CodePen Embed - css dropdown menu

<link href='https://fonts.googleapis.com/css?family=Share+Tech+Mono' rel='stylesheet' type='text/css'>

<ul>
    <a href="#"><li><div class="btn" id="home">HOME
      <ul class="sub-menu2">      
        <a href="">
          <li>Forum</li>
        </a>
        <a href="">
          <li>Gallery</li>
        </a>
        <a href="">
          <li>RSS</li>
        </a>
        <a href="">
          <li>Menu item 4</li>
        </a>
      </ul>
    </div></li></a>
    <a href="#"><li><div class="btn" id="info">INFO
      
      <ul class="sub-menu">     
        <a href="">
          <li>Forum</li>
        </a>
        <a href="">
          <li>Gallery</li>
        </a>
        <a href="">
          <li>RSS</li>
        </a>
        <a href="">
          <li>Menu item 4</li>
        </a>
      </ul>

    </div></li></a>
    <a href="#"><li><div class="btn" id="blog">BLOG

    <ul class="sub-menu">
        <a href="">
          <li>Forum</li>
        </a>
        <a href="">
          <li>Gallery</li>
        </a>
        <a href="">
          <li>RSS</li>
        </a>
        <a href="">
          <li>Menu item 4</li>
        </a>
      </ul>

    </div></li></a>
    <a href="#"><li><div class="btn" id="contact">CONTACT
    
    <ul class="sub-menu2">      
        <a href="">
          <li>Forum</li>
        </a>
        <a href="">
          <li>Gallery</li>
        </a>
        <a href="">
          <li>RSS</li>
        </a>
        <a href="">
          <li>Menu item 4</li>
        </a>
    </ul>

    </div></li></a>
  </ul>

/* https://meyerweb.com/eric/tools/css/reset/ 
   v2.0 | 20110126
   License: none (public domain)
*/

html, body, div, span, applet, object, iframe,
h1, h2, h3, h4, h5, h6, p, blockquote, pre,
a, abbr, acronym, address, big, cite, code,
del, dfn, em, img, ins, kbd, q, s, samp,
small, strike, strong, sub, sup, tt, var,
b, u, i, center,
dl, dt, dd, ol, ul, li,
fieldset, form, label, legend,
table, caption, tbody, tfoot, thead, tr, th, td,
article, aside, canvas, details, embed, 
figure, figcaption, footer, header, hgroup, 
menu, nav, output, ruby, section, summary,
time, mark, audio, video {
  margin: 0;
  padding: 0;
  border: 0;
  font-size: 100%;
  font: inherit;
  vertical-align: baseline;
}
/* HTML5 display-role reset for older browsers */
article, aside, details, figcaption, figure, 
footer, header, hgroup, menu, nav, section {
  display: block;}

body{background: #999;}

ul {
position: relative;
top: 76px;
left: 238px;}

ul li{display: inline-block;}

.btn{
  width: 116px;
  height: 34px;
  line-height: 34px;
  text-align: center;
  font-family: 'Share Tech Mono', sans-serif;
  background-color: #e7e7e7;
  z-index: 99999999999999;

    
  
background: rgb(255,255,255); /* Old browsers */
background: -moz-linear-gradient(top,  rgba(255,255,255,1) 0%, rgba(221,221,221,1) 6%, rgba(204,204,204,1) 94%, rgba(255,255,255,1) 100%); /* FF3.6+ */
background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,rgba(255,255,255,1)), color-stop(6%,rgba(221,221,221,1)), color-stop(94%,rgba(204,204,204,1)), color-stop(100%,rgba(255,255,255,1))); /* Chrome,Safari4+ */
background: -webkit-linear-gradient(top,  rgba(255,255,255,1) 0%,rgba(221,221,221,1) 6%,rgba(204,204,204,1) 94%,rgba(255,255,255,1) 100%); /* Chrome10+,Safari5.1+ */
background: -o-linear-gradient(top,  rgba(255,255,255,1) 0%,rgba(221,221,221,1) 6%,rgba(204,204,204,1) 94%,rgba(255,255,255,1) 100%); /* Opera 11.10+ */
background: -ms-linear-gradient(top,  rgba(255,255,255,1) 0%,rgba(221,221,221,1) 6%,rgba(204,204,204,1) 94%,rgba(255,255,255,1) 100%); /* IE10+ */
background: linear-gradient(to bottom,  rgba(255,255,255,1) 0%,rgba(221,221,221,1) 6%,rgba(204,204,204,1) 94%,rgba(255,255,255,1) 100%); /* W3C */
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#ffffff', endColorstr='#ffffff',GradientType=0 ); /* IE6-9 */

&:hover{
  color: white; 
}
&:hover > a{
  color: white; 
}

&:hover{

    .sub-menu2{
      top: 36px;
      opacity: 1;
    }

    .sub-menu2 a li{
        position: relative;           
      }
    }

.sub-menu2{
    position: absolute;
    opacity: 0;
    left: inherit;
    top: -101px;
    width: inherit;

    -webkit-box-shadow:  -3px -4px 32px rgba(0,0,0,.75);
    -moz-box-shadow:  -3px -4px 32px rgba(0,0,0,.75);
    box-shadow:  -3px -4px 32px rgba(0,0,0,.75);

     -webkit-transition: all 0.3s ease-in-out;
      -moz-transition: all 0.3s ease-in-out;
      -o-transition: all 0.3s ease-in-out;
      transition: all 0.3s ease-in-out; 


    a li{
      width: 100%;

       -webkit-transition: all 0.3s ease-in-out;
      -moz-transition: all 0.3s ease-in-out;
      -o-transition: all 0.3s ease-in-out;
      transition: all 0.3s ease-in-out;
      } 

    a li:hover{ 
      background: white;      

      -webkit-box-shadow: -3px -4px 32px rgba(0,0,0,.75);
      -moz-box-shadow:  -3px -4px 32px rgba(0,0,0,.75);
      box-shadow:  -3px -4px 32px rgba(0,0,0,.75);      
    }
  }

&:hover .sub-menu2{
  
}

.sub-menu a li{
  opacity: 0;
  padding-top: 10px;
  width: 100%;
  line-height: 23px;
  -webkit-transition: all 0.3s ease-in-out;
  -moz-transition: all 0.3s ease-in-out;
  -o-transition: all 0.3s ease-in-out;
  transition: all 0.3s ease-in-out; 

 &:hover{
 background: black;
 color: white;
 opacity: .2;
-webkit-box-shadow: -3px -4px 32px rgba(0,0,0,.75);
-moz-box-shadow: -3px -4px 32px rgba(0,0,0,.75);
box-shadow: -3px -4px 32px rgba(0,0,0,.75);

  }

}



.sub-menu{
  position: absolute;
  margin-top: -176px;
  top: 24px;
  left: 0;
  opacity: 0;
  
  -webkit-transition: all 0.3s ease-in-out;
    -moz-transition: all 0.3s ease-in-out;
    -o-transition: all 0.3s ease-in-out;
    transition: all 0.3s ease-in-out; 

    -webkit-border-bottom-right-radius: 15px;
-webkit-border-bottom-left-radius: 15px;
-moz-border-radius-bottomright: 15px;
-moz-border-radius-bottomleft: 15px;
border-bottom-right-radius: 15px;
border-bottom-left-radius: 15px;
    
}


&:hover .sub-menu{
  margin-top: 6px;
  opacity: 1;
    }

&:hover .sub-menu a li{
  opacity: 1;
  padding-bottom: 10px;
} 

}

#home{
margin-right: -27px;

-webkit-border-top-left-radius: 3px;
-webkit-border-bottom-left-radius: 3px;
-moz-border-radius-topleft: 3px;
-moz-border-radius-bottomleft: 3px;
border-top-left-radius: 3px;
border-bottom-left-radius: 3px;
}


#info{
-webkit-transform: perspective(250px) rotateX(0deg) rotateY(60deg) rotateZ(0deg);
-moz-transform: perspective(250px) rotateX(0deg) rotateY(60deg) rotateZ(0deg);
-o-transform: perspective(250px) rotateX(0deg) rotateY(60deg) rotateZ(0deg);
-ms-transform: perspective(250px) rotateX(0deg) rotateY(60deg) rotateZ(0deg);
transform: perspective(250px) rotateX(0deg) rotateY(60deg) rotateZ(0deg);

-webkit-box-shadow: -3px -4px 32px rgba(0,0,0,.75);
-moz-box-shadow: -3px -4px 32px rgba(0,0,0,.75);
box-shadow: -3px -4px 32px rgba(0,0,0,.75);

margin-right: -73px;
position: relative;
font-size: 27px;
line-height: 29px;
top: 4px;
height: 28px;
z-index: 99999999;


}

#blog{
  -webkit-transform: perspective(250px) rotateX(0deg) rotateY(-60deg) rotateZ(0deg);
-moz-transform: perspective(250px) rotateX(0deg) rotateY(-60deg) rotateZ(0deg);
-o-transform: perspective(250px) rotateX(0deg) rotateY(-60deg) rotateZ(0deg);
-ms-transform: perspective(250px) rotateX(0deg) rotateY(-60deg) rotateZ(0deg);
transform: perspective(250px) rotateX(0deg) rotateY(-60deg) rotateZ(0deg);

-webkit-box-shadow: 3px 4px 32px rgba(0,0,0,.75);
-moz-box-shadow: 3px 4px 32px rgba(0,0,0,.75);
box-shadow: 3px 4px 32px rgba(0,0,0,.75);

margin-right: -26px;
position: relative;
font-size: 27px;
line-height: 29px;
top: 4px;
height: 28px;
z-index: 99999999;
}

#contact{
-webkit-border-top-right-radius: 3px;
-webkit-border-bottom-right-radius: 3px;
-moz-border-radius-topright: 3px;
-moz-border-radius-bottomright: 3px;
border-top-right-radius: 3px;
border-bottom-right-radius: 3px;
}


a{
color: black;
text-decoration: none;}

View Compiled

This Pen is owned by Code Raven on CodePen.

See more by @coderaven98 on CodePen

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.