small {
  /*margin: 10rem 0 0 10rem;*/
  padding: 1.5rem 2.5rem;
  border: none;
  outline: none;
  background-image: linear-gradient(to top left, rgb(57, 176, 255) 60%, #fff);
  color: white;
  letter-spacing: 0.5rem;
  font-size: 2rem;
  box-shadow: 1rem 1rem 4rem #808080;
  position: relative;
  overflow: hidden;
}

small span:nth-child(1) {
  position: absolute;
  height: 2px;
  width: 100%;
  /*background-image: linear-gradient(
    to right,
    rgb(0, 153, 255) 30%,
    rgb(203, 6, 230) 40%,
    rgb(57, 176, 255)
  );*/
  background: linear-gradient(90deg, rgb(255, 6, 99), #fff);
  top: 0;
  left: 0;
  animation: line1 2s linear infinite;
}

@keyframes line1 {
  0% {
    transform: translateX(-100%);
  }
  100% {
    transform: translateX(100%);
  }
}

small span:nth-child(2) {
  position: absolute;
  /*height: 100%;
  width: 0.2rem;*/
  height: 100%;
width: 2px;
 /* background-image: linear-gradient(
    to bottom,
    rgb(0, 153, 255) 30%,
    rgb(203, 6, 230) 40%,
    rgb(57, 176, 255)
  );*/
  background: linear-gradient(180deg, rgb(8, 251, 24), #fff);
  top: 0;
  right: 0;
  animation: line2 2s linear 1.5s infinite;
}

@keyframes line2 {
  0% {
    transform: translateY(-100%);
  }
  100% {
    transform: translateY(100%);
  }
}

small span:nth-child(3) {
  position: absolute;
  width: 100%;
height: 2px;
  /*height: 0.2rem;
  width: 100%;*/
  /*background-image: linear-gradient(
    to right,
    rgb(0, 153, 255) 30%,
    rgb(203, 6, 230) 40%,
    rgb(57, 176, 255)
  );*/
  background: linear-gradient(270deg, rgb(8, 251, 24), #fff);
  bottom: 0;
  left: 0;
  animation: line3 1s linear infinite;
}

@keyframes line3 {
  0% {
    transform: translateX(100%);
  }
  100% {
    transform: translateX(-100%);
  }
}

small span:nth-child(4) {
  position: absolute;
  height: 100%;
width: 2px;
  /*height: 100%;
  width: 0.2rem;*/
  /*background-image: linear-gradient(
    to bottom,
    rgb(0, 153, 255) 30%,
    rgb(203, 6, 230) 40%,
    rgb(57, 176, 255)
  );*/
  background: linear-gradient(0deg, rgb(255, 6, 99), #fff);
  top: 0;
  left: 0;
  animation: line4 2s linear 1.5s infinite;
}

@keyframes line4 {
  0% {
    transform: translateY(100%);
  }
  100% {
    transform: translateY(-100%);
  }
}