:root {
  --bg: #0e1116;
  --panel: #151a21;
  --panel-2: #1b2129;
  --border: #242b35;
  --fg: #d8dde4;
  --fg-muted: #8a94a3;
  --accent: #ffbf47;
  --accent-soft: #7cc7ff;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; height: 100%; background: var(--bg); color: var(--fg); font-family: -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif; }
body { display: grid; grid-template-columns: 425px 1fr; height: 100vh; overflow: hidden; }

#sidebar {
  background: var(--panel);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  min-height: 0;
}
#brand {
  display: block;
  padding: 18px 22px;
  background: #ffffff;
  border-bottom: 1px solid var(--border);
  transition: background .12s ease;
}
#brand:hover { background: #f3f6fa; }
#brand img {
  display: block;
  width: 100%;
  height: auto;
}
#sidebar header { padding: 22px 22px 13px; border-bottom: 1px solid var(--border); }
#sidebar header h1 { margin: 0; font-size: 25px; letter-spacing: 0.02em; }
#sidebar header .sub { margin: 5px 0 0; color: var(--fg-muted); font-size: 15px; }

#cat-list { flex: 1; overflow-y: auto; padding: 10px 0; }
#cat-list .loading { padding: 20px 22px; color: var(--fg-muted); font-style: italic; font-size: 16px; }

.category { border-bottom: 1px solid var(--border); }
.category > .cat-header {
  width: 100%;
  background: transparent;
  color: var(--fg);
  border: 0;
  padding: 12px 22px;
  text-align: left;
  font-size: 15px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.category > .cat-header:hover { background: var(--panel-2); }
.category > .cat-header .chev { transition: transform .15s ease; color: var(--fg-muted); }
.category.collapsed > .cat-header .chev { transform: rotate(-90deg); }
.category.collapsed .parts { display: none; }

.parts { list-style: none; margin: 0; padding: 0 0 8px; }
.part {
  padding: 10px 22px 10px 32px;
  cursor: pointer;
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 3px 12px;
  font-size: 16px;
  line-height: 1.35;
  border-left: 3px solid transparent;
  transition: background .1s ease, border-color .1s ease;
}
.part:hover { background: var(--panel-2); }
.part.active {
  background: var(--panel-2);
  border-left-color: var(--accent);
}
.part .mpn { font-weight: 600; font-family: ui-monospace, "Cascadia Mono", Consolas, monospace; color: var(--fg); }
.part .count { color: var(--accent); font-variant-numeric: tabular-nums; font-size: 15px; }
.part .desc { grid-column: 1 / -1; color: var(--fg-muted); font-size: 14px; margin-top: 3px; }

#sidebar footer { padding: 15px 22px; border-top: 1px solid var(--border); background: var(--panel-2); }
#sidebar footer .hint { margin: 0; font-size: 14px; color: var(--fg-muted); }
#reset-btn {
  display: block;
  width: 100%;
  margin-bottom: 12px;
  padding: 10px;
  background: var(--panel);
  color: var(--fg);
  border: 1px solid var(--border);
  border-radius: 4px;
  font-size: 15px;
  cursor: pointer;
}
#reset-btn:hover { border-color: var(--accent); color: var(--accent); }

#stage { position: relative; min-width: 0; min-height: 0; background: radial-gradient(ellipse at center, #1a2029 0%, #0b0d11 100%); }
#view { display: block; width: 100%; height: 100%; cursor: grab; touch-action: none; }
#view:active { cursor: grabbing; }

#loading-overlay {
  position: absolute; inset: 0;
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  background: rgba(11, 13, 17, 0.85);
  color: var(--fg-muted);
  font-size: 16px;
  gap: 18px;
  pointer-events: none;
  transition: opacity .3s ease;
}
#loading-overlay.hidden { opacity: 0; pointer-events: none; }
.spinner {
  width: 40px; height: 40px;
  border: 4px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

#selection-info {
  position: absolute; left: 20px; bottom: 20px;
  background: rgba(21, 26, 33, 0.92);
  backdrop-filter: blur(6px);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: 4px;
  padding: 15px 20px;
  max-width: 450px;
  font-size: 16px;
  line-height: 1.4;
}
#selection-info .sel-head {
  display: flex;
  align-items: center;
  gap: 10px;
}
#selection-info strong { font-family: ui-monospace, "Cascadia Mono", Consolas, monospace; font-size: 19px; }
#selection-info #sel-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--accent-soft);
  text-decoration: none;
  border-radius: 3px;
  padding: 2px;
  transition: color .12s ease, background .12s ease;
}
#selection-info #sel-link:hover {
  color: var(--accent);
  background: rgba(255, 191, 71, 0.12);
}
#selection-info #sel-link[hidden] { display: none; }
#selection-info #sel-desc { margin: 10px 0 0; color: var(--fg); }

@media (max-width: 760px) {
  body { grid-template-columns: 1fr; grid-template-rows: 1fr auto; }
  #sidebar { max-height: 45vh; border-right: 0; border-top: 1px solid var(--border); order: 2; }
}