We all use Youtube everyday but very know that Youtube has a Dark Theme. The Company has not made it official but you can still use it. Follow the steps to enable the dark theme on Youtube. Steps: Sign in to your Youtube account. It is necessary. With out sign in, trick will not work. Right click and choose Inspect ('in Chrome') or Inspect Element ('in Firefox') option. It will open a window that contains code of Youtube and multiple tabs. Now click on 'console' tab. Copy and paste the code given below (without quotes) and hit Enter. If you get warning then simply click on 'allow pasting'. If you get error then copy and paste again and hit Enter. var cookieDate = new Date(); cookieDate.setFullYear(cookieDate.getFullYear( ) + 1); document.cookie="VISITOR_INFO1_LIVE=fPQ4jCL6EiE; expires=" + cookieDate.toGMTString( ) + "; path=/"; If it successfully runs then refresh the Youtube page.