body {
    margin: 0;
    padding: 0;
    font-family: Arial, sans-serif;
    background-color: #000000;
    height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    overflow: hidden;
}

canvas {
    border: none;
    outline: none;
}

#birthday-message {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: rgba(255, 255, 255, 0.69);
    font-size: 10px;
    font-weight: bold;
    z-index: 10;
    opacity: 0;
    transition: opacity 0.5s ease;
    pointer-events: none;
    white-space: nowrap;
}

h1 {
    position: absolute;
    top: 20px;
    left: 50%;
    transform: translateX(-50%);
    color: #333;
    font-size: 2em;
    z-index: 10;
}

#gallery {
    position: relative;
    width: 100vw;
    height: 100vh;
    perspective: 1000px;
    transform-style: preserve-3d;
}

.slide {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-size: contain;
    background-repeat: no-repeat;
    background-position: center;
    background-color: #000000; /* Plain color for extending edges */
    opacity: 1;
    transition: opacity 1s ease;
    transform: rotateY(calc(var(--i) * 72deg)) translateZ(300px);
}