/* Utra 落地页 v6 · 黑金版
   纯黑底 + 暖白文字 + 唯一强调色（logo 右下角那一块紫）；尺度收紧，留白克制 */

:root {
  --bg: #000;
  --bg-2: #0a0a0a;
  --ivory: #ece8e1;
  --ivory-2: #a19d96;
  --ivory-3: #67645f;
  --line: rgba(236, 232, 225, 0.08);
  --line-2: rgba(236, 232, 225, 0.16);
  --key: #8a83ff;
  --serif: 'Instrument Serif', 'Songti SC', 'Noto Serif SC', 'STSong', serif;
  --sans: 'Inter', -apple-system, 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  --mono: ui-monospace, 'SF Mono', 'JetBrains Mono', Menlo, Consolas, monospace;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; scroll-padding-top: 60px; }
body {
  background: var(--bg); color: var(--ivory);
  font: 14px/1.7 var(--sans);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
::selection { background: var(--key); color: #fff; }
a { color: inherit; text-decoration: none; }
code { font: 0.86em var(--mono); color: var(--key); }
.wrap { max-width: 1080px; margin: 0 auto; padding: 0 32px; }
.ic { width: 13px; height: 13px; fill: none; stroke: currentColor; stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; }
.label { font: 500 10.5px var(--mono); letter-spacing: .18em; text-transform: uppercase; color: var(--ivory-3); }
.m-br { display: none; }

/* ── 标志 ── */
.mark-key { fill: var(--key); }
.brand { display: inline-flex; align-items: center; gap: 9px; }
.brand-mark { width: 15px; height: 15px; color: var(--ivory); }
.brand-word { font: 400 20px/1 var(--serif); letter-spacing: .01em; }

/* ── 按钮 ── */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  height: 36px; padding: 0 16px; border-radius: 0;
  font: 500 12.5px var(--sans); letter-spacing: .04em; white-space: nowrap;
  transition: background .3s, color .3s, border-color .3s;
}
.btn.sm { height: 30px; padding: 0 12px; font-size: 12px; }
.btn.lg { height: 42px; padding: 0 22px; font-size: 13px; }
.btn .ic { transition: transform .3s; }
.btn:hover .ic { transform: translateX(3px); }
.btn-ivory { background: var(--ivory); color: #000; }
.btn-ivory:hover { background: #fff; }
.btn-key { background: var(--ivory); color: #000; }
.btn-key:hover { background: #fff; }
.btn-line { border: 1px solid var(--line-2); color: var(--ivory); }
.btn-line:hover { border-color: var(--ivory-2); }

/* ── 导航 ── */
.nav { position: fixed; inset: 0 0 auto 0; z-index: 50; transition: background .3s, border-color .3s; border-bottom: 1px solid transparent; }
.nav.scrolled { background: rgba(0, 0, 0, .72); backdrop-filter: blur(16px); -webkit-backdrop-filter: blur(16px); border-color: var(--line); }
.nav-in { height: 60px; display: flex; align-items: center; gap: 48px; }
.nav-links { display: flex; gap: 28px; font-size: 12.5px; color: var(--ivory-2); }
.nav-links a, .nav-login { transition: color .2s; }
.nav-links a:hover, .nav-login:hover { color: var(--ivory); }
.nav-act { margin-left: auto; display: flex; align-items: center; gap: 22px; }
.nav-login { font-size: 12.5px; color: var(--ivory-2); }

/* ── Hero ── */
.hero { position: relative; padding: 168px 0 72px; overflow: hidden; }
.hero-light {
  position: absolute; inset: 0; pointer-events: none;
  background: radial-gradient(520px 300px at 70% 34%, rgba(138, 131, 255, .045), transparent 70%);
}
.hero .wrap { position: relative; }
.hero-meta { display: flex; align-items: center; gap: 14px; font: 500 10.5px var(--mono); letter-spacing: .18em; text-transform: uppercase; color: var(--ivory-3); }
.hero-meta .sep { width: 28px; height: 1px; background: var(--line-2); }

.hero-word {
  position: relative; display: inline-block;
  margin: 22px 0 0 -0.04em;
  font: 400 clamp(96px, 15vw, 200px)/0.86 var(--serif);
  letter-spacing: -0.025em; color: var(--ivory);
}
.hero-key {
  display: inline-block; width: .15em; height: .15em; margin-left: .05em;
  background: var(--key); vertical-align: baseline;
}

.hero-foot {
  display: grid; grid-template-columns: 1fr 1fr; gap: 56px; align-items: end;
  margin-top: 56px; padding-top: 26px; border-top: 1px solid var(--line);
}
.hero-line { font: 400 clamp(22px, 2.2vw, 28px)/1.3 var(--serif); }
.hero-side p { color: var(--ivory-2); font-size: 13px; }
.cta { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 22px; }

/* ── 宣言 ── */
.manifesto { padding: 140px 0 110px; }
.manifesto-t {
  margin-top: 28px; max-width: 720px;
  font: 400 clamp(22px, 2.6vw, 34px)/1.45 var(--serif);
}
.manifesto-t em { font-style: italic; color: var(--key); }

/* ── 三条原则 ── */
.tenets { padding-bottom: 130px; }
.tenet-grid { display: grid; grid-template-columns: repeat(3, 1fr); }
.tenet { border-top: 1px solid var(--line); }
.tenet { padding: 34px 32px 4px 0; }
.tenet + .tenet { padding-left: 32px; border-left: 1px solid var(--line); }
.tenet .num { font: italic 400 16px var(--serif); color: var(--key); }
.tenet h3 { margin-top: 26px; font: 400 26px/1.1 var(--serif); }
.tenet .en { font: 500 10px var(--mono); letter-spacing: .18em; text-transform: uppercase; color: var(--ivory-3); margin: 6px 0 16px; }
.tenet p:last-child { color: var(--ivory-2); font-size: 13px; }

h2 { font: 400 clamp(28px, 3vw, 40px)/1.15 var(--serif); letter-spacing: -0.01em; }

/* ── 标志故事 ── */
.mark-story { padding: 120px 0; background: var(--bg-2); border-block: 1px solid var(--line); }
.story-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 80px; align-items: center; }
.story-visual { position: relative; aspect-ratio: 1; max-width: 320px; display: grid; place-items: center; border: 1px solid var(--line); }
.story-visual::before, .story-visual::after { content: ''; position: absolute; background: var(--line); }
.story-visual::before { left: 50%; top: 0; bottom: 0; width: 1px; }
.story-visual::after { top: 50%; left: 0; right: 0; height: 1px; }
.story-mark { position: relative; z-index: 1; width: 44%; height: 44%; color: var(--ivory); }
.story-mark .mark-key { transform-origin: 83% 83%; }
.story-visual.in .story-mark .mark-key { animation: key-in 1.4s .3s cubic-bezier(.2,.7,.2,1) both; }
@keyframes key-in { from { transform: translate(18%, 18%); opacity: 0; } to { transform: none; opacity: 1; } }
.story-tag { position: absolute; right: 12px; bottom: 8px; font: italic 400 14px var(--serif); color: var(--key); }
.story-copy h2 { margin: 22px 0 24px; }
.story-copy p:not(.label) { color: var(--ivory-2); font-size: 13.5px; max-width: 400px; }
.story-copy p + p { margin-top: 12px; }

/* ── 模型 ── */
.models { padding: 130px 0 110px; }
.sec-head { display: flex; align-items: baseline; gap: 24px; margin-bottom: 40px; }
.sec-head h2 { margin-right: auto; }
.sec-head .label { order: -1; width: 110px; flex: none; }
.more { font-size: 12px; color: var(--ivory-2); border-bottom: 1px solid var(--line-2); padding-bottom: 2px; transition: color .2s, border-color .2s; }
.more:hover { color: var(--ivory); border-color: var(--ivory); }
.index { list-style: none; border-top: 1px solid var(--line); }
.index li {
  display: grid; grid-template-columns: 110px 0.8fr 1fr 1.6fr; align-items: baseline; gap: 24px;
  padding: 22px 0; border-bottom: 1px solid var(--line);
}
.index .idx { font: 500 10.5px var(--mono); color: var(--ivory-3); }
.index .fam { font: 400 26px/1 var(--serif); transition: color .3s; }
.index li:hover .fam { font-style: italic; color: var(--key); }
.index .desc { color: var(--ivory-2); font-size: 12.5px; }
.index .ids { font: 11px/1.8 var(--mono); color: var(--ivory-3); }
.index-note { margin-top: 20px; padding-left: 134px; font-size: 12px; color: var(--ivory-3); }

/* ── 接入 ── */
.access { padding: 110px 0 130px; border-top: 1px solid var(--line); }
.access-grid { display: grid; grid-template-columns: 0.85fr 1.15fr; gap: 72px; align-items: center; }
.access-copy h2 { margin: 22px 0 18px; }
.access-copy > p:not(.label) { color: var(--ivory-2); font-size: 13.5px; max-width: 360px; }
.clients { list-style: none; display: flex; flex-wrap: wrap; gap: 6px 18px; margin-top: 30px; font-size: 12px; color: var(--ivory-3); }
.clients li::before { content: '/ '; color: var(--line-2); }

.console { border: 1px solid var(--line-2); background: #050505; min-width: 0; }
.console-bar { display: flex; align-items: center; justify-content: space-between; gap: 12px; padding: 0 10px 0 4px; border-bottom: 1px solid var(--line); }
.tabs { display: flex; overflow-x: auto; }
.tabs button {
  border: 0; background: none; cursor: pointer; white-space: nowrap;
  padding: 12px 12px 11px; font: 500 11.5px var(--sans); color: var(--ivory-3);
  border-bottom: 1px solid transparent; margin-bottom: -1px; transition: color .2s;
}
.tabs button:hover { color: var(--ivory-2); }
.tabs button.on { color: var(--ivory); border-color: var(--key); }
.copy {
  border: 1px solid var(--line-2); background: none; cursor: pointer; flex: none;
  padding: 3px 10px; font: 500 11px var(--sans); color: var(--ivory-2);
}
.copy:hover { color: var(--ivory); border-color: var(--ivory-2); }
.code { margin: 0; padding: 22px 22px; min-height: 196px; overflow-x: auto; font: 12px/1.85 var(--mono); color: #c8c6c0; white-space: pre; }
.code .k { color: var(--key); }
.code .s { color: #cfc2a4; }
.code .c { color: #55534f; }
.console-hint { padding: 11px 22px; border-top: 1px solid var(--line); font-size: 11.5px; color: var(--ivory-3); }

/* ── 承诺 ── */
.vows { border-block: 1px solid var(--line); }
.vow-row { display: grid; grid-template-columns: repeat(4, 1fr); }
.vow { padding: 30px 22px 32px 0; }
.vow + .vow { padding-left: 22px; border-left: 1px solid var(--line); }
.vow b { display: block; font: 400 18px/1.2 var(--serif); margin-bottom: 6px; }
.vow span { font-size: 12px; color: var(--ivory-3); }

/* ── 收口 ── */
.finale { position: relative; padding: 140px 0 0; overflow: hidden; }
.finale-in { position: relative; z-index: 1; text-align: center; display: flex; flex-direction: column; align-items: center; }
.finale-t { margin: 20px 0 6px; font-size: clamp(36px, 4.4vw, 56px); }
.finale .cta { justify-content: center; margin-top: 28px; }
.finale-word {
  margin-top: 80px; text-align: center; user-select: none;
  font: 400 clamp(140px, 24vw, 320px)/0.74 var(--serif); letter-spacing: -0.04em;
  color: transparent; -webkit-text-stroke: 1px rgba(236, 232, 225, .1);
  transform: translateY(14%);
}

/* ── 页脚 ── */
.foot { border-top: 1px solid var(--line); position: relative; background: var(--bg); }
.foot-in { display: flex; align-items: center; gap: 40px; padding-block: 28px; }
.foot-links { display: flex; flex-wrap: wrap; gap: 6px 22px; font-size: 12px; color: var(--ivory-2); }
.foot-links a:hover { color: var(--ivory); }
.foot-c { margin-left: auto; font-size: 11px; color: var(--ivory-3); }

/* ── 入场 ── */
.reveal { opacity: 0; transform: translateY(14px); transition: opacity 1.1s ease, transform 1.1s cubic-bezier(.2,.7,.2,1); }
.reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
  .story-visual.in .story-mark .mark-key { animation: none; }
}

/* ── 响应式 ── */
@media (max-width: 960px) {
  .wrap { padding: 0 24px; }
  .hero-foot { grid-template-columns: 1fr; gap: 22px; }
  .story-grid, .access-grid { grid-template-columns: 1fr; gap: 52px; }
  .story-visual { max-width: 280px; }
  .index li { grid-template-columns: 50px 1fr 1.4fr; }
  .index .desc { display: none; }
  .index-note { padding-left: 74px; }
  .sec-head .label { width: auto; }
  .vow-row { grid-template-columns: 1fr 1fr; }
  .vow:nth-child(3) { padding-left: 0; border-left: 0; }
  .vow:nth-child(n+3) { border-top: 1px solid var(--line); }
}
@media (max-width: 640px) {
  .wrap { padding: 0 20px; }
  .nav-links, .nav-login { display: none; }
  .hero { padding: 128px 0 52px; }
  .hero-word { font-size: 92px; }
  .hero-meta span:last-child, .hero-meta .sep { display: none; }
  .d-br { display: none; }
  .cta .btn { flex: 1; padding: 0 14px; }
  .manifesto { padding: 96px 0 80px; }
  .tenets { padding-bottom: 90px; }
  .tenet-grid { grid-template-columns: 1fr; }
  .tenet, .tenet + .tenet { padding: 28px 0; border-left: 0; }
  .tenet h3 { margin-top: 14px; }
  .mark-story, .models, .access { padding: 88px 0; }
  .sec-head { flex-wrap: wrap; gap: 12px 18px; }
  .sec-head .label { width: 100%; }
  .index li { grid-template-columns: 1fr; gap: 6px; padding: 20px 0; }
  .index .idx { display: none; }
  .index-note { padding-left: 0; }
  .code { padding: 18px; font-size: 11px; min-height: 170px; }
  .console-hint { padding: 10px 18px; }
  .vow-row { grid-template-columns: 1fr; }
  .vow, .vow + .vow { padding: 22px 0; border-left: 0; }
  .vow + .vow { border-top: 1px solid var(--line); }
  .finale { padding-top: 100px; }
  .finale-word { margin-top: 56px; }
  .foot-in { flex-direction: column; align-items: flex-start; gap: 16px; }
  .foot-c { margin-left: 0; }
}