:root {
  --bg: #0d0e14;
  --panel: #15171f;
  --panel-2: #1c1f29;
  --border: #2a2e3c;
  --text: #e8eaf0;
  --text-dim: #8a8fa3;
  --accent: #7c9aff;
  --accent-hover: #95aeff;
  --danger: #ff6b8a;
  --radius: 10px;
  --radius-sm: 6px;
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Inter", system-ui, sans-serif;
  --mono: "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
}

* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 14px;
  -webkit-font-smoothing: antialiased;
}

.app {
  display: flex;
  flex-direction: column;
  height: 100vh;
  overflow: hidden;
}

.app-header {
  padding: 16px 24px;
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

.app-header h1 {
  margin: 0;
  font-size: 18px;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.subtitle {
  margin: 2px 0 0;
  font-size: 12px;
  color: var(--text-dim);
}

.layout {
  flex: 1;
  display: grid;
  grid-template-columns: 1fr 420px;
  min-height: 0;
}

.preview-pane {
  display: flex;
  flex-direction: column;
  padding: 24px;
  gap: 16px;
  min-height: 0;
  overflow: hidden;
}

.preview-frame {
  flex: 1;
  min-height: 0;
  border-radius: var(--radius);
  overflow: hidden;
  background:
    linear-gradient(45deg, #1a1c25 25%, transparent 25%),
    linear-gradient(-45deg, #1a1c25 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, #1a1c25 75%),
    linear-gradient(-45deg, transparent 75%, #1a1c25 75%);
  background-size: 20px 20px;
  background-position: 0 0, 0 10px, 10px -10px, -10px 0;
  border: 1px solid var(--border);
}

.preview {
  width: 100%;
  height: 100%;
  position: relative;
  isolation: isolate;
}

.output {
  flex-shrink: 0;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.output-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 14px;
  border-bottom: 1px solid var(--border);
}

.output-header h2 {
  margin: 0;
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-dim);
}

.css-output {
  margin: 0;
  padding: 14px;
  font-family: var(--mono);
  font-size: 12px;
  line-height: 1.6;
  color: var(--text);
  max-height: 200px;
  overflow: auto;
  white-space: pre-wrap;
  word-break: break-all;
}

.controls {
  background: var(--panel);
  border-left: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  min-height: 0;
}

.layer-tabs {
  display: flex;
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

.tab {
  flex: 1;
  padding: 12px 16px;
  background: transparent;
  border: none;
  color: var(--text-dim);
  font-family: inherit;
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  border-bottom: 2px solid transparent;
  transition: color 0.15s, border-color 0.15s;
}

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

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

.panel {
  display: none;
  padding: 20px;
  overflow-y: auto;
  flex: 1;
}

.panel.active {
  display: block;
}

.row {
  margin-bottom: 18px;
}

.row.toggle-row {
  margin-bottom: 22px;
}

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

.field-label {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 8px;
  font-size: 12px;
  color: var(--text-dim);
  font-weight: 500;
}

.value-display {
  font-family: var(--mono);
  color: var(--text);
  font-size: 11px;
}

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

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 16px;
  height: 16px;
  background: var(--accent);
  border-radius: 50%;
  cursor: pointer;
  transition: background 0.15s;
}

input[type="range"]::-webkit-slider-thumb:hover {
  background: var(--accent-hover);
}

input[type="range"]::-moz-range-thumb {
  width: 16px;
  height: 16px;
  background: var(--accent);
  border-radius: 50%;
  cursor: pointer;
  border: none;
}

input[type="checkbox"] {
  -webkit-appearance: none;
  appearance: none;
  width: 36px;
  height: 20px;
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 10px;
  position: relative;
  cursor: pointer;
  transition: background 0.15s;
}

input[type="checkbox"]::after {
  content: "";
  position: absolute;
  width: 14px;
  height: 14px;
  background: var(--text-dim);
  border-radius: 50%;
  top: 2px;
  left: 2px;
  transition: transform 0.2s, background 0.15s;
}

input[type="checkbox"]:checked {
  background: var(--accent);
  border-color: var(--accent);
}

input[type="checkbox"]:checked::after {
  background: white;
  transform: translateX(16px);
}

select {
  width: 100%;
  padding: 8px 10px;
  background: var(--panel-2);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-family: inherit;
  font-size: 13px;
  outline: none;
  cursor: pointer;
}

select:focus {
  border-color: var(--accent);
}

input[type="color"] {
  width: 40px;
  height: 32px;
  padding: 0;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: transparent;
  cursor: pointer;
}

input[type="color"]::-webkit-color-swatch-wrapper {
  padding: 2px;
}

input[type="color"]::-webkit-color-swatch {
  border: none;
  border-radius: 4px;
}

input[type="text"] {
  padding: 8px 10px;
  background: var(--panel-2);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-family: var(--mono);
  font-size: 12px;
  outline: none;
  width: 100%;
}

input[type="text"]:focus {
  border-color: var(--accent);
}

.segmented {
  display: flex;
  gap: 4px;
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 3px;
  margin-bottom: 10px;
}

.segmented button {
  flex: 1;
  padding: 6px 10px;
  background: transparent;
  border: none;
  color: var(--text-dim);
  font-family: inherit;
  font-size: 12px;
  font-weight: 500;
  border-radius: 4px;
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
  white-space: nowrap;
}

.segmented button:hover {
  color: var(--text);
}

.segmented button.active {
  background: var(--accent);
  color: white;
}

.btn {
  padding: 7px 12px;
  background: var(--accent);
  color: white;
  border: none;
  border-radius: var(--radius-sm);
  font-family: inherit;
  font-size: 12px;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.15s;
}

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

.btn-ghost {
  background: transparent;
  color: var(--text-dim);
  border: 1px solid var(--border);
}

.btn-ghost:hover {
  background: var(--panel-2);
  color: var(--text);
}

.btn-small {
  padding: 4px 8px;
  font-size: 11px;
}

.btn-icon {
  width: 24px;
  height: 24px;
  padding: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: transparent;
  color: var(--text-dim);
  border: 1px solid var(--border);
  border-radius: 4px;
  cursor: pointer;
  font-size: 14px;
  line-height: 1;
}

.btn-icon:hover {
  color: var(--danger);
  border-color: var(--danger);
}

.stops-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 10px;
}

.stops-header .field-label {
  margin-bottom: 0;
}

.stops {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.stop {
  display: grid;
  grid-template-columns: 40px 1fr 56px 24px;
  align-items: center;
  gap: 8px;
  padding: 8px;
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
}

.stop input[type="range"] {
  margin: 0;
}

.stop-position {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--text-dim);
  text-align: right;
}

.hint {
  margin: 0;
  padding: 10px 12px;
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 12px;
  color: var(--text-dim);
  line-height: 1.5;
}

[data-show-for] {
  display: none;
}

[data-show-for].visible {
  display: block;
}

@media (max-width: 900px) {
  .layout {
    grid-template-columns: 1fr;
    grid-template-rows: 1fr auto;
  }
  .controls {
    border-left: none;
    border-top: 1px solid var(--border);
    max-height: 50vh;
  }
}