Try this : (http://jsfiddle.net/TpqVx/)
.left-div {
float: left;
width: 100px;
/*height: 20px;*/
margin-right: 8px;
background-color: linen;
}
.right-div {
margin-left: 108px;
background-color: lime;
}??
<div class="left-div">
</div>
<div class="right-div">
My requirements are <b>[A]</b> Content in the two divs should line up at the top, <b>[B]</b> Long text in right-div should not wrap underneath left-div, and <b>[C]</b> I do not want to specify a width of right-div. I don't want to set the width of right-div because this markup needs to work within different widths.
</div>
<div style='clear:both;'> </div>
Hints :
float:left
in your left-most div only.height
, but anyway...<div 'clear:both'> </div>
after your last div.