Denim vests are actually very well matched and can be worn in different styles:

1, denim vest+plaid shirt+loose casual pants (canvas, velvet, denim) = American casual style

2, denim vest+chiffon floral skirt+retro Brock shoes = British style is small and fresh

3, denim vest+monochrome shirt+slim pants = neutral and capable

4, denim vest+cotton soft top+long skirt = literary retro style

5, denim vest+arbitrary T-shirt+white worn trousers = mix and match