:root {
  --bg: #121820;
  --fg: #e8eef5;
  --muted: #9aa8b8;
  --accent: #7dffa8;
  --line: #2a3544;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Segoe UI", "Hiragino Sans", "Noto Sans JP", sans-serif;
  background: var(--bg);
  color: var(--fg);
  line-height: 1.7;
}

.wrap {
  max-width: 42rem;
  margin: 0 auto;
  padding: 2.5rem 1.25rem 4rem;
}

.brand {
  margin: 0 0 0.35rem;
  font-size: 1.75rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--accent);
}

.lead {
  margin: 0 0 1.5rem;
  color: var(--muted);
}

.links {
  padding: 0;
  list-style: none;
}

.links li {
  margin: 0.4rem 0;
}

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

h1 {
  margin: 0 0 0.5rem;
  font-size: 1.5rem;
}

h2 {
  margin: 2rem 0 0.6rem;
  font-size: 1.05rem;
  border-top: 1px solid var(--line);
  padding-top: 1.25rem;
}

.meta {
  color: var(--muted);
  font-size: 0.9rem;
  margin: 0 0 1.5rem;
}

p,
li {
  font-size: 0.95rem;
}

ul {
  padding-left: 1.2rem;
}

.back {
  display: inline-block;
  margin-bottom: 1.5rem;
  color: var(--muted);
  text-decoration: none;
}

.back:hover {
  color: var(--accent);
}

.lang-switch {
  margin: 0 0 1.5rem;
  font-size: 0.9rem;
}

#en {
  scroll-margin-top: 1rem;
}