Results: 126
h1 {
    font-size: 7vw;
}
.box {
  width: 50vw;
  height: 100vh;
  background: gray;
  color: white;
}
percentage values are relative to the nearest ancestor element
viewport units are always relative to the browser window
These are alternatives:
background-position: right bottom;
background-position: 100% 100%;
background-position: bottom 0px right 0px;
background-position: right center;
background-position: 100% 50%;
background-position: left top;
background-position: 0% 0%;
background-position: left 0px top 0px
Sprites are usually good for multiple little icons and things like that but no good if you want to repeat something across or down a fluid height content element.
Resize the background image to cover the entire container, even if it has to stretch the image or cut a little bit off one of the edges.
<meta name="viewport" content="width=device-width, initial-scale=1.0">
This tag gives the browser instructions on how to control the page's dimensions and scaling. The line should always be included to create a responsive layout
@media screen and (max-width: 500px) {
    nav ul li {
        width: 50%;
        font-size: 120%;
    }
}
@media screen and (max-width: 620px) {
    nav ul li {
        width: 33%;
    }
}
Results: 126