/* ===== Reset & Variables ===== */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  font-family:'Noto Sans SC','PingFang SC',sans-serif;
  font-size:1rem;line-height:1.7;color:#F5F1E8;
  background:linear-gradient(160deg,#0A1A3A 0%,#0F2249 55%,#0A1A3A 100%);
  min-height:100vh;
  overflow-x:hidden;
}
img{max-width:100%;display:block}
a{color:inherit;text-decoration:none}
ul{list-style:none}
button{font:inherit;background:none;border:none;cursor:pointer}
:focus-visible{outline:2px solid #D4A72C;outline-offset:3px;border-radius:2px}
::selection{background:#D4A72C;color:#0A1A3A}

/* ===== Variables ===== */
:root{
  --navy-900:#0A1A3A;
  --navy-700:#12294F;
  --gold-500:#D4A72C;
  --red-500:#E63946;
  --blue-300:#5A7BA6;
  --off-white:#F5F1E8;
  --muted:#8496B2;
  --green-400:#2A9D8F;
  --dark-charcoal:#101418;
  --white:#FFFFFF;
  --title-font:'Alibaba PuHuiTi 3.0','Noto Sans SC',sans-serif;
  --body-font:'Noto Sans SC','PingFang SC',sans-serif;
  --mono-font:'JetBrains Mono','Roboto Mono',monospace;
  --h1-size:clamp(2.5rem,6vw,4.5rem);
  --h2-size:clamp(2rem,4vw,3rem);
  --h3-size:clamp(1.5rem,2.5vw,2rem);
  --container:1200px;
  --space-lg:clamp(3rem,6vw,5rem);
  --space-md:clamp(2rem,4vw,3rem);
  --space-sm:1.5rem;
  --header-offset:0px;
}

/* ===== Layout Helpers ===== */
.container{max-width:var(--container);margin:0 auto;padding:0 clamp(1rem,4vw,2rem)}
.site-frame{max-width:var(--container);margin:0 auto;padding:0 clamp(1rem,4vw,2rem)}
.main-content{position:relative;z-index:1}
.grid-lines{
  position:absolute;inset:0;pointer-events:none;opacity:.5;
  background-image:
    linear-gradient(rgba(90,123,166,.12) 1px,transparent 1px),
    linear-gradient(90deg,rgba(90,123,166,.12) 1px,transparent 1px);
  background-size:32px 32px;
}
.grid-lines-dark{opacity:.25;background-image:linear-gradient(rgba(90,123,166,.1) 1px,transparent 1px),linear-gradient(90deg,rgba(90,123,166,.1) 1px,transparent 1px)}

/* ===== Skip Link ===== */
.skip-link{
  position:fixed;top:-60px;left:1rem;z-index:2000;
  background:var(--gold-500);color:var(--navy-900);
  padding:.6rem 1.2rem;font-weight:700;border-radius:4px;
  transition:top .25s ease;
}
.skip-link:focus{top:.5rem}

/* ===== Header ===== */
.site-header{
  position:relative;z-index:100;
  background:linear-gradient(180deg,var(--navy-900) 0%,var(--navy-700) 100%);
  border-bottom:1px solid rgba(90,123,166,.35);
  box-shadow:0 4px 30px rgba(4,10,24,.5);
}
.header-inner{position:relative}
.header-topbar{
  display:flex;align-items:center;justify-content:space-between;
  padding:1.2rem 0 .9rem;gap:1rem;flex-wrap:wrap;
}
.brand-lockup{display:flex;align-items:baseline;gap:.5rem;line-height:1.2}
.brand-name{
  font-family:var(--title-font);font-weight:900;
  font-size:1.65rem;letter-spacing:.04em;color:var(--gold-500);
  text-shadow:0 0 24px rgba(212,167,44,.25);
}
.brand-suffix{
  font-family:var(--mono-font);font-size:.72rem;letter-spacing:.2em;
  color:var(--blue-300);text-transform:uppercase;
  border:1px solid rgba(90,123,166,.3);padding:.2rem .5rem;border-radius:2px;
}
.header-note{
  font-size:.75rem;color:var(--muted);letter-spacing:.12em;
  border-left:2px solid var(--gold-500);padding-left:.8rem;
  display:none;
}
.reading-progress{
  display:none;align-items:center;gap:.6rem;margin-left:auto;
}
.reading-progress-label{
  font-family:var(--mono-font);font-size:.6rem;color:var(--blue-300);
  letter-spacing:.2em;
}
.reading-progress-container{
  width:110px;height:3px;background:rgba(90,123,166,.25);overflow:hidden;
}
.reading-progress-bar{
  height:100%;width:0%;background:linear-gradient(90deg,var(--gold-500),var(--red-500));
  transition:width .15s ease-out;
}

/* ===== Navigation ===== */
.header-nav{
  border-top:1px solid rgba(90,123,166,.2);
  padding:.3rem 0;
  position:relative;
}
.nav-toggle{
  display:flex;align-items:center;gap:.7rem;
  color:var(--off-white);padding:.7rem .9rem;
  border:1px solid rgba(90,123,166,.4);border-radius:4px;
  width:100%;justify-content:center;margin:.4rem 0;
  background:rgba(90,123,166,.08);
}
.nav-toggle:hover,.nav-toggle[aria-expanded="true"]{
  border-color:var(--gold-500);background:rgba(212,167,44,.08);
}
.nav-toggle-line{display:block;width:18px;height:2px;background:currentColor;margin:3px 0;transition:transform .25s,opacity .25s}
.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(1){transform:translateY(5px) rotate(45deg)}
.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(2){opacity:0}
.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(3){transform:translateY(-5px) rotate(-45deg)}
.nav-toggle-text{font-size:.8rem;letter-spacing:.15em;font-family:var(--mono-font)}
.nav-list{
  display:none;flex-direction:column;gap:0;
  padding:0 0 .5rem;
}
[data-nav][data-open="true"]{display:flex}
.nav-link{
  display:flex;align-items:center;justify-content:space-between;
  padding:.85rem 1rem;color:var(--off-white);
  font-size:.95rem;border-left:2px solid transparent;
  transition:border-color .2s,color .2s,background .2s;
}
.nav-link em{
  font-family:var(--mono-font);font-style:normal;font-size:.65rem;
  color:var(--muted);letter-spacing:.1em;
}
.nav-link:hover{
  color:var(--gold-500);border-left-color:var(--gold-500);
  background:rgba(212,167,44,.06);
}
.nav-link[aria-current="page"]{
  color:var(--gold-500);border-left-color:var(--red-500);
  background:rgba(212,167,44,.1);
}
.nav-link[aria-current="page"]::before{
  content:"●";font-size:.55rem;color:var(--red-500);margin-right:.5rem;
}

/* ===== Footer ===== */
.site-footer{
  position:relative;z-index:10;
  background:linear-gradient(180deg,#0E1419 0%,var(--dark-charcoal) 100%);
  border-top:4px solid var(--gold-500);
  margin-top:var(--space-lg);
  color:var(--off-white);
}
.footer-grid{
  display:grid;grid-template-columns:1fr;
  gap:2.5rem;padding-top:3.5rem;padding-bottom:2.5rem;
  position:relative;z-index:1;
}
.footer-brand-name{
  font-family:var(--title-font);font-weight:900;font-size:1.8rem;
  color:var(--gold-500);letter-spacing:.05em;
}
.footer-brand-suffix{
  font-family:var(--mono-font);font-size:.7rem;color:var(--blue-300);
  letter-spacing:.25em;text-transform:uppercase;margin:.2rem 0 1rem;
}
.footer-about{
  color:var(--muted);font-size:.9rem;max-width:300px;line-height:1.8;
}
.footer-column h2{
  font-size:.85rem;letter-spacing:.18em;color:var(--gold-500);
  font-weight:700;margin-bottom:1.2rem;
  display:flex;align-items:center;gap:.6rem;
}
.footer-heading span{
  font-family:var(--mono-font);font-size:.65rem;color:var(--blue-300);
  border:1px solid rgba(90,123,166,.4);padding:2px 6px;border-radius:2px;
}
.footer-list li{margin-bottom:.7rem}
.footer-link{
  color:var(--off-white);font-size:.88rem;opacity:.85;
  transition:color .2s,padding-left .2s,opacity .2s;
  border-bottom:1px solid transparent;
}
.footer-link:hover{opacity:1;color:var(--red-500);padding-left:.4rem}
.footer-meta{
  border-top:1px solid rgba(90,123,166,.15);
  padding:1.5rem 0;
}
.footer-meta-inner{
  display:flex;flex-direction:column;gap:.8rem;
  justify-content:space-between;align-items:center;text-align:center;
}
.footer-contact{
  font-family:var(--mono-font);font-size:.7rem;color:var(--muted);
  letter-spacing:.06em;
}
.footer-legal{display:flex;gap:1.5rem;flex-wrap:wrap;justify-content:center;align-items:center}
.footer-icp{
  font-size:.72rem;color:var(--blue-300);
  border:1px solid rgba(90,123,166,.3);padding:.2rem .6rem;border-radius:2px;
}
.footer-copyright{font-size:.72rem;color:var(--muted)}

/* ===== Shared Buttons ===== */
.btn-gold{
  display:inline-flex;align-items:center;gap:.6rem;
  background:var(--gold-500);color:var(--navy-900);
  font-weight:700;font-size:.95rem;
  padding:.85rem 1.8rem;border-radius:4px;
  border:1px solid transparent;
  transition:transform .2s,box-shadow .2s,background .2s;
  cursor:pointer;
}
.btn-gold:hover{
  background:#E6BC3A;transform:translateY(-2px);
  box-shadow:0 8px 24px rgba(212,167,44,.35);
}
.btn-outline{
  display:inline-flex;align-items:center;gap:.6rem;
  background:transparent;color:var(--blue-300);
  border:1px solid var(--blue-300);
  font-weight:600;font-size:.9rem;
  padding:.8rem 1.6rem;border-radius:4px;
  transition:background .2s,color .2s,border-color .2s;
}
.btn-outline:hover{background:rgba(90,123,166,.1);color:var(--off-white);border-color:var(--off-white)}

/* ===== Section Number / Anchor ===== */
.section-number{
  font-family:var(--mono-font);font-weight:800;
  font-size:clamp(2.2rem,5vw,4rem);
  color:var(--gold-500);line-height:1;
  display:flex;align-items:center;gap:1rem;
  margin-bottom:1rem;
}
.section-number::after{
  content:"";flex:1;height:1px;
  background:linear-gradient(90deg,var(--gold-500),rgba(212,167,44,0));
}
.section-number small{
  font-size:.7rem;color:var(--blue-300);letter-spacing:.2em;
  align-self:flex-end;
}
/* ===== Cards ===== */
.card{
  background:linear-gradient(145deg,var(--navy-700),var(--navy-900));
  border-left:3px solid var(--gold-500);
  border-radius:6px;
  padding:clamp(1.2rem,3vw,2rem);
  transition:transform .25s,border-color .25s,box-shadow .25s;
}
.card:hover{
  transform:translateY(-4px);
  border-color:var(--red-500);
  box-shadow:0 12px 32px rgba(4,10,24,.45);
}
/* ===== Status Badge ===== */
.status-badge{
  display:inline-flex;align-items:center;gap:.5rem;
  background:rgba(230,57,70,.15);color:var(--red-500);
  font-size:.75rem;font-weight:600;letter-spacing:.1em;
  padding:.3rem .8rem;border-radius:20px;
  border:1px solid rgba(230,57,70,.35);
}
.status-badge::before{
  content:"";
  width:6px;height:6px;border-radius:50%;
  background:var(--red-500);
  animation:pulse 2s infinite;
}
@keyframes pulse{0%,100%{opacity:1;box-shadow:0 0 0 0 rgba(230,57,70,.3)}50%{opacity:.6;box-shadow:0 0 0 4px rgba(230,57,70,0)}}
/* ===== Tech Tag ===== */
.tech-tag{
  display:inline-block;
  font-family:var(--mono-font);font-size:.65rem;
  letter-spacing:.15em;color:var(--blue-300);
  border:1px solid rgba(90,123,166,.3);
  background:rgba(90,123,166,.07);
  padding:.25rem .6rem;border-radius:3px;
  margin-right:.5rem;margin-bottom:.4rem;
}
.tech-tag--gold{border-color:rgba(212,167,44,.4);color:var(--gold-500)}
.tech-tag--red{border-color:rgba(230,57,70,.4);color:var(--red-500)}
/* ===== Hero / Diagonal ===== */
.hero-panel{
  position:relative;
  padding:clamp(2rem,5vw,4rem) 0;
}
.diagonal-tile{
  position:relative;
  background:var(--navy-700);
  clip-path:polygon(0 0,100% 0,100% calc(100% - 36px),calc(100% - 36px) 100%,0 100%);
  padding:clamp(2rem,6vw,5rem) clamp(1.2rem,5vw,4rem) clamp(3rem,7vw,6rem);
}
.diagonal-tile::before{
  content:"";position:absolute;top:0;right:0;
  width:110px;height:110px;
  background:linear-gradient(135deg,transparent 45%,var(--gold-500) 46%,var(--gold-500) 54%,transparent 55%);
  opacity:.7;
}
.edition-label{
  writing-mode:vertical-rl;text-orientation:mixed;
  font-family:var(--mono-font);font-size:.65rem;letter-spacing:.3em;
  color:var(--blue-300);text-transform:uppercase;
  position:absolute;right:-.8rem;top:2rem;
}
/* ===== Back-to-top ===== */
.back-to-top{
  position:fixed;bottom:1.5rem;right:1.5rem;z-index:200;
  width:48px;height:48px;border-radius:6px;
  background:var(--navy-700);border:1px solid var(--gold-500);
  color:var(--gold-500);font-size:1.3rem;cursor:pointer;
  display:flex;align-items:center;justify-content:center;
  opacity:0;visibility:hidden;transform:translateY(16px);
  transition:opacity .25s,visibility .25s,transform .25s,background .2s;
}
.back-to-top.show{opacity:1;visibility:visible;transform:translateY(0)}
.back-to-top:hover{background:var(--gold-500);color:var(--navy-900)}
.back-to-top::before{content:"↑";font-family:var(--mono-font);font-weight:700}

/* ===== Scroll Reveal ===== */
[data-reveal]{
  opacity:0;transform:translateY(24px);
  transition:opacity .6s ease,transform .6s ease;
  will-change:opacity,transform;
}
[data-reveal].is-revealed{
  opacity:1;transform:translateY(0);
}

/* ===== Responsive ===== */
@media (min-width:640px){
  .footer-grid{grid-template-columns:1fr 1fr;gap:3rem}
  .footer-meta-inner{flex-direction:row;text-align:left}
  .header-note{display:block}
  .reading-progress{display:flex}
}
@media (min-width:768px){
  .grid-lines{background-size:40px 40px}
  .nav-toggle{display:none}
  .header-nav{border-top:1px solid rgba(90,123,166,.2)}
  .nav-list{display:flex;flex-direction:row;gap:0;padding:0}
  .nav-link{flex:1;justify-content:center;gap:.4rem;border-left:none;border-bottom:2px solid transparent;padding:1rem .4rem}
  .nav-link em{display:inline;font-size:.6rem}
  .nav-link:hover{border-left:none;border-bottom-color:var(--gold-500);background:rgba(212,167,44,.04)}
  .nav-link[aria-current="page"]{border-left:none;border-bottom-color:var(--red-500);background:rgba(212,167,44,.06)}
  .nav-link[aria-current="page"]::before{display:none}
  .header-topbar{padding:1.6rem 0 1rem}
  .brand-name{font-size:2rem}
}
@media (min-width:1024px){
  .footer-grid{grid-template-columns:1.4fr 1fr 1fr 1fr;gap:4rem;padding-top:4.5rem}
  .footer-meta-inner{flex-direction:row;justify-content:space-between}
}

/* ===== Reduced Motion ===== */
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    animation-duration:0.01ms !important;
    animation-iteration-count:1 !important;
    transition-duration:0.01ms !important;
  }
  [data-reveal]{opacity:1;transform:none}
  .back-to-top{transition:none}
}
/* ===== Aria-disabled nav item ===== */
a[aria-disabled="true"]{pointer-events:none;opacity:.4}