The best option is to get the styles with firebug and add the changes to your template css.

The correct CSS syntax would be:
div#extcal_minical table{width:100% !important;}

You can obviously make the width whatever you want, but this makes it fill the to the width of the containing module.

The "#extcal_minical" div is already set to 100%, but the table has some other width - so just over-ride that. Make sure you put in the !important; part at the end of your declaration because otherwise JEvents own css will most likely cascade over yours.

Could you tell me where exactly to find the css file to edit, please?

It's just that I've been in the mod_jevents_cal folder but can only see php files.

Many thanks.

Ess

Use Firefox and Firebug to locate it and change it, once your happy copy your changes to your sites template.css with !important on the css code to overwrite the default code.

Thanks, TonyP.
I found the style sheet (modstyle.css). The width was set to 140px (!important), so I changed it to 100%.

It's all sorted and I'm all good.

Ess