.btn-tebimgus {
    position: relative;
    border-color: #000 !important;
}

.btn-tebimgus:hover,
.btn-tebimgus:focus,
.btn-tebimgus:active {
    border-color: #0BC3FF !important;
}

.btn-tebimgus::after {
    content: attr(data-error);
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    display: block;
    color: #a94442;
    font-weight: normal;
    text-transform: none;
    text-align: left;
    font-size: small;
    transition: all 0.4s;
    opacity: 0;
}

.btn-tebimgus.show-error::after {
    transition: all 0s;
    opacity: 1;
}