Single event – Width displays wrong

I am unable to get the single event info page to display properly. The detail information (on the side) is cut off. I have tried using both default and modern styles. I also added the following to the custom CSS in hopes it would work.

@media only screen and (max-width: 960px) and (min-width: 768px)
.mec-container {
width: 600px;
}

What am I missing? Thanks for your help.

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