How to direct a bootstrap library to a html DIV

here is a small example of an html, what you happen is that I have a page which presents its own design (styles.css), and I am implementing a design for a multiselect, which requires bootstrap-multiselect.css and bootstrap-3.3.2.min.css .... so when I add this html code it distorts the design of what I'm adding, but I was thinking about implementing a DIV in the multiselect with an ID called "drawing", and What I want is that those bootstrap libraries that I present only affect that DIV

<br/><br/>
<label>DNI</label>
<input type="text" id="dni"> 

<div id="dibujo">
</br></br>
<select  id="tecnologia" name="tecnologia[]" multiple="multiple" size="5">
 <option value="2g">2G</option> 
  <option value="3g">3G</option> 
 <option value="4g">4G</option> 
 <option value="tdd">TDD</option>
  </select>

 <script type="text/javascript">
$(function() {
    $('#tecnologia').multiselect({

    buttonText: function(options, select){
      console.log(select[0].length);
      if (options.length===0) {
        return 'sin Seleccion';
      }
      if (options.length===select[0].length) {
        return 'todos ('+select[0].length+')';
      }
      else if(options.length>=1){
        return options.length+' seleccionados';
      }else{

        var labels=[];
        console.log(options);
        options.each(function(){
          labels.push($(this).val());
        });
        return labels.join(', ')+'';
      }

    }
  });
});

this is a bootstrap code ... as you can see it is a very extensive code