(Tumblr Theme) Vertical Dropdown Menu With Submenus - css

Question

I created a vertical dropdown menu with submenus for my custom Tumblr theme. The menu is below a sidebar on the right side.
I was wondering if someone could look over the code for me. I can't tell If there are errors in the code or not. I'm not a coding expert. I did get this code from a tutorial online and made some adjustments to it. I did ask the person who did the tutorial for help but they did not answer me back. I would be thankful if someone can help me with the code or lead me to some good tutorials online.
Here is the working code:
#navsmenu, ul, li, li li {
margin: 0;
padding: 0;
}
#navsmenu {
position: fixed;
margin-top: 16px;
right: 176;
width: 150px;
height: 27px;
}
#navsmenu ul {
line-height: 25px;
}
#navsmenu li {
list-style: none;
position: relative;
background: #79cde2;
}
#navsmenu li li {
list-style: none;
position: relative;
background: #79cde2;
left: 148px;
top: -27px;
}
#navsmenu ul li a {
width: 148px;
height: 25px;
display: block;
text-decoration: none;
text-align: center;
font-family: 'Ubuntu', sans-serif;
color: #ffffff;
border: 1px solid #eee;
}
#navsmenu ul ul {
position: absolute;
visibility: hidden;
top: 27px;
}
#navsmenu ul li:hover ul {
visibility: visible;
}
#navsmenu li:hover {
background-color: #f8a542;
}
#navsmenu ul li:hover ul li a:hover {
background-color: #f8a542;
}
#navsmenu a:hover {
font-weight: bold;
}
<div id="navsmenu">
<ul>
<li>ABOUT</li>
<li>VIDEOS
<ul>
<li>K-POP REVIEWS</li>
<li>K HIP-HOP REVIEWS</li>
<li>SHORT K-POP REVIEWS</li>
<li>SERIOUS K-POP RANTS</li>
<li>K-POP DANCE COVERS</li>
<li>LIFE RANTS</li>
</ul>
</li>
<li>RANDOM K-POP</li>
<li>K-POP EDITS & GRAPHICS</li>
</ul>
</div>