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

<picture>
  <source media="(prefers-color-scheme: dark)" srcset="${this.darkImagePath}">
  <img id="product-logo" srcset="${this.imagePath}" alt="">
</picture>
<div id="heading">${this.heading}</div>
<div id="body">${this.body}</div>