:root {
  color-scheme: light;
  --bg: #f6f7f9;
  --surface: #ffffff;
  --text: #17202a;
  --muted: #5b6673;
  --border: #d9dee5;
  --accent: #175cd3;
  --accent-strong: #0f4db7;
  --notice: #f7f8fa;
  --max: 880px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.62;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--surface);
  color: var(--accent);
  padding: .75rem 1rem;
  z-index: 10;
}

.skip-link:focus { left: 1rem; top: 1rem; }

header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
}

.header-inner,
main,
footer .footer-inner {
  width: min(var(--max), calc(100% - 2rem));
  margin: 0 auto;
}

.header-inner { padding: 1.3rem 0 1rem; }

.brand {
  margin: 0;
  font-size: 1.35rem;
  letter-spacing: .01em;
}

.brand small {
  display: block;
  margin-top: .15rem;
  color: var(--muted);
  font-size: .82rem;
  font-weight: 400;
}

nav {
  display: flex;
  flex-wrap: wrap;
  gap: .85rem 1.1rem;
  margin-top: .85rem;
}

nav a, a { color: var(--accent); }
nav a:hover, a:hover { color: var(--accent-strong); }
nav a { font-weight: 600; text-decoration-thickness: .08em; text-underline-offset: .15em; }

main { padding: 2.2rem 0 3rem; }

.hero,
.card,
.notice {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
}

.hero { padding: 1.6rem; margin-bottom: 1.2rem; }
.hero h1 { margin-top: 0; line-height: 1.2; }
.hero p:last-child { margin-bottom: 0; }

.card { padding: 1.35rem; margin: 1rem 0; }
.card h2, .card h3 { margin-top: 0; }

.notice {
  padding: 1rem 1.1rem;
  margin: 1rem 0;
  background: var(--notice);
}

.meta {
  color: var(--muted);
  font-size: .95rem;
}

h1, h2, h3 { line-height: 1.28; }
h2 { margin-top: 2rem; }
code {
  background: #eef1f4;
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: .08rem .28rem;
  font-size: .92em;
}

ul, ol { padding-left: 1.35rem; }
li + li { margin-top: .35rem; }

.lang-jump {
  display: flex;
  gap: .75rem;
  flex-wrap: wrap;
  margin: .8rem 0 0;
}

.lang-jump a {
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: .35rem .7rem;
  text-decoration: none;
  background: var(--surface);
}

footer {
  border-top: 1px solid var(--border);
  background: var(--surface);
}

.footer-inner {
  padding: 1.4rem 0 2rem;
  color: var(--muted);
  font-size: .9rem;
}

address { font-style: normal; }

@media (max-width: 600px) {
  main { padding-top: 1.35rem; }
  .hero, .card { padding: 1rem; }
  nav { gap: .55rem .8rem; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}