CSS: how to remove the top-gap for sub-menus? - html

Question

I've a code snippet of a vertical fly-out-menu and would like to avoid the top gap of the sub-menus.
I made some progress with float, position and top but got lost in some dirty code.
That's the desired result:
What's a good/best/common practice to solve the problem? Thanks in advance!
/* Define the body style */
body {
font-family:Arial;
font-size:12px;
}
/* We remove the margin, padding, and list style of UL and LI components */
#menuwrapper ul, #menuwrapper ul li{
margin:0;
padding:0;
list-style:none;
}
/* We apply background color and border bottom white and width to 150px */
#menuwrapper ul li{
background-color:#7f95db;
border-bottom:solid 1px white;
width:150px;
cursor:pointer;
}
/* We apply the background hover color when user hover the mouse over of the li component */
#menuwrapper ul li:hover{
background-color:#6679e9;
position:relative;
}
/* We apply the link style */
#menuwrapper ul li a{
padding:5px 15px;
color:#ffffff;
display:inline-block;
text-decoration:none;
}
/**** SECOND LEVEL MENU ****/
/* We make the position to absolute for flyout menu and hidden the ul until the user hover the parent li item */
#menuwrapper ul li ul{
position:absolute;
display:none;
}
/* When user has hovered the li item, we show the ul list by applying display:block, note: 150px is the individual menu width. */
#menuwrapper ul li:hover ul{
left:150px;
top:0px;
display:block;
}
/* we apply different background color to 2nd level menu items*/
#menuwrapper ul li ul li{
background-color:#cae25a;
}
/* We change the background color for the level 2 submenu when hovering the menu */
#menuwrapper ul li:hover ul li:hover{
background-color:#b1b536;
}
/* We style the color of level 2 links */
#menuwrapper ul li ul li a{
color:#454444;
display:inline-block;
width:120px;
}
/**** THIRD LEVEL MENU ****/
/* We need to hide the 3rd menu, when hovering the first level menu */
#menuwrapper ul li:hover ul li ul{
position:absolute;
display:none;
}
/* We show the third level menu only when they hover the second level menu parent */
#menuwrapper ul li:hover ul li:hover ul{
display:block;
left:150px;
top:0;
}
/* We change the background color for the level 3 submenu*/
#menuwrapper ul li:hover ul li:hover ul li{
background:#86d3fa;
}
/* We change the background color for the level 3 submenu when hovering the menu */
#menuwrapper ul li:hover ul li:hover ul li:hover{
background:#358ebc;
}
/* We change the level 3 link color */
#menuwrapper ul li:hover ul li:hover ul li a{
color:#ffffff;
}
/* Clear float */
.clear{
clear:both;
}
<div id="menuwrapper">
<ul>
<li>Home</li>
<li>Products
<ul>
<li>Product 1
<ul>
<li>Sub Product 1</li>
<li>Sub Product 2</li>
<li>Sub Product 3</li>
</ul>
</li>
<li>Product 2</li>
<li>Product 3</li>
</ul>
</li>
<li>About Us
<ul>
<li>Faqs</li>
<li>Contact Us</li>
<li>Where are we?</li>
</ul>
</li>
<li>Help
</ul>
</div>

Answer 1

How does this look:
https://jsfiddle.net/tobyl/um02Loxc/1/
Relevant code:
#menuwrapper ul {
position: relative;
}
And:
/* We apply the background hover color when user hover the mouse over of the li component */
#menuwrapper ul li:hover{
background-color:#6679e9;
}

Answer 2

say body margin is 0
body{
margin:0;
}