Css dropshadow curvature issue on blink based browsers

I first thought it was an awesome effect making the post look like they stand out like a paper.

But discovered that on firefox the dropshadow is perfectly strait and then I saw on very long post like Install Apache , MariaDB(Mysql),PHP (LAMP)

The upper pard of the shade overflows with solid colors.

See screenshot, chromium on the right has no addons or plugins.

I know about is only seen on large posts, not a big issue.

.topic-post .topic-body.clearfix:before, .topic-post .topic-body.clearfix:after
replace top: 80%; by height:15px;