* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    background-color: #121212; 
    margin: 0;
}

.cube {
    width: 200px;
    height: 200px;
    position: relative;
    transform-style: preserve-3d;
    animation: rotate 5s infinite linear;
}

.face {
    position: absolute;
    width: 200px;
    height: 200px;
    background-color: #333;
    background-image: 
        linear-gradient(0deg, #888 1px, transparent 1px), 
        linear-gradient(90deg, #888 1px, transparent 1px); 
    background-size: 20px 20px; 
}

.front  { transform: rotateY(0deg) translateZ(100px); }
.back   { transform: rotateY(180deg) translateZ(100px); }
.left   { transform: rotateY(-90deg) translateZ(100px); }
.right  { transform: rotateY(90deg) translateZ(100px); }
.top    { transform: rotateX(90deg) translateZ(100px); }
.bottom { transform: rotateX(-90deg) translateZ(100px); }

@keyframes rotate {
    from { transform: rotateX(0deg) rotateY(0deg); }
    to { transform: rotateX(360deg) rotateY(360deg); }
}

footer {
    position: absolute;
    bottom: 0;
    padding: 10px;
    color: #888;
    font-size: 0.9em;
    text-align: center;
    width: 100%;
    font-family: Arial, Helvetica, sans-serif;
    font-size: smaller;
}