body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    margin: 0;
    padding: 10px;
    background-color: #f0f0f0;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

.container {
    max-width: 320px;
    width: 100%;
    background-color: white;
    padding: 0.8rem;
    border-radius: 15px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

h1 {
    text-align: center;
    color: #2c3e50;
    font-size: 1.5rem;
    margin: 0.3rem 0 0.5rem 0;
    font-weight: 600;
}

.instructions {
    background-color: #f8f9fa;
    padding: 0.5rem;
    border-radius: 10px;
    margin-bottom: 0.8rem;
    border: 1px solid #e9ecef;
}

.instructions p {
    text-align: center;
    font-size: 0.9rem;
    color: #2c3e50;
    margin: 0;
}

.instructions ul {
    list-style-type: none;
    padding: 0;
    margin: 0;
}

.instructions li {
    text-align: center;
    padding: 0.3rem 0;
    color: #495057;
    font-size: 0.9rem;
}

.game-area {
    text-align: center;
    padding: 0.5rem;
}

.stats {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.stat-row {
    width: 100%;
    text-align: center;
    padding: 0.3rem;
    background-color: #f8f9fa;
    border-radius: 8px;
    font-size: 0.9rem;
}

.lives-row {
    font-size: 1.2rem;
}

.difference-label {
    margin-right: 0.5rem;
}

.cents-label {
    margin-left: 0.2rem;
    color: #666;
}

.primary-button {
    background-color: #4CAF50;
    color: white;
    padding: 1.2rem 1.2rem;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1.1rem;
    margin: 0.3rem;
    transition: all 0.3s ease;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.primary-button:hover {
    background-color: #45a049;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.2);
}

.answer-buttons {
    margin-top: 0.8rem;
    display: flex;
    justify-content: center;
    gap: 0.8rem;
}

.answer-button {
    background-color: #3498db;
    color: white;
    padding: 1.2rem 0.8rem;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1.1rem;
    transition: all 0.3s ease;
    flex: 1;
    min-width: 100px;
    max-width: 120px;
}

.answer-button:disabled {
    background-color: #bdc3c7;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.answer-button:hover:not(:disabled) {
    background-color: #2980b9;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.2);
}

.game-over {
    text-align: center;
    margin-top: 1rem;
    padding: 1rem;
    background-color: #f8f9fa;
    border-radius: 10px;
}

.game-over h2 {
    color: #2c3e50;
    font-size: 1.5rem;
    margin: 0.5rem 0;
}

.hearts {
    letter-spacing: 4px;
    font-size: 1.4em;
}

.hidden {
    display: none;
}

@media (max-width: 600px) {
    body {
        padding: 5px;
    }

    .container {
        padding: 0.6rem;
    }

    h1 {
        font-size: 1.5rem;
        margin-bottom: 0.5rem;
    }

    .stats {
        gap: 0.3rem;
    }

    .stat-row {
        padding: 0.2rem;
    }

    .hearts {
        font-size: 1.2em;
    }

    .answer-buttons {
        flex-direction: row;
    }

    .answer-button {
        padding: 0.6rem 1rem;
        font-size: 0.9rem;
    }

    .popup-content {
        padding: 0.8rem 1.5rem;
        font-size: 1.2rem;
    }
}

@media (max-width: 360px) {
    .container {
        max-width: 100%;
        padding: 0.6rem;
    }

    .answer-button {
        min-width: 90px;
        padding: 1.2rem 0.5rem;
    }
}

.popup {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

.popup-content {
    background-color: white;
    padding: 1rem 2rem;
    border-radius: 10px;
    font-size: 1.5rem;
    font-weight: bold;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
    animation: popupFadeIn 0.3s ease;
}

@keyframes popupFadeIn {
    from { 
        opacity: 0;
        transform: scale(0.8);
    }
    to { 
        opacity: 1;
        transform: scale(1);
    }
}

.popup.hidden {
    display: none;
}

.correct-message {
    color: #2ecc71;
}

.incorrect-message {
    color: #e74c3c;
}