/* ==========================================================================
   算数·海辕 二手车 · 产品介绍站
   深蓝（#0b1220）+ 青绿（#14b8a6）；不使用外部字体与外部图片，全部本地资源。
   ========================================================================== */

:root {
  --ink: #0b1220;
  --ink-2: #111c2e;
  --ink-3: #1b2838;
  --teal: #14b8a6;
  --teal-deep: #0f766e;
  --teal-dark: #0b5f59;
  --teal-soft: #ccfbf1;
  --teal-wash: #f0fdfa;
  --paper: #ffffff;
  --paper-2: #f6f9fb;
  --line: #e3eaf1;
  --line-soft: #eef3f7;
  --text: #17212f;
  --muted: #5f6f80;
  --muted-2: #8595a6;
  --amber: #d97706;
  --rose: #be123c;
  --radius: 18px;
  --radius-sm: 12px;
  --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.04), 0 6px 18px -12px rgba(15, 23, 42, 0.18);
  --shadow-md: 0 18px 40px -28px rgba(15, 23, 42, 0.35), 0 2px 8px -4px rgba(15, 23, 42, 0.08);
  --shadow-lg: 0 40px 80px -50px rgba(11, 18, 32, 0.6);
  --font: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Source Han Sans SC",
    "Noto Sans CJK SC", "Helvetica Neue", Arial, sans-serif;
  --mono: "SFMono-Regular", "JetBrains Mono", Consolas, "Liberation Mono", Menlo, monospace;
}

*,
*::before,
*::after { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; scroll-padding-top: 92px; }

body {
  margin: 0;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.7;
  color: var(--text);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img { max-width: 100%; height: auto; display: block; }
a { color: var(--teal-deep); text-decoration: none; }
a:hover { color: var(--teal-dark); }
h1, h2, h3, h4 { margin: 0; line-height: 1.25; letter-spacing: -0.01em; font-weight: 700; }
p { margin: 0; }
ul, ol { margin: 0; padding: 0; }
button { font: inherit; }

.container { width: min(1180px, calc(100% - 48px)); margin-inline: auto; }
.container--narrow { width: min(900px, calc(100% - 48px)); }
.sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0;
}
.skip-link {
  position: absolute; left: 16px; top: -60px; z-index: 200;
  background: var(--ink); color: #fff; padding: 10px 16px; border-radius: 10px;
  transition: top .18s ease;
}
.skip-link:focus { top: 12px; color: #fff; }

/* ---------------------------------------------------------------- 顶部导航 */
.site-header {
  position: sticky;
  top: 0;
  z-index: 80;
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid rgba(226, 232, 240, 0.9);
}
.header-inner {
  display: flex;
  align-items: center;
  gap: 24px;
  min-height: 72px;
}
.brand { display: inline-flex; align-items: center; gap: 10px; flex: 0 0 auto; }
.brand:hover { color: inherit; }
.brand-mark {
  width: 38px; height: 38px; border-radius: 11px;
  background: linear-gradient(155deg, #132033, #0b1220 70%);
  display: grid; place-items: center;
  box-shadow: inset 0 0 0 1px rgba(20, 184, 166, 0.35);
}
.brand-mark svg { width: 24px; height: 24px; }
.brand-text { display: flex; flex-direction: column; line-height: 1.2; }
.brand-name { font-size: 15.5px; font-weight: 700; color: var(--ink); letter-spacing: .01em; }
.brand-sub { font-size: 11.5px; color: var(--muted-2); letter-spacing: .08em; }

.site-header.is-scrolled { box-shadow: 0 10px 26px -24px rgba(11, 18, 32, 0.7); }
.nav-link[aria-current="true"] { color: var(--teal-deep); font-weight: 600; }

.nav--site { margin-left: auto; }
.nav-list { display: flex; align-items: center; gap: 2px; list-style: none; }
.nav-item { position: relative; }
.nav-link {
  display: inline-flex; align-items: center; gap: 5px;
  padding: 10px 12px; border-radius: 10px;
  font-size: 14.5px; color: #2b3948; white-space: nowrap;
  transition: background .16s, color .16s;
}
.nav-link:hover, .nav-link:focus-visible { background: var(--paper-2); color: var(--ink); }
.nav-item.is-current > .nav-link { color: var(--teal-deep); font-weight: 600; }
.caret {
  width: 6px; height: 6px; margin-left: 2px;
  border-right: 1.6px solid currentColor; border-bottom: 1.6px solid currentColor;
  transform: rotate(45deg) translateY(-1px); opacity: .55;
  transition: transform .18s ease;
}
.nav-item:hover .caret, .nav-item.is-open .caret { transform: rotate(225deg) translateY(-2px); }

.nav-panel {
  position: absolute; top: calc(100% - 4px); left: 50%;
  width: max-content; max-width: min(860px, calc(100vw - 48px));
  transform: translate(-50%, -6px);
  padding-top: 10px;
  opacity: 0; visibility: hidden; pointer-events: none;
  transition: opacity .16s ease, transform .18s ease, visibility .16s;
  z-index: 90;
}
.nav-item:hover > .nav-panel,
.nav-item:focus-within > .nav-panel,
.nav-item.is-open > .nav-panel {
  opacity: 1; visibility: visible; pointer-events: auto;
  transform: translate(-50%, 0);
}
.nav-panel__card {
  display: grid; grid-template-columns: minmax(0, 1fr) 236px; gap: 22px;
  padding: 20px 20px 20px 22px;
  background: #fff; border: 1px solid var(--line); border-radius: 16px;
  box-shadow: 0 30px 70px -34px rgba(11, 18, 32, 0.45), 0 4px 14px -10px rgba(11, 18, 32, 0.18);
}
.nav-panel__links { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 2px 12px; }
.nav-panel__links--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.nav-panel__group {
  grid-column: 1 / -1;
  margin: 6px 0 4px; padding: 0 8px;
  font-size: 11px; letter-spacing: .12em; text-transform: uppercase; color: var(--muted-2);
}
.nav-panel__group:first-child { margin-top: 0; }
.nav-panel__links a {
  display: grid; gap: 2px; padding: 8px 10px; border-radius: 10px;
  border-left: 2px solid transparent;
  transition: background .15s, border-color .15s;
}
.nav-panel__links a:hover { background: var(--teal-wash); border-left-color: var(--teal); }
.nav-panel__links strong { font-size: 13.5px; font-weight: 600; color: var(--ink); }
.nav-panel__links em { font-style: normal; font-size: 12px; color: var(--muted); line-height: 1.5; }
.nav-panel__feature {
  display: flex; flex-direction: column; gap: 8px;
  padding: 10px; border-radius: 13px; background: var(--paper-2);
  border: 1px solid var(--line-soft);
}
.nav-panel__feature img { width: 100%; aspect-ratio: 16 / 10; object-fit: cover; border-radius: 9px; }
.nav-panel__feature strong { font-size: 13.5px; color: var(--ink); padding-inline: 4px; }
.nav-panel__feature em { font-style: normal; font-size: 12px; color: var(--muted); padding-inline: 4px; }

.header-actions { display: flex; align-items: center; gap: 8px; flex: 0 0 auto; }

/* 按钮 */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 7px;
  padding: 10px 18px; border-radius: 999px;
  font-size: 14px; font-weight: 600; line-height: 1.4;
  border: 1px solid transparent; cursor: pointer;
  transition: transform .16s, box-shadow .18s, background .18s, color .18s, border-color .18s;
  white-space: nowrap;
}
.btn:hover { transform: translateY(-1px); }
.btn--primary { background: var(--teal-deep); color: #fff; box-shadow: 0 10px 22px -14px rgba(15, 118, 110, 0.9); }
.btn--primary:hover { background: var(--teal-dark); color: #fff; }
.btn--dark { background: var(--ink); color: #fff; }
.btn--dark:hover { background: var(--ink-2); color: #fff; }
.btn--ghost { background: #fff; color: var(--ink); border-color: #d8e1ea; }
.btn--ghost:hover { border-color: #b9c8d6; color: var(--ink); background: #fbfdfe; }
.btn--light { background: rgba(255, 255, 255, 0.1); color: #e6eef5; border-color: rgba(255, 255, 255, 0.22); }
.btn--light:hover { background: rgba(255, 255, 255, 0.16); color: #fff; }
.btn--lg { padding: 13px 24px; font-size: 15px; }
.btn--sm { padding: 7px 13px; font-size: 13px; }

.nav-toggle {
  display: none; width: 42px; height: 42px; border-radius: 11px;
  border: 1px solid var(--line); background: #fff; cursor: pointer;
  align-items: center; justify-content: center; flex-direction: column; gap: 4px;
}
.nav-toggle span { display: block; width: 17px; height: 1.8px; background: var(--ink); border-radius: 2px; transition: transform .2s, opacity .2s; }

/* ---------------------------------------------------------------- 首屏 */
.hero {
  position: relative; overflow: hidden;
  background:
    radial-gradient(900px 420px at 82% -12%, rgba(20, 184, 166, 0.18), transparent 62%),
    radial-gradient(680px 380px at 8% 8%, rgba(56, 189, 248, 0.1), transparent 60%),
    linear-gradient(160deg, #0c1626 0%, #0b1220 55%, #0a1019 100%);
  color: #e7eef6;
}
.hero::after {
  content: ""; position: absolute; inset: 0; pointer-events: none;
  background-image: linear-gradient(rgba(148, 163, 184, 0.06) 1px, transparent 1px),
    linear-gradient(90deg, rgba(148, 163, 184, 0.06) 1px, transparent 1px);
  background-size: 56px 56px;
  mask-image: radial-gradient(70% 70% at 30% 20%, #000 20%, transparent 80%);
}
.hero-inner {
  position: relative; z-index: 1;
  display: grid; grid-template-columns: minmax(0, 1.02fr) minmax(0, 0.98fr);
  gap: 48px; align-items: center;
  padding: 68px 0 76px;
}
.eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 12.5px; letter-spacing: .1em; font-weight: 600;
  color: #7dd3c8; text-transform: uppercase;
}
.eyebrow::before { content: ""; width: 22px; height: 1px; background: currentColor; opacity: .7; }
.hero h1 {
  margin: 16px 0 0; font-size: clamp(34px, 4.4vw, 54px); line-height: 1.16;
  letter-spacing: -0.02em; color: #f4f8fb;
}
.hero h1 .accent { color: #5eead4; display: block; }
.hero-desc { margin-top: 18px; max-width: 560px; font-size: 16px; line-height: 1.85; color: #a9bccd; }
.hero-cta { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 28px; }
.hero-chips { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 24px; }
.hero-chips span {
  font-size: 12.5px; color: #b7c8d8; padding: 5px 11px; border-radius: 999px;
  border: 1px solid rgba(148, 163, 184, 0.25); background: rgba(148, 163, 184, 0.08);
}
.hero-media { position: relative; }
.hero-shot-main {
  width: 100%; aspect-ratio: 1 / 1; object-fit: cover;
  border-radius: 22px; border: 1px solid rgba(148, 163, 184, 0.28);
  box-shadow: 0 50px 90px -46px rgba(0, 0, 0, 0.85);
}
.hero-shot-side {
  position: absolute; left: -34px; bottom: -26px;
  width: 44%; aspect-ratio: 1 / 1; object-fit: cover;
  border-radius: 16px; border: 4px solid #0c1626;
  box-shadow: 0 30px 50px -30px rgba(0, 0, 0, 0.9);
}
.hero-badge {
  position: absolute; right: -10px; top: 22px;
  display: grid; gap: 2px; padding: 12px 16px; border-radius: 14px;
  background: rgba(11, 18, 32, 0.78); border: 1px solid rgba(94, 234, 212, 0.3);
  backdrop-filter: blur(10px);
}
.hero-badge strong { font-size: 22px; color: #5eead4; line-height: 1.1; }
.hero-badge span { font-size: 11.5px; color: #a9bccd; letter-spacing: .04em; }

/* ---------------------------------------------------------------- 数字条 */
.stats { position: relative; margin-top: -30px; z-index: 2; padding-bottom: 4px; }
.stats-grid {
  display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 0;
  background: #fff; border: 1px solid var(--line); border-radius: 18px;
  box-shadow: var(--shadow-md); overflow: hidden;
}
.stat { padding: 22px 24px; border-left: 1px solid var(--line-soft); }
.stat:first-child { border-left: 0; }
.stat-num { display: flex; align-items: baseline; gap: 4px; }
.stat-num b { font-size: 30px; line-height: 1; color: var(--ink); letter-spacing: -0.02em; }
.stat-num span { font-size: 13px; color: var(--teal-deep); font-weight: 600; }
.stat-label { margin-top: 4px; font-size: 14.5px; font-weight: 600; color: var(--ink); }
.stat-desc { margin-top: 6px; font-size: 12.5px; color: var(--muted); line-height: 1.6; }

/* ---------------------------------------------------------------- 通用区块 */
.section { padding: 88px 0; }
.section--tight { padding: 64px 0; }
.section--paper { background: var(--paper-2); }
.section--ink { background: var(--ink); color: #dbe6f0; }
.section-head { max-width: 780px; margin-bottom: 40px; }
.section-head h2 { font-size: clamp(26px, 3vw, 36px); color: var(--ink); }
.section-head p { margin-top: 14px; font-size: 16px; color: var(--muted); line-height: 1.85; }
.section--ink .section-head h2 { color: #f2f7fb; }
.section--ink .section-head p { color: #9db0c2; }
.section-head--center { margin-inline: auto; text-align: center; }
.section-head--center .eyebrow { justify-content: center; }
.section-head--center .eyebrow::before { display: none; }
.lead-note { font-size: 13.5px; color: var(--muted-2); margin-top: 12px; }

/* 痛点 / 结果 */
.duo { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 22px; }
.duo-card {
  padding: 28px; border-radius: var(--radius); border: 1px solid var(--line);
  background: #fff; box-shadow: var(--shadow-sm);
}
.duo-card h3 { display: flex; align-items: center; gap: 10px; font-size: 19px; }
.duo-card .dot { width: 9px; height: 9px; border-radius: 50%; flex: 0 0 auto; }
.duo-card--pain { background: linear-gradient(180deg, #fff, #fff6f7); border-color: #f6dfe3; }
.duo-card--pain .dot { background: var(--rose); }
.duo-card--ok { background: linear-gradient(180deg, #fff, var(--teal-wash)); border-color: #d3f0ea; }
.duo-card--ok .dot { background: var(--teal); }
.check-list { list-style: none; margin-top: 16px; display: grid; gap: 11px; }
.check-list li { position: relative; padding-left: 24px; font-size: 14.5px; color: #334355; line-height: 1.7; }
.check-list li::before {
  content: ""; position: absolute; left: 0; top: 7px;
  width: 13px; height: 7px; border-left: 2px solid var(--teal); border-bottom: 2px solid var(--teal);
  transform: rotate(-45deg);
}
.duo-card--pain .check-list li::before {
  width: 12px; height: 2px; border: 0; background: var(--rose); transform: rotate(0);
  top: 12px; border-radius: 2px;
}
.duo-card--pain .check-list li { color: #4a3640; }

/* 全流程 */
.flow-grid { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 18px; }
.flow-card {
  position: relative; display: flex; flex-direction: column;
  border-radius: 16px; overflow: hidden; background: #fff;
  border: 1px solid var(--line); box-shadow: var(--shadow-sm);
  transition: transform .2s, box-shadow .2s, border-color .2s;
}
.flow-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-md); border-color: #cfe3e9; }
.flow-card__media { position: relative; aspect-ratio: 4 / 3; overflow: hidden; }
.flow-card__media img { width: 100%; height: 100%; object-fit: cover; transition: transform .5s ease; }
.flow-card:hover .flow-card__media img { transform: scale(1.04); }
.flow-card__step {
  position: absolute; left: 12px; top: 12px; z-index: 1;
  min-width: 34px; height: 26px; padding: 0 8px; border-radius: 8px;
  display: inline-flex; align-items: center; justify-content: center;
  font-family: var(--mono); font-size: 12px; font-weight: 700; letter-spacing: .04em;
  color: #052e2b; background: rgba(204, 251, 241, 0.94);
  box-shadow: 0 4px 12px -6px rgba(0, 0, 0, 0.5);
}
.flow-card__body { padding: 16px 18px 18px; display: grid; gap: 6px; }
.flow-card__body h3 { font-size: 16.5px; }
.flow-card__sub { font-size: 12px; color: var(--teal-deep); font-weight: 600; letter-spacing: .02em; }
.flow-card__desc { font-size: 13px; color: var(--muted); line-height: 1.7; }
.flow-card__points { display: flex; flex-wrap: wrap; gap: 5px; margin-top: 4px; }
.flow-card__points span {
  font-size: 11.5px; color: #43566a; background: var(--paper-2);
  border: 1px solid var(--line-soft); padding: 2px 7px; border-radius: 6px;
}

/* 硬本事 */
.hard-list { display: grid; gap: 56px; }
.hard {
  display: grid; grid-template-columns: minmax(0, 1.04fr) minmax(0, 0.96fr);
  gap: 44px; align-items: center;
}
.hard:nth-child(even) .hard__media { order: 2; }
.hard__media { position: relative; }
.hard__media img { border-radius: 18px; aspect-ratio: 10 / 7; object-fit: cover; box-shadow: var(--shadow-md); }
.hard__media figcaption {
  position: absolute; left: 14px; bottom: 14px; right: 14px;
  font-size: 12px; color: #e6f4f2; background: rgba(9, 20, 28, 0.66);
  border: 1px solid rgba(148, 163, 184, 0.25);
  padding: 7px 12px; border-radius: 9px; backdrop-filter: blur(8px);
}
.hard__tag {
  display: inline-block; font-family: var(--mono); font-size: 11.5px; letter-spacing: .1em;
  color: var(--teal-deep); background: var(--teal-wash); border: 1px solid #c9ece6;
  padding: 3px 10px; border-radius: 999px;
}
.hard h3 { margin-top: 14px; font-size: clamp(21px, 2.3vw, 27px); }
.hard p.hard__desc { margin-top: 12px; font-size: 15px; color: var(--muted); line-height: 1.85; }
.hard__points { list-style: none; margin-top: 18px; display: grid; gap: 9px; }
.hard__points li { position: relative; padding-left: 20px; font-size: 14px; color: #334355; }
.hard__points li::before {
  content: ""; position: absolute; left: 2px; top: 8px; width: 7px; height: 7px;
  border-radius: 2px; background: var(--teal); transform: rotate(45deg);
}

/* 模块清单 */
.modules { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px; }
.module {
  border: 1px solid var(--line); border-radius: 15px; background: #fff;
  overflow: hidden; box-shadow: var(--shadow-sm);
  transition: border-color .18s, box-shadow .18s;
}
.module[open] { border-color: #b9e3db; box-shadow: var(--shadow-md); }
.module summary {
  list-style: none; cursor: pointer; padding: 18px 20px;
  display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 4px 14px; align-items: center;
}
.module summary::-webkit-details-marker { display: none; }
.module summary:hover { background: #fbfdfe; }
.module__title { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.module__title h3 { font-size: 16.5px; }
.module__count {
  font-family: var(--mono); font-size: 11px; color: var(--teal-deep);
  background: var(--teal-wash); border: 1px solid #cdeee8; border-radius: 999px; padding: 1px 8px;
}
.module__desc { grid-column: 1; font-size: 13px; color: var(--muted); line-height: 1.65; }
.module__roles { grid-column: 1; font-size: 11.5px; color: var(--muted-2); }
.module__more {
  grid-column: 2; grid-row: 1 / span 3; align-self: center;
  font-size: 12px; color: var(--teal-deep); display: inline-flex; align-items: center; gap: 5px;
}
.module__more::after {
  content: ""; width: 6px; height: 6px; border-right: 1.6px solid currentColor;
  border-bottom: 1.6px solid currentColor; transform: rotate(45deg); transition: transform .2s;
}
.module[open] .module__more::after { transform: rotate(225deg); }
.module__body { border-top: 1px solid var(--line-soft); padding: 6px 20px 16px; }
.feature-table { width: 100%; border-collapse: collapse; font-size: 13px; }
.feature-table th, .feature-table td { text-align: left; padding: 8px 8px; border-bottom: 1px dashed var(--line-soft); vertical-align: top; }
.feature-table th { font-size: 11px; color: var(--muted-2); letter-spacing: .08em; font-weight: 600; }
.feature-table td:first-child { font-weight: 600; color: var(--ink); width: 30%; }
.feature-table td:nth-child(2) { color: var(--muted); }
.feature-table td:nth-child(3) { color: var(--muted-2); white-space: nowrap; width: 20%; }
.feature-table tr:last-child td { border-bottom: 0; }
.module__foot { margin-top: 10px; font-size: 12px; color: var(--muted-2); }

/* 角色表 */
.table-wrap { overflow-x: auto; border: 1px solid var(--line); border-radius: 16px; background: #fff; box-shadow: var(--shadow-sm); }
.roles-table { width: 100%; border-collapse: collapse; font-size: 13.5px; min-width: 780px; }
.roles-table th, .roles-table td { padding: 13px 14px; text-align: left; border-bottom: 1px solid var(--line-soft); }
.roles-table thead th { background: var(--paper-2); font-size: 11.5px; letter-spacing: .06em; color: var(--muted); font-weight: 600; }
.roles-table tbody tr:last-child td { border-bottom: 0; }
.roles-table td:first-child { font-weight: 700; color: var(--ink); white-space: nowrap; }
.pill { display: inline-block; font-size: 11.5px; padding: 1px 8px; border-radius: 999px; }
.pill--yes { color: #0b5f59; background: var(--teal-wash); border: 1px solid #c9ece6; }
.pill--no { color: #8b3a4a; background: #fff5f6; border: 1px solid #f4dde1; }
.pill--scope { color: #475569; background: #f1f5f9; border: 1px solid #e2e8f0; }

/* 演示 */
.demo-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 14px; }
.demo-card {
  padding: 16px 18px; border-radius: 14px; border: 1px solid var(--line);
  background: #fff; box-shadow: var(--shadow-sm);
}
.demo-card b { display: block; font-size: 14.5px; color: var(--ink); }
.demo-card code { display: inline-block; margin-top: 6px; font-family: var(--mono); font-size: 13px; color: var(--teal-deep); letter-spacing: .02em; }
.demo-card span { display: block; margin-top: 4px; font-size: 12px; color: var(--muted); }
.demo-note { margin-top: 14px; font-size: 12.5px; color: var(--muted); }
.demo-path { margin-top: 30px; display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px 26px; list-style: none; counter-reset: dp; }
.demo-path li { position: relative; padding-left: 34px; font-size: 13.5px; color: #334355; line-height: 1.75; counter-increment: dp; }
.demo-path li::before {
  content: counter(dp, decimal-leading-zero);
  position: absolute; left: 0; top: 1px; width: 24px; height: 24px; border-radius: 7px;
  display: grid; place-items: center; font-family: var(--mono); font-size: 11px; font-weight: 700;
  color: var(--teal-deep); background: var(--teal-wash); border: 1px solid #cdeee8;
}

/* 实施 */
.impl-grid { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 18px; }
.impl {
  position: relative; padding: 24px 22px; border-radius: 15px;
  background: #fff; border: 1px solid var(--line); box-shadow: var(--shadow-sm);
}
.impl::before {
  content: ""; position: absolute; left: 22px; right: 22px; top: 0; height: 3px;
  border-radius: 0 0 3px 3px; background: linear-gradient(90deg, var(--teal), transparent);
}
.impl b { font-family: var(--mono); font-size: 12px; color: var(--muted-2); letter-spacing: .1em; }
.impl h3 { margin-top: 8px; font-size: 17px; }
.impl p { margin-top: 8px; font-size: 13px; color: var(--muted); line-height: 1.75; }

/* 下载 */
.download-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 18px; }
.download-card {
  display: flex; flex-direction: column; gap: 10px;
  padding: 22px; border-radius: 16px; background: #fff;
  border: 1px solid var(--line); box-shadow: var(--shadow-sm);
  transition: transform .18s, box-shadow .18s, border-color .18s;
}
.download-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); border-color: #c9e6e0; }
.file-icon {
  width: 42px; height: 42px; border-radius: 11px; display: grid; place-items: center;
  font-family: var(--mono); font-size: 11px; font-weight: 700; letter-spacing: .02em;
}
.file-icon--xlsx { background: #ecfdf5; color: #047857; border: 1px solid #bbf7d0; }
.file-icon--pptx { background: #fff7ed; color: #b45309; border: 1px solid #fed7aa; }
.file-icon--docx { background: #eff6ff; color: #1d4ed8; border: 1px solid #bfdbfe; }
.file-icon--txt { background: #f8fafc; color: #475569; border: 1px solid #e2e8f0; }
.download-card h3 { font-size: 16px; }
.download-card p { font-size: 13px; color: var(--muted); line-height: 1.7; }
.download-card .meta { margin-top: auto; display: flex; align-items: center; justify-content: space-between; gap: 10px; font-size: 11.5px; color: var(--muted-2); }
.download-card .meta a { font-weight: 600; font-size: 13px; }

/* FAQ */
.faq { display: grid; gap: 10px; }
.faq details {
  border: 1px solid var(--line); border-radius: 13px; background: #fff;
  padding: 0 20px; box-shadow: var(--shadow-sm);
}
.faq details[open] { border-color: #c4e6df; }
.faq summary {
  list-style: none; cursor: pointer; padding: 16px 30px 16px 0; position: relative;
  font-size: 15px; font-weight: 600; color: var(--ink);
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: "+"; position: absolute; right: 0; top: 13px;
  width: 24px; height: 24px; border-radius: 50%; display: grid; place-items: center;
  font-size: 16px; font-weight: 400; color: var(--teal-deep); background: var(--teal-wash);
  border: 1px solid #cdeee8;
}
.faq details[open] summary::after { content: "−"; }
.faq .answer { padding: 0 0 18px; font-size: 14px; color: var(--muted); line-height: 1.9; }

/* 边界 */
.boundary { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px 28px; list-style: none; }
.boundary li { position: relative; padding-left: 22px; font-size: 13.5px; color: #3d4d5e; line-height: 1.75; }
.boundary li::before {
  content: "—"; position: absolute; left: 0; top: 0; color: var(--muted-2);
}

/* 结尾 CTA */
.cta-band {
  position: relative; overflow: hidden;
  background: linear-gradient(135deg, #0c1a2b 0%, #0b1220 60%, #0a1a18 100%);
  color: #e7eef6; padding: 64px 0;
}
.cta-band::after {
  content: ""; position: absolute; right: -120px; top: -120px; width: 420px; height: 420px;
  border-radius: 50%; background: radial-gradient(circle, rgba(20, 184, 166, 0.22), transparent 65%);
}
.cta-inner { position: relative; z-index: 1; display: flex; align-items: center; justify-content: space-between; gap: 32px; flex-wrap: wrap; }
.cta-inner h2 { font-size: clamp(24px, 3vw, 32px); color: #f4f8fb; max-width: 640px; }
.cta-inner p { margin-top: 10px; color: #9db0c2; font-size: 14.5px; max-width: 640px; }
.cta-actions { display: flex; flex-wrap: wrap; gap: 10px; }

/* ---------------------------------------------------------------- 页脚（对齐 zhubao 布局） */
.site-footer {
  position: relative; z-index: 1; margin-top: 0; padding: 0 0 20px;
  background: linear-gradient(180deg, rgba(8, 12, 20, 0.6) 0%, #05080f 100%);
  color: #b9c8d6; overflow: hidden;
}
.footer-top-line {
  height: 1px;
  background: linear-gradient(90deg, transparent 0%, rgba(20, 184, 166, 0.36) 20%, rgba(94, 234, 212, 0.6) 50%, rgba(20, 184, 166, 0.36) 80%, transparent 100%);
}
.footer-shell { position: relative; padding: 34px 24px 20px; }
.footer-main {
  display: grid; grid-template-columns: minmax(190px, 236px) minmax(0, 1fr) auto;
  gap: 26px 40px; align-items: start; max-width: 1020px; margin: 0 auto;
}
.footer-brand-col { display: flex; flex-direction: column; align-items: flex-start; gap: 10px; }
.footer-logo-link { display: inline-flex; align-items: center; gap: 10px; line-height: 0; }
.footer-logo-link .brand-mark { width: 34px; height: 34px; border-radius: 10px; }
.footer-logo-text { display: flex; flex-direction: column; gap: 2px; line-height: 1.2; }
.footer-logo-text b { font-size: 14.5px; color: #eef6f5; letter-spacing: .01em; }
.footer-logo-text span { font-size: 10.5px; color: #7f93a6; letter-spacing: .1em; }
.footer-slogan { font-size: 12.5px; color: #8fa3b5; line-height: 1.65; margin: 0; max-width: 230px; }
.footer-cta {
  display: inline-flex; align-items: center; margin-top: 2px; padding: 7px 16px;
  border-radius: 999px; font-size: 12.5px; font-weight: 600; color: #04211f; text-decoration: none;
  background: linear-gradient(135deg, #5eead4, #14b8a6); transition: filter .2s, box-shadow .2s;
}
.footer-cta:hover { color: #04211f; filter: brightness(1.06); box-shadow: 0 4px 14px rgba(20, 184, 166, 0.28); }
.footer-nav-grid { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 20px 22px; }
.footer-col h4 { font-size: 11.5px; letter-spacing: .06em; color: #7fe3d3; margin: 0 0 10px; font-weight: 600; }
.footer-col-list { list-style: none; margin: 0; padding: 0; }
.footer-col-list a { display: block; font-size: 12.5px; color: #98abbb; text-decoration: none; padding: 3px 0; line-height: 1.45; transition: color .2s; }
.footer-col-list a:hover { color: #a7f3e8; }
.footer-qr-col { align-self: center; justify-self: end; }
.footer-qr { margin: 0; display: flex; flex-direction: column; align-items: flex-start; gap: 6px; }
.footer-qr img { width: 84px; height: 84px; border-radius: 8px; background: #fff; padding: 3px; object-fit: cover; }
.footer-qr figcaption { max-width: 150px; }
.footer-qr figcaption strong { display: block; font-size: 11.5px; color: #d6e4ee; }
.footer-qr figcaption span { display: block; margin-top: 2px; font-size: 10.5px; color: #7f93a6; line-height: 1.5; }
.footer-trust-bar {
  max-width: 1020px; margin: 0 auto; padding: 16px 24px 12px;
  border-top: 1px solid rgba(255, 255, 255, 0.07); text-align: center;
}
.footer-trust-line, .footer-trust-badges, .footer-trust-meta { max-width: 880px; margin-inline: auto; }
.footer-trust-line { margin: 0 auto 12px; font-size: 12.5px; color: #8fa3b5; line-height: 1.6; }
.footer-trust-line strong { color: #a7f3e8; font-weight: 600; }
.footer-trust-sep { margin: 0 5px; opacity: .35; }
.footer-trust-badges { list-style: none; display: flex; flex-wrap: wrap; justify-content: center; gap: 8px; margin: 0 auto 12px; padding: 0; }
.footer-trust-badges li {
  font-size: 11.5px; color: #6fe0cf; background: rgba(20, 184, 166, 0.08);
  border: 1px solid rgba(20, 184, 166, 0.22); padding: 4px 10px; border-radius: 999px; white-space: nowrap;
}
.footer-trust-meta { margin: 0 auto; font-size: 12.5px; color: #8fa3b5; line-height: 1.7; }
.footer-trust-meta a { color: #8fa3b5; text-decoration: none; }
.footer-trust-meta a:hover { color: #a7f3e8; }
.footer-bottom {
  max-width: 1020px; margin: 0 auto; padding: 12px 24px 16px;
  border-top: 1px solid rgba(255, 255, 255, 0.06); text-align: center;
}
.footer-bottom-links { display: flex; flex-wrap: wrap; justify-content: center; gap: 6px 14px; margin-bottom: 8px; }
.footer-bottom-links a { font-size: 11.5px; color: #8fa3b5; text-decoration: none; transition: color .2s; }
.footer-bottom-links a:hover { color: #a7f3e8; }
.footer-copyright { margin: 0; font-size: 11.5px; color: #7f93a6; line-height: 1.6; }

/* 手机底部快捷条 */
.mobile-contact-bar {
  display: none; position: fixed; left: 0; right: 0; bottom: 0; z-index: 70;
  padding: 8px 12px calc(8px + env(safe-area-inset-bottom, 0px));
  background: rgba(9, 14, 22, 0.94); border-top: 1px solid rgba(148, 163, 184, 0.2);
  backdrop-filter: blur(12px); gap: 8px;
}
.mobile-contact-bar a {
  flex: 1; display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  min-height: 42px; border-radius: 11px; font-size: 13px; color: #dbe6f0;
  background: rgba(255, 255, 255, 0.06); border: 1px solid rgba(255, 255, 255, 0.1);
}
.mobile-contact-bar a.is-cta { background: var(--teal-deep); border-color: var(--teal-deep); color: #fff; font-weight: 600; }

/* ---------------------------------------------------------------- 响应式 */
@media (max-width: 1080px) {
  .hero-inner { gap: 34px; padding: 56px 0 66px; }
  .hero-shot-side { left: -20px; bottom: -18px; }
  .footer-nav-grid { grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 18px 14px; }
  .flow-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .impl-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 960px) {
  .nav-toggle { display: inline-flex; }
  .nav--site {
    position: fixed; inset: 72px 0 auto; z-index: 75;
    background: #fff; border-bottom: 1px solid var(--line);
    max-height: calc(100dvh - 72px); overflow-y: auto;
    padding: 8px 16px 24px; display: none;
    box-shadow: 0 24px 40px -30px rgba(11, 18, 32, 0.5);
  }
  body.nav-open .nav--site { display: block; }
  body.nav-open { overflow: hidden; }
  .nav-list { flex-direction: column; align-items: stretch; gap: 2px; }
  .nav-link { justify-content: space-between; padding: 14px 12px; font-size: 15px; border-radius: 10px; }
  .nav-panel {
    position: static; width: auto; max-width: none; transform: none;
    opacity: 1; visibility: visible; pointer-events: auto; display: none;
    padding: 0 0 8px;
  }
  .nav-item.is-open > .nav-panel { display: block; transform: none; }
  .nav-panel__card { grid-template-columns: 1fr; gap: 8px; padding: 8px; box-shadow: none; border-color: var(--line-soft); }
  .nav-panel__links, .nav-panel__links--3 { grid-template-columns: 1fr; }
  .nav-panel__feature { display: none; }
  .header-actions .btn--ghost { display: none; }
  .hero-inner { grid-template-columns: 1fr; gap: 30px; padding-top: 46px; }
  .hero-media { max-width: 520px; margin: 0 auto 12px; width: 100%; }
  .hero-desc { max-width: none; }
  .stats { margin-top: -22px; }
  .stats-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .stat:nth-child(3) { border-left: 0; }
  .stat { border-top: 1px solid var(--line-soft); }
  .stat:nth-child(-n+2) { border-top: 0; }
  .hard { grid-template-columns: 1fr; gap: 22px; }
  .hard:nth-child(even) .hard__media { order: 0; }
  .hard-list { gap: 44px; }
  .modules { grid-template-columns: 1fr; }
  .download-grid { grid-template-columns: 1fr; }
  .demo-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .duo { grid-template-columns: 1fr; }
  .footer-main { grid-template-columns: 1fr; gap: 24px; }
  .footer-brand-col { align-items: flex-start; }
  .footer-qr-col { justify-self: start; }
  .footer-nav-grid { grid-template-columns: repeat(4, minmax(0, 1fr)); padding-top: 20px; border-top: 1px solid rgba(255,255,255,.06); }
  .mobile-contact-bar { display: flex; }
  body { padding-bottom: 68px; }
  .section { padding: 68px 0; }
}

@media (max-width: 720px) {
  .container, .container--narrow { width: calc(100% - 32px); }
  .header-inner { min-height: 64px; gap: 10px; }
  .nav--site { inset: 64px 0 auto; max-height: calc(100dvh - 64px); }
  .brand-name { font-size: 14px; }
  .brand-sub { font-size: 10px; letter-spacing: .05em; }
  .brand-mark { width: 34px; height: 34px; border-radius: 10px; }
  .header-actions .btn { padding: 8px 13px; font-size: 13px; }
  .hero-inner { padding: 36px 0 56px; }
  .hero h1 { font-size: 32px; }
  .hero-desc { font-size: 14.5px; }
  .hero-shot-side { width: 40%; left: -8px; bottom: -14px; border-width: 3px; }
  .hero-badge { right: 0; top: 12px; padding: 9px 12px; }
  .hero-badge strong { font-size: 18px; }
  .stats-grid { border-radius: 14px; }
  .stat { padding: 16px 16px; }
  .stat-num b { font-size: 24px; }
  .stat-desc { font-size: 11.5px; }
  .flow-grid { grid-template-columns: 1fr; }
  .impl-grid { grid-template-columns: 1fr; }
  .demo-grid { grid-template-columns: 1fr; }
  .demo-path { grid-template-columns: 1fr; }
  .boundary { grid-template-columns: 1fr; }
  .feature-table td:first-child { width: 38%; }
  .feature-table td:nth-child(3) { display: none; }
  .feature-table th:nth-child(3) { display: none; }
  .footer-nav-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px 12px; }
  .footer-trust-meta span, .footer-trust-meta a { display: block; }
  .footer-trust-sep { display: none; }
  .footer-shell { padding: 22px 16px 14px; }
  .footer-trust-bar { padding: 12px 16px; }
  .footer-qr img { width: 76px; height: 76px; }
  .cta-inner { align-items: flex-start; }
  .section-head { margin-bottom: 28px; }
}

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

/* 下载中心页 */
.page-head {
  padding: 46px 0 34px;
  background:
    radial-gradient(680px 280px at 88% -30%, rgba(20, 184, 166, 0.16), transparent 60%),
    linear-gradient(160deg, #0c1626, #0b1220);
  color: #e7eef6;
}
.page-head .breadcrumb { font-size: 12px; color: #8fa3b5; display: flex; gap: 6px; flex-wrap: wrap; }
.page-head .breadcrumb a { color: #9fb3c4; }
.page-head h1 { margin-top: 12px; font-size: clamp(26px, 3.4vw, 38px); }
.page-head p { margin-top: 12px; max-width: 720px; font-size: 14.5px; color: #a9bccd; line-height: 1.85; }
.dl-list { display: grid; gap: 12px; }
.dl-row {
  display: grid; grid-template-columns: 56px minmax(0, 1fr) auto;
  gap: 18px; align-items: center; padding: 20px 22px;
  background: #fff; border: 1px solid var(--line); border-radius: 15px;
  box-shadow: var(--shadow-sm); transition: border-color .18s, box-shadow .18s;
}
.dl-row:hover { border-color: #c9e6e0; box-shadow: var(--shadow-md); }
.dl-row .file-icon { width: 48px; height: 48px; font-size: 12px; }
.dl-row h3 { font-size: 16.5px; }
.dl-row p { margin-top: 4px; font-size: 13px; color: var(--muted); line-height: 1.7; }
.dl-row .dl-meta { margin-top: 6px; font-size: 11.5px; color: var(--muted-2); display: flex; gap: 12px; flex-wrap: wrap; }
.dl-row .btn { align-self: center; }
.facts { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 14px; margin-top: 22px; }
.fact { padding: 18px 20px; border-radius: 13px; background: var(--paper-2); border: 1px solid var(--line-soft); }
.fact b { display: block; font-size: 20px; color: var(--ink); }
.fact span { font-size: 12.5px; color: var(--muted); }
@media (max-width: 720px) {
  .dl-row { grid-template-columns: 44px minmax(0, 1fr); gap: 12px; padding: 16px; }
  .dl-row .file-icon { width: 40px; height: 40px; font-size: 11px; }
  .dl-row .btn { grid-column: 1 / -1; justify-self: start; }
  .facts { grid-template-columns: 1fr; }
}