Code css hover image border cho website wordpress

Tạo 1 block HTML và chèn code HTML như bên dưới

<div class="nhatdev">
  <a href=""><img src="https://theme.hstatic.net/1000340279/1000431896/14/large_banner_2_image.jpg?v=7">
  <span class="effect-line"></span>
    </a>
</div>

Sau đó chèn CSS vào file style.css

a{
  width:100%;
  float:left;
      position: relative;
    z-index: 1;
    text-align: center;
}
a img{
      display: block;
    max-width: 100%;
    height: auto;
}
a img:after{
      content: '';
    position: absolute;
    z-index: 1;
    width: 100%;
    height: 0;
    top: 0;
    left: 0;
    -moz-transition: all 500ms ease;
    -webkit-transition: all 500ms ease;
    -o-transition: all 500ms ease;
    transition: all 500ms ease;
    -moz-backface-visibility: hidden;
    -webkit-backface-visibility: hidden;
    backface-visibility: hidden;
    background: rgba(0, 0, 0, 0.18);
}
.effect-line{
  position: absolute;
    content: "";
    top: 0;
    right: 0;
    left: 0;
    bottom: 0;
    z-index: 1;
}
.effect-line:before {
    z-index: 1;
    content: "";
    position: absolute;
    left: 10px;
    right: 10px;
    top: 10px;
    bottom: 10px;
    border-top: 2px solid #fff;
    border-bottom: 2px solid #fff;
    transform: scale(0, 1);
    -moz-transform: scale(0, 1);
    -webkit-transform: scale(0, 1);
    -ms-transform: scale(0, 1);
    transition: all 0.4s ease-in-out 0s;
    -moz-transition: all 0.4s ease-in-out 0s;
  -webkit-transition: all 0.4s ease-in-out 0s;
}
.effect-line:after {
    z-index: 1;
    content: "";
    position: absolute;
    left: 10px;
    right: 10px;
    top: 10px;
    bottom: 10px;
    border-left: 2px solid #fff;
    border-right: 2px solid #fff;
    transform: scale(1, 0);
    -moz-transform: scale(1, 0);
    -webkit-transform: scale(1, 0);
    -ms-transform: scale(0, 1);
    transition: all 0.4s ease-in-out 0s;
    -moz-transition: all 0.4s ease-in-out 0s;
    -webkit-transition: all 0.4s ease-in-out 0s;
}
a:hover .effect-line:before{
  transform:scale(1,1);
}
a:hover .effect-line:after{
  transform:scale(1,1);
}