Responsive Design with CSS Media Screens

A memo about sample CSS code examples for implementing responsive screens using CSS media screens. Use code like “@media screen and (min-width: 800px)” as shown below.

@media screen and (min-width: 800px) {
  #yuishelp {
        position: absolute; right: 8em;  top: 80px;
  }
}

@media screen and (max-width: 800px) {
  #yuishelp {
        display: none ;
  }
}