body {
  background-color: #eee;
  font-family: arial;

  -webkit-touch-callout: none;
  -webkit-user-select: none;
  -khtml-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;

  margin: 0;
}

.timerButton {
  display: inline-block;
  border-radius: 50%;
  background-color: #8cf;
  border: 1px solid black;
  transition: background-color 0.3s, color 0.3s;
}

.timerButton:hover {
  cursor: pointer;
}

.timerButton.timerActive {
  background-color: #37a;
  color: white;
}

.timerButton > div {
  padding-top: 50%;
  line-height: 1;
  text-align: center;
  width: 100%;
  margin-top: -0.5em;
}

#header, #footer {
  width: 100%;
  box-sizing: border-box;
  text-align: center;
  background-color: #777;
  color: white;
  padding: 0.3em;
}

#footer {
  position: fixed;
  bottom: 0;
}