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

:root {
  /* Palette */
  --bg-base:        #0d1117;
  --bg-surface:     #161b22;
  --bg-elevated:    #1c2128;
  --bg-hover:       #21262d;
  --border:         #30363d;
  --border-subtle:  #21262d;

  --text-primary:   #e6edf3;
  --text-secondary: #8b949e;
  --text-muted:     #484f58;

  --accent-blue:    #58a6ff;
  --accent-green:   #3fb950;
  --accent-orange:  #d29922;
  --accent-purple:  #bc8cff;
  --accent-red:     #f85149;
  --accent-teal:    #39d353;

  /* Node type colours */
  --color-umbrella:    #58a6ff;
  --color-guide:       #3fb950;
  --color-standard:    #bc8cff;
  --color-cheat-sheet: #d29922;
  --color-tool:        #f78166;
  --color-root:        #e6edf3;

  /* Layout */
  --header-height: 100px;
  --sidebar-width: 360px;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;

  /* Transitions */
  --ease: cubic-bezier(0.4, 0, 0.2, 1);
  --dur-fast: 150ms;
  --dur-med:  250ms;
  --dur-slow: 400ms;
}

html, body {
  height: 100%;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: var(--bg-base);
  color: var(--text-primary);
  overflow: hidden;
}

/* ─── Header ──────────────────────────────────────────────────────────────── */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  background: var(--bg-surface);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(12px);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 20px;
  gap: 16px;
}

.header-brand {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-shrink: 0;
}


.header-titles h1 {
  font-size: 18px;
  font-weight: 800;
  color: var(--text-primary);
  line-height: 1.2;
  letter-spacing: -0.3px;
}
.header-subtitle {
  font-size: 12px;
  color: var(--text-secondary);
  margin-top: 2px;
}

/* GitHub link */
.github-link {
  display: flex;
  align-items: center;
  gap: 6px;
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 13px;
  font-weight: 500;
  padding: 6px 10px;
  border-radius: 6px;
  border: 1px solid var(--border);
  transition: color 0.15s, border-color 0.15s;
  flex-shrink: 0;
}
.github-link:hover {
  color: var(--text-primary);
  border-color: var(--text-secondary);
}

/* Search */
.search-wrapper {
  position: relative;
  display: flex;
  align-items: center;
}
.search-icon {
  position: absolute;
  left: 10px;
  width: 16px;
  height: 16px;
  color: var(--text-muted);
  pointer-events: none;
}
#search-input {
  width: 240px;
  padding: 7px 32px 7px 34px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: 13px;
  outline: none;
  transition: border-color var(--dur-fast) var(--ease),
              box-shadow var(--dur-fast) var(--ease);
}
#search-input::placeholder { color: var(--text-muted); }
#search-input:focus {
  border-color: var(--accent-blue);
  box-shadow: 0 0 0 3px rgba(88, 166, 255, 0.15);
}
.search-clear {
  position: absolute;
  right: 8px;
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 12px;
  padding: 2px 4px;
  border-radius: 4px;
  display: none;
  line-height: 1;
}
.search-clear:hover { color: var(--text-primary); background: var(--bg-hover); }
.search-clear.visible { display: block; }

/* Filter bar */
.filter-bar {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 20px;
  border-top: 1px solid var(--border-subtle);
  overflow-x: auto;
  scrollbar-width: none;
}
.filter-bar::-webkit-scrollbar { display: none; }

.filter-label {
  font-size: 12px;
  color: var(--text-secondary);
  white-space: nowrap;
  flex-shrink: 0;
}

.filter-chips {
  display: flex;
  gap: 6px;
  flex-shrink: 0;
}

.chip {
  padding: 4px 12px;
  border-radius: 20px;
  border: 1px solid var(--border);
  background: var(--bg-elevated);
  color: var(--text-secondary);
  font-size: 12px;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--dur-fast) var(--ease);
  white-space: nowrap;
}
.chip:hover { border-color: var(--accent-blue); color: var(--accent-blue); }
.chip.active {
  background: var(--accent-blue);
  border-color: var(--accent-blue);
  color: #000;
}
.chip[data-type="guide"].active        { background: var(--color-guide); border-color: var(--color-guide); }
.chip[data-type="standard"].active     { background: var(--color-standard); border-color: var(--color-standard); }
.chip[data-type="cheat sheet"].active  { background: var(--color-cheat-sheet); border-color: var(--color-cheat-sheet); color: #000; }
.chip[data-type="tool"].active         { background: var(--color-tool); border-color: var(--color-tool); }

/* Legend */
.legend {
  display: flex;
  gap: 14px;
  margin-left: auto;
  flex-shrink: 0;
}
.legend-item {
  display: flex;
  align-items: center;
  gap: 5px;
  font-size: 11px;
  color: var(--text-secondary);
  white-space: nowrap;
}
.legend-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  flex-shrink: 0;
}

/* ─── Layout ──────────────────────────────────────────────────────────────── */
.layout {
  display: flex;
  height: 100vh;
  padding-top: var(--header-height);
}

/* ─── Graph Panel ─────────────────────────────────────────────────────────── */
.graph-panel {
  flex: 1;
  position: relative;
  overflow: hidden;
  background: var(--bg-base);
  background-image:
    radial-gradient(circle at 20% 20%, rgba(88,166,255,0.04) 0%, transparent 50%),
    radial-gradient(circle at 80% 80%, rgba(188,140,255,0.04) 0%, transparent 50%);
}

#graph-svg {
  width: 100%;
  height: 100%;
  cursor: grab;
}
#graph-svg:active { cursor: grabbing; }

/* Graph elements */
.link {
  stroke: var(--border);
  stroke-opacity: 0.5;
  fill: none;
  transition: stroke-opacity var(--dur-fast) var(--ease);
}
.link.highlighted {
  stroke: var(--accent-blue);
  stroke-opacity: 0.9;
}
.link.dimmed { stroke-opacity: 0.1; }

.node circle {
  cursor: pointer;
  transition: r var(--dur-fast) var(--ease),
              filter var(--dur-fast) var(--ease),
              opacity var(--dur-fast) var(--ease);
}
.node circle:hover { filter: brightness(1.3); }
.node.dimmed circle { opacity: 0.15; }
.node.dimmed text  { opacity: 0.15; }

.node text {
  font-size: 11px;
  fill: var(--text-secondary);
  pointer-events: none;
  user-select: none;
  transition: fill var(--dur-fast) var(--ease), opacity var(--dur-fast) var(--ease);
}
.node.active text { fill: var(--text-primary); font-weight: 600; }

/* Pulse ring on active node */
.node-pulse {
  animation: pulse 2s var(--ease) infinite;
  pointer-events: none;
}
@keyframes pulse {
  0%   { r: 0; opacity: 0.8; }
  100% { r: 28px; opacity: 0; }
}

.graph-hint {
  position: absolute;
  bottom: 16px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 12px;
  color: var(--text-muted);
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 5px 14px;
  pointer-events: none;
  white-space: nowrap;
}

/* Loading */
.loading {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  color: var(--text-secondary);
  font-size: 14px;
}
.loading.hidden { display: none; }
.loading-spinner {
  width: 32px;
  height: 32px;
  border: 3px solid var(--border);
  border-top-color: var(--accent-blue);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ─── Detail Sidebar ──────────────────────────────────────────────────────── */
.detail-panel {
  width: var(--sidebar-width);
  flex-shrink: 0;
  background: var(--bg-surface);
  border-left: 1px solid var(--border);
  padding: 24px 20px;
  overflow-y: auto;
  transform: translateX(var(--sidebar-width));
  transition: transform var(--dur-slow) var(--ease);
  position: relative;
  scrollbar-width: thin;
  scrollbar-color: var(--border) transparent;
}
.detail-panel.open {
  transform: translateX(0);
}
.detail-panel::-webkit-scrollbar { width: 4px; }
.detail-panel::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }

.detail-close {
  position: absolute;
  top: 16px; right: 16px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  width: 28px; height: 28px;
  cursor: pointer;
  font-size: 14px;
  display: flex; align-items: center; justify-content: center;
  transition: all var(--dur-fast) var(--ease);
}
.detail-close:hover { color: var(--text-primary); background: var(--bg-hover); }

.detail-type-badge {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 20px;
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 10px;
  border: 1px solid currentColor;
}

.detail-title {
  font-size: 18px;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.35;
  margin-bottom: 12px;
}

.detail-description {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.65;
  margin-bottom: 20px;
}

.detail-meta {
  font-size: 12px;
  color: var(--text-muted);
  margin-bottom: 20px;
}
.detail-meta strong { color: var(--text-secondary); }

.detail-link {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 16px;
  background: var(--accent-blue);
  color: #000;
  font-size: 13px;
  font-weight: 600;
  border-radius: var(--radius-md);
  text-decoration: none;
  transition: all var(--dur-fast) var(--ease);
  margin-bottom: 24px;
}
.detail-link svg { width: 16px; height: 16px; flex-shrink: 0; }
.detail-link:hover { background: #79bcff; transform: translateY(-1px); }
.detail-link.hidden { display: none; }

/* Children list */
.detail-children h3 {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.8px;
  margin-bottom: 10px;
  border-top: 1px solid var(--border);
  padding-top: 20px;
}

.child-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 10px 0;
  border-bottom: 1px solid var(--border-subtle);
  cursor: pointer;
  transition: all var(--dur-fast) var(--ease);
  text-decoration: none;
}
.child-item:hover { padding-left: 4px; }
.child-item:hover .child-title { color: var(--accent-blue); }

.child-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  flex-shrink: 0;
  margin-top: 4px;
}

.child-info { flex: 1; min-width: 0; }
.child-title {
  font-size: 13px;
  font-weight: 500;
  color: var(--text-primary);
  transition: color var(--dur-fast) var(--ease);
  margin-bottom: 3px;
  line-height: 1.3;
}
.child-desc {
  font-size: 11px;
  color: var(--text-muted);
  line-height: 1.5;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

/* ─── Tooltip ──────────────────────────────────────────────────────────────── */
.tooltip {
  position: fixed;
  pointer-events: none;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 10px 14px;
  font-size: 12px;
  color: var(--text-primary);
  max-width: 240px;
  line-height: 1.55;
  box-shadow: 0 8px 24px rgba(0,0,0,0.5);
  z-index: 999;
  opacity: 0;
  transform: translateY(4px);
  transition: opacity var(--dur-fast) var(--ease),
              transform var(--dur-fast) var(--ease);
}
.tooltip.visible {
  opacity: 1;
  transform: translateY(0);
}
.tooltip-title {
  font-weight: 700;
  margin-bottom: 4px;
  color: var(--text-primary);
}
.tooltip-type {
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-muted);
  margin-bottom: 5px;
}
.tooltip-desc { color: var(--text-secondary); }

/* ─── Responsive ──────────────────────────────────────────────────────────── */
@media (max-width: 768px) {
  :root { --sidebar-width: 100vw; }

  .detail-panel {
    position: fixed;
    bottom: 0; left: 0; right: 0;
    top: auto;
    width: 100%;
    height: 60vh;
    transform: translateY(100%);
    border-left: none;
    border-top: 1px solid var(--border);
    border-radius: var(--radius-lg) var(--radius-lg) 0 0;
  }
  .detail-panel.open { transform: translateY(0); }

  .header-inner { flex-wrap: wrap; gap: 10px; }
  #search-input { width: 100%; }
  .search-wrapper { width: 100%; }

  .legend { display: none; }

  .layout { flex-direction: column; }
  .graph-panel { flex: 1; }
}

/* ─── Utility ─────────────────────────────────────────────────────────────── */
.sr-only {
  position: absolute; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0,0,0,0); white-space: nowrap; border: 0;
}