:root {
  --card-bg: rgba(255,255,255,0.82);
}
body {
  background: radial-gradient(circle at top left, #dbeafe 0%, #eef2ff 30%, #f8fafc 60%, #ffffff 100%);
  min-height: 100vh;
}
.glass, .card {
  background: var(--card-bg);
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255,255,255,0.45);
  box-shadow: 0 12px 32px rgba(15,23,42,0.08);
}
.hero {
  background: linear-gradient(135deg, #0f172a, #1d4ed8 45%, #06b6d4);
  color: white;
  border-radius: 1.5rem;
  padding: 2rem;
  box-shadow: 0 20px 50px rgba(29,78,216,.25);
}
.binary-box {
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: .96rem;
  background: #0f172a;
  color: #e2e8f0;
  border-radius: 1rem;
  padding: 1rem;
  overflow-x: auto;
}
.bit-net { color: #38bdf8; }
.bit-host { color: #cbd5e1; }
.mask-cut {
  display: inline-block;
  width: 3px;
  height: 1.2em;
  background: #ef4444;
  margin: 0 .25rem;
  vertical-align: middle;
  border-radius: 999px;
}
.range-bar {
  position: relative;
  height: 76px;
  padding-top: 26px;
}
.range-line {
  position: absolute;
  top: 50px;
  left: 0;
  right: 0;
  height: 8px;
  border-radius: 999px;
  background: linear-gradient(90deg,#10b981,#f59e0b,#ef4444);
}
.range-marker {
  position: absolute;
  top: 6px;
  transform: translateX(-50%);
  text-align: center;
  min-width: 140px;
}
.range-marker .arrow {
  font-size: 1.8rem;
  line-height: 1;
  color: #111827;
}
.split-node {
  border-left: 3px solid #cbd5e1;
  margin-left: 1rem;
  padding-left: 1rem;
}
.split-label.strike {
  text-decoration: line-through;
  opacity: .55;
}
.network-badge {
  font-family: ui-monospace, monospace;
  font-size: .95rem;
}
.tree-box {
  max-height: 68vh;
  overflow: auto;
}
.visual-row { border-left: 5px solid #60a5fa; }
.small-help { font-size: .88rem; color: #475569; }