:root {
  --bg: #fdfdfc;
  --fg: #1c1c1a;
  --fg-muted: #5c5c56;
  --accent: #2563eb;
  --border: #e4e4de;
  --card: #f5f5f0;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #16161a;
    --fg: #e8e8e4;
    --fg-muted: #a0a09a;
    --accent: #7aa2f7;
    --border: #2e2e34;
    --card: #1f1f24;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0 auto;
  max-width: 44rem;
  padding: 2rem 1.25rem 4rem;
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Noto Sans JP", sans-serif;
  line-height: 1.8;
}

.hero {
  margin-top: 2rem;
  text-align: center;
}

.hero-emoji {
  margin: 0;
  font-size: 3rem;
  line-height: 1;
}

.hero h1 {
  margin: 0.5rem 0 0;
  font-size: 2rem;
  letter-spacing: 0.02em;
}

.tagline {
  color: var(--fg-muted);
  margin-top: 0.5rem;
}

.links {
  display: flex;
  gap: 1.5rem;
  flex-wrap: wrap;
  justify-content: center;
  margin-top: 1rem;
}

.section-note {
  color: var(--fg-muted);
  font-size: 0.9rem;
}

.tech {
  display: block;
  margin-top: 0.25rem;
  color: var(--fg-muted);
  font-size: 0.85rem;
}

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

.timeline li {
  margin: 0.75rem 0;
  padding-left: 0.25rem;
}

.timeline .year {
  display: inline-block;
  margin-right: 0.5rem;
  color: var(--fg-muted);
  font-variant-numeric: tabular-nums;
  font-size: 0.9rem;
}

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

h2 {
  margin-top: 3rem;
  padding-bottom: 0.4rem;
  border-bottom: 1px solid var(--border);
}

h3 {
  margin-top: 2.25rem;
}

article {
  margin: 1.25rem 0;
  padding: 1rem 1.25rem;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 8px;
}

article h4 {
  margin: 0 0 0.5rem;
}

article p,
article ul {
  margin: 0.5rem 0;
}

.unlock {
  margin: 1.5rem 0;
  padding: 1rem 1.25rem;
  border: 1px dashed var(--border);
  border-radius: 8px;
}

.unlock-note {
  margin: 0 0 0.75rem;
  color: var(--fg-muted);
  font-size: 0.9rem;
}

.unlock-row {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.unlock input {
  flex: 1 1 12rem;
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--bg);
  color: var(--fg);
  font-size: 1rem;
}

.unlock button {
  padding: 0.5rem 1.25rem;
  border: none;
  border-radius: 6px;
  background: var(--accent);
  color: #fff;
  font-size: 1rem;
  cursor: pointer;
}

.unlock button:disabled {
  opacity: 0.6;
  cursor: wait;
}

#unlock-status {
  margin: 0.5rem 0 0;
  font-size: 0.9rem;
  color: var(--fg-muted);
}

#unlock-status.error {
  color: #dc2626;
}

.masked-more {
  color: var(--fg-muted);
  font-size: 0.9rem;
}

footer {
  margin-top: 4rem;
  color: var(--fg-muted);
  font-size: 0.85rem;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}