:root {
  --accent: #1d6df0;
  --ink: #1a1d23;
  --muted: #5c6371;
  --line: #e2e5ea;
  --bg: #ffffff;
  --soft: #f5f6f8;
}

* { box-sizing: border-box; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", Helvetica, Arial, sans-serif;
  margin: 0;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.6;
  font-size: 16px;
}

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

/* Header / Nav */
.site-header {
  border-bottom: 1px solid var(--line);
  background: #fff;
}
.site-header .inner {
  max-width: 880px;
  margin: 0 auto;
  padding: 18px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px;
}
.brand {
  font-size: 20px;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--ink);
  text-decoration: none;
}
.brand span { color: var(--accent); }
nav a {
  text-decoration: none;
  color: var(--muted);
  font-size: 15px;
  margin-left: 18px;
}
nav a:hover, nav a.active { color: var(--ink); }

/* Main */
main {
  max-width: 760px;
  margin: 0 auto;
  padding: 40px 20px 64px;
}
h1 { font-size: 30px; letter-spacing: -0.02em; margin: 0 0 14px; }
h2 { font-size: 20px; margin: 32px 0 10px; padding-bottom: 4px; border-bottom: 2px solid var(--accent); }
h3 { font-size: 16px; margin: 18px 0 6px; }
p, li { font-size: 16px; }
ul, ol { padding-left: 22px; }
.lead { font-size: 18px; color: var(--muted); }
.meta { color: var(--muted); font-size: 13px; margin-bottom: 24px; }
code { background: var(--soft); padding: 2px 6px; border-radius: 4px; font-size: 13px; }

.hero {
  background: var(--soft);
  border-radius: 14px;
  padding: 28px;
  margin: 24px 0;
}
.highlight {
  background: #e6f5ec;
  border-left: 4px solid #1f9d55;
  padding: 12px 16px;
  border-radius: 0 6px 6px 0;
  margin: 16px 0;
}
.placeholder { background: #fff4d6; padding: 1px 6px; border-radius: 4px; }

.card-row { display: flex; flex-wrap: wrap; gap: 16px; margin: 20px 0; }
.card {
  flex: 1 1 220px;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 18px;
}
.card h3 { margin-top: 0; }

/* Footer */
.site-footer {
  border-top: 1px solid var(--line);
  margin-top: 40px;
}
.site-footer .inner {
  max-width: 880px;
  margin: 0 auto;
  padding: 24px 20px 48px;
  color: var(--muted);
  font-size: 14px;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  justify-content: space-between;
}
.site-footer a { color: var(--muted); text-decoration: none; }
.site-footer a:hover { color: var(--ink); }