Untitled

<!DOCTYPE html>
<html>

  <head>
    <link rel="stylesheet" href="style.css">
  </head>

  <body>
    
    
  <br>
  <div class="box">пример рамки</div>
  <br>
    
    
    
  </body>

</html>

/* Styles go here */
.box{
    text-align: center;
    width: 300px;
	  border: 1px solid transparent;
	  -moz-border-image: -moz-linear-gradient(left, #FFFFFF 0%, #00CCFF 50%, #FFFFFF 100%);
	  -webkit-border-image: -webkit-linear-gradient(left, #FFFFFF 0%, #00CCFF 50%, #FFFFFF 100%);
	  border-image: linear-gradient(to left, #FFFFFF 0%, #00CCFF 50%, #FFFFFF 100%);
	  border-image-slice: 1;
	}