How can I make table columns resize when input text grows?

I have a table that fills 100% of its container. The first two columns have a minimum width of 40px, while the last header cell is set to width: 100% so the first columns stay as narrow as their content allows. Each data cell contains a text input. When a user types text that is wider than anything previously entered in a column, can I make the browser recalculate the table layout and expand that column automatically? Ideally, I'd like a CSS-only solution.