:root {
    --primary-color: #4a90e2;
    --success-color: #2ecc71;
    --error-color: #e74c3c;
    --warning-color: #f39c12;
    --text-color: #333;
    --bg-color: #f5f7fa;
    --card-bg: #ffffff;
    --border-radius: 8px;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    display: flex;
    justify-content: center;
    min-height: 100vh;
    padding: 20px;
}

.container {
    width: 100%;
    max-width: 600px;
    margin-top: 40px;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

h1 {
    font-size: 24px;
    color: var(--primary-color);
}

.stats {
    font-size: 14px;
    color: #666;
    display: flex;
    gap: 15px;
}

.card {
    background: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 30px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.question-header {
    margin-bottom: 15px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.badge {
    background: #eee;
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 12px;
    font-weight: bold;
    color: #555;
}

.mode-indicator {
    background-color: var(--warning-color);
    color: white;
    padding: 8px 15px;
    border-radius: var(--border-radius);
    margin-bottom: 15px;
    text-align: center;
    font-weight: bold;
}

.question-text {
    font-size: 18px;
    font-weight: 500;
    margin-bottom: 25px;
}

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

.option-item {
    padding: 12px 16px;
    border: 2px solid #eee;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    align-items: center;
}

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

.option-item.selected {
    border-color: var(--primary-color);
    background-color: #e6f0fa;
}

.option-item.correct {
    border-color: var(--success-color);
    background-color: #eafaf1;
    color: #006400;
}

.option-item.wrong {
    border-color: var(--error-color);
    background-color: #fdedec;
    color: #8b0000;
}

.option-key {
    font-weight: bold;
    margin-right: 10px;
    width: 24px;
}

.feedback {
    margin-top: 20px;
    padding: 15px;
    border-radius: var(--border-radius);
    background-color: #f8f9fa;
    border-left: 4px solid transparent;
}

.feedback.correct {
    border-left-color: var(--success-color);
    background-color: #eafaf1;
}

.feedback.wrong {
    border-left-color: var(--error-color);
    background-color: #fdedec;
}

.hidden {
    display: none;
}

.controls {
    margin-top: 30px;
    display: flex;
    justify-content: flex-end;
    gap: 10px;
}

.btn {
    padding: 10px 20px;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 16px;
    font-weight: bold;
    transition: background 0.2s;
}

.btn-small {
    padding: 5px 10px;
    font-size: 12px;
    background-color: #eee;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    color: #666;
}

.btn-small:hover {
    background-color: #ddd;
    color: #333;
}

.btn.primary {
    background-color: var(--primary-color);
    color: white;
}

.btn.primary:hover {
    background-color: #357abd;
}

.btn.secondary {
    background-color: white;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
}

.btn.secondary:hover {
    background-color: #f0f7ff;
}