:root{--ink:#414938;--muted:#6d7566;--paper:#f7f6ef;--sage:#64774e;--border:#dde1d2;--card:#fffef9}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:90px}body{margin:0;background:var(--paper);color:var(--ink);font:16px/1.7 system-ui,sans-serif}a{color:var(--sage);text-underline-offset:4px}header{position:sticky;top:0;z-index:2;display:flex;align-items:center;justify-content:space-between;gap:15px;padding:16px max(24px,calc((100vw - 1200px)/2));background:var(--paper);border-bottom:1px solid var(--border)}.brand{font:600 22px Georgia,serif;text-decoration:none;white-space:nowrap}.back{font-size:13px;border:1px solid var(--border);padding:7px 13px;border-radius:8px;text-decoration:none;white-space:nowrap}.layout{max-width:1200px;display:grid;grid-template-columns:235px minmax(0,1fr);gap:60px;margin:auto;padding:38px 24px}.layout>aside{position:sticky;top:106px;align-self:start}.eyebrow,.section-label{font-size:11px;letter-spacing:1.4px;color:var(--sage);font-weight:700}.layout nav{display:flex;flex-direction:column;gap:5px;margin-top:15px}.layout nav a{text-decoration:none;padding:8px 12px;border-radius:7px;font-size:14px}.layout nav a:hover,.layout nav a:focus-visible{background:#e8eddf}.side-note{font-size:12px;color:var(--muted);padding:14px 12px;margin-top:18px;border-top:1px solid var(--border)}.intro{padding:0 0 25px}.intro h1{font:normal 44px/1.14 Georgia,serif;letter-spacing:-.6px;margin:14px 0 18px}.intro p{font-size:17px;max-width:650px;color:var(--muted)}section{padding:30px 0;border-top:1px solid var(--border);scroll-margin-top:5px}h2{font:600 27px/1.25 Georgia,serif;margin:8px 0 18px}h3{font-size:16px;margin:0 0 12px}p{margin:12px 0}ol,ul{padding-left:24px}li{padding-left:5px;margin:12px 0}strong,b{font-weight:650}.quickstart{list-style:none;counter-reset:steps;padding:0;display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px}.quickstart li{counter-increment:steps;background:var(--card);border:1px solid var(--border);border-radius:12px;padding:17px;margin:0;font-size:13px;line-height:1.65}.quickstart li:before{content:counter(steps);display:block;width:28px;height:28px;text-align:center;line-height:28px;background:#e8eedf;color:var(--sage);border-radius:50%;font-weight:700;margin-bottom:12px}.quickstart b{display:block;font-size:15px;margin-bottom:8px}.tips,.callout{background:#eaf0e1;border-radius:12px;padding:16px 20px;margin:20px 0;font-size:14px}.tips p:first-child,.callout p:first-child{margin-top:0}.tips p:last-child,.callout p:last-child{margin-bottom:0}.lesson-grid,.storage-grid{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin:20px 0}.lesson-grid>div,.storage-grid article{background:var(--card);border:1px solid var(--border);border-radius:12px;padding:18px;font-size:14px}.lesson-grid p{margin-bottom:0}.storage-grid li{margin:7px 0}.storage-grid article.download-note{background:#f6ecd8;border-color:#e9daba}.muted{color:var(--muted);font-size:14px}details{border:1px solid var(--border);border-radius:9px;background:var(--card);margin:10px 0;padding:12px 16px}summary{cursor:pointer;font-size:15px;font-weight:600;min-height:30px}details p{font-size:14px;margin:10px 0 4px}footer{padding:24px 0;color:var(--muted);font-size:13px;border-top:1px solid var(--border)}a:focus-visible,summary:focus-visible{outline:3px solid #91a57c;outline-offset:3px}.skip{position:fixed;top:-60px;left:10px;z-index:5;background:white;padding:10px}.skip:focus{top:10px}@media(max-width:900px){.layout{gap:28px;grid-template-columns:190px minmax(0,1fr)}.quickstart{grid-template-columns:1fr}.quickstart li{position:relative;padding-left:60px}.quickstart li:before{position:absolute;left:17px;top:17px}.intro h1{font-size:37px}}@media(max-width:650px){header{padding:12px 14px}.brand{font-size:17px}.back{font-size:11px;padding:6px 8px}.layout{display:block;padding:22px 18px}.layout>aside{position:static;border-bottom:1px solid var(--border);padding-bottom:20px;margin-bottom:25px}.layout nav{display:grid;grid-template-columns:1fr 1fr;gap:4px;margin-top:10px}.layout nav a{font-size:12px;background:#edf0e6;padding:9px}.side-note{display:none}.intro h1{font-size:34px}.intro p{font-size:15px}body{font-size:15px}section{padding:24px 0}h2{font-size:24px}.lesson-grid,.storage-grid{grid-template-columns:1fr}.quickstart li{font-size:13px}.tips,.callout{padding:14px}html{scroll-padding-top:78px}}@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}}@media print{header,.layout>aside,.skip{display:none}.layout{display:block;padding:0}body{background:white;font-size:11pt}section{break-inside:avoid}details{display:block}details>p{display:block}}

/* iOS PWA: opaque header color sample; see ../IOS-PWA-BLUR.md. */
html{background:var(--paper)}
.ios-status-color{display:none}
@media (display-mode:standalone){
  /* Keep content inside the device safe area when viewport-fit=cover is used. */
  body{padding:0 env(safe-area-inset-right,0px) env(safe-area-inset-bottom,0px) env(safe-area-inset-left,0px)}
  .ios-status-color{display:block;position:fixed;top:0;left:0;width:100%;height:1px;background-color:var(--paper);z-index:2147483647;pointer-events:none}
}

/* Safe area belongs to the sticky header, as in the reference app. */
@media (display-mode:standalone){
  body>header{top:0;padding-top:calc(16px + env(safe-area-inset-top,0px))}
  body>header::before{content:"";position:fixed;inset:0 0 auto;height:env(safe-area-inset-top,0px);background:var(--paper);pointer-events:none}
}