Page background color only rendered in Inkscape

Migrated from: https://bugs.launchpad.net/inkscape/+bug/1800536

Hello, Im able to change background color of svg Document properties > background in Inkscape. But this color is not rendered by other viewers (browser, image viewers, etc) only in Inkscape. Workaround is to manualy edit file and put svg { background: rgb(0, 0, 0); }.

Is possible to put some gui in Inkscape to edit real background? Or to save background color from properites as correct css style to svg?

Workaround (as Sozi app does) is to read background color from svg pagecolor and style it externaly:

svg {background: rgba(56, 128, 131, 1); }

And next problem - by default it also didnt work because you didnt notice opacity of background set to 0. Opacity value doesnt affect background color in Inkscape, in other apps is it rendered correctly and you dont notice it by first time:

Opacity 0 (default):

Opacity 255:

http://sozi.baierouge.fr/community/d/65-change-background-of-svg/7