To make this work, clone the repo locally, stop kibana, drag the custom_css folder into the plugins folder (usually at /usr/share/kibana/plugins), change <yourbase64image> in main.less to a 64 bit encoded svg image, then start Kibana.
In order for new plugins to work, Kibana needs to rebundle.
Simply delete the 'optimize' folder and Kibana will be forced to rebundle again.
If you want to change the logo when Kibana first loads, change src/core/server/rendering/views/styles.jsand adjust <yourbase64image>. You may need to adjust some of the margins to center your logo correctly.
.kibanaWelcomeLogo {
width: 60px;
height: 60px;
margin: 10px 0 0px 10px;
background-repeat: no-repeat;
background-size: contain;
background-image: url('data:image/svg+xml;base64,<yourbase64image>');
}
To change the start-up text "Loading Kibana", look in src/core/server/rendering/views/template.js.
If you want to change the logo on the Space Selector, please go to x-pack/legacy/plugins/spaces/public/space_selector/space_selector.tsx , search for logoKibana and change it to your svg icon, as explained here.