:root {
  --navy: #101a2e;
  --paper: #ffffff;
  --text: #252a33;
  --muted: #677181;
  --line: #d8dfe7;
  --link: #38598b;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--text);
  background: var(--navy);
  font-family:
    -apple-system,
    BlinkMacSystemFont,
    "Hiragino Sans",
    "Yu Gothic",
    sans-serif;
  line-height: 1.8;
}

main {
  width: min(680px, calc(100% - 32px));
  margin: 48px auto;
  padding: 40px;
  background: var(--paper);
  border-radius: 16px;
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.3);
}

.brand {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  margin-bottom: 18px;
}

.brand-mark {
  display: none;
}

.brand-name {
  color: var(--muted);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.14em;
}

.language-link {
  color: var(--navy);
  font-size: 13px;
  font-weight: 600;
  text-decoration: none;
}

.language-link:hover {
  text-decoration: underline;
}

h1 {
  margin: 0;
  padding-bottom: 12px;
  color: var(--navy);
  border-bottom: 2px solid var(--navy);
  font-size: clamp(1.8rem, 5vw, 2.2rem);
  line-height: 1.4;
}

h2 {
  margin: 32px 0 10px;
  color: var(--navy);
  font-size: 1.25rem;
}

p {
  margin: 1em 0;
}

.lead {
  margin: 24px 0 32px;
}

.updated {
  color: var(--muted);
  font-size: 14px;
}

ol,
ul {
  padding-left: 1.5em;
}

li + li {
  margin-top: 0.5em;
}

a {
  color: var(--link);
  text-underline-offset: 3px;
  overflow-wrap: anywhere;
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 24px;
  font-size: 14px;
  text-decoration: none;
}

.back-link:hover {
  text-decoration: underline;
}

.panel {
  margin-top: 32px;
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: #f7f8fa;
}

.panel h2 {
  margin-top: 0;
}

.links {
  display: grid;
  gap: 10px;
  margin-top: 32px;
}

.links a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 50px;
  padding: 11px 16px;
  color: var(--navy);
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #f7f8fa;
  font-weight: 600;
  text-decoration: none;
}

.links a::after {
  content: "→";
  color: var(--muted);
}

.links a:hover {
  border-color: var(--navy);
}

footer {
  margin-top: 40px;
  color: var(--muted);
  font-size: 14px;
}

footer p {
  margin: 0;
}

@media (max-width: 600px) {
  main {
    margin: 20px auto;
    padding: 24px;
  }
}

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