forgejo/web_src/less/features/imagediff.less

.image-diff-container {
  text-align: center;
  padding: 30px 0;

  img {
    border: 1px solid var(--color-primary-light-7);
    background: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAoAAAAKCAYAAACNMs+9AAAAG0lEQVQYlWN4+vTpf3SMDTAMBYXYBLFpHgoKAeiOf0SGE9kbAAAAAElFTkSuQmCC) right bottom var(--color-primary-light-7);
  }

  .before-container {
    border: 1px solid var(--color-red);
    display: block;
  }

  .after-container {
    border: 1px solid var(--color-green);
    display: block;
  }

  .diff-side-by-side {
    .side {
      display: inline-block;
      line-height: 0;
      vertical-align: top;

      .side-header {
        font-weight: bold;
      }
    }
  }

  .diff-swipe {
    margin: auto;

    .swipe-frame {
      position: absolute;

      .before-container {
        position: absolute;
      }

      .swipe-container {
        position: absolute;
        right: 0;
        display: block;
        border-left: 2px solid var(--color-secondary-dark-8);
        height: 100%;
        overflow: hidden;

        .after-container {
          position: absolute;
          right: 0;
        }
      }

      .swipe-bar {
        z-index: 100;
        position: absolute;
        height: 100%;
        top: 0;
        left: 0;

        .handle {
          background: var(--color-secondary-dark-8);
          left: -5px;
          height: 12px;
          width: 12px;
          position: absolute;
          transform: rotate(45deg);
          box-sizing: border-box;
          display: flex;
          justify-content: center;
          align-items: center;
          cursor: pointer;
        }

        .top-handle {
          top: -12px;
        }

        .bottom-handle {
          bottom: -14px;
        }
      }
    }
  }

  .diff-overlay {
    margin: 0 auto;

    .overlay-frame {
      margin: 0 auto;
      position: relative;
    }

    .before-container,
    .after-container {
      position: absolute;
    }

    input {
      width: 300px;
    }
  }
}