frontend/src/App.css

:root {
  --bg-deep: #000000;
  --bg-surface: #0a0a0a;
  --bg-panel: rgba(10, 10, 10, 0.88);
  --gold: #d4a04a;
  --gold-dim: #a07830;
  --steel: #5b7db5;
  --steel-dim: #3a5075;
  --text: #d0d0da;
  --text-dim: #6b6b78;
  --text-bright: #eeeef4;
  --border: rgba(212, 160, 74, 0.12);
  --border-glow: rgba(212, 160, 74, 0.25);
}

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

html, body, #root {
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: var(--bg-deep);
  font-family: 'Outfit', sans-serif;
  color: var(--text);
}

.app-root {
  width: 100%;
  height: 100%;
  position: relative;
}

.simulation-error {
  position: absolute;
  z-index: 20;
  left: 50%;
  top: 50%;
  width: min(440px, calc(100vw - 40px));
  transform: translate(-50%, -50%);
  padding: 20px 22px;
  border: 1px solid rgba(238, 103, 103, 0.55);
  border-left: 4px solid #ee6767;
  background: rgba(16, 8, 8, 0.94);
  box-shadow: 0 18px 55px rgba(0, 0, 0, 0.55);
  color: var(--text-bright);
  animation: fadeIn 180ms ease-out;
}

.simulation-error__eyebrow {
  display: block;
  margin-bottom: 8px;
  color: #ff8b8b;
  font-family: 'Outfit', sans-serif;
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.15em;
  text-transform: uppercase;
}

.simulation-error p {
  line-height: 1.45;
}

.simulation-error small {
  display: block;
  margin-top: 12px;
  color: var(--text-dim);
  line-height: 1.4;
}

canvas {
  display: block;
}

::-webkit-scrollbar {
  width: 4px;
}
::-webkit-scrollbar-track {
  background: transparent;
}
::-webkit-scrollbar-thumb {
  background: rgba(212, 160, 74, 0.2);
  border-radius: 2px;
}

::selection {
  background: rgba(212, 160, 74, 0.3);
  color: var(--text-bright);
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(4px); }
  to   { opacity: 1; transform: translateY(0); }
}