"snap to fit" for preview slides does not work in Firefox

[thescientist13]

Type of Change

• New Feature Request
• Documentation
• Improvement / Suggestion
• Bug
• Other (please clarify below)

Summary

Comparing the starter template in FF vs Chrome, it looks like the preview slides on the left are all big and out of perspective.

Chrome

FF

Details

Likely has to do with the code inside the <iframe> we use.
https://github.com/thescientist13/greenwood-starter-presentation/blob/master/src/components/slide-list.js#L83

slideLoaded(slide) {
  const frame = this.shadowRoot.getElementById(`slide_${slide.id}`);
  const style = document.createElement('style');
  
  style.textContent = `
    body {
      zoom: .4;
    } 
  `;
  
  frame.contentDocument.head.appendChild(style);
}