/* QiuDisplay — product site. System fonts, no external dependencies, light / dark follows the system. */
:root {
  --bg: #ffffff;
  --bg-soft: #f5f6f8;
  --text: #16181d;
  --muted: #5d6470;
  --line: #e3e6eb;
  --accent: #1f6fff;
  --accent-text: #ffffff;
  --card: #ffffff;
  --radius: 16px;
  --max: 1080px;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0e1013;
    --bg-soft: #16191e;
    --text: #eef0f3;
    --muted: #a0a7b2;
    --line: #262a31;
    --accent: #4c8dff;
    --card: #15181d;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.6 -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", "PingFang SC", "Hiragino Sans GB",
        "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
img { max-width: 100%; display: block; }
.wrap { max-width: var(--max); margin: 0 auto; padding: 0 24px; }

/* Header */
.top { border-bottom: 1px solid var(--line); position: sticky; top: 0; background: color-mix(in srgb, var(--bg) 88%, transparent);
       backdrop-filter: saturate(180%) blur(16px); -webkit-backdrop-filter: saturate(180%) blur(16px); z-index: 10; }
.top .wrap { display: flex; align-items: center; justify-content: space-between; height: 60px; gap: 16px; }
.brand { display: flex; align-items: center; gap: 10px; color: var(--text); font-weight: 650; font-size: 18px; }
.brand:hover { text-decoration: none; }
.brand img { width: 30px; height: 30px; border-radius: 7px; }
.nav { display: flex; align-items: center; gap: 22px; font-size: 15px; }
.nav a { color: var(--muted); }
.nav a:hover, .nav a[aria-current="page"] { color: var(--text); text-decoration: none; }
.lang { border: 1px solid var(--line); border-radius: 999px; padding: 3px 11px; }
@media (max-width: 820px) { .nav .hide-s { display: none; } .nav { gap: 16px; } }
@media (max-width: 480px) { .nav .hide-m { display: none; } .nav { gap: 14px; } }

/* Buttons */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; min-height: 48px; padding: 0 22px;
       border-radius: 12px; font-weight: 600; font-size: 16px; border: 1px solid transparent; }
.btn:hover { text-decoration: none; }
.btn-primary { background: var(--accent); color: var(--accent-text); }
.btn-primary:hover { filter: brightness(1.08); }
.btn-secondary { border-color: var(--line); color: var(--text); background: var(--card); }
.btn[aria-disabled="true"] { color: var(--muted); cursor: default; }
.ctas { display: flex; flex-wrap: wrap; gap: 12px; }
.fine { color: var(--muted); font-size: 14px; margin-top: 14px; }

/* Hero */
.hero { padding: 72px 0 48px; text-align: center; }
.hero h1 { font-size: clamp(36px, 6vw, 60px); line-height: 1.08; letter-spacing: -0.02em; margin: 0 auto 18px; max-width: 14em; }
.hero .lead { font-size: clamp(18px, 2.2vw, 21px); color: var(--muted); max-width: 40em; margin: 0 auto 30px; }
.hero .ctas { justify-content: center; }
.eyebrow { font-weight: 600; color: var(--accent); letter-spacing: .02em; margin-bottom: 10px; }

/* Illustration: drawn with CSS, not an app screenshot */
.stage { margin: 56px auto 0; max-width: 760px; display: flex; align-items: flex-end; justify-content: center; gap: 22px; }
.mac { flex: 0 1 470px; }
.mac .screen, .pad .screen { position: relative; border-radius: 12px; border: 10px solid #1b1d22; aspect-ratio: 16 / 10;
  background: linear-gradient(135deg, #2f80ff 0%, #6a5cff 45%, #ff8a4c 100%); overflow: hidden; }
.mac .stand { width: 22%; height: 34px; margin: 0 auto; background: linear-gradient(#c9ccd2, #a9adb5); clip-path: polygon(12% 0, 88% 0, 100% 100%, 0 100%); }
.mac .foot { width: 34%; height: 6px; margin: 0 auto; border-radius: 3px; background: #b5b9c0; }
.pad { flex: 0 1 230px; margin-bottom: 40px; }
.pad .screen { border-width: 9px; border-radius: 16px; aspect-ratio: 4 / 3; background: linear-gradient(135deg, #6a5cff 0%, #ff8a4c 100%); }
.win { position: absolute; background: rgba(255,255,255,.88); border-radius: 6px; box-shadow: 0 6px 18px rgba(0,0,0,.18); }
.win::before { content: ""; position: absolute; top: 6px; left: 7px; width: 22px; height: 6px;
  background: radial-gradient(circle, #ff5f57 2.6px, transparent 3px) 0 0 / 8px 6px repeat-x; }
.mac .w1 { left: 8%; top: 14%; width: 52%; height: 58%; }
.mac .w2 { left: 64%; top: 30%; width: 30%; height: 46%; }
.pad .w3 { left: 10%; top: 16%; width: 62%; height: 64%; }
.menubar { position: absolute; left: 0; right: 0; top: 0; height: 5%; background: rgba(255,255,255,.35); }
@media (prefers-color-scheme: dark) { .mac .screen, .pad .screen { border-color: #2b2e35; } .win { background: rgba(30,32,38,.9); } }
@media (max-width: 560px) { .stage { gap: 12px; } .pad { margin-bottom: 26px; } .mac .stand { height: 22px; } }

/* Sections */
section { padding: 72px 0; }
section.soft { background: var(--bg-soft); }
h1, h2, h3, .lead, .sub { text-wrap: balance; }
h2 { font-size: clamp(28px, 4vw, 40px); line-height: 1.15; letter-spacing: -0.015em; margin: 0 0 14px; }
.sub { color: var(--muted); font-size: 19px; max-width: 42em; margin: 0 0 40px; }
.grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 28px 36px; }
.feature h3 { font-size: 19px; margin: 0 0 6px; }
.feature p { margin: 0; color: var(--muted); }

.settings { display: grid; grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); gap: 18px; }
@media (max-width: 1000px) { .settings { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 560px) { .settings { grid-template-columns: 1fr; } }
.setting { border: 1px solid var(--line); border-radius: var(--radius); padding: 20px 22px; background: var(--card); }
.setting h3 { margin: 0 0 4px; font-size: 18px; }
.setting p { margin: 0 0 14px; color: var(--muted); font-size: 15px; }
.chips { display: flex; flex-wrap: wrap; gap: 6px; padding: 0; margin: 0; list-style: none; }
.chips li { font-size: 14px; border: 1px solid var(--line); border-radius: 999px; padding: 3px 11px; }

.steps { counter-reset: s; list-style: none; padding: 0; margin: 0 0 32px; display: grid; gap: 14px;
  grid-template-columns: repeat(auto-fit, minmax(128px, 1fr)); }
.steps li { counter-increment: s; border-top: 2px solid var(--accent); padding-top: 12px; }
.steps li::before { content: counter(s); display: block; font-weight: 700; color: var(--accent); font-size: 15px; margin-bottom: 2px; }
.reqs { display: flex; flex-wrap: wrap; gap: 10px 28px; color: var(--muted); padding: 0; list-style: none; margin: 0; }
.reqs strong { color: var(--text); }

.privacy-hero { text-align: center; }
.privacy-hero h2 { margin-bottom: 10px; }
.privacy-hero .sub { margin: 0 auto 8px; }

.download { text-align: center; }
.download .sub { margin: 0 auto 28px; }
.download .ctas { justify-content: center; }
.hash { font: 12px/1.5 ui-monospace, SFMono-Regular, Menlo, monospace; color: var(--muted); word-break: break-all; margin-top: 18px; }

/* Documents (privacy / support) */
.doc { max-width: 760px; padding: 56px 24px 80px; }
.doc h1 { font-size: clamp(32px, 5vw, 44px); line-height: 1.1; letter-spacing: -0.02em; margin: 0 0 8px; }
.doc .meta { color: var(--muted); margin: 0 0 36px; }
.doc h2 { font-size: 24px; margin: 44px 0 10px; }
.doc h3 { font-size: 18px; margin: 26px 0 6px; }
.doc ul, .doc ol { padding-left: 1.3em; }
.doc li { margin: 4px 0; }
.doc .callout { background: var(--bg-soft); border-radius: var(--radius); padding: 18px 22px; margin: 22px 0; }
.doc .callout ul { margin: 0; }
.toc { display: flex; flex-wrap: wrap; gap: 8px 18px; padding: 0; list-style: none; margin: 0 0 8px; font-size: 15px; }

/* Footer */
footer { border-top: 1px solid var(--line); padding: 28px 0 40px; color: var(--muted); font-size: 14px; }
footer .wrap { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 12px; }
footer nav { display: flex; flex-wrap: wrap; gap: 18px; }
footer a { color: var(--muted); }

.notfound { text-align: center; padding: 120px 24px; }

/* Download page */
.dl-card { border: 1px solid var(--line); border-radius: var(--radius); padding: 24px; background: var(--card); margin: 24px 0; }
.dl-card .ctas { margin: 8px 0 4px; }
.kv { display: grid; grid-template-columns: max-content 1fr; gap: 6px 18px; margin: 16px 0 0; font-size: 15px; }
.kv dt { color: var(--muted); }
.kv dd { margin: 0; overflow-wrap: anywhere; }
.kv dd code { word-break: break-all; }
code, pre { font: 14px/1.5 ui-monospace, SFMono-Regular, Menlo, monospace; }
pre { background: var(--bg-soft); border-radius: 10px; padding: 12px 14px; white-space: pre-wrap; word-break: break-all; }