Why is temperature in stratosphere and thermosphere increases in altitude?

In the stratosphere, temperature increases with altitude due to the absorption of ultraviolet (UV) radiation by the ozone layer, which warms the air. In the thermosphere, temperature rises significantly with altitude because of the absorption of high-energy solar radiation by sparse gas molecules, causing them to gain energy and move faster. This results in a higher kinetic energy and, consequently, higher temperatures in these layers despite the low density of air.