How to set pages and label sizes on WeChat public platform

I made a website that deals with business applications, there are three entrances, corresponding to three businesses respectively.
The portal is placed on the work platform, which means that the user only opens the site.
Now the problem is that I get the size of the browser window via JS to set the height&width of my web page label, but when I click on the input box, the input box becomes larger.

Reply content:

I made a website that deals with business applications, there are three entrances, corresponding to three businesses respectively.
The portal is placed on the work platform, which means that the user only opens the site.
Now the problem is that I get the size of the browser window via JS to set the height&width of my web page label, but when I click on the input box, the input box becomes larger.

In fact, you can use the adaptive, all use 20% such as the percentage of the way to achieve positioning.

CSS Height Adaptive

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