.gradient-box {
  
    display: flex;
    align-items: center;
    //width: 50vw;
    width: 90%;
    margin: auto;
    max-width: 22em;
  
    position: relative;
    padding: 30% 2em;
    box-sizing: border-box;
  
    $border: 5px;
    color: #FFF;
    background: #000;
    background-clip: padding-box; /* !importanté */
    border: solid $border transparent; /* !importanté */
    border-radius: 1em;
  
    &:before {
      content: '';
      position: absolute;
      top: 0; right: 0; bottom: 0; left: 0;
      z-index: -1;
      margin: -$border; /* !importanté */
      border-radius: inherit; /* !importanté */
      background: linear-gradient(to right, blue, orange);
    }
  }