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

:root {
    --primary-color: #2563eb;
    --secondary-color: #1e40af;
    --accent-color: #f59e0b;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --text-light: #9ca3af;
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-dark: #1f2937;
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-secondary: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --gradient-accent: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    overflow-x: hidden;
}

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

/* 按钮样式 */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 500;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.btn::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: left 0.5s;
}

.btn:hover::before {
    left: 100%;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: var(--shadow-md);
}

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

.btn-secondary {
    background: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
}

.btn-secondary:hover {
    background: var(--primary-color);
    color: white;
    transform: translateY(-2px);
}

.btn-outline {
    background: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
    padding: 10px 20px;
    font-size: 14px;
}

.btn-outline:hover {
    background: var(--primary-color);
    color: white;
}

/* 导航栏 */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: all 0.3s ease;
}

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

.nav-logo {
    display: flex;
    align-items: center;
    font-size: 24px;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;
}

.nav-logo i {
    margin-right: 10px;
    font-size: 28px;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 30px;
}

.nav-link {
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient-primary);
    transition: width 0.3s ease;
}

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

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.bar {
    width: 25px;
    height: 3px;
    background: var(--text-primary);
    margin: 3px 0;
    transition: 0.3s;
}

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

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1000 1000"><polygon fill="rgba(255,255,255,0.1)" points="0,1000 1000,0 1000,1000"/></svg>');
    background-size: cover;
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
    position: relative;
    z-index: 2;
}

.hero-content {
    color: white;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 20px;
    line-height: 1.2;
    animation: fadeInUp 1s ease;
}

.hero-subtitle {
    font-size: 1.25rem;
    margin-bottom: 30px;
    opacity: 0.9;
    animation: fadeInUp 1s ease 0.2s both;
}

.hero-buttons {
    display: flex;
    gap: 20px;
    animation: fadeInUp 1s ease 0.4s both;
}

.hero-image {
    display: flex;
    justify-content: center;
    align-items: center;
}

.hero-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    padding: 40px;
    border-radius: 20px;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.stat-item {
    text-align: center;
    color: white;
}

.stat-item h3 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 10px;
    background: var(--gradient-accent);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-item p {
    font-size: 1rem;
    opacity: 0.9;
}

/* 章节标题 */
.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-header h2 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 15px;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.section-header p {
    font-size: 1.125rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

/* 关于我们 */
.about {
    padding: 100px 0;
    background: var(--bg-secondary);
}

.about-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.about-text h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.about-text p {
    color: var(--text-secondary);
    margin-bottom: 30px;
    line-height: 1.7;
}

.features {
    display: grid;
    gap: 25px;
    margin-top: 30px;
}

.feature {
    display: flex;
    align-items: flex-start;
    gap: 15px;
    padding: 20px;
    background: white;
    border-radius: 12px;
    box-shadow: var(--shadow-sm);
    transition: all 0.3s ease;
}

.feature:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.feature i {
    font-size: 24px;
    color: var(--primary-color);
    margin-top: 5px;
}

.feature h4 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-primary);
}

.feature p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    margin: 0;
}

.about-image img {
    width: 100%;
    height: 400px;
    object-fit: cover;
    border-radius: 20px;
    box-shadow: var(--shadow-xl);
}

/* 课程体系 */
.courses {
    padding: 100px 0;
}

.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.course-card {
    background: white;
    border-radius: 20px;
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease;
    position: relative;
}

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

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

.course-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.3s ease;
}

.course-card:hover .course-image img {
    transform: scale(1.1);
}

.course-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(37, 99, 235, 0.8);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.course-card:hover .course-overlay {
    opacity: 1;
}

.course-overlay i {
    font-size: 48px;
    color: white;
}

.course-content {
    padding: 30px;
}

.course-content h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.course-content p {
    color: var(--text-secondary);
    margin-bottom: 20px;
    line-height: 1.6;
}

.course-content ul {
    list-style: none;
    margin-bottom: 25px;
}

.course-content li {
    padding: 8px 0;
    color: var(--text-secondary);
    position: relative;
    padding-left: 20px;
}

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

/* 师资团队 */
.teachers {
    padding: 100px 0;
    background: var(--bg-secondary);
}

.teachers-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 40px;
}

.teacher-card {
    background: white;
    border-radius: 20px;
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease;
    text-align: center;
}

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

.teacher-image {
    height: 250px;
    overflow: hidden;
}

.teacher-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.3s ease;
}

.teacher-card:hover .teacher-image img {
    transform: scale(1.1);
}

.teacher-info {
    padding: 30px;
}

.teacher-info h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.teacher-title {
    color: var(--primary-color);
    font-weight: 500;
    margin-bottom: 15px;
}

.teacher-desc {
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 20px;
}

.teacher-social {
    display: flex;
    justify-content: center;
    gap: 15px;
}

.teacher-social a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: var(--bg-secondary);
    border-radius: 50%;
    color: var(--text-secondary);
    text-decoration: none;
    transition: all 0.3s ease;
}

.teacher-social a:hover {
    background: var(--primary-color);
    color: white;
    transform: translateY(-3px);
}

/* 联系我们 */
.contact {
    padding: 100px 0;
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
}

.contact-info {
    display: grid;
    gap: 30px;
}

.contact-item {
    display: flex;
    align-items: flex-start;
    gap: 20px;
    padding: 25px;
    background: var(--bg-secondary);
    border-radius: 15px;
    transition: all 0.3s ease;
}

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

.contact-item i {
    font-size: 24px;
    color: var(--primary-color);
    margin-top: 5px;
}

.contact-item h4 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-primary);
}

.contact-item p {
    color: var(--text-secondary);
    margin: 0;
}

.contact-form {
    background: white;
    padding: 40px;
    border-radius: 20px;
    box-shadow: var(--shadow-lg);
}

.form-group {
    margin-bottom: 20px;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 15px;
    border: 2px solid var(--border-color);
    border-radius: 10px;
    font-size: 16px;
    transition: all 0.3s ease;
    background: var(--bg-secondary);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    background: white;
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

/* 页脚 */
.footer {
    background: var(--bg-dark);
    color: white;
    padding: 60px 0 20px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-bottom: 40px;
}

.footer-logo {
    display: flex;
    align-items: center;
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 20px;
}

.footer-logo i {
    margin-right: 10px;
    color: var(--accent-color);
}

.footer-section p {
    color: #9ca3af;
    line-height: 1.6;
    margin-bottom: 20px;
}

.footer-section h4 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 20px;
    color: white;
}

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

.footer-section ul li {
    margin-bottom: 10px;
}

.footer-section ul li a {
    color: #9ca3af;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-section ul li a:hover {
    color: var(--accent-color);
}

.social-links {
    display: flex;
    gap: 15px;
}

.social-links a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    color: white;
    text-decoration: none;
    transition: all 0.3s ease;
}

.social-links a:hover {
    background: var(--accent-color);
    transform: translateY(-3px);
}

.newsletter {
    display: flex;
    gap: 10px;
}

.newsletter input {
    flex: 1;
    padding: 12px;
    border: none;
    border-radius: 8px;
    background: rgba(255, 255, 255, 0.1);
    color: white;
}

.newsletter input::placeholder {
    color: #9ca3af;
}

.newsletter .btn {
    padding: 12px 20px;
    font-size: 14px;
}

.footer-bottom {
    text-align: center;
    padding-top: 20px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: #9ca3af;
}

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

@keyframes slideInLeft {
    from {
        opacity: 0;
        transform: translateX(-30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes slideInRight {
    from {
        opacity: 0;
        transform: translateX(30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

/* 响应式设计 */
@media (max-width: 768px) {
    .hamburger {
        display: flex;
    }

    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: white;
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: var(--shadow-lg);
        padding: 20px 0;
    }

    .nav-menu.active {
        left: 0;
    }

    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 40px;
    }

    .hero-title {
        font-size: 2.5rem;
    }

    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }

    .about-content {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .contact-content {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .hero-stats {
        grid-template-columns: 1fr;
        gap: 20px;
    }

    .courses-grid {
        grid-template-columns: 1fr;
    }

    .teachers-grid {
        grid-template-columns: 1fr;
    }

    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .newsletter {
        flex-direction: column;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }

    .hero-title {
        font-size: 2rem;
    }

    .section-header h2 {
        font-size: 2rem;
    }

    .course-content,
    .teacher-info,
    .contact-form {
        padding: 20px;
    }
}

/* 滚动条样式 */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: var(--primary-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--secondary-color);
}

/* 平滑滚动 */
html {
    scroll-behavior: smooth;
}

/* 选择文本样式 */
::selection {
    background: var(--primary-color);
    color: white;
}

/* 焦点样式 */
*:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* 加载动画 */
.loading {
    opacity: 0;
    transform: translateY(20px);
    transition: all 0.6s ease;
}

.loading.loaded {
    opacity: 1;
    transform: translateY(0);
}