.video-11{
    background-repeat: no-repeat;
    background-position: center;
    background-size: cover;
    height: 100vh;
    width: 100vw;
    background-image: url("../img/shadow.jpg");
}
.video-11 h1{
    font-size: 5rem;
}
.videobtn{
    margin-left: 2rem;
    animation:infinite ease-in-out;
    animation-name: example;
    animation-duration: 3s;
}
@keyframes example {
    0%   {box-shadow:0 0 2px 2px rgb(255, 255, 255);}
    10%  {box-shadow:0 0 4px 4px rgba(255, 255, 255, 0.904);}
    20%  {box-shadow:0 0 6px 6px rgba(255, 255, 255, 0.801);}
    30% {box-shadow:0 0 8px 8px rgba(255, 255, 255, 0.705);}
    40%   {box-shadow:0 0 10px 10px rgba(255, 255, 255, 0.5);}
    50%  {box-shadow:0 0 12px 12px rgba(255, 255, 255, 0.836);}
    60%  {box-shadow:0 0 14px 14px rgba(255, 255, 255, 0.007);}
    70% {box-shadow:0 0 16px 16px rgba(255, 255, 255, 0.048);}
    80%  {box-shadow:0 0 18px 18px rgba(255, 255, 255, 0.411);}
    90% {box-shadow:0 0 20px 20px rgba(255, 255, 255, 0.048);}
    100% {box-shadow:0 0 22px 22px rgba(255, 255, 255, 0.048);}
  }