This is actually the first comic where I tried specifying colors in CMYK. the CMYK color picker in Clip Studio is kind of baffling. You can use the HSL hue plane, and it will find a corresponding CMYK value, but it will only display the CMYK color if you jiggle the CMYK sliders. This set up actually makes it quite difficult to nail shades of blue.
Another note: the kiosk design is inspired by an old photo in a youtube montage I found:
XD. My brain shorted out after reading the onomatopeias. It makes sense that the Polish windows, and doors talk Polish.