Rersposnive Design require width in percentage

hi there,
I am working on website at http://www.itecuae.com/demo20/, which uses this great plugin !

The issue is that it currently looks perfect on Desktop (1024X768) resolution. But when viewed on wider screen, it uses the same width of 850px. So I would like to provide Width as percentage, say 95%.

So how to go about it ?

Thanks in anticipation !

https://wordpress.org/plugins/logo-slider/