:root {
    --bg-color: #050508;
    --neon-blue: #00d2ff;
    --neon-green: #39ff14;
    --neon-red: #ff003c;
}

body, html {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    background-color: var(--bg-color);
    overflow: hidden;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    color: white;
    user-select: none;
}

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

/* Heads Up Display (HUD) */
#hud {
    position: absolute;
    top: 20px;
    left: 20px;
    right: 20px;
    display: flex;
    justify-content: space-between;
    pointer-events: none;
    z-index: 10;
}

.hud-stat {
    font-size: 24px;
    font-weight: bold;
    text-shadow: 0 0 10px rgba(255, 255, 255, 0.5);
}

#health-bar-container {
    width: 200px;
    height: 20px;
    background: rgba(255, 255, 255, 0.1);
    border: 2px solid white;
    border-radius: 10px;
    overflow: hidden;
    margin-top: 5px;
}

#health-bar {
    width: 100%;
    height: 100%;
    background: var(--neon-blue);
    box-shadow: 0 0 10px var(--neon-blue);
    transition: width 0.2s, background-color 0.2s;
}

/* Menus */
.menu-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(5, 5, 8, 0.85);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 20;
    backdrop-filter: blur(5px);
}

h1 {
    font-size: 60px;
    color: var(--neon-blue);
    text-shadow: 0 0 20px var(--neon-blue);
    margin-bottom: 10px;
    text-align: center;
}

p.instructions {
    font-size: 18px;
    color: #aaa;
    max-width: 600px;
    text-align: center;
    line-height: 1.5;
    margin-bottom: 40px;
}

button {
    padding: 15px 40px;
    font-size: 20px;
    font-weight: bold;
    background: transparent;
    color: var(--neon-blue);
    border: 2px solid var(--neon-blue);
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 2px;
}

button:hover {
    background: var(--neon-blue);
    color: #000;
    box-shadow: 0 0 20px var(--neon-blue);
    transform: scale(1.05);
}

.hidden {
    display: none !important;
}