html, body {
    height: 100%;
}
.login-bg {
    position: fixed;
    inset: 0;
    z-index: -1;
    overflow: hidden;
}
.bg-slide {
    position: absolute;
    inset: 0;
    background-size: cover;
    background-position: center;
    opacity: 0;
    animation: fade 24s infinite;
}
.bg-slide:nth-child(1) { animation-delay: 0s; }
.bg-slide:nth-child(2) { animation-delay: 6s; }
.bg-slide:nth-child(3) { animation-delay: 12s; }
.bg-slide:nth-child(4) { animation-delay: 18s; }
@keyframes fade {
    0% { opacity: 0; }
    8% { opacity: 1; }
    25% { opacity: 1; }
    33% { opacity: 0; }
    100% { opacity: 0; }
}
.login-card {
    backdrop-filter: blur(6px);
    background: rgba(255,255,255,0.85);
    border-radius: 12px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
}
.navbar-brand {
    font-weight: 700;
    letter-spacing: .5px;
}
.table thead th {
    white-space: nowrap;
}