f91f09

Hello, I'm having a little trouble trying to change the background color of my return to top button. Can someone help me out with the correct code to get this color working?  #f91f09

 <!--Top button -->
<script src="./topbutton/jquery-1.11.3.min.js"></script>
<script src="./topbutton/topbutton.min.js"></script>
<script>
$(document).ready(function(){
//Top Button
$.topbutton({
htlm : "<i>Top</i>", //String
css : "width:50px; height:50px; background color: #f91f09; border:false; font-size:20px;", //String
scrollAndShow : true, //Boolean
scrollSpeed : 1000 //Number
});

if ($('div.wrapperChat').length)
$('div.wrapperChat')
.closest('#bx-content-container')
.parent()
.css('height', 'calc( 100vh - 9rem )');

});
</script>
<style>
.bx-tl-post .bx-form-value .bx-form-input-wrapper-textarea {
overflow: unset;
}
</style>
<!--End Top Button -->

Thank you in advance...