Hi babyzsmile !
You can add green color for template following steps below :
1. Create a file green.css in templates/ja_senecio/css/colors folder
2. In templates/ja_senecio/templateDetails.xml file find following code section :
<param name="ja_color" type="list" default="default" label="Color Variation" description="Color variation to use">
<option value="fresh">Fresh</option>
<option value="warm">Warm</option>
</param>
change to :
<param name="ja_color" type="list" default="default" label="Color Variation" description="Color variation to use">
<option value="fresh">Fresh</option>
<option value="warm">Warm</option>
<option value="green">Green</option>
</param>