/* Design tokens */
:root {
  color-scheme: light;
  --image-diff-background: #f4f6f8;
  --image-diff-surface: #ffffff;
  --image-diff-surface-muted: #f6f8fa;
  --image-diff-border: #d0d7de;
  --image-diff-border-strong: #8c959f;
  --image-diff-text: #1f2328;
  --image-diff-muted: #57606a;
  --image-diff-accent: #0969da;
  --image-diff-accent-hover: #0757b5;
  --image-diff-danger: #cf222e;
  --image-diff-success: #1a7f37;
  --image-diff-focus-ring: rgba(9, 105, 218, 0.25);
  --image-diff-control-hover: #eef1f4;
  --image-diff-control-disabled: #8c959f;
  --image-diff-drop-hover: #f0f7ff;
  --image-diff-notice-bg: #ddf4ff;
  --image-diff-notice-border: #b6e3ff;
  --image-diff-notice-text: #0550ae;
  --image-diff-success-bg: #dafbe1;
  --image-diff-checker-a: #ffffff;
  --image-diff-checker-b: #eaeef2;
  --image-diff-radius: 10px;
  --image-diff-card-radius: 9px;
  --image-diff-component-radius: 8px;
  --image-diff-control-radius: 7px;
  --image-diff-control-height: 36px;
  --image-diff-drop-height: 280px;
  --image-diff-comparison-height: 420px;
  --image-diff-canvas-height: 380px;
  --image-diff-mobile-drop-height: 220px;
  --image-diff-caption-bg: rgba(255, 255, 255, 0.92);
  --image-diff-canvas-border: rgba(31, 35, 40, 0.18);
  --image-diff-canvas-shadow: 0 4px 14px rgba(31, 35, 40, 0.14);
  --image-diff-shadow: 0 12px 30px rgba(31, 35, 40, 0.08);
}

/* Page foundation */
.image-diff-page,
.image-diff-page * {
  box-sizing: border-box;
}

body.image-diff-page {
  min-height: 100vh;
  margin: 0;
  color: var(--image-diff-text);
  background: var(--image-diff-background);
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

.image-diff-tool {
  width: min(1280px, calc(100% - 32px));
  margin: 0 auto;
  padding: 28px 0 48px;
}

:where(.image-diff-tool) .tool-header {
  margin-bottom: 18px;
}

:where(.image-diff-tool) .breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 12px;
  color: var(--image-diff-muted);
  font-size: 13px;
}

:where(.image-diff-tool) .breadcrumb a {
  color: var(--image-diff-accent);
  text-decoration: none;
}

:where(.image-diff-tool) .breadcrumb a:hover {
  text-decoration: underline;
}

:where(.image-diff-tool) .tool-header h1 {
  margin: 0 0 8px;
  font-size: clamp(25px, 3vw, 34px);
  line-height: 1.25;
}

:where(.image-diff-tool) .tool-header p {
  margin: 0;
  color: var(--image-diff-muted);
  font-size: 14px;
}

:where(.image-diff-tool) .privacy-notice {
  margin-bottom: 14px;
  padding: 12px 14px;
  border: 1px solid var(--image-diff-notice-border);
  border-radius: var(--image-diff-radius);
  color: var(--image-diff-notice-text);
  background: var(--image-diff-notice-bg);
  font-size: 14px;
}

/* Panels and headings */
:where(.image-diff-tool) .panel {
  margin-bottom: 14px;
  padding: 14px;
  border: 1px solid var(--image-diff-border);
  border-radius: var(--image-diff-radius);
  background: var(--image-diff-surface);
  box-shadow: var(--image-diff-shadow);
}

:where(.image-diff-tool) .panel-heading,
:where(.image-diff-tool) .source-heading,
:where(.image-diff-tool) .button-row {
  display: flex;
  align-items: center;
}

:where(.image-diff-tool) .comparison-toolbar,
:where(.image-diff-tool) .segmented-control,
:where(.image-diff-tool) .range-control,
:where(.image-diff-tool) .select-control {
  display: flex;
  align-items: center;
}

:where(.image-diff-tool) .panel-heading {
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 14px;
}

:where(.image-diff-tool) .panel-heading h2,
:where(.image-diff-tool) .source-heading h3 {
  margin: 0;
}

:where(.image-diff-tool) .panel-heading h2 {
  font-size: 18px;
}

:where(.image-diff-tool) .source-heading {
  justify-content: space-between;
  gap: 12px;
  padding: 12px;
  border-bottom: 1px solid var(--image-diff-border);
}

:where(.image-diff-tool) .source-heading h3 {
  font-size: 15px;
}

:where(.image-diff-tool) .button-row {
  flex-wrap: wrap;
  gap: 8px;
}

/* Form controls and buttons */
.image-diff-tool button,
.image-diff-tool .file-button,
.image-diff-tool select,
.image-diff-tool input {
  font: inherit;
}

.image-diff-tool button,
.image-diff-tool .file-button,
.image-diff-tool select {
  min-height: var(--image-diff-control-height);
  border: 1px solid var(--image-diff-border);
  border-radius: var(--image-diff-control-radius);
}

.image-diff-tool button,
.image-diff-tool .file-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 7px 12px;
  color: var(--image-diff-text);
  background: var(--image-diff-surface-muted);
  font-weight: 600;
  cursor: pointer;
}

.image-diff-tool button:hover:not(:disabled),
.image-diff-tool .file-button:hover {
  border-color: var(--image-diff-border-strong);
  background: var(--image-diff-control-hover);
}

.image-diff-tool button:focus-visible,
.image-diff-tool .file-button:focus-visible,
.image-diff-tool select:focus-visible,
.image-diff-tool input:focus-visible,
.image-diff-tool .drop-zone:focus-visible {
  outline: 3px solid var(--image-diff-focus-ring);
  outline-offset: 2px;
}

.image-diff-tool button:disabled {
  color: var(--image-diff-control-disabled);
  background: var(--image-diff-surface-muted);
  cursor: not-allowed;
}

:where(.image-diff-tool) .primary-button {
  border-color: var(--image-diff-accent);
  color: #ffffff;
  background: var(--image-diff-accent);
}

:where(.image-diff-tool) .primary-button:hover:not(:disabled) {
  border-color: var(--image-diff-accent-hover);
  background: var(--image-diff-accent-hover);
}

/* Image input cards */
:where(.image-diff-tool) .image-input-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

:where(.image-diff-tool) .image-source-card {
  overflow: hidden;
  min-width: 0;
  border: 1px solid var(--image-diff-border);
  border-radius: var(--image-diff-card-radius);
  background: var(--image-diff-surface);
}

:where(.image-diff-tool) .drop-zone {
  position: relative;
  display: grid;
  min-height: var(--image-diff-drop-height);
  padding: 12px;
  place-items: center;
  border: 2px dashed transparent;
  background: var(--image-diff-surface-muted);
  cursor: pointer;
  transition: border-color 0.15s ease, background 0.15s ease;
}

/* is-dragover is toggled by image-diff-viewer.js while a file is over the card. */
:where(.image-diff-tool) .drop-zone:hover,
:where(.image-diff-tool) .drop-zone.is-dragover {
  border-color: var(--image-diff-accent);
  background: var(--image-diff-drop-hover);
}

:where(.image-diff-tool) .drop-placeholder {
  display: flex;
  align-items: center;
  flex-direction: column;
  gap: 7px;
  color: var(--image-diff-muted);
  text-align: center;
}

:where(.image-diff-tool) .drop-placeholder strong {
  color: var(--image-diff-text);
}

:where(.image-diff-tool) .drop-placeholder span:last-child {
  font-size: 12px;
}

:where(.image-diff-tool) .drop-icon {
  display: grid;
  width: 42px;
  height: 42px;
  border: 1px solid var(--image-diff-border);
  border-radius: 50%;
  place-items: center;
  color: var(--image-diff-accent);
  background: var(--image-diff-surface);
  font-size: 26px;
  line-height: 1;
}

:where(.image-diff-tool) .source-preview {
  display: block;
  max-width: 100%;
  max-height: 360px;
  object-fit: contain;
}

/* has-image is the loaded-preview state managed by image-diff-viewer.js. */
:where(.image-diff-tool) .drop-zone.has-image .drop-placeholder {
  display: none;
}

:where(.image-diff-tool) .file-metadata {
  display: grid;
  grid-template-columns: minmax(0, 2fr) repeat(2, minmax(110px, 1fr));
  margin: 0;
  border-top: 1px solid var(--image-diff-border);
}

:where(.image-diff-tool) .file-metadata > div,
:where(.image-diff-tool) .stats-grid > div {
  min-width: 0;
}

:where(.image-diff-tool) .file-metadata > div {
  padding: 10px 12px;
}

:where(.image-diff-tool) .file-metadata > div + div,
:where(.image-diff-tool) .stats-grid > div + div {
  border-left: 1px solid var(--image-diff-border);
}

:where(.image-diff-tool) .file-metadata dt,
:where(.image-diff-tool) .stats-grid dt {
  margin-bottom: 3px;
  color: var(--image-diff-muted);
  font-size: 11px;
}

:where(.image-diff-tool) .file-metadata dd,
:where(.image-diff-tool) .stats-grid dd {
  margin: 0;
}

:where(.image-diff-tool) .file-metadata dd {
  overflow: hidden;
  font-size: 13px;
  font-weight: 600;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* Comparison controls */
:where(.image-diff-tool) .comparison-toolbar {
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 14px;
  padding: 10px;
  border: 1px solid var(--image-diff-border);
  border-radius: var(--image-diff-component-radius);
  background: var(--image-diff-surface-muted);
}

:where(.image-diff-tool) .mode-selector {
  margin: 0;
  padding: 0;
  border: 0;
}

:where(.image-diff-tool) .mode-selector legend {
  float: left;
  margin-right: 8px;
  padding: 8px 0;
  color: var(--image-diff-muted);
  font-size: 13px;
}

:where(.image-diff-tool) .segmented-control {
  gap: 0;
}

:where(.image-diff-tool) .segmented-control button {
  border-radius: 0;
}

:where(.image-diff-tool) .segmented-control button:first-child {
  border-radius: var(--image-diff-control-radius) 0 0 var(--image-diff-control-radius);
}

:where(.image-diff-tool) .segmented-control button:last-child {
  border-radius: 0 var(--image-diff-control-radius) var(--image-diff-control-radius) 0;
}

:where(.image-diff-tool) .segmented-control button + button {
  margin-left: -1px;
}

/* aria-pressed is synchronized with the active comparison mode by JavaScript. */
:where(.image-diff-tool) .segmented-control button[aria-pressed="true"] {
  z-index: 1;
  border-color: var(--image-diff-accent);
  color: #ffffff;
  background: var(--image-diff-accent);
}

:where(.image-diff-tool) .select-control,
:where(.image-diff-tool) .range-control {
  gap: 8px;
  color: var(--image-diff-muted);
  font-size: 13px;
}

:where(.image-diff-tool) .select-control select {
  min-width: 110px;
  padding: 6px 30px 6px 10px;
  color: var(--image-diff-text);
  background: var(--image-diff-surface);
}

:where(.image-diff-tool) .range-control {
  min-width: min(320px, 100%);
  flex: 1 1 270px;
}

:where(.image-diff-tool) .range-control input {
  min-width: 120px;
  flex: 1;
  accent-color: var(--image-diff-accent);
}

:where(.image-diff-tool) .range-control output {
  min-width: 36px;
  color: var(--image-diff-text);
  font-variant-numeric: tabular-nums;
  text-align: right;
}

/* Comparison display */
:where(.image-diff-tool) .comparison-stage {
  position: relative;
  overflow: hidden;
  min-height: var(--image-diff-comparison-height);
  border: 1px solid var(--image-diff-border);
  border-radius: var(--image-diff-component-radius);
  background:
    linear-gradient(45deg, var(--image-diff-checker-b) 25%, transparent 25%) 0 0 / 20px 20px,
    linear-gradient(45deg, transparent 75%, var(--image-diff-checker-b) 75%) 0 0 / 20px 20px,
    linear-gradient(45deg, transparent 75%, var(--image-diff-checker-b) 75%) 10px -10px / 20px 20px,
    linear-gradient(45deg, var(--image-diff-checker-b) 25%, var(--image-diff-checker-a) 25%) 10px -10px / 20px 20px;
}

/* is-empty is removed after both source images are available. */
:where(.image-diff-tool) .comparison-stage.is-empty {
  display: grid;
  place-items: center;
}

:where(.image-diff-tool) .empty-state {
  display: flex;
  align-items: center;
  flex-direction: column;
  gap: 6px;
  padding: 30px;
  color: var(--image-diff-muted);
  text-align: center;
}

:where(.image-diff-tool) .empty-state strong {
  color: var(--image-diff-text);
}

:where(.image-diff-tool) .side-view {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  min-height: var(--image-diff-comparison-height);
}

:where(.image-diff-tool) .side-view figure {
  min-width: 0;
  margin: 0;
}

:where(.image-diff-tool) .side-view figure + figure {
  border-left: 1px solid var(--image-diff-border);
}

:where(.image-diff-tool) .side-view figcaption {
  padding: 8px 12px;
  border-bottom: 1px solid var(--image-diff-border);
  background: var(--image-diff-caption-bg);
  font-size: 13px;
  font-weight: 600;
}

:where(.image-diff-tool) .single-view {
  min-height: var(--image-diff-comparison-height);
}

:where(.image-diff-tool) .canvas-scroll {
  overflow: auto;
  width: 100%;
  min-height: var(--image-diff-canvas-height);
  padding: 16px;
}

:where(.image-diff-tool) .single-view .canvas-scroll {
  display: grid;
  min-height: var(--image-diff-comparison-height);
  place-items: center;
}

.image-diff-tool canvas {
  display: block;
  width: auto;
  height: auto;
  max-width: 100%;
  border: 1px solid var(--image-diff-canvas-border);
  background: transparent;
  image-rendering: auto;
  box-shadow: var(--image-diff-canvas-shadow);
}

.image-diff-tool canvas.is-fixed-zoom {
  max-width: none;
}

/* Comparison statistics */
:where(.image-diff-tool) .stats-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  overflow: hidden;
  margin: 14px 0 0;
  border: 1px solid var(--image-diff-border);
  border-radius: var(--image-diff-component-radius);
}

:where(.image-diff-tool) .stats-grid > div {
  padding: 11px 12px;
  background: var(--image-diff-surface-muted);
}

:where(.image-diff-tool) .stats-grid dd {
  font-weight: 700;
  font-variant-numeric: tabular-nums;
}

/* Status messages */
:where(.image-diff-tool) .message {
  min-height: 20px;
  margin: 10px 0 0;
  color: var(--image-diff-muted);
  font-size: 13px;
}

:where(.image-diff-tool) .message.is-error {
  color: var(--image-diff-danger);
}

:where(.image-diff-tool) .message.is-success {
  color: var(--image-diff-success);
}

/* Utilities */
:where(.image-diff-tool) .visually-hidden {
  position: absolute !important;
  overflow: hidden;
  width: 1px;
  height: 1px;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
}

:where(.image-diff-page) [hidden] {
  display: none !important;
}

/* Responsive layout */
@media (max-width: 820px) {
  .image-diff-tool {
    width: min(100% - 20px, 1280px);
    padding-top: 18px;
  }

  :where(.image-diff-tool) .image-input-grid,
  :where(.image-diff-tool) .side-view,
  :where(.image-diff-tool) .stats-grid {
    grid-template-columns: 1fr;
  }

  :where(.image-diff-tool) .side-view figure + figure,
  :where(.image-diff-tool) .stats-grid > div + div,
  :where(.image-diff-tool) .file-metadata > div + div {
    border-left: 0;
  }

  :where(.image-diff-tool) .side-view figure + figure,
  :where(.image-diff-tool) .stats-grid > div + div {
    border-top: 1px solid var(--image-diff-border);
  }

  :where(.image-diff-tool) .file-metadata {
    grid-template-columns: 1fr;
  }

  :where(.image-diff-tool) .file-metadata > div + div {
    border-top: 1px solid var(--image-diff-border);
  }

  :where(.image-diff-tool) .panel-heading {
    align-items: flex-start;
    flex-direction: column;
  }

  :where(.image-diff-tool) .comparison-heading {
    align-items: center;
    flex-direction: row;
  }

  :where(.image-diff-tool) .mode-selector legend {
    float: none;
    margin: 0 0 6px;
    padding: 0;
  }

  :where(.image-diff-tool) .segmented-control {
    flex-wrap: wrap;
  }

  :where(.image-diff-tool) .range-control {
    align-items: flex-start;
    flex-direction: column;
  }

  :where(.image-diff-tool) .range-control input {
    width: 100%;
  }

  :where(.image-diff-tool) .drop-zone {
    min-height: var(--image-diff-mobile-drop-height);
  }
}