With the File Uploader, you track the progress of your uploads with the circle being filled with color during the process. The fill color can be changed via the CSS color property, while border-color will work for your background.
.uploadcare--widget_status_loaded
.uploadcare--widget_status {
display: inline-block !important;
}
.uploadcare--progress_type_canvas {
color: #56a8ff;
border-color: #d4dfe5;
}
Check out the live demo.