Complex sentence: The flag's background is white, a traditional Korean color, common to the daily attire of 19th-century Koreans and still used in traditional Korean garments such as the hanbok.
Split into simpler sentences: The flag's background is white, a traditional Korean color. White was common to the daily attire of 19th-century Koreans, and it still appears in contemporary versions of traditional Korean garments, such as the hanbok.