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

:root {
  --bg: #0a0a0a;
  --surface: #141414;
  --surface2: #1e1e1e;
  --border: #2a2a2a;
  --text: #e0e0e0;
  --text-dim: #888;
  --accent: #7b8cff;
  --accent-dim: #4a5599;
  --radius: 8px;
}

body {
  font-family: -apple-system, "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

/* --- Header --- */

header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 24px;
  border-bottom: 1px solid var(--border);
}

header h1 {
  font-size: 20px;
  font-weight: 600;
  letter-spacing: 0.5px;
}

header h1 span {
  color: var(--accent);
}

/* --- Tabs --- */

.tabs {
  display: flex;
  gap: 4px;
  padding: 12px 24px 0;
}

.tab-btn {
  background: transparent;
  border: none;
  color: var(--text-dim);
  font-size: 14px;
  padding: 10px 20px;
  cursor: pointer;
  border-bottom: 2px solid transparent;
  transition: all 0.2s;
  font-family: inherit;
}

.tab-btn:hover {
  color: var(--text);
}

.tab-btn.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

/* --- Main layout --- */

.generator {
  display: none;
  padding: 20px 24px;
  gap: 24px;
}

.generator.active {
  display: flex;
}

@media (max-width: 900px) {
  .generator {
    flex-direction: column;
  }
}

/* --- Controls panel --- */

.controls {
  width: 280px;
  min-width: 280px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

@media (max-width: 900px) {
  .controls {
    width: 100%;
    min-width: unset;
    flex-direction: row;
    flex-wrap: wrap;
  }
  .control-group {
    flex: 1 1 200px;
  }
}

.control-group {
  padding: 8px 12px;
  background: var(--surface);
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

.control-group label {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 12px;
  color: var(--text-dim);
  margin-bottom: 6px;
}

.control-group label .value {
  color: var(--accent);
  font-variant-numeric: tabular-nums;
  font-weight: 500;
}

.control-group input[type="range"] {
  width: 100%;
  height: 4px;
  appearance: none;
  background: var(--surface2);
  border-radius: 2px;
  outline: none;
}

.control-group input[type="range"]::-webkit-slider-thumb {
  appearance: none;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--accent);
  cursor: pointer;
}

.control-group select {
  width: 100%;
  padding: 6px 8px;
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--text);
  font-size: 13px;
  font-family: inherit;
  cursor: pointer;
}

.control-group select:focus {
  outline: 1px solid var(--accent);
}

.control-group input[type="checkbox"] {
  accent-color: var(--accent);
}

.checkbox-row {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  cursor: pointer;
}

.control-group input[type="color"] {
  width: 32px;
  height: 24px;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: transparent;
  cursor: pointer;
  padding: 0;
}

/* --- Canvas area --- */

.canvas-area {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.canvas-wrap {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 8px;
  display: inline-block;
}

.canvas-wrap canvas {
  display: block;
  width: 512px;
  height: 512px;
  border-radius: 4px;
}

@media (max-width: 900px) {
  .canvas-wrap canvas {
    width: min(80vw, 512px);
    height: min(80vw, 512px);
  }
}

/* --- Info bar --- */

.info-bar {
  font-size: 12px;
  color: var(--text-dim);
  font-variant-numeric: tabular-nums;
  text-align: center;
  min-height: 18px;
}

/* --- Buttons --- */

.btn-row {
  display: flex;
  gap: 8px;
}

.btn {
  padding: 8px 20px;
  background: var(--accent-dim);
  border: none;
  border-radius: var(--radius);
  color: #fff;
  font-size: 13px;
  font-family: inherit;
  cursor: pointer;
  transition: background 0.15s;
}

.btn:hover {
  background: var(--accent);
}

.btn.secondary {
  background: var(--surface2);
  border: 1px solid var(--border);
}

.btn.secondary:hover {
  background: var(--border);
}

/* --- TIR warning --- */

.tir-warning {
  color: #ff6b6b;
  font-size: 12px;
  font-weight: 500;
}

/* --- Footer --- */

footer {
  text-align: center;
  padding: 24px;
  font-size: 12px;
  color: var(--text-dim);
  border-top: 1px solid var(--border);
  margin-top: 20px;
}

footer a {
  color: var(--accent);
  text-decoration: none;
}