.typing-indicator::after {
     content: '...';
     animation: typing 1.5s infinite steps(4, end);
 }

 @keyframes typing {

     0%,
     100% {
         content: '';
     }

     25% {
         content: '.';
     }

     50% {
         content: '..';
     }

     75% {
         content: '...';
     }
 }