aside.sidebar {
  position: fixed;
  
  height: 100%;
  
  padding: 3.2rem 2.4rem;
  
  background: #15c3d6;
  
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: space-between;
}

aside.sidebar footer button {
  width: 4.8rem;
  height: 4.8rem;
  
  border: none;
  border-radius: 1.6rem;
  
  background: #12afcb;
  
  cursor: pointer;
  
  display: flex;
  align-items: center;
  justify-content: center;
  
  transition: background .2s;
}

aside.sidebar footer button:hover {
  background: #17e6eb;
}

.with-sidebar {
  padding-left: 11rem;
}