#billing-phone.phone-error {
    border: 2px solid #e60000 !important;
    background-color: #fff5f5 !important;
}

.wc-block-components-address-form__phone label {
    color: #e60000 !important;
    font-weight: bold;
}

@keyframes shake {
    0% { transform: translateX(0); }
    25% { transform: translateX(-5px); }
    50% { transform: translateX(5px); }
    75% { transform: translateX(-5px); }
    100% { transform: translateX(0); }
}

.shake {
    animation: shake 0.4s;
}