* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;     
    }
  html {
    scroll-behavior: smooth;
    padding-top: 15px;
  }
  body {
  display: flex;
  font-family: Verdana;
  }
  .nav {
    height: 100vh;
    width: 350px;
    position: fixed;
    top: 0;
    left: 0;
    z-index: 999;
    background-color: #3b3a30;
    color: #fff;
    overflow-x:hidden;  
  } 
  .nav header {
    font-size: 32px;
    text-align: center;
    padding: 17px;
    display:flex;
    flex-direction: column;
    align-items: center;
    background-color: #00A1F1;
    color: #111;
    font-weight: 600;
  }
  img {
    width: 100px;
    height: 96px;
    border-radius: 50%;
    text-align: center;
    margin-top: 15px;
    border: 1px solid #818181;
  }
  .nav-link {
    text-decoration: none;
    display: block;
    color: #f1f1f1;
    border-top: 1px solid #818181;
    font-size: 16px;
    padding: 8px 10px;
  }
  .nav-link:hover {
    color: #FBBC05;
  }
  main {
    margin-left: 350px;
    padding: 15px;
  }
  main header {
    font-size: 30px;
    font-weight: bold;
    padding-bottom: 10px;
  }
  hr {
    border: 1px solid #818181;
    margin: 25px 0;
  }
  p {
    padding: 10px 0;
  }
  ul, ol {
    padding-left: 60px;
    margin-bottom: 15px;
  }
  li {
    padding: 2px 0;
  }
  ol li {
    padding-top: 15px;
  }
  .subhead {
    font-size: 24px;
  }
  .inline-code {
    display:inline;
    padding: 0 10px;
  }
  .screenshot {
    max-width: 800px;
    width: 100%;
    height: auto;
    border-radius: 0;
    margin-bottom: 20px;
  }
  code {  background-color: #E8E8E8;
    font-size: x-large;
    display: flex;
    padding: 10px;
    margin: 10px 0;
  }
  .caution {
    border: 1px solid #818181;
    border-left: 3px solid #FBBC05;
    display: flex;
    align-items: center;
    margin: 20px 0;
    padding-bottom: 10px;
  }
  .caution-logo, .info-logo {
    border-radius: 0;
    border: 0;
    padding-bottom: 20px;
  }
  .info {
    border: 1px solid #818181;
    border-left: 3px solid #00A1F1;
    display: flex;
    align-items: center;
    margin: 20px 0;
    padding-bottom: 10px;
  }
  .info-logo{
    width: 70px;
    height: auto;
    padding: 0 10px;
  }
  .caution-container, .info-container {
    padding: 10px;
  }
  .caution-header, .info-header {
    font-weight: bold;
    padding: 4px 0;
  }
  a {
    text-decoration: none;
    font-weight: bold;
  }
  a:hover {
    text-decoration: underline;
  }
  #mobile-navbar {
    display: none;
    height: 15vh;
    width: 100vw;
    position: fixed;
    top: 0;
    left: 0;
    z-index: 999;
    background-color: #3b3a30;
    color: #fff;
    overflow-x:hidden;  
  }
  @media screen and (max-width: 900px), (max-height: 600px){ 
    #mobile-navbar {
      display: flex; 
      flex-wrap: wrap;         
      height: 190px;
    }
    #mobile-navbar header {
      width: 100%;
      text-align: center;
      background-color: #00A1F1;
      color: #111;
      display: flex;
      justify-content: center;
      align-items: center;
      padding-top: 10px;
      font-size: 28px;
    }
    #mobile-navbar header img{
      margin-right: 15px;
    }
    .nav-link-container {
      display: flex;
      flex-wrap: wrap;
      width: 100%;
      justify-content: center;
      padding: 5px;
      align-items: center;
    }
    .nav-link-container span{
      padding: 0 8px;
    }
    .nav-link {      
      font-size: 14px;
      border: none;
      padding: 2px;
      font-weight: normal;
      letter-spacing: 0.5px;
    }
    .nav {
      display:none;
    }
    main {
      margin-left: 0px;
    }
    img {
      width: 50px;
      height: 50px;
      border-radius: 50%;
      text-align: left;
      margin-top: 0px;
      border: 1px solid #818181;
    }
    #Overview {
      margin-top: 160px;
    }
    #Overview, #A_brief_history_lesson, #Opening_a_terminal, #Creating_folders_and_files,
     #Moving_and_manipulating_files, #A_bit_of_plumbing, #The_command_line_and_the_superuser,
     #Hidden_files, #Conclusion {
      scroll-margin-top: 200px;
    }
  }
  @media screen and (max-width: 400px){
    #mobile-navbar {
      height: auto;
    }
    #mobile-navbar header {
      font-size: 22px;
    }
    #Overview {
      margin-top: 230px;
    }
    #Overview, #A_brief_history_lesson, #Opening_a_terminal, #Creating_folders_and_files,
     #Moving_and_manipulating_files, #A_bit_of_plumbing, #The_command_line_and_the_superuser,
     #Hidden_files, #Conclusion {
      scroll-margin-top: 230px;
    }
  }