body {
    background: linear-gradient(135deg, #e1f6f7 0%, #f6fcfc 100%);
    min-height: 100vh;
    margin: 0;
    font-family: 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
}

.center-container {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 24px;
}

.quiz-box {
    background: #fff;
    border-radius: 16px;
    box-shadow: 0 8px 32px rgba(66, 146, 150, 0.12);
    padding: 32px;
    max-width: 420px;
    width: 100%;
}

.quiz-title {
    font-size: 2rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 28px;
    color: #429296;
}

.quiz-desc {
    color: #7e9fa2;
    margin-bottom: 16px;
    text-align: center;
}

.quiz-btn {
    display: block;
    width: 100%;
    padding: 14px 0;
    background: #429296;
    color: #fff;
    border: none;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s;
    margin-top: 8px;
    box-shadow: 0 2px 8px rgba(66,146,150,0.08);
    letter-spacing: 1px;
}
.quiz-btn:hover:not(:disabled) {
    background: #316b6d;
}
.quiz-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.quiz-error {
    color: #ef4444;
    font-size: 0.95rem;
    margin-top: 8px;
}

.quiz-question {
    font-size: 1.3rem;
    font-weight: 600;
    color: #233333;
    margin-bottom: 22px;
    min-height: 32px;
}

.quiz-options {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 14px;
    margin-bottom: 32px;
}

.quiz-option-btn {
    padding: 14px 0;
    background: #e1f6f7;
    border: 2px solid #bfe4e7;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    color: #233333;
    cursor: pointer;
    transition: border 0.2s, background 0.2s, color 0.2s;
}
.quiz-option-btn:hover:not(:disabled) {
    border-color: #429296;
    background: #f6fcfc;
    color: #429296;
}
.quiz-option-btn.selected-correct {
    border-color: #22c55e;
    background: #dbfbe7;
    color: #1b7b4b;
}
.quiz-option-btn.selected-wrong {
    border-color: #ef4444;
    background: #fdeeee;
    color: #ef4444;
}
.quiz-option-btn.disabled {
    background: #f6fcfc;
    color: #b0c8ca;
    cursor: not-allowed;
}

.quiz-progress-bar-bg {
    width: 100%;
    height: 8px;
    background: #bfe4e7;
    border-radius: 4px;
    margin-bottom: 24px;
    overflow: hidden;
}
.quiz-progress-bar {
    height: 8px;
    background: #429296;
    transition: width 0.3s;
    border-radius: 4px;
}

.quiz-timer {
    font-size: 1.5rem;
    font-weight: 700;
    color: #429296;
}
.quiz-timer.warning {
    color: #fbbf24;
}
.quiz-timer.urgent {
    color: #ef4444;
}

.quiz-record {
    margin-top: 24px;
    background: #e1f6f7;
    border-radius: 8px;
    padding: 16px 12px;
    max-height: 220px;
    overflow-y: auto;
}
.quiz-record-item {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 1rem;
    margin-bottom: 8px;
}

.quiz-record-item .correct {
    color: #22c55e;
    font-weight: bold;
}
.quiz-record-item .wrong {
    color: #ef4444;
    font-weight: bold;
}

.quiz-score {
    font-size: 2.5rem;
    font-weight: 700;
    color: #429296;
    margin-bottom: 8px;
}

.quiz-finish-title {
    font-size: 1.5rem;
    font-weight: 700;
    color: #316b6d;
    margin-bottom: 12px;
}

/* 统一设置代码块字体为等宽 */
pre, code {
    font-family: 'Fira Mono', 'Consolas', 'Menlo', 'Liberation Mono', 'Courier New', monospace !important;
    font-size: 0.8em;
    background: #f6f8fa;
    color: #222;
}

pre {
    padding: 9px 14px;
    border-radius: 6px;
    margin: 10px 0 3px 0;
    line-height: 1.6;
    overflow-x: auto;
}

@media (max-width: 600px) {
    .quiz-box {
        padding: 18px;
        max-width: 100%;
    }
}