:root {
  --ink: #1f2428;
  --paper: #fafbfc;
  --plate: #eceff1;
  --muted: #6a737b;
  --line: #d0d7de;
  --accent: #24292f;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: "IBM Plex Sans", "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--ink);
  background: var(--paper);
  line-height: 1.65;
}
a { color: inherit; text-decoration: none; }
img { max-width:100%;height:auto; display: block; }
.wrap { width: min(1040px, calc(100% - 36px)); margin: 0 auto; }
nav {
  position: sticky; top: 0; z-index: 20;
  background: rgba(250, 251, 252, .94);
  border-bottom: 1px solid var(--line);
}
.nav { display: flex; align-items: center; gap: 20px; min-height: 64px; }
.brand { font-weight: 700; letter-spacing: .08em; font-size: 14px; }
.links { display: flex; gap: 18px; margin-left: auto; font-size: 13px; color: var(--muted); }
.button {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 9px 16px; background: var(--accent); color: #fff; border: 0; font-size: 13px; font-weight: 700;
}
.ghost { display: inline-flex; border-bottom: 1px solid var(--ink); padding-bottom: 2px; font-size: 13px; }
.hero { padding: 52px 0 0; }
.kicker { font-size: 11px; letter-spacing: .22em; text-transform: uppercase; color: var(--muted); margin-bottom: 12px; }
h1 { font-size: clamp(28px, 4vw, 42px); font-weight: 650; line-height: 1.2; margin-bottom: 12px; }
.lead { font-size: 17px; margin-bottom: 8px; }
.actions { display: flex; gap: 14px; align-items: center; margin: 22px 0 28px; }
.hero img { width: 100%; height: 280px; object-fit: cover; }
.define { background: var(--plate); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); margin-top: 0; }
.plate {
  display: grid; grid-template-columns: 64px 1fr; gap: 16px; align-items: center;
  min-height: 64px; padding: 14px 0;
  font-size: 14px;
}
.plate span {
  font-size: 11px; letter-spacing: .2em; color: var(--muted); font-weight: 700;
}
.plate p { margin: 0; letter-spacing: .02em; }
.section { padding: 64px 0; }
.head { max-width: 580px; margin-bottom: 24px; }
h2 { font-size: 24px; font-weight: 650; margin-bottom: 8px; }
.grid6 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.card { padding-top: 12px; border-top: 1px solid var(--line); }
.icon { font-size: 11px; letter-spacing: .16em; color: var(--muted); margin-bottom: 6px; }
.split { display: grid; grid-template-columns: 1fr 1fr; gap: 32px; align-items: center; }
.split img, .shot img { width: 100%; height: 300px; object-fit: cover; }
.scene-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 8px 14px; margin: 14px 0 20px; }
.scene { display: flex; gap: 8px; padding: 8px 0; border-bottom: 1px solid var(--line); font-size: 14px; }
.review-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.review { padding-top: 12px; border-top: 1px solid var(--line); }
.person { margin-top: 10px; display: flex; flex-direction: column; font-size: 13px; }
.person small { color: var(--muted); }
.visual { padding: 0 0 64px; }
.metrics { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; margin: 16px 0 20px; }
.metrics div { padding-top: 8px; border-top: 1px solid var(--line); }
.metrics b { display: block; font-size: 20px; }
.faq-layout { display: grid; grid-template-columns: .75fr 1.25fr; gap: 32px; }
details { padding: 12px 0; border-bottom: 1px solid var(--line); }
summary { cursor: pointer; font-weight: 700; }
details p { margin-top: 8px; color: var(--muted); }
.cta { padding: 44px 0; background: var(--plate); }
.cta-in { display: flex; justify-content: space-between; align-items: center; gap: 16px; }
footer { padding: 36px 0 18px; border-top: 1px solid var(--line); }
.footer { display: grid; grid-template-columns: 1.4fr 1fr 1fr 1fr; gap: 16px; }
.footer h4 { margin-bottom: 8px; font-size: 12px; letter-spacing: .1em; }
.footer a, .footer p { display: block; color: var(--muted); font-size: 13px; margin-top: 6px; }
.copy { margin-top: 16px; font-size: 12px; color: var(--muted); }
.page-head { padding: 48px 0 8px; }
.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; }
.download-card { padding-top: 16px; border-top: 2px solid var(--accent); }
.help-layout { display: grid; grid-template-columns: 190px 1fr; gap: 28px; }
.side { position: sticky; top: 80px; align-self: start; }
.side a { display: block; padding: 8px 0; border-bottom: 1px solid var(--line); font-size: 13px; }
.article { padding: 8px 0 24px; }
.policy { margin-top: 14px; padding-top: 10px; color: var(--muted); }
@media (max-width: 900px) {
  .links { display: none; }
  .split, .faq-layout, .help-layout, .cta-in, .cards, .footer { grid-template-columns: 1fr; }
  .grid6, .review-grid { grid-template-columns: 1fr 1fr; }
  .hero img, .split img, .shot img { height: 210px; }
  .plate { grid-template-columns: 1fr; }
}
@media (max-width: 560px) {
  .grid6, .review-grid, .metrics { grid-template-columns: 1fr; }
}

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