:root {
    --background-color: #282828;
    --font-family: Arial, sans-serif;
    --text-color: white;
    --border-color: #fff;
    --highlight-color: yellow;
    --inventory-slot-bg: #444;
}

body, html {
    margin: 0;
    padding: 0;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: var(--background-color);
    font-family: var(--font-family);
    color: var(--text-color);
}

canvas {
    display: block;
    background-color: #000;
    border: 2px solid var(--border-color);
}

#hud {
    position: absolute;
    top: 10px;
    left: 10px;
    display: flex;
    gap: 20px;
    font-size: 18px;
}

#inventory {
    position: absolute;
    bottom: 10px;
    left: 10px;
    display: flex;
    gap: 10px;
}

.inventory-slot {
    width: 50px;
    height: 50px;
    border: 2px solid var(--border-color);
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 14px;
    background-color: var(--inventory-slot-bg);
    position: relative;
}

.inventory-slot.selected {
    border-color: var(--highlight-color);
}

.inventory-slot .cooldown {
    position: absolute;
    top: -20px;
    left: 50%;
    transform: translateX(-50%);
    color: var(--text-color);
    font-size: 14px;
}

.overlay {
    display: none;
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    color: var(--text-color);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

button {
    padding: 10px 20px;
    font-size: 1.2em;
    margin-top: 20px;
    cursor: pointer;
}