* {
  box-sizing: border-box;
}

html,
body {
  height: 100vh;
}

body {
  /* https://www.w3schools.com/colors/colors_gradient.asp */
  background: linear-gradient(to bottom, #33ccff 0%, #ff99cc 100%);
  font-family: "Open Sans", sans-serif;
  margin: 0;
}

/* https://stackoverflow.com/questions/19026884/flexbox-center-horizontally-and-vertically  */

/* Author: Michael_B */

.container {
  display: flex; /* establish flex container */
  flex-direction: column; /* make main axis vertical */
  justify-content: center; /* center items vertically, in this case */
  align-items: center; /* center items horizontally, in this case */
  height: 100vh;
}

h1 {
  font-family: "Oswald", sans-serif;
}

#percentage,
#wholenumber,
#result,
#discount {
  border: 1px solid #ccc;
  border-radius: 1em;
  background-color: #f8f8f8;
  box-sizing: border-box;
  display: inline-block;
  margin: 8px 0;
  padding: 10px 10px;
  width: 100%;
}

form {
  width: 300px;
}

button {
  background-color: black;
  border: none;
  border-radius: 1em;
  color: white;
  cursor: pointer;
  display: block;
  margin: 0 auto;
  padding: 10px 10px;
}

#article {
  padding: 3% 10% 0 ;
  background-color: white;
}