如何制作固定横幅以便内容流过它？

all searched every where and tried alot after that i'm to get help from here i have a banner and some divs below it but when i make banner position fixed the below it comes one the back of banner and banner shows over that div ....the div suppose to be right below after that fixed banner don't want to use 'top'property of css and if i use margin-top al content comes down leaving white space on the topall searched every where and tried alot after t