A 1- or 2-pixel space is introduced between rows in various situation described below, which becomes obvious when using coloured backgrounds. All three examples have block-display in common.

1) list <li>

.even {
background-color: #444444;
display: block;
}

<ul>
<li><span class="S1510 odd">LSE          open 08:00 close 16:30 </span></li>
<li><span class="S1510 even">NYSE         open 14:30 close 21:00 </span></li>
</ul>

If you remove "display: block", the space disappears.


2) <div>

.even {
padding: 3px 0 3px 3px;
background-color: #444444;
display: block;
}


<div class="S1510 odd">LSE          open 08:00 close 16:30 </div>
<div class="S1510 even">NYSE         open 14:30 close 21:00 </div>

3) <span><br>

.even {
padding: 3px 0 3px 3px;
background-color: #444444;
display: block;
}

<span class="S1510 odd">LSE          open 08:00 close 16:30 </span><br>
<span class="S1510 even">NYSE         open 14:30 close 21:00 </span><br>

If you remove "display: block", the space disappears.
Firefox displays a big space between rows unless you take <br> out.


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I shall add HTML and screenshots for all three examples.