:root {
  --bg:     #1F0103;
  --panel:  #0c0f16;
  --line:   #1a1f2b;
  --text:   #c7cdd9;
  --dim:    #6a7384;
  --orange: #e8943a;
  --active: #1c2235;
  --mono:   "JetBrains Mono", "Fira Mono", Menlo, Consolas, monospace;
}

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

html, body {
  height: 100%;
  width: 100%;
  overflow: hidden;
  background: var(--bg);
  color: var(--text);
  font-family: var(--mono);
}

body {
  display: flex;
  flex-direction: row;
}

/* Stage fills everything left of the panel */
#stage {
  position: relative;
  flex: 1 1 auto;
  height: 100vh;
  background: var(--bg);
}

#gpu-canvas {
  display: block;
  width: 100%;
  height: 100%;
  cursor: default;
  touch-action: none;
}
#gpu-canvas:active { cursor: grabbing; }

#status {
  position: absolute;
  left: 14px;
  bottom: 12px;
  font-size: 11px;
  color: var(--dim);
  letter-spacing: 0.04em;
  pointer-events: none;
  text-shadow: 0 1px 3px rgba(0,0,0,0.8);
}
#status.error { color: #e86a6a; }

/* Right panel */
#panel {
  flex: 0 0 11.5%;
  min-width: 168px;
  max-width: 260px;
  height: 100vh;
  background: var(--panel);
  border-left: 1px solid var(--line);
  display: flex;
  flex-direction: column;
  overflow-y: auto;
}

.panel-head {
  padding: 14px 14px 10px;
  border-bottom: 1px solid var(--line);
}
.panel-head .title    { font-size: 11px; letter-spacing: 0.14em; color: var(--text); }
.panel-head .subtitle { font-size: 9px;  letter-spacing: 0.1em;  color: var(--dim);  margin-top: 3px; }

#metal-list {
  display: flex;
  flex-direction: column;
  padding: 6px 0;
  border-bottom: 1px solid var(--line);
}

.metal-item {
  display: grid;
  grid-template-columns: 28px 1fr auto;
  align-items: center;
  gap: 6px;
  width: 100%;
  padding: 7px 14px;
  background: none;
  border: none;
  border-left: 2px solid transparent;
  color: var(--text);
  font-family: var(--mono);
  font-size: 12px;
  text-align: left;
  cursor: pointer;
}
.metal-item:hover           { background: #1a0204; }
.metal-item.active          { background: var(--active); border-left-color: var(--orange); }
.metal-item .sym            { color: var(--orange); font-weight: 600; }
.metal-item .nm             { color: var(--text); }
.metal-item .z              { color: var(--dim); font-size: 10px; }

/* Grid controls */
.panel-section {
  border-bottom: 1px solid var(--line);
  padding: 8px 0 10px;
}

.section-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 4px 14px 8px;
}

.section-label {
  font-size: 10px;
  letter-spacing: 0.12em;
  color: var(--dim);
}

.toggle-btn {
  font-family: var(--mono);
  font-size: 9px;
  letter-spacing: 0.1em;
  padding: 2px 8px;
  background: none;
  border: 1px solid var(--line);
  border-radius: 2px;
  color: var(--dim);
  cursor: pointer;
}
.toggle-btn[data-on="true"] {
  color: #D00715;
  border-color: #D00715;
}

.ctrl-row {
  display: grid;
  grid-template-columns: 36px 1fr auto;
  align-items: center;
  gap: 6px;
  padding: 3px 14px;
}

.ctrl-label {
  font-size: 9px;
  letter-spacing: 0.1em;
  color: var(--dim);
}

.ctrl-val {
  font-size: 10px;
  color: var(--orange);
  text-align: right;
  justify-self: end;
  min-width: 22px;
}

input[type="range"] {
  grid-column: 1 / -1;
  width: 100%;
  accent-color: #D00715;
  height: 3px;
  cursor: pointer;
  margin-top: 4px;
}

/* Simulation / piece controls */
.piece-select {
  grid-column: 1 / -1;
  width: 100%;
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.06em;
  background: var(--panel);
  color: var(--text);
  border: 1px solid var(--line);
  border-radius: 2px;
  padding: 4px 6px;
  cursor: pointer;
  appearance: auto;
}
.piece-select:focus { outline: 1px solid #D00715; }

.sim-transport {
  display: flex;
  gap: 6px;
  padding: 6px 14px 2px;
  justify-content: flex-start;
}

.sim-btn {
  font-family: var(--mono);
  font-size: 10px;
  padding: 3px 9px;
  background: none;
  border: 1px solid var(--line);
  border-radius: 2px;
  color: var(--dim);
  cursor: pointer;
  letter-spacing: 0;
  line-height: 1;
}
.sim-btn:hover { color: var(--text); border-color: var(--text); }
.sim-play-btn[data-playing="true"] {
  color: #D00715;
  border-color: #D00715;
}

.step-label {
  padding: 4px 14px 6px;
  font-size: 9px;
  letter-spacing: 0.08em;
  color: var(--dim);
}

.panel-foot {
  margin-top: auto;
  padding: 12px 14px;
  font-size: 9px;
  color: var(--dim);
  line-height: 1.5;
  word-break: break-word;
}