.parent-div {
    display: inline-block;
    position: relative;
    overflow: hidden;
}

.parent-div input[type=file] {
    left: 0;
    top: 0;
    opacity: 0;
    position: absolute;
    font-size: 30px;
}

.btn-upload {
    background-color: #fff;
    border: 3px solid #000;
    color: #000;
    padding: 5px 15px;
    border-radius: 10px;
    font-size: 15px;
    font-weight: bold;
}