.error-marker {
    position: relative;
    display: inline-block;
}

.error-marker::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background-color: red;
}