:96px;background:var(--wine)}

.footer-frame{
  max-width:var(--shell);
  margin-inline:auto;
  padding:clamp(44px,6vw,80px) var(--gutter) clamp(36px,5vw,56px);
  display:grid;
  grid-template-columns:minmax(0,.95fr) minmax(0,1.25fr);
  gap:clamp(32px,5vw,80px);
}

.footer-lead{min-width:0}
.brand--footer{padding:0;min-height:0}
.footer-intro{
  margin-top:22px;
  max-width:38ch;
  font-size:14.5px;
  line-height:1.85;
  color:var(--on-dark);
}
.footer-contact{
  margin-top:26px;
  padding-top:16px;
  border-top:1px solid var(--navy-600);
}
.footer-contact__row{
  display:grid;
  grid-template-columns:78px minmax(0,1fr);
  gap:12px;
  padding:7px 0;
  align-items:baseline;
}
.footer-contact dt{
  font-family:var(--font-mono);
  font-size:10px;
  line-height:1.8;
  letter-spacing:.16em;
  color:var(--celadon);
  white-space:nowrap;
}
.footer-contact dd{
  font-family:var(--font-mono);
  font-size:12.5px;
  line-height:1.7;
  color:var(--paper);
  word-break:break-word;
}
.footer-note{
  margin-top:18px;
  max-width:42ch;
  padding-left:12px;
  border-left:2px solid var(--navy-600);
  font-size:12px;
  line-height:1.8;
  color:var(--on-dark-faint);
}

.footer-nav{
  display:grid;
  grid-template-columns:repeat(3,minmax(0,1fr));
  gap:clamp(20px,3vw,40px);
  align-content:start;
  min-width:0;
}
.footer-col{min-width:0}
.footer-col__title{
  margin:0 0 14px;
  padding-bottom:11px;
  border-bottom:1px solid var(--navy-600);
  font-family:var(--font-mono);
  font-size:10.5px;
  font-weight:500;
  line-height:1.6;
  letter-spacing:.2em;
  color:var(--amber);
}
.footer-col li + li{margin-top:1px}
.footer-col a{
  position:relative;
  display:inline-block;
  padding:7px 0;
  font-size:14px;
  line-height:1.6;
  color:var(--on-dark);
  transition:color var(--ease);
}
.footer-col a::after{
  content:"";
  position:absolute;
  left:0;
  bottom:4px;
  width:100%;
  height:1px;
  background:var(--amber);
  transform:scaleX(0);
  transform-origin:left center;
  transition:transform 160ms ease;
}
.footer-col a:hover{color:var(--amber-light)}
.footer-col a:hover::after{transform:scaleX(1)}

.footer-base{
  border-top:1px solid var(--navy-600);
  background:var(--navy-800);
}
.footer-base__inner{
  max-width:var(--shell);
  margin-inline:auto;
  padding:18px var(--gutter);
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:12px 28px;
  font-size:12px;
  line-height:1.7;
  color:var(--on-dark-dim);
}
.footer-copy{max-width:none;font-family:var(--font-mono);font-size:11.5px;letter-spacing:.06em}
.footer-legal-links{
  display:flex;
  flex-wrap:wrap;
  gap:6px 20px;
}
.footer-legal-links a{
  color:var(--on-dark);
  padding-bottom:2px;
  border-bottom:1px solid transparent;
  transition:color var(--ease),border-color var(--ease);
}
.footer-legal-links a:hover{color:var(--amber-light);border-bottom-color:var(--amber)}
.footer-icp{
  max-width:none;
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.06em;
  color:var(--on-dark-faint);
}

/* ---------- 07 responsive ---------- */
@media (max-width:1080px){
  :root{--header-h:72px}
  .brand__meta{display:none}
  .nav-link{padding:10px 9px;font-size:12.5px}
  .nav-link__index{display:none}
  .tool-chip{padding:7px 10px;font-size:11.5px}
}

@media (max-width:860px){
  :root{--header-h:64px}

  .header-frame{grid-template-columns:auto 1fr auto;gap:12px}

  .primary-nav{
    position:absolute;
    top:100%;
    left:0;
    right:0;
    display:block;
    background:var(--navy-800);
    border-top:1px solid var(--navy-600);
    border-bottom:1px solid var(--navy-600);
    max-height:0;
    overflow:hidden;
    visibility:hidden;
    transition:max-height 220ms ease;
  }
  .primary-nav[data-open="true"]{
    max-height:80vh;
    overflow-y:auto;
    visibility:visible;
  }
  .primary-nav__list{
    display:block;
    padding:6px var(--gutter) 14px;
  }
  .nav-link{
    display:flex;
    align-items:baseline;
    gap:12px;
    padding:14px 2px;
    font-size:15px;
    color:var(--ivory);
    border-bottom:1px solid var(--navy-600);
  }
  .nav-link::after{display:none}
  .nav-link__index{
    display:inline;
    font-size:11px;
    opacity:.8;
    transform:translateY(-2px);
  }
  .nav-link[aria-current="page"]{color:var(--amber-light)}
  .nav-toggle{display:inline-flex;justify-self:end}
  .header-tools{justify-content:flex-end}
  .site-header[data-nav-open="true"]{
    background:var(--navy-800);
    border-bottom-color:var(--navy-600);
  }

  .footer-frame{
    grid-template-columns:minmax(0,1fr);
    gap:40px;
  }
  .footer-base__inner{justify-content:flex-start}
}

@media (max-width:720px){
  .header-frame{grid-template-columns:minmax(0,1fr) auto}
  .header-tools{display:none}
  .footer-nav{grid-template-columns:repeat(2,minmax(0,1fr));gap:26px 24px}
  .footer-contact__row{grid-template-columns:72px minmax(0,1fr);gap:10px}
  .footer-band__seg--amber{width:88px}
  .footer-band__seg--celadon{width:48px}
}

@media (max-width:480px){
  .brand__name{font-size:15.5px;letter-spacing:.12em}
  .nav-toggle{padding:9px 11px;font-size:10px}
  .footer-nav{grid-template-columns:minmax(0,1fr)}
  .footer-legal-links{gap:6px 16px}
}

/* ---------- 08 reduced motion ---------- */
@media (prefers-reduced-motion:reduce){
  *,
  *::before,
  *::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
    scroll-behavior:auto !important;
  }
  .site-header,
  .primary-nav,
  .scroll-meter__bar{transition:none}
  html[data-motion="on"] [data-reveal]:not(.is-revealed){
    opacity:1;
    transform:none;
  }
}