Susy: How to extend content box to cover grid-padding as well? - css

Question

I just started to play with Susy. I have a 12 column grid that has grid-padding on it. Now i want the header of my page to span the whole grid including the grid-padding. What I'm doing right now is calculating the overall width and then setting a negative margin on the header. That's feels rather hacky to me... Is there a cleaner way to do it?
$total-columns : 12;
$column-width : 3.5em;
$gutter-width : 1.25em;
$grid-padding : 2em;
$total-width: ( $total-columns * ($column-width + $gutter-width) ) + ( 2 * $grid-padding ) - $gutter-width;
header {
height: 150px;
width: $total-width;
margin-left: -$grid-padding;
}

Answer 1

You have two good options. One is a simplified version of what you have. Since block elements are 100% width by default, you can simply eliminate your width setting (and all that hacky math).
header {
height: 150px;
margin: 0 0 - $grid-padding;
}
Your other option is to use multiple containers on the page. That requires a change to the markup, but sometimes it's a simplification that works well. If you move the header outside your current container, and declare it as a container of it's own, that will do the trick.
(as a side note: if you do need the full width ever, you can simply use the columns-width() function (for inner width, without padding) or container-outer-width() for the full width including the padding.)
UPDATE:
I've been using this mixin, to apply bleed anywhere I need it:
#mixin bleed($padding: $grid-padding, $sides: left right) {
#if $sides == 'all' {
margin: - $padding;
padding: $padding;
} #else {
#each $side in $sides {
margin-#{$side}: - $padding;
padding-#{$side}: $padding;
}
}
}
Some examples:
#header { #include bleed; }
#nav { #include bleed($sides: left); }
#main { #include bleed($sides: right); }
#footer { #include bleed(space(3)); }