chrome/browser/resources/extensions/options_dialog.html

<style>
  #icon {
    height: 32px;
    margin-inline-end: 10px;
    width: 32px;
  }

  #icon-and-name-wrapper {
    align-items: center;
    display: flex;
  }

  ExtensionOptions {
    display: block;
    height: 100%;
    overflow: hidden;
  }

  cr-dialog::part(dialog) {
    /* CSS variables are set by the JS. */
    height: var(--dialog-height);
    opacity: var(--dialog-opacity, 0);
    /* When loading, it's possible for an size update to follow after the
       initial size update. The debounce time on size updates is 50ms.
       A 100ms delay for the opacity transition will allow two updates to
       occur without showing the dialog resizing to the user. */
    transition: opacity 100ms ease 100ms;
    width: var(--dialog-width);
  }

  cr-dialog::part(wrapper) {
    height: 100%;
    max-height: initial;
    overflow: hidden;
  }

  cr-dialog #body {
    height: 100%;
    padding: 0;
  }

  cr-dialog {
    --cr-dialog-body-border-bottom: none;
    --cr-dialog-body-border-top: none;
    --scroll-border: none;
  }

  cr-dialog::part(body-container) {
    height: 100%;
    min-height: initial;
  }
</style>

<cr-dialog id="dialog" close-text="$i18n{close}"
    on-close="onClose_" show-close-button>
  <div slot="title">
    <div id="icon-and-name-wrapper">
      <img id="icon" src="[[data_.iconUrl]]" alt="">
      <span>[[data_.name]]</span>
    </div>
  </div>
  <div slot="body" id="body">
  </div>
</cr-dialog>