css

I am using the plugin as a side scroll box popup. I want to narrow the box I have tried to add .mailmunch-scrollbox {
width: 20%;
}

to a custom CSS but since its inline it does not take. How can I narrow the optin box.

http://aqualogixfitness.com

Thanks

Rick

https://ww.wp.xz.cn/plugins/aweber-forms-by-mailmunch/