30% vertical keyboard, minimalist beauty [ATmega32a]

Open Source Declaration: CC BY-NC-SA 3.0 Attribution + ShareAlike + Non-Commercial Use.
 
Since using a 40-key inline keyboard, my obsession with minimalist inline keyboards has been unstoppable. Seeing the 30% keyboards created by predecessors, I was immediately captivated.
This project is a wired single-mode keyboard with a simple circuit and easy construction. For a Bluetooth dual-mode keyboard, please use the following project to assemble 5x3 modules side-by-side:
https://oshwhub.com/joba/lan-ya-you-xian-mu-kuai-zu-ge-jian-pan-iqpk-nrf52840
 
I. Design and Construction:
 
Utilizing the ATmega32a onboard main controller, supporting QMK, it is inexpensive and simple.
A dual-board PCB splicing design is a cost-effective option. A borderless design minimizes the overall footprint.
Two design options are available: a positioning board and a base board; one can be made as a single piece for convenience, or two pieces for lower cost.
 
Using my soldering tool, I soldered all the surface-mount components at once. For detailed instructions, see: https://oshwhub.com/iqirtryi/heater-holder.
After confirming the components were soldered correctly, I burned the bootloader and firmware onto the motherboard and debugged it.
 
Then, I used my soldering tool again to connect the positioning plate and base plate made of aluminum substrate: align – clamp – apply a small piece of solder to each joint – heat – melt and wet – done.
 
I then clipped the key switches onto the positioning plate and secured the copper pillars with screws.
 
I placed the soldered circuit board in place and used an N-shaped wire (component leads, copper wires, etc.) to solder the corresponding pads at the joint between the two boards.
I connected it to the computer, shorted each key switch with tweezers, and after testing that all worked properly, I soldered the key switches.
The bottom row has RGB LEDs to display the layer status: normally, the Fn1 and Fn2 keys are lit; pressing different Fn keys displays different colors on the bottom row. 
 
The frame is omitted; a three-layer board is directly fixed with copper pillars, which seems to have a certain structural aesthetic (again, thanks to QIONG).
 
The base plate is made of aluminum substrate with holes for easy programming; 1mm thick anti-slip pads are added.
 
Add the 9.9 RMB keycaps (shipping included), and it's finished! The entire keyboard is inexpensive to make, but its compact and exquisite appearance is still very eye-catching, making it worth taking on business trips with my iPad Air 4.
 
This is another method, where the positioning plate and shell are 3D printed by April, for reference.
 
A cute 15-key keyboard can also be made from a single PCB.