We do not treat a sold-out size as a prompt to reorder it overnight. Stock is counted on the color and the size together. When a combination is gone, the page says so. Making another run waits until the cloth and the cut are still the ones we want to stand behind.
A kinder wardrobe is mostly a smaller one. Buy the shirt you will put on, care for it, and let it stay. The rest of the work is keeping the line short enough that this is possible.