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

html, body {
    width: 100%;
    height: 100%;
    overflow: hidden;
}

body {
    background-color: #000000;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: background-color 0.3s ease;
}

.breathing-box {
    width: 120px;
    height: 120px;
    background-color: #ffffff;
    animation: breathe 16s ease-in-out infinite;
    transition: background-color 0.3s ease;
}

@keyframes breathe {
    /* Initial state - smaller, square */
    0% {
        transform: scale(0.1);
        border-radius: 10%;
    }
    /* Inhale complete - larger, round */
    25% {
        transform: scale(2.6);
        border-radius: 50%;
    }
    /* Hold - stay large and round */
    50% {
        transform: scale(2.6);
        border-radius: 50%;
    }
    /* Exhale complete - smaller, square */
    75% {
        transform: scale(0.1);
        border-radius: 10%;
    }
    /* Hold - stay small and square */
    100% {
        transform: scale(0.1);
        border-radius: 10%;
    }
}