.button-container {
    display: flex;
    flex-wrap: wrap;
    width: 100%;
    justify-content: center;
}

.button-container button {
    font-size: 1.15rem;
    font-weight: 700;
    padding: 0.75em 1.5em;
    border: 0;
    border-radius: 100vmax;
    background: linear-gradient(90deg, #ff2220, #ffae00, #ffe100, #85c900, #00b0ff, #8139df, #ff40e1, #ff2220, #ffae00, #ffe100, #85c900, #00b0ff, #8139df, #ff40e1, #ff2220);
    background-size: 2000% 100%;
    cursor: pointer;
    transition: transform 150ms ease-in;
    animation: rainbow-gradient 6s linear infinite;
}

.button-container button:hover {
    transform: scale(1.1);
}

@keyframes rainbow-gradient {
    0% {
        background-position: 0% 50%;
    }
    100% {
        background-position: 100% 50%;
    }
}