* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: Arial, sans-serif;
}

body {
    background-color: #f5f5f5;
    padding: 20px;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    background-color: white;
    border-radius: 10px;
    padding: 20px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

h1 {
    text-align: center;
    color: #2c3e50;
    margin-bottom: 20px;
}

h2, h3 {
    color: #34495e;
    margin-bottom: 15px;
}

.selection-panel, .operation-panel {
    margin-bottom: 20px;
    padding: 15px;
    border-radius: 8px;
    background-color: #f9f9f9;
}

.operation-buttons {
    display: flex;
    justify-content: space-around;
    flex-wrap: wrap;
    gap: 10px;
}

button {
    padding: 10px 20px;
    background-color: #3498db;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 16px;
    transition: background-color 0.3s;
}

button:hover {
    background-color: #2980b9;
}

.hidden {
    display: none;
}

#operation-display {
    font-size: 28px;
    margin: 20px 0;
    text-align: center;
    background-color: #ecf0f1;
    padding: 15px;
    border-radius: 5px;
}

.answer-section {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
    margin-bottom: 20px;
}

input[type="number"] {
    padding: 10px;
    font-size: 18px;
    border: 2px solid #bdc3c7;
    border-radius: 5px;
    width: 200px;
    text-align: center;
}

.division-inputs {
    display: flex;
    gap: 10px;
}

.division-inputs label {
    font-size: 14px;
    color: #555;
    margin-bottom: 5px;
}

.division-input-group {
    display: flex;
    flex-direction: column;
    align-items: center;
}

#result-feedback {
    text-align: center;
    padding: 15px;
    margin-top: 20px;
    border-radius: 5px;
}

.correct {
    background-color: #d4edda;
    color: #155724;
}

.incorrect {
    background-color: #f8d7da;
    color: #721c24;
}

#feedback-message {
    font-size: 18px;
    margin-bottom: 10px;
}

#correct-answer {
    font-weight: bold;
    margin-bottom: 15px;
}

#new-exercise {
    background-color: #27ae60;
}

#new-exercise:hover {
    background-color: #219653;
}

#examen {
    background-color: #e74c3c;
    display: block;
    margin: 20px auto 0;
    width: fit-content;
}

#examen:hover {
    background-color: #c0392b;
}