There is only the sky above, not the mountains and the atmosphere.
Look up at the red sun and look back at the low white clouds.
2. Translation:
Climbing to the top of the mountain, only the blue sky hangs over the top of Huashan Mountain, surrounded by peaks, and no peak can be equal to Huashan Mountain.
Standing on the peak, you can see how close the red sun is when you look up. In retrospect, you even think the white clouds are very low.