style.css

*, *:before, *:after {
        -moz-box-sizing: border-box;
        -webkit-box-sizing: border-box;
        box-sizing: border-box;
      }

      
      html, body {
        margin: 0;
        padding: 0;
      }
      
      html {
        font-family: 'Sorts Mill Goudy', serif;
        font-size: 10px;
        background-color: white;
      }
      
      body {
        max-width: 700px;
        margin: 0 auto;
        background-color: white;
      }
      
      main {
        padding: 10px; 
      }
      
      p, li {
       font-size: 1.7rem; 
       line-height: 3rem;
      }

      h2 + p, h3 + p {
        text-indent: 1.5rem;
      }
      
      h1, h2, h3 {
       font-family: 'Alfa Slab One', cursive;
      }
      
      hgroup {
        margin: 0; 
      }
      
      h1 {
        text-transform: uppercase;
        text-align: center;
        font-size: 4rem; 
        width: 100%;
        margin: 0;
        padding: 30px 20px;
        color: white;
        background-color: purple;
        letter-spacing: 0.3rem;
        text-shadow: -1px -1px 1px #aaa,
                     0px 4px 1px rgba(0,0,0,0.5),
                     4px 4px 5px rgba(0,0,0,0.7),
                     0px 0px 7px rgba(0,0,0,0.4);
        box-shadow: 0px 5px 10px 3px rgba(0,0,0,0.5);
      }
      
      h2 {
        font-size: 3rem; 
        letter-spacing: 0.2rem;
        color: purple;
      }
      
      hgroup h2 {
        text-align: center; 
        margin-bottom: -1rem;
      }
      
      h3 {
        font-size: 2rem; 
        letter-spacing: 0.2rem;
      }

      a:link {
        font-weight: bold;
      }

      a:hover, a:focus {
        text-decoration: none;
      }

      .note, pre, nav {
        padding: 20px 10px;
        border-radius: 20px;
        background-image: -webkit-linear-gradient(top, rgba(0,0,0,0), rgba(0,0,0,0.2));
        background-image: -moz-linear-gradient(top, rgba(0,0,0,0), rgba(0,0,0,0.2));
        background-image: -ms-linear-gradient(top, rgba(0,0,0,0), rgba(0,0,0,0.2));
        background-image: linear-gradient(to bottom, rgba(0,0,0,0), rgba(0,0,0,0.2));
        font-size: 1.5em;
      }
      
      .note {
        background-color: red;
        background-color: rgba(255,0,0,0.5);
      }

      pre {
        background-color: #eee;
        position: relative;
      }

      p > code, li > code {
        background-color: rgba(0,0,0,0.1);
        color: purple;
        padding: 2px 4px;
      }

      blockquote {
        font-style: italic;
        color: #666;
        position: relative;
      }

      blockquote:before {
        content: "“";
        font-size: 10em;
        position: absolute;
        left: -0.7em;
        top: -0.3em;
        color: purple;
      }

      main img, main iframe {
        display: block;
        max-width: 100%;
        margin: 0 auto;
      }

      .highlight1 {
        background-color: rgba(255,0,0,0.2);
        border: 1px dashed rgba(255,0,0,0.7);
      }

      .highlight2 {
        background-color: rgba(0,150,150,0.2);
        border: 1px dashed rgba(0,150,150,0.7);
      }

      .highlight3 {
        background-color: rgba(0,0,255,0.2);
        border: 1px dashed rgba(0,0,255,0.7);
      }

      .highlight4 {
        background-color: rgba(255,255,0,0.2);
        border: 1px dashed rgba(255,255,0,0.7);
      }
      
      pre span {
        cursor: pointer;
      }

      pre span:before {
        content: attr(data-label);
        opacity: 0;

        padding: 5px 20px 5px 5px;
        border-radius: 5px 0 0 5px;
        color: white;
        font-size: 0.8em;
        box-shadow: -2px 0px 0px black;

        position: absolute;
        left: -24em;

        text-align: right;
        width: 25em;

        -webkit-transform: translateY(-5px);
        -moz-transform: translateY(-5px);
        -ms-transform: translateY(-5px);
        transform: translateY(-5px);
        
        background: #666;
        background: linear-gradient(225deg, transparent 8px, #666 9px) top right no-repeat,
                    linear-gradient(315deg, transparent 8px, #666 9px) bottom right no-repeat;
        background-size: 100% 50%;
      }

      pre span:hover:before, pre span:focus:before {
        opacity: 1;
        transition: 1s all;
      }

      nav p {
        font-size: 0.8em;
        line-height: 1.5;
      }

      nav {
        padding: 1em;
        margin-top: 3em;
        margin-bottom: 1em;
        
        display: -webkit-flex;
        display: -webkit-box;
        display: -ms-flexbox;
        display: -moz-flex;
        display: -moz-box;
        display: flex;

        -webkit-align-items: center;
        -moz-align-items: center;
        -ms-align-items: center;
        align-items: center;

        -webkit-box-align: center;
        -moz-box-align: center;
        -ms-box-align: center;

        -webkit-justify-content: space-between;
        -moz-justify-content: space-between;
        -ms-justify-content: space-between;
        justify-content: space-between;

        -webkit-box-pack: justify;
        -moz-box-pack: justify;
        -ms-box-pack: justify;
      }
      
      @media all and (max-width: 600px) {
        body {
          max-width: none;
          width: 100%;
          
        }
      }