* {
  box-sizing: border-box;
}


.column1{
  float: left;
  width: 100%;
  padding: 10px;
  height: auto; 
  
}

.column2{
  float: left;
  width: 70%;
  padding: 10px;
  height: auto; 
  
}


.container {
  overflow: hidden;
  box-shadow: 0px 2px 8px 0px var(--clr-gray-light);
  background-color: transparent;
}

.heading:after{
  content: '';
  display: block;
  width: 100%;
  height: 1px;
  margin-top: 10px;
  background: gray;
  z-index: -2;
  margin-bottom: 20px;
}
  
  .sidebar {
    float: left;
    width: 100%;
    background-color: transparent;
    height: auto;
  }
  
  .sidebar a {
    display: block;
    color: black;
    padding: 5px;
    text-decoration: none;
    margin-top: 5px;
  }
  
   
  .sidebar a.active {
    background-color: #4CAF50;
    color: blue;
  }
  
  .sidebar a:hover:not(.active) {
    background-color: gainsboro;
    color: blue;
  }

  .sidebar a:after{
    content: '';
    display: block;
    width: 100%;
    height: 1px;
    background: gray;
    margin-top: 10px;
    z-index: -2;
  }
  
  @media screen and (max-width: 700px) {
    .sidebar {
      width: 100%;
      height: auto;
      position: relative;
    }
    .sidebar a {float: left;}
    div.content {margin-left: 0;}
  }
  
  @media screen and (max-width: 400px) {
    .sidebar a {
      text-align: center;
      float: none;
    }
  }