body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  background-color: #bbb;
}

/* Add a black background color to the top navigation */
.topnav {
  background-color: #333;
  overflow: hidden;
}

/* Style the links inside the navigation bar */
.topnav a {
  float: left;
  color: #f2f2f2;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
  font-size: 17px;
}

/* Change the color of links on hover */
.topnav a:hover {
  background-color: #ddd;
  color: black;
}

/* Add a color to the active/current link */
.topnav a.active {
  background-color: #4CAF50;
  color: white;
}


.content {
  margin: 20px;
}

input {
  width: 100%;
  margin: 8px 0;
  padding: 12px 3px;
  display: block;
  box-sizing: border-box;
}

button {
  width: 50%;
  padding: 10px;
  margin-top: 10px;
  background-color: #ccc;
}

button:hover {
  background-color: #999;
}