:root {
  --bg: #ffffff;
  --text: #1a1a1a;
  --muted: #6b6b6b;
  --border: #e5e5e5;
  --accent: #1a1a1a;
  --callout-bg: #f6f7f9;
  --max-width: 760px;
}

* {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  font-size: 17px;
  line-height: 1.65;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
}

/* Header */
.site-header {
  border-bottom: 1px solid var(--border);
  background: var(--bg);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  padding-top: 16px;
  padding-bottom: 16px;
}

.brand {
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--text);
  text-decoration: none;
}

.nav {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.nav a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.95rem;
  padding: 6px 12px;
  border-radius: 6px;
  transition: background 0.15s ease, color 0.15s ease;
}

.nav a:hover {
  color: var(--text);
  background: var(--callout-bg);
}

.nav a.active {
  color: var(--text);
  font-weight: 600;
  background: var(--callout-bg);
}

/* Content */
.content {
  flex: 1;
  padding-top: 40px;
  padding-bottom: 60px;
}

h1 {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 0 0 4px;
}

h2 {
  font-size: 1.25rem;
  font-weight: 600;
  margin: 36px 0 8px;
}

.updated {
  color: var(--muted);
  font-size: 0.9rem;
  margin: 0 0 28px;
}

p {
  margin: 0 0 16px;
}

ul {
  margin: 0 0 16px;
  padding-left: 22px;
}

li {
  margin-bottom: 8px;
}

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

.content a {
  text-decoration: underline;
  text-underline-offset: 2px;
}

.callout {
  background: var(--callout-bg);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: 8px;
  padding: 16px 18px;
  margin: 0 0 28px;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.875rem;
  padding: 24px 0;
}

.site-footer p {
  margin: 4px 0;
}

.site-footer a {
  color: var(--muted);
}

/* Responsive */
@media (max-width: 600px) {
  body {
    font-size: 16px;
  }
  h1 {
    font-size: 1.6rem;
  }
  .header-inner {
    flex-direction: column;
    align-items: flex-start;
  }
  .content {
    padding-top: 28px;
  }
}