@katklopp

Found it!

Alright, so for anyone with Oxygen theme trying to make their posts full width and retain the left sidebar. Just stick this in your CSS and you’re good.

#content {
	float: left;
	width: 100%;
	margin: 0 0 30px;
}
.entry-header {
    float: left;
	width: 100%;
}
.hentry .featured {
    margin-bottom: 15px;
    width: 100%
}

When I just change the #content width to 100%, it makes the post header bar and text full width, but not the photos, which are my main concern. I’m assuming I need to locate that line in the code and change it to 100% too? Or should I adjust the pixel dimensions. I opened style.css from my parent theme in dw and the #content is currently like this:

#content {
	float: left;
	width: 62.66666666666667%;	/* 470 / 750 = 0.6266666666666667 */
	margin: 0 0 30px 0;
}

am I on the right track? Think I’m looking at the wrong lines of code to change the photo width?

Thanks @roamingpro

Here’s a dumb follow-up question. When creating my child theme, do I retain the author, author url, and theme url from the original oxygen theme?

Like this:

Theme URI: http://alienwp.com/oxygen-child/
Author: AlienWP
Author URI: http://alienwp.com