:root {
    --bg-color: #0d0d12;
    --neon-pink: #ff00ff;
    --neon-blue: #00ffff;
    --neon-purple: #b026ff;
    --glass-bg: rgba(20, 20, 30, 0.6);
    --glass-border: rgba(255, 255, 255, 0.1);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Inter', 'Segoe UI', system-ui, sans-serif;
}

body {
    background-color: var(--bg-color);
    color: #fff;
    overflow: hidden;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
}

#gameCanvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: 1;
}

#ui-layer {
    position: absolute;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: 10;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    pointer-events: none;
}

#ui-layer > * {
    pointer-events: auto;
}

.glow-text {
    font-size: 4rem;
    color: #fff;
    text-shadow: 0 0 10px var(--neon-pink), 0 0 20px var(--neon-pink), 0 0 40px var(--neon-purple);
    margin-bottom: 2rem;
    text-transform: uppercase;
    letter-spacing: 4px;
    animation: pulse 2s infinite alternate;
}

.glass-panel {
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    padding: 2.5rem;
    width: 90%;
    max-width: 450px;
    text-align: center;
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.5);
    transition: transform 0.3s ease, opacity 0.3s ease;
}

.hidden {
    display: none !important;
}

.track-list {
    display: flex;
    flex-direction: column;
    gap: 1.2rem;
    margin: 2rem 0;
}

button {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--neon-blue);
    color: #fff;
    padding: 1rem 1.5rem;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1.1rem;
    font-weight: bold;
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 1px;
}

button:hover:not(:disabled) {
    background: rgba(0, 255, 255, 0.15);
    box-shadow: 0 0 15px var(--neon-blue);
    transform: scale(1.05);
}

button:active:not(:disabled) {
    transform: scale(0.95);
}

button:disabled {
    opacity: 0.4;
    cursor: not-allowed;
    border-color: #444;
}

.glow-btn {
    border-color: var(--neon-pink);
    background: rgba(255, 0, 255, 0.1);
}

.glow-btn:hover {
    background: rgba(255, 0, 255, 0.25);
    box-shadow: 0 0 20px var(--neon-pink);
}

@keyframes pulse {
    0% {
        text-shadow: 0 0 10px var(--neon-pink), 0 0 20px var(--neon-pink);
    }
    100% {
        text-shadow: 0 0 20px var(--neon-pink), 0 0 40px var(--neon-pink), 0 0 60px var(--neon-purple);
    }
}

.score-board {
    position: absolute;
    top: 30px;
    right: 40px;
    font-size: 2.5rem;
    font-weight: bold;
    text-shadow: 0 0 15px var(--neon-blue);
    transition: transform 0.1s ease;
}

.instruction {
    position: absolute;
    bottom: 40px;
    left: 50%;
    transform: translateX(-50%);
    font-size: 1.2rem;
    color: rgba(255,255,255,0.7);
    letter-spacing: 2px;
    text-shadow: 0 0 5px rgba(255,255,255,0.5);
}

/* Shake animation for canvas */
@keyframes shake {
    0% { transform: translate(1px, 1px) rotate(0deg); }
    10% { transform: translate(-1px, -2px) rotate(-1deg); }
    20% { transform: translate(-3px, 0px) rotate(1deg); }
    30% { transform: translate(3px, 2px) rotate(0deg); }
    40% { transform: translate(1px, -1px) rotate(1deg); }
    50% { transform: translate(-1px, 2px) rotate(-1deg); }
    60% { transform: translate(-3px, 1px) rotate(0deg); }
    70% { transform: translate(3px, 1px) rotate(-1deg); }
    80% { transform: translate(-1px, -1px) rotate(1deg); }
    90% { transform: translate(1px, 2px) rotate(0deg); }
    100% { transform: translate(1px, -2px) rotate(-1deg); }
}

.shake {
    animation: shake 0.2s;
}

#paypal-button-container {
    margin: 2rem 0;
    z-index: 20;
    position: relative;
    min-height: 150px;
}

#btn-close-modal {
    margin-top: 10px;
    border-color: #888;
}

#btn-close-modal:hover {
    box-shadow: 0 0 15px #888;
    background: rgba(136,136,136,0.2);
}

.premium-badge {
    color: var(--neon-blue);
    font-weight: bold;
    letter-spacing: 2px;
    margin-top: 20px;
    text-shadow: 0 0 10px var(--neon-blue);
    animation: pulse 2s infinite alternate;
}