body {
  color: black;
  background: white;
  text-align: center;
  font-family: Helvetica, Arial, sans-serif;
}
.section {
  margin-bottom: 1em;
  border: 1px solid grey;
  border-radius: 15px;
  padding: 5px;
  background: #f7f7f7;
}
hr {
  margin-bottom: 1em;
}
a {
  color: #ff0000;
}

/* slider checkboxes
   https://www.w3schools.com/howto/tryit.asp?filename=tryhow_css_switch
*/
.switch {
  position: relative;
  display: inline-block;
  width: 46px;
  height: 26px;
}

.switch input { 
  opacity: 0;
  width: 0;
  height: 0;
}

.slider {
  position: absolute;
  cursor: pointer;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: #ccc;
  -webkit-transition: .4s;
  transition: .4s;
}

.slider:before {
  position: absolute;
  content: "";
  height: 20px;
  width: 20px;
  left: 3px;
  bottom: 3px;
  background-color: white;
  -webkit-transition: .4s;
  transition: .4s;
}

input:checked + .slider {
  background-color: #2196F3;
}

input:focus + .slider {
  box-shadow: 0 0 1px #2196F3;
}

input:checked + .slider:before {
  -webkit-transform: translateX(20px);
  -ms-transform: translateX(20px);
  transform: translateX(20px);
}

/* Rounded sliders */
.slider.round {
  border-radius: 20px;
}

.slider.round:before {
  border-radius: 50%;
}