- Create new css class with name your theme.

CSS

div.jfilestyle.jfilestyle-theme-custom input {
	border: 1px solid orange;
}
div.jfilestyle.jfilestyle-theme-custom label {
	border-color: orange;
	background: orange;
	color: #fff;
}

HTML

<input type="file" class="jfilestyle" data-theme="custom">

JavaScript

$(":file").jfilestyle({theme: "custom"});

Example:

// Via JavaScript:
$(":file").jfilestyle({text: "<span class='oi oi-folder'></span>"});

// Via data attributes:
<input type="file" class="jfilestyle" data-text="<span class='oi oi-folder'></span>">