old_contents: 
  let obj = !localStorage ? {id: 'theme-light', type: 'light'} : JSON.parse(localStorage.getItem("ui-theme"));
  if ( !obj ) {
      if ( window.matchMedia && window.matchMedia('(prefers-color-scheme: dark)').matches ) {
          obj = {id: 'theme-dark', type: 'dark'};
          localStorage && localStorage.setItem("ui-theme", JSON.stringify(obj));
      }
  }
  
  document.body.classList.add(`theme-type-${obj.type}`);
  
new_contents: 
  let obj = !localStorage ? {id: 'theme-light', type: 'light'} : JSON.parse(localStorage.getItem("ui-theme"));
  if ( !obj ) {
      obj = window.matchMedia && window.matchMedia('(prefers-color-scheme: dark)').matches ?
                  {id: 'theme-dark', type: 'dark'} : {id: 'theme-light', type: 'light'};
      localStorage && localStorage.setItem("ui-theme", JSON.stringify(obj));
  }
  
  document.body.classList.add(`theme-type-${obj.type}`);
  
subject: fix bug 55103