/* The product page (/about): the app's colours and type (styles.css), light or dark like the app (html[data-theme], public/theme.js),
   both languages in the page and one shown (html[data-lang]). */
:root {
  /* light: white with a faint cool tint, like the app (styles.css); dark: the navy board */
  --board: #ffffff;
  --board-2: #eef2f7;
  --board-ink: #0f131a;
  --board-muted: #4b5261;
  --board-line: #e1e5eb;
  --board-accent: #9a5700;
  --glass: 20, 24, 33;
  --hero-shadow: 0 24px 60px rgba(20, 24, 33, 0.16);
  --amber: #f5b544;
  --bg: #f3f5f8;
  --surface: #ffffff;
  --ink: #0f131a;
  --muted: #4b5261;
  --line: #e1e5eb;
  --accent: #0f766e;
  --focus: #2f6fed;
  --shadow: 0 1px 2px rgba(20, 24, 33, 0.06), 0 12px 32px rgba(20, 24, 33, 0.1);
  --display: "Space Grotesk", "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color-scheme: light;
}
/* dark: follows the system unless the visitor picked light; the copy after it is their own pick */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) { --board: #0a111e; --board-2: #121c30; --board-ink: #f3efe6; --board-muted: #b9c0cc; --board-line: rgba(255, 255, 255, 0.12); --board-accent: #f5b544; --glass: 255, 255, 255; --hero-shadow: 0 30px 80px rgba(0, 0, 0, 0.45); --bg: #0d1119; --surface: #151b27; --ink: #ece9e2; --muted: #98a0ad; --line: #262e3d; --accent: #4fc3b5; --focus: #7aa2ff; --shadow: 0 1px 2px rgba(0, 0, 0, 0.35), 0 12px 32px rgba(0, 0, 0, 0.35); color-scheme: dark; }
}
:root[data-theme="dark"] { --board: #0a111e; --board-2: #121c30; --board-ink: #f3efe6; --board-muted: #b9c0cc; --board-line: rgba(255, 255, 255, 0.12); --board-accent: #f5b544; --glass: 255, 255, 255; --hero-shadow: 0 30px 80px rgba(0, 0, 0, 0.45); --bg: #0d1119; --surface: #151b27; --ink: #ece9e2; --muted: #98a0ad; --line: #262e3d; --accent: #4fc3b5; --focus: #7aa2ff; --shadow: 0 1px 2px rgba(0, 0, 0, 0.35), 0 12px 32px rgba(0, 0, 0, 0.35); color-scheme: dark; }

/* one language at a time */
html[data-lang="zh"] .l-en, html:not([data-lang="zh"]) .l-zh { display: none !important; }
:lang(zh) h1, :lang(zh) h2, :lang(zh) h3 { word-break: keep-all; }

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 76px; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }
body { margin: 0; background: var(--bg); color: var(--ink); font: 16px/1.65 Inter, system-ui, -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif; }
a { color: var(--accent); }
:focus-visible { outline: 2px solid var(--focus); outline-offset: 3px; }
img { display: block; max-width: 100%; height: auto; }

/* ---------- buttons ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px; min-height: 48px; padding: 0 22px; border-radius: 12px;
  border: 1px solid var(--amber); background: var(--amber); color: #0e1726; font: 700 16px/1 Inter, system-ui, sans-serif; text-decoration: none; cursor: pointer;
}
.btn:hover { filter: brightness(1.06); }
.btn.ghost { background: transparent; color: var(--board-ink); border-color: var(--board-line); }
.btn.ghost:hover { border-color: rgba(245, 181, 68, 0.7); }
.btn.small { min-height: 44px; padding: 0 16px; font-size: 14.5px; }
.icon-btn {
  display: inline-grid; place-items: center; width: 44px; height: 44px; flex: none; border-radius: 12px; cursor: pointer;
  color: var(--board-ink); background: rgba(var(--glass), 0.05); border: 1px solid var(--board-line);
}
.theme-btn .theme-sun { display: none; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .theme-btn .theme-sun { display: block; }
  :root:not([data-theme="light"]) .theme-btn .theme-moon { display: none; }
}
:root[data-theme="dark"] .theme-btn .theme-sun { display: block; }
:root[data-theme="dark"] .theme-btn .theme-moon { display: none; }

/* ---------- the bar ---------- */
.top { position: sticky; top: 0; z-index: 10; background: var(--board); color: var(--board-ink); border-bottom: 1px solid var(--board-line); }
.top-inner { max-width: 1200px; margin: 0 auto; padding: 8px 24px; min-height: 60px; display: flex; align-items: center; gap: 12px; }
.brand { display: inline-flex; align-items: center; gap: 10px; min-height: 44px; color: var(--board-ink); text-decoration: none; font: 700 21px/1 var(--display); }
.logo { display: inline-grid; place-items: center; width: 32px; height: 32px; border-radius: 9px; background: var(--amber); color: #0e1726; font-weight: 800; font-size: 18px; }
.sections { display: flex; gap: 4px; margin-left: 18px; }
.sections a { display: inline-flex; align-items: center; min-height: 44px; padding: 0 10px; border-radius: 10px; color: var(--board-muted); text-decoration: none; font-size: 14.5px; font-weight: 600; }
.sections a:hover { color: var(--board-ink); background: rgba(var(--glass), 0.06); }
.lang { display: flex; align-items: center; gap: 4px; margin-left: auto; font-size: 13px; color: var(--board-muted); }
.lang button { min-width: 44px; min-height: 44px; padding: 0 6px; border: 1px solid transparent; border-radius: 8px; background: transparent; color: inherit; font: inherit; cursor: pointer; }
.lang button[aria-pressed="true"] { color: var(--board-ink); border-color: var(--board-line); font-weight: 700; }

/* ---------- the top of the page ---------- */
.hero { background: radial-gradient(1200px 500px at 85% -10%, var(--board-2), transparent 60%), var(--board); color: var(--board-ink); overflow: hidden; }
.hero { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.15fr); gap: 48px; align-items: center; padding: 64px max(24px, calc((100vw - 1200px) / 2)) 72px; }
.kicker { margin: 0 0 14px; color: var(--board-accent); font: 700 13px/1.4 var(--display); letter-spacing: 0.08em; text-transform: uppercase; }
.hero h1 { margin: 0; font: 700 clamp(32px, 4.2vw, 52px)/1.12 var(--display); letter-spacing: -0.01em; }
.lead { margin: 20px 0 0; color: var(--board-muted); font-size: 18px; max-width: 34em; }
.cta { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 28px; }
.fine { margin: 18px 0 0; color: var(--board-muted); font-size: 13.5px; max-width: 36em; }
.shot { margin: 0; border-radius: 14px; overflow: hidden; border: 1px solid var(--line); background: var(--surface); box-shadow: var(--shadow); }
.hero-shot { border-color: var(--board-line); box-shadow: var(--hero-shadow); }

/* ---------- numbers ---------- */
.numbers { max-width: 1200px; margin: -36px auto 0; padding: 0 24px; display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); gap: 12px; position: relative; }
.numbers div { background: var(--surface); border: 1px solid var(--line); border-radius: 14px; padding: 18px 16px; box-shadow: var(--shadow); }
.numbers b { display: block; font: 700 30px/1.1 var(--display); color: var(--ink); }
.numbers span { display: block; margin-top: 6px; color: var(--muted); font-size: 14px; line-height: 1.4; }

/* ---------- sections ---------- */
main > section { max-width: 1200px; margin: 0 auto; padding: 72px 24px 0; }
h2 { margin: 0 0 28px; font: 700 clamp(26px, 3vw, 36px)/1.2 var(--display); }
h3 { margin: 0 0 10px; font: 700 21px/1.3 var(--display); }
.feature { display: grid; grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.15fr); gap: 40px; align-items: center; padding: 28px 0; }
.feature.flip .text { order: 2; }
.feature p, .minis p, .how li, .install p, .install li, .faq p { color: var(--muted); }
.feature p b { color: var(--ink); }
.minis { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 16px; margin-top: 24px; }
.minis article { background: var(--surface); border: 1px solid var(--line); border-radius: 14px; padding: 22px; }
.minis h3 { font-size: 18px; }
.minis p { margin: 0; }

.how ol { list-style: none; counter-reset: step; margin: 0 0 28px; padding: 0; display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 16px; }
.how li { counter-increment: step; background: var(--surface); border: 1px solid var(--line); border-radius: 14px; padding: 22px; }
.how li::before { content: counter(step); display: inline-grid; place-items: center; width: 36px; height: 36px; margin-bottom: 12px; border-radius: 10px; background: var(--board); color: var(--amber); font: 700 18px/1 var(--display); }
.how li b { display: block; color: var(--ink); margin-bottom: 4px; }

.install { }
.install > p:first-of-type { margin-top: -16px; }
.install ul { padding-left: 1.2em; }
.installed { font-weight: 650; color: var(--accent) !important; }

.faq details { border-bottom: 1px solid var(--line); }
.faq summary { display: flex; align-items: center; justify-content: space-between; gap: 12px; min-height: 56px; cursor: pointer; font-weight: 650; font-size: 17px; list-style: none; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; flex: none; font: 400 26px/1 var(--display); color: var(--muted); }
.faq details[open] summary::after { content: "–"; }
.faq p { margin: 0 0 18px; max-width: 46em; }

.foot { max-width: 1200px; margin: 72px auto 0; padding: 24px 24px 28px; border-top: 1px solid var(--line); text-align: center; color: var(--muted); font-size: 13.5px; }
.foot p { margin: 0; }
.foot a { color: var(--muted); display: inline-flex; align-items: center; justify-content: center; min-height: 44px; min-width: 44px; padding: 0 4px; }
.foot .icp { font-size: 12px; }
.foot .icp a { text-decoration: none; }

/* ---------- narrower screens ---------- */
@media (max-width: 960px) {
  .sections { display: none; }
  .hero { grid-template-columns: 1fr; gap: 36px; padding-top: 44px; padding-bottom: 64px; }
  .numbers { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .numbers div:last-child { grid-column: 1 / -1; }
  .feature { grid-template-columns: 1fr; gap: 18px; }
  .feature.flip .text { order: 0; }
  .minis, .how ol { grid-template-columns: 1fr; }
}
@media (max-width: 640px) {
  .top-inner { padding: 6px 12px; gap: 6px; }
  .brand { font-size: 19px; }
  .top .btn.small { display: none; } /* the page's own big button opens the app */
  .hero { padding-left: 16px; padding-right: 16px; }
  .lead { font-size: 16.5px; }
  .cta .btn { flex: 1 1 100%; }
  .numbers { padding: 0 16px; }
  .numbers b { font-size: 26px; }
  main > section { padding: 56px 16px 0; }
  .foot { padding-left: 16px; padding-right: 16px; }
}