Resume | Div Block Disappear


#1

I have created 4 div's in html file; but while CSS styling one of the div disappear itself as shown here in this picture:

The pre CSS code and its output is given in above picture:

However the post CSS code and its output is given in the above picture too:

Question: I'm confused of why one of the div disappear when i added 2 lines of code in post CSS image i.e.
z-index:1;
position:fixed;


#2

position: fixed take the #header out of flow, so your (i think, not 100% sure) your .left shifts under your header. try adding: margin-top: 50px; to .left, see what it does