I am working with a CSS/HTML dropdown that I found online as a starting point. I am tweaking it. When I make the browser smaller (I am using Chrome), there is a gap between the top row and the dropdown menu (see screenshot). Need some help on how to get rid of this gap.
Here is the website I am using as reference.
Thank you for your help!
What it looks like:

What I want:

body,
div,
h1,
h2,
h3,
h4,
h5,
h6,
p,
ul,
ol,
li,
dl,
dt,
dd,
img,
form,
fieldset,
input,
textarea,
blockquote {
margin: 0;
padding: 0;
border: 0;
}
body {
background: #909eab url(bg.png);
font-family: Helvetica, sans-serif;
font-size: 18px;
line-height: 24px;
}
nav {
margin: 100px auto;
text-align: center;
}
nav ul ul {
display: none;
}
nav ul li:hover>ul {
display: block;
}
nav ul {
background: #efefef;
background: linear-gradient(top, #efefef 0%, #bbbbbb 100%);
background: -moz-linear-gradient(top, #efefef 0%, #bbbbbb 100%);
background: -webkit-linear-gradient(top, #efefef 0%, #bbbbbb 100%);
box-shadow: 0px 0px 9px rgba(0, 0, 0, 0.15);
padding: 0 20px;
border-radius: 10px;
list-style: none;
position: relative;
display: inline-table;
}
nav ul:after {
content: "";
clear: both;
display: block;
}
nav ul li {
float: left;
}
nav ul li:hover {
background: #4b545f;
background: linear-gradient(top, #4f5964 0%, #5f6975 40%);
background: -moz-linear-gradient(top, #4f5964 0%, #5f6975 40%);
background: -webkit-linear-gradient(top, #4f5964 0%, #5f6975 40%);
}
nav ul li:hover a {
color: #fff;
}
nav ul li a {
display: block;
padding: 25px 40px;
color: #757575;
text-decoration: none;
}
nav ul ul {
background: #5f6975;
border-radius: 0px;
padding: 0;
position: absolute;
top: 100%;
}
nav ul ul li {
float: none;
border-top: 1px solid #6b727c;
border-bottom: 1px solid #575f6a;
position: relative;
}
nav ul ul li a {
padding: 15px 40px;
color: #fff;
}
nav ul ul li a:hover {
background: #4b545f;
}
nav ul ul ul {
position: absolute;
left: 100%;
top: 0;
}
<nav>
<ul>
<li><a href="#">Home</a></li>
<li><a href="#">Tutorials</a>
<ul>
<li><a href="#">Photoshop</a></li>
<li><a href="#">Illustrator</a></li>
<li><a href="#">Web Design</a>
<ul>
<li><a href="#">HTML</a></li>
<li><a href="#">CSS</a></li>
</ul>
</li>
</ul>
</li>
<li><a href="#">Articles</a>
<ul>
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</li>
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</ul>
</nav>