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

body {
  padding: 8px;
  overflow: hidden;
  user-select: none;
  -webkit-user-select: none;
}

/* ---- Layout ---- */
#app {
  display: grid;
  grid-template-columns: 1fr 200px;
  grid-template-rows: 1fr auto auto;
  grid-template-areas:
    "visual  panel"
    "palette palette"
    "footer  footer";
  gap: 8px;
  height: calc(100vh - 16px);
}

#visual-area {
  grid-area: visual;
  display: flex;
  gap: 8px;
  min-height: 0;
  min-width: 0;
}

#sv-wrap {
  position: relative;
  flex: 1;
  min-width: 100px;
  min-height: 100px;
  border: 2px inset;
  border-color: var(--sz-color-button-shadow) var(--sz-color-button-highlight) var(--sz-color-button-highlight) var(--sz-color-button-shadow);
  cursor: crosshair;
}

#sv-canvas {
  display: block;
  width: 100%;
  height: 100%;
}

#sv-cursor {
  position: absolute;
  width: 12px;
  height: 12px;
  border: 2px solid #fff;
  border-radius: 50%;
  box-shadow: 0 0 0 1px #000, inset 0 0 0 1px #000;
  pointer-events: none;
  transform: translate(-50%, -50%);
}

#hue-wrap {
  position: relative;
  width: 24px;
  flex-shrink: 0;
  border: 2px inset;
  border-color: var(--sz-color-button-shadow) var(--sz-color-button-highlight) var(--sz-color-button-highlight) var(--sz-color-button-shadow);
  cursor: pointer;
}

#hue-canvas {
  display: block;
  width: 100%;
  height: 100%;
}

#hue-slider {
  position: absolute;
  left: -2px;
  right: -2px;
  height: 4px;
  border: 1px solid #000;
  background: #fff;
  pointer-events: none;
  transform: translateY(-50%);
}

#alpha-wrap {
  position: relative;
  width: 24px;
  flex-shrink: 0;
  border: 2px inset;
  border-color: var(--sz-color-button-shadow) var(--sz-color-button-highlight) var(--sz-color-button-highlight) var(--sz-color-button-shadow);
  cursor: pointer;
  background-image:
    linear-gradient(45deg, #ccc 25%, transparent 25%),
    linear-gradient(-45deg, #ccc 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, #ccc 75%),
    linear-gradient(-45deg, transparent 75%, #ccc 75%);
  background-size: 8px 8px;
  background-position: 0 0, 0 4px, 4px -4px, -4px 0;
}

#alpha-canvas {
  display: block;
  width: 100%;
  height: 100%;
  position: relative;
  z-index: 1;
}

#alpha-slider {
  position: absolute;
  left: -2px;
  right: -2px;
  height: 4px;
  border: 1px solid #000;
  background: #fff;
  pointer-events: none;
  transform: translateY(-50%);
  z-index: 2;
}

/* ---- Color wheel area ---- */
#wheel-area {
  grid-area: visual;
  display: flex;
  gap: 8px;
  min-height: 0;
  min-width: 0;
  align-items: center;
  justify-content: center;
}

#wheel-area.hidden {
  display: none;
}

#visual-area.hidden {
  display: none;
}

#wheel-wrap {
  position: relative;
  width: 200px;
  height: 200px;
  flex-shrink: 0;
  cursor: crosshair;
}

#wheel-canvas {
  display: block;
  width: 100%;
  height: 100%;
  border-radius: 50%;
}

#wheel-cursor {
  position: absolute;
  width: 12px;
  height: 12px;
  border: 2px solid #fff;
  border-radius: 50%;
  box-shadow: 0 0 0 1px #000, inset 0 0 0 1px #000;
  pointer-events: none;
  transform: translate(-50%, -50%);
}

#lv-wrap {
  position: relative;
  width: 24px;
  height: 200px;
  flex-shrink: 0;
  border: 2px inset;
  border-color: var(--sz-color-button-shadow) var(--sz-color-button-highlight) var(--sz-color-button-highlight) var(--sz-color-button-shadow);
  cursor: pointer;
}

#lv-canvas {
  display: block;
  width: 100%;
  height: 100%;
}

#lv-slider {
  position: absolute;
  left: -2px;
  right: -2px;
  height: 4px;
  border: 1px solid #000;
  background: #fff;
  pointer-events: none;
  transform: translateY(-50%);
}

#wheel-alpha-wrap {
  position: relative;
  width: 24px;
  height: 200px;
  flex-shrink: 0;
  border: 2px inset;
  border-color: var(--sz-color-button-shadow) var(--sz-color-button-highlight) var(--sz-color-button-highlight) var(--sz-color-button-shadow);
  cursor: pointer;
  background-image:
    linear-gradient(45deg, #ccc 25%, transparent 25%),
    linear-gradient(-45deg, #ccc 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, #ccc 75%),
    linear-gradient(-45deg, transparent 75%, #ccc 75%);
  background-size: 8px 8px;
  background-position: 0 0, 0 4px, 4px -4px, -4px 0;
}

#wheel-alpha-canvas {
  display: block;
  width: 100%;
  height: 100%;
  position: relative;
  z-index: 1;
}

#wheel-alpha-slider {
  position: absolute;
  left: -2px;
  right: -2px;
  height: 4px;
  border: 1px solid #000;
  background: #fff;
  pointer-events: none;
  transform: translateY(-50%);
  z-index: 2;
}

/* ---- Right side panel ---- */
#right-panel {
  grid-area: panel;
  display: flex;
  flex-direction: column;
  gap: 6px;
  min-height: 0;
  min-width: 0;
  overflow-y: auto;
}

/* ---- Preview ---- */
#preview-area {
  display: flex;
  gap: 4px;
  align-items: stretch;
  height: 44px;
}

#preview-area > div {
  flex: 1;
  min-width: 0;
}

#eyedropper-group {
  display: flex;
  flex-direction: column;
  gap: 1px;
  flex-shrink: 0;
  align-items: center;
}

#btn-eyedropper {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  flex: 1;
  padding: 0;
  cursor: pointer;
}

#btn-eyedropper svg {
  display: block;
}

#sample-size {
  width: 28px;
  font-size: 7px;
  padding: 0;
  text-align: center;
  cursor: default;
  flex-shrink: 0;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
  pointer-events: none;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
}

.preview-box {
  flex: 1;
  border: 2px inset;
  border-color: var(--sz-color-button-shadow) var(--sz-color-button-highlight) var(--sz-color-button-highlight) var(--sz-color-button-shadow);
  position: relative;
  overflow: hidden;
}

.preview-box .checker {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(45deg, #ccc 25%, transparent 25%),
    linear-gradient(-45deg, #ccc 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, #ccc 75%),
    linear-gradient(-45deg, transparent 75%, #ccc 75%);
  background-size: 8px 8px;
  background-position: 0 0, 0 4px, 4px -4px, -4px 0;
}

.preview-box .swatch {
  position: absolute;
  inset: 0;
}

.preview-label {
  font-size: 9px;
  text-align: center;
  color: var(--sz-color-gray-text);
}

/* ---- Tabs ---- */
#tab-bar {
  display: flex;
  gap: 0;
  border-bottom: 1px solid var(--sz-color-button-shadow);
  flex-shrink: 0;
}

.tab-btn {
  padding: 2px 6px;
  font-size: 10px;
  font-family: inherit;
  cursor: default;
  border: 1px solid var(--sz-color-button-shadow);
  border-bottom: none;
  background: var(--sz-color-button-face);
  color: var(--sz-color-button-text);
  margin-bottom: -1px;
  position: relative;
}

.tab-btn.active {
  background: var(--sz-color-window);
  border-bottom: 1px solid var(--sz-color-window);
  z-index: 1;
  font-weight: bold;
}

#tab-content {
  background: var(--sz-color-window);
  border: 1px solid var(--sz-color-button-shadow);
  border-top: none;
  padding: 4px;
  flex: 1 1 0;
  min-height: 60px;
  overflow-y: auto;
}

.tab-panel { display: none; }
.tab-panel.active { display: block; }

/* ---- Sliders ---- */
.slider-row {
  display: grid;
  grid-template-columns: 16px 1fr 42px;
  gap: 4px;
  align-items: center;
  margin-bottom: 3px;
}

.slider-row label {
  font-weight: bold;
  font-size: 10px;
  text-align: right;
}

.slider-row input[type="range"] {
  width: 100%;
  height: 14px;
  -webkit-appearance: none;
  appearance: none;
  background: transparent;
  cursor: pointer;
}

.slider-row input[type="range"]::-webkit-slider-runnable-track {
  height: 6px;
  border: 1px solid var(--sz-color-button-shadow);
  background: var(--sz-color-window);
}

.slider-row input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 10px;
  height: 16px;
  background: var(--sz-color-button-face);
  border: 1px solid var(--sz-color-button-shadow);
  margin-top: -6px;
  cursor: pointer;
}

.slider-row input[type="range"]::-moz-range-track {
  height: 6px;
  border: 1px solid var(--sz-color-button-shadow);
  background: var(--sz-color-window);
}

.slider-row input[type="range"]::-moz-range-thumb {
  width: 10px;
  height: 16px;
  background: var(--sz-color-button-face);
  border: 1px solid var(--sz-color-button-shadow);
  cursor: pointer;
  border-radius: 0;
}

.slider-row input[type="number"] {
  width: 42px;
  font-size: 10px;
  text-align: right;
  padding: 1px 2px;
}

/* ---- Hex / CSS row ---- */
.hex-row {
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: 4px;
  align-items: center;
  margin-bottom: 3px;
}

.hex-row label {
  font-weight: bold;
  font-size: 10px;
}

.hex-row input[type="text"] {
  font-family: 'Lucida Console', 'Consolas', monospace;
  font-size: 10px;
  padding: 1px 3px;
  width: 100%;
}

.hex-row button {
  font-size: 9px;
  padding: 1px 4px;
  min-width: 0;
}

.section-label {
  font-weight: bold;
  font-size: 10px;
  margin: 4px 0 2px;
  color: var(--sz-color-button-text);
}

/* ---- Palette ---- */
#palette-area {
  grid-area: palette;
  min-height: 0;
  overflow-y: auto;
}

.palette-section-label {
  font-size: 9px;
  font-weight: bold;
  margin-bottom: 2px;
  color: var(--sz-color-button-text);
}

.palette-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 2px;
  margin-bottom: 4px;
}

.palette-swatch {
  width: 16px;
  height: 16px;
  border: 1px solid var(--sz-color-button-shadow);
  cursor: pointer;
}

.palette-swatch:hover {
  border-color: var(--sz-color-button-text);
  outline: 1px solid var(--sz-color-button-highlight);
}

.palette-swatch.empty {
  background-image:
    linear-gradient(45deg, #ccc 25%, transparent 25%),
    linear-gradient(-45deg, #ccc 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, #ccc 75%),
    linear-gradient(-45deg, transparent 75%, #ccc 75%);
  background-size: 6px 6px;
  background-position: 0 0, 0 3px, 3px -3px, -3px 0;
}

#palette-buttons {
  display: flex;
  gap: 4px;
  margin-top: 2px;
}

#palette-buttons button {
  font-size: 10px;
  padding: 2px 6px;
}

/* ---- Float display ---- */
.float-grid {
  display: grid;
  grid-template-columns: 16px 1fr;
  gap: 2px 4px;
  align-items: center;
  margin-bottom: 3px;
}

.float-grid label {
  font-weight: bold;
  font-size: 10px;
  text-align: right;
}

.float-grid input[type="text"] {
  font-family: 'Lucida Console', 'Consolas', monospace;
  font-size: 10px;
  padding: 1px 3px;
}

/* ---- Dialog footer (OK / Cancel) ---- */
#dialog-footer {
  grid-area: footer;
  display: flex;
  justify-content: flex-end;
  gap: 6px;
  padding: 6px 0 2px;
  border-top: 1px solid var(--sz-color-button-shadow);
}

#dialog-footer button {
  min-width: 72px;
  padding: 4px 14px;
  font-size: 11px;
  font-family: inherit;
  cursor: default;
}