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

/* 根变量定义 */
:root {
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --secondary-color: #ec4899;
    --accent-color: #f59e0b;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --text-light: #9ca3af;
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
    --border-radius: 12px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* 基础样式 */
body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 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 24px;
}

/* 导航栏 */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: var(--transition);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 80px;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--primary-color);
    font-size: 2rem;
    transition: var(--transition);
}

.logo-icon:hover {
    transform: scale(1.1);
    color: var(--primary-dark);
}

.nav-logo h1 {
    font-size: 28px;
    font-weight: 700;
    background: var(--bg-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.logo-subtitle {
    font-size: 12px;
    color: var(--text-secondary);
    font-weight: 500;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 32px;
}

/* 语言选择器 */
.language-selector {
    position: relative;
}

.language-btn {
    background: transparent;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 8px 16px;
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    transition: var(--transition);
    color: var(--text-secondary);
    font-size: 0.9rem;
}

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

.language-btn i.fa-chevron-down {
    font-size: 0.7rem;
    transition: var(--transition);
}

.language-btn.active i.fa-chevron-down {
    transform: rotate(180deg);
}

.language-dropdown {
    position: absolute;
    top: 100%;
    right: 0;
    background: white;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-lg);
    min-width: 160px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: var(--transition);
    z-index: 1000;
    max-height: 400px;
    overflow-y: auto;
}

.language-dropdown.show {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.language-option {
    padding: 12px 16px;
    cursor: pointer;
    transition: var(--transition);
    color: var(--text-secondary);
    font-size: 0.9rem;
    border-bottom: 1px solid var(--border-color);
    display: block;
    width: 100%;
}

.language-dropdown .language-option:last-child {
    border-bottom: none !important;
}

.language-option:nth-last-child(1) {
    border-bottom: none !important;
}

/* 直接针对阿拉伯语选项 */
.language-option[data-lang="ar"] {
    border-bottom: none !important;
}

.language-option:hover {
    background: var(--bg-secondary);
    color: var(--primary-color);
}

.language-option.active {
    background: var(--primary-color);
    color: white;
}

.language-option.active:hover {
    background: var(--primary-dark);
}

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

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transition: var(--transition);
}

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

.cta-button {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: var(--border-radius);
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: var(--shadow-md);
}

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

/* 主页面内容 */
main {
    margin-top: 80px;
}

/* 英雄区块 */
.hero {
    min-height: 90vh;
    display: flex;
    align-items: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    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 0 100 100"><defs><pattern id="grid" width="10" height="10" patternUnits="userSpaceOnUse"><path d="M 10 0 L 0 0 0 10" fill="none" stroke="rgba(255,255,255,0.1)" stroke-width="0.5"/></pattern></defs><rect width="100" height="100" fill="url(%23grid)"/></svg>');
    opacity: 0.3;
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
    position: relative;
    z-index: 1;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 24px;
}

.highlight {
    background: linear-gradient(45deg, #fbbf24, #f59e0b);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-description {
    font-size: 1.25rem;
    line-height: 1.6;
    opacity: 0.9;
    margin-bottom: 40px;
}

.hero-buttons {
    display: flex;
    gap: 20px;
}

.primary-button, .secondary-button {
    padding: 16px 32px;
    border-radius: var(--border-radius);
    font-weight: 600;
    font-size: 1.1rem;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 8px;
    border: none;
}

.primary-button {
    background: rgba(255, 255, 255, 0.15);
    color: white;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.primary-button:hover {
    background: rgba(255, 255, 255, 0.25);
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl);
}

.secondary-button {
    background: transparent;
    color: white;
    border: 2px solid rgba(255, 255, 255, 0.3);
}

.secondary-button:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: rgba(255, 255, 255, 0.5);
}

/* 浮动卡片 */
.hero-visual {
    position: relative;
    height: 400px;
}

.floating-cards {
    position: relative;
    height: 100%;
}

.card {
    position: absolute;
    background: rgba(255, 255, 255, 0.15);
    backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: var(--border-radius);
    padding: 24px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
    color: white;
    box-shadow: var(--shadow-lg);
    transition: var(--transition);
    animation: float 6s ease-in-out infinite;
}

.card i {
    font-size: 2rem;
    opacity: 0.9;
}

.card span {
    font-weight: 600;
    font-size: 0.9rem;
}

.card-1 {
    top: 20%;
    left: 10%;
    animation-delay: 0s;
}

.card-2 {
    top: 50%;
    right: 20%;
    animation-delay: -2s;
}

.card-3 {
    bottom: 20%;
    left: 30%;
    animation-delay: -4s;
}

@keyframes float {
    0%, 100% { transform: translateY(0px) rotate(0deg); }
    25% { transform: translateY(-20px) rotate(1deg); }
    50% { transform: translateY(-10px) rotate(-1deg); }
    75% { transform: translateY(-15px) rotate(0.5deg); }
}

.card:hover {
    transform: translateY(-10px) scale(1.05);
    background: rgba(255, 255, 255, 0.25);
}

/* 功能特色区块 */
.features {
    padding: 120px 0;
    background: var(--bg-secondary);
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 60px;
    color: var(--text-primary);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 40px;
}

.feature-card {
    background: white;
    padding: 40px 32px;
    border-radius: var(--border-radius);
    text-align: center;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    border: 1px solid var(--border-color);
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
}

.feature-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    font-size: 2rem;
}

.feature-card h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.feature-card p {
    color: var(--text-secondary);
    line-height: 1.6;
}

/* 学科覆盖区块 */
.subjects {
    padding: 120px 0;
    background: white;
}

.subjects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: 32px;
    max-width: 800px;
    margin: 0 auto;
}

.subject-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 16px;
    padding: 32px 20px;
    background: var(--bg-secondary);
    border-radius: var(--border-radius);
    transition: var(--transition);
    cursor: pointer;
}

.subject-item:hover {
    transform: translateY(-4px);
    background: var(--primary-color);
    color: white;
}

.subject-item i {
    font-size: 2.5rem;
    color: var(--primary-color);
    transition: var(--transition);
}

.subject-item:hover i {
    color: white;
}

.subject-item span {
    font-weight: 600;
    font-size: 1rem;
}

/* 关于我们区块 */
.about {
    padding: 120px 0;
    background: var(--bg-secondary);
}

.about-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 80px;
    align-items: center;
}

.about-text h2 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 32px;
    color: var(--text-primary);
}

.about-text p {
    font-size: 1.125rem;
    line-height: 1.7;
    color: var(--text-secondary);
    margin-bottom: 48px;
}

.stats {
    display: flex;
    gap: 48px;
}

.stat {
    text-align: center;
}

.stat-number {
    display: block;
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 8px;
}

.stat-label {
    font-size: 0.9rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.about-visual {
    display: flex;
    justify-content: center;
    align-items: center;
}

.about-image {
    width: 200px;
    height: 200px;
    border-radius: 50%;
    background: var(--bg-gradient);
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-xl);
}

.about-image i {
    font-size: 4rem;
    color: white;
}

/* 行动召唤区块 */
.cta {
    padding: 120px 0;
    background: var(--bg-gradient);
    color: white;
    text-align: center;
}

.cta-content h2 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 24px;
}

.cta-content p {
    font-size: 1.25rem;
    opacity: 0.9;
    margin-bottom: 40px;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.cta-button-large {
    background: rgba(255, 255, 255, 0.15);
    color: white;
    border: 2px solid rgba(255, 255, 255, 0.3);
    padding: 20px 40px;
    border-radius: var(--border-radius);
    font-size: 1.25rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    gap: 12px;
    backdrop-filter: blur(10px);
}

.cta-button-large:hover {
    background: rgba(255, 255, 255, 0.25);
    border-color: rgba(255, 255, 255, 0.5);
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl);
}

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

.footer-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 60px;
    margin-bottom: 40px;
}

.footer-brand h3 {
    font-size: 1.5rem;
    margin-bottom: 16px;
    background: var(--bg-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.footer-brand p {
    opacity: 0.8;
    line-height: 1.6;
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px;
}

.footer-column h4 {
    font-size: 1.1rem;
    margin-bottom: 20px;
    color: white;
}

.footer-column a {
    display: block;
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    margin-bottom: 12px;
    transition: var(--transition);
}

.footer-column a:hover {
    color: white;
    padding-left: 4px;
}

.social-links {
    display: flex;
    gap: 16px;
}

.social-links a {
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
    margin-bottom: 0;
}

.social-links a:hover {
    background: var(--primary-color);
    transform: translateY(-2px);
    padding-left: 0;
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 20px;
    text-align: center;
    opacity: 0.7;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .nav-menu {
        display: flex;
        align-items: center;
        justify-content: flex-end;
        gap: 10px;
    }
    
    /* 隐藏导航链接和CTA按钮，只保留语言切换器 */
    .nav-menu .nav-link,
    .nav-menu .cta-button {
        display: none;
    }
    
    /* 移动端显示语言切换器 */
    .nav-menu.mobile-menu {
        display: flex;
        flex-direction: column;
        position: fixed;
        top: 80px;
        left: 0;
        right: 0;
        background: white;
        border-top: 1px solid var(--border-color);
        padding: 20px;
        gap: 20px;
        box-shadow: var(--shadow-lg);
    }
    
    /* 移动端语言按钮优化 */
    .language-btn {
        font-size: 0.8rem;
        padding: 6px 12px;
        min-width: 80px;
    }
    
    .language-dropdown {
        position: static;
        opacity: 1;
        visibility: visible;
        transform: none;
        box-shadow: none;
        border: 1px solid var(--border-color);
        margin-top: 10px;
        min-width: 120px;
    }
    
    .language-option {
        font-size: 0.8rem;
        padding: 10px 12px;
    }
    
    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 40px;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-buttons {
        justify-content: center;
        flex-wrap: wrap;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .subjects-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 20px;
    }
    
    .about-content {
        grid-template-columns: 1fr;
        gap: 40px;
        text-align: center;
    }
    
    .stats {
        justify-content: center;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        gap: 40px;
    }
    
    .footer-links {
        grid-template-columns: 1fr;
        gap: 30px;
    }
    
    .container {
        padding: 0 16px;
    }
    
    .section-title {
        font-size: 2rem;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-description {
        font-size: 1rem;
    }
    
    .subjects-grid {
        grid-template-columns: 1fr;
    }
    
    .stats {
        flex-direction: column;
        gap: 24px;
    }
}