nav.thumbnails { 
     width:100vw;
     padding-bottom: 10em;
     background:rgba(12,6,8,0.85);
}

nav.thumbnails ul { 
     list-style-type:none; 
     
     display: flex;
     flex-direction: row;
     flex-wrap: wrap;
     align-items: stretch;

     padding: 1em;
}

nav.thumbnails li { 
     display: inline-block; 
     box-sizing: border-box;

     padding: 1em;

     list-style-type:none;
     line-height: 0;
}
nav.thumbnails li a {
     font-size: 0;
     line-height: 0;
     background-color: red;
}
nav.thumbnails li img {
     border-color: #111111;
     border-style: solid;
     border-width: 1px;
     border-radius: 10px;
     overflow: hidden; 
     width:100%;
} 

@media only screen and (min-width: 480px) {
     nav.thumbnails li {
          width:33.3333%;
     }
}
@media only screen and (min-width: 768px) {
     nav.thumbnails li {
          width:25%;
     }
}
@media only screen and (min-width: 1024px) {
     nav.thumbnails li {
          width:20%;
     }
}
@media only screen and (min-width: 1400px) {
     nav.thumbnails li {
          width:12.5%;
     }
}