how do you change the header colours of the website? because no matter what I do it won't change :(

   ♡ ⤑ /  k-groups
. ateez
. svt
. loona
. red velvet
. tbz
. itzy
. monsta x
. nct (all units)
. txt
. iz*one
. like a movie
. shinee
. exo
. skz
. twice
. blackpink
. gidle
. clc
. vav
. weki meki
. astro
. a.c.e
. aweek
. ab6ix
. cravity
. got7 :(((     

       - might be more i can't remember right now - 

       ♡ ⤑ / k-soloists
. dean
. sunmi
. wonho
. somi
. iu
. lee hi
. chungha
. dawn
. hyuna
. jessi
. kim wooseok
. woodz
. kisum

          - might be more i can't remember right now -