:root {
  --accent: #216654;
  --accent-light: #e8f3ee;
  --accent-text: #17483b;
  --bg: #f7f7f5;
  --surface: #ffffff;
  --text: #1d211e;
  --text-secondary: #5f6660;
  --border: rgba(0, 0, 0, 0.08);
  --shadow: 0 4px 20px rgba(0, 0, 0, 0.04);
  --radius: 16px;
  --radius-sm: 8px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --accent: #7dcca3;
    --accent-light: #182820;
    --accent-text: #a5e0c1;
    --bg: #121714;
    --surface: #1a221d;
    --text: #e6eae7;
    --text-secondary: #9aa39c;
    --border: rgba(255, 255, 255, 0.08);
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
  }
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Hiragino Sans", "Hiragino Kaku Gothic ProN", Meiryo, sans-serif;
  background-color: var(--bg);
  color: var(--text);
  line-height: 1.75;
  padding: 32px 16px 64px;
}

.container {
  max-width: 720px;
  margin: 0 auto;
}

header {
  margin-bottom: 32px;
  text-align: center;
}

.app-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--accent-light);
  color: var(--accent-text);
  padding: 6px 14px;
  border-radius: 999px;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 16px;
}

h1 {
  font-size: 1.85rem;
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--text);
  letter-spacing: -0.02em;
}

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

nav {
  display: flex;
  justify-content: center;
  gap: 12px;
  margin-top: 20px;
  flex-wrap: wrap;
}

nav a, .btn-link {
  display: inline-block;
  text-decoration: none;
  color: var(--accent);
  background: var(--surface);
  border: 1px solid var(--border);
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  font-weight: 500;
  transition: all 0.2s ease;
}

nav a:hover, .btn-link:hover {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px 24px;
  margin-bottom: 20px;
  box-shadow: var(--shadow);
}

h2 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 14px;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 8px;
}

h2::before {
  content: "";
  display: inline-block;
  width: 4px;
  height: 1.1em;
  background-color: var(--accent);
  border-radius: 2px;
}

p {
  margin-bottom: 14px;
  color: var(--text);
  font-size: 0.95rem;
}

p:last-child {
  margin-bottom: 0;
}

ul, ol {
  margin-left: 20px;
  margin-bottom: 14px;
  font-size: 0.95rem;
}

li {
  margin-bottom: 6px;
}

.highlight-box {
  background: var(--accent-light);
  border-left: 4px solid var(--accent);
  padding: 16px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 18px 0;
}

.highlight-box p {
  color: var(--text);
  font-weight: 500;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  width: 100%;
  background: var(--accent);
  color: #ffffff;
  text-decoration: none;
  padding: 14px 24px;
  border-radius: 12px;
  font-weight: 600;
  font-size: 1rem;
  margin-top: 12px;
  transition: opacity 0.2s ease;
  border: none;
  cursor: pointer;
}

.btn-primary:hover {
  opacity: 0.9;
}

footer {
  margin-top: 48px;
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-secondary);
}