:root {
  color-scheme: light dark;
  /* Surfaces follow the app window: white content, cool blue-grey sidebar. */
  --bg: #ffffff;
  --bg-alt: #f3f5f9;
  --text: #1d1d1f;
  --muted: #5f6672;
  --line: #e1e5ec;
  --card: #ffffff;
  /* Accent is the app's own blue (Start Scan, selection), slightly deepened for text contrast. */
  --accent: #2f6fe4;
  --accent-strong: #1f58c4;
  --on-accent: #ffffff;
  /* The logo's two cards; decorative only. */
  --teal: #6fd7e1;
  --coral: #fbaf90;
  --radius: 14px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #1c1c1e;
    --bg-alt: #252528;
    --text: #f5f5f7;
    --muted: #a3a8b3;
    --line: #38383d;
    --card: #2c2c2e;
    --accent: #6ea4ff;
    --accent-strong: #93bbff;
    --on-accent: #07142e;
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: 76px; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.7 -apple-system, BlinkMacSystemFont, "SF Pro Text", "Helvetica Neue",
    "PingFang SC", "PingFang TC", "Hiragino Sans", "Apple SD Gothic Neo", "Segoe UI", sans-serif;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img { max-width: 100%; height: auto; }

a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 3px; }
a:hover { color: var(--accent-strong); }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 4px; }

h1, h2, h3 { margin: 0; font-weight: 700; letter-spacing: -0.025em; line-height: 1.12; }

.wrap { width: min(1080px, 100% - 48px); margin-inline: auto; }
/* Narrow sections keep the same left edge as the rest; only the text measure is limited. */
.narrow > * { max-width: 760px; }

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: var(--bg);
  border-bottom: 1px solid var(--line);
}

.bar { display: flex; align-items: center; gap: 20px; min-height: 64px; }

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  font-weight: 700;
  font-size: 20px;
  letter-spacing: -0.02em;
  text-decoration: none;
}
.brand img { border-radius: 8px; }

.nav { display: flex; gap: 2px; margin-left: 12px; flex: 1; }
.nav a {
  color: var(--muted);
  text-decoration: none;
  padding: 6px 12px;
  border-radius: 8px;
  font-size: 15px;
  white-space: nowrap;
}
.nav a:hover, .nav a[aria-current] { color: var(--text); }
.nav a[aria-current] { text-decoration: underline; text-underline-offset: 8px; text-decoration-color: var(--coral); text-decoration-thickness: 2px; }

.bar-end { display: flex; align-items: center; gap: 8px; }
.gh { color: var(--muted); text-decoration: none; font-size: 15px; padding: 6px 10px; }
.gh:hover { color: var(--text); }

.lang { position: relative; }
.lang summary {
  list-style: none;
  cursor: pointer;
  font-size: 15px;
  padding: 6px 12px;
  border: 1px solid var(--line);
  border-radius: 999px;
  white-space: nowrap;
  color: var(--text);
}
.lang summary:hover { border-color: var(--muted); }
.lang summary::-webkit-details-marker { display: none; }
.lang ul {
  position: absolute;
  right: 0;
  top: calc(100% + 8px);
  margin: 0;
  padding: 6px;
  list-style: none;
  min-width: 160px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 12px;
}
.lang li a { display: block; padding: 7px 10px; border-radius: 8px; color: var(--text); text-decoration: none; font-size: 15px; }
.lang li a:hover { background: var(--bg-alt); }
.lang li a[aria-current] { color: var(--accent); font-weight: 600; }

/* Hero */
.hero { padding: 88px 0 72px; }
.hero-icon { border-radius: 18px; display: block; border: 1px solid var(--line); }
.hero h1 {
  font-size: clamp(36px, 6vw, 64px);
  letter-spacing: -0.04em;
  margin: 28px 0 0;
  max-width: 14em;
  text-wrap: balance;
}
.lead { color: var(--muted); font-size: 20px; max-width: 36em; margin: 22px 0 0; text-wrap: pretty; }
.cta { display: flex; flex-wrap: wrap; gap: 12px; margin: 36px 0 0; }

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 24px;
  border-radius: 10px;
  border: 1px solid var(--line);
  background: transparent;
  color: var(--text);
  font-weight: 600;
  text-decoration: none;
  transition: background-color 0.15s ease, border-color 0.15s ease;
}
.btn:hover { border-color: var(--muted); color: var(--text); }
.btn.primary { background: var(--accent); border-color: var(--accent); color: var(--on-accent); }
.btn.primary:hover { background: var(--accent-strong); border-color: var(--accent-strong); color: var(--on-accent); }
.btn .ver { font-weight: 500; opacity: 0.8; font-size: 0.9em; }

.req { color: var(--muted); font-size: 15px; margin: 22px 0 0; }
.latest { color: var(--muted); font-size: 14px; margin: 2px 0 0; }

.hero-shot {
  display: block;
  margin-top: 56px;
  border-radius: 16px;
  border: 1px solid var(--line);
  width: 100%;
}

/* Sections */
.section { padding: 88px 0; }
.section.alt { background: var(--bg-alt); }
.section h2 { font-size: clamp(30px, 3.6vw, 42px); margin-bottom: 44px; }
.section h1 { font-size: clamp(34px, 4.4vw, 52px); }

.grid {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 40px 48px;
  counter-reset: feature;
}
.card { counter-increment: feature; border-top: 3px solid var(--teal); padding-top: 18px; }
.card:nth-child(even) { border-top-color: var(--coral); }
.card::before {
  content: counter(feature, decimal-leading-zero);
  display: block;
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--muted);
  margin-bottom: 10px;
}
.card h3 { font-size: 22px; margin-bottom: 10px; }
.card p { margin: 0; color: var(--muted); font-size: 16px; }

.shots { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 460px), 1fr)); gap: 40px 32px; }
.shots figure { margin: 0; }
.shots img { width: 100%; border-radius: 14px; border: 1px solid var(--line); background: var(--card); }
.shots figcaption { color: var(--muted); font-size: 15px; margin-top: 14px; }

.steps { list-style: none; margin: 0; padding: 0; counter-reset: step; }
.steps li {
  counter-increment: step;
  display: grid;
  grid-template-columns: 44px 1fr;
  padding: 20px 0;
  border-top: 1px solid var(--line);
}
.steps li:last-child { border-bottom: 1px solid var(--line); }
.steps li::before { content: counter(step); font-size: 22px; font-weight: 700; line-height: 1.3; color: var(--accent); }

.faq details { border-top: 1px solid var(--line); }
.faq details:last-child { border-bottom: 1px solid var(--line); }
.faq summary {
  cursor: pointer;
  font-weight: 600;
  padding: 18px 36px 18px 0;
  position: relative;
  list-style: none;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; position: absolute; right: 4px; top: 12px; font-size: 24px; font-weight: 400; color: var(--accent); }
.faq details[open] summary::after { content: "–"; }
.faq details p { margin: 0 0 20px; color: var(--muted); max-width: 40em; }

/* Changelog */
.crumbs { color: var(--muted); font-size: 15px; margin-bottom: 18px; }
.crumbs a { color: var(--muted); }
.section h1 + .lead { margin-top: 12px; }
.release { border-top: 1px solid var(--line); padding: 32px 0; margin-top: 8px; }
.release h2 { font-size: 28px; margin-bottom: 6px; }
.release .meta { color: var(--muted); font-size: 15px; margin: 0 0 16px; }
.release ul { padding-left: 1.3em; }
.release li { margin: 8px 0; }
.release code, .faq code { background: var(--bg-alt); border-radius: 6px; padding: 1px 6px; font-size: 0.9em; }

.notfound { text-align: center; padding: 80px 0; }
.notfound img { border-radius: 16px; margin-bottom: 16px; }

/* Footer */
.site-footer { border-top: 1px solid var(--line); padding: 36px 0 56px; color: var(--muted); font-size: 15px; }
.site-footer p { margin: 4px 0; }
.site-footer a { color: var(--muted); }
.site-footer a:hover { color: var(--text); }

@media (max-width: 720px) {
  body { font-size: 16px; }
  .bar { flex-wrap: wrap; row-gap: 0; padding-top: 8px; }
  .bar-end { margin-left: auto; }
  .nav { order: 3; flex-basis: 100%; flex-wrap: wrap; margin: 0 -12px; padding-bottom: 6px; }
  .gh { display: none; }
  .hero { padding: 48px 0 48px; }
  .hero-shot { margin-top: 40px; }
  .section { padding: 60px 0; }
  .lead { font-size: 18px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .btn { transition: none; }
}