/* ---------- tokens ---------- */
:root {
  --bg: #12151b;
  --bg-elevated: #191d25;
  --bg-terminal: #14171d;
  --border: #2a303c;
  --border-soft: #21252f;
  --text: #edebe6;
  --text-muted: #8d93a6;
  --text-faint: #5b6274;

  --accent: #c9a15c;
  --accent-soft: rgba(201, 161, 92, 0.12);

  --patch: #5b8def;
  --patch-soft: rgba(91, 141, 239, 0.12);
  --minor: #4fb477;
  --minor-soft: rgba(79, 180, 119, 0.12);
  --major: #e5484d;
  --major-soft: rgba(229, 72, 77, 0.12);

  --font-mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --font-sans: 'IBM Plex Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

  --radius: 10px;
  --max-width: 860px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  background-image:
    radial-gradient(circle at 15% 0%, rgba(91, 141, 239, 0.06), transparent 40%),
    radial-gradient(circle at 85% 10%, rgba(201, 161, 92, 0.05), transparent 45%);
  color: var(--text);
  font-family: var(--font-sans);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

h1,
h2,
h3 {
  font-family: var(--font-mono);
  margin: 0;
}

p {
  margin: 0;
}

ul {
  margin: 0;
  padding: 0;
  list-style: none;
}

a {
  color: inherit;
}

code {
  font-family: var(--font-mono);
}

.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--accent);
  color: #14171d;
  padding: 0.5rem 1rem;
  z-index: 100;
}

.skip-link:focus {
  left: 1rem;
  top: 1rem;
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: 3px;
}

/* ---------- topbar ---------- */
.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  gap: 1.5rem;
  padding: 0.9rem 1.5rem;
  background: rgba(18, 21, 27, 0.85);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-soft);
}

.brand {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 0.95rem;
  text-decoration: none;
  white-space: nowrap;
}

.brand-mark {
  color: var(--accent);
}

.brand-rest {
  color: var(--text-muted);
  font-weight: 400;
}

.topnav {
  display: flex;
  gap: 1.25rem;
  overflow-x: auto;
  scrollbar-width: none;
  flex: 1;
}

.topnav::-webkit-scrollbar {
  display: none;
}

.topnav a {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text-muted);
  text-decoration: none;
  white-space: nowrap;
  padding: 0.25rem 0;
  border-bottom: 1px solid transparent;
  transition: color 0.15s, border-color 0.15s;
}

.topnav a:hover {
  color: var(--text);
  border-color: var(--accent);
}

.spec-link {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-muted);
  text-decoration: none;
  white-space: nowrap;
  border: 1px solid var(--border);
  padding: 0.4rem 0.75rem;
  border-radius: 999px;
  transition: border-color 0.15s, color 0.15s;
}

.spec-link:hover {
  color: var(--accent);
  border-color: var(--accent);
}

.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 0.25rem;
  padding: 0.35rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: transparent;
  cursor: pointer;
}

.menu-toggle span {
  display: block;
  width: 1.15rem;
  height: 2px;
  background: var(--text-muted);
  border-radius: 999px;
}

.menu-toggle:hover span {
  background: var(--accent);
}

/* ---------- layout ---------- */
main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.section {
  padding: 3.5rem 0;
  border-bottom: 1px solid var(--border-soft);
}

.section:last-of-type {
  border-bottom: none;
}

.eyebrow {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--accent);
  letter-spacing: 0.02em;
  margin-bottom: 0.75rem;
}

.eyebrow::after {
  content: '';
  display: inline-block;
  width: 7px;
  height: 1em;
  vertical-align: -2px;
  margin-left: 5px;
  background: var(--accent);
  animation: blink 1.1s steps(1) infinite;
}

@keyframes blink {
  50% {
    opacity: 0;
  }
}

h2 {
  font-size: clamp(1.4rem, 3vw, 1.8rem);
  margin-bottom: 1.25rem;
}

.subhead {
  font-size: 0.85rem;
  color: var(--text-muted);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin: 2rem 0 1rem;
}

.subhead:first-of-type {
  margin-top: 0;
}

.footnote {
  color: var(--text-faint);
  font-size: 0.85rem;
  margin-top: 1rem;
}

/* ---------- hero ---------- */
.hero {
  padding: 4.5rem 0 3rem;
}

.hero h1 {
  font-size: clamp(2.1rem, 5.5vw, 3.4rem);
  line-height: 1.15;
  font-weight: 700;
  letter-spacing: -0.01em;
  margin-bottom: 1.25rem;
}

.hero-sub {
  max-width: 560px;
  color: var(--text-muted);
  font-size: 1.05rem;
  margin-bottom: 2.5rem;
}

.anatomy {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem 1.5rem 1.25rem;
  overflow-x: auto;
}

.anatomy-row {
  display: flex;
  align-items: flex-start;
  gap: 0.4rem;
  font-family: var(--font-mono);
  font-size: clamp(1rem, 2.6vw, 1.3rem);
  white-space: nowrap;
}

.part {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.6rem;
}

.part.grow {
  flex: 1;
  min-width: 0;
}

.part .lbl {
  font-family: var(--font-sans);
  font-size: 0.7rem;
  color: var(--text-faint);
  white-space: nowrap;
}

.part .lbl em {
  font-style: normal;
  color: var(--text-faint);
}

.tok {
  border-bottom: 2px solid transparent;
  padding-bottom: 2px;
}

.tok.type {
  color: var(--minor);
  border-color: var(--minor);
}

.tok.scope {
  color: var(--patch);
  border-color: var(--patch);
}

.tok.bang {
  color: var(--major);
  border-color: var(--major);
  font-weight: 700;
}

.tok.desc {
  color: var(--text);
  border-color: var(--border);
  white-space: normal;
}

.tok.punct {
  color: var(--text-faint);
}

.hero-note {
  margin-top: 1.25rem;
  color: var(--text-faint);
  font-size: 0.85rem;
  font-family: var(--font-mono);
}

/* ---------- terminal / code blocks ---------- */
.terminal {
  background: var(--bg-terminal);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  margin-bottom: 1.25rem;
  transition: border-color 0.15s, transform 0.15s;
}

.terminal:hover {
  border-color: var(--border-soft);
}

.terminal-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.6rem 0.9rem;
  border-bottom: 1px solid var(--border-soft);
  background: rgba(255, 255, 255, 0.015);
}

.prompt-path {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-faint);
}

.branch {
  color: var(--accent);
  margin-left: 0.4rem;
}

.copy-btn {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-muted);
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.3rem 0.6rem;
  cursor: pointer;
  transition: color 0.15s, border-color 0.15s;
}

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

.copy-btn.copied {
  color: var(--minor);
  border-color: var(--minor);
}

.terminal-body {
  margin: 0;
  padding: 1.1rem 1.2rem;
  font-family: var(--font-mono);
  font-size: 0.88rem;
  line-height: 1.65;
  color: var(--text);
  overflow-x: auto;
  white-space: pre;
}

/* ---------- rules list ---------- */
.rules {
  display: flex;
  flex-direction: column;
  gap: 0.7rem;
  margin-top: 1.5rem;
}

.rules li {
  padding-left: 1.1rem;
  position: relative;
  color: var(--text-muted);
  font-size: 0.95rem;
}

.rules li::before {
  content: '›';
  position: absolute;
  left: 0;
  color: var(--accent);
  font-family: var(--font-mono);
}

.rules strong {
  color: var(--text);
  font-weight: 600;
}

.rules code,
.tips-list code {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 0.05rem 0.4rem;
  font-size: 0.85em;
  color: var(--accent);
}

/* ---------- type cards ---------- */
.core-types {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
}

.type-card {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-left: 3px solid transparent;
  border-radius: var(--radius);
  padding: 1.1rem 1.1rem 1.25rem;
  transition: transform 0.15s, border-color 0.15s;
}

.type-card:hover {
  transform: translateY(-2px);
}

.card-patch {
  border-left-color: var(--patch);
}

.card-minor {
  border-left-color: var(--minor);
}

.card-major {
  border-left-color: var(--major);
}

.badge {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.05em;
  padding: 0.2rem 0.5rem;
  border-radius: 999px;
  margin-bottom: 0.75rem;
}

.card-patch .badge {
  color: var(--patch);
  background: var(--patch-soft);
}

.card-minor .badge {
  color: var(--minor);
  background: var(--minor-soft);
}

.card-major .badge {
  color: var(--major);
  background: var(--major-soft);
}

.type-name {
  display: block;
  font-size: 1.05rem;
  margin-bottom: 0.4rem;
  color: var(--text);
}

.type-card p {
  color: var(--text-muted);
  font-size: 0.87rem;
}

.type-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.8rem;
}

.mini-card {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.9rem 1rem;
  transition: transform 0.15s, border-color 0.15s;
}

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

.mini-card code {
  color: var(--accent);
  font-size: 0.92rem;
  display: block;
  margin-bottom: 0.4rem;
}

.mini-card p {
  color: var(--text-muted);
  font-size: 0.82rem;
  line-height: 1.5;
}

/* ---------- breaking changes ---------- */
.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  align-items: start;
}

.two-col .terminal {
  margin-bottom: 0;
}

/* ---------- tips ---------- */
.tips-list {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.tips-list li {
  padding-left: 1.3rem;
  position: relative;
  color: var(--text-muted);
  font-size: 0.95rem;
}

.tips-list li::before {
  content: '✓';
  position: absolute;
  left: 0;
  color: var(--minor);
  font-size: 0.8rem;
}

/* ---------- footer ---------- */
.site-footer {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2.5rem 1.5rem 4rem;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--text-faint);
}

.site-footer a {
  color: var(--text-muted);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.site-footer a:hover {
  color: var(--accent);
}

.github-link {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  text-decoration: none;
}

.github-icon {
  width: 1rem;
  height: 1rem;
  flex-shrink: 0;
}

/* ---------- responsive ---------- */
@media (max-width: 768px) {
  .topbar {
    gap: 0.9rem;
    padding: 0.8rem 1rem;
    display: grid;
    grid-template-columns: 1fr 1fr;
    grid-template-rows: auto;
  }

  .menu-toggle {
    display: inline-flex;
    margin-left: auto;
  }

  .spec-link {
    display: none;
  }

  .topnav {
    display: none;
    width: 100%;
    flex-direction: column;
    gap: 0.65rem;
    padding-top: 0.35rem;
    border-top: 1px solid var(--border-soft);
  }

  .topnav.open {
    display: flex;
    grid-column: 1 / 3;
  }

  .topnav a {
    padding: 0.2rem 0;
  }

  .core-types {
    grid-template-columns: 1fr;
  }

  .type-grid {
    grid-template-columns: 1fr 1fr;
  }

  .two-col {
    grid-template-columns: 1fr;
  }

  .anatomy-row {
    flex-wrap: wrap;
    white-space: normal;
  }
}

@media (max-width: 460px) {
  .type-grid {
    grid-template-columns: 1fr;
  }
}

/* ---------- motion ---------- */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .eyebrow::after {
    animation: none;
  }

  .terminal,
  .type-card,
  .mini-card {
    transition: none;
  }
}