style.css

@import url('https://fonts.googleapis.com/css2?family=Noto+Sans&display=swap');
*
{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Noto Sans', sans-serif;
}

body {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: #0e1538;
}

.box {
    position: relative;
    width: 300px;
    height: 300px;
    display: flex;
    justify-content: center;
    align-items: center;
    background: rgba(0, 0, 0, 0.5);
    overflow: hidden;
    border-radius: 20px;
    margin: 20px;
}

.box::before {
    content: '';
    position: absolute;
    width: 150px;
    height: 140%;
    background: linear-gradient(#00ccff, #d400d4);
    animation: animate 4s linear infinite;
}

.box::after {
    content: '';
    position: absolute;
    inset: 4px;
    background: #0e1538;
    border-radius: 16px;
}
@keyframes animate {
    0%
    {
        transform: rotate(0deg);
    }
    100%
    {
        transform: rotate(360deg);
    }
}

.box h2 {
    position: relative;
    color: #fff;
    font-size: 2em;
    z-index: 10;
}