body {
  width: 290px;
  color: #4d4e53;
  background-color: #fff;
  font-family: Times new roman, sans-serif;
  line-height: 1.6;
}

#navbar {
  position: fixed;
  top: 0px;
  left: 0px;
  width: 310px;
  height: 100%;
  border-style: solid;
  border-width: 1px;
  border-color: green;
  }

header {
  color: green;
  margin: 15px;
  text-align: center;
  font-size: 1.2em;
  font-weight: thin;
}

span {
  color: red;
  font-size: 0.5em;
}

#main-doc header {
text-align: left;
margin: 0px;
}

#navbar ul {
  height: 100%;
  padding: 0;
  overflow-y: auto;
  overflow-x: hidden;
}

#navbar li {
  color: #aabbcc;
  border-top: 1px solid;
  list-style: none;
  position: relative;
  width: 100%;
}

#navbar a {
  padding: 10px 30px;
  color: black;
  text-decoration: none;
  cursor: pointer;
  display: block;
}

#main-doc {
  position: absolute;
  margin-left: 310px;
  padding: 50px;
  margin-bottom: 100px;
}

section article {
  color: #4d4e53;
  margin: 15px;
  font-size: 1.0em;
}

section li {
  margin: 10px 0px 0px 30px;
}

code {
  display: block;
  text-align: left;
  white-space: pre-line;
  position: relative;
  word-break: normal;
  word-wrap: normal;
  line-height: 2.5;
  background-color: #c7c7c7;
  padding: 15px;
  margin: 20px;
  border-radius: 7px;
}

/*smart-device*/

@media only screen and (max-width: 810px) {
  #navbar ul {
    border: 1px solid;
    height: 200px;
  }

  #navbar {
    background-color: white;
    position: absolute;
    top: 0;
    padding: 0;
    margin: 0;
    width: 100%;
    max-height: 275px;
    border: none;
    z-index: 1;
    border-bottom: 2px solid;
  } 

  #main-doc {
    position: fixed;
    margin-left: 0px;
    margin-top: 270px;
  }
  span {
  color: red;
  font-size: 0.5em;
  }
}

@media only screen and (max-width: 400px) {
 #main-doc {
    margin-left: -10px;
  }

  code {
    margin-left: -10px;
    width: 100%;
    padding: 15px;
    padding-left: 10px;
    padding-right: 45px;
    min-width: 233px;
  }
    span {
   color: red;
   font-size: 0.5em;
  }
}