:root {
  --bg: #0d1117;
  --bg2: #161b22;
  --bg3: #21262d;
  --border: #30363d;
  --text: #e6edf3;
  --text2: #8b949e;
  --accent: #e6873a;
  --accent2: #58a6ff;
  --green: #3fb950;
  --purple: #a371f7;
  --red: #f85149;
  --yellow: #d29922;
  --cyan: #39d353;
  --code-bg: #161b22;
  --tag-bg: #21262d;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { font-size: 15px; scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  line-height: 1.6;
  min-height: 100vh;
}

/* Nav */
nav {
  background: var(--bg2);
  border-bottom: 1px solid var(--border);
  padding: 0 1rem;
  display: flex;
  align-items: center;
  gap: 0;
  overflow-x: auto;
  scrollbar-width: none;
  position: sticky;
  top: 0;
  z-index: 100;
}
nav::-webkit-scrollbar { display: none; }
.nav-brand {
  font-weight: 700;
  color: var(--accent);
  white-space: nowrap;
  padding: 0.75rem 1rem 0.75rem 0;
  border-right: 1px solid var(--border);
  margin-right: 0.5rem;
  font-size: 0.95rem;
}
nav a {
  color: var(--text2);
  text-decoration: none;
  padding: 0.75rem 0.7rem;
  font-size: 0.85rem;
  white-space: nowrap;
  border-bottom: 2px solid transparent;
  transition: color 0.15s, border-color 0.15s;
}
nav a:hover { color: var(--text); }
nav a.active { color: var(--accent2); border-bottom-color: var(--accent2); }

/* Main layout */
main {
  max-width: 900px;
  margin: 0 auto;
  padding: 1.5rem 1rem 3rem;
}

/* Page header */
.page-header {
  margin-bottom: 1.5rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border);
}
.page-header h1 {
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 0.3rem;
}
.page-header p {
  color: var(--text2);
  font-size: 0.9rem;
}

/* Section cards */
details {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: 8px;
  margin-bottom: 1rem;
  overflow: hidden;
}

summary {
  cursor: pointer;
  padding: 0.85rem 1rem;
  font-weight: 600;
  font-size: 0.95rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  list-style: none;
  user-select: none;
  background: var(--bg2);
  border-bottom: 1px solid transparent;
  transition: background 0.15s;
}
summary::-webkit-details-marker { display: none; }
details[open] summary {
  border-bottom-color: var(--border);
  background: var(--bg3);
}
summary:hover { background: var(--bg3); }

.summary-arrow {
  display: inline-block;
  width: 1.1rem;
  text-align: center;
  font-size: 0.75rem;
  color: var(--text2);
  transition: transform 0.2s;
}
details[open] .summary-arrow { transform: rotate(90deg); }

.summary-icon {
  font-size: 1rem;
  width: 1.3rem;
  text-align: center;
}

.section-body {
  padding: 1rem;
}

/* Flow diagram */
.flow-diagram {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 1rem;
  margin: 0.75rem 0;
  overflow-x: auto;
}
.flow-diagram pre {
  white-space: pre;
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  font-size: 0.8rem;
  color: var(--cyan);
  line-height: 1.4;
}

/* Code blocks */
.code-block {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.85rem 1rem;
  margin: 0.6rem 0;
  overflow-x: auto;
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  font-size: 0.8rem;
  line-height: 1.5;
  white-space: pre;
  color: var(--text);
}

.code-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.3rem;
}
.code-label {
  font-size: 0.75rem;
  color: var(--text2);
  font-family: "SFMono-Regular", Consolas, monospace;
}

/* GitHub link */
.gh-link {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  color: var(--accent2);
  text-decoration: none;
  font-size: 0.78rem;
  font-family: "SFMono-Regular", Consolas, monospace;
  background: var(--tag-bg);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 0.15rem 0.5rem;
  transition: background 0.15s;
}
.gh-link:hover { background: var(--bg3); color: var(--text); }
.gh-link::before { content: "⟨⟩"; font-size: 0.7rem; }

/* Inline code */
code {
  background: var(--tag-bg);
  border: 1px solid var(--border);
  border-radius: 3px;
  padding: 0.1em 0.35em;
  font-family: "SFMono-Regular", Consolas, monospace;
  font-size: 0.85em;
  color: var(--purple);
}

/* Descriptions */
p { margin: 0.5rem 0; color: var(--text); font-size: 0.9rem; }
h2 { font-size: 1.1rem; color: var(--text); margin: 0.75rem 0 0.4rem; }
h3 { font-size: 0.95rem; color: var(--text2); margin: 0.6rem 0 0.3rem; font-weight: 600; }

/* Tags / badges */
.tag {
  display: inline-block;
  font-size: 0.72rem;
  padding: 0.1em 0.5em;
  border-radius: 20px;
  font-weight: 600;
  vertical-align: middle;
  margin-left: 0.3rem;
}
.tag-write { background: #0d2d0d; color: var(--green); border: 1px solid #1a4d1a; }
.tag-read  { background: #0d1d2d; color: var(--accent2); border: 1px solid #1a3a4d; }
.tag-async { background: #2d2208; color: var(--yellow); border: 1px solid #4d3a10; }
.tag-interface { background: #1e0d2d; color: var(--purple); border: 1px solid #3a1a4d; }

/* Step list */
.steps { list-style: none; margin: 0.5rem 0; }
.steps li {
  padding: 0.4rem 0 0.4rem 2rem;
  position: relative;
  font-size: 0.88rem;
  color: var(--text);
  border-left: 2px solid var(--border);
  margin-left: 0.75rem;
}
.steps li + li { border-top: none; }
.steps li::before {
  content: attr(data-step);
  position: absolute;
  left: -0.85rem;
  top: 0.45rem;
  background: var(--accent);
  color: #000;
  font-size: 0.7rem;
  font-weight: 700;
  width: 1.4rem;
  height: 1.4rem;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  line-height: 1;
}

/* Props table */
.props {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.83rem;
  margin: 0.5rem 0;
}
.props th, .props td {
  text-align: left;
  padding: 0.4rem 0.6rem;
  border: 1px solid var(--border);
}
.props th {
  background: var(--bg3);
  color: var(--text2);
  font-weight: 600;
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.props td:first-child { color: var(--purple); font-family: monospace; }
.props td:last-child { color: var(--text2); }

/* Component links grid */
.component-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 0.75rem;
  margin: 0.75rem 0;
}
.component-card {
  background: var(--bg3);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.85rem;
  text-decoration: none;
  display: block;
  transition: border-color 0.15s, background 0.15s;
}
.component-card:hover { border-color: var(--accent2); background: #161b22; }
.component-card .card-icon { font-size: 1.4rem; margin-bottom: 0.3rem; }
.component-card .card-title { font-weight: 600; color: var(--text); font-size: 0.9rem; }
.component-card .card-desc { color: var(--text2); font-size: 0.78rem; margin-top: 0.2rem; }

/* Divider */
.divider {
  border: none;
  border-top: 1px solid var(--border);
  margin: 0.75rem 0;
}

/* Warning / info callout */
.callout {
  border-radius: 6px;
  padding: 0.65rem 0.9rem;
  margin: 0.6rem 0;
  font-size: 0.85rem;
  border-left: 3px solid;
}
.callout-info { background: #0d1d2d; border-color: var(--accent2); color: #aac8e4; }
.callout-warn { background: #2d2208; border-color: var(--yellow); color: #c4a84a; }

/* Responsive */
@media (max-width: 600px) {
  main { padding: 1rem 0.75rem 2rem; }
  .page-header h1 { font-size: 1.25rem; }
  .code-block { font-size: 0.75rem; }
  .component-grid { grid-template-columns: 1fr 1fr; }
}