Because ja t3v3 blank is using bootstrap and less you need to understand anything before inprocess to change it
<blockquote>Open plugins/system/jat3v3/t3v3base/bootstrap/less/mixins.less file</blockquote>
from
.container-fixed() {
margin-right: auto;
margin-left: auto;
.clearfix();
}
change
.container-fixed() {
.clearfix();
}
<blockquote>Open templates/ja_t3v3_blank/less/layout.less file</blockquote>
from
.wrap {
width: auto;
clear: both;
}
change
.wrap {
width: 800px;
clear: both;
}
<blockquote>Open templates/ja_t3v3_blank/less/variables.less file</blockquote>
from
// 1200px min
@T3gridWidth1200: 1200px; // T3 add
@gridGutterWidth1200: 40px;
@gridColumnWidth1200: floor((@T3gridWidth1200 - @gridGutterWidth1200 * (@gridColumns - 1)) / @gridColumns);
@gridRowWidth1200: (@gridColumns * @gridColumnWidth1200) + (@gridGutterWidth1200 * (@gridColumns - 1));
change to
// 1200px min
@T3gridWidth1200: 800px; // T3 add
@gridGutterWidth1200: 40px;
@gridColumnWidth1200: floor((@T3gridWidth1200 - @gridGutterWidth1200 * (@gridColumns - 1)) / @gridColumns);
@gridRowWidth1200: (@gridColumns * @gridColumnWidth1200) + (@gridGutterWidth1200 * (@gridColumns - 1));