* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
body {
            font-family: 'Segoe UI', Roboto, system-ui, -apple-system, Arial, sans-serif;
            background-image: url('images/bg123.jpg');
            background-size: cover;
            background-position: center;
            background-repeat: no-repeat;
            background-attachment: fixed;
            min-height: 100vh;
            display: flex;
            flex-direction: column;
            animation: fadeIn 1.2s ease-out;
            line-height: 1.6;
        }

        @keyframes fadeIn {
            0% { opacity: 0; backdrop-filter: blur(4px); }
            100% { opacity: 1; backdrop-filter: blur(0); }
        }

        /* glassmorphism header with slide down */
        header {
            background: rgba(0, 115, 230, 0.85);
            backdrop-filter: blur(8px);
            -webkit-backdrop-filter: blur(8px);
            color: white;
            padding: 1.2rem 1rem;
            text-align: center;
            border-bottom: 2px solid rgba(255, 255, 255, 0.2);
            box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.3);
            transform: translateY(0);
            animation: slideDown 0.9s cubic-bezier(0.16, 1, 0.3, 1);
        }

        @keyframes slideDown {
            0% { transform: translateY(-100%); opacity: 0; }
            100% { transform: translateY(0); opacity: 1; }
        }

        .logos {
            display: flex;
            justify-content: center;
            align-items: center;
            gap: clamp(1rem, 4vw, 2.5rem);
            margin-bottom: 0.8rem;
            flex-wrap: wrap;
        }

        .logo {
            width: clamp(50px, 10vw, 75px);
            height: auto;
            filter: drop-shadow(0 4px 6px rgba(0, 0, 0, 0.2));
            transition: transform 0.3s ease, filter 0.3s ease;
            animation: popScale 0.6s ease backwards;
            animation-delay: calc(0.1s * var(--i, 1));
        }

        .logo:hover {
            transform: scale(1.15) rotate(2deg);
            filter: drop-shadow(0 10px 12px rgba(0, 0, 0, 0.3));
        }

        @keyframes popScale {
            0% { transform: scale(0.2); opacity: 0; }
            80% { transform: scale(1.05); }
            100% { transform: scale(1); opacity: 1; }
        }

        /* intro card with soft float */
        .intro {
            background: rgba(255, 255, 255, 0.9);
            backdrop-filter: blur(10px);
            -webkit-backdrop-filter: blur(10px);
            border-radius: 28px;
            padding: clamp(1.5rem, 5vw, 2.5rem);
            margin: 2rem auto;
            max-width: 1100px;
            width: 90%;
            box-shadow: 0 25px 45px -12px rgba(0, 0, 0, 0.35), 0 0 0 1px rgba(255, 255, 255, 0.5) inset;
            transform: translateY(0);
            animation: floatIn 1s ease-out;
            transition: box-shadow 0.3s, transform 0.3s;
        }

        .intro:hover {
            box-shadow: 0 30px 55px -10px rgba(0, 70, 150, 0.4);
            transform: translateY(-4px);
        }

        @keyframes floatIn {
            0% { opacity: 0; transform: translateY(40px) scale(0.98); }
            100% { opacity: 1; transform: translateY(0) scale(1); }
        }

        .intro h2 {
            color: #0b3b5c;
            border-left: 7px solid #0073e6;
            padding-left: 1.2rem;
            margin-bottom: 1.2rem;
            font-weight: 600;
            font-size: clamp(1.5rem, 4vw, 2.2rem);
            letter-spacing: -0.02em;
        }

        .intro p {
            color: #1a2b3c;
            font-size: clamp(1rem, 2.5vw, 1.2rem);
            line-height: 1.7;
            margin-bottom: 0.5rem;
            text-shadow: 0 1px 2px rgba(255,255,255,0.3);
        }

        /* button container with staggered animation */
        .buttons {
            text-align: center;
            margin: 2rem auto 3rem;
            display: flex;
            flex-wrap: wrap;
            justify-content: center;
            gap: 1rem;
            padding: 0 1rem;
            animation: buttonRise 0.8s 0.4s backwards;
        }

        @keyframes buttonRise {
            0% { opacity: 0; transform: translateY(30px); }
            100% { opacity: 1; transform: translateY(0); }
        }

        .btn {
            padding: 0.9rem 2.5rem;
            margin: 0;
            background: linear-gradient(145deg, #0073e6, #005bb5);
            color: white;
            text-decoration: none;
            border-radius: 60px;
            font-weight: 600;
            font-size: 1.2rem;
            letter-spacing: 0.03em;
            box-shadow: 0 12px 20px -10px rgba(0, 60, 130, 0.4), 0 2px 5px rgba(0,0,0,0.1);
            transition: all 0.25s ease;
            border: 1px solid rgba(255, 255, 255, 0.3);
            backdrop-filter: blur(4px);
            flex: 0 1 auto;
            min-width: 160px;
            transform: scale(1);
        }

        .btn:hover {
            background: linear-gradient(145deg, #005bb5, #003f88);
            box-shadow: 0 20px 30px -8px #002856, 0 4px 12px rgba(0, 50, 100, 0.5);
            transform: scale(1.05) translateY(-3px);
            border-color: rgba(255, 255, 255, 0.6);
        }

        .btn:active {
            transform: scale(0.98) translateY(0);
            box-shadow: 0 5px 12px -5px #001d3d;
        }

        /* separate delay for each button */
        .btn:nth-child(1) { animation: btnPop 0.5s 0.5s backwards; }
        .btn:nth-child(2) { animation: btnPop 0.5s 0.65s backwards; }
        .btn:nth-child(3) { animation: btnPop 0.5s 0.8s backwards; }

        @keyframes btnPop {
            0% { opacity: 0; transform: scale(0.5); }
            80% { transform: scale(1.1); }
            100% { opacity: 1; transform: scale(1); }
        }

        /* responsive fine-tuning */
        @media (max-width: 640px) {
            header h1 {
                font-size: 1.5rem;
            }
            .btn {
                padding: 0.7rem 1.8rem;
                font-size: 1rem;
                min-width: 130px;
            }
            .logos {
                gap: 0.8rem;
            }
        }

        @media (max-width: 420px) {
            .btn {
                flex: 1 1 100%;
                max-width: 260px;
            }
            .intro {
                padding: 1.3rem;
            }
        }

        /* extra smooth background overlay */
        body::before {
            content: '';
            position: fixed;
            top: 0; left: 0; right: 0; bottom: 0;
            background: rgba(0, 30, 50, 0.1);
            backdrop-filter: blur(2px);
            z-index: -1;
        }

        /* remove default outline, add accessible focus */
        .btn:focus-visible {
            outline: 3px solid white;
            outline-offset: 3px;
        }