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                <button type="button">


                button {
  background-color: hsl(210, 100%, 50%);
  border: none;
  border-radius: 5px;
  color: white;
  padding: .5rem 1rem;
    Transitions are applied to the original element selector, not
    the pseudo selectors that change the properties.
    The transition shorthand syntax goes as follows: 
    transition: <property> <duration> <timing function>
    Multiple properties to transition can be specified using 
  transition: background-color .1s ease-out,
              transform .1s ease-out,
              box-shadow .1s ease-out;

  Now, we need to change the properties specified in our
  transition attribute above, either through CSS or JavaScript.

button:hover {
  background-color: hsl(210, 100%, 40%);
  box-shadow: 0 5px 3px lightgrey;
  transform: translateY(-1px);

button:active {
  background-color: hsl(210, 100%, 60%);
  box-shadow: none;
  transform: translateY(2px);