classes.css

/* for collapsible */
/* Style the button that is used to open and close the collapsible content */
.collapsible {
    background-color: black;
    color: rgb(225, 211, 211);
    cursor: pointer;
    /* padding: 10%; */
    width: 100%;
    /* border: none; */
    border-bottom: 5px grey;
    text-align: left;
    outline: none;
    font-size: 15px;
  }
  
  /* Add a background color to the button if it is clicked on (add the .active class with JS), and when you move the mouse over it (hover) */
  .active, .collapsible:hover, .navlink:hover {
    background-color: #ccc;
    color: black;
  }
  
  /* Style the collapsible content. Note: hidden by default */
  .content {
    padding: 18px 18px;
    display: none;
    overflow: hidden;
    background-color: #f1f1f1;
  }

body {
  padding-left: 20%;
  padding-right: 20%;
}