Final answer:
Blunt bangs are not designed for all hair lengths because they require a certain length to lay flat and straight across the forehead, which is not adaptable to very short hair.
Step-by-step explanation:
The bang style that is generally NOT designed for all hair lengths is blunt bangs. Blunt bangs usually require a certain amount of hair length to lay flat and straight across the forehead, and they are cut in a straight line. They are not as versatile as other bang styles like side-swept, wispy, or layered bangs, which can be adapted to suit different hair lengths and textures.
Blunt bangs do not lend themselves well to very short hair as there might not be enough length to create the straight-across style they require, making them less compatible with varied hair lengths compared to the other options listed.