body {
  background: #000;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
}

.flame {
  width: 150px;
  height: 150px;
  background: linear-gradient(-45deg, red, orange);
  border-radius: 150px 150px 0px 150px;
  -webkit-transform: rotate(-135deg);
          transform: rotate(-135deg);
  -webkit-animation: .1s flame infinite;
          animation: .1s flame infinite;
  -webkit-filter: blur(10px);
          filter: blur(10px);
  position: relative;
  box-shadow: 17px 20px 90px #700;
  border: 45px solid black;
  border-left-width: 25px;
  border-top-width: 25px;
}
.flame:after, .flame:before {
  content: '';
  width: 100px;
  height: 100px;
  display: block;
  position: absolute;
  background: linear-gradient(-45deg, red, orange);
  -webkit-animation: .2s flame infinite;
          animation: .2s flame infinite;
  -webkit-transform: scale(0.8) rotate(20deg);
          transform: scale(0.8) rotate(20deg);
  border-radius: 100px 100px 0px 100px;
  top: 20px;
}
.flame:before {
  top: 0;
  -webkit-animation-duration: .09s;
          animation-duration: .09s;
  -webkit-transform: scale(0.9) rotate(-15deg) translate(10px, 0px);
          transform: scale(0.9) rotate(-15deg) translate(10px, 0px);
}

@-webkit-keyframes flame {
  0% {
    height: 150px;
    width: 150px;
  }
  50% {
    height: 140px;
    width: 140px;
  }
  100% {
    height: 150px;
    width: 150px;
  }
}

@keyframes flame {
  0% {
    height: 150px;
    width: 150px;
  }
  50% {
    height: 140px;
    width: 140px;
  }
  100% {
    height: 150px;
    width: 150px;
  }
}