Validation Summary CSS not rendered

.validation-summary-errors {
    position: relative;
    padding: 1rem;
    color: #C2001B;
    background-color: #FFBCC6;
    border: #FFBCC6;
    border-radius: 0.375rem;
}

.validation-summary-errors span{
    font-weight: bold;
}

.validation-summary-errors ul {
    margin: 0;
}

.field-validation-error {
    color: #b94a48;
}

.field-validation-valid {
    display: none;
}

.form-control.input-validation-error {
    border: 1px solid #b94a48;
    border-color: #B94A48 !important;
}

input[type="checkbox"].input-validation-error {
    border: 0 none;
}

.validation-summary-valid {
    display: none;
}