.youtube-thumb {
  position: relative;
  display: inline-block;
}

.youtube-thumb img {
  width: 360px;
  max-width: 100%;
  display: block;
}

.play-button {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);

  width: 70px;
  height: 70px;
  border-radius: 50%;
  background: rgba(255, 0, 0, 0.8);
}

.play-button:after {
  content: "";
  position: absolute;

  top: 50%;
  left: 50%;

  transform: translate(-40%, -50%);

  width: 0;
  height: 0;

  border-top: 12px solid transparent;
  border-bottom: 12px solid transparent;
  border-left: 20px solid white;
}