Pure JS Implementation with the keyboard control div up and down + zoom out and discoloration

With the keyboard control Div, the red box for the keyboard operation area, you can do the following: control; the background turns green; the background turns yellow; the background turns blue to enlarge or shrink
Use the keyboard to control the Div, the red block for the keyboard operation area, you can do the following:
On: ↑ under: ↓ Left: ← Right: →
Ctrl + 1: The background turns green
Ctrl + 2: The background turns yellow
Ctrl + 3: The background turns blue
Ctrl +↑: Zoom In
Ctrl +↓: Zoom Out

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 Pure JS Implementation with the keyboard control div up and down + zoom out and discoloration