/* =========================================================
   梧桐金雨官网 · 全站样式
   配色参考 DeepSeek：品牌蓝 #4D6BFE / 白底 / 近黑文字 / 浅灰卡片
   结构：1 设计令牌  2 基础  3 组件  4 区块  5 响应式
   ========================================================= */

/* 1. 设计令牌 ------------------------------------------------ */
:root {
  --ink: #1f1f1f;          /* 主文字 */
  --ink-2: #4c4c4c;
  --ink-3: #8a8a8a;
  --line: #ebedf0;
  --line-2: #dcdfe5;
  --bg: #ffffff;
  --bg-soft: #f6f7f9;      /* 交替区块底色 */
  --brand: #4d6bfe;        /* DeepSeek 品牌蓝：主按钮、强调 */
  --brand-hover: #3c5af0;
  --brand-deep: #3a55e8;   /* 白底上的蓝色小字 */
  --brand-soft: #edf0ff;   /* 浅蓝底：图标、标签 */
  --sky-soft: #f0f4ff;

  --radius: 16px;
  --radius-lg: 24px;
  --maxw: 1200px;
  --gutter: 24px;
  --header-h: 68px;
  --shadow: 0 1px 2px rgba(31, 31, 31, .04), 0 12px 32px -16px rgba(77, 107, 254, .22);
  --font: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB",
          "Microsoft YaHei", "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

/* 2. 基础 ---------------------------------------------------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; scroll-padding-top: var(--header-h); -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font);
  color: var(--ink);
  background: var(--bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
img { display: block; max-width: 100%; height: auto; }
a { color: inherit; text-decoration: none; }
button { font: inherit; }
:focus-visible { outline: 2px solid var(--brand); outline-offset: 3px; border-radius: 6px; }

.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 var(--gutter); }
.section { padding: 112px 0; }
.section--soft { background: var(--bg-soft); }

.eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 13px; font-weight: 600; letter-spacing: .16em; text-transform: uppercase;
  color: var(--brand-deep); margin-bottom: 14px;
}
.eyebrow::before { content: ""; width: 18px; height: 2px; border-radius: 2px; background: var(--brand); }
.h2 { font-size: clamp(28px, 4vw, 42px); line-height: 1.25; font-weight: 700; letter-spacing: -.01em; }
.lead { font-size: 17px; color: var(--ink-2); max-width: 720px; margin-top: 16px; }
.sec-head { margin-bottom: 56px; }
.sec-head--center { text-align: center; }
.sec-head--center .eyebrow { justify-content: center; }
.sec-head--center .lead { margin-left: auto; margin-right: auto; }
.text-brand { color: var(--brand); }

/* 3. 组件 ---------------------------------------------------- */
/* 按钮 */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 12px 24px; border-radius: 999px; font-weight: 600; font-size: 15px;
  border: 1px solid transparent; cursor: pointer;
  transition: transform .2s, box-shadow .2s, background .2s, border-color .2s;
}
.btn svg { width: 16px; height: 16px; }
.btn--primary { background: var(--brand); color: #fff; }
.btn--primary:hover { background: var(--brand-hover); transform: translateY(-1px); box-shadow: 0 10px 24px -10px rgba(77, 107, 254, .6); }
.btn--outline { background: #fff; color: var(--ink); border-color: var(--line-2); }
.btn--outline:hover { border-color: var(--brand); color: var(--brand); }
.btn--sm { padding: 8px 18px; font-size: 14px; }

/* 卡片 */
.card {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  transition: transform .25s, box-shadow .25s, border-color .25s;
}
.card:hover { transform: translateY(-3px); box-shadow: var(--shadow); border-color: var(--line-2); }

/* 图标底座 */
.ico {
  width: 44px; height: 44px; border-radius: 12px; display: grid; place-items: center;
  background: var(--brand-soft); color: var(--brand-deep); flex: none;
}
.ico svg { width: 22px; height: 22px; }

/* 标签 */
.chips { display: flex; flex-wrap: wrap; gap: 8px; }
.chip {
  font-size: 13px; padding: 4px 12px; border-radius: 8px;
  background: var(--bg-soft); border: 1px solid var(--line); color: var(--ink-2);
}

/* 滚动渐显（由 JS 加 .is-in；无 JS 时内容正常显示） */
.js .reveal { opacity: 0; transform: translateY(20px); transition: opacity .7s ease, transform .7s ease; }
.js .reveal.is-in { opacity: 1; transform: none; }

/* 4. 区块 ---------------------------------------------------- */
/* 4.1 页头 */
.header {
  position: fixed; inset: 0 0 auto; z-index: 50; height: var(--header-h);
  background: rgba(255, 255, 255, .72);
  backdrop-filter: saturate(180%) blur(16px); -webkit-backdrop-filter: saturate(180%) blur(16px);
  border-bottom: 1px solid transparent; transition: border-color .3s, background .3s;
}
.header.is-scrolled { border-color: var(--line); background: rgba(255, 255, 255, .9); }
.header .wrap { display: flex; align-items: center; justify-content: space-between; height: 100%; gap: 24px; }
.brand { display: flex; align-items: center; gap: 14px; flex: none; }
.brand img { height: 40px; width: auto; }
.brand-name { font-size: 15px; font-weight: 600; padding-left: 14px; border-left: 1px solid var(--line-2); line-height: 1.2; }
.brand-name small { display: block; font-size: 11px; font-weight: 400; color: var(--ink-3); letter-spacing: .04em; }
.nav { display: flex; gap: 32px; font-size: 15px; color: var(--ink-2); }
.nav a { position: relative; padding: 4px 0; transition: color .2s; }
.nav a:hover, .nav a.is-active { color: var(--brand); }
.nav a::after {
  content: ""; position: absolute; left: 0; right: 0; bottom: -2px; height: 2px; border-radius: 2px;
  background: var(--brand); transform: scaleX(0); transition: transform .25s;
}
.nav a:hover::after, .nav a.is-active::after { transform: scaleX(1); }
.menu-btn { display: none; background: none; border: 0; padding: 8px; margin-right: -8px; cursor: pointer; color: var(--ink); }
.menu-btn svg { width: 24px; height: 24px; }

/* 4.2 首屏 */
.hero {
  position: relative; overflow: hidden; isolation: isolate;
  padding: calc(var(--header-h) + 96px) 0 88px;
  background:
    radial-gradient(60% 55% at 50% 0%, var(--brand-soft) 0%, transparent 72%),
    #fff;
}
.hero::before { /* 细网格纹理 */
  content: ""; position: absolute; inset: 0; z-index: -1;
  background-image: linear-gradient(var(--line) 1px, transparent 1px), linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 56px 56px;
  mask-image: radial-gradient(70% 60% at 50% 30%, #000 0%, transparent 75%);
  -webkit-mask-image: radial-gradient(70% 60% at 50% 30%, #000 0%, transparent 75%);
  opacity: .5;
}
.hero-canvas { position: absolute; inset: 0; z-index: -1; width: 100%; height: 100%; pointer-events: none; }
.hero-inner { text-align: center; }
.badge {
  display: inline-flex; align-items: center; gap: 8px; padding: 6px 14px 6px 8px; border-radius: 999px;
  background: #fff; border: 1px solid var(--line-2); font-size: 13px; color: var(--ink-2); margin-bottom: 28px;
  box-shadow: 0 4px 16px -8px rgba(77, 107, 254, .2);
}
.badge b { font-weight: 600; font-size: 12px; padding: 1px 8px; border-radius: 999px; background: var(--brand); color: #fff; }
.hero h1 { font-size: clamp(38px, 7vw, 76px); line-height: 1.12; font-weight: 800; letter-spacing: -.02em; }
.hero-sub { font-size: clamp(16px, 2vw, 19px); color: var(--ink-2); max-width: 700px; margin: 24px auto 0; }
.hero .chips { justify-content: center; margin-top: 26px; }
.hero .chip { background: rgba(255, 255, 255, .85); }
.hero-ctas { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; margin-top: 36px; }

.stats {
  display: grid; grid-template-columns: repeat(4, 1fr); margin-top: 80px;
  background: rgba(255, 255, 255, .85); border: 1px solid var(--line); border-radius: 20px;
  box-shadow: var(--shadow);
}
.stat { padding: 28px 20px; text-align: center; }
.stat + .stat { border-left: 1px solid var(--line); }
.stat-num { display: block; font-size: clamp(30px, 3.6vw, 42px); font-weight: 700; line-height: 1.15; font-variant-numeric: tabular-nums; }
.stat-num sup { font-size: .55em; color: var(--brand); margin-left: 2px; }
.stat-label { font-size: 14px; color: var(--ink-3); }

/* 4.3 关于 */
.about { display: grid; grid-template-columns: 1.1fr 1fr; gap: 64px; align-items: start; }
.about-text p { color: var(--ink-2); margin-top: 18px; }
.about-text strong { color: var(--ink); }
.formula { display: flex; flex-wrap: wrap; align-items: center; gap: 10px; margin-top: 28px; }
.formula span { padding: 8px 16px; border-radius: 10px; background: var(--bg-soft); border: 1px solid var(--line); font-weight: 600; }
.formula i { font-style: normal; color: var(--brand); font-weight: 700; }
.mvv { display: grid; gap: 16px; }
.mvv .card { padding: 24px 28px; }
.mvv-k { font-size: 12px; font-weight: 600; letter-spacing: .1em; color: var(--brand-deep); }
.mvv h3 { font-size: 19px; margin: 6px 0; }
.mvv p { font-size: 14.5px; color: var(--ink-2); }
.mvv .chips { margin-top: 10px; }
.mvv .chip { background: var(--brand-soft); border-color: transparent; color: var(--brand-deep); font-weight: 500; }

/* 4.4 优势 */
.adv-grid { display: grid; grid-template-columns: repeat(5, 1fr); gap: 16px; }
.adv { padding: 28px 22px; position: relative; overflow: hidden; }
.adv-no { font-size: 13px; font-weight: 700; color: var(--brand); font-variant-numeric: tabular-nums; }
.adv h3 { font-size: 17px; margin: 14px 0 8px; }
.adv p { font-size: 14px; color: var(--ink-2); }

/* 4.5 能力全景 */
.cap { display: grid; grid-template-columns: 1.65fr 1fr; gap: 40px; align-items: center; }
.layers { display: flex; flex-direction: column; gap: 10px; }
.layer {
  display: grid; grid-template-columns: 112px 1fr; gap: 16px; align-items: center;
  padding: 14px 18px; border-radius: 14px; background: #fff; border: 1px solid var(--line);
  transition: border-color .25s, box-shadow .25s;
}
.layer:hover { border-color: var(--brand); box-shadow: 0 8px 24px -16px rgba(77, 107, 254, .5); }
.layer-name { font-weight: 600; font-size: 15px; line-height: 1.3; }
.layer-name small { display: block; font-size: 11px; letter-spacing: .14em; color: var(--ink-3); font-weight: 500; }
.layer--top { background: linear-gradient(90deg, var(--brand-soft), #fff 80%); border-color: #d6ddff; }
.layer--top .chip { background: #fff; border-color: #d6ddff; color: var(--brand-deep); }
.traits { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.trait { padding: 22px; }
.trait h4 { font-size: 17px; margin-bottom: 4px; }
.trait p { font-size: 13.5px; color: var(--ink-2); }

/* 4.6 技术方向 */
.tech-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.tech { padding: 30px 28px; display: flex; flex-direction: column; }
.tech .ico { margin-bottom: 20px; }
.tech h3 { font-size: 19px; margin-bottom: 8px; }
.tech p { font-size: 14.5px; color: var(--ink-2); flex: 1; }
.tech-land { margin-top: 18px; padding-top: 14px; border-top: 1px dashed var(--line-2); font-size: 13px; color: var(--ink-3); }
.tech-land b { color: var(--brand-deep); margin-right: 6px; }

/* 4.7 多智能体 */
.flow { display: grid; grid-template-columns: repeat(5, 1fr); position: relative; margin-bottom: 28px; }
.flow::before {
  content: ""; position: absolute; top: 31px; left: 10%; right: 10%; height: 2px;
  background: repeating-linear-gradient(90deg, var(--brand) 0 8px, transparent 8px 14px); opacity: .4;
}
.flow-step { text-align: center; padding: 0 8px; position: relative; }
.flow-dot {
  width: 62px; height: 62px; margin: 0 auto 14px; border-radius: 18px; display: grid; place-items: center;
  background: #fff; border: 1px solid var(--line-2); font-weight: 700; color: var(--ink-2); position: relative;
}
.flow-step--key .flow-dot { background: var(--brand); color: #fff; border-color: var(--brand); box-shadow: 0 10px 24px -10px rgba(77, 107, 254, .7); }
.flow-step h4 { font-size: 16px; }
.flow-step p { font-size: 13px; color: var(--ink-2); }
.toolbar {
  display: flex; flex-wrap: wrap; justify-content: center; align-items: center; gap: 10px;
  padding: 18px; margin-bottom: 40px; border-radius: 14px; border: 1px dashed var(--line-2); background: #fff;
}
.toolbar-label { font-size: 13px; color: var(--ink-3); margin-right: 4px; }
.principles { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.principle { padding: 24px; }
.principle h4 { font-size: 16px; margin-bottom: 6px; display: flex; align-items: center; gap: 8px; }
.principle h4::before { content: ""; width: 8px; height: 8px; border-radius: 2px; background: var(--brand); }
.principle p { font-size: 14px; color: var(--ink-2); }

/* 4.8 模型工程 */
.pipe { display: grid; grid-template-columns: repeat(6, 1fr); gap: 12px; }
.pipe-step { padding: 24px 20px; }
.pipe-n { font-size: 28px; font-weight: 800; line-height: 1; }
.pipe-step h4 { font-size: 16px; margin: 12px 0 6px; }
.pipe-step p { font-size: 13.5px; color: var(--ink-2); }
.pipe-extra { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; margin-top: 20px; }
.pipe-extra > div { padding: 28px; border-radius: var(--radius); background: #fff; border: 1px solid var(--line); }
.pipe-extra h4 { font-size: 18px; margin-bottom: 8px; }
.pipe-extra p { font-size: 14.5px; color: var(--ink-2); }

/* 4.9 产品 */
.prod-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.prod { padding: 30px 28px; position: relative; overflow: hidden; }
.prod::after {
  content: ""; position: absolute; left: 0; top: 0; height: 3px; width: 100%;
  background: var(--brand); transform: scaleX(0); transform-origin: left; transition: transform .4s;
}
.prod:hover::after { transform: scaleX(1); }
.tag { display: inline-block; font-size: 12px; padding: 2px 10px; border-radius: 6px; font-weight: 600; letter-spacing: .06em; }
.tag--product { background: var(--brand); color: #fff; }
.tag--solution { background: var(--brand-soft); color: var(--brand-deep); }
.prod h3 { font-size: 20px; margin: 16px 0 8px; }
.prod p { font-size: 14.5px; color: var(--ink-2); }

/* 4.10 行业 */
.ind-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 1px;
  background: var(--line); border: 1px solid var(--line); border-radius: 20px; overflow: hidden;
}
.ind { background: #fff; padding: 34px 30px; transition: background .25s; }
.ind:hover { background: var(--bg-soft); }
.ind .ico { margin-bottom: 18px; }
.ind h3 { font-size: 19px; margin-bottom: 6px; }
.ind p { font-size: 14.5px; color: var(--ink-2); }

/* 4.11 案例 */
.tabs { display: flex; gap: 8px; margin-bottom: 24px; overflow-x: auto; scrollbar-width: none; }
.tabs::-webkit-scrollbar { display: none; }
.tab {
  flex: none; border: 1px solid var(--line-2); background: #fff; padding: 9px 18px; border-radius: 999px;
  font-size: 14px; color: var(--ink-2); cursor: pointer; transition: all .2s;
}
.tab:hover { color: var(--brand); border-color: var(--brand); }
.tab[aria-selected="true"] { background: var(--brand); border-color: var(--brand); color: #fff; }
.panel { display: grid; grid-template-columns: 1fr 1.15fr; gap: 40px; padding: 44px; border-radius: var(--radius-lg); }
.panel:hover { transform: none; }
.panel[hidden] { display: none; }
.panel.is-enter { animation: panel-in .4s ease; }
@keyframes panel-in { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: none; } }
.panel-meta { font-size: 12px; color: var(--brand-deep); font-weight: 600; letter-spacing: .12em; }
.panel h3 { font-size: 28px; margin: 6px 0 2px; }
.panel-sub { color: var(--ink-3); margin-bottom: 16px; }
.panel-desc { color: var(--ink-2); }
.kv { display: grid; grid-template-columns: auto 1fr; gap: 10px 18px; margin-top: 22px; font-size: 14px; }
.kv dt { color: var(--ink-3); }
.kv dd { font-weight: 500; }
.feat { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; align-content: start; }
.feat > div { padding: 18px; border-radius: 14px; background: var(--bg-soft); border: 1px solid var(--line); }
.feat h5 { font-size: 15px; margin-bottom: 4px; }
.feat h5 i { font-style: normal; font-size: 12px; color: var(--brand-deep); margin-right: 6px; }
.feat p { font-size: 13.5px; color: var(--ink-2); }

/* 4.12 服务 */
.svc-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.svc { padding: 28px 26px; }
.svc-n { font-size: 13px; font-weight: 700; color: var(--brand); }
.svc h3 { font-size: 20px; margin: 8px 0 14px; }
.svc ul { list-style: none; display: grid; gap: 8px; }
.svc li { font-size: 14px; color: var(--ink-2); padding-left: 16px; position: relative; }
.svc li::before { content: ""; position: absolute; left: 0; top: .72em; width: 6px; height: 6px; border-radius: 50%; background: var(--brand); }
.levels { display: grid; grid-template-columns: repeat(4, 1fr); margin-top: 20px; border: 1px solid var(--line); border-radius: 20px; overflow: hidden; background: #fff; }
.level { padding: 24px 26px; }
.level + .level { border-left: 1px solid var(--line); }
.level b { display: inline-block; font-size: 12px; padding: 1px 10px; border-radius: 6px; background: var(--brand-soft); color: var(--brand-deep); margin-bottom: 10px; }
.level h4 { font-size: 17px; margin-bottom: 4px; }
.level p { font-size: 13.5px; color: var(--ink-2); }

/* 4.13 商务合作表单 */
.contact {
  display: grid; grid-template-columns: 1fr 1.25fr; gap: 56px; align-items: start;
  padding: 56px; border-radius: 28px; border: 1px solid #dfe5ff;
  background: radial-gradient(60% 80% at 0% 0%, var(--brand-soft), transparent 70%), #fff;
}
.contact-points { list-style: none; display: grid; gap: 20px; margin-top: 32px; }
.contact-points li { display: flex; gap: 14px; align-items: flex-start; }
.contact-points .ico { width: 36px; height: 36px; border-radius: 10px; }
.contact-points .ico svg { width: 18px; height: 18px; }
.contact-points b { font-size: 15px; }
.contact-points p { font-size: 14px; color: var(--ink-2); }
.contact-card { padding: 32px; }
.contact-card:hover { transform: none; }

.form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 4px 16px; }
.field--full { grid-column: 1 / -1; }
.field label { display: block; font-size: 14px; font-weight: 500; margin-bottom: 6px; }
.field label em { font-style: normal; color: #e5484d; margin-left: 2px; }
.field input, .field select, .field textarea {
  width: 100%; font: inherit; font-size: 15px; color: var(--ink);
  padding: 10px 14px; border-radius: 10px; border: 1px solid var(--line-2); background: #fff;
  transition: border-color .2s, box-shadow .2s; -webkit-appearance: none; appearance: none;
}
.field select {
  padding-right: 36px; cursor: pointer;
  background: #fff url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%238a8a8a' stroke-width='2.5' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E") no-repeat right 14px center;
}
.field textarea { resize: vertical; min-height: 112px; line-height: 1.6; }
.field input::placeholder, .field textarea::placeholder { color: #b3b3b3; }
.field input:focus, .field select:focus, .field textarea:focus {
  outline: none; border-color: var(--brand); box-shadow: 0 0 0 3px rgba(77, 107, 254, .15);
}
.field.is-invalid input, .field.is-invalid select, .field.is-invalid textarea { border-color: #e5484d; }
.field.is-invalid input:focus, .field.is-invalid select:focus, .field.is-invalid textarea:focus { box-shadow: 0 0 0 3px rgba(229, 72, 77, .15); }
.field-err { min-height: 20px; font-size: 12.5px; color: #e5484d; line-height: 20px; }
.hp { position: absolute; left: -9999px; width: 1px; height: 1px; overflow: hidden; }
.agree { display: flex; gap: 8px; align-items: flex-start; font-size: 13.5px; color: var(--ink-2); cursor: pointer; margin-top: 4px; }
.agree input { width: 16px; height: 16px; margin-top: 3px; accent-color: var(--brand); flex: none; }
.form-submit { width: 100%; margin-top: 8px; padding: 13px 24px; }
.form-submit[disabled] { opacity: .65; cursor: not-allowed; transform: none; box-shadow: none; }
.form-submit .spinner { width: 16px; height: 16px; border-radius: 50%; border: 2px solid rgba(255,255,255,.4); border-top-color: #fff; animation: spin .8s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }
.form-result { padding: 12px 16px; border-radius: 10px; font-size: 14px; margin-bottom: 20px; }
.form-result.is-error { background: #fff0f0; color: #c9353a; border: 1px solid #ffd6d8; }
.form-done { text-align: center; padding: 32px 8px; }
.form-done:focus { outline: none; }
.form-done .ico { width: 56px; height: 56px; border-radius: 50%; margin: 0 auto 18px; }
.form-done .ico svg { width: 28px; height: 28px; }
.form-done h3 { font-size: 22px; margin-bottom: 8px; }
.form-done p { color: var(--ink-2); font-size: 15px; }
.form-done .btn { margin-top: 24px; }

/* 4.14 页脚 */
.footer { background: var(--bg-soft); border-top: 1px solid var(--line); padding: 56px 0 32px; font-size: 14px; color: var(--ink-2); }
.footer-grid { display: grid; grid-template-columns: 1.5fr repeat(3, 1fr); gap: 40px; }
.footer-brand img { height: 36px; width: auto; margin-bottom: 16px; }
.footer h5 { font-size: 14px; color: var(--ink); margin-bottom: 14px; }
.footer ul { list-style: none; display: grid; gap: 8px; }
.footer a:hover { color: var(--brand); }
.footer-bottom {
  display: flex; flex-direction: column; align-items: center; gap: 8px; text-align: center;
  margin-top: 40px; padding-top: 22px; border-top: 1px solid var(--line); font-size: 13px; color: var(--ink-3);
}
.footer-icp { display: flex; justify-content: center; flex-wrap: wrap; gap: 4px 20px; }

/* 5. 响应式 -------------------------------------------------- */
@media (max-width: 1080px) {
  .adv-grid { grid-template-columns: repeat(3, 1fr); }
  .pipe { grid-template-columns: repeat(3, 1fr); }
  .cap { grid-template-columns: 1fr; }
  .nav { gap: 22px; }
}

/* 平板 / 手机：折叠导航 */
@media (max-width: 900px) {
  :root { --header-h: 60px; }
  .section { padding: 80px 0; }
  .brand img { height: 34px; }
  .header .btn { display: none; }
  .menu-btn { display: block; }
  .nav {
    position: absolute; top: var(--header-h); left: 0; right: 0;
    flex-direction: column; gap: 0; padding: 8px var(--gutter) 16px;
    background: #fff; border-bottom: 1px solid var(--line); box-shadow: 0 16px 32px -20px rgba(26, 26, 29, .25);
    visibility: hidden; opacity: 0; transform: translateY(-8px); transition: opacity .2s, transform .2s, visibility .2s;
  }
  .nav a { padding: 14px 0; border-bottom: 1px solid var(--line); font-size: 16px; color: var(--ink); }
  .nav a:last-child { border-bottom: 0; }
  .nav a::after { display: none; }
  .header.is-open { background: #fff; border-color: var(--line); }
  .header.is-open .nav { visibility: visible; opacity: 1; transform: none; }

  .hero { padding: calc(var(--header-h) + 64px) 0 64px; }
  .stats { grid-template-columns: repeat(2, 1fr); margin-top: 56px; }
  .stat:nth-child(3) { border-left: 0; }
  .stat:nth-child(n+3) { border-top: 1px solid var(--line); }

  .about, .panel, .contact { grid-template-columns: 1fr; }
  .contact { padding: 36px; gap: 32px; }
  .about { gap: 40px; }
  .panel { padding: 28px; gap: 28px; }
  .tech-grid, .prod-grid, .ind-grid, .principles, .svc-grid { grid-template-columns: 1fr 1fr; }
  .levels { grid-template-columns: 1fr 1fr; }
  .level:nth-child(3) { border-left: 0; }
  .level:nth-child(n+3) { border-top: 1px solid var(--line); }

  .flow { grid-template-columns: 1fr; gap: 14px; }
  .flow::before { top: 31px; bottom: 31px; left: 31px; right: auto; width: 2px; height: auto;
    background: repeating-linear-gradient(180deg, var(--brand) 0 8px, transparent 8px 14px); }
  .flow-step { display: grid; grid-template-columns: 62px 1fr; gap: 16px; align-items: center; text-align: left; padding: 0; }
  .flow-dot { margin: 0; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .footer-brand { grid-column: 1 / -1; }
}

/* 手机 */
@media (max-width: 560px) {
  :root { --gutter: 16px; }
  .section { padding: 64px 0; }
  .sec-head { margin-bottom: 36px; }
  .lead { font-size: 15.5px; }
  .brand-name { display: none; }
  .hero-ctas .btn { flex: 1; }
  .adv-grid, .tech-grid, .prod-grid, .ind-grid, .principles, .svc-grid,
  .pipe, .pipe-extra, .traits, .levels { grid-template-columns: 1fr; }
  .pipe { grid-template-columns: 1fr 1fr; }
  .feat { grid-template-columns: 1fr; }
  .level + .level { border-left: 0; border-top: 1px solid var(--line); }
  .layer { grid-template-columns: 1fr; gap: 8px; }
  .panel { padding: 22px; }
  .panel h3 { font-size: 24px; }
  .contact { padding: 24px 16px; border-radius: 20px; }
  .contact-card { padding: 20px; }
  .form-grid { grid-template-columns: 1fr; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
  .js .reveal { opacity: 1; transform: none; }
}