Animated Gradient Border In Pure CSS

A fancy animated box border design concept that makes a gradient line cyclically move along the border of the element.

How to use it:

1. Apply a gradient border to the target element.

<div class="demo"></div>

div.demo {
  width: 250px;
  height: 250px;
  box-shadow: 16px 14px 20px #0000008c;
  border-radius: 10px;
  position: relative;
  overflow: hidden;
  display: flex;
  justify-content: center;
  align-items: center;
}
div.demo::before{
  content: "";
  /* override the gradient here */
  background-image: conic-gradient(
    #ff0052 20deg,
    transparent 120deg
  );
  width: 150%;
  height: 150%;
  position: absolute;
  animation: rotate 2s linear infinite;
}
div.demo::after{
  content: "CSSScript";
  width: 240px;
  height: 240px;
  background: #101010;
  position: absolute;
  border-radius: 10px;
  display: flex;
  justify-content: center;
  align-items: center;
  color: #ff0052;
  font-size: larger;
  letter-spacing: 5px;
  box-shadow: inset 20px 20px 20px #0000008c;
}

2. Animate the gradient border using the CSS rotate property.

@keyframes rotate {
  0%{
    transform: rotate(0deg);
  }
  100%{
    transform: rotate(-360deg);
  }
}