
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: 'Georgia', serif;
            height: 100vh;
            background: linear-gradient(135deg, #87CEEB 0%, #FFB6C1 100%);
            display: flex;
            justify-content: center;
            align-items: center;
            overflow: hidden;
            transition: background 0.5s ease;
        }

        body.dark {
            background: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
        }

        .card {
            width: 400px;
            height: 600px;
            background: rgba(255, 255, 255, 0.95);
            border-radius: 20px;
            box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
            display: flex;
            flex-direction: column;
            justify-content: center;
            align-items: center;
            position: relative;
            transition: transform 0.3s ease, background 0.5s ease, box-shadow 0.5s ease;
            padding: 40px;
            text-align: center;
            animation: auto-bounce 4s ease-in-out infinite;
        }

        body.dark .card {
            background: rgba(30, 30, 50, 0.95);
            box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
        }

        .card:hover {
            transform: scale(1.02);
        }

        .birthday-icon {
            margin-bottom: 30px;
            animation: bounce 2s infinite;
        }

        .main-text {
            font-size: 2.5rem;
            font-weight: bold;
            color: #4A90E2;
            margin-bottom: 10px;
            text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.1);
            transition: color 0.5s ease;
        }

        body.dark .main-text {
            color: #87CEEB;
        }

        .char {
            display: inline-block;
            opacity: 0;
            animation: typewriter 0.5s ease-in-out forwards;
        }

        .name {
            font-size: 3rem;
            font-weight: bold;
            background: linear-gradient(45deg, #4A90E2, #FF69B4);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
            margin-bottom: 20px;
            animation: shimmer 3s infinite;
        }

        .message {
            font-size: 1.2rem;
            color: #666;
            line-height: 1.6;
            margin-bottom: 30px;
            transition: color 0.5s ease;
        }

        body.dark .message {
            color: #ccc;
        }

        .theme-toggle {
            position: absolute;
            top: 20px;
            right: 20px;
            background: rgba(255, 255, 255, 0.2);
            border: 2px solid rgba(255, 255, 255, 0.3);
            border-radius: 50px;
            padding: 10px 20px;
            cursor: pointer;
            font-size: 1.2rem;
            transition: all 0.3s ease;
            backdrop-filter: blur(10px);
        }

        .theme-toggle:hover {
            background: rgba(255, 255, 255, 0.3);
            transform: scale(1.05);
        }

        body.dark .theme-toggle {
            background: rgba(0, 0, 0, 0.2);
            border-color: rgba(255, 255, 255, 0.2);
        }

        .celebrate-btn {
            background: linear-gradient(45deg, #4A90E2, #FF69B4);
            border: none;
            border-radius: 50px;
            padding: 15px 30px;
            color: white;
            font-size: 1.1rem;
            font-weight: bold;
            cursor: pointer;
            transition: all 0.3s ease;
            box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
            margin-top: 20px;
        }

        .celebrate-btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 8px 25px rgba(0, 0, 0, 0.3);
        }

        .celebrate-btn:active {
            transform: translateY(0);
        }

        .confetti {
            position: absolute;
            width: 10px;
            height: 10px;
            opacity: 0;
            pointer-events: none;
        }

        .confetti.active {
            animation: confetti-fall 3s ease-out forwards;
        }

        .balloon {
            position: absolute;
            opacity: 0;
            pointer-events: none;
        }

        .balloon.active {
            animation: balloon-rise 4s ease-out forwards;
        }

        @keyframes bounce {
            0%, 20%, 50%, 80%, 100% { transform: translateY(0); }
            40% { transform: translateY(-10px); }
            60% { transform: translateY(-5px); }
        }

        @keyframes auto-bounce {
            0%, 100% { transform: translateY(0) scale(1); }
            50% { transform: translateY(-5px) scale(1.01); }
        }

        @keyframes typewriter {
            0% {
                opacity: 0;
                transform: translateY(10px);
            }
            100% {
                opacity: 1;
                transform: translateY(0);
            }
        }

        @keyframes shimmer {
            0% { background-position: -200% center; }
            100% { background-position: 200% center; }
        }

        @keyframes pulse {
            0%, 100% { opacity: 0.6; }
            50% { opacity: 1; }
        }

        @keyframes confetti-fall {
            0% {
                opacity: 1;
                transform: translateY(-100vh) rotate(0deg);
            }
            100% {
                opacity: 0;
                transform: translateY(100vh) rotate(720deg);
            }
        }

        @keyframes balloon-rise {
            0% {
                opacity: 1;
                transform: translateY(100vh) scale(0.5);
            }
            50% {
                opacity: 1;
                transform: translateY(-20vh) scale(1);
            }
            100% {
                opacity: 0;
                transform: translateY(-100vh) scale(0.8);
            }
        }

        @keyframes card-celebrate {
            0%, 100% { transform: scale(1) rotate(0deg); }
            25% { transform: scale(1.05) rotate(1deg); }
            75% { transform: scale(1.05) rotate(-1deg); }
        }

        .celebrating {
            animation: card-celebrate 0.6s ease-in-out;
        }

        @media (max-width: 480px) {
            .card {
                width: 90%;
                height: 80%;
                padding: 30px 20px;
            }
            
            .main-text {
                font-size: 2rem;
            }
            
            .name {
                font-size: 2.5rem;
            }
            
            .message {
                font-size: 1rem;
            }
        }
    