>>/13/
I forgot to make some selectors more specific.

For now do the following

Change (line 147) from:
.opHead a[id^="hide"] {
to
.opHead a[id^="hide"][id*="Thread"] {

Change (line 168) from:
.innerPost a[id^="hide"] {display: none;}
to
.innerPost a[id^="hide"][id*="Post"] {display: none;}

By changing those two lines, the removal of lines 143-144 should bring back Hide User Posts properly.

I recommend making Hide User slightly less distracting by reducing its font size by adding:
/* Reduce Hide User font size */
a[id^="hide"][id*="User"] {font-size: 0.85em;}

For the next revision I plan to format the stylesheet better so that the removal of featuring-hiding lines like these is a little more straightforward. I also want to make some adjustments to the catalog page as well as try to fix the inconsistent font sizes in the iPhone's Safari browser. I want to get these bugs fixed before I start making the other color schemes (regular Yotsuba and Yotsuba Green).