*{
    scroll-behavior: smooth; 
    font-family: Arial, Helvetica, sans-serif;
}
header {
    text-align: left;
    font-size: 20px;
}  
#navbar > header {
    text-align: center;
    line-height: 20px;
}  
#navbar {
    position: fixed;
    top: 0px;
    left: 0px;
    height: 100%;
    min-width: 300px; /*Es mejor hacerlo en px que en porcentajes, se adapta mejor en este caso, pruebalo y mira */
    border-right: solid rgb(230, 230, 230);
}
#navbar li {
    list-style: none;
    position: relative;
    font-size: 18px;
    width: 100%;
    border-top: 1px solid rgb(230, 230, 230);
}
#navbar ul {
    height: 100%;
    overflow-y: auto;
    overflow-x: hidden;
    padding: 0;
}
#navbar a {
    color: black;
    display: block;
    text-decoration: none;
    padding: 10px 10px;
    cursor: pointer;
}
#main-doc {
    position: absolute;
    margin: 25px 25px 0px 325px;
    line-height: 25px;
}
code{
    font-family: monospace;
    display: block;
    text-align: left;
    position: relative;
    word-break: normal;
    word-wrap: normal;
    line-height: 2;
    background-color: #f7f7f7;
    padding: 1em;
    margin: 1em;
    border-radius: 5px;
}
.main-section header{
    font-size: 1.5em;
    font-weight: bold;
    padding: 0.5em 0.5em 0.5em 0em;
}
#fisth2{
    padding-top: 0;
}
@media only screen and (max-width: 750px) {
    #navbar ul {
      width: 100%;
      border-bottom: solid rgb(230, 230, 230);
    }
    #navbar {
      position: absolute;
      width: 100%;
      top: 0;
      padding: 0;
      margin: 0;
      max-height: 130px;
      z-index: 1;
      text-align: center;
    }
    #main-doc {
      position: relative;
      margin: 250px 40px 60px 40px;
    }
  }