platform/packages/theme/styles/_text-editor.scss

.ProseMirror {
  outline: none;

  &.text-editor-view {
    font: inherit;
    line-height: 150%;
  }
}

.text-editor-view {
  // overflow-y: auto;
  color: var(--theme-text-primary-color);

  .suggestion {
    display: inline-flex;
    padding: 0 .25rem;
    color: var(--theme-link-color);
    background-color: var(--theme-mention-bg-color);
    border-radius: .25rem;
  }

  .title,
  h1,
  h2,
  h3,
  b {
    font-weight: 600;
  }

  h1,
  h2,
  h3 {
    &:first-child {
      margin-top: 0;
    }
  }

  .title {
    font-size: 2.25rem;
    margin-top: 3.75rem;
    margin-bottom: 0.25rem;
  }

  h1 {
    font-size: 1.75rem;
    margin-top: 2.75rem;
    margin-bottom: 0.25rem;
  }

  h2 {
    font-size: 1.375rem;
    margin-top: 2.25rem;
    margin-bottom: 0.25rem;
  }

  h3 {
    font-size: 1.125rem;
    margin-top: 1.5rem;
    margin-bottom: 0.25rem;
  }

  p {
    margin-block-start: 0.5rem;
  }

  >*+* {
    margin-top: 0.5rem;
    margin-bottom: 0;
  }

  ul,
  ol {
    margin-right: .25rem;
    margin-left: .75rem;
    padding: 0;
  }

  li {
    margin-left: 0.75rem;
    padding-left: 0.375rem;
  }

  li p {
    margin: 0;
  }

  ul[data-type="todoList"] {
    list-style: none;
    margin: 0;
    padding: 0;

    li {
      margin: 0;
      padding: 0;
    }
  }

  ol ol { list-style: lower-alpha; }
  ol ol ol { list-style: lower-roman; }
  ol ol ol ol { list-style: decimal; }
  ol ol ol ol ol { list-style: lower-alpha; }
  ol ol ol ol ol ol { list-style: lower-roman; }
  ol ol ol ol ol ol ol { list-style: decimal; }

  blockquote {
    margin-inline: 1px 0;
    padding-left: 1.5em;
    padding-right: 1.5em;
    font-style: italic;
    position: relative;

    border-left: 3px solid var(--theme-text-primary-color);
  }

  /* Placeholder (at the top) */
  p.is-editor-empty:first-child::before {
    content: attr(data-placeholder);
    float: left;
    color: var(--theme-text-placeholder-color);
    pointer-events: none;
    height: 0;
  }

  &.text-editor-view_compact {
    min-height: 0;
    height: 100%;
  }

  &.text-editor-view_full-height {
    min-height: 0;
    max-height: 100%;
    height: auto;
  }

  &:focus-within p.is-editor-empty:first-child::before {
    color: var(--theme-trans-color);
  }

  &::-webkit-scrollbar-thumb {
    background-color: var(--scrollbar-bar-color);
  }

  &::-webkit-scrollbar-thumb:hover {
    background-color: var(--scrollbar-bar-hover);
  }

  &::-webkit-scrollbar-corner {
    background-color: var(--scrollbar-bar-color);
  }

  &::-webkit-scrollbar-track {
    margin: 0;
  }

  /* Give a remote user a caret */
  .collaboration-cursor__caret {
    border-left: 1px solid #0d0d0d;
    border-right: 1px solid #0d0d0d;
    margin-left: -1px;
    margin-right: -1px;
    pointer-events: none;
    position: relative;
    word-break: normal;
  }

  /* Render the username above the caret */
  .collaboration-cursor__label {
    border-radius: 3px 3px 3px 0;
    color: #0d0d0d;
    font-size: 12px;
    font-style: normal;
    font-weight: 600;
    left: -1px;
    line-height: normal;
    padding: 0.1rem 0.3rem;
    position: absolute;
    top: -1.4em;
    user-select: none;
    white-space: nowrap;
  }

  cmark {
    border-top: 1px solid lightblue;
    border-bottom: 1px solid lightblue;
    border-radius: 2px;
  }

  span.insertion {
    border-top: 1px solid lightblue;
    border-bottom: 1px solid lightblue;
    border-radius: 2px;
  }

  span.deletion {
    text-decoration: line-through;
  }
}

.text-editor-image-container {
  display: flex;
  flex-direction: row;

  &[data-align="center"] {
    justify-content: center;
  }

  &[data-align="left"] {
    justify-content: left;
  }

  &[data-align="right"] {
    justify-content: right;
  }
}

.text-editor-image-container {
  img {
    max-width: 100%;
  }
}

.text-editor-image {
  cursor: pointer;
  object-fit: contain;
}

.ProseMirror-selectednode {
  img {
    box-shadow: 0 0 0 2px var(--text-editor-selected-node-color);
    border-radius: 0.125rem;
  }
}

.reference {
  &:hover,
  &.ProseMirror-selectednode {
    background-color: var(--theme-mention-focused-bg-color);
  }
}

.text-editor-highlighted-node-warning {
  background-color: var(--text-editor-highlighted-node-warning-background-color);
  border-bottom: 0.0625rem solid var(--text-editor-highlighted-node-warning-border-color);

  &.text-editor-highlighted-node-selected, &:hover {
    background-color: var(--text-editor-highlighted-node-warning-active-background-color);
  }
}

.text-editor-highlighted-node-delete {
  background-color: var(--text-editor-highlighted-node-delete-background-color);
  color: var(--text-editor-highlighted-node-delete-font-color);
  text-decoration: line-through;
}

.text-editor-highlighted-node-add {
  background-color: var(--text-editor-highlighted-node-add-background-color);
  color: var(--text-editor-highlighted-node-add-font-color)
}

.text-editor-popup {
  background-color: var(--theme-comp-header-color);
  border-radius: 0.5rem;
  box-shadow: var(--theme-popup-shadow);
  z-index: 1;
}

.text-editor-lint-icon {
  display: inline-block;
  position: absolute;
  right: 2px;
  cursor: pointer;
  border-radius: 100px;
  // background: #f22;
  color: white;
  font-family: times, georgia, serif;
  font-size: 15px;
  font-weight: bold;
  width: 0.7em;
  height: 0.7em;
  text-align: center;
  padding-left: 0.5px;
  line-height: 1.1em;

  &.add {
    background: lightblue;
  }

  &.delete {
    background: orange;
  }
}