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

:root {
  --bg: #0f1117;
  --surface: #1a1d27;
  --border: #2e3347;
  --text: #e8eaf0;
  --muted: #8890a8;
  --accent: #e8a020;

  --cat-executive-function: #4e9af1;
  --cat-emotional-regulation: #e86040;
  --cat-sensory: #a06de8;
  --cat-social: #40c878;
  --cat-parenting-strategy: #e8c040;
  --cat-neuroscience: #40c8e8;
  --cat-other: #8890a8;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, sans-serif;
  height: 100dvh;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

/* Header */
header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 0.75rem 1.25rem;
  flex-shrink: 0;
}

.header-inner {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
}

h1 {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--accent);
  white-space: nowrap;
}

.subtitle {
  font-size: 0.85rem;
  color: var(--muted);
  white-space: nowrap;
}

/* Legend */
.legend {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1rem;
  margin-left: auto;
}

.legend-item {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.75rem;
  color: var(--muted);
}

.legend-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  flex-shrink: 0;
}

/* Graph */
.graph-wrap {
  flex: 1;
  position: relative;
  overflow: hidden;
}

#graph {
  width: 100%;
  height: 100%;
  display: block;
}

.link {
  stroke: var(--border);
  stroke-opacity: 0.6;
}

.node circle {
  stroke: var(--bg);
  stroke-width: 2;
  cursor: pointer;
  transition: filter 0.15s;
}

.node circle:hover,
.node.hovered circle {
  filter: brightness(1.4);
}

.node text {
  font-size: 11px;
  fill: var(--text);
  pointer-events: none;
  user-select: none;
}

/* Tooltip */
.tooltip {
  position: absolute;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.75rem 1rem;
  max-width: 280px;
  font-size: 0.82rem;
  line-height: 1.5;
  pointer-events: none;
  box-shadow: 0 4px 20px rgba(0,0,0,0.5);
  z-index: 100;
}

.tooltip[hidden] { display: none; }

.tooltip-title {
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--text);
  margin-bottom: 0.3rem;
}

.tooltip-desc {
  color: var(--muted);
  margin-bottom: 0.4rem;
}

.tooltip-episodes {
  font-size: 0.75rem;
  color: var(--accent);
}

/* Side panel */
.panel {
  position: fixed;
  top: 0;
  right: 0;
  width: min(380px, 100vw);
  height: 100%;
  background: var(--surface);
  border-left: 1px solid var(--border);
  padding: 1.5rem;
  overflow-y: auto;
  z-index: 200;
  transform: translateX(100%);
  transition: transform 0.25s ease;
}

.panel:not([hidden]) {
  transform: translateX(0);
}

.panel[hidden] { display: block !important; } /* override hidden so transitions work */

.panel-close {
  position: absolute;
  top: 1rem;
  right: 1rem;
  background: none;
  border: 1px solid var(--border);
  color: var(--muted);
  border-radius: 4px;
  width: 28px;
  height: 28px;
  cursor: pointer;
  font-size: 0.85rem;
  display: flex;
  align-items: center;
  justify-content: center;
}

.panel-close:hover { color: var(--text); border-color: var(--text); }

#panel-content h2 {
  font-size: 1.15rem;
  color: var(--accent);
  margin-bottom: 0.75rem;
  padding-right: 2rem;
}

#panel-content p {
  font-size: 0.87rem;
  color: var(--muted);
  line-height: 1.6;
  margin-bottom: 1rem;
}

#panel-content h3 {
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted);
  margin-bottom: 0.5rem;
}

.panel-ep-list {
  list-style: none;
  margin-bottom: 1rem;
}

.panel-ep-list li {
  font-size: 0.83rem;
  color: var(--text);
  padding: 0.35rem 0;
  border-bottom: 1px solid var(--border);
  line-height: 1.5;
}

.panel-ep-num {
  color: var(--accent);
  font-weight: 600;
  margin-right: 0.4rem;
}

.panel-related {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-bottom: 1rem;
}

.panel-related-tag {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 0.2rem 0.5rem;
  font-size: 0.75rem;
  color: var(--muted);
  cursor: pointer;
  transition: border-color 0.15s, color 0.15s;
}

.panel-related-tag:hover {
  border-color: var(--accent);
  color: var(--text);
}

/* Loading overlay */
.loading-overlay {
  position: fixed;
  inset: 0;
  background: var(--bg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  color: var(--muted);
  z-index: 999;
  transition: opacity 0.4s;
}

.loading-overlay.done {
  opacity: 0;
  pointer-events: none;
}