Recently, I discovered that the kellum method doesn't work as effectively with HTML button elements. Specifically, it does work but requires additional text indent. To sum it up, here is the technique:
text-indent: 100%;
white-space: nowrap;
overflow: hidden;
When using button elements, I notice that I need to increase the text-indent, perhaps to 200% or more. There doesn't seem to be a specific rule, but definitely more than 100%. Why is this the case?