#main-title {
    color: blue;
    background-color: hsl(210, 100%, 50%);
}

.intro-paragraph {
    color: #8A2BE2; rgba(0, 128, 0, 0.3)
}

#color-box {
    color: coral;
    background-color: yellow;
}

div+p {
    background-color: rgba(0, 128, 0, 0.3);
}