.sombra{
    -webkit-box-shadow: 21px 24px 14px 0px rgba(0,0,0,0.75);
-moz-box-shadow: 21px 24px 14px 0px rgba(0,0,0,0.75);
box-shadow: 21px 24px 14px 0px rgba(0,0,0,0.75);

border: 1px solid #000;
}

ul{
    list-style: none;
}

.responsive-image {
    max-width: 100%;
    height: auto;
    display: block;
    margin: 10px auto; 
    border-radius: 10px;
    margin-bottom: 4rem;
  }