I added via Template styles >> JA Colab >> Tools >> edit custom css
The generated css file is:
/home/public_html/templates/ja_colab/local/css/custom.css
If you have you custom css code in this file: /home/public_html/templates/ja_colab/css/custom.css
Please copy it to: /home/public_html/templates/ja_colab/local/css/custom.css