<div class="models">
  <button class="btn">
    <span class="btn-text">
      Hello
    </span>
  </button>
</div>

:root {
  
  --primary: #080808;
  --secondary: #97CEE0;
  --white: #ffffff;
  --secondary-blue: #556FBA;
  --tertiary-blue: #314589;
}

.description {
  
  position: relative;
  display: block;
  z-index: 3;
  color: var(--white);
}

.btn {
  
  position: relative;
  cursor: pointer;
  border: none;
  font-family: 'Lexend Zetta', sans-serif;
  color: var(--white);
  background: transparent;
  overflow: hidden;
  border-radius: 25px;
  
  &:after {
    
    content: '';
  background: linear-gradient(to right, #c21500, #ffc500); /* W3C, IE 10+/ Edge, Firefox 16+, Chrome 26+, Opera 12+, Safari 7+ */

    position: absolute;
    top: 50%;
    left: 50%;
    height: 300px;
    width: 300px;
    transform: translate(-50%, -50%) rotate(0deg);
    transition: all 2s ease-in;
  }
  
  &-text {
    
    background: var(--primary);
    padding: 1.25rem 6rem;
    font-size: 1.5rem;
    position: relative;
    z-index: 1;
    display: block;
    margin: 0.25rem 0;
    border-radius: 23px;
  }
}

.models {
  
  width: 100%;
  height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--primary);
  
  .btn {

    &:hover {

      &:after {
        
        content: '';
        transform: translate(-50%, -50%) rotate(720deg);
        transition: all 2s ease-in-out;
      }
    }
  }  
}