<style>

.overlay {
  height: 80%;
  width: 0;
  position: absolute;
  z-index: 1;
  top: 0;
  right: 0;
  background-color: rgb(0,0,0);
  background-color: rgba(0,0,0, 0.9);
  overflow-x: hidden;
  transition: 0.5s;
  background-color: yellow;
}

.overlay-container {padding: 0.5em; position: absolute; top:2em; right:0; background-color: green; width: 40%; height: 100%; }
.overlay-container #navtext 		{width:100%;  height:90%; padding: 1em; background: #f1f1f1;} 

<!--.overlay-content {  position: relative;  top: 1%;  width: 60%;  text-align: center;}-->

.overlay a {  padding: 8px;  text-decoration: none;  font-size: 36px;  color: #818181;  display: block;  transition: 0.3s;}
.overlay a:hover, .overlay a:focus {  color: #f1f1f1;}

.overlay .closebtn {  position: absolute;  top: 2px;  right: 4px;  font-size: 30px;}

@media screen and (max-height: 450px) {
  .overlay a {font-size: 10px}
  .overlay .closebtn {
  font-size: 40px;
  top: 1px;
  right: 3px;
  }
}
</style>