body {
  background-color: white;
  margin: 0;
  display: flex;
  height: 100vh;
  overflow: hidden;
}

.sidebar {
  width: 15vw;
  min-width: 150px;
  background-color: gray;
  overflow-y: auto; 
}

iframe {
  flex-grow: 1;
  height: 100%;
}

ul {
  list-style-type: none;
  margin: 0px;
  padding: 0px;
}

li a {
  display: block;
  color: black;
  padding: 12px 16px;
  text-decoration: none;
  background-color: gray;
  border-bottom: 1px solid #777;
}

li a:hover {
  background-color: #555555;
  color: white;
}

@media (max-width: 768px) {
  body {
    flex-direction: column;
  }

  .sidebar {
    width: 100%;
    min-height: auto;
  }

  ul {
    display: flex;
  }

  li {
    flex: 1;
    text-align: center;
  }

  li a {
    border-bottom: none;
    border-right: 1px solid #777;
    padding: 10px 5px;
    font-size: 14px;
  }

  li:last-child a {
    border-right: none;
  }
}