header{
    position: relative;
    height: 250px;
}
header img{
    position: absolute;
    top: 50%; left: 50%;
    transform: translate(-50%,-50%);
    object-fit: cover;
    display: block;
    width: 100%; height: 100%;
}
.container-small{
    max-width: 350px;
}
.input-group-text.basic-addon{
    min-width: 50px;
    text-align: center;
    display: inline-block;
}