:root {
    --primary: #6366F1;
    --primary-hover: #4F46E5;
    --secondary: #94A3B8;
    --accent: #22D3EE;
    --bg-color: #0F172A;
    --text-main: #FFFFFF;
    --font-main: 'Inter', system-ui, -apple-system, sans-serif;
    --radius: 12px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    user-select: none;
    -webkit-touch-callout: none;
}

body {
    background-color: var(--bg-color);
    color: var(--text-main);
    font-family: var(--font-main);
    overflow: hidden;
    position: fixed;
    width: 100vw;
    height: 100vh;
}

.game-container {
    position: relative;
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
}

#gameCanvas {
    display: block;
    width: 100%;
    height: 100%;
}

/* UI Layer overlay on top of canvas */
#ui-layer {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none; /* Let clicks pass through unless on buttons */
}

/* Top Stats */
.top-bar {
    position: absolute;
    top: 20px;
    left: 20px;
    right: 20px;
    display: flex;
    justify-content: space-between;
    font-size: 18px;
    font-weight: 700;
    pointer-events: none;
    z-index: 10;
}

.score-box, .high-score-box, .combo-box {
    background: rgba(15, 23, 42, 0.6);
    padding: 8px 16px;
    border-radius: var(--radius);
    border: 1px solid rgba(148, 163, 184, 0.2);
    backdrop-filter: blur(4px);
    transition: opacity 0.3s ease, transform 0.2s ease;
}

.score-box {
    color: var(--text-main);
}

.high-score-box {
    color: var(--secondary);
}

.combo-box {
    color: var(--accent);
    text-shadow: 0 0 10px rgba(34, 211, 238, 0.8);
    transform: scale(1);
}

.combo-pulse {
    animation: comboPop 0.3s ease-out;
}

@keyframes comboPop {
    0% { transform: scale(1); }
    50% { transform: scale(1.3); }
    100% { transform: scale(1); }
}

/* Overlays */
.overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(15, 23, 42, 0.85);
    backdrop-filter: blur(8px);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
    z-index: 20;
    pointer-events: auto;
}

.overlay.active {
    opacity: 1;
    visibility: visible;
}

.title {
    font-size: 48px;
    font-weight: 900;
    color: var(--text-main);
    text-shadow: 0 0 20px var(--primary);
    margin-bottom: 10px;
    text-align: center;
    letter-spacing: 2px;
}

.subtitle {
    font-size: 18px;
    color: var(--secondary);
    margin-bottom: 40px;
    text-align: center;
}

.final-score-text {
    font-size: 24px;
    margin-bottom: 30px;
}

#final-score {
    color: var(--accent);
    font-weight: 700;
}

.controls-hint {
    margin-top: 40px;
    color: var(--secondary);
    font-size: 14px;
    text-align: center;
    line-height: 1.6;
}

/* Buttons */
.btn {
    padding: 16px 32px;
    font-size: 18px;
    font-weight: 700;
    border: none;
    border-radius: var(--radius);
    cursor: pointer;
    font-family: var(--font-main);
    transition: all 0.2s ease;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.primary-btn {
    background: var(--primary);
    color: white;
    box-shadow: 0 4px 15px rgba(99, 102, 241, 0.4);
}

.primary-btn:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(99, 102, 241, 0.6);
}

.primary-btn:active {
    transform: translateY(1px);
}