/* 
 * 优学家教网站主要样式文件
 * 实现现代化、科技感的UI设计
 */

/* 基础重置和变量定义 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* 主色调 */
    --primary-color: #2c5ae0;
    --primary-dark: #1e3eb8;
    --primary-light: #4d7aff;
    
    /* 辅助色 */
    --secondary-color: #00d2ff;
    --accent-color: #ff6b35;
    --success-color: #00c851;
    
    /* 中性色 */
    --dark-bg: #0a0e27;
    --dark-secondary: #1a1f3a;
    --gray-100: #f8f9fa;
    --gray-200: #e9ecef;
    --gray-300: #dee2e6;
    --gray-400: #ced4da;
    --gray-600: #6c757d;
    --gray-800: #343a40;
    --gray-900: #212529;
    
    /* 渐变 */
    --gradient-primary: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    --gradient-dark: linear-gradient(135deg, var(--dark-bg), var(--dark-secondary));
    --gradient-accent: linear-gradient(135deg, var(--accent-color), #ff8a65);
    
    /* 阴影 */
    --shadow-sm: 0 2px 4px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 16px rgba(0,0,0,0.15);
    --shadow-lg: 0 8px 32px rgba(0,0,0,0.2);
    --shadow-xl: 0 16px 64px rgba(0,0,0,0.25);
    
    /* 动画时长 */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
    
    /* 字体 */
    --font-primary: 'Microsoft YaHei', 'PingFang SC', 'Helvetica Neue', Arial, sans-serif;
    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-bold: 700;
}

/* 基础样式 */
html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-primary);
    line-height: 1.6;
    color: var(--gray-800);
    background-color: #ffffff;
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 导航栏样式 */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-sm);
    z-index: 1000;
    transition: var(--transition-normal);
}

.navbar.scrolled {
    background: rgba(255, 255, 255, 0.98);
    box-shadow: var(--shadow-md);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-logo h2 {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    font-weight: var(--font-weight-bold);
    font-size: 1.8rem;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-link {
    text-decoration: none;
    color: var(--gray-700);
    font-weight: var(--font-weight-medium);
    position: relative;
    transition: var(--transition-fast);
    padding: 0.5rem 0;
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary-color);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient-primary);
    transition: var(--transition-normal);
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

/* 汉堡菜单 */
.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.hamburger .bar {
    width: 25px;
    height: 3px;
    background-color: var(--gray-800);
    margin: 3px 0;
    transition: var(--transition-fast);
}

/* 主页横幅 */
.hero {
    height: 100vh;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    background: var(--gradient-dark);
}

.hero-background {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
  
}

/* 教学场景背景层 */
.hero-background::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: url(../image/top_bg.png);
    background-size: 
        100% 100%, 100% 100%, 100% 100%, 
        200px 100px, 200px 100px, 200px 100px, 200px 100px;
    opacity: 0.8;
}


@keyframes educationFloat {
    0%, 100% { 
        transform: translateY(0px) translateX(0px);
        opacity: 0.7;
    }
    25% { 
        transform: translateY(-5px) translateX(2px);
        opacity: 0.8;
    }
    50% { 
        transform: translateY(-10px) translateX(-2px);
        opacity: 0.6;
    }
    75% { 
        transform: translateY(-5px) translateX(1px);
        opacity: 0.9;
    }
}



@keyframes float {
    0%, 100% { transform: translateY(0px) rotate(0deg); }
    50% { transform: translateY(-20px) rotate(1deg); }
}

.hero-content {
    text-align: center;
    color: white;
    z-index: 2;
    max-width: 800px;
    padding: 0 20px;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: var(--font-weight-bold);
    margin-bottom: 1rem;
    background: linear-gradient(135deg, #ffffff, #e3f2fd);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: fadeInUp 1s ease-out;
}

.hero-subtitle {
    font-size: 1.5rem;
    margin-bottom: 3rem;
    opacity: 0.9;
    animation: fadeInUp 1s ease-out 0.2s both;
}

.hero-features {
    display: flex;
    justify-content: center;
    gap: 3rem;
    margin-bottom: 3rem;
    animation: fadeInUp 1s ease-out 0.4s both;
}

.feature-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
}

.feature-icon {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.cta-button {
    background: var(--gradient-primary);
    color: white;
    border: none;
    padding: 1rem 2.5rem;
    font-size: 1.2rem;
    font-weight: var(--font-weight-medium);
    border-radius: 50px;
    cursor: pointer;
    transition: var(--transition-normal);
    box-shadow: var(--shadow-md);
    animation: fadeInUp 1s ease-out 0.6s both;
}

.cta-button:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

/* 动画定义 */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* 通用章节样式 */
.section-title {
    font-size: 2.5rem;
    font-weight: var(--font-weight-bold);
    text-align: center;
    margin-bottom: 1rem;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.section-subtitle {
    text-align: center;
    font-size: 1.2rem;
    color: var(--gray-600);
    margin-bottom: 3rem;
}

/* 服务优势样式 */
.advantages {
    padding: 100px 0;
    background: var(--gray-100);
}

.advantages-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.advantage-card {
    background: white;
    padding: 2.5rem 2rem;
    border-radius: 20px;
    text-align: center;
    box-shadow: var(--shadow-sm);
    transition: var(--transition-normal);
    position: relative;
    overflow: hidden;
}

.advantage-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: var(--gradient-primary);
}

.advantage-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-lg);
}

/* 现代化图标样式 */
.feature-icon,
.card-icon,
.contact-icon {
    width: 60px;
    height: 60px;
    background: var(--gradient-primary);
    border-radius: 15px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    transition: var(--transition-normal);
    position: relative;
    overflow: hidden;
}

.feature-icon svg,
.card-icon svg,
.contact-icon svg {
    width: 30px;
    height: 30px;
    stroke-width: 2.5;
    filter: drop-shadow(0 2px 4px rgba(0,0,0,0.2));
}

.feature-icon::before,
.card-icon::before,
.contact-icon::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
    transition: var(--transition-slow);
}

.feature-icon:hover::before,
.card-icon:hover::before,
.contact-icon:hover::before {
    left: 100%;
}

.feature-icon:hover,
.card-icon:hover,
.contact-icon:hover {
    transform: translateY(-5px) scale(1.05);
    box-shadow: var(--shadow-lg);
}

/* 特殊的3D效果 */
.feature-icon[data-icon="target"] {
    background: linear-gradient(135deg, #ff6b35, #ff8a65);
}

.feature-icon[data-icon="teacher"] {
    background: linear-gradient(135deg, #2c5ae0, #4d7aff);
}

.feature-icon[data-icon="growth"] {
    background: linear-gradient(135deg, #00d2ff, #00c851);
}

.card-icon[data-icon="trophy"] {
    background: linear-gradient(135deg, #ffd700, #ffb300);
}

.card-icon[data-icon="personalized"] {
    background: linear-gradient(135deg, #9c27b0, #e91e63);
}

.card-icon[data-icon="analytics"] {
    background: linear-gradient(135deg, #00bcd4, #009688);
}

.card-icon[data-icon="support"] {
    background: linear-gradient(135deg, #4caf50, #8bc34a);
}

.advantage-card h3 {
    font-size: 1.5rem;
    font-weight: var(--font-weight-bold);
    margin-bottom: 1rem;
    color: var(--gray-800);
}

.advantage-card p {
    color: var(--gray-600);
    line-height: 1.6;
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% {
        transform: translateY(0);
    }
    40% {
        transform: translateY(-10px);
    }
    60% {
        transform: translateY(-5px);
    }
}

/* 师资团队样式 */
.teachers {
    padding: 100px 0;
    background: white;
}

.teachers-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.teacher-card {
    background: white;
    border-radius: 20px;
    padding: 2rem;
    text-align: center;
    box-shadow: var(--shadow-md);
    transition: var(--transition-normal);
    position: relative;
    overflow: hidden;
}

.teacher-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--gradient-primary);
    opacity: 0;
    transition: var(--transition-normal);
    z-index: 1;
}

.teacher-card:hover::before {
    opacity: 0.1;
}

.teacher-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-xl);
}

.teacher-avatar {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    background: var(--gradient-primary);
    margin: 0 auto 1.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 3rem;
    position: relative;
    z-index: 2;
}

.teacher-info {
    position: relative;
    z-index: 2;
}

.teacher-info h3 {
    font-size: 1.5rem;
    font-weight: var(--font-weight-bold);
    margin-bottom: 0.5rem;
    color: var(--gray-800);
}

.teacher-subject {
    color: var(--primary-color);
    font-weight: var(--font-weight-medium);
    margin-bottom: 1rem;
}

.teacher-desc {
    color: var(--gray-600);
    line-height: 1.6;
}

/* 课程体系样式 */
.courses {
    padding: 100px 0;
    background: var(--gray-100);
}

.courses-tabs {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 3rem;
}

.tab-button {
    background: white;
    border: 2px solid var(--gray-300);
    padding: 1rem 2rem;
    border-radius: 50px;
    cursor: pointer;
    transition: var(--transition-normal);
    font-weight: var(--font-weight-medium);
    color: var(--gray-600);
}

.tab-button.active,
.tab-button:hover {
    background: var(--gradient-primary);
    border-color: transparent;
    color: white;
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.course-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.course-card {
    background: white;
    padding: 2rem;
    border-radius: 15px;
    box-shadow: var(--shadow-sm);
    transition: var(--transition-normal);
    border-left: 4px solid var(--primary-color);
}

.course-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}

.course-card h4 {
    color: var(--gray-800);
    font-weight: var(--font-weight-bold);
    margin-bottom: 1rem;
}

.course-card p {
    color: var(--gray-600);
    line-height: 1.6;
}

/* 服务流程样式 */
.process {
    padding: 100px 0;
    background: white;
}

.process-steps {
    display: flex;
    justify-content: center;
    align-items: flex-start;
    gap: 2rem;
    margin-top: 3rem;
    flex-wrap: wrap;
}

.step {
    text-align: center;
    max-width: 280px;
    position: relative;
}

.step:not(:last-child)::after {
    content: '→';
    position: absolute;
    top: 40px;
    right: -1.5rem;
    color: var(--primary-color);
    font-size: 1.5rem;
    font-weight: bold;
}

.step-number {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    background: var(--gradient-primary);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    font-weight: var(--font-weight-bold);
    margin: 0 auto 1.5rem;
    box-shadow: var(--shadow-md);
    animation: pulse 2s infinite;
}

/* 为每个步骤数字设置不同的颜色 */
.step:nth-child(1) .step-number {
    background: linear-gradient(135deg, #ff6b35, #ff8a65); /* 红橙色 */
}

.step:nth-child(2) .step-number {
    background: linear-gradient(135deg, #2c5ae0, #4d7aff); /* 蓝色 */
}

.step:nth-child(3) .step-number {
    background: linear-gradient(135deg, #00d2ff, #00c851); /* 青绿色 */
}

.step:nth-child(4) .step-number {
    background: linear-gradient(135deg, #9c27b0, #e91e63); /* 紫红色 */
}

.step:nth-child(5) .step-number {
    background: linear-gradient(135deg, #ffd700, #ff9800); /* 金黄色 */
}

@keyframes pulse {
    0% {
        box-shadow: var(--shadow-md), 0 0 0 0 rgba(44, 90, 224, 0.7);
    }
    70% {
        box-shadow: var(--shadow-md), 0 0 0 10px rgba(44, 90, 224, 0);
    }
    100% {
        box-shadow: var(--shadow-md), 0 0 0 0 rgba(44, 90, 224, 0);
    }
}

.step h3 {
    color: var(--gray-800);
    font-weight: var(--font-weight-bold);
    margin-bottom: 1rem;
}

.step p {
    color: var(--gray-600);
    line-height: 1.6;
}

/* 成功案例样式 */
.cases {
    padding: 100px 0;
    background: var(--gray-100);
}

.cases-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.case-card {
    background: white;
    padding: 2.5rem;
    border-radius: 20px;
    box-shadow: var(--shadow-md);
    transition: var(--transition-normal);
    position: relative;
    overflow: hidden;
}

.case-card::before {
    content: '"';
    position: absolute;
    top: -10px;
    left: 20px;
    font-size: 6rem;
    color: var(--primary-color);
    opacity: 0.2;
    font-family: serif;
}

.case-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-lg);
}

.case-content {
    position: relative;
    z-index: 2;
}

.case-quote {
    font-style: italic;
    color: var(--gray-600);
    line-height: 1.6;
    margin-bottom: 2rem;
}

.case-student {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.student-avatar {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: var(--gradient-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: var(--font-weight-bold);
}

.student-info h4 {
    color: var(--gray-800);
    font-weight: var(--font-weight-bold);
    margin-bottom: 0.25rem;
}

.student-grade {
    color: var(--gray-600);
    font-size: 0.9rem;
}

/* 常见问题解答样式 */
.faq {
    padding: 100px 0;
    background: white;
    position: relative;
}

.faq::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: 
        radial-gradient(circle at 10% 20%, rgba(44, 90, 224, 0.05) 0%, transparent 50%),
        radial-gradient(circle at 90% 80%, rgba(0, 210, 255, 0.05) 0%, transparent 50%);
    pointer-events: none;
}

.faq-container {
    max-width: 800px;
    margin: 0 auto;
    position: relative;
    z-index: 2;
}

.faq-item {
    background: white;
    border-radius: 15px;
    margin-bottom: 1.5rem;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--gray-200);
    transition: var(--transition-normal);
    overflow: hidden;
}

.faq-item:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.faq-item.active {
    border-color: var(--primary-color);
    box-shadow: 0 4px 20px rgba(44, 90, 224, 0.15);
}

.faq-question {
    display: flex;
    align-items: center;
    padding: 1.5rem 2rem;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    background: linear-gradient(135deg, #ffffff, #f8f9fa);
    justify-content: space-between;
    border-radius: 15px 15px 0 0;
}

.faq-question:hover {
    background: linear-gradient(135deg, #f8f9fa, #e9ecef);
    transform: translateY(-1px);
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.faq-item.active .faq-question {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
    color: white;
    transform: translateY(0);
    box-shadow: 0 4px 16px rgba(44, 90, 224, 0.3);
}

.faq-question h3 {
    flex: 1;
    font-size: 1.2rem;
    font-weight: var(--font-weight-medium);
    color: var(--gray-800);
    margin: 0;
    line-height: 1.4;
}

.faq-item.active .faq-question h3 {
    color: white;
}

.faq-toggle {
    width: 30px;
    height: 30px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    flex-shrink: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.1);
}

.faq-toggle svg {
    width: 20px;
    height: 20px;
    stroke: var(--gray-600);
    stroke-width: 2;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.faq-item.active .faq-toggle {
    background: rgba(255, 255, 255, 0.2);
    transform: scale(1.1);
}

.faq-item.active .faq-toggle svg {
    stroke: white;
    transform: rotate(180deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: all 0.5s cubic-bezier(0.4, 0, 0.2, 1);
    background: #ffffff;
    transform: translateY(-10px);
    opacity: 0;
}

.faq-item.active .faq-answer {
    max-height: 400px;
    padding: 0 2rem 2rem 2rem;
    transform: translateY(0);
    opacity: 1;
    transition: all 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.faq-answer p {
    color: var(--gray-700);
    line-height: 1.8;
    margin: 0;
    font-size: 0.95rem;
}

/* FAQ动画效果 */
.faq-item {
    opacity: 0;
    transform: translateY(20px);
    animation: fadeInUp 0.6s ease forwards;
}

.faq-item:nth-child(1) { animation-delay: 0.1s; }
.faq-item:nth-child(2) { animation-delay: 0.2s; }
.faq-item:nth-child(3) { animation-delay: 0.3s; }
.faq-item:nth-child(4) { animation-delay: 0.4s; }
.faq-item:nth-child(5) { animation-delay: 0.5s; }
.faq-item:nth-child(6) { animation-delay: 0.6s; }

/* 联系我们样式 */
.contact {
    padding: 100px 0;
    background: white;
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    margin-top: 3rem;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    padding: 2rem;
    background: var(--gray-100);
    border-radius: 15px;
    transition: var(--transition-normal);
}

.contact-item:hover {
    transform: translateX(10px);
    box-shadow: var(--shadow-md);
}

.contact-icon {
    font-size: 2rem;
    width: 60px;
    height: 60px;
    background: var(--gradient-primary);
    border-radius: 15px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.contact-item h4 {
    color: var(--gray-800);
    font-weight: var(--font-weight-bold);
    margin-bottom: 0.5rem;
}

.contact-item p {
    color: var(--gray-600);
}

.contact-form {
    background: var(--gray-100);
    padding: 2.5rem;
    border-radius: 20px;
}

.contact-form h3 {
    color: var(--gray-800);
    font-weight: var(--font-weight-bold);
    margin-bottom: 2rem;
    text-align: center;
}

.contact-form input,
.contact-form select,
.contact-form textarea {
    width: 100%;
    padding: 1rem;
    margin-bottom: 1.5rem;
    border: 2px solid var(--gray-300);
    border-radius: 10px;
    font-family: inherit;
    transition: var(--transition-fast);
    background: white;
}

.contact-form input:focus,
.contact-form select:focus,
.contact-form textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(44, 90, 224, 0.1);
}

.submit-btn {
    width: 100%;
    background: var(--gradient-primary);
    color: white;
    border: none;
    padding: 1rem;
    border-radius: 10px;
    font-weight: var(--font-weight-medium);
    cursor: pointer;
    transition: var(--transition-normal);
}

.submit-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

/* 页脚样式 */
.footer {
    background: var(--dark-bg);
    color: white;
    padding: 3rem 0 1rem;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h4 {
    color: var(--secondary-color);
    margin-bottom: 1rem;
    font-weight: var(--font-weight-bold);
}

.footer-section ul {
    list-style: none;
}

.footer-section ul li {
    margin-bottom: 0.5rem;
}

.footer-section a {
    color: var(--gray-300);
    text-decoration: none;
    transition: var(--transition-fast);
}

.footer-section a:hover {
    color: var(--secondary-color);
}

/* 二维码样式 */
.qr-codes {
    text-align: center;
}

.qr-container {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-top: 1rem;
}

.qr-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
}

.qr-code {
    width: 120px;
    height: 120px;
    background: white;
    border-radius: 10px;
    padding: 5px;
    box-shadow: var(--shadow-md);
    transition: var(--transition-normal);
    position: relative;
    overflow: hidden;
}

.qr-code:hover {
    transform: scale(1.1);
    box-shadow: var(--shadow-lg);
}

.qr-placeholder {
    width: 100%;
    height: 100%;
    border-radius: 5px;
}

.qr-item span {
    font-size: 0.8rem;
    color: var(--gray-300);
    font-weight: var(--font-weight-medium);
}

/* 二维码动画效果 */
.qr-code::after {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(44, 90, 224, 0.1), transparent);
    transition: var(--transition-slow);
}

.qr-code:hover::after {
    left: 100%;
}

.footer-bottom {
    border-top: 1px solid var(--gray-600);
    padding-top: 1rem;
    text-align: center;
    color: var(--gray-400);
}

/* 返回顶部按钮 */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: var(--gradient-primary);
    color: white;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    font-size: 1.5rem;
    box-shadow: var(--shadow-md);
    transition: var(--transition-normal);
    opacity: 0;
    visibility: hidden;
    z-index: 1000;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

/* 工具类 */
.text-center { text-align: center; }
.text-primary { color: var(--primary-color); }
.bg-primary { background: var(--gradient-primary); }
.hidden { display: none; }
.visible { display: block; }