/* ==========================================================================
   V3新视界 · VEETHREE — Refined Minimalist (Apple-inspired)
   PHP · HTML · CSS · inline JS. Monochrome premium. Card-stack signature.
   ========================================================================== */

/* ---------- Tokens ---------- */
:root {
  --bg:        #fbfbfd;
  --bg-2:      #f5f5f7;
  --surface:   #ffffff;
  --surface-2: rgba(255,255,255,0.72);
  --surface-3: rgba(255,255,255,0.5);
  --ink:       #1d1d1f;
  --ink-2:     #6e6e73;
  --ink-3:     #86868b;
  --line:      #d2d2d7;
  --line-2:    #e8e8ed;
  --shadow:    0 1px 2px rgba(0,0,0,0.04), 0 8px 24px rgba(0,0,0,0.06);
  --shadow-lg: 0 2px 8px rgba(0,0,0,0.06), 0 24px 60px rgba(0,0,0,0.12);
  --shadow-stack: 0 30px 80px rgba(0,0,0,0.16), 0 8px 24px rgba(0,0,0,0.08);

  --maxw: 1200px;
  --gut: clamp(20px, 5vw, 64px);
  --nav-h: 68px;

  --r-xs: 10px;
  --r-sm: 14px;
  --r:    20px;
  --r-lg: 28px;
  --r-xl: 40px;
  --r-pill: 999px;

  --ff-display: "Manrope", "Noto Sans SC", sans-serif;
  --ff-body:    "Manrope", "Noto Sans SC", sans-serif;
  --ff-mono:    "Space Mono", "Manrope", monospace;

  --fs-hero: clamp(2.8rem, 8vw, 6.25rem);
  --fs-h1:   clamp(2.2rem, 5vw, 3.75rem);
  --fs-h2:   clamp(1.6rem, 3vw, 2.5rem);
  --fs-h3:   clamp(1.3rem, 2vw, 1.6rem);
  --fs-lg:   1.1875rem;
  --fs-body: 1.0625rem;
  --fs-sm:   0.9375rem;
  --fs-xs:   0.8125rem;

  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
}

[data-theme="dark"] {
  --bg:        #000000;
  --bg-2:      #0a0a0c;
  --surface:   #1c1c1e;
  --surface-2: rgba(28,28,30,0.72);
  --surface-3: rgba(58,58,60,0.4);
  --ink:       #f5f5f7;
  --ink-2:     #a1a1a6;
  --ink-3:     #6e6e73;
  --line:      #38383a;
  --line-2:    #2c2c2e;
  --shadow:    0 1px 2px rgba(0,0,0,0.4), 0 8px 24px rgba(0,0,0,0.5);
  --shadow-lg: 0 2px 8px rgba(0,0,0,0.5), 0 24px 60px rgba(0,0,0,0.6);
  --shadow-stack: 0 30px 80px rgba(0,0,0,0.7), 0 8px 24px rgba(0,0,0,0.5);
}

/* ---------- Reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  font-family: var(--ff-body);
  background: var(--bg);
  color: var(--ink);
  font-size: var(--fs-body);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
  transition: background-color .5s var(--ease), color .5s var(--ease);
}
img, svg { display: block; max-width: 100%; }
img { height: auto; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }
ul { list-style: none; padding: 0; }
::selection { background: var(--ink); color: var(--bg); }

/* ---------- Helpers ---------- */
.container { width: 100%; max-width: var(--maxw); margin-inline: auto; padding-inline: var(--gut); }
.mono { font-family: var(--ff-mono); }
.eyebrow {
  font-family: var(--ff-mono);
  font-size: var(--fs-xs);
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--ink-3);
  display: inline-flex; align-items: center; gap: 0.6em;
}
.eyebrow::before { content: ""; width: 28px; height: 1px; background: var(--line); }
.ink-2 { color: var(--ink-2); }
.ink-3 { color: var(--ink-3); }
.ico { width: 1em; height: 1em; flex: none; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; gap: 0.6em;
  padding: 0.85em 1.5em;
  border-radius: var(--r-pill);
  font-weight: 600; font-size: var(--fs-sm);
  transition: transform .25s var(--ease), background-color .25s var(--ease), color .25s var(--ease), border-color .25s var(--ease);
  will-change: transform;
}
.btn-primary { background: var(--ink); color: var(--bg); }
.btn-primary:hover { transform: translateY(-2px); }
.btn-ghost { border: 1px solid var(--line); color: var(--ink); }
.btn-ghost:hover { border-color: var(--ink); transform: translateY(-2px); }
.btn .arrow { transition: transform .3s var(--ease); }
.btn:hover .arrow { transform: translateX(4px); }

/* ---------- Nav ---------- */
.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  padding: 14px var(--gut);
  transition: background-color .4s var(--ease), border-color .4s var(--ease), padding .4s var(--ease);
  border-bottom: 1px solid transparent;
}
.nav.is-scrolled {
  background: var(--surface-2);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  backdrop-filter: saturate(180%) blur(20px);
  border-bottom-color: var(--line-2);
  padding-top: 10px; padding-bottom: 10px;
}
.nav-inner {
  max-width: var(--maxw); margin-inline: auto;
  display: flex; align-items: center; justify-content: space-between; gap: 24px;
}
.nav-brand { display: inline-flex; align-items: center; gap: 12px; }
.nav-logo { width: 34px; height: 26px; object-fit: contain; }
.nav-logo.logo-dark { display: none; }
[data-theme="dark"] .nav-logo.logo-light { display: none; }
[data-theme="dark"] .nav-logo.logo-dark { display: inline-block; }
.nav-brand-text { display: flex; flex-direction: column; line-height: 1.05; }
.nav-brand-zh { font-weight: 700; font-size: 1.02rem; letter-spacing: 0.01em; }
.nav-brand-en { font-family: var(--ff-mono); font-size: 0.6rem; letter-spacing: 0.32em; color: var(--ink-3); }
.nav-links { display: flex; align-items: center; gap: 6px; }
.nav-link {
  position: relative;
  padding: 0.5em 0.95em;
  font-size: var(--fs-sm); font-weight: 500; color: var(--ink-2);
  border-radius: var(--r-pill);
  transition: color .25s var(--ease), background-color .25s var(--ease);
}
.nav-link:hover { color: var(--ink); background: var(--surface-3); }
.nav-link.is-active { color: var(--ink); }
.nav-link.is-active::after {
  content: ""; position: absolute; left: 50%; bottom: 2px; transform: translateX(-50%);
  width: 4px; height: 4px; border-radius: 50%; background: var(--ink);
}
.nav-actions { display: flex; align-items: center; gap: 10px; }
.nav-cta {
  display: inline-flex; align-items: center;
  padding: 0.6em 1.25em; border-radius: var(--r-pill);
  background: var(--ink); color: var(--bg);
  font-size: var(--fs-sm); font-weight: 600;
  transition: transform .25s var(--ease), opacity .25s var(--ease);
}
.nav-cta:hover { transform: translateY(-2px); opacity: .92; }
.theme-toggle {
  width: 38px; height: 38px; border-radius: 50%;
  display: grid; place-items: center;
  color: var(--ink); border: 1px solid var(--line);
  transition: background-color .25s var(--ease), border-color .25s var(--ease), transform .25s var(--ease);
}
.theme-toggle:hover { background: var(--surface-3); transform: rotate(-12deg); }
.theme-toggle .ico { width: 18px; height: 18px; }
.theme-toggle .ico-moon { display: none; }
[data-theme="dark"] .theme-toggle .ico-sun { display: none; }
[data-theme="dark"] .theme-toggle .ico-moon { display: block; }
.nav-burger { display: none; width: 38px; height: 38px; border-radius: 50%; border: 1px solid var(--line); position: relative; }
.nav-burger span { position: absolute; left: 11px; right: 11px; height: 1.5px; background: var(--ink); transition: transform .3s var(--ease), opacity .3s var(--ease); }
.nav-burger span:nth-child(1) { top: 15px; }
.nav-burger span:nth-child(2) { top: 21px; }
.nav-burger.is-open span:nth-child(1) { transform: translateY(3px) rotate(45deg); }
.nav-burger.is-open span:nth-child(2) { transform: translateY(-3px) rotate(-45deg); }

/* ---------- Hero ---------- */
.hero {
  position: relative;
  padding: calc(var(--nav-h) + clamp(60px, 12vh, 140px)) 0 clamp(40px, 8vh, 90px);
  overflow: hidden;
}
.hero-bg { position: absolute; inset: 0; z-index: -1; pointer-events: none; }
.hero-bg::before {
  content: ""; position: absolute; inset: -10%;
  background:
    radial-gradient(60% 50% at 50% 0%, var(--bg-2) 0%, transparent 70%),
    radial-gradient(40% 40% at 85% 20%, var(--surface-3) 0%, transparent 60%);
}
.hero-grid {
  position: absolute; inset: 0; z-index: -1; opacity: .5;
  background-image: linear-gradient(var(--line-2) 1px, transparent 1px), linear-gradient(90deg, var(--line-2) 1px, transparent 1px);
  background-size: 64px 64px;
  -webkit-mask-image: radial-gradient(70% 60% at 50% 35%, #000 0%, transparent 75%);
  mask-image: radial-gradient(70% 60% at 50% 35%, #000 0%, transparent 75%);
}
.hero-top {
  display: flex; align-items: flex-end; justify-content: space-between; gap: 32px;
  margin-bottom: clamp(28px, 5vh, 56px);
}
.hero-title {
  font-family: var(--ff-display);
  font-weight: 800;
  font-size: var(--fs-hero);
  line-height: 0.98;
  letter-spacing: -0.03em;
  text-wrap: balance;
}
.hero-title .accent {
  position: relative; display: inline-block;
  background: linear-gradient(180deg, var(--ink) 0%, var(--ink-3) 100%);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.hero-title .accent::after {
  content: ""; position: absolute; left: 0; right: 0; bottom: 0.08em; height: 0.12em;
  background: var(--ink); opacity: .12; border-radius: 2px;
}
.hero-sub {
  max-width: 42ch; color: var(--ink-2); font-size: var(--fs-lg); line-height: 1.55;
  text-wrap: pretty;
}
.hero-meta { display: flex; gap: clamp(24px, 5vw, 56px); margin-top: 8px; }
.hero-meta-item { display: flex; flex-direction: column; gap: 2px; }
.hero-meta-num { font-family: var(--ff-mono); font-size: clamp(1.6rem, 3vw, 2.2rem); font-weight: 700; letter-spacing: -0.02em; }
.hero-meta-label { font-family: var(--ff-mono); font-size: var(--fs-xs); letter-spacing: 0.2em; text-transform: uppercase; color: var(--ink-3); }

/* ---------- Card stack ---------- */
.work { padding: clamp(40px, 7vh, 80px) 0 clamp(60px, 10vh, 120px); }
.stack-wrap { position: relative; }
.stack {
  position: relative;
  height: clamp(420px, 62vh, 560px);
  perspective: 1600px;
  perspective-origin: 50% 40%;
  touch-action: pan-y;
}
.stack-track {
  position: absolute; inset: 0;
  transform-style: preserve-3d;
  will-change: transform;
  transition: transform .4s var(--ease);
}
.stack-card {
  position: absolute; left: 50%; top: 50%;
  width: min(440px, 86vw);
  transform: translate3d(var(--tx, 0), var(--ty, 0), var(--tz, 0)) scale(var(--s, 1));
  margin-left: calc(min(440px, 86vw) / -2);
  margin-top: -210px;
  background: var(--surface);
  border: 1px solid var(--line-2);
  border-radius: var(--r-lg);
  box-shadow: var(--shadow-stack);
  padding: clamp(26px, 4vw, 40px);
  opacity: var(--o, 1);
  filter: blur(var(--b, 0px));
  will-change: transform, opacity, filter;
  transition: transform .6s var(--ease), opacity .5s var(--ease), filter .5s var(--ease), box-shadow .4s var(--ease);
  transform-origin: 50% 50%;
  pointer-events: none;
}
.stack-card.is-active { pointer-events: auto; }
.stack-card.is-active:hover { box-shadow: 0 40px 100px rgba(0,0,0,0.2), 0 12px 30px rgba(0,0,0,0.1); }

.card-head { display: flex; align-items: center; justify-content: space-between; margin-bottom: 26px; }
.card-icon {
  width: 52px; height: 52px; border-radius: var(--r-sm);
  display: grid; place-items: center;
  background: var(--bg-2); color: var(--ink);
  border: 1px solid var(--line-2);
}
.card-icon .ico { width: 24px; height: 24px; }
.card-cat {
  font-family: var(--ff-mono); font-size: 0.66rem; letter-spacing: 0.18em; text-transform: uppercase;
  color: var(--ink-3); padding: 0.4em 0.8em; border: 1px solid var(--line); border-radius: var(--r-pill);
}
.card-domain { font-family: var(--ff-mono); font-size: var(--fs-xs); letter-spacing: 0.12em; color: var(--ink-3); text-transform: uppercase; margin-bottom: 10px; word-break: break-all; }
.card-title { font-family: var(--ff-display); font-weight: 700; font-size: clamp(1.5rem, 3vw, 2rem); line-height: 1.1; letter-spacing: -0.02em; }
.card-en { font-family: var(--ff-mono); font-size: var(--fs-xs); color: var(--ink-3); margin-top: 6px; letter-spacing: 0.05em; }
.card-desc { color: var(--ink-2); font-size: var(--fs-body); line-height: 1.6; margin-top: 18px; text-wrap: pretty; }
.card-foot { display: flex; align-items: center; justify-content: space-between; margin-top: 28px; padding-top: 22px; border-top: 1px solid var(--line-2); }
.card-cta { display: inline-flex; align-items: center; gap: 0.5em; font-weight: 600; font-size: var(--fs-sm); color: var(--ink); }
.card-cta .ico { width: 18px; height: 18px; transition: transform .3s var(--ease); }
.card-cta:hover .ico { transform: translate(3px, -3px); }
.card-index { font-family: var(--ff-mono); font-size: var(--fs-xs); color: var(--ink-3); letter-spacing: 0.1em; }

/* stack controls */
.stack-ctrl {
  display: flex; align-items: center; justify-content: space-between; gap: 24px;
  margin-top: clamp(28px, 5vh, 48px);
}
.stack-counter { display: flex; align-items: baseline; gap: 8px; font-family: var(--ff-mono); }
.stack-counter .cur { font-size: clamp(1.8rem, 4vw, 2.6rem); font-weight: 700; letter-spacing: -0.02em; }
.stack-counter .sep { color: var(--ink-3); }
.stack-counter .tot { font-size: var(--fs-sm); color: var(--ink-3); }
.stack-dots { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; max-width: 46%; justify-content: center; }
.stack-dot { width: 7px; height: 7px; border-radius: 50%; background: var(--line); transition: width .35s var(--ease), background-color .35s var(--ease); cursor: pointer; }
.stack-dot.is-active { width: 26px; border-radius: 999px; background: var(--ink); }
.stack-arrows { display: flex; gap: 10px; }
.stack-arrow {
  width: 52px; height: 52px; border-radius: 50%;
  border: 1px solid var(--line); display: grid; place-items: center; color: var(--ink);
  transition: background-color .25s var(--ease), border-color .25s var(--ease), transform .25s var(--ease);
}
.stack-arrow:hover:not(:disabled) { background: var(--ink); color: var(--bg); border-color: var(--ink); }
.stack-arrow:active:not(:disabled) { transform: scale(0.94); }
.stack-arrow:disabled { opacity: 0.3; cursor: not-allowed; }
.stack-arrow .ico { width: 22px; height: 22px; }
.stack-hint { text-align: center; font-family: var(--ff-mono); font-size: var(--fs-xs); color: var(--ink-3); letter-spacing: 0.15em; text-transform: uppercase; }
.stack-foot { display: flex; align-items: center; justify-content: center; gap: 20px; margin-top: 18px; }
.stack-mode { display: inline-flex; align-items: center; gap: 6px; background: var(--surface); border: 1px solid var(--line-2); border-radius: 100px; padding: 6px 14px; cursor: pointer; color: var(--ink-2); font-size: var(--fs-xs); font-family: var(--ff-mono); letter-spacing: 0.08em; transition: all .25s var(--ease); }
.stack-mode:hover { background: var(--ink); color: var(--bg); border-color: var(--ink); }
.stack-mode:active { transform: scale(0.95); }
.stack-mode .ico { width: 15px; height: 15px; }
.stack-mode-label { min-width: 2em; }

/* ---------- Section header ---------- */
.sec { padding: clamp(56px, 10vh, 120px) 0; }
.sec-head { display: flex; align-items: flex-end; justify-content: space-between; gap: 32px; margin-bottom: clamp(36px, 6vh, 64px); flex-wrap: wrap; }
.sec-title { font-family: var(--ff-display); font-weight: 700; font-size: var(--fs-h1); line-height: 1.05; letter-spacing: -0.025em; text-wrap: balance; max-width: 18ch; }
.sec-lead { max-width: 40ch; color: var(--ink-2); font-size: var(--fs-lg); text-wrap: pretty; }

/* ---------- Capabilities ---------- */
.cap-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1px; background: var(--line-2); border: 1px solid var(--line-2); border-radius: var(--r-lg); overflow: hidden; }
.cap-card { background: var(--bg); padding: clamp(28px, 4vw, 44px); transition: background-color .3s var(--ease); }
.cap-card:hover { background: var(--surface); }
.cap-icon { width: 48px; height: 48px; border-radius: var(--r-sm); display: grid; place-items: center; background: var(--ink); color: var(--bg); margin-bottom: 22px; }
.cap-icon .ico { width: 22px; height: 22px; }
.cap-card h3 { font-family: var(--ff-display); font-weight: 700; font-size: var(--fs-h3); letter-spacing: -0.01em; }
.cap-en { font-family: var(--ff-mono); font-size: var(--fs-xs); color: var(--ink-3); letter-spacing: 0.1em; margin-top: 4px; }
.cap-card p { color: var(--ink-2); margin-top: 14px; max-width: 38ch; }
.cap-tags { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 20px; }
.cap-tag { font-family: var(--ff-mono); font-size: 0.7rem; padding: 0.35em 0.8em; border: 1px solid var(--line); border-radius: var(--r-pill); color: var(--ink-2); }

/* ---------- About ---------- */
.about-grid { display: grid; grid-template-columns: 1.1fr 0.9fr; gap: clamp(40px, 6vw, 90px); align-items: start; }
.about-lead { font-family: var(--ff-display); font-weight: 600; font-size: clamp(1.5rem, 2.6vw, 2.1rem); line-height: 1.3; letter-spacing: -0.02em; text-wrap: balance; }
.about-lead em { font-style: normal; color: var(--ink-3); }
.about-body p { color: var(--ink-2); margin-top: 20px; max-width: 52ch; }
.about-stats { display: grid; grid-template-columns: 1fr 1fr; gap: 1px; background: var(--line-2); border: 1px solid var(--line-2); border-radius: var(--r-lg); overflow: hidden; }
.about-stat { background: var(--bg); padding: clamp(24px, 3vw, 36px); }
.about-stat .n { font-family: var(--ff-mono); font-size: clamp(2rem, 4vw, 2.8rem); font-weight: 700; letter-spacing: -0.03em; }
.about-stat .l { font-family: var(--ff-mono); font-size: var(--fs-xs); color: var(--ink-3); letter-spacing: 0.16em; text-transform: uppercase; margin-top: 6px; }

/* process steps */
.steps { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; margin-top: 8px; }
.step { border-top: 1px solid var(--line); padding-top: 22px; }
.step-num { font-family: var(--ff-mono); font-size: var(--fs-xs); color: var(--ink-3); letter-spacing: 0.2em; }
.step h4 { font-family: var(--ff-display); font-weight: 700; font-size: 1.1rem; margin-top: 12px; }
.step p { color: var(--ink-2); font-size: var(--fs-sm); margin-top: 8px; }

/* ---------- Contact ---------- */
.contact-card {
  position: relative; overflow: hidden;
  border: 1px solid var(--line-2); border-radius: var(--r-xl);
  padding: clamp(40px, 7vw, 88px);
  background: var(--surface);
  box-shadow: var(--shadow-lg);
}
.contact-card::before {
  content: ""; position: absolute; inset: 0; z-index: 0; pointer-events: none;
  background: radial-gradient(80% 120% at 100% 0%, var(--bg-2) 0%, transparent 60%);
}
.contact-inner { position: relative; z-index: 1; display: grid; grid-template-columns: 1.2fr 0.8fr; gap: clamp(32px, 5vw, 72px); align-items: end; }
.contact-title { font-family: var(--ff-display); font-weight: 800; font-size: var(--fs-h1); line-height: 1; letter-spacing: -0.03em; text-wrap: balance; }
.contact-list { display: flex; flex-direction: column; gap: 18px; }
.contact-row { display: flex; align-items: center; gap: 14px; padding: 14px 0; border-top: 1px solid var(--line-2); }
.contact-row .ico { width: 20px; height: 20px; color: var(--ink-2); }
.contact-row .k { font-family: var(--ff-mono); font-size: var(--fs-xs); color: var(--ink-3); letter-spacing: 0.14em; text-transform: uppercase; width: 84px; flex: none; }
.contact-row .v { font-weight: 500; }

/* form */
.form { display: grid; gap: 16px; margin-top: 8px; }
.field { display: flex; flex-direction: column; gap: 7px; }
.field label { font-family: var(--ff-mono); font-size: var(--fs-xs); color: var(--ink-3); letter-spacing: 0.14em; text-transform: uppercase; }
.field input, .field textarea {
  font: inherit; color: var(--ink); background: var(--bg);
  border: 1px solid var(--line); border-radius: var(--r-sm);
  padding: 0.85em 1em; transition: border-color .25s var(--ease), box-shadow .25s var(--ease);
}
.field textarea { resize: vertical; min-height: 120px; }
.field input:focus, .field textarea:focus { outline: none; border-color: var(--ink); box-shadow: 0 0 0 3px var(--surface-3); }

/* ---------- Footer ---------- */
.footer { border-top: 1px solid var(--line-2); padding: clamp(48px, 7vw, 80px) 0 32px; margin-top: clamp(56px, 10vh, 120px); }
.footer-inner { display: grid; grid-template-columns: 1.3fr 2fr; gap: clamp(32px, 5vw, 72px); align-items: start; }
.footer-brand { display: flex; gap: 16px; align-items: flex-start; }
.footer-logo { width: 40px; height: 30px; object-fit: contain; }
.footer-logo.logo-dark { display: none; }
[data-theme="dark"] .footer-logo.logo-light { display: none; }
[data-theme="dark"] .footer-logo.logo-dark { display: inline-block; }
.footer-name { font-weight: 700; font-size: 1.1rem; }
.footer-tag { color: var(--ink-2); font-size: var(--fs-sm); margin-top: 6px; max-width: 34ch; }
.footer-wechat { color: var(--ink-2); font-size: var(--fs-sm); }
.footer-cols { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.footer-col { display: flex; flex-direction: column; gap: 10px; }
.footer-label { font-family: var(--ff-mono); font-size: var(--fs-xs); color: var(--ink-3); letter-spacing: 0.16em; text-transform: uppercase; margin-bottom: 4px; }
.footer-col a { color: var(--ink-2); font-size: var(--fs-sm); transition: color .2s var(--ease); width: fit-content; }
.footer-col a:hover { color: var(--ink); }
.footer-base { display: flex; align-items: center; justify-content: space-between; gap: 16px; margin-top: clamp(36px, 5vw, 56px); padding-top: 24px; border-top: 1px solid var(--line-2); font-size: var(--fs-xs); color: var(--ink-3); flex-wrap: wrap; }
.footer-mono { font-family: var(--ff-mono); letter-spacing: 0.14em; }

/* ---------- Reveal ---------- */
.reveal { opacity: 0; transform: translateY(26px); transition: opacity .8s var(--ease-out), transform .8s var(--ease-out); }
.reveal.is-in { opacity: 1; transform: none; }
.reveal[data-d="1"] { transition-delay: .08s; }
.reveal[data-d="2"] { transition-delay: .16s; }
.reveal[data-d="3"] { transition-delay: .24s; }
.reveal[data-d="4"] { transition-delay: .32s; }

/* ---------- Page hero (sub pages) ---------- */
.page-hero { padding: calc(var(--nav-h) + clamp(60px, 12vh, 130px)) 0 clamp(30px, 5vh, 60px); position: relative; overflow: hidden; }
.page-hero .hero-grid { opacity: .35; }
.page-title { font-family: var(--ff-display); font-weight: 800; font-size: var(--fs-hero); line-height: 0.98; letter-spacing: -0.03em; text-wrap: balance; max-width: 16ch; }
.page-lead { color: var(--ink-2); font-size: var(--fs-lg); max-width: 46ch; margin-top: 22px; text-wrap: pretty; }

/* ---------- Card Metrics & Detail ---------- */
.card-metrics { display: flex; gap: 0; margin-top: 16px; padding: 14px 0; border-top: 1px solid var(--line-2); border-bottom: 1px solid var(--line-2); }
.metric { flex: 1; text-align: center; }
.metric + .metric { border-left: 1px solid var(--line-2); }
.metric-val { display: block; font-family: var(--ff-mono); font-size: 1.1rem; font-weight: 700; color: var(--ink); letter-spacing: -0.02em; }
.metric-label { display: block; font-size: var(--fs-xs); color: var(--ink-3); margin-top: 2px; letter-spacing: 0.04em; }

/* card desc line clamp */
.card-desc { display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; text-overflow: ellipsis; }
.modal-desc-full { -webkit-line-clamp: unset; display: block; overflow: visible; }

/* card detail button */
.card-detail-btn { background: none; border: none; color: var(--ink-3); font-size: var(--fs-xs); font-family: var(--ff-mono); cursor: pointer; padding: 4px 8px; border-radius: var(--r-sm); transition: all .2s var(--ease); letter-spacing: 0.04em; }
.card-detail-btn:hover { color: var(--ink); background: var(--surface-2); }

/* ---------- Modal ---------- */
.modal-overlay { position: fixed; inset: 0; background: rgba(0,0,0,0.4); -webkit-backdrop-filter: blur(8px); backdrop-filter: blur(8px); display: flex; align-items: center; justify-content: center; z-index: 1000; opacity: 0; visibility: hidden; transition: opacity .3s var(--ease), visibility .3s; padding: 20px; }
.modal-overlay.is-open { opacity: 1; visibility: visible; }
.modal-card { background: var(--bg); border: 1px solid var(--line-2); border-radius: var(--r-lg); max-width: 520px; width: 100%; max-height: 85vh; overflow-y: auto; padding: 36px; position: relative; transform: translateY(20px) scale(0.96); transition: transform .35s var(--ease); box-shadow: 0 24px 80px rgba(0,0,0,0.18); }
.modal-overlay.is-open .modal-card { transform: translateY(0) scale(1); }
.modal-close { position: absolute; top: 16px; right: 16px; background: none; border: none; cursor: pointer; color: var(--ink-3); padding: 6px; border-radius: var(--r-sm); transition: all .2s; display: flex; align-items: center; justify-content: center; }
.modal-close:hover { color: var(--ink); background: var(--surface-2); }
.modal-close svg { width: 20px; height: 20px; }
.modal-section { margin-top: 20px; }
.modal-section-k { font-family: var(--ff-mono); font-size: var(--fs-xs); color: var(--ink-3); letter-spacing: 0.08em; text-transform: uppercase; margin-bottom: 6px; }
.modal-section-v { color: var(--ink-2); line-height: 1.7; font-size: var(--fs-sm); }
.modal-cta { margin-top: 24px; display: inline-flex; }
.modal-body .card-domain { margin-bottom: 4px; }
.modal-body .card-title { margin-top: 4px; }

/* ---------- Form ---------- */
.field-row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.field-tri { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 12px; }
.contact-hint { font-size: var(--fs-xs); color: var(--ink-3); margin-bottom: 8px; letter-spacing: 0.02em; }

/* ---------- Performance ---------- */
.sec { content-visibility: auto; contain-intrinsic-size: auto 600px; }
.stack-wrap { content-visibility: auto; contain-intrinsic-size: auto 700px; }
img { max-width: 100%; height: auto; }

/* ---------- Responsive ---------- */
@media (max-width: 980px) {
  .cap-grid { grid-template-columns: 1fr; }
  .about-grid { grid-template-columns: 1fr; }
  .steps { grid-template-columns: repeat(2, 1fr); }
  .contact-inner { grid-template-columns: 1fr; }
  .footer-inner { grid-template-columns: 1fr; }
}
@media (max-width: 760px) {
  .nav-links {
    position: fixed; top: var(--nav-h); left: 0; right: 0;
    flex-direction: column; align-items: stretch; gap: 0;
    background: var(--surface-2); -webkit-backdrop-filter: saturate(180%) blur(20px); backdrop-filter: saturate(180%) blur(20px);
    border-bottom: 1px solid var(--line-2);
    padding: 12px var(--gut) 20px; transform: translateY(-130%); transition: transform .4s var(--ease);
    z-index: 90;
  }
  .nav-links.is-open { transform: translateY(0); }
  .nav-link { padding: 0.9em 0.6em; font-size: var(--fs-body); border-bottom: 1px solid var(--line-2); border-radius: 0; }
  .nav-link.is-active::after { display: none; }
  .nav-cta { display: none; }
  .nav-burger { display: block; }
  .hero-top { flex-direction: column; align-items: flex-start; }
  .hero-meta { flex-wrap: wrap; gap: 24px 36px; }
  .stack-ctrl { flex-wrap: wrap; }
  .stack-dots { order: 3; max-width: 100%; margin-top: 8px; }
  .steps { grid-template-columns: 1fr; }
  .footer-cols { grid-template-columns: 1fr 1fr; }
  .field-row { grid-template-columns: 1fr; gap: 0; }
  .field-tri { grid-template-columns: 1fr; gap: 0; }
  .modal-card { padding: 24px; margin: 10px; }
  .modal-overlay { padding: 0; align-items: flex-end; }
  .modal-overlay.is-open .modal-card { transform: translateY(0); }
  .modal-card { transform: translateY(100%); border-radius: var(--r-lg) var(--r-lg) 0 0; }
  /* 移动端卡片优化：缩小尺寸、降低阴影复杂度 */
  .stack-card { width: min(380px, 88vw); margin-left: calc(min(380px, 88vw) / -2); margin-top: -180px; padding: clamp(22px, 5vw, 32px); }
  .stack { perspective: 900px; }
  .card-metrics { padding: 10px 0; }
  .metric-val { font-size: 1rem; }
  .metric-label { font-size: 0.75rem; }
  .card-detail { gap: 6px; }
  .detail-row { font-size: 0.85rem; }
  /* 降低动效复杂度 */
  .stack-card { transition: transform .4s var(--ease), opacity .35s var(--ease), filter .35s var(--ease); }
  .stack-card { --shadow-stack: 0 16px 48px rgba(0,0,0,0.12), 0 4px 12px rgba(0,0,0,0.06); }
  .hero-grid { opacity: 0.4; }
  .contact-inner { grid-template-columns: 1fr !important; }
}
@media (max-width: 480px) {
  .stack-card { margin-top: -190px; }
  .footer-cols { grid-template-columns: 1fr; }
  .footer-base { flex-direction: column; align-items: flex-start; }
}
@media (prefers-reduced-motion: reduce) {
  * { animation-duration: .001ms !important; transition-duration: .001ms !important; scroll-behavior: auto !important; }
  .reveal { opacity: 1; transform: none; }
}