style.css

#navbar {
  position: fixed;
  background-color: rgb(255, 145, 0) !important;
  overflow: -moz-hidden-unscrollable;
  top: 0;
  width: 100%;
  margin-bottom: 5px;
  margin-left: 0%;
  font-weight: bold;
}

#navbarNav a, .sidenav a  {
  color: black;
}

#navbarNav {
  font-family:'Trebuchet MS', 'Lucida Sans Unicode', 'Lucida Grande', 'Lucida Sans', Arial, sans-serif;
  font-weight: bolder;
}

.nav-item .nav-link {
  color: rgb(209, 75, 75);
  margin-left: 5vw;
}

main {
  display: flex;
  flex-wrap: nowrap;
  height: 100vh;
  height: -webkit-fill-available;
  max-height: 100vh;
  margin-top: 60px;
  overflow-x: auto;
  overflow-y: hidden;
}

/* Active/current link */
a.active {
  background-color: #001aff !important;
  color: white !important;
}

/* Links on mouse-over */
.sidenav a:hover:not(.active) {
  background-color: rgb(0, 162, 255);
  color: white !important;
}

/* Page content. The value of the margin-left property should match the value of the sidebar's width property */
.content {
  flex-basis: 80%;
  padding: 1px 16px;
  height: 1000px;
}

.sidenav {
  display: flex;
  flex-shrink: 0;
  flex-direction: column !important;
  flex-basis: 20%;
  background-color: rgba(255, 145, 0, 0.555)
}

.sidenav-ul {
  flex-direction: column;
  margin-bottom: auto;
}

/* On screens that are less than 700px wide, make the sidebar into a topbar */
@media screen and (max-width: 700px) {
  div.content {
    flex-basis: 80%;
  }
}

/* On screens that are less than 400px, display the bar vertically, instead of horizontally */
@media screen and (max-width: 500px) {
  .sidenav {
    flex-basis: 2%;
  }
  .content {
    flex-basis: 98%;
    padding: 1px 5px;
  }
  * {
    font-size: 10px;
  }
  main {
    margin-top: 50px;
  }
}