:root {
    --bg-primary: #f5f0e6;
    --bg-card: #fffef9;
    --text-primary: #5d4e37;
    --text-secondary: #8b7355;
    --accent: #c94c4c;
    --border: #d4c5a9;
    --success: #4a7c59;
    --error: #c94c4c;
    --shadow: rgba(93, 78, 55, 0.1);
}

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

body {
    font-family: 'Microsoft YaHei', 'PingFang SC', sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    padding: 20px;
    background-image: 
        radial-gradient(circle at 20% 80%, rgba(201, 76, 76, 0.05) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(74, 124, 89, 0.05) 0%, transparent 50%);
}

.container {
    max-width: 600px;
    margin: 0 auto;
}

.header {
    text-align: center;
    padding: 20px 0;
    margin-bottom: 20px;
}

.header h1 {
    font-family: 'KaiTi', 'STKaiti', '楷体', serif;
    font-size: 28px;
    font-weight: normal;
    color: var(--text-primary);
    margin-bottom: 8px;
    letter-spacing: 4px;
}

.stats {
    display: flex;
    justify-content: center;
    gap: 20px;
    font-size: 14px;
    color: var(--text-secondary);
}

.stats span {
    display: flex;
    align-items: center;
    gap: 4px;
}

.stats .correct {
    color: var(--success);
}

.navigation {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 20px;
    padding: 12px;
    background: var(--bg-card);
    border-radius: 12px;
    border: 1px solid var(--border);
}

.nav-btn {
    width: 36px;
    height: 36px;
    border: 1px solid var(--border);
    background: var(--bg-card);
    color: var(--text-secondary);
    border-radius: 8px;
    cursor: pointer;
    font-size: 14px;
    transition: all 0.3s ease;
}

.nav-btn:hover {
    background: var(--bg-primary);
    border-color: var(--accent);
    color: var(--accent);
}

.nav-btn.active {
    background: var(--accent);
    color: white;
    border-color: var(--accent);
}

.card {
    background: var(--bg-card);
    border-radius: 16px;
    border: 1px solid var(--border);
    padding: 30px;
    margin-bottom: 20px;
    box-shadow: 0 4px 20px var(--shadow);
    position: relative;
    overflow: hidden;
}

.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--accent), var(--success));
}

.question-number {
    position: absolute;
    top: 20px;
    right: 20px;
    font-size: 12px;
    color: var(--text-secondary);
    background: var(--bg-primary);
    padding: 4px 12px;
    border-radius: 20px;
}

.question {
    font-family: 'KaiTi', 'STKaiti', '楷体', serif;
    font-size: 22px;
    line-height: 1.8;
    text-align: center;
    margin-bottom: 30px;
    padding: 20px;
    background: linear-gradient(135deg, rgba(212, 197, 169, 0.2), transparent);
    border-radius: 12px;
    border-left: 3px solid var(--accent);
}

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

.option-btn {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px 20px;
    background: var(--bg-card);
    border: 2px solid var(--border);
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.3s ease;
    text-align: left;
    font-size: 16px;
    color: var(--text-primary);
}

.option-btn:hover {
    border-color: var(--accent);
    transform: translateX(4px);
    box-shadow: 0 2px 10px var(--shadow);
}

.option-btn.selected {
    border-color: var(--accent);
    background: rgba(201, 76, 76, 0.05);
}

.option-btn.correct {
    border-color: var(--success);
    background: rgba(74, 124, 89, 0.1);
}

.option-btn.wrong {
    border-color: var(--error);
    background: rgba(201, 76, 76, 0.1);
}

.option-num {
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-primary);
    border-radius: 6px;
    font-weight: bold;
    font-size: 14px;
    color: var(--text-secondary);
    flex-shrink: 0;
}

.option-btn:hover .option-num {
    background: var(--accent);
    color: white;
}

.option-btn.selected .option-num {
    background: var(--accent);
    color: white;
}

.option-btn.correct .option-num {
    background: var(--success);
    color: white;
}

.option-btn.wrong .option-num {
    background: var(--error);
    color: white;
}

.hint-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    margin-top: 20px;
    padding: 12px;
    background: transparent;
    border: 1px dashed var(--border);
    border-radius: 12px;
    cursor: pointer;
    color: var(--text-secondary);
    font-size: 14px;
    transition: all 0.3s ease;
    width: 100%;
}

.hint-btn:hover {
    border-color: var(--accent);
    color: var(--accent);
    background: rgba(201, 76, 76, 0.05);
}

.details {
    background: var(--bg-card);
    border-radius: 12px;
    border: 1px solid var(--border);
    padding: 20px;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
}

.detail-item {
    text-align: center;
    padding: 12px;
    background: var(--bg-primary);
    border-radius: 8px;
}

.detail-label {
    font-size: 12px;
    color: var(--text-secondary);
    margin-bottom: 4px;
}

.detail-value {
    font-size: 16px;
    color: var(--text-primary);
    font-weight: 500;
}

.feedback {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) scale(0.8);
    background: var(--bg-card);
    border-radius: 16px;
    padding: 30px 50px;
    text-align: center;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
}

.feedback.show {
    opacity: 1;
    visibility: visible;
    transform: translate(-50%, -50%) scale(1);
}

.feedback.correct {
    border: 2px solid var(--success);
}

.feedback.wrong {
    border: 2px solid var(--error);
}

.feedback-icon {
    font-size: 48px;
    margin-bottom: 12px;
}

.feedback-text {
    font-size: 18px;
    color: var(--text-primary);
}

.overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.3);
    z-index: 999;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
}

.overlay.show {
    opacity: 1;
    visibility: visible;
}

.hint-message {
    background: var(--bg-card);
    border-radius: 12px;
    border: 1px solid var(--accent);
    padding: 16px;
    margin-top: 16px;
    font-size: 14px;
    color: var(--text-primary);
    line-height: 1.6;
    display: none;
}

.hint-message.show {
    display: block;
    animation: fadeIn 0.3s ease;
}

.loading {
    text-align: center;
    padding: 40px;
    color: var(--text-secondary);
}

.loading::after {
    content: '';
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 2px solid var(--border);
    border-top-color: var(--accent);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
    margin-left: 10px;
    vertical-align: middle;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-10px); }
    to { opacity: 1; transform: translateY(0); }
}

.error-message {
    text-align: center;
    padding: 20px;
    color: var(--error);
}

.retry-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    margin-top: 12px;
    padding: 10px 20px;
    background: var(--accent);
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 14px;
    transition: all 0.3s ease;
}

.retry-btn:hover {
    opacity: 0.9;
    transform: translateY(-2px);
}

.nav-btn.random {
    background: linear-gradient(135deg, var(--accent), #e67e22);
    color: white;
    border: none;
    min-width: 60px;
}

.nav-btn.random:hover {
    transform: scale(1.05);
    box-shadow: 0 2px 10px rgba(201, 76, 76, 0.3);
}

.footer {
    text-align: center;
    padding: 20px;
    margin-top: 20px;
}

.contact-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 24px;
    background: linear-gradient(135deg, var(--accent), #e67e22);
    color: white;
    border: none;
    border-radius: 25px;
    cursor: pointer;
    font-size: 14px;
    transition: all 0.3s ease;
    text-decoration: none;
}

.contact-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(201, 76, 76, 0.4);
}

@media (max-width: 480px) {
    body {
        padding: 12px;
    }

    .header h1 {
        font-size: 24px;
    }

    .card {
        padding: 20px;
    }

    .question {
        font-size: 18px;
        padding: 16px;
    }

    .details {
        grid-template-columns: 1fr 1fr;
        gap: 10px;
    }

    .detail-item {
        padding: 10px;
    }
}