:root {
  --container-width: 720px;

  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 24px;
  --space-6: 32px;
  --space-7: 48px;
  --space-8: 64px;

  --font-family:
    -apple-system,
    BlinkMacSystemFont,
    "SF Pro Text",
    "Inter",
    "Segoe UI",
    Roboto,
    Helvetica,
    Arial,
    sans-serif;

  --bg: #ffffff;
  --text: #1d1d1f;
  --muted: #6e6e73;
  --accent: #2563eb;
  --border: #e5e7eb;
}

/* Reset */
* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: var(--font-family);
  font-size: 18px;
  line-height: 1.75;
  background: var(--bg);
  color: var(--text);
}

/* Layout */
.container {
  max-width: var(--container-width);
  margin: 80px auto;
  padding: 0 20px;
}

/* Header */
header {
  position: sticky;
  top: 0;
  background: rgba(255,255,255,0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  padding: 14px 40px;
  z-index: 1000;
}

header a {
  margin-right: 24px;
  text-decoration: none;
  color: var(--text);
  font-weight: 500;
  letter-spacing: -0.01em;
}

header a:hover {
  opacity: 0.7;
}

/* Typography */
h1 {
  font-size: clamp(2.4rem, 4.8vw, 3.2rem);
  font-weight: 600;
  letter-spacing: -0.025em;
  line-height: 1.15;
  margin-bottom: 20px;
}

h2 {
  font-size: 1.8rem;
  margin-top: 56px;
  margin-bottom: 14px;
  font-weight: 600;
}

h3 {
  font-size: 1.4rem;
  margin-top: 40px;
  margin-bottom: 10px;
  font-weight: 600;
}

p {
  margin-bottom: 20px;
  color: #2c2c2e;
}

/* Article */
.article {
  margin-top: 24px;
}

.article-content p {
  font-size: 19px;
  line-height: 1.75;
}

/* Metadata */
.article-meta {
  font-size: 14px;
  color: var(--muted);
  margin-bottom: 28px;
}

/* Related Articles */
.related {
  border-top: 1px solid var(--border);
  margin-top: 60px;
  padding-top: 24px;
}

.related h2 {
  margin-top: 0;
}

.related ul {
  padding-left: 18px;
}

.related li {
  margin-bottom: 8px;
}

/* Lists */
ul {
  padding-left: 18px;
}

li {
  margin-bottom: 8px;
}

/* Footer */
footer {
  margin-top: 80px;
  padding: 40px 0;
  font-size: 14px;
  color: var(--muted);
  border-top: 1px solid var(--border);
}

.article-content {
  max-width: 680px;
  margin: 0 auto;
}

.article-content h2 {
  border-top: 1px solid var(--border);
  padding-top: 32px;
  margin-top: 64px;
}

.article-content p {
  font-size: 19px;
  line-height: 1.8;
  letter-spacing: -0.003em;
}

.pillar-link {
  font-size: 14px;
  color: var(--muted);
  margin-bottom: 24px;
}    

.pillar-link a {
  color:var(--accent);
  text-decoration:none;
}

.pillar-link a:hover {
  text-decoration:underline;
}