:root {
  --bg: #0a0a0a;
  --fg: #f5f5f5;
  --muted: #8a8a8a;
  --line: #1f1f1f;
  --accent: #e8a87c;
  --max: 920px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Inter", system-ui, sans-serif;
  font-size: 17px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a {
  color: var(--fg);
  text-decoration: underline;
  text-decoration-color: var(--line);
  text-underline-offset: 3px;
  transition: text-decoration-color 0.15s ease;
}
a:hover { text-decoration-color: var(--accent); }

.wrap {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 32px;
}

header.site {
  padding: 28px 0;
  border-bottom: 1px solid var(--line);
}
header.site .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
}
header.site a.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  font-weight: 600;
  letter-spacing: -0.01em;
}
header.site a.brand img {
  width: 28px;
  height: 28px;
  border-radius: 6px;
}
header.site nav {
  display: flex;
  gap: 24px;
  font-size: 15px;
  color: var(--muted);
}
header.site nav a {
  color: var(--muted);
  text-decoration: none;
}
header.site nav a:hover { color: var(--fg); }

.hero {
  padding: 88px 0 72px;
  text-align: center;
}
.hero img.icon {
  width: 120px;
  height: 120px;
  border-radius: 24px;
  margin-bottom: 32px;
  box-shadow: 0 20px 60px rgba(0,0,0,0.6);
}
.hero h1 {
  font-size: 56px;
  line-height: 1.05;
  letter-spacing: -0.03em;
  font-weight: 700;
  margin: 0 0 20px;
}
.hero .tag {
  font-size: 22px;
  color: var(--muted);
  max-width: 560px;
  margin: 0 auto 36px;
  line-height: 1.4;
}
.hero .cta {
  display: inline-block;
  padding: 14px 28px;
  background: var(--fg);
  color: var(--bg);
  border-radius: 999px;
  text-decoration: none;
  font-weight: 600;
  font-size: 15px;
  letter-spacing: -0.005em;
}
.hero .cta.disabled {
  background: transparent;
  color: var(--muted);
  border: 1px solid var(--line);
  cursor: default;
}

section {
  padding: 64px 0;
  border-top: 1px solid var(--line);
}
section h2 {
  font-size: 32px;
  letter-spacing: -0.02em;
  font-weight: 600;
  margin: 0 0 8px;
}
section .sub {
  color: var(--muted);
  margin: 0 0 40px;
  font-size: 17px;
}

.features {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px 48px;
}
.feature h3 {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 600;
  letter-spacing: -0.005em;
}
.feature p {
  margin: 0;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.55;
}

.boundaries {
  background: transparent;
}
.boundaries ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px 48px;
  color: var(--muted);
  font-size: 15px;
}
.boundaries li::before {
  content: "—  ";
  color: var(--line);
}

.shortcuts .key-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 8px 0 28px;
}
.shortcuts .key-row kbd {
  font-size: 14px;
  padding: 9px 13px;
  min-width: 36px;
}
.shortcuts .more {
  margin: 0;
  font-size: 15px;
  color: var(--muted);
}
.shortcuts .more a {
  color: var(--muted);
  text-decoration: none;
}
.shortcuts .more a:hover { color: var(--fg); }

.shortcuts-page {
  padding: 64px 0 96px;
}
.shortcuts-page h1 {
  font-size: 40px;
  letter-spacing: -0.02em;
  font-weight: 700;
  margin: 0 0 8px;
}
.shortcuts-page .meta {
  color: var(--muted);
  font-size: 15px;
  max-width: 640px;
  margin: 0 0 48px;
}

.shortcut-groups {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 40px 48px;
}
.shortcut-group :is(h2, h3) {
  margin: 0 0 16px;
  font-size: 17px;
  font-weight: 600;
  letter-spacing: -0.005em;
}
.shortcut-group dl {
  margin: 0;
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 12px 20px;
  align-items: baseline;
  font-size: 15px;
}
.shortcut-group dt {
  white-space: nowrap;
  color: var(--fg);
}
.shortcut-group dd {
  margin: 0;
  color: var(--muted);
}
kbd {
  display: inline-block;
  font-family: ui-monospace, "SF Mono", Menlo, monospace;
  font-size: 12px;
  line-height: 1;
  padding: 5px 7px;
  min-width: 22px;
  text-align: center;
  background: #161616;
  border: 1px solid var(--line);
  border-radius: 5px;
  color: var(--fg);
}

footer.site {
  padding: 48px 0 80px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 14px;
}
footer.site .wrap {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
}
footer.site nav {
  display: flex;
  gap: 24px;
}
footer.site a {
  color: var(--muted);
  text-decoration: none;
}
footer.site a:hover { color: var(--fg); }

article.doc {
  padding: 64px 0 96px;
  max-width: 680px;
  margin: 0 auto;
}
article.doc h1 {
  font-size: 40px;
  letter-spacing: -0.02em;
  margin: 0 0 8px;
}
article.doc .meta {
  color: var(--muted);
  font-size: 14px;
  margin: 0 0 40px;
}
article.doc h2 {
  font-size: 22px;
  letter-spacing: -0.01em;
  margin: 40px 0 12px;
}
article.doc p, article.doc li {
  color: #c8c8c8;
  font-size: 16px;
  line-height: 1.65;
}
article.doc ul { padding-left: 20px; }

@media (max-width: 640px) {
  .hero { padding: 56px 0 48px; }
  .hero h1 { font-size: 40px; }
  .hero .tag { font-size: 18px; }
  .features, .boundaries ul, .shortcut-groups { grid-template-columns: 1fr; }
  section { padding: 48px 0; }
  article.doc h1 { font-size: 32px; }
}