:root {
  --bg: #0f1114;
  --surface: #181b21;
  --text: #e8eaed;
  --muted: #9aa0a6;
  --accent: #7c9cff;
  --border: #2a2f38;
  --maxw: 42rem;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  font-size: 106%;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

a {
  color: var(--accent);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.2em;
}

a:hover {
  text-decoration: none;
}

header {
  padding: 1.75rem 1.25rem 1rem;
  border-bottom: 1px solid var(--border);
  background: var(--surface);
}

header h1 {
  margin: 0;
  font-size: 1.35rem;
  font-weight: 600;
  letter-spacing: -0.02em;
}

header p {
  margin: 0.35rem 0 0;
  color: var(--muted);
  font-size: 0.95rem;
}

main {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 2rem 1.25rem 3rem;
}

main h2 {
  margin: 2rem 0 0.75rem;
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text);
}

main h2:first-child {
  margin-top: 0;
}

main p,
main li {
  color: #c4c7ce;
  margin: 0.65rem 0;
}

main ul {
  padding-left: 1.25rem;
}

main .note {
  font-size: 0.9rem;
  color: var(--muted);
  border-left: 3px solid var(--border);
  padding-left: 1rem;
  margin: 1.5rem 0;
}

nav.lang {
  margin-top: 1rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.25rem;
  font-size: 0.9rem;
}

nav.lang a {
  color: var(--muted);
}

nav.lang a[aria-current="page"] {
  color: var(--accent);
  font-weight: 500;
}

footer {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 1.25rem 2.5rem;
  font-size: 0.85rem;
  color: var(--muted);
}

footer a {
  color: var(--muted);
}

footer a:hover {
  color: var(--accent);
}

.hub {
  text-align: center;
  padding: 3rem 1.25rem;
}

.hub h1 {
  font-size: 1.75rem;
  margin-bottom: 0.5rem;
}

.hub p {
  color: var(--muted);
  margin-bottom: 2rem;
}

.hub-bilingual {
  max-width: 26rem;
  margin-left: auto;
  margin-right: auto;
  line-height: 1.55;
}

.hub-sep {
  display: inline-block;
  margin: 0 0.35rem;
  opacity: 0.45;
}

.hub-hint {
  margin-top: 1.5rem;
  font-size: 0.92rem;
  color: var(--muted);
  max-width: 22rem;
  margin-left: auto;
  margin-right: auto;
}

.hub-hint a {
  font-weight: 500;
}

.hub .choices {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1rem;
}

.hub .choices a {
  display: inline-block;
  padding: 0.75rem 1.35rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  color: var(--text);
  text-decoration: none;
  font-weight: 500;
}

.hub .choices a:hover {
  border-color: var(--accent);
  color: var(--accent);
}