chrome/browser/resources/side_panel/customize_chrome/app.html

<style include="sp-shared-style">
  :host-context([chrome-refresh-2023]):host {
    display: block;
    padding: var(--sp-body-padding) 0;
  }

  sp-heading {
    margin: 8px 16px;
  }

  .card-separator {
    background-color: var(--google-grey-300);
    border: none;
    height: 2px;
    margin: 0;
    width: 100%;
  }

  @media (prefers-color-scheme: dark) {
    .card-separator {
      background-color: var(--google-grey-700);
    }
  }

  :host-context([chrome-refresh-2023]) .card-separator {
    background: transparent;
    height: 8px;
  }

  :host-context([chrome-refresh-2023]) .sp-card {
    max-width: calc(320px - 2 * var(--sp-body-padding));
  }

  customize-chrome-appearance {
    margin-bottom: 16px;
  }

  customize-chrome-appearance,
  customize-chrome-shortcuts,
  customize-chrome-cards,
  customize-chrome-categories,
  customize-chrome-themes,
  customize-chrome-chrome-colors {
    display: block;
    max-width: 320px;
    width: 100%;
  }
</style>
<iron-pages selected="[[page_]]" attr-for-selected="page-name">
  <div page-name="overview" id="overviewPage">
    <div id="appearance" class="section sp-card">
      <sp-heading hide-back-button>
        <h2 slot="heading">$i18n{appearanceHeader}</h2>
      </sp-heading>
      <customize-chrome-appearance on-edit-theme-click="onEditThemeClick_"
        id="appearanceElement">
      </customize-chrome-appearance>
    </div>
    <hr class="card-separator">
    <div id="shortcuts" class="section sp-card">
      <sp-heading hide-back-button>
        <h2 slot="heading">$i18n{shortcutsHeader}</h2>
      </sp-heading>
      <customize-chrome-shortcuts></customize-chrome-shortcuts>
    </div>
    <template is="dom-if" if="[[modulesEnabled_]]">
      <hr class="card-separator">
      <div id="modules" class="section sp-card">
        <sp-heading hide-back-button>
          <h2 slot="heading">$i18n{cardsHeader}</h2>
        </sp-heading>
        <customize-chrome-cards></customize-chrome-cards>
      </div>
    </template>
  </div>
  <customize-chrome-categories on-back-click="onBackClick_"
      on-collection-select="onCollectionSelect_" page-name="categories"
      id="categoriesPage" on-local-image-upload="onLocalImageUpload_"
      on-chrome-colors-select="onChromeColorsSelect_">
  </customize-chrome-categories>
  <customize-chrome-themes on-back-click="onBackClick_"
      page-name="themes" id="themesPage"
      selected-collection="[[selectedCollection_]]">
  </customize-chrome-themes>
  <customize-chrome-chrome-colors on-back-click="onBackClick_"
      page-name="chrome-colors" id="chromeColorsPage">
  </customize-chrome-chrome-colors>
</iron-pages>