Hi.
I set the color icons by following the step by step tutorial
Display by color
The only css code I used was inserted at the end of the file frontend_custom.css
.hikashop_product_characteristics_table td img {border: 2px groove black;}
.hikashop_product_characteristics_table td label {display:inline !important; padding-left: 5px;}
.hikashop_filter_color br{ display: none;}
.hikashop_filter_checkbox label{border: 2px solid black; display: inline-block !important; margin: 4px;}
.hikashop_filter_checkbox a {display: none;}
.hikashop_filter_checkbox input{ margin-right:5px; display:none;}
label.radio input.inputbox, span.hikashop_filter_checkbox input {display: none;}
So I really do just what I read on your site. I was hoping that you already have a ready-made solution that would be an extension of this tutorial, to use the effect "color icon" also for the pdf invoice.
If you gave some more detailed hint of what to do to modify php, because for now I do not know where to start.