:root {
  --mint: #00E5A5;
  --mint-dark: #00B884;
  --ink: #0E1116;
  --paper: #F6F6F2;
  --muted: #6E7480;
  --border: #E4E4DE;
  --max-w: 720px;
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Inter, Roboto, "Helvetica Neue", Arial, sans-serif;
  font-size: 17px;
  line-height: 1.55;
  color: var(--ink);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

header {
  background: var(--ink);
  color: var(--paper);
  padding: 18px 20px;
  border-bottom: 4px solid var(--mint);
}

header .wrap {
  max-width: var(--max-w);
  margin: 0 auto;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

header .brand {
  font-weight: 700;
  font-size: 18px;
  letter-spacing: 0.02em;
  text-decoration: none;
  color: var(--paper);
}

header .brand .seven {
  color: var(--mint);
}

header nav a {
  color: var(--paper);
  text-decoration: none;
  margin-left: 18px;
  font-size: 14px;
  opacity: 0.85;
}

header nav a:hover { opacity: 1; color: var(--mint); }

main {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 36px 20px 80px;
}

h1 {
  font-size: 32px;
  line-height: 1.15;
  margin: 0 0 8px;
  letter-spacing: -0.01em;
}

h2 {
  font-size: 22px;
  line-height: 1.25;
  margin: 40px 0 12px;
  letter-spacing: -0.005em;
}

h3 {
  font-size: 17px;
  line-height: 1.3;
  margin: 24px 0 8px;
  color: var(--ink);
}

.subtitle {
  color: var(--muted);
  font-size: 14px;
  margin: 0 0 28px;
}

p, ul, ol { margin: 0 0 14px; }

ul, ol { padding-left: 22px; }

li { margin-bottom: 6px; }

a { color: var(--mint-dark); }
a:hover { color: var(--ink); }

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 15px;
  margin: 14px 0 22px;
}

th, td {
  text-align: left;
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}

th {
  background: rgba(0, 229, 165, 0.08);
  font-weight: 600;
}

code {
  background: rgba(14, 17, 22, 0.06);
  padding: 2px 6px;
  border-radius: 4px;
  font-family: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.92em;
}

.note {
  background: rgba(255, 210, 74, 0.18);
  border-left: 3px solid #FFD24A;
  padding: 12px 16px;
  margin: 18px 0;
  border-radius: 0 6px 6px 0;
  font-size: 15px;
}

.cards {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
  margin: 28px 0;
}

@media (min-width: 560px) {
  .cards { grid-template-columns: 1fr 1fr; }
}

.card {
  display: block;
  padding: 22px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: #fff;
  text-decoration: none;
  color: var(--ink);
  transition: transform 0.12s ease, border-color 0.12s ease;
}

.card:hover {
  transform: translateY(-2px);
  border-color: var(--mint);
}

.card h3 { margin: 0 0 6px; color: var(--ink); }
.card p { margin: 0; color: var(--muted); font-size: 14px; }

footer {
  border-top: 1px solid var(--border);
  padding: 28px 20px;
  font-size: 13px;
  color: var(--muted);
  text-align: center;
}

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