I have actually a tiled background on my "header", "main content", "alternate content" and "footer" style settings.
Now I would like to add an SVG image semi-transparent background, like a layer on my tiled background.
Normally the syntax with css3 is like :
background-image: url(img/semi-transparent-fond.svg), url(img/tiled-background.png);
background-size: 100% 100%, auto;
background-position: left top, left top;
background-repeat: no-repeat, repeat;
background-attachment: fixed, fixed;
and it works fine but how can I add this on my choice theme ?