/* BySwap public site (byswap.io): static pages, no script, nothing loaded from elsewhere. Light and dark follow the
   system setting. Colours are BySwap's own: the mark's violet-to-blue gradient (#8b5cff, #5b6cff, #2f8dff). */
:root {
  --bg: #ffffff;
  --fg: #14161c;
  --muted: #545b6b;
  --line: #e1e4ec;
  --panel: #f6f7fb;
  --accent: #4b5cf0;
  --accent-strong: #3445d6;
  --focus: #2f8dff;
  --warn-bg: #fff4d6;
  --warn-fg: #5c4400;
  --hero: linear-gradient(135deg, rgba(139, 92, 255, 0.14), rgba(91, 108, 255, 0.1) 55%, rgba(47, 141, 255, 0.12));
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0c0e13;
    --fg: #e9ebf2;
    --muted: #a3a9b8;
    --line: #262a36;
    --panel: #141721;
    --accent: #9aa6ff;
    --accent-strong: #b8c0ff;
    --focus: #6fb0ff;
    --warn-bg: #3a2f0b;
    --warn-fg: #ffe7a3;
    --hero: linear-gradient(135deg, rgba(139, 92, 255, 0.22), rgba(91, 108, 255, 0.14) 55%, rgba(47, 141, 255, 0.18));
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-padding-top: 16px; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font: 16px/1.65 system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  overflow-wrap: break-word;
}
a { color: var(--accent); text-underline-offset: 2px; }
a:hover { color: var(--accent-strong); }
a:focus-visible, main:focus-visible { outline: 3px solid var(--focus); outline-offset: 2px; border-radius: 4px; }
main:focus { outline: none; }
img { max-width: 100%; height: auto; }
.wrap { max-width: 880px; margin: 0 auto; padding: 0 16px; }
.skip { position: absolute; left: 8px; top: -48px; background: var(--fg); color: var(--bg); padding: 8px 12px; border-radius: 6px; z-index: 10; }
.skip:focus { top: 8px; }
.draft { background: var(--warn-bg); color: var(--warn-fg); padding: 10px 16px; font-weight: 600; text-align: center; }
mark.missing { background: var(--warn-bg); color: var(--warn-fg); padding: 0 4px; border-radius: 4px; }
.review { display: inline-block; vertical-align: middle; margin-left: 8px; font-size: 0.75rem; font-weight: 600; line-height: 1.4; background: var(--warn-bg); color: var(--warn-fg); padding: 2px 8px; border-radius: 999px; }

.top { border-bottom: 1px solid var(--line); }
.top .wrap { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 8px 16px; padding-top: 16px; padding-bottom: 16px; }
.brand { display: inline-flex; align-items: center; gap: 10px; color: var(--fg); text-decoration: none; font-weight: 700; font-size: 1.25rem; letter-spacing: -0.01em; }
.brand img { border-radius: 8px; }
nav a { display: inline-block; padding: 6px 2px; margin-right: 16px; text-decoration: none; }
nav a:last-child { margin-right: 0; }
nav a[aria-current="page"] { color: var(--fg); font-weight: 600; text-decoration: underline; text-decoration-thickness: 2px; text-underline-offset: 6px; }

main { display: block; padding-bottom: 48px; }
h1 { font-size: clamp(1.9rem, 5vw, 2.6rem); line-height: 1.15; margin: 0 0 12px; letter-spacing: -0.02em; }
h2 { font-size: 1.3rem; line-height: 1.3; margin: 40px 0 10px; }
h3 { font-size: 1.05rem; margin: 0 0 4px; }
.lead { font-size: 1.15rem; color: var(--muted); margin-top: 0; }

.hero { background: var(--hero); border-bottom: 1px solid var(--line); padding: 48px 0 40px; margin-bottom: 8px; }
.hero-mark { display: block; border-radius: 18px; margin-bottom: 16px; }
.status { display: inline-block; margin: 8px 0 0; background: var(--bg); border: 1px solid var(--line); border-radius: 999px; padding: 6px 14px; font-weight: 600; }

.features { list-style: none; padding: 0; display: grid; gap: 12px; grid-template-columns: repeat(auto-fit, minmax(min(100%, 300px), 1fr)); }
.features li { background: var(--panel); border: 1px solid var(--line); border-radius: 12px; padding: 16px; }
.features p { margin: 0; color: var(--muted); }
.checks { padding-left: 20px; }
.checks li { margin: 6px 0; }

.doc { padding-top: 32px; }
.doc section { scroll-margin-top: 16px; }
.doc li { margin: 6px 0; }
.toc { background: var(--panel); border: 1px solid var(--line); border-radius: 12px; padding: 4px 20px 8px; margin: 24px 0 8px; }
.toc h2 { font-size: 1rem; margin: 12px 0 4px; }
.toc ol { margin: 4px 0; padding-left: 20px; }
@media (min-width: 640px) { .toc ol { columns: 2; column-gap: 32px; } }
.toc li { margin: 4px 0; }
.toc a { display: inline; padding: 0; margin: 0; }

.foot { border-top: 1px solid var(--line); color: var(--muted); font-size: 0.9rem; }
.foot .wrap { padding-top: 20px; padding-bottom: 32px; }
.foot p { margin: 8px 0 0; }

@media (max-width: 520px) {
  .hero { padding: 32px 0 28px; }
  .hero-mark { width: 56px; height: 56px; }
  nav a { margin-right: 12px; }
}
@media (prefers-reduced-motion: reduce) { * { scroll-behavior: auto !important; } }
@media print { .skip, .top nav, .draft { display: none; } a { color: inherit; } }