* { margin: 0; padding: 0; box-sizing: border-box; font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; }
        body { background: #000; height: 100vh; display: flex; align-items: center; justify-content: center; overflow: hidden; }
        
        /* --- KONTENER I TŁA (EFEKT KEN BURNS) --- */
        .background-slider {
            position: fixed; top: 0; left: 0; width: 100%; height: 100%; z-index: -2;
            background-color: #000;
        }
        .slide {
            position: absolute; top: 0; left: 0; width: 100%; height: 100%;
            background-size: cover; background-position: center;
            opacity: 0; visibility: hidden;
            transition: opacity 3s ease-in-out, visibility 3s;
            transform: scale(1.05);
            animation: kenburns 30s linear infinite;
        }
        .slide.active { 
            opacity: 0.7; /* Zwiększono krycie zdjęcia (było 0.5) */
            visibility: visible; 
        }

        @keyframes kenburns {
            0% { transform: scale(1.05); }
            100% { transform: scale(1.2); }
        }

        .overlay {
            position: fixed; top: 0; left: 0; width: 100%; height: 100%;
            /* Zmniejszono intensywność gradientu (z 0.75 na 0.5) */
            background: radial-gradient(circle, rgba(0,0,0,0.2) 0%, rgba(0,0,0,0.5) 100%);
            z-index: -1;
        }

        /* --- KARTA LOGOWANIA --- */
        .login-card {
            background: rgba(20, 20, 20, 0.4);
            backdrop-filter: blur(15px);
            -webkit-backdrop-filter: blur(15px);
            padding: 40px;
            border-radius: 20px;
            border: 1px solid rgba(255, 255, 255, 0.2);
            width: 100%;
            max-width: 400px;
            color: white;
            text-align: center;
            box-shadow: 0 20px 50px rgba(0,0,0,0.5);
            z-index: 10;
        }
        h1 { font-size: 24px; font-weight: 300; margin-bottom: 30px; letter-spacing: 2px; text-transform: uppercase; }
        .input-group { margin-bottom: 20px; text-align: left; }
        label { display: block; font-size: 12px; margin-bottom: 5px; color: #aaa; text-transform: uppercase; letter-spacing: 1px; }
        input {
            width: 100%; padding: 12px; background: rgba(255,255,255,0.1); border: none;
            border-bottom: 1px solid rgba(255,255,255,0.5);
            color: white; font-size: 16px; outline: none; transition: 0.3s;
        }
        input:focus { border-bottom-color: #fff; background: rgba(255,255,255,0.2); }
        button {
            width: 100%; padding: 14px; background: white; color: black; border: none;
            border-radius: 30px; font-weight: bold; cursor: pointer; text-transform: uppercase;
            letter-spacing: 1px; margin-top: 10px; transition: transform 0.2s, background 0.3s;
        }
        button:hover { background: #eee; transform: scale(1.02); }
        .error { color: #ff6b6b; font-size: 14px; margin-bottom: 20px; }

        @media (max-width: 768px) {
            .login-card { width: 90%; padding: 30px; }
            .slide { animation: kenburns-mobile 20s linear infinite; }
        }
        @keyframes kenburns-mobile {
            0% { transform: scale(1.0); }
            100% { transform: scale(1.1); }
        }