Thread:Project:Support desk/error in css

hi I get this error when using this css code

background-image: url('//upload.wikimedia.org/wikipedia/commons/1/10/Wikipedia-logo-v2-200px-transparent.png'), -moz-linear-gradient(top, #ddd, #000); background-image: url('//upload.wikimedia.org/wikipedia/commons/1/10/Wikipedia-logo-v2-200px-transparent.png'), -ms-linear-gradient(top, #ddd, #000); background-image: url('//upload.wikimedia.org/wikipedia/commons/1/10/Wikipedia-logo-v2-200px-transparent.png'), -o-linear-gradient(top, #ddd, #000); background-image: url('//upload.wikimedia.org/wikipedia/commons/1/10/Wikipedia-logo-v2-200px-transparent.png'), -webkit-linear-gradient(top, #ddd, #000); background-image: url('//upload.wikimedia.org/wikipedia/commons/1/10/Wikipedia-logo-v2-200px-transparent.png'), -webkit-gradient(linear,

Warning: Background image '//upload.wikimedia.org/wikipedia/commons/1/10/Wikipedia-logo-v2-200px-transparent.png' was used multiple times, first declared at line 96, col 3.

please aslo visit http://en.random-wikisaur.tk/wiki/MediaWiki:Common.css please because it shows many error.