:root {
    --primary-color: #2c3e50;
    --accent-color: #3498db;
    --error-color: #e74c3c;
    --bg-color: #f4f7f6;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
}

.quiz-container {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.1);
    max-width: 600px;
    width: 90%;
}

header {
    text-align: right;
    color: #888;
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

h2 {
    color: var(--primary-color);
    line-height: 1.4;
    margin-bottom: 1.5rem;
}

.options-grid {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.option-card {
    display: flex;
    align-items: center;
    padding: 15px;
    border: 2px solid #eee;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s ease;
}

.option-card:hover {
    border-color: var(--accent-color);
    background-color: #f0f7ff;
}

.option-card input {
    margin-right: 15px;
    transform: scale(1.2);
}

.error-message {
    color: var(--error-color);
    background: #fdf2f2;
    padding: 10px;
    border-radius: 5px;
    font-weight: bold;
    border-left: 4px solid var(--error-color);
}

.submit-btn {
    margin-top: 2rem;
    width: 100%;
    padding: 12px;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 1.1rem;
    font-weight: bold;
    cursor: pointer;
}

.submit-btn:hover {
    background-color: #1a252f;
}