:root {
  --ink: #15181b;
  --muted: #5a646b;
  --paper: #f5f7f4;
  --panel: #ffffff;
  --line: #d9dfd9;
  --accent: #2f776a;
  --accent-dark: #174f48;
  --warm: #b56d2b;
  --amber: #f0b653;
  --shadow: 0 18px 50px rgba(21, 24, 27, 0.12);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  font-family: "Aptos", "Microsoft YaHei UI", "Noto Sans SC", Arial, sans-serif;
  background: linear-gradient(180deg, #eef3ef 0%, #f8f6f0 48%, #eef2f1 100%);
}
body.radiusrunner { --accent: #c56f27; --accent-dark: #744019; --warm: #145c73; --amber: #ffd27a; }
body.viewtrail { --accent: #3f6f9c; --accent-dark: #203f5f; --warm: #927037; --amber: #f5cf7a; }
body.mass-distrib { --accent: #496f62; --accent-dark: #243f37; --warm: #a36e32; --amber: #f1c36e; }

a { color: inherit; text-decoration: none; }
.topbar, main, footer { width: min(1120px, calc(100% - 32px)); margin: 0 auto; }
.topbar { display: flex; align-items: center; justify-content: space-between; gap: 22px; padding: 18px 0; }
.brand { display: inline-flex; align-items: center; gap: 12px; min-width: 180px; }
.brand img { width: 42px; height: 42px; object-fit: contain; }
.brand strong, .brand small { display: block; line-height: 1.1; }
.brand strong { font-size: 20px; font-weight: 900; }
.brand small { color: var(--muted); font-size: 12px; }
nav { display: flex; align-items: center; gap: 6px; }
nav a { padding: 9px 12px; border-radius: 999px; color: #2d373b; font-size: 14px; font-weight: 700; }
nav a:hover { background: color-mix(in srgb, var(--accent) 12%, transparent); color: var(--accent-dark); }

.hero { display: grid; grid-template-columns: minmax(0, 1fr) minmax(360px, .82fr); gap: 44px; align-items: center; padding: 52px 0 46px; }
.eyebrow { margin: 0 0 12px; color: var(--warm); font-size: 13px; font-weight: 900; }
h1, h2, h3, p { margin-top: 0; }
h1 { margin-bottom: 20px; font-size: clamp(46px, 6vw, 64px); line-height: 1; }
h2 { margin-bottom: 14px; font-size: 36px; line-height: 1.15; }
h3 { margin-bottom: 10px; font-size: 20px; }
.lead, .section-heading p, .grid p, .download-panel p, .steps span { color: var(--muted); font-size: 17px; line-height: 1.75; }
.actions { display: flex; flex-wrap: wrap; gap: 12px; margin: 28px 0 22px; }
.button { display: inline-flex; align-items: center; justify-content: center; min-height: 46px; padding: 0 20px; border: 1px solid var(--line); border-radius: 999px; font-weight: 900; transition: transform .18s ease, box-shadow .18s ease; }
.button:hover { transform: translateY(-1px); box-shadow: 0 12px 30px rgba(21, 24, 27, .14); }
.button.primary { color: #fff; border-color: var(--accent-dark); background: linear-gradient(135deg, var(--accent-dark), var(--accent)); }
.button.secondary { background: rgba(255,255,255,.7); }
.facts { display: flex; flex-wrap: wrap; gap: 10px; margin: 0; padding: 0; list-style: none; }
.facts li { padding: 8px 12px; border: 1px solid color-mix(in srgb, var(--accent) 25%, transparent); border-radius: 999px; color: var(--accent-dark); background: rgba(255,255,255,.62); font-size: 13px; font-weight: 800; }

.hero-visual { padding: 18px; border: 1px solid rgba(255,255,255,.8); border-radius: 8px; background: #202629; box-shadow: var(--shadow); }
.visual-stage { position: relative; min-height: 360px; overflow: hidden; border-radius: 8px; background: linear-gradient(160deg, rgba(255,255,255,.16), transparent 34%), repeating-linear-gradient(170deg, rgba(255,255,255,.07) 0 2px, transparent 2px 28px), linear-gradient(135deg, var(--accent), #11181b); }
.visual-stage::before { content: ""; position: absolute; inset: 62px 12% 76px; border: 2px solid rgba(255,255,255,.58); border-radius: 28px 76px 34px 66px; transform: rotate(-8deg); box-shadow: inset 0 0 40px rgba(255,255,255,.08); }
.visual-stage::after { content: ""; position: absolute; left: 14%; right: 14%; bottom: 96px; height: 7px; border-radius: 999px; background: linear-gradient(90deg, transparent, var(--amber), transparent); transform: rotate(-8deg); }
.visual-mark { position: absolute; left: 50%; top: 50%; width: 120px; height: 120px; transform: translate(-50%, -50%); object-fit: contain; filter: drop-shadow(0 14px 28px rgba(0,0,0,.3)); }
.visual-label { position: absolute; right: 24px; bottom: 24px; padding: 9px 12px; border: 1px solid rgba(255,255,255,.24); border-radius: 999px; color: #fff; background: rgba(21,24,27,.48); font-size: 12px; font-weight: 900; letter-spacing: .08em; }
.visual-caption { display: flex; align-items: center; gap: 10px; padding-top: 14px; color: rgba(255,255,255,.76); font-size: 13px; font-weight: 800; }
.visual-caption img { width: 28px; height: 28px; object-fit: contain; }

.section { padding: 58px 0; }
.section-heading { max-width: 760px; margin-bottom: 24px; }
.grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 16px; }
.grid article { min-height: 210px; padding: 24px; border: 1px solid var(--line); border-radius: 8px; background: rgba(255,255,255,.72); box-shadow: 0 12px 36px rgba(21,24,27,.06); }
.download-panel { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 28px; align-items: center; padding: 30px; border: 1px solid color-mix(in srgb, var(--accent) 28%, transparent); border-radius: 8px; color: #fff; background: linear-gradient(135deg, #15181b, var(--accent-dark)); box-shadow: var(--shadow); }
.download-panel p { color: rgba(255,255,255,.72); }
.download-panel .eyebrow { color: var(--amber); }
.hash { margin: 16px 0 0; overflow-wrap: anywhere; font-size: 13px !important; }
.hash span { color: rgba(255,255,255,.88); font-family: Consolas, "Courier New", monospace; }
.notice { margin: 14px 0 0; padding: 12px 14px; border: 1px solid rgba(240,182,83,.42); border-radius: 8px; background: rgba(240,182,83,.1); font-size: 14px !important; }
.steps { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 16px; margin: 0; padding: 0; list-style: none; counter-reset: steps; }
.steps li { counter-increment: steps; padding: 24px; border: 1px solid var(--line); border-radius: 8px; background: rgba(255,255,255,.72); }
.steps li::before { content: "0" counter(steps); display: block; margin-bottom: 28px; color: var(--warm); font-size: 28px; font-weight: 900; }
.steps strong, .steps span { display: block; }
.steps strong { margin-bottom: 8px; font-size: 20px; }

footer { display: flex; flex-direction: column; align-items: center; gap: 14px; padding: 34px 0 44px; color: var(--muted); font-size: 14px; text-align: center; }
footer strong, footer span { display: block; }
footer strong { color: var(--ink); }
.footer-legal { display: flex; flex-direction: column; align-items: center; gap: 8px; }
.footer-legal p { margin: 0; }
.beian-links { display: flex; align-items: center; justify-content: center; flex-wrap: wrap; gap: 8px 18px; }
.police-beian { display: inline-flex; align-items: center; gap: 6px; }
.police-beian img { width: 20px; height: 20px; object-fit: contain; flex: 0 0 auto; }

@media (max-width: 860px) {
  .topbar { align-items: flex-start; flex-direction: column; }
  nav { flex-wrap: wrap; }
  .hero, .download-panel, .grid, .steps { grid-template-columns: 1fr; }
  h2 { font-size: 30px; }
  .hero { padding-top: 28px; }
  .download-panel .button { justify-self: start; }
}
@media (max-width: 520px) {
  .topbar, main, footer { width: min(100% - 24px, 1120px); }
  h1 { font-size: 40px; }
  .actions { align-items: stretch; flex-direction: column; }
  .button { width: 100%; }
  .visual-stage { min-height: 280px; }
  footer { align-items: flex-start; text-align: left; }
  .footer-legal { align-items: flex-start; }
  .beian-links { justify-content: flex-start; }
}