/* ── FTF Engineering background ──────────────────────────────────────────── */
html {
    background: rgba(0,0,0,.4);
    box-shadow: inset 0 0 60px 30px rgba(0,0,0,.45);
}
.background {
    width: 100%;
    height: 100%;
    top: 0;
    display: block;
    position: fixed;
    z-index: 0;
    background:
        linear-gradient(135deg, #708090 22px, #d9ecff 22px, #d9ecff 24px, transparent 24px, transparent 67px, #d9ecff 67px, #d9ecff 69px, transparent 69px),
        linear-gradient(225deg, #708090 22px, #d9ecff 22px, #d9ecff 24px, transparent 24px, transparent 67px, #d9ecff 67px, #d9ecff 69px, transparent 69px) 0 64px;
    background-color: #708090;
    background-size: 64px 128px;
    -webkit-box-shadow: inset 0 0 70px 10px rgba(0,0,0,.3);
    box-shadow: inset 0 0 70px 10px rgba(0,0,0,.3);
    animation: .8s ease-in 0s 1 slideInFromTop;
}
.background::before {
    opacity: .85;
    width: 100%;
    height: 100%;
    top: 0;
    display: block;
    position: fixed;
    background: linear-gradient(rgba(13,53,106,1), rgba(0,0,0,.2));
    content: '';
}
.black-bg-overlay {
    opacity: 1;
    width: 100%;
    height: 100%;
    top: 0;
    display: block;
    position: fixed;
    background: linear-gradient(rgba(255,255,255,0), rgba(0,0,0,.9));
}