.stars {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 0;
}

.star {
    position: absolute;
    background-color: white;
    border-radius: 50%;
    animation: twinkle var(--duration) infinite ease-in-out;
    opacity: 0;
}

.star.red {
    background-color: #ff3333;
    box-shadow: 0 0 5px #ff3333;
}

.star.blue {
    background-color: #00f0ff;
    box-shadow: 0 0 5px #00f0ff;
}

@keyframes twinkle {
    0%, 100% { opacity: 0.2; transform: scale(0.5); }
    50% { opacity: 1; transform: scale(1); }
}