Set the width of the captions on a mobile separately

I have the width of the text on my blog set to 600px:

.inside-article .entry-content, #comments {
max-width: 600px;
}

I also have the width of image captions set at 600px:

.wp-caption .wp-caption-text {
width: 600px;
}

This works fine on my desktop but the captions bleed off the right side on a mobile.

Is there some CSS code that I can use to set the width of the captions on a mobile separately?