body {
    padding: 0;
    margin: 0;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

#challenge13 ul {
    list-style-type: none;
    display: flex;
}

#challenge13 ul li {
    font-size: 45px;
    margin: 0 5px;
    color: #333;
    font-family: Arial, sans-serif;
    animation: letter-loader-animation 5s linear infinite;
}

#challenge13 ul li:nth-child(1) {
    animation-delay: 0s;
}

#challenge13 ul li:nth-child(1) {
    animation-delay: 0.2s;
}

#challenge13 ul li:nth-child(2) {
    animation-delay: 0.4s;
}

#challenge13 ul li:nth-child(4) {
    animation-delay: 0.6s;
}

#challenge13 ul li:nth-child(5) {
    animation-delay: 0.8s;
}

#challenge13 ul li:nth-child(6) {
    animation-delay: 1.0s;
}

#challenge13 ul li:nth-child(7) {
    animation-delay: 1.2s;
}

@keyframes letter-loader-animation {
    0% {
        color: #00b3ff;
        transform: translate(-50px, 0);
        letter-spacing: 20px;
        opacity: 0;
    }
    10% {
        opacity: 1;
    }
    50% {
        letter-spacing: -20px;
        opacity: 1;
    }
    100% {
        color: #ff0044;
        transform: translate(50px, 0px);
        letter-spacing: 20px;
        opacity: 0;
    }
}