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

body {
    font-family: Arial, sans-serif;
    background-color: #333;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    color: white;
}

#game-container {
    position: relative;
    width: 800px;
    height: 600px;
    border: 2px solid #666;
    overflow: hidden;
    background-color: #111; /* Darker background for container */
}

#game-canvas {
    position: absolute;
    top: 0;
    left: 0;
    width: calc(100% - 200px); /* Account for upgrade menu */
    height: 100%;
    background-color: #222;
    display: block; /* Ensure canvas is displayed */
}

#ui-overlay {
    position: absolute;
    top: 10px;
    left: 10px;
    font-size: 20px;
    text-shadow: 2px 2px 2px rgba(0, 0, 0, 0.8);
}

#ui-overlay div {
    margin-bottom: 10px;
}

#upgrade-menu {
    position: absolute;
    right: 0;
    top: 0;
    background-color: rgba(0, 0, 0, 0.7);
    padding: 10px;
    width: 200px;
    height: 100%;
    border-left: 1px solid #666;
}

#upgrade-menu h2 {
    text-align: center;
    margin-bottom: 15px;
    border-bottom: 1px solid #666;
    padding-bottom: 5px;
}

.upgrade {
    display: flex;
    flex-direction: column;
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 1px solid #444;
}

.upgrade button {
    margin-top: 5px;
    padding: 5px;
    background-color: #007acc;
    border: none;
    color: white;
    cursor: pointer;
    border-radius: 3px;
}

.upgrade button:hover {
    background-color: #0099ff;
}

.upgrade button:disabled {
    background-color: #555;
    cursor: not-allowed;
}

#stats {
    margin-top: 20px;
    border-top: 1px solid #666;
    padding-top: 10px;
}

#stats h3 {
    text-align: center;
    margin-bottom: 10px;
}

#stats div {
    margin-bottom: 5px;
}