:root {
    --panel-border:  color-mix(in srgb, var(--warn) 42%, transparent);
    --diff-rule:     color-mix(in srgb, var(--text-muted) 22%, var(--bg));
  }

  :root.dark {
    --panel-border:  color-mix(in srgb, var(--warn) 34%, transparent);
    --diff-rule:     color-mix(in srgb, var(--text-muted) 32%, var(--bg));
    --diff-del-panel: rgba(255, 43, 43, 0.16);
    --diff-add-panel: rgba(126, 255, 43, 0.11);
  }

  body.diff-scene {
    height: auto;
    overflow: visible;
    padding: clamp(8px, 2vw, 20px);
    font-size: clamp(7.5px, 1.45vw, 13px);
  }

  .diff-stage {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
  }

  .diff-panel {
    position: relative;
    overflow: hidden;
    border: 1.5px solid var(--panel-border);
    border-radius: 8px;
    padding: 1.25em 0.75em;
    background: var(--bg);
    transition: border-color 0.3s ease, background-color 0.3s ease;
  }

  .diff-panel::after {
    content: "";
    position: absolute;
    inset: 0 0 0 auto;
    width: 2.5em;
    background: linear-gradient(to right, transparent, var(--bg) 85%);
    pointer-events: none;
  }

  .diff-panel .tool-header {
    margin: 0 0 1em;
    padding-bottom: 0;
    font-size: inherit;
    gap: 0.5em;
  }
  .diff-panel .tool-header-sub {
    font-size: inherit;
  }
  .diff-panel .tool-header-arrow {
    flex: none;
  }

  .diff-panel .diff-body {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    border-radius: 0;
  }
  .diff-panel .diff-line {
    width: max-content;
    max-width: 100%;
    padding: 0 0.2em 0 0;
    font-size: inherit;
    border-radius: 0;
  }
  .diff-panel .diff-ln {
    width: 2.2em;
    padding-right: 0.6em;
    font-size: inherit;
    opacity: 1;
    color: var(--code-line);
  }
  .diff-panel .diff-sign {
    width: 1ch;
    margin-right: 1ch;
  }
  .diff-panel:not(.diff-plain) .diff-line-del .diff-ln,
  .diff-panel:not(.diff-plain) .diff-line-add .diff-ln {
    color: color-mix(in srgb, var(--code-plain) 75%, var(--bg));
  }

  :root.dark .diff-panel:not(.diff-plain) .diff-line-del { background: var(--diff-del-panel); }
  :root.dark .diff-panel:not(.diff-plain) .diff-line-add { background: var(--diff-add-panel); }

  .diff-hidden {
    padding-left: 0.4em;
    color: var(--text-muted);
    white-space: pre;
    line-height: 1.75;
    transition: color 0.3s ease;
  }
  .diff-gap {
    align-self: stretch;
    height: 1px;
    margin: 0.85em 0;
    background-color: var(--diff-rule);
  }

  .diff-plain .diff-line-del,
  .diff-plain .diff-line-add {
    background: none;
  }
  .diff-plain .diff-line-del .diff-code { color: var(--diff-del); }
  .diff-plain .diff-line-add .diff-code {
    color: color-mix(in srgb, var(--diff-add) 82%, var(--text));
  }
  :root.dark .diff-plain .diff-line-add .diff-code { color: var(--diff-add); }
  .diff-plain .diff-ln,
  .diff-plain .diff-hidden {
    color: var(--text);
  }
  .diff-plain .diff-gap {
    height: 4px;
    margin: 0.7em 0;
    background-color: transparent;
    border-top: 1px solid var(--text);
    border-bottom: 1px solid var(--text);
  }

  .diff-compare {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: clamp(8px, 1.2vw, 16px);
  }
  .diff-column {
    display: flex;
    min-width: 0;
    flex-direction: column;
    margin: 0;
  }
  .diff-column .diff-panel {
    flex: 1;
  }
  .diff-label {
    margin-bottom: clamp(8px, 1.2vw, 16px);
    font-family: Inter, ui-sans-serif, system-ui, sans-serif;
    line-height: 1.2;
    text-align: center;
  }
  .diff-label-name {
    display: block;
    color: var(--text);
    font-size: 1.9em;
    font-weight: 700;
    letter-spacing: -0.02em;
    transition: color 0.3s ease;
  }
  .diff-label-note {
    display: block;
    margin-top: 0.5em;
    color: var(--text-muted);
    font-size: 1em;
    transition: color 0.3s ease;
  }

  .diff-panel .tool-question {
    margin: 1.4em 0 0.9em;
    font-size: inherit;
  }
  .diff-panel .tool-body {
    display: flex;
    flex-direction: column;
    align-items: stretch;
    width: fit-content;
    min-width: 280px;
    max-width: 100%;
    font-size: inherit;
  }
  .diff-panel .tool-opt {
    cursor: default;
  }
  .diff-panel .tool-opt:not(.selected):hover {
    background: none;
  }

  .diff-plain {
    --panel-border: color-mix(in srgb, var(--accent-purple) 42%, transparent);
  }
  :root.dark .diff-plain {
    --panel-border: color-mix(in srgb, var(--accent-purple) 34%, transparent);
  }
  .diff-plain .tool-q {
    color: var(--accent-purple);
  }
  .diff-plain .tool-opt.selected {
    background: none;
    color: var(--accent-purple);
  }
  .diff-plain .tool-opt.selected .tool-opt-bullet,
  .diff-plain .tool-opt.selected .tool-opt-num {
    color: var(--accent-purple);
  }

  @media (max-width: 40rem) {
    .diff-label-note {
      display: none;
    }
  }