:root {
  --bg: #0f1115;
  --fg: #e6e6e6;
  --panel-bg: #151923;
  --panel-border: #2a3347;
  --accent: #4ea1ff;
  /* Controls & grid (dark) */
  --control-surface: #1c2230;
  --control-border: #2a3347;
  --control-text: var(--fg);
  --pill-bg: #1c2230;
  --grid-stroke: rgba(255,255,255,0.12);
  --accent-contrast: #09111f;
  --alive-fill: #4ea1ff;
}

html[data-theme="light"] {
  --bg: #ffffff;
  --fg: #111111;
  --panel-bg: #f3f5f7;
  --panel-border: #cfd6de;
  --accent: #0b6dff;
  /* Controls & grid (light) */
  --control-surface: #ffffff;
  --control-border: #cfd6de;
  --control-text: var(--fg);
  --pill-bg: #eef2f6;
  --grid-stroke: rgba(0,0,0,0.18);
  --accent-contrast: #ffffff;
  --alive-fill: #2b7cff;
}

* { box-sizing: border-box; }
html, body, #app { height: 100%; margin: 0; }
body { background: var(--bg); color: var(--fg); font-family: system-ui, -apple-system, Segoe UI, Roboto, Ubuntu, Cantarell, "Noto Sans", "Helvetica Neue", Arial, "Apple Color Emoji", "Segoe UI Emoji"; }

#app { display: grid; grid-template-columns: 280px 1fr minmax(300px, 360px); grid-template-rows: auto 1fr; min-height: 100vh; gap: 12px; }
.app-header { grid-column: 1 / span 3; padding: 12px; }
.app-header h1 { margin: 0 0 4px; font-size: 18px; }
.app-header .subtitle { margin: 0; opacity: 0.8; font-size: 13px; }
#controls { background: var(--panel-bg); padding: 12px; overflow: auto; grid-column: 1; }
#ca-canvas { width: 100%; height: 100%; display: block; background: var(--bg); grid-column: 2; }
#analytics { background: var(--panel-bg); padding: 12px; overflow: auto; grid-column: 3; }

@media (max-width: 1100px) {
  #app { grid-template-columns: 1fr; grid-template-rows: auto auto auto 1fr; }
  .app-header { grid-column: 1; }
  #controls { grid-column: 1; }
  #ca-canvas { grid-column: 1; }
  #analytics { grid-column: 1; }
}

/* Controls base styles */
#controls {
  display: grid;
  gap: 12px;
}

.group {
  background: var(--panel-bg);
  padding: 10px;
  border-radius: 8px;
  border: 1px solid var(--panel-border);
}

.group h3 {
  margin: 0 0 8px;
  font-size: 14px;
  font-weight: 600;
  opacity: 0.9;
}

.row { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }

button, select, input[type="text"], input[type="number"], input[type="range"] {
  background: var(--control-surface);
  color: var(--control-text);
  border: 1px solid var(--control-border);
  border-radius: 6px;
  padding: 6px 10px;
}

button {
  cursor: pointer;
}

button.primary { background: var(--accent); color: var(--accent-contrast); border-color: transparent; }
button:disabled { opacity: 0.6; cursor: not-allowed; }

label { font-size: 13px; opacity: 0.9; }

.indicators { display: flex; gap: 16px; font-variant-numeric: tabular-nums; }
.indicators .pill { background: var(--pill-bg); padding: 4px 8px; border-radius: 999px; border: 1px solid var(--control-border); color: var(--control-text); }

/* Advanced subgroups spacing */
.group .subgroup { margin-top: 8px; display: grid; gap: 8px; }

/* Collapsible group header */
.group .group-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 8px;
}
.group .group-header > button {
  background: var(--control-surface);
  color: var(--control-text);
  border: 1px solid var(--control-border);
  border-radius: 6px;
  padding: 4px 8px;
  font-size: 12px;
}

.hidden { display: none !important; }
/* Analytics panel blocks */
#analytics .group { margin-bottom: 12px; }
#analytics .values { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 8px; }
#analytics .values div { background: var(--pill-bg); border: 1px solid var(--control-border); border-radius: 8px; padding: 8px; }
#analytics .table-wrap { max-height: 260px; overflow: auto; border: 1px solid var(--control-border); border-radius: 6px; }
#analytics table { width: 100%; border-collapse: collapse; font-size: 12px; }
#analytics th, #analytics td { padding: 4px 6px; border-bottom: 1px solid var(--control-border); text-align: right; }
#analytics th:first-child, #analytics td:first-child { text-align: left; }
#analytics canvas { width: 100%; height: 120px; display: block; background: transparent; border: 1px solid var(--control-border); border-radius: 6px; }
#analytics .chart-caption { font-size: 12px; opacity: 0.8; margin: 4px 2px 0 2px; }

/* Themed scrollbars (Firefox) */
html, #controls {
  scrollbar-width: thin; /* auto | thin | none */
  scrollbar-color: var(--control-border) var(--panel-bg); /* thumb track */
}

/* Themed scrollbars (WebKit: Chrome/Edge/Opera) */
/* Vertical/horizontal thickness */
body::-webkit-scrollbar, #controls::-webkit-scrollbar {
  width: 10px;
  height: 10px;
}
/* Track */
body::-webkit-scrollbar-track, #controls::-webkit-scrollbar-track {
  background: var(--panel-bg);
  border-left: 1px solid var(--panel-border);
}
/* Thumb */
body::-webkit-scrollbar-thumb, #controls::-webkit-scrollbar-thumb {
  background-color: var(--control-border);
  border-radius: 999px;
  border: 2px solid var(--panel-bg); /* creates gap to track */
}
/* Hover/active feedback */
body::-webkit-scrollbar-thumb:hover, #controls::-webkit-scrollbar-thumb:hover {
  background-color: var(--accent);
}
body::-webkit-scrollbar-thumb:active, #controls::-webkit-scrollbar-thumb:active {
  background-color: var(--accent);
}
/* Corner (when both scrolls) */
body::-webkit-scrollbar-corner, #controls::-webkit-scrollbar-corner {
  background: var(--panel-bg);
}

/* Styles for B/S rule selection UI */
.rule-selection {
  flex-direction: column;
  align-items: stretch;
  gap: 12px;
}

.bs-rule-container {
  display: flex;
  flex-direction: column;
  gap: 8px;
  border: 1px solid var(--control-border);
  border-radius: 6px;
  padding: 10px;
  background: var(--panel-bg);
}

.bs-rule-header {
  display: flex;
  align-items: center;
  margin-bottom: 4px;
}

.bs-rule-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
}

/* N Steps styling */
.n-steps-row {
  margin-top: 8px;
}

#inp-n-steps {
  width: 80px;
}

/* Progress message for N steps execution */
.simulation-progress {
  position: fixed;
  top: 20px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--panel-bg);
  border: 1px solid var(--panel-border);
  border-radius: 6px;
  padding: 12px 20px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.3);
  z-index: 1000;
  font-weight: bold;
}

.progress-text {
  color: var(--accent);
}

.rule-chip {
  display: inline-block;
  width: 32px;
  height: 32px;
  line-height: 32px;
  text-align: center;
  border-radius: 4px;
  cursor: pointer;
  font-weight: bold;
  background: var(--control-surface);
  border: 1px solid var(--control-border);
  user-select: none;
  transition: all 0.15s ease;
  color: #777;
}

.rule-chip:hover {
  border-color: var(--accent);
  color: var(--fg);
}

.rule-chip.selected {
  background: #2aaa3b;
  color: white;
  border-color: #1d8e2c;
  box-shadow: 0 0 6px rgba(42, 170, 59, 0.6);
  transform: scale(1.05);
}