body {
  background-color: #333;
  color: white;
  font-family: "Open Sans", "Arial", "Liberation Sans", sans-serif;
}
h1 {
  font-family: 'Oswald', sans-serif;
  font-weight: 400;
  font-weight: bold;
  margin-bottom: 20px;
}
/* Necessary for positioning the content in the viewport vertical middle */
.outer {
  display: table;
  position: relative;
  width: 100%;
  height: 100%;
}
.middle {
  display: table-cell;
  vertical-align: middle;
}
.inner {
  margin-left: auto;
  margin-right: auto;
  width: 675px;
}
div {
  box-sizing: border-box;
}
#playground-and-stack {
  position: relative;
  width: 680px;
}
#playground {
  display: inline-block;
  width: 450px;
  height: 450px;
  border: 1px solid #666;
}
#stack {
  display: inline-block;
  width: 150px;
  height: 450px;
  margin-left: 70px;
  border: 1px solid #666;
}
.karte {
  border: 1px solid #ccc;
  width: 150px;
  height: 150px;
  position: absolute;
  transition: transform 0.1s, left 0.1s ease, top 0.1s ease;
  float: left;
  background-size: cover;
}
.slow-transitions .karte {
  transition: transform 0.2s, left 0.3s ease, top 0.3s ease;
}
.control-row {
  margin: 10px 0;
}
#controls {
  margin: 20px 0;
  padding: 20px;
  border: 1px solid #666;
}
#speed {
  cursor: pointer;
}
button,
label {
  font-size: 1em;
  font-family: "Open Sans", "Arial", "Liberation Sans", sans-serif;
}
label {
  display: block;
  padding-bottom: 5px;
}
@media screen and (max-width: 800px) {
  #buttons {
    width: 100%;
  }
  .btn {
    width: 33%;
    height: 80px;
  }
  .outer {
    display: block;
    height: auto;
  }
  .middle {
    display: block;
  }
}