Messed with some stuff in the browser, hopefully this helps.

Look for:

#primary > .inner:first-child {
padding: 0 3em;
}

Change it to:

#primary > .inner:first-child {
padding: 0;
}

If you can't find that bit, just paste the change-to into the stylesheet at the bottom, and it should override.

That should reduce the margins and make it a little better for mobile.

For headers, didn't bother fixing comments with icons, but...

Find this:

.comment .header {
background: #F17892;
color: #ffffff;
padding: 5px 2px 5px 2px;
}

and change it to this:

.comment .header {
background: #F17892;
color: #ffffff;
padding: 5px 2px 25px 2px;
}

then find this:

.entry .contents, .comment .contents {
margin: 1em 0;
}

and change it to this:

.entry .contents, .comment .contents {
margin: -25px 0 1em 0;
}

and that should move the From: (Anonymous) up into the header

Finally, optionally, find this:

.comment-poster, .poster-ip {
background: #F17892;
color: #ffffff;
padding: 5px 2px 5px 2px;
}

and change it to this

.comment-poster, .poster-ip {
padding: 5px 2px 5px 2px;
}

then find this:

.comment-poster .ljuser a {
color: #ffffff;
}

and just delete it. That'll get rid of the pink background on the inline From: (Anonymous) and make it so you can still see the names of logged-in users

Hopefully I caught everything, and hopefully that doesn't fuck everything up.