carousel.css

.carousel-control-prev-icon,
.carousel-control-next-icon {
    background-image: none;
}


.carousel-control-prev {
    position: absolute;
    left: -110px;

}

.carousel-control-prev:after {
    content: '';
    display:inline-block;
    width: 1.5rem;
    height: 1.5rem;
    margin-left: 0.5rem;
    border-top: 0.2rem solid #000000;
    border-right: 0.2rem solid #000000;
    transform: rotate(225deg);
}

.carousel-control-next {
    position: absolute;
    left: 880px;
}

.carousel-control-next:after {
    content: '';
    display:inline-block;
    width: 1.5rem;
    height: 1.5rem;
    margin-left: 0.5rem;
    border-top: 0.2rem solid black;
    border-right: 0.2rem solid black;
    transform: rotate(45deg);
}

.carousel-inner .carousel-item {
    background-color: none;
}

/* 1. 더 구체적인 선택자를 사용하여 스타일 적용 */
.carousel-inner .carousel-item:nth-child(1) {
    background-color: #ff0000;
}

.carousel-inner .carousel-item:nth-child(2) {
    background-color: blue;
}

/* 2. !important 키워드 사용 */
.carousel-inner .carousel-item:nth-child(3) {
    background-color: green !important;
}

.carousel-inner .carousel-item:nth-child(4) {
    background-color: gray !important;
}

.carousel-inner .carousel-item:nth-child(5) {
    background-color: orange !important;
}