Hi,
A homemade single layer layout.
Just from EMC view you should go for a double sided layout.
With this layout:
* I´d reduce the wire width from 0.6mm to 0.4mm or less.
* I´d increase the isolation to at least 0.25 mm
* route all air wires.
* use the DRC, but first set your DRC values.
It seems to be a LED display. It needs a lot of current. Thus the microcontroller may see varying supply voltage (caused by voltage drop). This may cause instability in clock frequency.
Check: doesn´t the XTAL need some capacitors?
I´m no friend of copper pour at all. And especially as GND. It pretends to be stable and reliable, but instead it causes additional inductance. Your GND loops may cause problems when HF sources like cellular phone, WIFI, Bluetooth is near your PCB. --> If possible make the TOP layer a solid GND plane without other traces.
I assume you don´t need to pass an EMC test. It is about impossible with this layout.
Klaus