How to stop css repeatition

hi @artf here is my code of Export-template i make it editable

define(function() {
  const juice = require('juice');
  return (opt = {}) => {
    let editor = opt.editor;
    let codeViewer = editor && editor.CodeManager.getViewer('CodeMirror').clone();
    let btnImp = document.createElement("button");
    let container = document.createElement("div");
      var cmdm = editor.Commands;
    let pfx = opt.pfx || '';
    const juiceOpts = opt.juiceOpts || {};
    // Init import button
    btnImp.innerHTML = opt.modalBtnImport;
    btnImp.className = pfx + 'btn-prim ' + pfx + 'btn-import';
    btnImp.onclick = () => {
      let code = codeViewer.editor.getValue();
      editor.DomComponents.getWrapper().set('content', '');
      editor.setComponents(code);
      editor.Modal.close();
    };
    // Init code viewer
    codeViewer.set({
      codeName: 'htmlmixed',
      theme: opt.codeViewerTheme,
      readOnly: 0
    });

    // Set the command which could be used outside
    cmdm.add(opt.cmdInlineHtml, {
      run(editor, sender, opts = {}) {
        const tmpl = editor.getHtml() + `<style>${editor.getCss()}</style>`;
        return juice(tmpl, opts);
      }
    })

    return {
      run(editor, sender) {
        let md = editor.Modal;
        let modalContent = md.getContentEl();
        let viewer = codeViewer.editor;
        md.setTitle(opt.modalTitleImport);
        // Init code viewer if not yet instantiated
        if(!viewer){
          let txtarea = document.createElement('textarea');
          if(opt.modalLabelImport){
            let labelEl = document.createElement('div');
            labelEl.className = pfx + 'import-label';
            labelEl.innerHTML = opt.modalLabelImport;
            container.appendChild(labelEl);
          }
          container.appendChild(txtarea);
          container.appendChild(btnImp);
          codeViewer.init(txtarea);
          viewer = codeViewer.editor;
          viewer.setOption('lineWrapping', 1);
        }
        md.setContent(container);
        const tmpl = editor.getHtml() + `<style>${editor.getCss()}</style>`;
        codeViewer.setContent(opt.inlineCss ? juice(tmpl, juiceOpts) : tmpl);
        md.open();
        viewer.refresh();
        sender && sender.set('active', 0);
      },
    }
  };
});

Also, i add a media-query to display in view code with this

editor.setComponents(mycss)

when i update something form this button it'll work fine but i am using it in my rails app by including minified version . and when update something in rails all media-query css got repeated Can you please suggest me something to handle this.???

Thanks