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

:root {
  --bg-deep: #050a14;
  --bg-mid: #0a1628;
  --bg-card: rgba(10, 18, 36, 0.88);
  --border: rgba(255, 255, 255, 0.07);
  --border-hover: rgba(255, 255, 255, 0.18);
  --text: #cbd5e1;
  --text-dim: #64748b;
  --text-bright: #f1f5f9;
  --panel-w: 380px;
  --accent: #00d4ff;
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  background: linear-gradient(170deg, var(--bg-deep) 0%, var(--bg-mid) 50%, #0d1220 100%);
  color: var(--text);
  min-height: 100vh;
  overflow-x: hidden;
}

/* === Starfield === */
#stars {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
}

/* === Page layout === */
.page {
  position: relative;
  z-index: 1;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 1.75rem 2rem 1rem;
}

/* === Header === */
.header {
  text-align: center;
  margin-bottom: 2rem;
}

.brand {
  font-size: 0.7rem;
  letter-spacing: 0.35em;
  color: var(--text-dim);
  margin-bottom: 0.25rem;
}

.header h1 {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--text-bright);
  letter-spacing: -0.01em;
}

.tagline {
  font-size: 0.85rem;
  color: var(--text-dim);
  margin-top: 0.35rem;
}

/* === Diagram === */
.diagram {
  position: relative;
  width: 100%;
  max-width: 1060px;
  aspect-ratio: 16 / 9;
  flex-shrink: 0;
}

/* === SVG connection lines === */
.lines {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: 3;
  pointer-events: none;
  overflow: visible;
}

.conn-line {
  fill: none;
  stroke: rgba(255, 255, 255, 0.13);
  stroke-width: 1.5;
  transition: stroke 0.3s ease, stroke-width 0.3s ease;
}

.conn-line.dashed {
  stroke: rgba(255, 255, 255, 0.06);
  stroke-dasharray: 5 5;
  stroke-width: 1;
}

.conn-hit {
  fill: none;
  stroke: transparent;
  stroke-width: 24;
  cursor: pointer;
  pointer-events: stroke;
}

.conn-line.hl {
  stroke: rgba(255, 255, 255, 0.5);
  stroke-width: 2.5;
}

.conn-line.dashed.hl {
  stroke: rgba(255, 255, 255, 0.35);
  stroke-width: 1.5;
}

.conn-label {
  font-size: 10px;
  font-weight: 500;
  fill: var(--text-dim);
  text-anchor: middle;
  dominant-baseline: central;
  pointer-events: none;
  transition: fill 0.3s ease;
  stroke: var(--bg-deep);
  stroke-width: 3px;
  paint-order: stroke;
}

.conn-label.dashed-lbl {
  fill: rgba(100, 116, 139, 0.45);
}

.conn-label.hl {
  fill: var(--text-bright);
}

/* === Node cards === */
.nodes {
  position: absolute;
  inset: 0;
  z-index: 2;
}

.node {
  position: absolute;
  transform: translate(-50%, -50%);
  width: 176px;
  background: var(--bg-card);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 1rem 1.1rem;
  cursor: pointer;
  transition: transform 0.25s ease, border-color 0.3s ease, box-shadow 0.3s ease;
  user-select: none;
  text-align: left;
  font-family: inherit;
  color: inherit;
  outline: none;
}

.node:hover {
  transform: translate(-50%, -50%) scale(1.04);
  border-color: var(--border-hover);
}

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

.node.active {
  border-color: var(--node-color, var(--accent));
  box-shadow: 0 0 28px -6px var(--node-color, var(--accent));
}

/* Accent bar */
.node::before {
  content: '';
  position: absolute;
  left: 0;
  top: 14px;
  bottom: 14px;
  width: 3px;
  border-radius: 0 3px 3px 0;
  background: var(--node-color, var(--accent));
  opacity: 0.5;
  transition: opacity 0.3s ease;
}

.node:hover::before,
.node.active::before {
  opacity: 1;
}

.node-icon {
  font-size: 1.15rem;
  margin-bottom: 0.3rem;
}

.node-title {
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--text-bright);
  margin-bottom: 0.12rem;
}

.node-tagline {
  font-size: 0.68rem;
  color: var(--text-dim);
  line-height: 1.3;
  margin-bottom: 0.45rem;
}

.node-items {
  list-style: none;
  padding: 0;
}

.node-items li {
  font-size: 0.62rem;
  color: var(--text-dim);
  padding: 0.1rem 0 0.1rem 0.75rem;
  position: relative;
  line-height: 1.35;
}

.node-items li::before {
  content: '\203A';
  position: absolute;
  left: 0;
  color: var(--node-color, var(--accent));
  font-weight: 700;
}

.node-note {
  font-size: 0.58rem;
  color: var(--node-color, var(--accent));
  opacity: 0.65;
  margin-top: 0.35rem;
  padding-top: 0.3rem;
  border-top: 1px solid var(--border);
}

/* === Hub (center node) === */
.node.hub {
  width: 210px;
  padding: 1.25rem 1.3rem;
  border-width: 1.5px;
  border-color: rgba(0, 212, 255, 0.2);
  box-shadow: 0 0 40px -10px rgba(0, 212, 255, 0.12);
  animation: hubGlow 5s ease-in-out infinite;
}

.node.hub .node-title { font-size: 1rem; }
.node.hub .node-tagline { font-size: 0.78rem; margin-bottom: 0; }

@keyframes hubGlow {
  0%, 100% { box-shadow: 0 0 40px -10px rgba(0, 212, 255, 0.12); }
  50%      { box-shadow: 0 0 50px -6px rgba(0, 212, 255, 0.22); }
}

/* === Detail panel === */
.panel {
  position: fixed;
  top: 0;
  right: 0;
  width: var(--panel-w);
  height: 100vh;
  background: rgba(8, 14, 30, 0.94);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border-left: 1px solid var(--border);
  z-index: 100;
  padding: 2.5rem 1.75rem 2rem;
  overflow-y: auto;
  transform: translateX(100%);
  visibility: hidden;
  transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1),
              visibility 0s 0.35s;
}

.panel.open {
  transform: translateX(0);
  visibility: visible;
  transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1),
              visibility 0s;
}

.panel-close {
  position: absolute;
  top: 1rem;
  right: 1rem;
  background: none;
  border: 1px solid var(--border);
  color: var(--text-dim);
  width: 32px;
  height: 32px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 1rem;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: border-color 0.2s, color 0.2s;
}

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

.panel-cat {
  font-size: 0.65rem;
  letter-spacing: 0.25em;
  text-transform: uppercase;
  margin-bottom: 0.5rem;
}

.panel-heading {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text-bright);
  margin-bottom: 1rem;
  line-height: 1.25;
}

.panel-desc {
  font-size: 0.88rem;
  line-height: 1.65;
  color: var(--text);
  margin-bottom: 1.5rem;
}

.panel-section {
  font-size: 0.65rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--text-dim);
  margin-bottom: 0.6rem;
}

.panel-list {
  list-style: none;
  padding: 0;
  margin-bottom: 1.5rem;
}

.panel-list li {
  font-size: 0.82rem;
  line-height: 1.55;
  color: var(--text);
  padding: 0.35rem 0 0.35rem 1.1rem;
  position: relative;
}

.panel-list li::before {
  content: '\2192';
  position: absolute;
  left: 0;
  color: var(--node-color, var(--accent));
}

/* === Footer === */
.footer {
  margin-top: auto;
  padding-top: 1.25rem;
  font-size: 0.72rem;
  color: var(--text-dim);
  text-align: center;
}

.dot {
  margin: 0 0.5rem;
  opacity: 0.5;
}

/* === Responsive === */
@media (max-width: 900px) {
  .diagram { max-width: 100%; }
  .node { width: 148px; padding: 0.75rem 0.85rem; }
  .node.hub { width: 172px; }
  .node-title { font-size: 0.82rem; }
  .node-tagline { font-size: 0.62rem; }
  .node-items li { font-size: 0.58rem; }
}

@media (max-width: 700px) {
  .page { padding: 1rem 0.75rem; }
  .header { margin-bottom: 1rem; }
  .header h1 { font-size: 1.3rem; }

  /* Switch diagram from absolute positioning to flow layout */
  .diagram {
    aspect-ratio: auto;
    max-width: 100%;
  }

  /* Hide SVG connection lines on mobile */
  .lines { display: none; }

  /* Make node list a 2-column grid */
  .nodes {
    position: relative;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.6rem;
    padding: 0.25rem;
  }

  .node {
    position: static;
    transform: none;
    width: auto;
    padding: 0.75rem 0.85rem;
  }

  .node:hover {
    transform: scale(1.02);
  }

  .node.hub {
    grid-column: 1 / -1;
    width: auto;
    padding: 0.85rem 1rem;
  }

  .node-items { display: none; }
  .node-note { display: none; }

  /* Panel slides up from bottom on mobile */
  .panel {
    width: 100%;
    height: 65vh;
    top: auto;
    bottom: 0;
    border-left: none;
    border-top: 1px solid var(--border);
    border-radius: 16px 16px 0 0;
    transform: translateY(100%);
  }
  .panel.open { transform: translateY(0); }

  .footer { margin-top: 1.5rem; }
}