/* === Reset & Base === */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

/* === Light theme === */
:root {
  --bg: #f0f0ec;
  --bg-card: #ffffff;
  --text: #1c1917;
  --text-muted: #6b7280;
  --accent: #166534;
  --accent-hover: #14532d;
  --accent-text: #fff;
  --border: #e5e7eb;
  --code-bg: #f3f4f6;
  --code-text: #1f2937;
  --green: #16a34a;
  --red: #dc2626;
  --radius: 6px;
  --max-width: 860px;
  --font-mono: "SF Mono", "Fira Code", "Fira Mono", "Roboto Mono", Menlo, Consolas, monospace;
}

/* === Dark forest theme — explicit === */
:root[data-theme="dark"] {
  --bg: #0b1210;
  --bg-card: #121e1a;
  --text: #dce5df;
  --text-muted: #7d9485;
  --accent: #4ade80;
  --accent-hover: #22c55e;
  --accent-text: #0b1210;
  --border: #1e3228;
  --code-bg: #0f1a16;
  --code-text: #c6d8cd;
  --green: #4ade80;
  --red: #f87171;
}

/* === Dark forest theme — system preference === */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0b1210;
    --bg-card: #121e1a;
    --text: #dce5df;
    --text-muted: #7d9485;
    --accent: #4ade80;
    --accent-hover: #22c55e;
    --accent-text: #0b1210;
    --border: #1e3228;
    --code-bg: #0f1a16;
    --code-text: #c6d8cd;
    --green: #4ade80;
    --red: #f87171;
  }
}

html {
  font-size: 16px;
  line-height: 1.6;
  color: var(--text);
  background: var(--bg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

main {
  flex: 1;
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

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

code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  background: var(--code-bg);
  color: var(--code-text);
  padding: 0.15em 0.35em;
  border-radius: 3px;
}

pre {
  background: var(--code-bg);
  color: var(--code-text);
  border: 1px solid var(--border);
  padding: 1rem 1.25rem;
  border-radius: var(--radius);
  overflow-x: auto;
  line-height: 1.5;
}
pre code {
  background: none;
  padding: 0;
  font-size: 0.875rem;
}

h1, h2, h3, h4 {
  line-height: 1.3;
}

/* === Nav === */
.site-nav {
  border-bottom: 1px solid var(--border);
  background: var(--bg);
  position: sticky;
  top: 0;
  z-index: 10;
}

.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0.75rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
}

.nav-logo {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--text);
}
.nav-logo:hover {
  text-decoration: none;
  color: var(--accent);
}

.nav-right {
  display: flex;
  align-items: center;
  gap: 1.25rem;
}

.nav-links {
  display: flex;
  gap: 1.25rem;
  font-size: 0.9rem;
}
.nav-links a {
  color: var(--text-muted);
}
.nav-links a:hover {
  color: var(--text);
  text-decoration: none;
}

/* Theme switcher */
.theme-switcher {
  display: flex;
  gap: 0.25rem;
}

.theme-btn {
  width: 1.75rem;
  height: 1.75rem;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: none;
  color: var(--text-muted);
  font-size: 0.85rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: color 0.15s, border-color 0.15s, background 0.15s;
  padding: 0;
  line-height: 1;
}

.theme-btn:hover {
  color: var(--text);
  border-color: var(--text-muted);
}

.theme-btn.active {
  color: var(--accent-text);
  background: var(--accent);
  border-color: var(--accent);
}

/* === Footer === */
.site-footer {
  border-top: 1px solid var(--border);
  margin-top: 3rem;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1.5rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  text-align: center;
}

/* === Buttons === */
.btn {
  display: inline-block;
  padding: 0.5rem 1.25rem;
  border-radius: var(--radius);
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  border: 1px solid transparent;
  text-decoration: none;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
}
.btn:hover {
  text-decoration: none;
}
.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn-primary {
  background: var(--accent);
  color: var(--accent-text);
  border-color: var(--accent);
}
.btn-primary:hover:not(:disabled) {
  background: var(--accent-hover);
  border-color: var(--accent-hover);
}

.btn-secondary {
  background: transparent;
  color: var(--accent);
  border-color: var(--accent);
}
.btn-secondary:hover:not(:disabled) {
  background: var(--accent);
  color: var(--accent-text);
}

.btn-ghost {
  background: transparent;
  color: var(--text-muted);
  border-color: var(--border);
}
.btn-ghost:hover:not(:disabled) {
  border-color: var(--text-muted);
  color: var(--text);
}

/* === Hero === */
.hero {
  text-align: center;
  padding: 3rem 0 2rem;
}

.hero h1 {
  font-family: var(--font-mono);
  font-size: 2.5rem;
  font-weight: 800;
  letter-spacing: -0.02em;
}

.tagline {
  font-size: 1.25rem;
  color: var(--accent);
  margin-top: 0.5rem;
  font-weight: 500;
}

.subtitle {
  margin-top: 0.75rem;
  color: var(--text-muted);
  max-width: 520px;
  margin-left: auto;
  margin-right: auto;
}

.hero-actions {
  margin-top: 1.5rem;
  display: flex;
  gap: 0.75rem;
  justify-content: center;
}

/* === Features === */
.features, .example-section, .install-section {
  margin-top: 3rem;
}

.features h2, .example-section h2, .install-section h2 {
  font-size: 1.4rem;
  margin-bottom: 1rem;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
}

@media (max-width: 600px) {
  .feature-grid {
    grid-template-columns: 1fr;
  }
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
}

.feature-card h3 {
  font-size: 1rem;
  margin-bottom: 0.4rem;
  color: var(--accent);
}

.feature-card p {
  font-size: 0.9rem;
  color: var(--text-muted);
}

/* === Example Table === */
.example-table {
  overflow-x: auto;
}

.example-table table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}

.example-table th,
.example-table td {
  padding: 0.5rem 0.75rem;
  text-align: left;
  border-bottom: 1px solid var(--border);
}

.example-table th {
  font-weight: 600;
  color: var(--text-muted);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* === Install === */
.install-block {
  margin-bottom: 1rem;
}

.install-example {
  margin-top: 0.5rem;
}

/* === Playground === */
.playground-section h1 {
  font-size: 1.8rem;
  margin-bottom: 0.25rem;
}

.playground-section > p {
  color: var(--text-muted);
  margin-bottom: 1.5rem;
}

.playground-input {
  margin-bottom: 1.5rem;
}

.playground-input label,
.playground-pane label {
  font-weight: 600;
  font-size: 0.8rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.playground-input label {
  display: block;
  margin-bottom: 0.35rem;
}

.pane-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.35rem;
}

.use-as-input {
  font-size: 0.75rem;
  color: var(--accent);
  background: none;
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 0.15rem 0.5rem;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s;
}
.use-as-input:hover {
  border-color: var(--accent);
  background: var(--bg-card);
}

.playground-input textarea,
.playground-pane textarea {
  width: 100%;
  font-family: var(--font-mono);
  font-size: 0.95rem;
  padding: 0.75rem 1rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-card);
  color: var(--text);
  resize: vertical;
  line-height: 1.5;
}

.playground-input textarea:focus {
  outline: 2px solid var(--accent);
  outline-offset: -1px;
  border-color: var(--accent);
}

.playground-pane textarea {
  color: var(--text-muted);
}

.input-props {
  margin-top: 0.5rem;
  font-size: 0.85rem;
}

.prop {
  color: var(--text-muted);
}

.prop-val {
  font-family: var(--font-mono);
  font-weight: 600;
}
.prop-val.yes { color: var(--green); }
.prop-val.no { color: var(--red); }

.playground-outputs {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

@media (max-width: 600px) {
  .playground-outputs {
    grid-template-columns: 1fr;
  }
}

.playground-pane {
  position: relative;
}

.pane-body {
  position: relative;
}

.pane-overlay {
  display: none;
  position: absolute;
  inset: 0;
  border-radius: var(--radius);
  border: 1px dashed var(--border);
  background: var(--bg);
  color: var(--text-muted);
  font-size: 0.9rem;
  align-items: center;
  justify-content: center;
}

.playground-pane.inactive .pane-overlay {
  display: flex;
}

.playground-pane.inactive textarea {
  visibility: hidden;
}

.playground-pane.inactive .use-as-input {
  display: none;
}

.wasm-loading {
  color: var(--text-muted);
  font-size: 0.9rem;
  padding: 1rem 0;
}
.wasm-error {
  color: var(--red);
  font-size: 0.9rem;
}

/* === Spec/Docs page === */
.doc-page h1 {
  margin-bottom: 0.5rem;
}

.doc-page h2 {
  margin-top: 2rem;
  margin-bottom: 0.5rem;
  font-size: 1.4rem;
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.35rem;
}

.doc-page h3 {
  margin-top: 1.5rem;
  margin-bottom: 0.4rem;
  font-size: 1.1rem;
}

.doc-page h4 {
  margin-top: 1.25rem;
  margin-bottom: 0.3rem;
  font-size: 1rem;
}

.doc-page p {
  margin-top: 0.5rem;
}

.doc-page ul, .doc-page ol {
  margin-top: 0.5rem;
  padding-left: 1.5rem;
}

.doc-page li {
  margin-top: 0.25rem;
}

.doc-page table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 0.75rem;
  font-size: 0.9rem;
}

.doc-page th, .doc-page td {
  padding: 0.5rem 0.75rem;
  text-align: left;
  border: 1px solid var(--border);
}

.doc-page th {
  background: var(--code-bg);
  font-weight: 600;
}

.doc-page blockquote {
  border-left: 3px solid var(--accent);
  padding-left: 1rem;
  color: var(--text-muted);
  margin-top: 0.75rem;
}

/* Heading anchor links */
.doc-page h2 a.header-anchor,
.doc-page h3 a.header-anchor,
.doc-page h4 a.header-anchor {
  color: var(--text-muted);
  text-decoration: none;
  margin-left: 0.35em;
  opacity: 0;
  font-weight: 400;
  transition: opacity 0.15s;
}

.doc-page h2:hover a.header-anchor,
.doc-page h3:hover a.header-anchor,
.doc-page h4:hover a.header-anchor {
  opacity: 0.6;
}

.doc-page h2 a.header-anchor:hover,
.doc-page h3 a.header-anchor:hover,
.doc-page h4 a.header-anchor:hover {
  opacity: 1;
  color: var(--accent);
}

/* === Decision Tree === */
.decision-tree {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  line-height: 1.8;
}

.dt-question {
  color: var(--syn-function);
  font-weight: 600;
}

.dt-yes {
  color: var(--green);
  font-weight: 600;
}

.dt-no {
  color: var(--red);
  font-weight: 600;
}

.dt-string {
  color: var(--syn-string);
}

.dt-note {
  color: var(--text-muted);
  font-style: italic;
}

/* === Responsive === */
@media (max-width: 600px) {
  .hero h1 {
    font-size: 2rem;
  }

  .hero-actions {
    flex-direction: column;
    align-items: center;
  }

  .site-nav {
    position: relative;
  }

  .nav-inner {
    flex-direction: column;
    gap: 0.5rem;
  }

  .theme-switcher {
    position: absolute;
    top: 0.75rem;
    right: 1.5rem;
    gap: 0.15rem;
  }

  .theme-btn {
    width: 1.4rem;
    height: 1.4rem;
    font-size: 0.7rem;
  }

  .playground-props {
    flex-direction: column;
  }
}