body {
   padding: 0.5em;
   background-color: #000;
   font: normal 1em / 1.5  verdana, arial, helvetica, sans-serif;
 }
h1 {
   font-size: 1.25em;
   margin: 0 0.5em;
   text-align: center;
   color: #fff;  
 }
#floor-tiling {
   display: flex;
   align-items: center;
 }
#floor-tiling div { 
   width: 50%;
   color: #fff;
   text-align: center;
 }
#floor-tiling p {
   font-size: 1.1em;
   margin-right: 1em;
 }
 #go-back {
   display: block;
   padding: 0.25em;
   margin: 2em auto;
   border: 2px solid #ffd700;
   font-size: 1.25em;
   cursor: pointer;
 }
video {
   display: block;
   width: 100%;
   max-width: 18em;
   height: auto;
   border: 1px solid #ffd700;
   margin: auto;
   cursor: pointer;
}
#normal-video {
   max-width: 30em;
}