:root {
    --bg: #020617;
    --pac-yellow: #f8fb02;
    --neon-blue: #0ea5e9;
    --neon-pink: #f43f5e;
    --neon-green: #10b981;
    --text: #f8fafc;
    --glass: rgba(15, 23, 42, 0.4);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    background-color: var(--bg);
    color: var(--text);
    font-family: 'Orbitron', sans-serif;
    overflow: hidden;
    height: 100vh;
}

.arcade-wrapper {
    display: flex;
    flex-direction: column;
    height: 100%;
}

.game-header {
    background: #000;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 2px solid var(--neon-blue);
    box-shadow: 0 0 20px rgba(14, 165, 233, 0.2);
}

.back-link {
    color: var(--neon-pink);
    text-decoration: none;
    font-weight: bold;
    font-size: 0.8rem;
    letter-spacing: 2px;
}

.hud {
    display: flex;
    gap: 3rem;
    font-weight: 900;
    color: var(--neon-blue);
    text-shadow: 0 0 10px var(--neon-blue);
    font-size: 1.2rem;
}

/* stage */
#game-stage {
    flex-grow: 1;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    background: #000;
}

#gameCanvas {
    background: #000;
}

/* Modals & Overlays */
.modal, .overlay {
    position: absolute;
    inset: 0;
    background: rgba(0,0,0,0.4);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
}

.hidden {
    display: none !important;
}

.glass {
    background: var(--glass);
    border: 2px solid var(--neon-blue);
    padding: 3rem;
    border-radius: 25px;
    text-align: center;
    backdrop-filter: blur(8px);
    box-shadow: 0 0 50px rgba(14, 165, 233, 0.3);
    max-width: 500px;
}

.formula {
    font-family: 'JetBrains Mono', monospace;
    font-size: 2.5rem;
    margin: 2rem 0;
    color: #fff;
    text-shadow: 0 0 15px var(--pac-yellow);
}

.answer-row {
    font-size: 2.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    margin-bottom: 2rem;
}

.answer-row input {
    background: #000;
    border: 2px solid var(--neon-pink);
    color: var(--neon-pink);
    width: 80px;
    font-size: 1.5rem;
    padding: 0.5rem;
    text-align: center;
    border-radius: 8px;
    font-family: 'Orbitron', sans-serif;
    vertical-align: super;
}

.btn-neon {
    background: transparent;
    border: 2px solid var(--neon-blue);
    color: var(--neon-blue);
    padding: 1rem 3rem;
    font-family: 'Orbitron', sans-serif;
    font-weight: 800;
    cursor: pointer;
    transition: 0.3s;
}

.btn-neon:hover {
    background: var(--neon-blue);
    color: #000;
    box-shadow: 0 0 30px var(--neon-blue);
}

.neon-text {
    font-size: 4rem;
    color: var(--pac-yellow);
    text-shadow: 0 0 20px var(--pac-yellow);
    margin-bottom: 2rem;
}

.feedback {
    margin-top: 1rem;
    height: 1.2rem;
    font-size: 0.9rem;
}

/* pulse effect */
.icon-pulse {
    font-size: 3rem;
    color: #fce38a;
    animation: pulse 1s infinite alternate;
}

@keyframes pulse {
    from { transform: scale(1); opacity: 0.6; }
    to { transform: scale(1.2); opacity: 1; }
}