body {
    background:url('https://images.unsplash.com/photo-1543589077-47d81606c1bf?auto=format&fit=crop&w=800&q=60');
    background-size:cover;
    background-position:center;
    backdrop-filter:blur(2px);
}
.main-container {
    margin-top:70px;
}
.card-box {
    background: rgba(255,255,255,0.85);
    padding:25px;
    border-radius:12px;
}
.btn-main {
    width:100%;
    margin-top:12px;
    font-size:16px;
}
h2 { font-weight:700; text-shadow:0 1px 4px rgba(0,0,0,0.3);}