@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@300;400;500;600;700&display=swap');
        
        body {
            font-family: 'Poppins', sans-serif;
            background: linear-gradient(135deg, #1a2a6c, #b21f1f, #fdbb2d);
            min-height: 100vh;
            overflow-x: hidden;
        }
        
        .staff-container {
            position: relative;
            height: 220px;
            background: #f8f0d7;
            border-radius: 12px;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
            overflow: hidden;
        }
        
        .staff-line {
            position: absolute;
            width: 100%;
            height: 2px;
            background: #000;
            left: 0;
        }
        
        .note {
            position: absolute;
            width: 60px;
            height: 100px;
            z-index: 10;
            cursor: pointer;
        }
        
        .note-img {
            width: 100%;
            height: 100%;
            object-fit: contain;
            transition: transform 0.2s;
        }
        
        .note:hover .note-img {
            transform: scale(1.1);
        }
        
        .clef {
            position: absolute;
            font-size: 160px;
            left: 10px;
            top: 54%;
            transform: translateY(-50%);
            z-index: 1;
            line-height: 0.8;
        }
        
        .game-card {
            background: rgba(255, 255, 255, 0.92);
            border-radius: 20px;
            backdrop-filter: blur(10px);
            box-shadow: 0 15px 35px rgba(0, 0, 0, 0.2);
            transition: transform 0.3s ease;
        }
        
        .game-card:hover {
            transform: translateY(-5px);
        }
        
        .btn-note {
            transition: all 0.2s ease;
            box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
        }
        
        .btn-note:hover {
            transform: translateY(-3px);
            box-shadow: 0 6px 8px rgba(0, 0, 0, 0.15);
        }
        
        .btn-note:active {
            transform: translateY(1px);
        }
        
        .pulse {
            animation: pulse 1.5s infinite;
        }
        
        @keyframes pulse {
            0% { transform: scale(1); }
            50% { transform: scale(1.05); }
            100% { transform: scale(1); }
        }
        
        .progress-bar {
            height: 10px;
            border-radius: 5px;
            transition: width 0.5s ease;
        }
        
        .note-animation {
            animation: noteSlide 0.8s ease-out forwards;
        }
        
        @keyframes noteSlide {
            0% { opacity: 0; transform: translateX(-50px); }
            100% { opacity: 1; transform: translateX(0); }
        }
        
        .correct {
            background: #48bb78 !important;
            animation: correctBlink 0.5s;
        }

        /* Checkmark animation */
        .checkmark-circle {
            width: 150px;
            height: 150px;
            position: relative;
            display: inline-block;
        }
        
        .checkmark-circle-bg {
            fill: #4CAF50;
            opacity: 0;
            animation: fadeIn 0.3s ease-out forwards;
        }
        
        .checkmark {
            width: 150px;
            height: 150px;
            border-radius: 50%;
            display: block;
            stroke-width: 5;
            stroke: #4CAF50;
            stroke-miterlimit: 10;
            animation: fill .3s ease-out .3s forwards, scale .2s ease-out .6s both;
        }
        
        .checkmark-check {
            transform-origin: 50% 50%;
            stroke-dasharray: 48;
            stroke-dashoffset: 48;
            animation: stroke .3s cubic-bezier(0.65, 0, 0.45, 1) .8s forwards;
        }
        
        @keyframes fadeIn {
            100% { opacity: 0.2; }
        }
        
        @keyframes stroke {
            100% { stroke-dashoffset: 0; }
        }
        
        @keyframes scale {
            0%, 100% { transform: none; }
            50% { transform: scale3d(1.1, 1.1, 1); }
        }
        
        @keyframes fill {
            100% { box-shadow: inset 0px 0px 0px 30px #4CAF50; }
        }
        
        /* Stars popup */
        .stars-popup {
            background: rgba(0,0,0,0.8);
            border-radius: 20px;
            padding: 2rem;
            text-align: center;
            max-width: 500px;
            width: 90%;
            border: 2px solid rgba(255, 215, 0, 0.5);
            box-shadow: 0 0 30px rgba(255, 215, 0, 0.5);
        }
        
        .stars-container {
            position: relative;
            width: 300px;
            height: 300px;
            margin: 0 auto;
            perspective: 1000px;
        }
        
        .star {
            position: absolute;
            background: url('https://www.freepnglogos.com/uploads/star-png/star-vector-png-transparent-image-pngpix-21.png') no-repeat center center;
            background-size: contain;
            width: 100%;
            height: 100%;
            opacity: 0;
            filter: drop-shadow(0 0 15px gold);
        }
        
        .star-1 { 
            animation: starGlow 0.8s 0.1s forwards, float 3s 0.1s ease-in-out infinite; 
        }
        .star-2 { 
            animation: starGlow 0.8s 0.2s forwards, float 3.5s 0.2s ease-in-out infinite; 
        }
        .star-3 { 
            animation: starGlow 0.8s 0.3s forwards, float 4s 0.3s ease-in-out infinite; 
        }
        .star-4 { 
            animation: starGlow 0.8s 0.4s forwards, float 3.2s 0.4s ease-in-out infinite; 
        }
        .star-5 { 
            animation: starGlow 0.8s 0.5s forwards, float 3.7s 0.5s ease-in-out infinite; 
        }
        
        @keyframes starGlow {
            0% { transform: scale(0); opacity: 0; filter: drop-shadow(0 0 0 gold); }
            50% { transform: scale(1.5); opacity: 1; filter: drop-shadow(0 0 30px gold); }
            100% { transform: scale(1); opacity: 1; filter: drop-shadow(0 0 15px gold); }
        }
        
        @keyframes float {
            0%, 100% { transform: translateY(0) rotate(0deg); }
            50% { transform: translateY(-20px) rotate(10deg); }
        }
        
        @keyframes rotate {
            100% { transform: rotateY(360deg); }
        }
        
        @keyframes animate-popIn {
            0% { transform: scale(0.5); opacity: 0; }
            100% { transform: scale(1); opacity: 1; }
        }
        
        .incorrect {
            background: #e53e3e !important;
            animation: shake 0.5s;
        }
        
        .clicked-once {
            background: #8b5cf6 !important;
            animation: pulse 0.5s;
        }
        
        .clicked-twice {
            background: #7c3aed !important;
            animation: pulse 0.5s;
        }
        
        @keyframes correctBlink {
            0%, 100% { background: #48bb78; }
            50% { background: #68d391; }
        }
        
        @keyframes shake {
            0%, 100% { transform: translateX(0); }
            25% { transform: translateX(-10px); }
            75% { transform: translateX(10px); }
        }
        
        .level-indicator {
            transition: all 0.4s cubic-bezier(0.68, -0.55, 0.265, 1.55);
            position: relative;
            overflow: hidden;
            border: 2px solid rgba(255,255,255,0.1);
            filter: brightness(0.7);
            opacity: 0.8;
        }
        
        .level-indicator::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: linear-gradient(45deg, rgba(255,255,255,0.2), transparent);
            z-index: 1;
            opacity: 0;
            transition: all 0.4s ease;
        }
        
        .level-indicator::after {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: linear-gradient(135deg, rgba(255,255,255,0.3), transparent);
            z-index: 1;
            opacity: 0;
            transition: all 0.4s ease;
        }
        
        .level-indicator.active {
            transform: scale(1.05);
            box-shadow: 0 10px 25px rgba(0,0,0,0.3);
            z-index: 10;
            filter: brightness(1);
            opacity: 1;
            border-color: rgba(255,255,255,0.3);
        }
        
        .level-indicator.active::before,
        .level-indicator.active::after {
            opacity: 1;
        }
        
        .level-indicator.unlocked {
            animation: unlockPulse 1s ease forwards;
            filter: brightness(1);
            opacity: 1;
        }
        
        .level-indicator.active .level-badge {
            transform: scale(1.2);
            box-shadow: 0 4px 15px rgba(0,0,0,0.3);
            background: rgba(255,255,255,0.3) !important;
        }
        
        @keyframes unlockPulse {
            0% { transform: scale(1); box-shadow: 0 0 0 rgba(255,255,255,0); }
            50% { transform: scale(1.1); box-shadow: 0 0 20px rgba(255,255,255,0.8); }
            100% { transform: scale(1); box-shadow: 0 0 0 rgba(255,255,255,0); }
        }
        
        .level-badge {
            transition: all 0.4s cubic-bezier(0.68, -0.55, 0.265, 1.55);
        }
        
        @keyframes levelTransition {
            0% { transform: translateY(0) scale(1); opacity: 1; }
            50% { transform: translateY(-20px) scale(1.2); opacity: 0; }
            100% { transform: translateY(0) scale(1); opacity: 1; }
        }
        
        .music-key {
            width: 40px;
            height: 40px;
            border-radius: 8px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: bold;
            box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
        }
        
        .current-note {
            filter: drop-shadow(0 0 8px gold) brightness(1.2);
            animation: noteGlow 1.5s infinite alternate;
        }

        @keyframes noteGlow {
            0% { filter: drop-shadow(0 0 5px gold) brightness(1.1); }
            100% { filter: drop-shadow(0 0 15px gold) brightness(1.3); }
        }
        
        /* Ledger lines */
        .ledger-line {
            position: absolute;
            width: 60px;
            height: 2px;
            background: #000;
            z-index: 5;
        }
        
        /* High note positions */
        .high-note {
            position: absolute;
            width: 60px;
            height: 100px;
            z-index: 10;
        }