:root {
    --void: #030303;
    --void-glass: rgba(0, 0, 0, 0.9);
    --crimson: #990000;
    --crimson-glow: rgba(153, 0, 0, 0.6);
    --bone: #d9d9d9;
    --bone-dim: #777777;
    --gold: #ccaa00;
    --gold-glow: rgba(204, 170, 0, 0.5);
    --stamina-full: rgba(0, 180, 0, 1);
    --stamina-empty: rgba(153, 0, 0, 1);
}

* {
    box-sizing: border-box;
    user-select: none;
}

body, html {
    margin: 0;
    padding: 0;
    overflow: hidden;
    width: 100%;
    height: 100%;
    background-color: var(--void);
    font-family: 'VT323', monospace;
    color: var(--bone);
    text-shadow: 1px 1px 0 #000;
}

canvas {
    display: block;
    width: 100%;
    height: 100%;
    image-rendering: pixelated;
}

/* Scanlines CRT */
.noise-overlay {
    position: fixed;
    inset: 0;
    z-index: 9999;
    pointer-events: none;
    background: 
        linear-gradient(rgba(18, 16, 16, 0) 50%, rgba(0, 0, 0, 0.25) 50%), 
        linear-gradient(90deg, rgba(255, 0, 0, 0.06), rgba(0, 255, 0, 0.02), rgba(0, 0, 255, 0.06));
    background-size: 100% 4px, 3px 100%;
    mix-blend-mode: overlay;
}

/* Mirino */
#crosshair {
    position: absolute;
    top: 50%;
    left: 50%;
    width: 4px;
    height: 4px;
    background-color: rgba(255, 255, 255, 0.8);
    transform: translate(-50%, -50%);
    pointer-events: none;
    z-index: 10;
    box-shadow: 1px 1px 0 #000;
}
#crosshair.active {
    background-color: var(--crimson);
    width: 12px;
    height: 12px;
    border: 2px solid var(--void);
}

/* HUD Torcia */
#torch-battery-hud {
    position: absolute;
    bottom: 62px;
    left: 40px;
    width: 250px;
    font-size: 1.1rem;
    color: var(--bone);
    text-shadow: 1px 1px 0 #000;
    z-index: 10;
    pointer-events: none;
    transition: color 0.2s;
}
#torch-battery-hud.low {
    color: var(--crimson);
}

/* HUD Stamina */
#stamina-container {
    position: absolute;
    bottom: 40px;
    left: 40px;
    width: 250px;
    height: 16px;
    background: #111;
    border: 2px solid #333;
    z-index: 10;
    overflow: hidden;
    box-shadow: 2px 2px 0 #000;
}
#stamina-bar {
    width: 100%;
    height: 100%;
    background: var(--stamina-full);
    transition: width 0.1s steps(10), background-color 0.1s steps(2);
}

/* HUD Inventario */
#key-hud {
    display: none;
    position: absolute;
    bottom: 40px;
    right: 40px;
    width: 64px;
    height: 64px;
    background: #111;
    border: 2px solid var(--gold);
    z-index: 15;
    align-items: center;
    justify-content: center;
    box-shadow: 2px 2px 0 #000;
    animation: slideInUp 0.1s steps(5) forwards;
}
#key-hud img {
    width: 48px;
    height: 48px;
    image-rendering: pixelated;
}

/* Testo Interazione */
#interaction-prompt {
    position: absolute;
    top: calc(50% + 40px);
    left: 50%;
    transform: translateX(-50%);
    color: var(--bone);
    font-size: 1.8rem;
    text-align: center;
    pointer-events: none;
    z-index: 5;
    background: rgba(0,0,0,0.8);
    border: 2px solid #333;
    padding: 8px 16px;
    box-shadow: 4px 4px 0 #000;
    opacity: 0;
    transition: opacity 0.1s;
}
#interaction-prompt.show {
    opacity: 1;
}

/* Messaggi HUD */
#hud-messages {
    position: absolute;
    bottom: 80px;
    left: 50%;
    transform: translateX(-50%);
    color: var(--bone);
    font-size: 1.8rem;
    text-align: center;
    pointer-events: none;
    z-index: 5;
    background: rgba(0,0,0,0.8);
    border: 2px solid #333;
    padding: 8px 16px;
    box-shadow: 4px 4px 0 #000;
    opacity: 0;
}
#hud-messages.show {
    opacity: 1;
}

/* Schermate Overlay */
.overlay-screen {
    position: fixed;
    inset: 0;
    background: rgba(5, 5, 5, 0.95);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    z-index: 30;
    overflow-y: auto;
    padding: 20px;
    box-sizing: border-box;
    opacity: 1;
    transition: opacity 0.6s ease-in;
}

#fade-overlay {
    position: fixed;
    inset: 0;
    background-color: #000;
    z-index: 100;
    pointer-events: none;
    opacity: 0;
    transition: opacity 0.5s steps(10);
}

/* Sangue schermo */
#blood-splatter-overlay {
    position: fixed;
    inset: 0;
    width: 100vw;
    height: 100vh;
    z-index: 9990;
    pointer-events: none;
    opacity: 0;
}

/* Luce vittoria */
#light-burst-overlay {
    position: fixed;
    inset: 0;
    z-index: 9990;
    pointer-events: none;
    opacity: 0;
    background: radial-gradient(circle at 50% 50%,
        rgba(255,250,220,0.95) 0%,
        rgba(255,230,150,0.6) 25%,
        rgba(255,210,100,0.15) 50%,
        transparent 75%);
}

/* Titolo Menu */
.title-container {
    margin-bottom: 40px;
}
.glitch-text {
    font-size: 6rem;
    color: var(--bone);
    margin: 0;
    text-shadow: 4px 4px 0 var(--crimson);
    letter-spacing: 2px;
    text-transform: uppercase;
}
.subtitle {
    font-size: 2rem;
    letter-spacing: 8px;
    color: var(--bone-dim);
    text-transform: uppercase;
    margin-top: 10px;
}

/* Bottoni Menu */
.menu-buttons {
    display: flex;
    flex-direction: column;
    gap: 10px;
    width: 320px;
}
.diff-btn {
    background: #111;
    color: var(--bone);
    border: 2px solid #444;
    padding: 12px 0;
    font-size: 2rem;
    font-family: inherit;
    cursor: pointer;
    text-transform: uppercase;
    box-shadow: 4px 4px 0 #000;
}
.diff-btn:hover {
    color: #fff;
    border-color: var(--crimson);
    background: #200000;
    box-shadow: 4px 4px 0 var(--crimson);
    transform: translate(-2px, -2px);
}
.diff-btn:active {
    transform: translate(2px, 2px);
    box-shadow: 0 0 0 #000;
}

/* Schermata Caricamento */
.pulse-text {
    color: var(--crimson);
    font-size: 3rem;
    letter-spacing: 4px;
    margin-bottom: 30px;
}
.loading-bar-container {
    width: 300px;
    height: 16px;
    background: #111;
    border: 2px solid #444;
    position: relative;
}
#loading-bar-fill {
    position: absolute;
    top: 0; left: 0; height: 100%;
    width: 0%;
    background: var(--crimson);
    transition: width 0.3s ease-out;
}
#loading-text {
    margin-top: 20px;
    color: var(--bone-dim);
    font-size: 1.5rem;
    text-transform: uppercase;
}

/* Schermata Istruzioni */
#instructions {
    display: none;
    z-index: 20;
    background: rgba(0,0,0,0.95);
}
#instructions .title-container {
    margin-bottom: 10px;
}
#instructions .glitch-text {
    font-size: 3rem;
}
#instructions .subtitle {
    font-size: 1.2rem;
    margin-bottom: 5px;
}
#instructions .click-prompt {
    font-size: 1.2rem;
    margin: 5px 0 15px;
}
.click-prompt {
    font-size: 2rem;
    color: var(--bone);
    margin: 10px 0 20px;
    animation: blink 2s steps(2, start) infinite;
}
.controls-list {
    background: #111;
    padding: 10px 20px;
    border: 2px solid #333;
    text-align: left;
    list-style: none;
    box-shadow: 4px 4px 0 #000;
}
.controls-list li {
    margin: 8px 0;
    color: var(--bone);
    font-size: 1.1rem;
}
.kbd {
    background: #222;
    border: 2px solid #555;
    padding: 2px 8px;
    color: #fff;
    margin-right: 15px;
    box-shadow: 2px 2px 0 #000;
    text-transform: uppercase;
}

/* Animazioni */
@keyframes slideInUp {
    from { transform: translateY(20px); }
    to { transform: translateY(0); }
}