Hi, Separate issue, Security : Please update Flash 20.0 r0 very very insecure. Flash Player Version: 29.0.0.113 Current Version https://get.adobe.com/flashplayer/otherversions/ Step 1: Select Operating System Step 2: Select A Version (Firefox, . . . .) Note: Other software is offered in the download. <Windows Only> Would go to the 3 Bar Menu then Add-ons and look for that program and uninstall or disable it. Youtube has a built in dark theme : https://lifehacker.com/enable-youtubes-secret-dark-theme-the-easy-way-1798137898 Please let us know if this solved your issue or if need further assistance.