title_body: Calibre ebook viewer - Apply User Stylesheet to Full Screen Mode How do I apply styles to full screen mode only via the User Stylesheet?
  Specifically, I would like to adjust the body style during full screen mode to adjust margin-left.
  
  I would like to do this through the User Stylesheet so that changes are applied automatically and I don't have to edit them manually every time I open full screen view.
  
  Currently, I can edit the body tag, but this is applied whether in full screen mode or not.
  
  I feel like there should be some parent element for full screen view so a selector could be used such as fullscreen &gt; body.
  
  Ideas?
  
  Update: It looks like the preferences for full screen options, which are limited to max width and max text height, uses javascript to manage the styling. 
  
  Any ideas for injecting a parent element that wraps all CSS while in_fullscreen_mode = True in documentview.py?
upvoted_answer: Paste the following in the 'User stylesheet', click ok. Then go to 'Theming' and save the style with whatever name you like. The e-book will display nicely in any screen mode and there are a couple of neat little extras you won't see with other user themes. As with all CSS it can be further altered and tweaked to suit.
  
  html {
      background: #e6e9e9;
      background-image: linear-gradient(270deg, rgb(230, 233, 233) 0%, rgb(216, 221, 221) 100%);
      -webkit-font-smoothing: antialiased;
  }
  
  body {
      background: #1f2326;
      box-shadow: 0 0 2px rgb(225, 225, 225);
      color: #d4d4d4;
      font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
      font-size: 16px;
      line-height: 1.5;
      margin: 0 auto;
      max-width: 800px;
      padding: 2em 2em 4em;
  }
  
  h1, h2, h3, h4, h5, h6 {
      color: #e4e7e7;
      font-weight: 600;
      line-height: 1.3;
  }
  
  h2 {
      margin-top: 1.3em;
  }
  
  a {
      color: #2196f3;
  }
  
  b, strong {
      font-weight: 600;
  }
  
  samp {
      display: none;
  }
  
  img {
      animation: colorize 2s cubic-bezier(0, 0, .78, .36) 1;
      background: transparent;
      border: 10px solid rgb(145, 143, 140);
      border-radius: 4px;
      display: block;
      margin: 1.3em auto;
      max-width: 95%;
  }
  
  @keyframes colorize {
      0% {
          -webkit-filter: grayscale(100%);
          filter: grayscale(100%);
      }
      100% {
          -webkit-filter: grayscale(0%);
          filter: grayscale(0%);
      }
  }