:root {
  --bg: #f6f7f9;
  --surface: #ffffff;
  --text: #16181d;
  --muted: #5a6170;
  --border: #e2e5ea;
  --accent: #1f6fd1;
  --accent-text: #ffffff;
  --hero-from: #2e4296;
  --hero-to: #1a92be;
  --code-bg: #eef1f5;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #111317;
    --surface: #1a1d23;
    --text: #eceef2;
    --muted: #a2a9b6;
    --border: #2c3039;
    --accent: #6aa8ff;
    --accent-text: #0d1420;
    --code-bg: #232731;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #111317; --surface: #1a1d23; --text: #eceef2; --muted: #a2a9b6;
  --border: #2c3039; --accent: #6aa8ff; --accent-text: #0d1420; --code-bg: #232731;
  color-scheme: dark;
}

* { 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", "Helvetica Neue", Arial, sans-serif;
}
a { color: var(--accent); }
a:hover { text-decoration-thickness: 2px; }
img { max-width: 100%; height: auto; display: block; }

.wrap { max-width: 860px; margin: 0 auto; padding: 0 16px; }

/* top bar */
.bar { background: var(--surface); border-bottom: 1px solid var(--border); }
.bar .wrap { display: flex; align-items: center; justify-content: space-between; gap: 16px; min-height: 60px; flex-wrap: wrap; }
.brand { display: flex; align-items: center; gap: 10px; color: var(--text); text-decoration: none; font-weight: 700; font-size: 19px; }
.brand img { width: 32px; height: 32px; }
.bar nav { display: flex; gap: 20px; font-size: 15px; }
.bar nav a { color: var(--muted); text-decoration: none; }
.bar nav a:hover, .bar nav a[aria-current="page"] { color: var(--text); }

/* home hero */
.hero { background: linear-gradient(180deg, var(--hero-from), var(--hero-to)); color: #fff; text-align: center; padding: 56px 0 0; overflow: hidden; }
.hero .icon { width: 112px; height: 112px; margin: 0 auto 18px; }
.hero h1 { font-size: clamp(34px, 6vw, 52px); line-height: 1.1; margin: 0 0 12px; letter-spacing: -0.02em; }
.hero p { font-size: clamp(17px, 2.6vw, 21px); margin: 0 auto 26px; max-width: 34em; opacity: 0.92; }
.badge { display: inline-block; background: #fff; color: #16181d; border-radius: 999px; padding: 10px 22px; font-weight: 600; font-size: 15px; text-decoration: none; }
.hero .shot { max-width: 1000px; margin: 40px auto 0; padding: 0 16px; }
.hero .shot img { border-radius: 12px 12px 0 0; box-shadow: 0 -4px 40px rgba(0, 0, 0, 0.25); }

.features { display: grid; grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); gap: 16px; margin: 40px 0; }
.card { background: var(--surface); border: 1px solid var(--border); border-radius: 12px; padding: 18px 20px; }
.card h3 { margin: 0 0 6px; font-size: 17px; }
.card p { margin: 0; color: var(--muted); font-size: 15px; }

/* article pages */
main.page { padding: 40px 0 56px; }
.page h1 { font-size: clamp(30px, 5vw, 40px); line-height: 1.15; margin: 0 0 8px; letter-spacing: -0.015em; }
.page .lead { color: var(--muted); font-size: 19px; margin: 0 0 28px; }
.page h2 { font-size: 23px; margin: 40px 0 10px; padding-top: 8px; }
.page h3 { font-size: 18px; margin: 24px 0 6px; }
.page p, .page li { max-width: 42em; }
.page ul, .page ol { padding-left: 1.3em; }
.page li { margin: 4px 0; }
.meta { color: var(--muted); font-size: 15px; }
.contact { background: var(--surface); border: 1px solid var(--border); border-radius: 12px; padding: 18px 20px; margin: 20px 0 8px; }
.contact p { margin: 4px 0; }
.toc { background: var(--surface); border: 1px solid var(--border); border-radius: 12px; padding: 14px 20px; margin: 0 0 8px; }
.toc ul { margin: 6px 0; padding-left: 1.1em; columns: 2 220px; }
code, pre { font: 14px/1.5 ui-monospace, "SF Mono", Menlo, monospace; background: var(--code-bg); border-radius: 6px; }
code { padding: 1px 5px; }
pre { padding: 12px 14px; overflow-x: auto; }
kbd { font: 13px ui-monospace, "SF Mono", Menlo, monospace; border: 1px solid var(--border); border-bottom-width: 2px; border-radius: 5px; padding: 0 5px; background: var(--surface); }

footer { border-top: 1px solid var(--border); color: var(--muted); font-size: 14px; padding: 22px 0 40px; }
footer .wrap { display: flex; justify-content: space-between; gap: 12px; flex-wrap: wrap; }
footer a { color: var(--muted); }