:root {
  --bg: #0f1220;
  --panel: #161a2b;
  --text: #e5e7ef;
  --muted: #97a0b5;
  --accent: #6bc2ff;
  --accent-2: #58f0a7;
  --danger: #ff6b6b;
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: Inter, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji";
  background: linear-gradient(180deg, #0f1220 0%, #0b0e1a 100%);
  color: var(--text);
}
header {
  padding: 16px 24px;
  border-bottom: 1px solid #232842;
}
h1 { margin: 0; font-size: 22px; }
.subtitle { margin: 4px 0 0; color: var(--muted); }

.layout {
  display: grid;
  grid-template-columns: 1fr;
  grid-template-areas:
    "controls"
    "sim"
    "chart";
  gap: 16px;
  padding: 16px;
}
.controls { grid-area: controls; }
.sim { grid-area: sim; }
.chart { grid-area: chart; }
.panel {
  background: var(--panel);
  border: 1px solid #242a47;
  border-radius: 10px;
  padding: 16px;
}
.panel h2 { margin: 0 0 8px; font-size: 18px; }


.controls h3 { margin: 16px 0 8px; font-size: 14px; color: var(--muted); }
.controls .controls-row { display: flex; align-items: center; gap: 8px; }
.controls .inline { display: flex; align-items: center; gap: 8px; margin-left: auto; }
.controls input[type="number"],
.controls input[type="range"] {
  width: 100%;
  padding: 6px 8px;
  border-radius: 6px;
  border: 1px solid #2b3256;
  background: #0f1330;
  color: var(--text);
}
.controls select {
  width: 100%;
  padding: 6px 8px;
  border-radius: 6px;
  border: 1px solid #2b3256;
  background: #0f1330;
  color: var(--text);
}
.grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px 12px;
}
label { display: grid; gap: 6px; font-size: 12px; color: var(--muted); }

button {
  background: var(--accent);
  color: #0b0e1a;
  border: none;
  padding: 8px 12px;
  border-radius: 8px;
  font-weight: 600;
  cursor: pointer;
}
button.secondary { background: #2b3256; color: var(--text); }
button:disabled { opacity: 0.6; cursor: not-allowed; }

.stats { display: flex; gap: 16px; margin-top: 12px; color: var(--muted); }

.panel.sim { max-height: 48vh; overflow: hidden; }
.sim canvas { width: 100%; height: auto; max-height: 46vh; image-rendering: pixelated; border-radius: 8px; border: 1px solid #2b3256; }
.panel.chart { height: 280px; overflow: hidden; display: flex; flex-direction: column; }
.panel.chart h2 { margin-bottom: 0; }
#chartCanvasContainer { flex: 1 1 auto; min-height: 200px; }
.chart canvas { width: 100%; height: 100%; border-radius: 8px; border: 1px solid #2b3256; background: #0b0e1a; }

/* Panel header with action button */
.panel .panel-header { display: flex; align-items: center; justify-content: space-between; margin-bottom: 8px; }
.panel .panel-header h2 { margin: 0; }
.panel .chart-actions { display: flex; align-items: center; gap: 8px; }
label.small { font-size: 11px; color: var(--muted); }

/* Chart modal */
.modal { position: fixed; inset: 0; display: grid; place-items: center; z-index: 1000; }
.modal[hidden] { display: none; }
.modal-backdrop { position: absolute; inset: 0; background: rgba(0,0,0,0.55); backdrop-filter: blur(2px); }
.modal-content { position: relative; width: 96vw; height: 90vh; background: var(--panel); border: 1px solid #242a47; border-radius: 10px; display: grid; grid-template-rows: auto 1fr; overflow: hidden; max-width: 1200px; }
.modal-bar { display: flex; align-items: center; justify-content: space-between; padding: 8px 10px; border-bottom: 1px solid #2b3256; color: var(--muted); }
.modal-actions { display: flex; align-items: center; gap: 8px; }
.modal-canvas-host { width: 100%; height: 100%; padding: 10px; }
.modal-canvas-host canvas { width: 100% !important; height: 100% !important; }

/* Prevent background scroll when modal open */
body.no-scroll { overflow: hidden; }

/* Touch targets */
button, label.small { touch-action: manipulation; }
button { min-height: 36px; }
input[type="checkbox"] { width: 18px; height: 18px; }

@media (max-width: 600px) {
  .panel .panel-header { flex-direction: column; align-items: flex-start; gap: 8px; }
  .panel .chart-actions { width: 100%; justify-content: space-between; }
  .modal-content { width: 98vw; height: 92vh; }
  .modal-bar { flex-wrap: wrap; gap: 6px; }
}

/* Slightly shorter on narrow screens */
@media (max-width: 1100px) {
  .panel.chart { height: auto; min-height: 320px; }
}

.warning {
  background: rgba(255, 107, 107, 0.12);
  color: #ffb3b3;
  border: 1px solid rgba(255, 107, 107, 0.35);
  padding: 8px 10px;
  border-radius: 8px;
  font-size: 12px;
  margin-bottom: 8px;
}

footer {
  padding: 8px 16px 16px;
  color: var(--muted);
}
footer a { color: var(--accent-2); text-decoration: none; }

/* Advanced dropdown */
details.advanced > summary {
  cursor: pointer;
  margin: 10px 0;
  color: var(--muted);
}
details.advanced[open] > summary { color: var(--text); }
details.advanced .grid-2 { margin-top: 6px; }

@media (min-width: 1100px) {
  .layout {
    grid-template-columns: 1fr 1fr;
    grid-template-areas:
      "controls controls"
      "sim chart";
  }
  /* Make controls feel horizontal by widening input grids */
  .controls .grid-2 { grid-template-columns: repeat(4, 1fr); }
  .controls .controls-row { flex-wrap: wrap; }
  .controls h3 { margin-top: 8px; }
  .controls .stats { margin-top: 8px; }

  /* Side-by-side panels at a balanced height */
  .panel.sim { max-height: 48vh; }
  .panel.chart { height: 48vh; }
}

/* Small screens: make chart tall enough for axis visibility */
@media (max-width: 600px) {
  .panel.chart { min-height: 50vh; height: auto; }
  #chartCanvasContainer { min-height: 280px; }
}