:root {
  color-scheme: light;

  /* Color tokens */
  --color-bg: #ffffff;
  --color-surface: #ffffff;
  --color-surface-muted: #f6f6f6;
  --color-surface-subtle: #f1f1f1;
  --color-border: #e6e6e6;
  --color-border-muted: #e1e1e1;
  --color-border-strong: #d4d4d4;
  --color-border-hover: #cfcfcf;
  --color-border-focus: #bdbdbd;
  --color-text-primary: #111111;
  --color-text-secondary: #5f6368;
  --color-text-muted: #6d7076;
  --color-text-subtle: #8a8d92;
  --color-heading: #1f1f20;
  --color-interactive: #3b3b3d;
  --color-interactive-hover: #1f1f20;
  --color-icon: #5e6166;
  --color-aspect-border: #9aa0ab;
  --color-aspect-border-active: #4a4f57;
  --color-range-track: #e5e5e5;
  --color-range-progress: #111111;
  --color-panel-border: #e8e8e8;
  --color-focus-ring: rgba(17, 17, 17, 0.2);

  /* Spacing */
  --space-2xs: 0.15rem;
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 0.75rem;
  --space-lg: 1rem;
  --space-xl: 1.5rem;
  --space-2xl: 1.75rem;

  /* Radii */
  --radius-sm: 0.5rem;
  --radius-md: 0.75rem;
  --radius-lg: 1rem;
  --radius-full: 999px;

  /* Component metrics */
  --tabs-offset: 0.35rem;
  --tab-padding-y: 0.4rem;
  --tab-padding-x: 1.2rem;
  --tab-gap: var(--space-xs);
  --button-padding-y: 0.55rem;
  --button-padding-x: 1.4rem;
  --button-min-width: 7.5rem;
  --chip-padding-y: 0.3rem;
  --dropdown-padding-y: 0.5rem;
  --dropdown-padding-x: 0.85rem;
  --dropdown-gap: 0.75rem;
  --dropdown-option-padding-y: 0.45rem;
  --dropdown-option-padding-x: 1rem;
  --dropdown-option-padding-left: 2.25rem;
  --color-item-padding-y: 0.55rem;
  --color-item-padding-x: 0.75rem;
  --color-item-gap: 0.75rem;
  --slider-track-height: 0.375rem;
  --slider-thumb-size: 1rem;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(15, 15, 15, 0.08);
  --shadow-md: 0 1px 3px rgba(15, 15, 15, 0.1);
  --shadow-lg: 0 2px 6px rgba(15, 15, 15, 0.08);
  --shadow-card: 0 18px 42px rgba(15, 15, 15, 0.06), 0 1px 3px rgba(15, 15, 15, 0.08);
  --shadow-canvas: 0 20px 50px rgba(15, 15, 15, 0.08), 0 1px 2px rgba(15, 15, 15, 0.08);
  --shadow-dropdown: 0 20px 45px rgba(15, 15, 15, 0.12), 0 2px 6px rgba(15, 15, 15, 0.08);
  --shadow-inset-subtle: inset 0 1px 0 rgba(255, 255, 255, 0.65);
  --shadow-inset-strong: inset 0 1px 0 rgba(255, 255, 255, 0.85);

  /* Typography */
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.8rem;
  --font-size-tab: 0.85rem;
  --font-size-base: 0.9rem;
  --font-size-lg: 0.95rem;
  --font-size-xl: 1.45rem;
  --font-weight-normal: 300;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;

  /* Motion */
  --transition-fast: 0.15s ease;
  --transition-base: 0.2s ease;

  /* Layers */
  --z-tabs: 1;
  --z-dropdown: 10;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--color-bg);
  color: var(--color-text-primary);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

header p a {
  color: var(--color-text-muted);
  text-decoration-color: var(--color-text-muted);
  transition: color var(--transition-base), text-decoration-color var(--transition-base);
}

header p a:hover {
  color: var(--color-text-secondary);
  text-decoration-color: var(--color-text-secondary);
}

header p a:focus-visible {
  outline: 2px solid var(--color-focus-ring);
  outline-offset: 2px;
}

header {
  padding: var(--space-lg) var(--space-xl) var(--space-sm);
  display: grid;
  grid-template-columns: minmax(0, 1fr) 20rem;
  column-gap: var(--space-xl);
  row-gap: var(--space-xs);
}

header h1 {
  margin: 0;
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-semibold);
  letter-spacing: -0.01em;
  grid-column: 1 / 2;
}

header p {
  margin: var(--space-2xs) 0 0;
  font-size: var(--font-size-lg);
  line-height: 1.5;
  color: var(--color-text-secondary);
  grid-column: 1 / 2;
}

#app {
  flex: 1;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 20rem;
  gap: var(--space-xl);
  padding: 0 var(--space-xl) var(--space-xl);
}

canvas {
  width: 100%;
  height: var(--canvas-height, 45.25rem);
  display: block;
  align-self: start;
  border-radius: var(--radius-lg);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-canvas);
}

.control-pane {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
  align-items: flex-start;
}

.controls-card {
  padding: var(--space-2xl) var(--space-xl) var(--space-xl);
  border-radius: var(--radius-lg);
  background: var(--color-surface);
  border: 1px solid var(--color-panel-border);
  box-shadow: var(--shadow-card);
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
  width: 100%;
}

.tabs {
  display: inline-flex;
  align-items: center;
  gap: var(--tab-gap);
  padding: var(--space-xs) var(--space-sm);
  background: var(--color-surface-subtle);
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border-muted);
  box-shadow: var(--shadow-inset-subtle);
  margin: 0;
  margin-bottom: calc(-1 * var(--tabs-offset));
  position: relative;
  z-index: var(--z-tabs);
}

.tab {
  border: 1px solid transparent;
  background: transparent;
  color: var(--color-interactive);
  border-radius: var(--radius-sm);
  padding: var(--tab-padding-y) var(--tab-padding-x);
  font-size: var(--font-size-tab);
  font-weight: var(--font-weight-semibold);
  cursor: pointer;
  transition:
    background var(--transition-base),
    color var(--transition-base),
    box-shadow var(--transition-base);
}

.tab:hover {
  background: rgba(255, 255, 255, 0.7);
}

.tab:focus-visible {
  outline: 2px solid var(--color-focus-ring);
  outline-offset: 2px;
}

.tab-active {
  background: var(--color-surface);
  color: var(--color-text-primary);
  box-shadow: var(--shadow-md), inset 0 0 0 1px var(--color-border-strong);
  border-color: var(--color-border-strong);
}

.panel {
  display: none;
  flex-direction: column;
  gap: var(--space-2xl);
}

.panel-active {
  display: flex;
}

.download-status {
  margin: 0;
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  min-height: 1.25rem;
}

.color-grid {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.color-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--color-item-gap);
  padding: var(--color-item-padding-y) var(--color-item-padding-x);
  background: var(--color-surface-muted);
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border-strong);
}

.color-item input[type='color'] {
  width: 3rem;
  height: 2rem;
  border: none;
  background: transparent;
  cursor: pointer;
}

.color-item button {
  border: 1px solid var(--color-border-strong);
  background: var(--color-surface);
  color: var(--color-interactive);
  padding: var(--chip-padding-y) var(--space-md);
  border-radius: var(--radius-full);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
  cursor: pointer;
  transition:
    background var(--transition-base),
    color var(--transition-base),
    box-shadow var(--transition-base),
    border-color var(--transition-base);
}

.color-item button:hover {
  background: var(--color-surface-subtle);
}

.control {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
  font-size: var(--font-size-base);
}

.control-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: var(--space-2xl);
}

.control > label,
.control-header > label,
.control-label {
  font-weight: var(--font-weight-medium);
  color: var(--color-heading);
}

.control-label {
  display: inline-block;
  margin-bottom: calc(var(--space-sm) - var(--space-2xs));
}

.control-value {
  font-size: var(--font-size-tab);
  font-weight: var(--font-weight-normal);
  color: var(--color-text-muted);
}

.control input[type='range'],
.control input[type='color'],
.control select {
  width: 100%;
}

.dropdown {
  position: relative;
  width: 100%;
}

.dropdown-trigger {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--dropdown-gap);
  border-radius: var(--radius-md);
  padding: var(--dropdown-padding-y) var(--dropdown-padding-x);
  border: 1px solid var(--color-border-strong);
  background: var(--color-surface);
  color: var(--color-heading);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-medium);
  box-shadow: var(--shadow-inset-strong), var(--shadow-sm);
  cursor: pointer;
  transition:
    box-shadow var(--transition-base),
    border-color var(--transition-base),
    background var(--transition-base);
}

.dropdown-trigger:hover {
  border-color: var(--color-border-hover);
  box-shadow: var(--shadow-inset-strong), var(--shadow-lg);
}

.dropdown-trigger:focus-visible {
  outline: 2px solid var(--color-focus-ring);
  outline-offset: 2px;
}

.dropdown-trigger svg {
  color: var(--color-icon);
  transition: transform var(--transition-base);
}

.dropdown.open .dropdown-trigger svg {
  transform: rotate(180deg);
}

.dropdown.open .dropdown-trigger {
  border-color: var(--color-border-focus);
}

.dropdown-list {
  list-style: none;
  margin: 0;
  padding: var(--dropdown-option-padding-y) 0;
  position: absolute;
  top: calc(100% + var(--space-sm));
  left: 0;
  right: 0;
  display: none;
  background: var(--color-surface);
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-dropdown);
  z-index: var(--z-dropdown);
}

.dropdown.open .dropdown-list {
  display: block;
}

.dropdown-option {
  width: 100%;
  border: none;
  background: transparent;
  text-align: left;
  padding:
    var(--dropdown-option-padding-y)
    var(--dropdown-option-padding-x)
    var(--dropdown-option-padding-y)
    var(--dropdown-option-padding-left);
  font-size: var(--font-size-base);
  color: var(--color-heading);
  cursor: pointer;
  position: relative;
  transition: background var(--transition-fast), color var(--transition-fast);
}

.dropdown-option:hover {
  background: var(--color-surface-muted);
}

.dropdown-option.selected {
  color: var(--color-text-primary);
  font-weight: var(--font-weight-medium);
}

.dropdown-option.selected::before {
  content: '\2713';
  position: absolute;
  left: var(--dropdown-option-padding-x);
  top: 50%;
  transform: translateY(-50%);
  font-size: var(--font-size-xs);
  color: var(--color-text-primary);
}

.control input[type='range'] {
  accent-color: var(--color-range-progress);
  height: var(--slider-track-height);
  -webkit-appearance: none;
  background: transparent;
}

.control input[type='range']::-webkit-slider-runnable-track {
  height: var(--slider-track-height);
  border-radius: var(--radius-full);
  background: linear-gradient(
    to right,
    var(--color-range-progress) var(--progress, 50%),
    var(--color-range-track) var(--progress, 50%)
  );
}

.control input[type='range']::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: var(--slider-thumb-size);
  height: var(--slider-thumb-size);
  border-radius: 50%;
  border: 1px solid var(--color-range-progress);
  background: var(--color-surface);
  margin-top: calc((var(--slider-track-height) - var(--slider-thumb-size)) / 2);
  transition: transform var(--transition-fast);
}

.control input[type='range']::-webkit-slider-thumb:hover {
  transform: scale(1.05);
}

.control input[type='range']::-moz-range-track {
  height: var(--slider-track-height);
  border-radius: var(--radius-full);
  background: var(--color-range-track);
}

.control input[type='range']::-moz-range-progress {
  background: var(--color-range-progress);
  border-radius: var(--radius-full);
  height: var(--slider-track-height);
}

.control input[type='range']::-moz-range-thumb {
  width: var(--slider-thumb-size);
  height: var(--slider-thumb-size);
  border: 1px solid var(--color-range-progress);
  border-radius: 50%;
  background: var(--color-surface);
  transition: transform var(--transition-fast);
}

.control input[type='range']::-moz-range-thumb:hover {
  transform: scale(1.05);
}

.toggles {
  display: flex;
  gap: var(--space-sm);
  align-items: center;
}

.toggles label {
  display: flex;
  gap: var(--space-sm);
  align-items: center;
  font-weight: var(--font-weight-medium);
  font-size: var(--font-size-tab);
}

.button {
  appearance: none;
  border-radius: var(--radius-md);
  padding: var(--button-padding-y) var(--button-padding-x);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-semibold);
  cursor: pointer;
  border: 1px solid var(--color-border-strong);
  background: var(--color-surface);
  color: var(--color-heading);
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  min-width: var(--button-min-width);
  justify-content: center;
  box-shadow: var(--shadow-inset-strong), var(--shadow-sm);
  transition:
    transform var(--transition-fast),
    box-shadow var(--transition-fast),
    background var(--transition-base),
    border-color var(--transition-base),
    color var(--transition-base);
}

.button:hover {
  background: var(--color-surface-subtle);
  border-color: var(--color-border-hover);
  box-shadow: var(--shadow-inset-strong), var(--shadow-lg);
}

.button:focus-visible {
  outline: 2px solid var(--color-focus-ring);
  outline-offset: 2px;
}

.button svg {
  width: 0.875rem;
  height: 0.875rem;
  color: var(--color-icon);
  pointer-events: none;
}

.control-footer {
  width: 100%;
  padding: var(--space-lg) 0 0;
  font-size: var(--font-size-sm);
  color: var(--color-text-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-lg);
  margin-top: auto;
}

.control-footer a:not(.footer-github) {
  color: var(--color-text-muted);
  text-decoration-color: var(--color-text-muted);
  transition: color var(--transition-base), text-decoration-color var(--transition-base);
}

.control-footer a:not(.footer-github):hover {
  color: var(--color-text-secondary);
  text-decoration-color: var(--color-text-secondary);
}

.control-footer a:not(.footer-github):focus-visible {
  outline: 2px solid var(--color-focus-ring);
  outline-offset: 2px;
}

.footer-github {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  text-decoration: none;
  color: var(--color-text-muted);
  font-weight: var(--font-weight-medium);
  transition: color var(--transition-base), opacity var(--transition-base);
}

.footer-github:hover {
  color: var(--color-text-secondary);
  opacity: 0.95;
}

.footer-github:focus-visible {
  outline: 2px solid var(--color-focus-ring);
  outline-offset: 3px;
}

.footer-github-icon {
  width: 1.1rem;
  height: 1.1rem;
  display: block;
}

@media (max-width: 60rem) {
  header {
    grid-template-columns: 1fr;
  }

  #app {
    grid-template-columns: 1fr;
  }

  .control-pane {
    order: -1;
  }
}

.aspect-tab {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
}

.aspect-icon {
  display: inline-block;
  position: relative;
  border: 1px solid var(--color-aspect-border);
  background: transparent;
}

.aspect-icon-square {
  width: 0.75rem;
  height: 0.75rem;
}

.aspect-icon-wide {
  width: 1.125rem;
  height: 0.625rem;
}

.tab-active .aspect-icon {
  border-color: var(--color-aspect-border-active);
}