Wanna Make search-bar responsive

I have wordpress blog and I need to add search-bar in headerI want to make my search-bar responsive how can i do that? see the code please

/*Expandable Search CSS*/

.container-2{
  width: 300px;
  vertical-align: middle;
  white-space: nowrap;
  position: relative;
}

.container-2 input#search{
  width: 1px;
  height: 50px;
  background: #2b303b;
  border: none;
  font-size: 10pt;
   color: #262626;
  padding-left: 35px;
  -webkit-border-radius: 5px;
  -moz-border-radius: 5px;
  border-radius: 5px;
  color: #fff;
 
  -webkit-transition: width .55s ease;
  -moz-transition: width .55s ease;
  -ms-transition: width .55s ease;
  -o-transition: width .55s ease;
  transition: width .55s ease;
  margin-bottom: -60px;
  float: right;
 
}

.container-2 input#search::-webkit-input-placeholder {
   color: #65737e;
}
 
.container-2 input#search:-moz-placeholder { /* Firefox 18- */
   color: #65737e;  
}
 
.container-2 input#search::-moz-placeholder {  /* Firefox 19+ */
   color: #65737e;  
}
 
.container-2 input#search:-ms-input-placeholder {  
   color: #65737e;  
}

.container-2 .icon{
  position: absolute;
  top: 50%;
  margin-left: -25px;
  margin-top: 17px;
  z-index: 1;
  color: #ffffff;
}

.container-2 input#search:focus, .container-2 input#search:active{
  outline:none;
  width: 300px;
}
 
.container-2:hover input#search{
width: 300px;
}
 
.container-2:hover .icon{
  color: #000000;
   
}

/*Expandable Search CSS End*/

<link href="http://ift.tt/1oKzmdw" rel="stylesheet">
  <div class="container-2">
      <span class="icon"><i class="fa fa-search"></i></span>
<form role="search" class="search-form" action="http://ift.tt/1vzc6T2" method="get">      
<input type="search" class="search-field" id="search"    placeholder="Search …"  name="s" title="Search for:">
</form>  
</div>

HTML Code I am using in Text widget . This is a wordpress website and

Thanks

via Chebli Mohamed