:root {
    --bg-color: #050510;
    --primary: #00f3ff;
    --secondary: #ff00ea;
    --danger: #ff003c;
    --text-main: #ffffff;
    --ui-bg: rgba(5, 5, 16, 0.85);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    user-select: none;
    -webkit-user-select: none;
    font-family: 'Orbitron', sans-serif;
}

body, html {
    width: 100%;
    height: 100%;
    overflow: hidden;
    background-color: var(--bg-color);
    color: var(--text-main);
    touch-action: none; /* Prevent scroll on mobile */
}

#game-container {
    position: relative;
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    background: radial-gradient(circle at center, #11112b 0%, #050510 100%);
}

/* Add a subtle grid background */
#game-container::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background-image: 
        linear-gradient(rgba(0, 243, 255, 0.05) 1px, transparent 1px),
        linear-gradient(90deg, rgba(0, 243, 255, 0.05) 1px, transparent 1px);
    background-size: 40px 40px;
    z-index: 0;
    pointer-events: none;
}

canvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1;
    display: block;
}

#ui-layer {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 5;
    pointer-events: none;
    display: none; /* Hidden until game starts */
}

#top-bar {
    position: absolute;
    top: 20px;
    left: 20px;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.score-container {
    font-size: 24px;
    font-weight: 700;
    color: var(--primary);
    text-shadow: 0 0 10px var(--primary);
}

.combo-container {
    font-size: 32px;
    font-weight: 900;
    color: var(--secondary);
    text-shadow: 0 0 15px var(--secondary);
    transition: transform 0.1s ease-out, opacity 0.3s;
}

.combo-pulse {
    transform: scale(1.3);
}

#health-bar-container {
    position: absolute;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    width: 300px;
    height: 15px;
    background: rgba(255, 255, 255, 0.1);
    border: 2px solid var(--primary);
    border-radius: 10px;
    box-shadow: 0 0 10px rgba(0, 243, 255, 0.5);
    overflow: hidden;
}

#health-bar {
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, var(--primary), #00ff88);
    transition: width 0.2s ease-out, background 0.2s;
}

#health-bar.low {
    background: linear-gradient(90deg, var(--danger), #ffaa00);
    box-shadow: 0 0 15px var(--danger);
}

.icon-btn {
    position: absolute;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: rgba(0, 243, 255, 0.1);
    border: 2px solid var(--primary);
    color: var(--text-main);
    font-size: 20px;
    display: flex;
    justify-content: center;
    align-items: center;
    pointer-events: auto;
    cursor: pointer;
    backdrop-filter: blur(5px);
    transition: all 0.2s;
}

.icon-btn:hover {
    background: rgba(0, 243, 255, 0.3);
    box-shadow: 0 0 15px var(--primary);
    transform: scale(1.1);
}

#pause-btn {
    top: 20px;
    right: 20px;
}

#sound-toggle {
    top: 20px;
    right: 85px;
}

/* Screens */
.screen {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--ui-bg);
    backdrop-filter: blur(10px);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 10;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
}

.screen.active {
    opacity: 1;
    pointer-events: auto;
}

.game-logo {
    width: 120px;
    height: 120px;
    border-radius: 20px;
    box-shadow: 0 0 30px var(--primary);
    margin-bottom: 20px;
    animation: float 3s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-10px); }
}

h1 {
    font-size: 48px;
    color: var(--text-main);
    text-shadow: 0 0 20px var(--primary), 0 0 40px var(--primary);
    margin-bottom: 10px;
    text-align: center;
    letter-spacing: 2px;
}

h2 {
    font-size: 36px;
    color: var(--secondary);
    text-shadow: 0 0 20px var(--secondary);
    margin-bottom: 30px;
    text-align: center;
}

.subtitle {
    font-size: 18px;
    color: #aaa;
    margin-bottom: 40px;
    letter-spacing: 1px;
}

.btn {
    padding: 15px 40px;
    font-size: 20px;
    font-weight: 700;
    border: none;
    border-radius: 30px;
    cursor: pointer;
    margin: 10px;
    transition: all 0.2s;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.primary-btn {
    background: transparent;
    color: var(--primary);
    border: 2px solid var(--primary);
    box-shadow: 0 0 15px rgba(0, 243, 255, 0.4), inset 0 0 15px rgba(0, 243, 255, 0.4);
}

.primary-btn:hover {
    background: var(--primary);
    color: var(--bg-color);
    box-shadow: 0 0 30px var(--primary);
    transform: scale(1.05);
}

.secondary-btn {
    background: transparent;
    color: var(--secondary);
    border: 2px solid var(--secondary);
    box-shadow: 0 0 15px rgba(255, 0, 234, 0.4), inset 0 0 15px rgba(255, 0, 234, 0.4);
}

.secondary-btn:hover {
    background: var(--secondary);
    color: var(--bg-color);
    box-shadow: 0 0 30px var(--secondary);
    transform: scale(1.05);
}

.instruction-content {
    background: rgba(0, 0, 0, 0.5);
    padding: 30px;
    border-radius: 15px;
    border: 1px solid rgba(255, 255, 255, 0.1);
    margin-bottom: 30px;
    max-width: 600px;
    width: 90%;
}

.instruction-content p {
    margin: 15px 0;
    font-size: 18px;
    line-height: 1.5;
}

.final-score, .best-score {
    font-size: 24px;
    margin: 10px 0;
}

.final-score span {
    color: var(--primary);
    font-weight: bold;
    text-shadow: 0 0 10px var(--primary);
}

.best-score span {
    color: #ffd700;
    font-weight: bold;
    text-shadow: 0 0 10px #ffd700;
}

@media (max-width: 768px) {
    h1 { font-size: 32px; }
    h2 { font-size: 28px; }
    .btn { padding: 12px 30px; font-size: 16px; }
    #health-bar-container { width: 80%; }
}