CSS keeps self-changing

Curious why the CSS keeps changing — the format of it stays nice and neat, but the colors of certain elements keep changing. When I logged in this morning, the border was within my color theme, but the wrong color. I took it out of the sidebar and re-added it. Now, the border is fine but the double-underline beneath the title is the wrong color. Any ideas?

http://ww.wp.xz.cn/extend/plugins/genesis-latest-tweets/