chromium/chrome/browser/resources/chromeos/borealis_installer/error_dialog.html

<style>
  cr-dialog {
    --cr-dialog-width: 440px;
    border-radius: 24px;
  }

  cr-dialog [slot=title] {
    color: var(--cros-text-color-primary);
    font: var(--cros-title-2-font);
    padding: 24px 24px 16px;
  }

  cr-dialog [slot=body] {
    color: var(--cros-text-color-secondary);
    font: var(--cros-body-1-font);
    padding: 0 24px;
  }

  cr-dialog [slot=button-container] {
    font: var(--cros-button-1-font);
    padding: 49px 24px 24px;
  }

  .action-button {
    border-radius: 24px;
  }

  .cancel-button {
    border-radius: 24px;
  }

  .error-icon {
    --iron-icon-fill-color: var(--cros-icon-color-alert);
    --iron-icon-height: 24px;
    --iron-icon-width: 24px;
    padding-bottom: 10px
  }
</style>

<cr-dialog id="dialog">
  <div slot="title">
    <div id="error-icon">
      <iron-icon class="error-icon" icon="borealis_installer:error"></iron-icon>
    </div>
    $i18n{errorTitle}
  </div>
  <div slot="body">[[getMessage(behaviour)]]</div>
  <div id="link" slot="body" hidden="[[!shouldShowLink(behaviour)]]">
    <a href="[[getLink(behaviour)]]" target="_blank">$i18n{learnMore}</a>
  </div>
  <div slot="button-container">
    <cr-button
        id="cancel"
        class="cancel-button"
        on-click="onCancelButtonClicked">
      $i18n{cancel}
    </cr-button>
    <cr-button id="retry"
        class="action-button"
        on-click="onRetryButtonClicked"
        hidden="[[!shouldShowRetryButton(behaviour)]]">
      $i18n{retry}
    </cr-button>
    <cr-button
        id="storage"
        class="action-button"
        on-click="onStorageButtonClicked"
        hidden="[[!shouldShowStorageButton(behaviour)]]">
      $i18n{storage}
    </cr-button>
  </div>
</cr-dialog>