What is this vertical transparent line appearing only on Safari Mac?

Question

I've designed this page on Google Chrome, and it displays nicely. However if you check it on Safari Mac (Safari Windows displays it well) and it has a strange vertical line :

The line seems to be transparency of the white area (if I change the background color, it changes the line color). Another funny thing : there's an horizontal offset where the title is (the line is cut and moved to the left of the page)... a hint ?

I've inspected the elements, but there's no reason I can find.

Any help ?

Answer 1

As per this reply: Stray vertical line above 965 pixels with border radius in Safari

You should add -webkit-background-clip: padding-box; to your containing class.