/* =========================================================================
   景安宮 Digital Heritage Museum — main.css
   Design system · Navigation · Layout · Footer · Day/Night theme
   Apple × 故宮 × Google Arts & Culture
   ========================================================================= */

/* ---------- Design Tokens ---------- */
:root{
  /* Night (default) — 廟宇夜色 */
  --bg:#0b0a08;
  --bg-2:#121009;
  --bg-3:#1a160e;
  --surface:rgba(28,23,15,.72);
  --ink:#f3ead6;              /* warm ivory text */
  --ink-soft:#c9bda3;
  --muted:#8c806a;
  --line:rgba(201,162,75,.16);
  --line-strong:rgba(201,162,75,.34);

  /* Sacred palette */
  --gold:#c9a24b;
  --gold-2:#e8cd8a;
  --gold-3:#f6e6bd;
  --gold-deep:#9a7529;
  --cinnabar:#b7331d;
  --cinnabar-2:#d5502f;
  --jade:#2f6b52;
  --incense:rgba(245,238,214,.7);

  --gold-glow:0 0 40px rgba(201,162,75,.35);
  --shadow-deep:0 30px 80px -30px rgba(0,0,0,.85);

  --maxw:1240px;
  --gut:clamp(20px,4vw,48px);
  --nav-h:74px;

  --ease:cubic-bezier(.22,.61,.36,1);
  --ease-out:cubic-bezier(.16,1,.3,1);
  --serif:"Noto Serif TC",serif;
  --sans:"Noto Sans TC",-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;
  --latin:"Cormorant Garamond",var(--serif);
}

/* Day — 廟埕天光 */
[data-theme="day"]{
  --bg:#f4eee1;
  --bg-2:#efe6d3;
  --bg-3:#e7dbc2;
  --surface:rgba(255,252,245,.78);
  --ink:#2a2115;
  --ink-soft:#5c4f38;
  --muted:#8a7d63;
  --line:rgba(154,117,41,.20);
  --line-strong:rgba(154,117,41,.4);
  --gold:#9a7529;
  --gold-2:#c9a24b;
  --incense:rgba(120,100,60,.5);
  --shadow-deep:0 30px 80px -34px rgba(74,56,20,.4);
}

/* ---------- Reset ---------- */
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:auto;-webkit-text-size-adjust:100%}
body{
  font-family:var(--sans);
  background:var(--bg);
  color:var(--ink);
  line-height:1.85;
  letter-spacing:.01em;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
  overflow-x:hidden;
  transition:background .9s var(--ease),color .9s var(--ease);
}
h1,h2,h3,h4,.serif{font-family:var(--serif);font-weight:900;line-height:1.28;letter-spacing:.02em}
a{color:inherit;text-decoration:none}
img{max-width:100%;display:block}
button{font-family:inherit;cursor:pointer;border:none;background:none;color:inherit}
::selection{background:rgba(201,162,75,.32);color:var(--gold-3)}

/* ---------- Layout helpers ---------- */
.wrap{max-width:var(--maxw);margin:0 auto;padding-left:var(--gut);padding-right:var(--gut)}
.section{position:relative;padding:clamp(88px,12vw,160px) 0}
.eyebrow{
  display:inline-flex;align-items:center;gap:.7em;
  font-family:var(--latin);font-weight:600;font-size:.82rem;
  letter-spacing:.42em;text-transform:uppercase;color:var(--gold);
}
.eyebrow::before{content:"";width:34px;height:1px;background:linear-gradient(90deg,transparent,var(--gold))}
.title-h2{font-size:clamp(2rem,5vw,3.4rem);color:var(--ink)}
.gold-line{width:64px;height:2px;margin:26px 0;background:linear-gradient(90deg,var(--gold),transparent);border-radius:2px}
.lead{color:var(--ink-soft);max-width:60ch;font-size:clamp(1rem,1.4vw,1.14rem)}
.gold-text{
  background:linear-gradient(100deg,var(--gold-deep),var(--gold-2) 40%,var(--gold-3) 55%,var(--gold) 75%);
  -webkit-background-clip:text;background-clip:text;color:transparent;
}

/* ---------- Buttons ---------- */
.btn{
  display:inline-flex;align-items:center;gap:.6em;
  padding:14px 30px;border-radius:100px;font-weight:700;font-size:.95rem;
  letter-spacing:.06em;transition:transform .5s var(--ease-out),box-shadow .5s,background .4s,color .4s;
  will-change:transform;
}
.btn .arw{transition:transform .5s var(--ease-out)}
.btn:hover .arw{transform:translateX(5px)}
.btn-gold{
  background:linear-gradient(120deg,var(--gold-deep),var(--gold) 55%,var(--gold-2));
  color:#20180a;box-shadow:0 10px 30px -10px rgba(201,162,75,.6);
}
.btn-gold:hover{transform:translateY(-3px);box-shadow:0 18px 44px -12px rgba(201,162,75,.75)}
.btn-ghost{border:1px solid var(--line-strong);color:var(--ink);backdrop-filter:blur(6px)}
.btn-ghost:hover{border-color:var(--gold);color:var(--gold-2);transform:translateY(-3px)}

/* ---------- Navigation ---------- */
.nav{
  position:fixed;top:0;left:0;right:0;z-index:100;height:var(--nav-h);
  display:flex;align-items:center;gap:20px;
  padding:0 var(--gut);
  transition:background .5s var(--ease),backdrop-filter .5s,border-color .5s;
  border-bottom:1px solid transparent;
}
.nav.scrolled{
  background:color-mix(in srgb,var(--bg) 82%,transparent);
  backdrop-filter:blur(16px) saturate(1.3);
  border-bottom-color:var(--line);
}
.nav-brand{display:flex;align-items:center;gap:12px;margin-right:auto;flex:none}
.nav-seal{
  width:40px;height:40px;border-radius:9px;flex:none;
  display:grid;place-items:center;font-family:var(--serif);font-weight:900;
  color:var(--gold-3);font-size:.66rem;line-height:1.05;text-align:center;
  background:radial-gradient(circle at 30% 25%,var(--cinnabar-2),var(--cinnabar) 65%,#7c2012);
  box-shadow:inset 0 0 0 1px rgba(255,220,160,.35),0 6px 18px -8px rgba(0,0,0,.7);
  letter-spacing:-.02em;
}
.nav-name{display:flex;flex-direction:column;line-height:1.05}
.nav-name b{font-family:var(--serif);font-size:1.14rem;font-weight:900;color:var(--ink);letter-spacing:.12em}
.nav-name span{font-family:var(--latin);font-size:.62rem;letter-spacing:.34em;color:var(--muted);text-transform:uppercase}
.nav-links{display:flex;align-items:center;gap:6px}
.nav-links a{
  position:relative;padding:9px 14px;font-size:.92rem;color:var(--ink-soft);
  border-radius:9px;transition:color .35s;
}
.nav-links a::after{
  content:"";position:absolute;left:14px;right:14px;bottom:5px;height:1.5px;
  background:linear-gradient(90deg,var(--gold),var(--gold-2));
  transform:scaleX(0);transform-origin:left;transition:transform .4s var(--ease-out);border-radius:2px;
}
.nav-links a:hover{color:var(--gold-2)}
.nav-links a:hover::after,.nav-links a[aria-current="page"]::after{transform:scaleX(1)}
.nav-tools{display:flex;align-items:center;gap:6px;flex:none}
.icon-btn{
  width:40px;height:40px;border-radius:10px;display:grid;place-items:center;
  color:var(--ink-soft);border:1px solid var(--line);transition:.35s;
}
.icon-btn:hover{color:var(--gold-2);border-color:var(--line-strong);background:rgba(201,162,75,.08)}
.icon-btn svg{width:19px;height:19px}
.icon-btn.on{color:var(--gold-2);border-color:var(--line-strong)}
.nav-burger{display:none}

/* Mobile full-screen menu */
.menu-overlay{
  position:fixed;inset:0;z-index:99;background:var(--bg-2);
  transform:translateY(-100%);transition:transform .7s var(--ease-out);
  display:flex;flex-direction:column;justify-content:center;gap:6px;padding:0 var(--gut);
  visibility:hidden;
}
.menu-overlay.open{transform:translateY(0);visibility:visible}
.menu-overlay a{
  font-family:var(--serif);font-size:clamp(1.6rem,7vw,2.4rem);font-weight:900;
  color:var(--ink);padding:10px 0;display:flex;align-items:baseline;gap:16px;
  border-bottom:1px solid var(--line);opacity:0;transform:translateY(20px);
}
.menu-overlay.open a{animation:menuIn .6s var(--ease-out) forwards}
.menu-overlay a i{font-family:var(--latin);font-size:.8rem;color:var(--gold);font-style:normal;letter-spacing:.2em}
@keyframes menuIn{to{opacity:1;transform:none}}

/* ---------- Footer ---------- */
.footer{
  position:relative;padding:clamp(70px,9vw,120px) 0 40px;
  border-top:1px solid var(--line);background:var(--bg-2);overflow:hidden;
}
.footer-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr;gap:48px}
.footer-brand .nav-name b{font-size:1.5rem}
.footer h4{font-size:.82rem;letter-spacing:.28em;color:var(--gold);text-transform:uppercase;font-family:var(--latin);margin-bottom:18px;font-weight:600}
.footer ul{list-style:none;display:flex;flex-direction:column;gap:12px}
.footer ul a{color:var(--ink-soft);font-size:.95rem;transition:color .3s}
.footer ul a:hover{color:var(--gold-2)}
.footer-note{color:var(--ink-soft);max-width:34ch;margin:18px 0 0;font-size:.94rem}
.footer-bottom{
  margin-top:56px;padding-top:26px;border-top:1px solid var(--line);
  display:flex;justify-content:space-between;gap:16px;flex-wrap:wrap;
  color:var(--muted);font-size:.82rem;letter-spacing:.03em;
}

/* ---------- Accessibility ---------- */
.skip-link{position:absolute;left:-999px;top:8px;z-index:200;background:var(--gold);color:#20180a;padding:10px 18px;border-radius:8px}
.skip-link:focus{left:12px}
:focus-visible{outline:2px solid var(--gold-2);outline-offset:3px;border-radius:4px}

@media (prefers-reduced-motion:reduce){
  *,*::before,*::after{animation-duration:.001ms!important;animation-iteration-count:1!important;transition-duration:.001ms!important}
  html{scroll-behavior:auto}
}