Kolor BS BG

<!-- Bootstrap colors, gradiants and opacity -->
bg-primary
bg-secondary
bg-success
bg-danger
bg-warning
bg-info
bg-light
bg-dark
bg-body
bg-white
bg-transparent

<!-- to add gradiants -->
bg-primary.bg-gradient

<!-- to add opacity -->
style="--bs-bg-opacity: .5;"   or,  bg-opacity-50
Fahim Foysal