pdf.js/web/text_layer_builder.css

/* Copyright 2014 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

.textLayer {
  position: absolute;
  text-align: initial;
  inset: 0;
  overflow: hidden;
  opacity: 1;
  line-height: 1;
  text-size-adjust: none;
  forced-color-adjust: none;
  transform-origin: 0 0;
  z-index: 2;
  caret-color: CanvasText;

  &.highlighting {
    touch-action: none;
  }

  :is(span, br) {
    color: transparent;
    position: absolute;
    white-space: pre;
    cursor: text;
    transform-origin: 0% 0%;
  }

  /* Only necessary in Google Chrome, see issue 14205, and most unfortunately
   * the problem doesn't show up in "text" reference tests. */
  /*#if !MOZCENTRAL*/
  span.markedContent {
    top: 0;
    height: 0;
  }
  /*#endif*/

  .highlight {
    --highlight-bg-color: rgb(180 0 170 / 0.25);
    --highlight-selected-bg-color: rgb(0 100 0 / 0.25);
    --highlight-backdrop-filter: none;
    --highlight-selected-backdrop-filter: none;

    @media screen and (forced-colors: active) {
      --highlight-bg-color: transparent;
      --highlight-selected-bg-color: transparent;
      --highlight-backdrop-filter: var(--hcm-highlight-filter);
      --highlight-selected-backdrop-filter: var(
        --hcm-highlight-selected-filter
      );
    }

    margin: -1px;
    padding: 1px;
    background-color: var(--highlight-bg-color);
    backdrop-filter: var(--highlight-backdrop-filter);
    border-radius: 4px;

    &.appended {
      position: initial;
    }

    &.begin {
      border-radius: 4px 0 0 4px;
    }

    &.end {
      border-radius: 0 4px 4px 0;
    }

    &.middle {
      border-radius: 0;
    }

    &.selected {
      background-color: var(--highlight-selected-bg-color);
      backdrop-filter: var(--highlight-selected-backdrop-filter);
    }
  }

  ::selection {
    /*#if !MOZCENTRAL*/
    background: rgba(0 0 255 / 0.25);
    /*#endif*/
    /* stylelint-disable-next-line declaration-block-no-duplicate-properties */
    background: color-mix(in srgb, AccentColor, transparent 75%);
  }

  /* Avoids https://github.com/mozilla/pdf.js/issues/13840 in Chrome */
  /*#if !MOZCENTRAL*/
  br::selection {
    background: transparent;
  }
  /*#endif*/

  .endOfContent {
    display: block;
    position: absolute;
    inset: 100% 0 0;
    z-index: -1;
    cursor: default;
    user-select: none;

    &.active {
      top: 0;
    }
  }
}