How can I center this link
#d1 { width:whatever; margin:0 auto; }
If you don't want to specify a width, you need to use an alternate technique.
Here ya go:
#link-container {
text-align: center;
}
#link {
background: black;
color: white;
display: inline-block;
padding: 10px;
}
<div id="link-container">
<a href="#" id="link">This is my link!</a>
</div>
That what you need?
As simple as:
#d1link {display:block;text-align:center}
text-align:center doesn't work on inline elements. An anchor is an inline element by default.