body {
    font-family: 'Arial', sans-serif;
    background-color: #f4f4f4;
    color: #333;
    margin: 0;
    line-height: 1.6;
    transition: background 0.3s, color 0.3s;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: #3498db;
    color: white;
    padding: 15px 20px;
}

header h2 {
    margin: 0;
    font-size: 20px;
}

#theme-toggle {
    background: #2c3e50;
    color: white;
    border: none;
    padding: 8px 12px;
    border-radius: 6px;
    cursor: pointer;
}

.filters {
    max-width: 800px;
    margin: 15px auto;
    padding: 10px;
}

label {
    font-weight: bold;
    display: block;
    margin-top: 10px;
}

select, input {
    width: 100%;
    padding: 10px;
    border: 1px solid #bbb;
    border-radius: 6px;
    background-color: #ecf0f1;
    font-size: 16px;
}

#quiz-container {
    max-width: 800px;
    margin: 20px auto;
    background: #fff;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 0 15px rgba(0, 0, 0, 0.1);
}

.question-card {
    margin-bottom: 30px;
    border-bottom: 1px solid #ddd;
    padding-bottom: 15px;
}

ul {
    list-style: none;
    padding: 0;
}

.option-btn, .solution-button {
    background-color: #3498db;
    color: white;
    border: none;
    padding: 10px;
    border-radius: 6px;
    width: 100%;
    margin-top: 5px;
    cursor: pointer;
    transition: 0.3s;
}

.option-btn:hover, .solution-button:hover {
    background-color: #2980b9;
}

.option-btn.selected {
    background-color: #2ecc71;
}

.correcta {
    color: green;
    font-weight: bold;
}

.incorrecta {
    color: red;
    font-weight: bold;
}

.ocult { display: none; }
.visible { display: block; }

/* 🌙 Mode fosc */
body.dark-mode {
    background-color: #121212;
    color: #f5f5f5;
}

body.dark-mode #quiz-container {
    background-color: #1e1e1e;
    box-shadow: 0 0 10px rgba(255, 255, 255, 0.05);
}

body.dark-mode select,
body.dark-mode input {
    background-color: #2c2c2c;
    color: #fff;
    border: 1px solid #555;
}

body.dark-mode .option-btn,
body.dark-mode .solution-button {
    background-color: #3b82f6;
}

body.dark-mode header {
    background: #1a1a1a;
}

body.dark-mode #theme-toggle {
    background: #3b82f6;
}

/* 📱 Responsiu */
@media (max-width: 768px) {
    #quiz-container { padding: 15px; }
    select, input { font-size: 14px; }
}