header {
    background: linear-gradient(to left, transparent 0%, black 20%, black 80%, transparent 100%);
    max-height: 200px;
    height: 20vw;
    min-height: 100px;
    text-align: center;
    flex-shrink: 0;
}

header img {
    min-width: 350px;
    width: 60%;
    max-width:700px;
    align-content: center;
    padding-top: 30px;
}