CSS not filling entire width - html

Question

I have a navigation tab which is only taking up half of the width which I require, I need it to take up 100% width however it does not. I have looked at around this site and google could not get it working like I want it. IThe navigation ie the black background should take up 100% of the width however it does not. any ideas.
nav ul ul {
display: none;
}
nav ul li:hover > ul {
display: block;
}
nav ul {
background: #1e1d1d;
background: linear-gradient(top, #1e1d1d 0%, #bbbbbb 100%);
background: -moz-linear-gradient(top, #1e1d1d 0%, #bbbbbb 100%);
background: -webkit-linear-gradient(top, #1e1d1d 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: #f7f7f7;
background: linear-gradient(top, #f7f7f7 0%, #5f6975 40%);
background: -moz-linear-gradient(top, #f7f7f7 0%, #5f6975 40%);
background: -webkit-linear-gradient(top, #f7f7f7 0%,#5f6975 40%);
}
nav ul li:hover a {
color: #ff0000;
}
nav ul li a {
display: block; padding: 25px 40px;
color: #f7f7f7; text-decoration: none;
}
nav ul ul {
background: #f7f7f7; border-radius: 0px; padding: 0;
position: absolute; top: 100%;
}
nav ul ul li {
float: none;
position: relative;
}
nav ul ul li a {
padding: 15px 40px;
}
nav ul ul li a:hover {
background: #888484;
color: #ff0000;
}
nav ul ul ul {
position: absolute; left: 100%; top:0;
}
<nav>
<ul>
<li>Basin & Sinks</li>
<li>Showers
<ul>
<li>Shower Trays</li>
<li>Shower Glass
<ul>
<li>Frosted</li>
<li>Clear</li>
</ul>
</li>
</ul>
</li>
<li>Bathroom Accessories
<ul>
<li>Plugs</li>
<li>Toilet Paper</li>
</ul>
</li>
<li>Toilets</li>
</ul>
</nav>
https://jsfiddle.net/1nzot5rq/1/
have tried several links and have tried width: 100%, max-width: 100%; however I have had no luck.

Answer 1

Just add width: 100%; box-sizing: border-box; to nav ul like this: https://jsfiddle.net/d8ch5qer/
nav ul ul {
display: none;
}
nav ul li:hover > ul {
display: block;
}
nav ul {
background: #1e1d1d;
background: linear-gradient(top, #1e1d1d 0%, #bbbbbb 100%);
background: -moz-linear-gradient(top, #1e1d1d 0%, #bbbbbb 100%);
background: -webkit-linear-gradient(top, #1e1d1d 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;
width: 100%;
box-sizing: border-box;
}
nav ul:after {
content: "";
clear: both;
display: block;
}
nav ul li {
float: left;
}
nav ul li:hover {
background: #f7f7f7;
background: linear-gradient(top, #f7f7f7 0%, #5f6975 40%);
background: -moz-linear-gradient(top, #f7f7f7 0%, #5f6975 40%);
background: -webkit-linear-gradient(top, #f7f7f7 0%, #5f6975 40%);
}
nav ul li:hover a {
color: #ff0000;
}
nav ul li a {
display: block;
padding: 25px 40px;
color: #f7f7f7;
text-decoration: none;
}
nav ul ul {
background: #f7f7f7;
border-radius: 0px;
padding: 0;
position: absolute;
top: 100%;
}
nav ul ul li {
float: none;
position: relative;
}
nav ul ul li a {
padding: 15px 40px;
}
nav ul ul li a:hover {
background: #888484;
color: #ff0000;
}
nav ul ul ul {
position: absolute;
left: 100%;
top: 0;
}
<nav>
<ul>
<li>Basin & Sinks</li>
<li>Showers
<ul>
<li>Shower Trays</li>
<li>Shower Glass
<ul>
<li>Frosted</li>
<li>Clear</li>
</ul>
</li>
</ul>
</li>
<li>Bathroom Accessories
<ul>
<li>Plugs</li>
<li>Toilet Paper</li>
</ul>
</li>
<li>Toilets</li>
</ul>
</nav>

Answer 2

Add:
nav ul {
width: 100%;
display:block;
}
But even with that you will have problem managing you columns to fit all width. You can use JS to calculate each width or use display: table for nav ul and display: table-cell for you ul li's

Answer 3

If you're looking on Chrome, Chrome adds 40px of padding as follows to <ul>'s:
-webkit-padding-start: 40px;
This is making the <ul> extend over the width you define.
There's 2 ways of overcoming this:
1. Remove all padding, including browser defaults
https://jsfiddle.net/pzod450b/1/
Simply add -webkit-padding-start: 0. On top of that, you've also added 20px of padding either side of the <ul>, remove this
CSS:
nav ul {
background: #1e1d1d;
background: linear-gradient(top, #1e1d1d 0%, #bbbbbb 100%);
background: -moz-linear-gradient(top, #1e1d1d 0%, #bbbbbb 100%);
background: -webkit-linear-gradient(top, #1e1d1d 0%,#bbbbbb 100%);
box-shadow: 0px 0px 9px rgba(0,0,0,0.15);
border-radius: 10px;
list-style: none;
position: relative;
display: inline-table;
width: 100%;
}
2. Use box-sizing: border-box
Using this method will ensure that the browser calculates all padding/border applied to an element within it's final width:
https://jsfiddle.net/u1vzag3b/
nav ul {
background: #1e1d1d;
background: linear-gradient(top, #1e1d1d 0%, #bbbbbb 100%);
background: -moz-linear-gradient(top, #1e1d1d 0%, #bbbbbb 100%);
background: -webkit-linear-gradient(top, #1e1d1d 0%,#bbbbbb 100%);
box-shadow: 0px 0px 9px rgba(0,0,0,0.15);
border-radius: 10px;
list-style: none;
position: relative;
display: inline-table;
width: 100%;
box-sizing: border-box;
}
You'll notice in both cases, you should add width: 100% to nav ul.