:root {
  color-scheme: dark;
  --bg: #08111f;
  --panel: #101b2e;
  --panel-2: #15233a;
  --line: #2b3d59;
  --text: #edf4ff;
  --muted: #9fb0c8;
  --accent: #55c8ff;
  --accent-2: #7cf1c8;
  --warning: #ffca6a;
  --danger: #ff7c8e;
  --track: #dce9f7;
  --shadow: rgba(0, 0, 0, 0.35);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(circle at 15% 0%, rgba(85, 200, 255, 0.13), transparent 32rem),
    linear-gradient(180deg, #07101d, var(--bg));
  color: var(--text);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

button, input { font: inherit; }

.app {
  width: min(1440px, 100%);
  margin: 0 auto;
  padding: 20px;
}

.topbar {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 20px;
  margin-bottom: 16px;
}

h1 {
  margin: 0 0 5px;
  font-size: clamp(1.35rem, 2.7vw, 2rem);
  font-weight: 680;
  letter-spacing: -0.025em;
}

.subtitle {
  margin: 0;
  color: var(--muted);
  line-height: 1.5;
}

.challenge-chip {
  flex: 0 0 auto;
  border: 1px solid rgba(85, 200, 255, 0.36);
  border-radius: 999px;
  padding: 9px 13px;
  background: rgba(85, 200, 255, 0.08);
  color: #cfefff;
  font-size: 0.9rem;
  white-space: nowrap;
}

.layout {
  display: grid;
  grid-template-columns: minmax(260px, 330px) minmax(0, 1fr);
  gap: 16px;
  align-items: start;
}

.panel {
  background: linear-gradient(180deg, rgba(21, 35, 58, 0.96), rgba(13, 24, 42, 0.96));
  border: 1px solid var(--line);
  border-radius: 18px;
  box-shadow: 0 18px 45px var(--shadow);
}

.controls { padding: 17px; }

.section-title {
  margin: 0 0 13px;
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 750;
  letter-spacing: 0.11em;
  text-transform: uppercase;
}

.control { margin-bottom: 19px; }

.control-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 10px;
  margin-bottom: 8px;
}

.control label {
  color: var(--text);
  font-size: 0.96rem;
  font-weight: 600;
}

.value {
  color: var(--accent);
  font-variant-numeric: tabular-nums;
  font-weight: 720;
}

input[type="range"] {
  width: 100%;
  accent-color: var(--accent);
  cursor: pointer;
}

.range-scale {
  display: flex;
  justify-content: space-between;
  margin-top: 4px;
  color: var(--muted);
  font-size: 0.73rem;
}

.button-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 9px;
  margin: 4px 0 18px;
}

button {
  min-height: 42px;
  border: 1px solid var(--line);
  border-radius: 11px;
  background: #17263e;
  color: var(--text);
  padding: 9px 11px;
  cursor: pointer;
  transition: transform 120ms ease, border-color 120ms ease, background 120ms ease;
}

button:hover { border-color: #4b668c; background: #1b2d49; }
button:active { transform: translateY(1px); }
button:focus-visible { outline: 3px solid rgba(85, 200, 255, 0.4); outline-offset: 2px; }

.primary {
  border-color: rgba(85, 200, 255, 0.62);
  background: var(--accent);
  color: #03131e;
  font-weight: 760;
}

.primary:hover { background: #7ad5ff; border-color: #9de2ff; }
.wide { grid-column: 1 / -1; }

.checks {
  display: grid;
  gap: 10px;
  margin-bottom: 17px;
}

.check-row {
  display: flex;
  align-items: center;
  gap: 9px;
  color: var(--muted);
  font-size: 0.91rem;
  cursor: pointer;
}

.check-row input { accent-color: var(--accent); }

.prediction {
  padding: 13px;
  border: 1px solid var(--line);
  border-radius: 13px;
  background: rgba(4, 12, 23, 0.42);
}

.prediction strong { display: block; margin-bottom: 5px; }
.prediction p { margin: 0; color: var(--muted); font-size: 0.88rem; line-height: 1.45; }
.stage { overflow: hidden; }

.hud {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border-bottom: 1px solid var(--line);
}

.metric {
  min-width: 0;
  padding: 12px 13px;
  background: var(--panel);
}

.metric span {
  display: block;
  margin-bottom: 3px;
  color: var(--muted);
  font-size: 0.72rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.metric strong {
  display: block;
  overflow: hidden;
  color: var(--text);
  font-size: clamp(0.9rem, 1.5vw, 1.08rem);
  font-variant-numeric: tabular-nums;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.canvas-wrap {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 9;
  min-height: 360px;
  background: #07111f;
}

canvas {
  display: block;
  width: 100%;
  height: 100%;
  touch-action: none;
}

.canvas-message {
  position: absolute;
  left: 50%;
  top: 17px;
  transform: translateX(-50%);
  max-width: calc(100% - 30px);
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: 999px;
  padding: 7px 12px;
  background: rgba(6, 16, 30, 0.78);
  backdrop-filter: blur(6px);
  color: var(--text);
  font-size: 0.86rem;
  text-align: center;
  pointer-events: none;
}

.energy {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 10px;
  padding: 13px;
  border-top: 1px solid var(--line);
  background: var(--panel);
}

.energy-item span {
  display: flex;
  justify-content: space-between;
  gap: 8px;
  margin-bottom: 6px;
  color: var(--muted);
  font-size: 0.78rem;
}

.bar {
  height: 8px;
  overflow: hidden;
  border-radius: 999px;
  background: #263751;
}

.bar > i {
  display: block;
  width: 0;
  height: 100%;
  border-radius: inherit;
  transition: width 70ms linear;
}

.kinetic i { background: var(--accent); }
.potential i { background: var(--warning); }
.total i { background: var(--accent-2); }

details {
  margin-top: 16px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: rgba(13, 24, 42, 0.72);
  padding: 12px 14px;
}

summary { cursor: pointer; font-weight: 650; }

details p {
  margin: 10px 0 0;
  color: var(--muted);
  line-height: 1.55;
}

code {
  color: #d7f5ff;
  font-family: "SFMono-Regular", Consolas, monospace;
}

.footer-note {
  margin: 12px 2px 0;
  color: var(--muted);
  font-size: 0.78rem;
  line-height: 1.45;
}

.sr-only {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  padding: 0 !important;
  margin: -1px !important;
  overflow: hidden !important;
  clip: rect(0, 0, 0, 0) !important;
  white-space: nowrap !important;
  border: 0 !important;
}

.diagnostics {
  margin-top: 10px;
  color: var(--muted);
  font-size: 0.76rem;
}

.diagnostics summary { font-size: 0.78rem; }

@media (max-width: 900px) {
  .layout { grid-template-columns: 1fr; }
  .controls { order: 2; }
  .stage { order: 1; }
  .hud { grid-template-columns: repeat(3, 1fr); }
  .hud .metric:nth-child(4), .hud .metric:nth-child(5) { grid-column: span 1; }
}

@media (max-width: 600px) {
  .app { padding: 10px; }
  .topbar { display: block; }
  .challenge-chip { display: inline-block; margin-top: 10px; }
  .hud { grid-template-columns: repeat(2, 1fr); }
  .metric:last-child { grid-column: 1 / -1; }
  .canvas-wrap { min-height: 310px; aspect-ratio: 4 / 3; }
  .energy { grid-template-columns: 1fr; }
}