:root {
  --bg: #0a0b0e;
  --panel: rgba(18, 20, 26, 0.82);
  --line: rgba(255, 255, 255, 0.08);
  --txt: #e7e9ee;
  --dim: #8b909c;
  --accent: #5eead4;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  height: 100%;
  overflow: hidden;
  background: var(--bg);
  color: var(--txt);
  font-family: ui-sans-serif, -apple-system, "SF Pro Text", "Inter", system-ui, sans-serif;
  -webkit-font-smoothing: antialiased;
}

#sim {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
  cursor: crosshair;
}

#panel {
  position: fixed;
  top: 18px;
  left: 18px;
  width: 268px;
  padding: 18px 18px 14px;
  background: var(--panel);
  backdrop-filter: blur(14px) saturate(140%);
  -webkit-backdrop-filter: blur(14px) saturate(140%);
  border: 1px solid var(--line);
  border-radius: 16px;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.45);
  user-select: none;
}

header h1 {
  margin: 0;
  font-size: 19px;
  font-weight: 650;
  letter-spacing: -0.01em;
}
.sub {
  margin: 2px 0 14px;
  font-size: 12px;
  color: var(--dim);
}

.row.buttons { display: flex; gap: 8px; margin-bottom: 14px; }

button {
  flex: 1;
  padding: 9px 10px;
  font-size: 13px;
  font-weight: 550;
  color: var(--txt);
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--line);
  border-radius: 10px;
  cursor: pointer;
  transition: background 0.15s, transform 0.05s;
}
button:hover { background: rgba(255, 255, 255, 0.12); }
button:active { transform: translateY(1px); }
button.primary { background: rgba(94, 234, 212, 0.14); border-color: rgba(94, 234, 212, 0.35); }

.ctl {
  display: block;
  margin: 0 0 13px;
  font-size: 12.5px;
  color: var(--dim);
}
.ctl > span {
  display: flex;
  justify-content: space-between;
  margin-bottom: 6px;
  color: var(--txt);
}
.ctl i { color: var(--accent); font-style: normal; font-variant-numeric: tabular-nums; }
.ctl small { display: block; margin-top: 4px; font-size: 11px; color: var(--dim); }

input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 4px;
  border-radius: 4px;
  background: rgba(255, 255, 255, 0.12);
  outline: none;
}
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 15px;
  height: 15px;
  border-radius: 50%;
  background: var(--accent);
  cursor: pointer;
  box-shadow: 0 0 0 3px rgba(94, 234, 212, 0.18);
}
input[type="range"]::-moz-range-thumb {
  width: 15px; height: 15px; border: none; border-radius: 50%;
  background: var(--accent); cursor: pointer;
}

select {
  width: 100%;
  padding: 7px 9px;
  font-size: 13px;
  color: var(--txt);
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--line);
  border-radius: 9px;
}

.hint {
  margin: 16px 0 10px;
  font-size: 11.5px;
  line-height: 1.5;
  color: var(--dim);
}

footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 10px;
  border-top: 1px solid var(--line);
  font-size: 11.5px;
}
footer a { color: var(--accent); text-decoration: none; }
footer a:hover { text-decoration: underline; }
#fps { color: var(--dim); font-variant-numeric: tabular-nums; }

@media (max-width: 560px) {
  #panel { width: calc(100% - 24px); left: 12px; top: 12px; }
}