chrome/browser/resources/side_panel/shared/sp_heading.html

<style include="cr-hidden-style sp-shared-style">
  :host {
    align-items: center;
    display: flex;
    flex-shrink: 0;
    gap: 4px;
    height: 36px;
  }

  :host([compact]) {
    height: 28px;
  }

  :host-context([chrome-refresh-2023]):host([compact]) {
    height: 36px;
  }

  #backButton,
  ::slotted(cr-icon-button[slot=buttons]) {
    --cr-icon-button-icon-size: 16px;
    --cr-icon-button-size: 24px;
  }

  #backButton {
    margin: 0 -4px;
  }

  ::slotted(cr-icon-button[slot=buttons]) {
    margin: 0;
  }

  :host-context([chrome-refresh-2023]) #backButton {
    --cr-icon-button-fill-color: var(--cr-primary-text-color);
  }

  :host-context([chrome-refresh-2023]) ::slotted(cr-icon-button[slot=buttons]) {
    --cr-icon-button-fill-color: var(--cr-secondary-text-color);
  }

  ::slotted([slot=heading]:is(h1, h2, h3, h4, h5, h6)) {
    color: var(--cr-primary-text-color);
    flex: 1;
    font-size: 13px;
    font-weight: 500;
    line-height: 20px;
    margin: 0;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }

  :host-context([chrome-refresh-2023])
      ::slotted([slot=heading]:is(h1, h2, h3, h4, h5, h6)) {
    font-size: 14px;
  }

  :host([compact]) ::slotted([slot=heading]:is(h1, h2, h3, h4, h5, h6)) {
    color: var(--cr-secondary-text-color);
    font-size: 11px;
    font-weight: 600;
    line-height: 16px;
    text-transform: uppercase;
  }

  :host-context([chrome-refresh-2023]):host([compact])
      ::slotted([slot=heading]:is(h1, h2, h3, h4, h5, h6)) {
    color: var(--cr-primary-text-color);
    font-size: 14px;
    font-weight: 500;
    line-height: 20px;
    text-transform: none;
  }

  ::slotted([slot=metadata]) {
    color: var(--cr-secondary-text-color);
    flex-shrink: 0;
    font-size: 13px;
    font-weight: 400;
    line-height: 20px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }

  :host-context([chrome-refresh-2023]) ::slotted([slot=metadata]) {
    font-size: 11px;
    line-height: 16px;
  }
</style>

<cr-icon-button id="backButton" iron-icon="cr:arrow-back"
    hidden$="[[hideBackButton]]" disabled$="[[disableBackButton]]"
    on-click="onBackButtonClick_" aria-label$="[[backButtonAriaLabel]]"
    title$="[[backButtonTitle]]">
</cr-icon-button>

<slot name="heading"></slot>
<slot name="metadata"></slot>
<div class="sp-icon-buttons-row"><slot name="buttons"></slot></div>