:root {
  --bg: #ffffff;
  --bg-raised: #f6f7f9;
  --border: #e3e5e9;
  --text: #1a1d23;
  --text-dim: #5b616e;
  --accent: #0060df;
  --accent-bg: #eaf1fd;
  --code-bg: #f6f7f9;
  --code-text: #24292e;
  --tag-bg: #eef1f5;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0d1117;
    --bg-raised: #151b23;
    --border: #2a313c;
    --text: #e6e8eb;
    --text-dim: #9aa2ad;
    --accent: #6ea8fe;
    --accent-bg: #16233b;
    --code-bg: #151b23;
    --code-text: #d7dbe0;
    --tag-bg: #1c2330;
  }
}

* {
  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;
  line-height: 1.55;
  overflow-x: hidden;
}

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

a:hover {
  text-decoration: underline;
}

code, pre {
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}

.wrap {
  max-width: 920px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Nav */
nav {
  border-bottom: 1px solid var(--border);
  padding: 18px 0;
}

nav .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

.brand {
  font-weight: 700;
  font-size: 15px;
  color: var(--text);
  letter-spacing: -0.01em;
}

.brand:hover {
  text-decoration: none;
  color: var(--accent);
}

.nav-links {
  display: flex;
  gap: 20px;
  font-size: 14px;
}

.nav-links a {
  color: var(--text-dim);
}

.nav-links a:hover {
  color: var(--accent);
}

/* Hero */
header.hero {
  padding: 64px 0 40px;
}

.badge {
  display: inline-block;
  font-size: 12px;
  font-weight: 600;
  color: var(--accent);
  background: var(--accent-bg);
  border-radius: 100px;
  padding: 4px 12px;
  margin-bottom: 20px;
  letter-spacing: 0.02em;
}

h1 {
  font-size: clamp(28px, 4.5vw, 40px);
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin: 0 0 16px;
}

.lede {
  font-size: 18px;
  color: var(--text-dim);
  max-width: 640px;
  margin: 0 0 28px;
}

.cta-row {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.btn {
  display: inline-block;
  padding: 10px 18px;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 600;
  border: 1px solid var(--border);
}

.btn:hover {
  text-decoration: none;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

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

.btn-secondary {
  color: var(--text);
  background: var(--bg-raised);
}

.btn-secondary:hover {
  border-color: var(--accent);
}

/* Sections */
section {
  padding: 40px 0;
  border-top: 1px solid var(--border);
}

h2 {
  font-size: 22px;
  letter-spacing: -0.01em;
  margin: 0 0 12px;
}

section > p {
  color: var(--text-dim);
  max-width: 700px;
}

/* Contract cards */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 16px;
  margin-top: 24px;
}

.card {
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px;
  background: var(--bg-raised);
}

.card h3 {
  margin: 0 0 8px;
  font-size: 16px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.card p {
  margin: 0 0 14px;
  font-size: 14px;
  color: var(--text-dim);
}

.tag {
  display: inline-block;
  font-size: 11px;
  font-weight: 600;
  color: var(--text-dim);
  background: var(--tag-bg);
  border-radius: 6px;
  padding: 2px 8px;
  margin: 2px 4px 2px 0;
}

.card .fns {
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px solid var(--border);
}

.card .fns code {
  display: block;
  font-size: 12.5px;
  color: var(--code-text);
  margin-bottom: 4px;
}

/* Architecture diagram */
.flow {
  margin-top: 24px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--bg-raised);
  padding: 24px;
  font-size: 13.5px;
  overflow-x: auto;
}

.flow pre {
  margin: 0;
  color: var(--code-text);
  white-space: pre;
}

/* Code blocks */
pre.code {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 16px 18px;
  overflow-x: auto;
  font-size: 13px;
  color: var(--code-text);
  margin: 8px 0 16px;
}

pre.code .comment {
  color: var(--text-dim);
}

/* Footer */
footer {
  padding: 32px 0 60px;
  border-top: 1px solid var(--border);
  font-size: 13px;
  color: var(--text-dim);
}

footer a {
  color: var(--text-dim);
  text-decoration: underline;
}

footer .foot-row {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
}