:root{
  --ink:#171717;
  --muted:#6f6f6b;
  --soft:#f7f7f5;
  --line:#e7e7e2;
  --max:700px;
  --serif:"Source Serif 4",Georgia,"Times New Roman",serif;
  --ui:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;
}
*{box-sizing:border-box}
html{background:#fff;color:var(--ink)}
body{margin:0;background:#fff;color:var(--ink);font-family:var(--ui);-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
a{color:inherit}
.shell{width:min(var(--max),calc(100% - 36px));margin:0 auto;padding:0 0 42px}
.topbar{height:58px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line);font-size:13px}
.topbar a{text-decoration:none}
.topbar .back{font-weight:650}
.topbar .brand{color:var(--muted);font-weight:600}
main{padding-top:0}

/* app chooser */
.chooser{padding:46px 0 22px;text-align:center}
.app-icon{display:block;width:76px;height:76px;margin:0 auto 18px;border-radius:18px;box-shadow:0 7px 18px rgba(0,0,0,.11)}
.kicker{margin:0 0 8px;color:var(--muted);font-size:12px;font-weight:700;letter-spacing:.08em;text-transform:uppercase}
h1{margin:0;font-family:var(--serif);font-size:38px;line-height:1.05;font-weight:400;letter-spacing:-.025em}
.chooser .intro{max-width:470px;margin:12px auto 0;color:var(--muted);font-size:15px;line-height:1.55}
.platform-list{margin-top:22px;border-top:1px solid var(--line)}
.platform-row{min-height:82px;display:grid;grid-template-columns:1fr auto;gap:18px;align-items:center;padding:15px 2px;border-bottom:1px solid var(--line);text-decoration:none}
.platform-row:hover .arrow,.platform-row:focus-visible .arrow{transform:translateX(3px)}
.platform-row h2{margin:0;font-family:var(--serif);font-size:23px;line-height:1.15;font-weight:400}
.platform-row p{margin:5px 0 0;color:var(--muted);font-size:12.5px;line-height:1.4}
.platform-row .arrow{font-size:24px;font-weight:300;color:#797976;transition:transform .15s ease}
.web-link{padding:21px 0 0;text-align:center;color:var(--muted);font-size:12.5px}
.web-link a{text-underline-offset:3px}

/* detail */
.detail-hero{padding:42px 0 26px;text-align:center}
.detail-hero .app-icon{width:88px;height:88px;border-radius:21px;margin-bottom:18px}
.detail-hero h1{font-size:40px}
.detail-hero .lead{max-width:520px;margin:12px auto 0;color:var(--muted);font-size:15px;line-height:1.55}
.primary-action{display:inline-flex;align-items:center;justify-content:center;min-height:48px;margin-top:22px;padding:0 22px;border-radius:10px;background:#171717;color:#fff;text-decoration:none;font-size:13px;font-weight:750;letter-spacing:.005em}
.primary-action:hover{background:#000}
.meta{margin:11px 0 0;color:#858581;font-size:11.5px;line-height:1.4}
.simple-section{border-top:1px solid var(--line);padding:25px 0}
.simple-section h2{margin:0 0 14px;font-family:var(--serif);font-size:25px;line-height:1.15;font-weight:400}
.simple-list{list-style:none;margin:0;padding:0}
.simple-list li{display:grid;grid-template-columns:22px 1fr;gap:10px;padding:10px 0;color:#31312f;font-size:13.5px;line-height:1.5}
.simple-list li::before{content:"✓";color:#777772;font-weight:700}
.copy{margin:0;color:var(--muted);font-size:13.5px;line-height:1.6}
.steps{list-style:none;counter-reset:step;margin:0;padding:0}
.steps li{counter-increment:step;display:grid;grid-template-columns:28px 1fr;gap:12px;padding:11px 0;border-bottom:1px solid var(--line);font-size:13.5px;line-height:1.5}
.steps li:last-child{border-bottom:0}
.steps li::before{content:counter(step);width:24px;height:24px;border:1px solid #cfcfca;border-radius:50%;display:flex;align-items:center;justify-content:center;color:#666661;font-size:11px;font-weight:700}
.notice{margin:16px 0 0;padding:14px 15px;background:var(--soft);border-radius:10px;color:#595954;font-size:12px;line-height:1.55}
.other-apps{padding:19px 0 0;border-top:1px solid var(--line);text-align:center;font-size:12.5px;color:var(--muted)}
.other-apps a{text-underline-offset:3px}
footer{margin-top:34px;color:#9a9a95;font-size:10.5px;text-align:center}

@media(max-width:600px){
  .shell{width:min(var(--max),calc(100% - 28px));padding-bottom:30px}
  .topbar{height:52px;font-size:12px}
  .chooser{padding:32px 0 15px}
  .app-icon{width:68px;height:68px;border-radius:16px;margin-bottom:15px}
  h1{font-size:32px}
  .chooser .intro{margin-top:9px;font-size:13.5px;line-height:1.5}
  .platform-list{margin-top:17px}
  .platform-row{min-height:76px;padding:13px 2px}
  .platform-row h2{font-size:21px}
  .platform-row p{font-size:12px}
  .detail-hero{padding:31px 0 22px}
  .detail-hero .app-icon{width:76px;height:76px;border-radius:18px;margin-bottom:15px}
  .detail-hero h1{font-size:33px}
  .detail-hero .lead{font-size:13.5px;line-height:1.52}
  .primary-action{width:100%;min-height:50px;margin-top:19px}
  .simple-section{padding:22px 0}
  .simple-section h2{font-size:23px}
  .simple-list li,.steps li,.copy{font-size:13px}
}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important}}