:root {
  --bg: #F7F5F0;
  --bg-elevated: #FFFFFF;
  --text: #0F1419;
  --text-secondary: #5A5F66;
  --text-tertiary: #9AA0A6;
  --accent: #5A8D7A;
  --accent-soft: #E8EFEB;
  --line: #E5E1D8;
  --max-width: 640px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #12120F;
    --bg-elevated: #1C1B17;
    --text: #EDE9DF;
    --text-secondary: #A8A59C;
    --text-tertiary: #6E6B62;
    --accent: #7AA898;
    --accent-soft: #1F2A26;
    --line: #2A2924;
  }
}

* {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  padding: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Hiragino Kaku Gothic ProN", "ヒラギノ角ゴ ProN W3", sans-serif;
  font-size: 17px;
  line-height: 1.75;
  color: var(--text);
  background: var(--bg);
  font-feature-settings: "palt";
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 48px 24px 80px;
}

.hero {
  text-align: center;
  padding: 48px 0 32px;
}

.hero h1 {
  font-size: 56px;
  font-weight: 700;
  letter-spacing: 0.04em;
  margin: 0 0 16px;
}

.hero .tagline {
  font-size: 20px;
  color: var(--accent);
  margin: 0 0 24px;
  font-weight: 500;
}

.hero .description {
  color: var(--text-secondary);
  font-size: 16px;
  line-height: 1.8;
  margin: 0;
}

.features {
  display: flex;
  flex-direction: column;
  gap: 24px;
  margin: 56px 0;
}

.feature {
  background: var(--bg-elevated);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 24px;
}

.feature h2 {
  font-size: 18px;
  margin: 0 0 8px;
  font-weight: 600;
}

.feature p {
  margin: 0;
  color: var(--text-secondary);
  font-size: 15px;
  line-height: 1.7;
}

.article h1 {
  font-size: 32px;
  font-weight: 700;
  letter-spacing: 0.02em;
  margin: 0 0 8px;
}

.article h2 {
  font-size: 22px;
  font-weight: 600;
  margin: 48px 0 16px;
  letter-spacing: 0.02em;
}

.article h3 {
  font-size: 17px;
  font-weight: 600;
  margin: 32px 0 8px;
}

.article p {
  margin: 0 0 16px;
  color: var(--text);
}

.article ul,
.article ol {
  padding-left: 24px;
  margin: 0 0 16px;
}

.article li {
  margin-bottom: 8px;
  color: var(--text);
}

.article .updated {
  color: var(--text-tertiary);
  font-size: 13px;
  margin: 0 0 32px;
}

.article section {
  margin-bottom: 8px;
}

a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.15s ease;
}

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

.breadcrumb {
  font-size: 13px;
  color: var(--text-tertiary);
  margin: 0 0 32px;
}

.breadcrumb a {
  color: var(--text-secondary);
}

.links {
  display: flex;
  gap: 32px;
  justify-content: center;
  margin: 48px 0 24px;
}

.links a {
  font-size: 15px;
}

footer {
  margin-top: 64px;
  padding-top: 32px;
  border-top: 1px solid var(--line);
  color: var(--text-tertiary);
  font-size: 13px;
  text-align: center;
}

footer p {
  margin: 0 0 16px;
}

.contact {
  background: var(--accent-soft);
  padding: 16px 20px;
  border-radius: 12px;
  border: 1px solid var(--line);
}

strong {
  color: var(--text);
  font-weight: 600;
}