Css select all but first tr doesn't work - html

Question

Here's the fiddle:
https://jsfiddle.net/80mek2sL/1/
I want to select all but the first tr and apply:
border-top: 1px grey solid;
Then I want to select all first td's but not the first td of the first tr (= ignore first tr) and apply
border-right: 1px grey dotted;
(I totally dont care about compatibility with prehistorical Web browsers, I just want it to work on nowadays Web browsers)
What I dont get (that's why I'm lost actually) is that immediate selector table > tr doesn't select tr (otherwise I would have solved my problem)

Answer 1

Your selector is working. The problem is that tr's don't have a border. You need to apply it the td within...
#cheatsheet tr:not(:first-child) td {
border-top:1px grey solid;
background-color: #EF0;
}
Updated Fiddle
#cheatsheet td {
margin:2px;
padding:2px
}
#cheatsheet tr td:first-child {
padding-left:10%;
width:30%;
}
#cheatsheet thead {
background-color: #EFE;
}
#cheatsheet h3 {
text-align: center;
}
table#cheatsheet {
border:1px black solid;
margin:2px; padding:2px;
border-right:1px grey solid;
width:100%;
}
#cheatsheet tr:not(:first-child) td {
border-top:1px grey solid;
background-color: #EF0;
}
<h1>Vim</h1>
<table id="cheatsheet">
<thead><tr>
<td colspan="2"><h3>aa</h3></td>
</tr></thead>
<tr>
<td><code class="prettyprint lang-sh">:split</code></td>
<td style="width:auto">bb</td>
</tr>
<tr>
<td><code class="prettyprint lang-sh">:vsplit</code></td>
<td style="width:auto">split vertical</td>
</tr>
</table>
On another note, the reason table > tr doesn't work is because tr's are not an immediate descendant of table in the rendered HTML. If you use your browsers element inspector you will see that thead and tbody elements are automatically inserted for you
EDIT
After the comment below all you need to do is this...
#cheatsheet tbody td {
border-top:1px grey solid;
background-color: #EF0;
}
ie. target the td within tbody only,
Updated Fiddle

Answer 2

check fiddle :https://jsfiddle.net/80mek2sL/6/
nth-child(n+2) selector helps to select any number of child. in following example I am selecting row from ahead of second child.
#cheatsheet tr:nth-child(n+2) td {
border-top:1px grey solid;
background-color: #EF0;
}
You can also play aorund (n + *) and check the result to better understand the nth-child selector
note: you can not put border property to <tr> so you will need to
assign it to <td>
HTML
<table id="cheatsheet">
<thead>
<tr>
<td colspan="2">
<h3>aa</h3>
</td>
</tr>
</thead>
<tr>
<td><code class="prettyprint lang-sh">:split</code>
</td>
<td style="width:auto">bb</td>
</tr>
<tr>
<td><code class="prettyprint lang-sh">:vsplit</code>
</td>
<td style="width:auto">split vertical</td>
</tr>
<tr>
<td><code class="prettyprint lang-sh">:vsplit</code>
</td>
<td style="width:auto">split vertical</td>
</tr>
<tr>
<td><code class="prettyprint lang-sh">:vsplit</code>
</td>
<td style="width:auto">split vertical</td>
</tr>
</table>
CSS
#cheatsheet td {
margin:2px;
padding:2px
}
#cheatsheet tr td:first-child {
padding-left:10%;
width:30%;
}
#cheatsheet thead {
background-color: #EFE;
}
#cheatsheet h3 {
text-align: center;
}
table#cheatsheet {
border:1px black solid;
margin:2px;
padding:2px;
border-right:1px grey solid;
width:100%;
}
#cheatsheet tr:nth-child(n+2) td {
border-top:1px grey solid;
background-color: #EF0;
}