To apply custom CSS stylesheets to your Heatmaps and Session Recordings, prefix your CSS with “html.piwikHsr”.
To apply custom stylesheets only for Heatmaps, prefix your CSS with “html.piwikHeatmap”.
To apply custom stylesheets to Session Recordings, prefix your CSS with “html.piwikSessionRecording”.
Custom stylesheets can be useful to prevent any possibly sensitive data from being shown in a heatmap or a session recording. It can be also useful when your website shows a pop-up when a user lands on your website. Under circumstances such a pop-up could be visible in a heatmap. You can also exclude or hide elements when you configure a heatmap, but by defining it in your stylesheets you don’t have to configure it each time you create a new heatmap.