#1

 .dm-right-tab-content-active {
        
       
        animation: rightTabReveal 0.5s forwards;
        display: block; /*change to flex if using container*/
        
    }
    
 #2
 
  //change block to flex if using container
        dmRightTabs[currentIndex].style.display = 'block';
        dmRightTabs[currentIndex].classList.add('dm-right-tab-content-active');