To play around with the width for your copyright information, try this . . .
File path –> t3-assets/dev/plugins.system.t3.base.less.grid-ext-responsive.less.css
at line 55, play around with the pixel value, for example . . .
.span3 {
width: 350px;
}
As for the background color for the footer section, look to the following:
File path –> i/t3-assets/dev/templates.ja_beranis.less.style.less.css
at line: 472
.t3-footer {
color: #666666
}
Though it is probably best if you create a “custom.css” file and put your modified CSS within it – to protect your changes when/if you try to update your template.