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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    overflow: hidden;
}

.game-container {
    position: relative;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    border-radius: 20px;
    overflow: hidden;
}

#gameCanvas {
    display: block;
    background: linear-gradient(to bottom, #87ceeb 0%, #98d8e8 50%, #90ee90 100%);
}

.ui-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
}

.score-display {
    position: absolute;
    top: 30px;
    left: 50%;
    transform: translateX(-50%);
    font-size: 48px;
    font-weight: bold;
    color: white;
    text-shadow: 3px 3px 6px rgba(0, 0, 0, 0.3);
    z-index: 5;
}

.start-screen,
.game-over-screen {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    background: rgba(255, 255, 255, 0.95);
    padding: 40px 60px;
    border-radius: 20px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
    pointer-events: auto;
}

.start-screen.hidden,
.game-over-screen.hidden {
    display: none;
}

.start-screen h1 {
    font-size: 48px;
    color: #667eea;
    margin-bottom: 20px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.1);
}

.start-screen p {
    font-size: 18px;
    color: #666;
    margin-bottom: 30px;
}

.game-over-screen h2 {
    font-size: 42px;
    color: #e74c3c;
    margin-bottom: 25px;
}

.final-score {
    font-size: 32px;
    color: #667eea;
    font-weight: bold;
    margin-bottom: 15px;
}

.high-score,
.high-score-game-over {
    font-size: 20px;
    color: #888;
    margin-bottom: 25px;
}

.high-score span,
.high-score-game-over span {
    color: #f39c12;
    font-weight: bold;
}

.start-btn,
.restart-btn {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    padding: 15px 40px;
    font-size: 20px;
    font-weight: bold;
    border-radius: 50px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
}

.start-btn:hover,
.restart-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.6);
}

.start-btn:active,
.restart-btn:active {
    transform: translateY(0);
}

/* Responsive design */
@media (max-width: 768px) {
    .start-screen,
    .game-over-screen {
        padding: 30px 40px;
    }
    
    .start-screen h1 {
        font-size: 36px;
    }
    
    .score-display {
        font-size: 36px;
    }
}