/* 全局样式重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* 基础变量 */
:root {
    --primary-color: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #60a5fa;
    --secondary-color: #f97316;
    --secondary-dark: #ea580c;
    --accent-color: #10b981;
    --text-color: #1e293b;
    --text-light: #64748b;
    --bg-color: #ffffff;
    --bg-light: #f8fafc;
    --bg-dark: #e2e8f0;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 1rem;
    --container-width: 1200px;
    --header-height: 80px;
    --font-main: 'PingFang SC', 'Microsoft YaHei', sans-serif;
}

/* 基础样式 */
body {
    font-family: var(--font-main);
    color: var(--text-color);
    line-height: 1.6;
    background-color: var(--bg-color);
}

img {
    max-width: 100%;
    height: auto;
}

a {
    text-decoration: none;
    color: var(--primary-color);
    transition: color 0.3s ease;
}

a:hover {
    color: var(--primary-dark);
}

a:focus {
    outline: none;
    box-shadow: none;
}

ul, ol {
    list-style: none;
}

/* 容器 */
.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* 按钮样式 */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius-md);
    font-weight: 600;
    cursor: pointer;
    text-align: center;
    transition: all 0.3s ease;
}

.btn.primary {
    background-color: var(--primary-color);
    color: white;
    border: 1px solid var(--primary-color);
}

.btn.primary:hover {
    background-color: var(--primary-dark);
    border-color: var(--primary-dark);
}

.btn.secondary {
    background-color: white;
    color: var(--primary-color);
    border: 1px solid var(--primary-color);
}

.btn.secondary:hover {
    background-color: var(--bg-light);
}

.btn.text {
    background-color: transparent;
    color: var(--primary-color);
    padding: 0.25rem 0;
    border: none;
}

.btn.text:hover {
    color: var(--primary-dark);
}

/* 标题样式 */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    margin-bottom: 1rem;
    line-height: 1.3;
}

.section-title {
    font-size: 2rem;
    text-align: center;
    margin-bottom: 1rem;
}

.section-desc {
    text-align: center;
    color: var(--text-light);
    font-size: 1.1rem;
    margin-bottom: 3rem;
}

/* 页面结构 */
section {
    padding: 5rem 0;
}

/* 导航栏 */
.header {
    position: sticky;
    top: 0;
    background-color: white;
    box-shadow: var(--shadow-sm);
    z-index: 100;
    height: var(--header-height);
    display: flex;
    align-items: center;
}

.header .container {
    display: flex;
    align-items: center;
    width: 100%;
}

.logo {
    margin-right: auto;
    margin-left: 40px;
}

.logo h1 {
    font-size: 1.7rem;
    margin-bottom: 0;
    font-weight: 700;
}

.logo .logo-container {
    height: calc(var(--header-height) - 20px) !important;
    width: auto;
    display: flex;
    align-items: center;
    justify-content: flex-start;
    padding: 10px 0;
    max-width: 300px;
}

.logo .logo-container img {
    height: calc(var(--header-height) * 0.7) !important;
    width: auto !important;
    max-height: calc(var(--header-height) * 0.7) !important;
    object-fit: contain;
    margin-right: 20px;
}

.logo .logo-container .logo-text {
    font-size: 1.7rem;
    font-weight: 700;
    color: #1e40af;
    white-space: nowrap;
}

/* 额外的强制样式确保logo大小 */
.header .logo a .logo-container {
    height: var(--header-height) !important;
    padding: 0px 0;
}

.header .logo a .logo-container img {
    height: calc(var(--header-height) * 0.7) !important;
    width: auto !important;
    max-width: 300px !important;
}

.nav {
    margin-left: auto;
}

.nav ul {
    display: flex;
    gap: 3rem;
}

.nav a {
    color: var(--text-color);
    font-weight: 500;
    position: relative;
    padding: 0.5rem 0;
}

.nav a:after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: 0;
    left: 0;
    background-color: var(--primary-color);
    transition: width 0.3s ease;
}

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

.nav a.active {
    color: var(--primary-color);
}

.user-actions {
    display: flex;
    gap: 1rem;
}

/* 英雄区域 */
.hero {
    background-color: var(--bg-light);
    padding: 6rem 0;
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    align-items: center;
}

.hero-content h2 {
    font-size: 2.5rem;
    margin-bottom: 1.5rem;
}

.hero-content p {
    font-size: 1.2rem;
    color: var(--text-light);
    margin-bottom: 2rem;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
}

/* 添加edu_img样式 */
.edu_img {
    display: flex;
    justify-content: center;
    align-items: center;
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
}

.edu_img img {
    width: 100%;
    height: auto;
    transition: transform 0.5s ease;
    object-fit: cover;
}

.edu_img img:hover {
    transform: scale(1.05);
}

/* 特色功能 */
.features-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 2rem;
    margin-top: 3rem;
}

.feature-card {
    background-color: white;
    border-radius: var(--radius-md);
    padding: 2rem;
    box-shadow: var(--shadow-md);
    text-align: center;
    transition: transform 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-5px);
}

.feature-icon {
    margin-bottom: 1.5rem;
}

.feature-icon img {
    width: 64px;
    height: 64px;
}

.feature-card h3 {
    margin-bottom: 1rem;
}

.feature-card p {
    color: var(--text-light);
}

/* 课程预览 */
.courses-preview {
    background-color: var(--bg-light);
}

.courses-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
    margin-bottom: 3rem;
}

.course-card {
    background-color: white;
    border-radius: var(--radius-md);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: transform 0.3s ease;
}

.course-card:hover {
    transform: translateY(-5px);
}

.course-image {
    position: relative;
    height: 200px;
    overflow: hidden;
}

.course-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.course-tag {
    position: absolute;
    top: 1rem;
    left: 1rem;
    background-color: var(--primary-color);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: var(--radius-sm);
    font-size: 0.8rem;
    font-weight: 600;
}

.course-content {
    padding: 1.5rem;
}

.course-content h3 {
    margin-bottom: 0.5rem;
}

.course-content p {
    color: var(--text-light);
    margin-bottom: 1rem;
}

.courses-action {
    text-align: center;
}

/* 实验室预览 */
.lab-preview .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    align-items: center;
}

.lab-content h2 {
    margin-bottom: 1.5rem;
    text-align: left;
}

.lab-content p {
    margin-bottom: 2rem;
}

.lab-features {
    margin-bottom: 2rem;
}

.lab-features li {
    margin-bottom: 0.5rem;
    padding-left: 1.5rem;
    position: relative;
}

.lab-features li:before {
    content: '✓';
    color: var(--accent-color);
    position: absolute;
    left: 0;
    font-weight: bold;
}

/* 用户评价 */
.testimonials {
    background-color: var(--bg-light);
}

.testimonials-slider {
    display: flex;
    gap: 2rem;
    margin-top: 3rem;
}

.testimonial-card {
    background-color: white;
    border-radius: var(--radius-md);
    padding: 2rem;
    box-shadow: var(--shadow-md);
    flex: 1;
}

.testimonial-content {
    margin-bottom: 1.5rem;
}

.testimonial-content p {
    font-style: italic;
    position: relative;
}

.testimonial-content p:before,
.testimonial-content p:after {
    content: '"';
    font-size: 1.5rem;
    color: var(--primary-light);
}

.testimonial-author {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.testimonial-author img {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    object-fit: cover;
}

.author-info h4 {
    margin-bottom: 0.25rem;
}

.author-info span {
    color: var(--text-light);
    font-size: 0.9rem;
}

/* 页脚 */
.footer {
    background-color: #1e293b;
    color: white;
    padding: 5rem 0 2rem;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 3rem;
    margin-bottom: 3rem;
}

.footer-about p {
    margin-bottom: 1.5rem;
    opacity: 0.8;
}

/* 社交链接 */
.social-links {
    display: flex;
    gap: 1rem;
    margin-top: 1.5rem;
}

.social-links a {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background-color: rgba(255, 255, 255, 0.1);
    color: #fff;
    transition: all 0.3s ease;
}

.social-links a:hover {
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.social-links .social-icon svg {
    width: 20px;
    height: 20px;
}

.social-links .weixin {
    background-color: #2BAD13;
}

.social-links .weibo {
    background-color: #E6162D;
}

.social-links .qq {
    background-color: #12B7F5;
}

.social-links .weixin:hover {
    background-color: #3AC923;
}

.social-links .weibo:hover {
    background-color: #F72A40;
}

.social-links .qq:hover {
    background-color: #31C3F9;
}

.footer-links h3 {
    margin-bottom: 1.5rem;
    font-size: 1.2rem;
}

.footer-links ul li {
    margin-bottom: 0.75rem;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.7);
    transition: color 0.3s ease;
}

.footer-links a:hover {
    color: white;
}

.footer-contact p {
    margin-bottom: 0.75rem;
    opacity: 0.7;
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 2rem;
    text-align: center;
    opacity: 0.6;
}

/* 页面标题 */
.page-header {
    background-color: var(--bg-light);
    padding: 3rem 0;
    text-align: center;
}

.page-header h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.page-header p {
    font-size: 1.2rem;
    color: var(--text-light);
}

/* 响应式设计 */
@media (max-width: 1200px) {
    .container {
        max-width: 960px;
    }
}

@media (max-width: 992px) {
    .container {
        max-width: 720px;
    }
    
    .features-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .courses-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .hero .container,
    .lab-preview .container {
        grid-template-columns: 1fr;
    }
    
    .footer-grid {
        grid-template-columns: 1fr 1fr;
    }
}

@media (max-width: 768px) {
    .container {
        max-width: 540px;
    }
    
    .courses-grid,
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .testimonials-slider {
        flex-direction: column;
    }
    
    .header .container {
        flex-direction: column;
        padding: 1rem;
    }
    
    .nav ul {
        gap: 1rem;
        margin: 1rem 0;
    }
    
    .footer-grid {
        grid-template-columns: 1fr;
    }
}