How do I control (increase) width of Site – Page – Content Area?

Hi all,

Somewhat new to WP and css. I installed twentyfourteen and created a child theme…..

Goal: to Control (increase) width of Site & Page & Content Area?

Issues:
– the whole site seems to be about 960 width – I would like more
– the center page (I tried full width template) content seems to have large white margin on both sides of page – I would like more text left to right and less width

How do I do this?

things I added to child that are not changing anything yet

html .mceContentBody {
font-size: 100%;
max-width: 900px;
}

body {
margin: 0 auto;
max-width: 1600px;
}

.site {
background-color: #fff;
max-width: 1800px;
position: relative;
}