Can the two wires of LED ceiling lamp be connected freely?

In order to facilitate construction and maintenance, wires will be marked with color. Generally, the color of AC live wire is mostly red, the zero wire is blue, and the ground wire is yellow and green. DC Brown is the positive pole and the negative pole is blue.

The representative symbol of live wire is l, the representative symbol of zero wire is n, and the representative symbol of ground wire is PE.