discourse/app/assets/stylesheets/common/base/history.scss

// styles that apply to the popup that appears when you show the edit history of a post

.modal.history-modal {
  #revision-numbers {
    display: inline-block;
    min-width: 96px;
    text-align: center;
  }

  #revision {
    overflow: auto;
  }

  #revision-controls {
    display: inline-block;
    margin-bottom: 5px;
  }

  .revision-content {
    width: 47.5%;
    float: left;
    &:nth-of-type(2) {
      margin-left: 5%;
    }
  }

  #revision-details {
    padding: 5px;
    margin-top: 10px;
    border-bottom: 3px solid $primary-low;     
  }

  #revisions .row:first-of-type {
    margin-top: 10px;
  }
  ins, .diff-ins {
    code, img {
      border: 2px solid $success;
    }
    img {
      opacity: .75;
      filter: alpha(opacity=75);
    }
    a {
      color: $success;
      text-decoration: none;
    }
  }
  img.diff-ins, code.diff-ins {
    border: 2px solid $success;
  }
  img.diff-ins {
    opacity: .75;
    filter: alpha(opacity=75);
  }
  .diff-ins {
    color: dark-light-choose($primary, $secondary);
    background: $success-low;
  }
  ins {
    color: $success;
    background: $success-low;
  }
  del, .diff-del {
    code, img {
      border: 2px solid $danger;
    }
    img {
      opacity: .5;
      filter: alpha(opacity=50);
    }
    a {
      color: $danger;
      text-decoration: none;
    }
  }
  img.diff-del, code.diff-del {
    border: 2px solid $danger;
  }
  img.diff-del {
    opacity: .5;
    filter: alpha(opacity=50);
  }
  .diff-del {
    background: $danger-low;
  }
  del {
    color: $danger;
    background: $danger-low;
  }
  span.date {
    font-weight: bold;
  }
  span.edit-reason {
    background-color: lighten($highlight, 23%);
    padding: 3px 5px 5px 5px;
  }
  .d-icon-ban {
    color: #f00;
  }
  .hidden-revision-either {
    opacity: .5;
  }
  .hidden-revision-previous .row {
    div:nth-of-type(1), td:nth-of-type(1) {
      opacity: .5;
    }
  }
  .hidden-revision-current .row {
    div:nth-of-type(2), td:nth-of-type(2) {
      opacity: .5;
    }
  }
}