.st-video-popup .vc_figure { 
  position: relative; 
}

.st-video-popup .box { 
  position: absolute; 
  bottom: 15px; 
  left: 15px; 
  margin: 10px; 
  width: 60px; 
  height: 60px; 
  border-radius: 0; 
  border: none; 
  cursor: pointer; 
  background:inherit;
}

.st-video-popup .tri { 
  position: relative; 
  top: 40%; 
  left: 47%; 
  width: 0;  
  height: 0; 
  border-top: 7px solid transparent; 
  border-bottom: 7px solid transparent; 
  border-left: 9px solid #fff; 
}

.box {
    position: relative;
    z-index: 0;
}

.box:before {
    content: "";
    position: absolute;
    z-index: -1;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: #282e3f;
    transform: scaleX(0);
    transform-origin: 0 50%;
    transition: transform .3s ease-in-out;
}

.box:hover:before {
    transform: scaleX(1);
}