body { 
    margin: 0; 
    overflow: hidden; 
    background-color: #000; 
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; 
    user-select: none; 
}

/* UI Layer */
#ui-layer {
    position: absolute;
    top: 0; 
    left: 0; 
    width: 100%; 
    height: 100%;
    pointer-events: none;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    padding: 20px;
    box-sizing: border-box;
}

/* HUD Elements */
.hud-top { 
    display: flex; 
    justify-content: space-between; 
    align-items: flex-start; 
}

.hud-bottom { 
    display: flex; 
    justify-content: space-between; 
    align-items: flex-end; 
}

#score-board {
    color: #0ff; 
    text-shadow: 0 0 10px #0ff; 
    font-size: 24px; 
    font-weight: bold;
}

#hp-bar-container {
    width: 300px; 
    height: 20px; 
    background: rgba(0,0,0,0.5); 
    border: 2px solid #fff; 
    transform: skewX(-20deg);
}

#hp-bar {
    width: 100%; 
    height: 100%; 
    background: #0f0; 
    transition: width 0.2s, background 0.2s;
}

#crosshair {
    position: absolute; 
    top: 50%; 
    left: 50%; 
    width: 20px; 
    height: 20px;
    transform: translate(-50%, -50%); 
    pointer-events: none;
}

#crosshair::before, #crosshair::after {
    content: ''; 
    position: absolute; 
    background: rgba(255, 255, 255, 0.8);
}

#crosshair::before { 
    top: 9px; 
    left: 0; 
    width: 20px; 
    height: 2px; 
}

#crosshair::after { 
    top: 0; 
    left: 9px; 
    width: 2px; 
    height: 20px; 
}

/* Weapon Selector */
#weapon-selector {
    display: flex; 
    gap: 10px;
}

.weapon-slot {
    padding: 10px 20px; 
    background: rgba(0,0,0,0.5); 
    color: #555; 
    border: 1px solid #333;
    font-weight: bold; 
    transform: skewX(-10deg); 
    transition: 0.2s;
}

.weapon-slot.active {
    background: rgba(0, 255, 255, 0.2); 
    color: #0ff; 
    border-color: #0ff; 
    box-shadow: 0 0 10px #0ff;
}

.weapon-key { 
    font-size: 12px; 
    opacity: 0.7; 
    margin-right: 5px; 
}

/* Game Screens */
#overlay {
    position: absolute; 
    top: 0; 
    left: 0; 
    width: 100%; 
    height: 100%;
    background: rgba(10, 10, 20, 0.85);
    display: flex; 
    flex-direction: column; 
    align-items: center; 
    justify-content: center;
    color: white; 
    pointer-events: auto; 
    z-index: 10; 
    backdrop-filter: blur(5px);
}

h1 { 
    font-size: 64px; 
    margin: 0 0 20px 0; 
    color: #0ff; 
    text-transform: uppercase; 
    letter-spacing: 5px; 
    text-shadow: 0 0 20px #0ff; 
    text-align: center; 
}

.btn {
    padding: 15px 40px; 
    font-size: 24px; 
    color: #000; 
    background: #0ff; 
    border: none;
    cursor: pointer; 
    transform: skewX(-10deg); 
    font-weight: bold; 
    transition: 0.2s;
    margin-top: 20px;
}

.btn:hover { 
    background: #fff; 
    box-shadow: 0 0 20px #fff; 
}

/* Settings Box */
.settings-box {
    margin-top: 25px;
    background: rgba(255, 255, 255, 0.1);
    padding: 15px 25px;
    border-radius: 8px;
    border: 1px solid #444;
    text-align: center;
    width: 320px;
}

.settings-label {
    display: block;
    margin-bottom: 5px;
    color: #0ff;
    font-size: 18px;
    text-align: left;
}

.slider-container {
    margin-bottom: 15px;
}

input[type=range] {
    width: 100%;
    cursor: pointer;
    accent-color: #0ff;
}

.controls-info {
    margin-top: 30px; 
    text-align: center; 
    color: #aaa; 
    line-height: 1.6; 
    background: rgba(255,255,255,0.05); 
    padding: 20px; 
    border-radius: 10px;
}

.key { 
    display: inline-block; 
    padding: 2px 6px; 
    border: 1px solid #666; 
    border-radius: 4px; 
    background: #222; 
    font-family: monospace; 
    color: #fff; 
}

#damage-overlay {
    position: absolute; 
    top: 0; 
    left: 0; 
    width: 100%; 
    height: 100%;
    background: radial-gradient(circle, transparent 50%, rgba(255,0,0,0.6) 100%);
    opacity: 0; 
    pointer-events: none; 
    transition: opacity 0.1s;
}

/* Hitmarker */
#hitmarker {
    position: absolute; 
    top: 50%; 
    left: 50%; 
    width: 30px; 
    height: 30px;
    transform: translate(-50%, -50%) rotate(45deg);
    border: 2px solid transparent; 
    opacity: 0; 
    transition: opacity 0.1s;
}

#hitmarker.hit { 
    border-color: #fff; 
    opacity: 1; 
}

#hitmarker.kill { 
    border-color: #f00; 
    opacity: 1; 
}