body { 
    margin: 0; 
    overflow: hidden; 
    background-color: #000; 
    font-family: 'Courier New', Courier, monospace; 
}

canvas { 
    display: block; 
    width: 100vw; 
    height: 100vh; 
}

#menu-overlay, #pause-overlay, #game-over-overlay, #shop-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(10, 0, 20, 0.8);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 10;
}

.hidden {
    display: none !important;
}

#menu-overlay h1, #pause-overlay h1, #game-over-overlay h1, #shop-overlay h1 {
    color: #fff;
    text-shadow: 0 0 10px #fff, 0 0 20px #ff00ff, 0 0 30px #ff00ff;
    font-size: 4em;
    margin-bottom: 50px;
}

#game-over-overlay h2 {
    color: #ffd700;
    font-size: 2em;
    margin-top: -30px;
    margin-bottom: 30px;
    text-shadow: 0 0 8px #ffd700;
}

.menu-button {
    background: none;
    border: 2px solid;
    padding: 15px 30px;
    font-size: 1.5em;
    color: #00ffff;
    text-shadow: 0 0 8px #00ffff;
    border-color: #00ffff;
    border-radius: 10px;
    margin: 10px;
    cursor: pointer;
    transition: color 0.3s, text-shadow 0.3s, border-color 0.3s;
    min-width: 200px;
    box-sizing: border-box;
}

.menu-button:hover {
    color: #fff;
    border-color: #fff;
    text-shadow: 0 0 10px #fff, 0 0 20px #ff00ff;
}

#instructions {
    position: absolute;
    top: 10px;
    left: 50%;
    transform: translateX(-50%);
    color: white;
    font-size: 1.2em;
    background-color: rgba(0,0,0,0.5);
    padding: 10px 20px;
    border-radius: 10px;
    pointer-events: none;
    transition: opacity 0.5s;
    opacity: 0;
}

#score-display {
    position: absolute;
    top: 20px;
    left: 20px;
    color: #ffd700;
    font-size: 1.5em;
    text-shadow: 1px 1px 2px #000;
    z-index: 10;
}

#coin-display-shop {
    font-size: 1.8rem;
    margin-bottom: 25px;
    color: #ffd700;
    text-shadow: 0 0 5px #ffd700;
}

#shop-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
    gap: 20px;
    width: 80%;
    max-width: 800px;
    max-height: 60vh;
    overflow-y: auto;
    padding: 20px;
    border: 1px solid rgba(0, 255, 255, 0.3);
    border-radius: 10px;
    background: rgba(0, 0, 0, 0.2);
    margin-bottom: 20px;
}

.shop-item {
    background: rgba(0, 0, 0, 0.4);
    border: 1px solid #00ffff;
    border-radius: 10px;
    padding: 10px;
    text-align: center;
    transition: transform 0.2s;
}

.shop-item:hover {
    transform: scale(1.05);
    box-shadow: 0 0 15px #00ffff;
}

.shop-item img {
    width: 100%;
    height: 120px;
    object-fit: cover;
    border-radius: 5px;
    margin-bottom: 10px;
    border: 1px solid #00ffff;
}

.shop-item .item-name {
    font-size: 1.1rem;
    margin-bottom: 5px;
    color: #fff;
}

.shop-item .item-price {
    font-size: 1rem;
    color: #ffd700;
    margin-bottom: 10px;
}

.buy-button {
    width: 100%;
    padding: 8px;
    font-size: 1rem;
    font-family: 'Courier New', Courier, monospace;
    background-color: #00ffff;
    color: #000;
    font-weight: bold;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s;
}

.buy-button:hover:not(:disabled) {
    background-color: #8affff;
}

.buy-button.equipped {
    background-color: #ff00ff;
    color: #fff;
    cursor: default;
}

.buy-button.purchased {
    background-color: #555;
    color: #ccc;
}

.buy-button:disabled:not(.equipped) {
    background-color: #333;
    color: #666;
    cursor: not-allowed;
}