html,
body {
  height: 100%;
  display: flex;
  flex-direction: column;
}
.main {
  flex-grow: 1;
  border: 1px;
  padding: 0 20px 0 20px;
  margin-bottom: 20px;
  font: 16px/26px Georgia Garamond Serif;
  overflow: auto;
}
.sub {
  display: flex;
  justify-content: center;
  align-items: center;
}
.bottom {
  height: 80px;
}
.button {
  height: 50px;
  width: 200px;
  vertical-align: middle;
  border: 0;
  line-height: 2.5;
  font-size: 1rem;
  text-align: center;
  color: #fff;
  text-shadow: 1px 1px 1px #000;
  border-radius: 10px;
  background-color: rgba(0, 149, 217, 1);
  background-image: linear-gradient(to top left,
  rgba(0, 0, 0, .2),
  rgba(0, 0, 0, .2) 30%,
  rgba(0, 0, 0, 0));
  box-shadow: inset 2px 2px 3px rgba(255, 255, 255, .6),
  inset -2px -2px 3px rgba(0, 0, 0, .6);
}

.button:hover {
  background-color: rgba(136, 206, 250, 1);
}

.button:active {
  box-shadow: inset -2px -2px 3px rgba(255, 255, 255, .6),
  inset 2px 2px 3px rgba(0, 0, 0, .6);
}