The solution above is great for Firefox, but it's screwing up display in mobile phones.
This is how to optimize for both Firefox and mobile phones.
Enter the width, but no height... unlocked
then, enter: max-width: 100%;
This has worked great in a simple template with simple modules.
In some instances I had to add: height:auto;
>> It can't be saved from the window:
so add it if necessary from the HTML view.
Generally, I found it very difficult to optimize a template made with the builder for mobile phones, especially in the sections with squared or rounded images.
Any one has a complex template made with the builder that displays well in mobiles?