:root {
    --bg: #05070a;
    --panel: #11141d;
    --accent: #ff4500;
    --text: #ffffff;
    --subtext: #8b949e;
    --radius: 12px;
    --neon-shadow: 0 0 15px rgba(255, 69, 0, 0.4);
}

* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; outline: none; }

body {
    background-color: var(--bg);
    color: var(--text);
    font-family: 'Inter', sans-serif;
    margin: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    height: 100vh;
    overflow: hidden;
}

/* --- Sound Toggle --- */
#mute-btn {
    position: fixed; top: 15px; right: 15px; z-index: 100;
    cursor: pointer; width: 38px; height: 38px;
    display: flex; align-items: center; justify-content: center;
    background: rgba(255, 255, 255, 0.05); border-radius: 50%;
    border: 1px solid rgba(255, 255, 255, 0.1); font-size: 1.1rem;
    transition: 0.2s;
}
#mute-btn:hover { background: rgba(255, 69, 0, 0.2); border-color: var(--accent); }

/* --- Screens --- */
.screen {
    position: absolute; inset: 0; display: none;
    flex-direction: column; align-items: center; justify-content: center;
    padding: 20px; background: radial-gradient(circle at center, #161b22 0%, #05070a 100%);
    z-index: 10;
}
.screen.active { display: flex; animation: fadeIn 0.4s ease; }

@keyframes fadeIn { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }

/* --- Branding --- */
.brand-container { text-align: center; margin-bottom: 40px; }
.logo-main {
    font-size: 3.5rem; font-weight: 900; color: var(--accent);
    text-transform: uppercase; letter-spacing: -2px; margin: 0;
    animation: neonPulse 2s infinite alternate;
}
.logo-sub { font-size: 1.5rem; letter-spacing: 8px; color: #fff; margin-top: -10px; text-align: center; }

@keyframes neonPulse {
    from { text-shadow: 0 0 10px var(--accent); }
    to { text-shadow: 0 0 20px var(--accent), 0 0 30px #fff; }
}

/* --- Components --- */
.card {
    background: var(--panel); border: 1px solid rgba(255,255,255,0.1);
    border-radius: var(--radius); padding: 24px; width: 100%; max-width: 360px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.5); text-align: center;
}

.btn {
    background: var(--accent); color: white; border: none;
    padding: 16px; border-radius: 8px; width: 100%;
    font-weight: 700; font-size: 1rem; cursor: pointer;
    margin: 8px 0; text-transform: uppercase; transition: 0.2s;
}
.btn:active { transform: scale(0.98); }
.btn-ghost { background: transparent; border: 2px solid var(--accent); color: var(--accent); }

/* --- Game Grid --- */
#grid-container {
    background: var(--panel); border-radius: var(--radius);
    padding: 12px; display: grid; gap: 10px;
    border: 2px solid #30363d; box-shadow: var(--neon-shadow);
    aspect-ratio: 1 / 1; width: 100%; max-width: 500px;
}
.tile {
    background: rgba(255, 255, 255, 0.03); border-radius: 6px;
    display: flex; align-items: center; justify-content: center;
    font-weight: 800; color: #fff;
}
.tile-pop { animation: pop 0.2s ease-out; }
@keyframes pop { 0% { transform: scale(0.5); opacity: 0; } 100% { transform: scale(1); opacity: 1; } }

/* --- HUD --- */
.game-hud { display: flex; justify-content: space-between; width: 100%; max-width: 500px; margin-bottom: 20px; }
.stat-container { display: flex; gap: 10px; }
.stat-box { background: var(--panel); padding: 8px 15px; border-radius: 8px; border-bottom: 2px solid var(--accent); text-align: center; min-width: 80px; }
.stat-label { font-size: 0.6rem; color: var(--subtext); text-transform: uppercase; }
.stat-val { font-weight: bold; }
.home-btn { width: 45px; height: 45px; padding: 0; margin: 0; }

/* --- Overlays --- */
.full-overlay {
    position: absolute; inset: 0; background: rgba(5, 7, 10, 0.95);
    z-index: 150; display: none; flex-direction: column;
    align-items: center; justify-content: center; padding: 30px; text-align: center;
}
.defeat-text { color: var(--accent); font-size: 2.5rem; margin-bottom: 10px; }
.final-score-text { color: var(--subtext); margin-bottom: 20px; }

/* --- Tutorial --- */
.step-dots { display: flex; gap: 8px; margin-bottom: 20px; }
.dot { width: 10px; height: 10px; background: #333; border-radius: 50%; }
.dot.active { background: var(--accent); box-shadow: 0 0 10px var(--accent); }
#tut-title { color: var(--accent); text-transform: uppercase; margin: 0; }
#tut-text { line-height: 1.6; color: var(--subtext); margin-bottom: 30px; }
.tut-action-btn { max-width: 200px; }

/* --- Leaderboard --- */
.screen-title { text-transform: uppercase; letter-spacing: 2px; }
.screen-title.accent { color: var(--accent); }
.lb-container { width: 100%; max-width: 400px; height: 60vh; overflow-y: auto; padding-right: 5px; }
.lb-row { display: flex; justify-content: space-between; align-items: center; padding: 12px 16px; margin-bottom: 8px; background: #1c2128; border-radius: 8px; font-size: 0.9rem; }
.lb-row.me { border: 1px solid var(--accent); background: rgba(255, 69, 0, 0.1); }
.lb-rank { color: var(--accent); font-weight: bold; margin-right: 10px; }
.home-return-btn { max-width: 200px; margin-top: 15px; }