/* === Reset & Base === */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --header-h: 44px;
  --info-h: 32px;
  --panel-w: 280px;
  --bg: #1a1a2e;
  --bg-panel: #16213e;
  --text: #e0e0e0;
  --accent: #0f3460;
  --accent-light: #537ec5;
  --border: #2a2a4a;
}

html, body {
  height: 100%;
  overflow: hidden;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  font-size: 14px;
  background: var(--bg);
  color: var(--text);
  touch-action: none;
  -webkit-user-select: none;
  user-select: none;
}

/* === Header === */
#header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-h);
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 0 10px;
  background: rgba(22, 33, 62, 0.92);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  z-index: 100;
  border-bottom: 1px solid var(--border);
}

#app-title {
  font-size: 15px;
  font-weight: 600;
  flex: 1;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.header-right {
  display: flex;
  align-items: center;
  gap: 6px;
}

/* === Buttons === */
.icon-btn {
  background: none;
  border: none;
  color: var(--text);
  font-size: 20px;
  cursor: pointer;
  padding: 4px 8px;
  border-radius: 4px;
  line-height: 1;
}

.icon-btn:hover {
  background: rgba(255, 255, 255, 0.1);
}

.text-btn {
  background: var(--accent);
  border: 1px solid var(--accent-light);
  color: var(--text);
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
  padding: 3px 10px;
  border-radius: 4px;
}

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

.action-btn {
  width: 100%;
  padding: 8px;
  margin-top: 6px;
  background: var(--accent);
  border: 1px solid var(--accent-light);
  color: var(--text);
  font-size: 13px;
  border-radius: 4px;
  cursor: pointer;
}

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

/* === Side Panel === */
.overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.4);
  z-index: 199;
}

.side-panel {
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  width: var(--panel-w);
  background: var(--bg-panel);
  border-right: 1px solid var(--border);
  z-index: 200;
  overflow-y: auto;
  padding: calc(var(--header-h) + 12px) 14px 14px;
  transform: translateX(0);
  transition: transform 0.25s ease;
}

.side-panel.hidden {
  transform: translateX(calc(-1 * var(--panel-w) - 1px));
}

.overlay.hidden {
  display: none;
}

.panel-section {
  margin-bottom: 18px;
}

.panel-section > label:first-child {
  display: block;
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--accent-light);
  margin-bottom: 6px;
}

.panel-section select {
  width: 100%;
  padding: 6px 8px;
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 4px;
  font-size: 13px;
}

/* Julia params */
.julia-inputs {
  display: flex;
  gap: 8px;
}

.julia-inputs label {
  flex: 1;
  font-size: 12px;
}

.julia-inputs input {
  width: 100%;
  padding: 4px 6px;
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 4px;
  font-size: 13px;
  margin-top: 2px;
}

/* Palette grid */
.palette-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 6px;
}

.palette-swatch {
  height: 32px;
  border-radius: 4px;
  cursor: pointer;
  border: 2px solid transparent;
  transition: border-color 0.15s;
}

.palette-swatch.active {
  border-color: #fff;
}

.palette-swatch:hover {
  border-color: var(--accent-light);
}

/* Slider */
.slider-row {
  display: flex;
  align-items: center;
  gap: 8px;
}

.slider-row input[type="range"] {
  flex: 1;
  accent-color: var(--accent-light);
}

.slider-row span {
  min-width: 42px;
  text-align: right;
  font-size: 13px;
  font-variant-numeric: tabular-nums;
}

/* === Canvas === */
#fractal-canvas {
  position: fixed;
  top: var(--header-h);
  left: 0;
  right: 0;
  bottom: var(--info-h);
  width: 100%;
  height: calc(100% - var(--header-h) - var(--info-h));
  display: block;
}

/* === Info Bar === */
#info-bar {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  height: var(--info-h);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  padding: 0 12px;
  background: rgba(22, 33, 62, 0.92);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  font-size: 12px;
  font-variant-numeric: tabular-nums;
  color: #aab;
  z-index: 100;
  border-top: 1px solid var(--border);
}

/* === Toast === */
.toast {
  position: fixed;
  bottom: calc(var(--info-h) + 16px);
  left: 50%;
  transform: translateX(-50%);
  background: var(--accent-light);
  color: #fff;
  padding: 8px 20px;
  border-radius: 6px;
  font-size: 13px;
  z-index: 300;
  opacity: 1;
  transition: opacity 0.4s;
}

.toast.hidden {
  opacity: 0;
  pointer-events: none;
}

/* === Responsive (small screens) === */
@media (max-width: 767px) {
  :root {
    --panel-w: 260px;
  }

  #info-bar {
    gap: 8px;
    font-size: 11px;
  }

  #app-title {
    font-size: 13px;
  }
}

@media (max-width: 400px) {
  #info-bar {
    gap: 4px;
    font-size: 10px;
    padding: 0 6px;
  }
}