Hot to style big search box

if you want to add custom styling for input fields on Big search you will need to override default CSS,

.big-search-box{
/* Main Container CSS Here */
background: #70dcff none repeat scroll 0 0;


}
.big-search-box .keyword-wrap {
/* Keyword input CSS Here */
background: #fff none repeat scroll 0 0;
}

.big-search-box .job-location {
/* Location Input CSS Here */
background: #fff none repeat scroll 0 0;
}

.big-search-box .job-submit {
/* Submit Button CSS Here */
background: #309bbe none repeat scroll 0 0;
}

you may need to use !important to override.