It is possible just include one css
http://maxcdn.bootstrapcdn.com/bootstrap/3.2.0/css/bootstrap.min.css
HTML
<input type="text" class="input-style" placeholder="Text input"></input>
CSS
.input-style {
width: 400px;
height: 35px !important;
margin-bottom: 10px !important;
padding: 6px 12px !important;
font-size: 14px;
line-height: 1.42857143;
color: #555;
-webkit-border-radius: 6px;
-moz-border-radius: 6px;
border-radius: 6px;
}
.input-style {
width: 400px;
height: 35px !important;
margin-bottom: 10px !important;
padding: 6px 12px !important;
font-size: 14px;
line-height: 1.42857143;
color: #555;
-webkit-border-radius: 6px;
-moz-border-radius: 6px;
border-radius: 6px;
}
<link href="http://netdna.bootstrapcdn.com/twitter-bootstrap/2.2.2/css/bootstrap-combined.min.css" rel="stylesheet"/>
<input type="text" class="input-style" placeholder="Text input"></input>