:root {
  --bg: #1a1a1a;
  --fg: #e8e8e8;
  --dim: #888;
  --panel: #242424;
  --border: #333;
  --accent: #4a9eff;
  --accent-hover: #66b3ff;
}

* { box-sizing: border-box; }

html, body {
  margin: 0; padding: 0;
  background: var(--bg); color: var(--fg);
  font-family: -apple-system, system-ui, "Segoe UI", Roboto, sans-serif;
  font-size: 14px; line-height: 1.4;
  min-height: 100vh;
}

header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 12px 20px;
  border-bottom: 1px solid var(--border);
  background: var(--panel);
}
header h1 { margin: 0; font-size: 18px; font-weight: 500; }
.dim { color: var(--dim); font-weight: 300; }
.header-controls { display: flex; gap: 10px; align-items: center; }

.file-input {
  position: relative; display: inline-block;
  padding: 6px 12px;
  background: #333; border: 1px solid var(--border);
  border-radius: 4px; cursor: pointer;
}
.file-input:hover { background: #3a3a3a; }
.file-input input { display: none; }

button {
  padding: 6px 14px;
  background: var(--accent); color: white;
  border: none; border-radius: 4px;
  cursor: pointer; font-size: 14px;
}
button:hover:not(:disabled) { background: var(--accent-hover); }
button:disabled { background: #444; color: #888; cursor: not-allowed; }

main {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 320px;
  gap: 16px;
  padding: 16px 20px;
  max-width: 1400px;
  margin: 0 auto;
}

.preview-pane {
  display: flex; flex-direction: column;
  background: var(--panel);
  border: 1px solid var(--border); border-radius: 6px;
  padding: 12px;
  min-height: 520px;
}
#preview-canvas {
  flex: 1;
  width: 100%;
  height: auto;
  max-height: 640px;
  background: #2a2a2a;
  border-radius: 4px;
  object-fit: contain;
  image-rendering: pixelated;
}
.status {
  margin-top: 10px; color: var(--dim); font-size: 12px;
  min-height: 1.4em;
}

.controls-pane {
  background: var(--panel);
  border: 1px solid var(--border); border-radius: 6px;
  padding: 14px;
  overflow-y: auto;
  max-height: 80vh;
}
.control-group { margin-bottom: 14px; }
.control-group > label { display: block; margin-bottom: 4px; }
.slider-row { margin-bottom: 12px; }
.slider-row label {
  display: flex; justify-content: space-between;
  margin-bottom: 3px; font-size: 13px;
}
.slider-row .value { color: var(--accent); font-variant-numeric: tabular-nums; }
.slider-row input[type=range] {
  width: 100%; height: 6px;
}
.toggles label {
  display: flex; align-items: center; gap: 6px;
  padding: 4px 0; cursor: pointer;
}
.seed-row {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 8px;
}
.seed-row label { margin-bottom: 0; }
.seed-row input {
  background: #2a2a2a; color: var(--fg);
  border: 1px solid var(--border); border-radius: 4px;
  padding: 4px 8px; font-size: 13px;
}
select {
  width: 100%;
  background: #2a2a2a; color: var(--fg);
  border: 1px solid var(--border); border-radius: 4px;
  padding: 5px 8px; font-size: 13px;
}

footer {
  margin-top: 20px; padding: 12px 20px;
  border-top: 1px solid var(--border);
  color: var(--dim); font-size: 12px;
  text-align: center;
}
footer a { color: var(--accent); text-decoration: none; }
footer a:hover { text-decoration: underline; }

/* ---- Loading overlay (covers page until Pyodide worker is ready) ---- */
#loading-overlay {
  position: fixed; inset: 0; z-index: 9999;
  display: flex; align-items: center; justify-content: center;
  background: rgba(20, 20, 20, 0.96);
  backdrop-filter: blur(6px);
  transition: opacity 240ms ease;
}
#loading-overlay.hidden { opacity: 0; pointer-events: none; }
.loading-card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 28px 36px;
  text-align: center;
  max-width: 420px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.5);
}
.loading-card h2 { margin: 0 0 6px 0; font-size: 18px; font-weight: 500; }
.loading-card p { margin: 4px 0; color: var(--dim); }
.loading-card .loading-hint { font-size: 12px; margin-top: 14px; opacity: 0.7; }
.spinner {
  width: 36px; height: 36px;
  border: 3px solid #333;
  border-top-color: var(--accent);
  border-radius: 50%;
  margin: 0 auto 14px auto;
  animation: spin 0.9s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }