* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Microsoft YaHei', sans-serif;
}

body {
    background-color: #f0f8ff;
    color: #333;
    line-height: 1.6;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 20px;
}

header {
    text-align: center;
    margin-bottom: 30px;
    padding: 20px;
    background: linear-gradient(135deg, #6ab1e7 0%, #2773bb 100%);
    color: white;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

h1 {
    font-size: 28px;
    margin-bottom: 10px;
}

.start-screen {
    text-align: center;
    padding: 40px;
    background: white;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.class-select {
    margin: 30px 0;
}

.class-btn {
    margin: 0 15px 15px;
    padding: 15px 30px;
    font-size: 18px;
    background-color: #4a9fea;
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s;
}

.class-btn:hover {
    background-color: #2c7ac0;
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.exam-standards {
    background-color: #e8f4ff;
    padding: 20px;
    border-radius: 8px;
    margin-top: 30px;
    text-align: left;
    display: inline-block;
}

.exam-standards h3 {
    margin-bottom: 10px;
    color: #2c3e50;
}

.exam-standards ul {
    list-style-type: none;
}

.exam-standards li {
    padding: 5px 0;
    color: #34495e;
}

.screen-hidden {
    display: none;
}

.exam-info {
    display: flex;
    justify-content: space-between;
    margin: 20px 0;
    font-size: 18px;
    font-weight: bold;
    background: white;
    padding: 15px;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
}

.timer {
    color: #e74c3c;
}

.progress-bar {
    height: 10px;
    background-color: #e0e0e0;
    border-radius: 5px;
    margin-bottom: 20px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background-color: #4a9fea;
    width: 0%;
    transition: width 0.3s;
}

.question-container {
    background: white;
    border-radius: 10px;
    padding: 25px;
    margin-bottom: 20px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.05);
}

.question-number {
    font-size: 18px;
    font-weight: bold;
    color: #2c3e50;
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 2px solid #f0f0f0;
}

.question-id {
    font-size: 14px;
    color: #7f8c8d;
    float: right;
}

.question-type {
    font-size: 16px;
    color: #4a9fea;
    margin-bottom: 10px;
    font-weight: bold;
}

.question-text {
    font-size: 18px;
    margin-bottom: 20px;
    font-weight: 500;
    line-height: 1.5;
}

.options {
    margin-left: 10px;
}

.option {
    margin: 12px 0;
    padding: 12px 15px;
    border: 1px solid #e0e0e0;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s;
    position: relative;
}

.option:hover {
    background-color: #f8f9fa;
    border-color: #c0c0c0;
}

.option.selected {
    background-color: #e3f2fd;
    border-color: #2196f3;
}

.option input {
    margin-right: 10px;
}

.navigation {
    display: flex;
    justify-content: space-between;
    margin-top: 30px;
}

.nav-btn {
    padding: 12px 25px;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 16px;
    font-weight: bold;
    transition: all 0.2s;
}

.prev-btn {
    background-color: #7f8c8d;
    color: white;
}

.next-btn {
    background-color: #3498db;
    color: white;
}

.submit-btn {
    background-color: #2ecc71;
    color: white;
}

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

.result-screen {
    text-align: center;
    padding: 40px;
    background: white;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.score-container {
    margin: 30px 0;
}

.score {
    font-size: 72px;
    font-weight: bold;
    color: #4a9fea;
}

.score-text {
    font-size: 18px;
    color: #7f8c8d;
    margin-bottom: 10px;
}

.pass-fail {
    font-size: 24px;
    font-weight: bold;
    padding: 10px 20px;
    border-radius: 30px;
    display: inline-block;
}

.pass {
    background-color: #e8f6ef;
    color: #27ae60;
}

.fail {
    background-color: #fceae9;
    color: #e74c3c;
}

.result-details {
    background-color: #e8f4ff;
    padding: 20px;
    border-radius: 10px;
    margin: 20px 0;
    text-align: left;
    display: inline-block;
}

.result-details p {
    margin: 10px 0;
    font-size: 16px;
}

.wrong-questions {
    text-align: left;
    margin-top: 30px;
    background-color: #fff;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
}

.wrong-title {
    font-size: 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid #f0f0f0;
    margin-bottom: 20px;
    color: #2c3e50;
}

.wrong-item {
    margin-bottom: 25px;
    padding-bottom: 15px;
    border-bottom: 1px solid #f0f0f0;
}

.wrong-item:last-child {
    border-bottom: none;
}

.restart-btn {
    padding: 15px 40px;
    background-color: #4a9fea;
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 18px;
    cursor: pointer;
    margin-top: 30px;
    transition: all 0.3s;
}

.restart-btn:hover {
    background-color: #2c7ac0;
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

/* 改进选项样式，使整个区域可点击 */
.option {
    margin: 10px 0;
    padding: 10px 12px;
    border: 1px solid #e0e0e0;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.2s;
    position: relative;
    display: flex;
    align-items: center;
}

.option:hover {
    background-color: #f0f8ff;
    border-color: #4a9fea;
}

.option.selected {
    background-color: #e3f2fd;
    border-color: #2196f3;
}

.option input {
    position: absolute;
    opacity: 0;
    cursor: pointer;
    z-index: 1; /* 确保输入框在最上层 */
    width: 100%;
    height: 100%;
    left: 0;
    top: 0;
}

.option label {
    cursor: pointer;
    margin: 0;
    padding-left: 28px;
    position: relative;
    width: 100%;
    line-height: 1.4;
    display: flex;
    align-items: center;
    min-height: 18px;
    font-size: 14px;
    pointer-events: none; /* 防止标签干扰点击事件 */
}

.option label:before {
    content: "";
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 16px;
    height: 16px;
    border: 2px solid #ccc;
    background: #fff;
    transition: all 0.2s;
    pointer-events: none; /* 防止伪元素干扰点击事件 */
}

/* 单选按钮 - 圆形 */
.option input[type="radio"] + label:before {
    border-radius: 50%;
}

/* 多选按钮 - 方形 */
.option input[type="checkbox"] + label:before {
    border-radius: 3px;
}

.option input:checked + label:before {
    border-color: #4a9fea;
    background-color: #4a9fea;
}

/* 移除单选按钮的白点 */
.option input[type="radio"]:checked + label:after {
    display: none;
}

/* 简化复选框的对勾样式 */
.option input[type="checkbox"]:checked + label:after {
    content: "✓";
    position: absolute;
    left: 3px;
    top: 50%;
    transform: translateY(-50%);
    color: white;
    font-size: 12px;
    font-weight: bold;
    pointer-events: none; /* 防止伪元素干扰点击事件 */
}

/* 对于多行文本的选项 */
.option.multiline label {
    align-items: flex-start;
}

.option.multiline label:before {
    top: 10px;
    transform: none;
}

.option.multiline input[type="checkbox"]:checked + label:after {
    top: 10px;
    transform: none;
}

/* 增强选中状态的视觉效果 */
.option.selected {
    background-color: #e3f2fd;
    border-color: #2196f3;
    box-shadow: 0 0 0 1px rgba(33, 150, 243, 0.2);
}

footer {
    text-align: center;
    margin-top: 30px;
    color: #7f8c8d;
    font-size: 14px;
}

/* 添加到 style.css 中 */
.wrong-item {
    margin-bottom: 25px;
    padding: 15px;
    background-color: #f9f9f9;
    border-radius: 8px;
    border-left: 4px solid #e74c3c;
}

.wrong-question-number {
    font-weight: bold;
    color: #2c3e50;
    margin-bottom: 10px;
}

.wrong-question-text {
    font-size: 16px;
    margin-bottom: 15px;
    color: #34495e;
}

.wrong-options {
    margin-left: 20px;
    margin-bottom: 15px;
}

.wrong-options div {
    margin: 8px 0;
    padding: 8px;
    background-color: #fff;
    border-radius: 4px;
}

.wrong-answer {
    color: #e74c3c;
    font-weight: bold;
    margin: 10px 0;
}

.correct-answer {
    color: #27ae60;
    font-weight: bold;
}

@media (max-width: 768px) {
    .container {
        padding: 10px;
    }
    
    .class-btn {
        display: block;
        margin: 15px auto;
        width: 80%;
    }
    
    .exam-info {
        flex-direction: column;
        gap: 10px;
    }
    
    .navigation {
        flex-direction: column;
        gap: 10px;
    }
    
    .nav-btn {
        width: 100%;
        margin: 5px 0;
    }
}