style.css

body {
              background-color: black;
            }
            div {
            width: 500px;
            height: 100px;

            position: absolute;
            top: 0;
            bottom: 0;
            left: 0;
            right: 0;
            z-index: 2;
            margin: auto;
            }
            #shadowBox {
              display: flex;
              justify-content: center;
              align-items: center;

                background-color: rgba(0, 0, 0, 0);
                /* Fallback color */
                background-color: rgba(0, 0, 0, 0.2);
                /* Black w/opacity/see-through */
            }

            .rainbow {
                text-align: center;
                text-decoration: underline;
                font-size: 62px;
                background-color: white;
                font-family: monospace;
                letter-spacing: 5px;
            }
            .rainbow_text_animated {
                background: linear-gradient(to right, #6666ff, #0099ff , #00ff00, #ff3399, #6666ff);
                -webkit-background-clip: text;
                background-clip: text;
                color: transparent;
                font-size: 202px;
                animation: rainbow_animation 6s ease-in-out infinite;
                background-size: 400% 100%;
                white-space: pre;
            }

            @keyframes rainbow_animation {
                0%,100% {
                    background-position: 0 0;
                }

                50% {
                    background-position: 100% 0;
                }
            }
canvas {
    position: absolute;
    top: 0;
    left: 0;
    z-index: 0;
}
#confettiCanvas {
    position: absolute;
    top: 0;
    left: 0;
    z-index: 1;
}
#fireworkCanvas {
    position: absolute;
    top: 0;
    left: 0;
    z-index: -2;
}