body {
    font-family: 'Montserrat', sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    background-color: #f7f7f7;
    color: #333;
}

#game-container {
    background-color: white;
    padding: 35px;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    text-align: center;
    max-width: 450px;
    width: 90%;
}

h1 {
    color: #1abc9c; /* Teal */
    margin-bottom: 20px;
}

#score-area {
    font-size: 1.1em;
    font-weight: 600;
    margin-bottom: 15px;
    color: #34495e;
}

/* --- Number Display Area --- */
#number-display-box {
    background-color: #2c3e50; /* Dark background for high contrast */
    color: white;
    font-size: 4em;
    font-weight: bold;
    height: 150px;
    width: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    border-radius: 10px;
    margin-bottom: 30px;
    user-select: none;
    transition: background-color 0.3s;
}

/* --- Controls and Input --- */
#controls {
    display: flex;
    flex-direction: column;
    gap: 15px;
    align-items: center;
}

#start-button {
    padding: 12px 25px;
    font-size: 1.1em;
    font-weight: bold;
    background-color: #1abc9c;
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.2s;
}

#start-button:hover:not(:disabled) {
    background-color: #16a085;
}

#start-button:disabled {
    background-color: #bdc3c7;
    cursor: not-allowed;
}

#input-area {
    display: flex;
    gap: 10px;
    width: 100%;
    justify-content: center;
}

#answer-input {
    padding: 10px;
    font-size: 1em;
    border: 2px solid #ccc;
    border-radius: 5px;
    width: 150px;
    text-align: center;
}

#submit-button {
    padding: 10px 20px;
    font-size: 1em;
    background-color: #3498db; /* Blue */
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.2s;
}

#submit-button:hover:not(:disabled) {
    background-color: #2980b9;
}

#submit-button:disabled {
    background-color: #95a5a6;
    cursor: not-allowed;
}

/* --- Feedback --- */
#feedback-message {
    min-height: 1.5em; 
    margin-top: 20px;
    font-weight: bold;
    font-size: 1.1em;
}