The poster raised a very good question. As for whether a web page can apply for a design patent, there is currently no successful precedent.
Chapter 3 of Part 1 of my country’s Patent Examination Guidelines, 6.4.3 Objects not granted design patent protection
(11) Patterns displayed after the product is powered on. For example, the pattern displayed on the dial of an electronic watch, the pattern displayed on the display screen of a mobile phone, the software interface, etc.
So there is currently no successful patent application of this type in our country.