How remove "open app tumblr" message?

I found this solution suggested by u/felix4343 and it solved my issue at least on Android:

tumblr_controls, .tmblr-iframe{display:none!important;}

Also, I was using this piece of code before stumbling upon the mobile issue and it was working for PC:

.tmblr-iframe-compact .tmblr-iframe--unified-controls {display: none!important;}

In doubt, like me, test both:

.tmblr-iframe-compact .tmblr-iframe--unified-controls {display: none!important;}

tumblr_controls, .tmblr-iframe{display:none!important;}

Pay attention because you might not find an easy way to edit your theme anymore, but you can still find the panel by just clikcing on your blog from the dashboard or directly at www.tumblr.com/customize/[yourblog].