.side-bar {
  width: 20%;
  float: left;
}

.collapsed {
  width: 70px;
}

.button-container {
  position: relative;
  z-index: 100;
}

.button-container > button {
  position: fixed;
  top: calc(100vh - 35px);
  left: -10px;
  background: #424242;
  border: 1px solid #dadada;
  box-shadow: #ffd740 0 0 3px;
}