:root {
  --bg: #151b33;
  --bg-elevated: #1c2444;
  --text: #eef1f8;
  --muted: #9aa3bd;
  --accent: #8b9cff;
  --line: #2a3358;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
}

body {
  font-family: "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Noto Sans JP",
    sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
}

html[lang="en"] body {
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
}

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

.wrap {
  max-width: 40rem;
  margin: 0 auto;
  padding: 2.5rem 1.25rem 4rem;
}

.top {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.lang-switch {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  margin: 0;
  padding: 0;
  border: 0;
  font-size: 0.8rem;
  color: var(--muted);
}

.lang-switch button {
  margin: 0;
  padding: 0;
  border: 0;
  background: none;
  color: var(--muted);
  font: inherit;
  cursor: pointer;
}

.lang-switch button:hover {
  color: var(--text);
}

html[lang="ja"] [data-set-lang="ja"],
html[lang="en"] [data-set-lang="en"] {
  color: var(--text);
  font-weight: 700;
}

.i18n {
  display: none;
}

html[lang="ja"] .i18n[lang="ja"],
html[lang="en"] .i18n[lang="en"] {
  display: block;
}

header {
  margin-bottom: 2rem;
}

.brand {
  font-weight: 700;
  letter-spacing: 0.04em;
  text-decoration: none;
  color: var(--text);
}

h1 {
  font-size: 1.75rem;
  line-height: 1.3;
  margin: 0.75rem 0 0.5rem;
}

h2 {
  font-size: 1.1rem;
  margin: 2rem 0 0.5rem;
}

p,
li {
  color: var(--muted);
}

.lead {
  color: var(--text);
}

nav {
  margin-top: 2.5rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--line);
  font-size: 0.9rem;
}

.updated {
  font-size: 0.85rem;
  color: var(--muted);
}