:root {
    /* 主色调 - 深蓝紫渐变 */
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #8b5cf6;
    
    /* 辅助色调 */
    --secondary-color: #06b6d4;
    --accent-color: #f59e0b;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --error-color: #ef4444;
    
    /* 中性色调 */
    --gray-50: #f8fafc;
    --gray-100: #f1f5f9;
    --gray-200: #e2e8f0;
    --gray-300: #cbd5e1;
    --gray-400: #94a3b8;
    --gray-500: #64748b;
    --gray-600: #475569;
    --gray-700: #334155;
    --gray-800: #1e293b;
    --gray-900: #0f172a;
    
    /* 渐变色 */
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-secondary: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --gradient-success: linear-gradient(135deg, #4ade80 0%, #22c55e 100%);
    --gradient-warning: linear-gradient(135deg, #fbbf24 0%, #f59e0b 100%);
    --gradient-hero: linear-gradient(135deg, #667eea 0%, #764ba2 50%, #f093fb 100%);
    --gradient-card: linear-gradient(145deg, #ffffff 0%, #f8fafc 100%);
    --gradient-glass: linear-gradient(145deg, rgba(255, 255, 255, 0.1) 0%, rgba(255, 255, 255, 0.05) 100%);
    
    /* 阴影 */
    --shadow-xs: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --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);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    --shadow-inner: inset 0 2px 4px 0 rgba(0, 0, 0, 0.06);
    --shadow-glow: 0 0 20px rgba(99, 102, 241, 0.3);
    
    /* 圆角 */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-2xl: 1.5rem;
    --radius-3xl: 2rem;
    --radius-full: 9999px;
    
    /* 间距 */
    --spacing-xs: 0.5rem;
    --spacing-sm: 0.75rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
    --spacing-4xl: 5rem;
    
    /* 动画 */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-normal: 300ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 500ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-bounce: 400ms cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--gray-800);
    background: var(--gray-50);
    overflow-x: hidden;
    font-feature-settings: 'kern' 1, 'liga' 1;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* 全局背景 */
.main-background {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--gradient-hero);
    z-index: -2;
}

.main-background::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: 
        radial-gradient(circle at 20% 80%, rgba(120, 119, 198, 0.4) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(255, 119, 198, 0.3) 0%, transparent 50%),
        radial-gradient(circle at 40% 40%, rgba(120, 219, 255, 0.25) 0%, transparent 50%);
    animation: backgroundFloat 20s ease-in-out infinite;
}

.main-background::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: 
        radial-gradient(circle at 60% 30%, rgba(139, 92, 246, 0.2) 0%, transparent 40%),
        radial-gradient(circle at 30% 70%, rgba(59, 130, 246, 0.15) 0%, transparent 40%);
    animation: backgroundFloat 25s ease-in-out infinite reverse;
}

@keyframes backgroundFloat {
    0%, 100% { transform: scale(1) rotate(0deg); opacity: 1; }
    50% { transform: scale(1.1) rotate(180deg); opacity: 0.8; }
}

/* 容器 */
.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
    position: relative;
    z-index: 1;
}

/* 导航栏 */
.navbar {
    position: sticky;
    top: 0;
    z-index: 100;
    background: transparent;
    backdrop-filter: none;
    -webkit-backdrop-filter: none;
    border-bottom: none;
    padding: var(--spacing-md) 0;
    margin-bottom: var(--spacing-2xl);
    box-shadow: none;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.navbar.scrolled {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    border-bottom: none;
    box-shadow: 
        0 4px 20px rgba(0, 0, 0, 0.15),
        0 1px 0 rgba(255, 255, 255, 0.8) inset;
}

.navbar::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: transparent;
    border-radius: inherit;
    z-index: -1;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.navbar.scrolled::before {
    background: linear-gradient(135deg, 
        rgba(255, 255, 255, 0.8) 0%, 
        rgba(255, 255, 255, 0.6) 50%, 
        rgba(255, 255, 255, 0.7) 100%);
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 1.5rem;
    font-weight: 700;
    color: rgba(255, 255, 255, 0.95);
    text-decoration: none;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    text-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

.navbar.scrolled .logo {
    color: var(--gray-900);
    text-shadow: none;
}

.logo:hover {
    transform: translateY(-1px);
}

.navbar:not(.scrolled) .logo:hover {
    color: white;
}

.navbar.scrolled .logo:hover {
    color: var(--primary-color);
}

.logo-icon {
    width: 44px;
    height: 44px;
    background: var(--gradient-primary);
    border-radius: var(--radius-xl);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.2rem;
    box-shadow: 
        0 8px 16px rgba(99, 102, 241, 0.4),
        0 4px 8px rgba(0, 0, 0, 0.2),
        0 1px 0 rgba(255, 255, 255, 0.3) inset;
    transition: var(--transition-normal);
    position: relative;
    overflow: hidden;
}

.logo-icon::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
    transition: var(--transition-slow);
}

.logo:hover .logo-icon {
    box-shadow: 
        0 12px 24px rgba(99, 102, 241, 0.5),
        0 6px 12px rgba(0, 0, 0, 0.3),
        0 1px 0 rgba(255, 255, 255, 0.4) inset;
    transform: scale(1.05);
}

.logo:hover .logo-icon::before {
    left: 100%;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: var(--spacing-xl);
}

.nav-link {
    color: rgba(255, 255, 255, 0.85);
    text-decoration: none;
    font-weight: 500;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-md);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
}

.navbar.scrolled .nav-link {
    color: var(--gray-700);
    text-shadow: none;
}

.nav-link::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(255, 255, 255, 0.1);
    border-radius: inherit;
    opacity: 0;
    transition: var(--transition-fast);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
}

.navbar.scrolled .nav-link::before {
    background: rgba(0, 0, 0, 0.05);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    width: 0;
    height: 2px;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.8), transparent);
    transition: var(--transition-normal);
    transform: translateX(-50%);
    border-radius: 1px;
}

.navbar.scrolled .nav-link::after {
    background: linear-gradient(90deg, transparent, var(--primary-color), transparent);
}

.nav-link:hover {
    transform: translateY(-1px);
}

.navbar:not(.scrolled) .nav-link:hover {
    color: white;
}

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

.nav-link:hover::before {
    opacity: 1;
}

.nav-link:hover::after {
    width: 80%;
}

.follow-btn {
    background: rgba(255, 255, 255, 0.15);
    backdrop-filter: blur(16px) saturate(180%);
    -webkit-backdrop-filter: blur(16px) saturate(180%);
    color: white;
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-full);
    text-decoration: none;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 
        0 8px 32px rgba(0, 0, 0, 0.15),
        0 1px 0 rgba(255, 255, 255, 0.3) inset,
        0 -1px 0 rgba(0, 0, 0, 0.1) inset;
    position: relative;
    overflow: hidden;
    border: 1px solid rgba(255, 255, 255, 0.2);
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
}

.navbar.scrolled .follow-btn {
    background: var(--gradient-primary);
    color: white;
    border: 1px solid rgba(99, 102, 241, 0.3);
    text-shadow: none;
    box-shadow: 
        0 4px 16px rgba(99, 102, 241, 0.3),
        0 1px 0 rgba(255, 255, 255, 0.2) inset;
}

.follow-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: var(--transition-slow);
}

.follow-btn::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(255, 255, 255, 0.1);
    border-radius: inherit;
    opacity: 0;
    transition: var(--transition-fast);
}

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

.follow-btn:hover::after {
    opacity: 1;
}

.follow-btn:hover {
    transform: translateY(-2px);
}

.navbar:not(.scrolled) .follow-btn:hover {
    box-shadow: 
        0 12px 40px rgba(0, 0, 0, 0.2),
        0 1px 0 rgba(255, 255, 255, 0.4) inset,
        0 -1px 0 rgba(0, 0, 0, 0.1) inset;
    background: rgba(255, 255, 255, 0.2);
}

.navbar.scrolled .follow-btn:hover {
    box-shadow: 
        0 8px 24px rgba(99, 102, 241, 0.4),
        0 1px 0 rgba(255, 255, 255, 0.3) inset;
}

/* 英雄区域 */
.hero-section {
    text-align: center;
    padding: var(--spacing-3xl) 0;
    margin-bottom: var(--spacing-3xl);
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    background: var(--gradient-glass);
    backdrop-filter: blur(16px) saturate(180%);
    -webkit-backdrop-filter: blur(16px) saturate(180%);
    color: rgba(255, 255, 255, 0.9);
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-full);
    font-weight: 600;
    margin-bottom: var(--spacing-xl);
    border: 1px solid rgba(255, 255, 255, 0.2);
    box-shadow: 
        0 8px 32px rgba(0, 0, 0, 0.1),
        0 1px 0 rgba(255, 255, 255, 0.3) inset;
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
    transition: var(--transition-normal);
}

.hero-badge:hover {
    transform: translateY(-2px);
    box-shadow: 
        0 12px 40px rgba(0, 0, 0, 0.15),
        0 1px 0 rgba(255, 255, 255, 0.4) inset;
}

.hero-title {
    font-size: clamp(2.5rem, 5vw, 4rem);
    font-weight: 800;
    color: white;
    margin-bottom: var(--spacing-lg);
    line-height: 1.1;
    text-shadow: 
        0 4px 12px rgba(0, 0, 0, 0.3),
        0 2px 4px rgba(0, 0, 0, 0.2);
    letter-spacing: -0.02em;
}

.hero-title-gradient {
    background: linear-gradient(135deg, #fbbf24 0%, #f472b6 50%, #e879f9 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    color: #f472b6; /* 回退颜色，使用温暖的粉色 */
    display: inline-block;
    text-shadow: none; /* 渐变文字不需要阴影 */
}

.hero-subtitle {
    font-size: 1.125rem;
    color: rgba(255, 255, 255, 0.85);
    margin-bottom: var(--spacing-2xl);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
    line-height: 1.6;
    text-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

.hero-cta {
    display: flex;
    gap: var(--spacing-lg);
    justify-content: center;
    margin-bottom: var(--spacing-2xl);
    flex-wrap: wrap;
}

.btn-primary, .btn-secondary {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-md) var(--spacing-xl);
    border-radius: var(--radius-full);
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition-normal);
    position: relative;
    overflow: hidden;
    border: none;
    cursor: pointer;
    font-size: 1rem;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: 
        0 8px 24px rgba(99, 102, 241, 0.4),
        0 1px 0 rgba(255, 255, 255, 0.2) inset;
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.15);
    backdrop-filter: blur(16px) saturate(180%);
    -webkit-backdrop-filter: blur(16px) saturate(180%);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.2);
    box-shadow: 
        0 8px 32px rgba(0, 0, 0, 0.1),
        0 1px 0 rgba(255, 255, 255, 0.3) inset;
}

.btn-primary:hover, .btn-secondary:hover {
    transform: translateY(-2px);
}

.btn-primary:hover {
    box-shadow: 
        0 12px 32px rgba(99, 102, 241, 0.5),
        0 1px 0 rgba(255, 255, 255, 0.3) inset;
}

.btn-secondary:hover {
    box-shadow: 
        0 12px 40px rgba(0, 0, 0, 0.15),
        0 1px 0 rgba(255, 255, 255, 0.4) inset;
    background: rgba(255, 255, 255, 0.2);
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: var(--spacing-2xl);
    flex-wrap: wrap;
}

.stat-item {
    text-align: center;
    color: rgba(255, 255, 255, 0.9);
}

.stat-number {
    display: block;
    font-size: 2rem;
    font-weight: 800;
    color: white;
    text-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
    margin-bottom: var(--spacing-xs);
}

.stat-label {
    font-size: 0.875rem;
    color: rgba(255, 255, 255, 0.7);
    text-shadow: 0 1px 4px rgba(0, 0, 0, 0.3);
}

/* 加载覆盖层 */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--gradient-hero);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
    transition: var(--transition-slow);
}

.loading-overlay.hidden {
    opacity: 0;
    visibility: hidden;
}

.loading-spinner {
    width: 60px;
    height: 60px;
    border: 4px solid rgba(255, 255, 255, 0.2);
    border-top: 4px solid white;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    box-shadow: 0 0 20px rgba(255, 255, 255, 0.3);
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* 方法选择区域 */
.methods-section {
    padding: var(--spacing-4xl) 0;
    background: white;
    position: relative;
    margin: var(--spacing-2xl) 0 0 0;
    clip-path: polygon(0 5%, 20% 0%, 40% 3%, 60% 0%, 80% 4%, 100% 0%, 100% 100%, 0% 100%);
    box-shadow: 
        0 20px 40px rgba(0, 0, 0, 0.1),
        0 10px 20px rgba(0, 0, 0, 0.05);
}

.methods-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, 
        rgba(255, 255, 255, 1) 0%, 
        rgba(248, 250, 252, 0.95) 50%, 
        rgba(255, 255, 255, 1) 100%);
    z-index: -1;
}

.methods-section::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: 
        radial-gradient(circle at 20% 20%, rgba(99, 102, 241, 0.03) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(139, 92, 246, 0.03) 0%, transparent 50%);
    z-index: -1;
}

.section-header {
    text-align: center;
    margin-bottom: var(--spacing-3xl);
}

.section-title {
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--gray-900);
    margin-bottom: var(--spacing-lg);
    text-shadow: none;
}

.section-subtitle {
    font-size: 1rem;
    color: var(--gray-600);
    max-width: 600px;
    margin: 0 auto;
    line-height: 1.6;
}

.methods-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-3xl);
    align-items: start;
}

.method-card {
    background: var(--gradient-card);
    border-radius: var(--radius-xl);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-lg);
    transition: var(--transition-normal);
    cursor: pointer;
    position: relative;
    overflow: hidden;
    border: 1px solid rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(10px);
    height: 100%;
    display: flex;
    flex-direction: column;
}

.method-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: var(--spacing-md);
}

.method-icon {
    width: 48px;
    height: 48px;
    background: var(--gradient-primary);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.25rem;
    box-shadow: var(--shadow-md);
    transition: var(--transition-normal);
}

.difficulty-badge {
    padding: 4px 12px;
    border-radius: var(--radius-full);
    font-size: 0.7rem;
    font-weight: 600;
    color: white;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    box-shadow: var(--shadow-sm);
}

.method-title {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--gray-900);
    margin-bottom: var(--spacing-sm);
    line-height: 1.4;
}

.method-description {
    color: var(--gray-600);
    margin-bottom: var(--spacing-md);
    line-height: 1.5;
    font-size: 0.875rem;
    flex-grow: 1;
}

.method-tags {
    display: flex;
    gap: 6px;
    margin-bottom: var(--spacing-md);
    flex-wrap: wrap;
}

.method-tag {
    background: var(--gray-100);
    color: var(--gray-600);
    padding: 4px 8px;
    border-radius: var(--radius-sm);
    font-size: 0.7rem;
    font-weight: 500;
    transition: var(--transition-fast);
}

.method-features {
    list-style: none;
    margin-bottom: var(--spacing-md);
}

.method-features li {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    margin-bottom: 6px;
    color: var(--gray-600);
    font-size: 0.8rem;
}

.method-features i {
    color: var(--success-color);
    font-size: 0.875rem;
    width: 14px;
    flex-shrink: 0;
}

.method-button {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    background: var(--gradient-primary);
    color: white;
    padding: 10px var(--spacing-md);
    border-radius: var(--radius-full);
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition-normal);
    box-shadow: var(--shadow-md);
    width: 100%;
    justify-content: center;
    font-size: 0.8rem;
    margin-top: auto;
}

.method-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--gradient-primary);
    transform: scaleX(0);
    transition: var(--transition-normal);
}

.method-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-xl);
}

.method-card:hover::before {
    transform: scaleX(1);
}

.method-card:hover .method-icon {
    transform: scale(1.05);
    box-shadow: var(--shadow-lg);
}

.method-card:hover .method-tag {
    background: rgba(99, 102, 241, 0.1);
    color: var(--primary-color);
}

.method-button:hover {
    transform: translateY(-1px);
    box-shadow: var(--shadow-lg);
}

.difficulty-easy {
    background: var(--gradient-success);
}

.difficulty-medium {
    background: var(--gradient-warning);
}

.difficulty-hard {
    background: var(--gradient-secondary);
}

/* 页脚 */
.footer {
    background: transparent;
    color: rgba(255, 255, 255, 0.9);
    padding: var(--spacing-4xl) 0 var(--spacing-xl);
    text-align: center;
    position: relative;
    box-shadow: 
        0 -8px 32px rgba(0, 0, 0, 0.1),
        0 1px 0 rgba(255, 255, 255, 0.1) inset;
}

.footer::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, 
        rgba(255, 255, 255, 0.05) 0%, 
        rgba(255, 255, 255, 0.02) 50%, 
        rgba(255, 255, 255, 0.08) 100%);
    border-radius: inherit;
    z-index: -1;
}

.footer::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
}

.footer-content {
    max-width: 600px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
}

.footer-logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: white;
    margin-bottom: var(--spacing-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    text-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

.footer-logo i {
    background: var(--gradient-primary);
    padding: 8px;
    border-radius: var(--radius-lg);
    box-shadow: 
        0 4px 12px rgba(99, 102, 241, 0.4),
        0 1px 0 rgba(255, 255, 255, 0.3) inset;
}

.footer-text {
    color: rgba(255, 255, 255, 0.8);
    margin-bottom: var(--spacing-lg);
    line-height: 1.6;
    text-shadow: 0 1px 4px rgba(0, 0, 0, 0.3);
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
    flex-wrap: wrap;
}

.footer-link {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    transition: var(--transition-fast);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-md);
}

.footer-link:hover {
    color: white;
    background: rgba(255, 255, 255, 0.1);
    transform: translateY(-1px);
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: var(--spacing-lg);
    color: rgba(255, 255, 255, 0.6);
    font-size: 0.875rem;
}

/* 滚动动画 */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: var(--transition-slow);
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* QR弹窗 */
.follow-teacher {
    position: relative;
}

.qr-popup {
    position: absolute;
    top: calc(100% + 8px);
    right: 0;
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    padding: var(--spacing-md);
    border-radius: var(--radius-xl);
    box-shadow: 
        0 20px 40px rgba(0, 0, 0, 0.15),
        0 1px 0 rgba(255, 255, 255, 0.3) inset,
        0 -1px 0 rgba(0, 0, 0, 0.1) inset;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: var(--transition-normal);
    z-index: 1000;
    border: 1px solid rgba(255, 255, 255, 0.2);
    width: 280px;
    transform-origin: top right;
}

.qr-popup::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, 
        rgba(255, 255, 255, 0.2) 0%, 
        rgba(255, 255, 255, 0.05) 50%, 
        rgba(255, 255, 255, 0.15) 100%);
    border-radius: inherit;
    z-index: -1;
}

.follow-teacher:hover .qr-popup {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.qr-popup img {
    width: 250px;
    height: auto;
    max-height: 120px;
    border-radius: 0;
    margin-bottom: var(--spacing-sm);
    box-shadow: none;
    object-fit: contain;
    object-position: center;
    background: transparent;
    padding: 0;
    display: block;
}

.qr-title {
    font-weight: 600;
    text-align: center;
    color: white;
    margin-bottom: var(--spacing-xs);
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
}

.qr-subtitle {
    font-size: 0.875rem;
    color: rgba(255, 255, 255, 0.8);
    text-align: center;
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
}

/* 特殊效果 */
.sparkle {
    position: relative;
}

.sparkle::before {
    content: '✨';
    position: absolute;
    top: -10px;
    right: -10px;
    font-size: 1rem;
    animation: sparkle 2s ease-in-out infinite;
}

@keyframes sparkle {
    0%, 100% { opacity: 0; transform: scale(0.8) rotate(0deg); }
    50% { opacity: 1; transform: scale(1.2) rotate(180deg); }
}

/* 响应式设计 */
@media (max-width: 1200px) {
    .methods-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .hero-stats {
        gap: var(--spacing-lg);
    }
}

@media (max-width: 768px) {
    .methods-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }
    
    .hero-section {
        padding: var(--spacing-2xl) 0;
    }
    
    .hero-title {
        font-size: clamp(2rem, 8vw, 3rem);
        margin-bottom: var(--spacing-md);
    }
    
    .hero-subtitle {
        font-size: 1rem;
        margin-bottom: var(--spacing-xl);
    }
    
    .hero-cta {
        flex-direction: column;
        align-items: center;
        gap: var(--spacing-md);
    }
    
    .btn-primary, .btn-secondary {
        width: 100%;
        max-width: 280px;
        justify-content: center;
    }
    
    .hero-stats {
        gap: var(--spacing-lg);
        flex-direction: column;
    }
    
    .stat-item {
        min-width: 120px;
    }
    
    .nav-links {
        gap: var(--spacing-md);
    }
    
    .nav-link {
        padding: var(--spacing-xs) var(--spacing-sm);
        font-size: 0.875rem;
    }
    
    .follow-btn {
        padding: var(--spacing-xs) var(--spacing-md);
        font-size: 0.875rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .section-subtitle {
        font-size: 0.9rem;
    }
    
    .methods-section {
        padding: var(--spacing-3xl) 0;
    }
    
    .method-card {
        padding: var(--spacing-md);
    }
    
    .footer-links {
        flex-direction: column;
        gap: var(--spacing-sm);
    }
    
    .footer {
        padding: var(--spacing-3xl) 0 var(--spacing-lg);
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--spacing-md);
    }
    
    .navbar {
        padding: var(--spacing-sm) 0;
    }
    
    .logo {
        font-size: 1.25rem;
    }
    
    .logo-icon {
        width: 36px;
        height: 36px;
        font-size: 1rem;
    }
    
    .nav-links {
        gap: var(--spacing-sm);
    }
    
    .nav-link {
        padding: 6px 8px;
        font-size: 0.8rem;
    }
    
    .follow-btn {
        padding: 6px var(--spacing-sm);
        font-size: 0.8rem;
        gap: 4px;
    }
    
    .hero-section {
        padding: var(--spacing-xl) 0;
    }
    
    .hero-title {
        font-size: 1.75rem;
        line-height: 1.2;
    }
    
    .hero-subtitle {
        font-size: 0.9rem;
        margin-bottom: var(--spacing-lg);
    }
    
    .hero-badge {
        font-size: 0.8rem;
        padding: 6px var(--spacing-md);
        margin-bottom: var(--spacing-md);
    }
    
    .btn-primary, .btn-secondary {
        padding: var(--spacing-sm) var(--spacing-lg);
        font-size: 0.9rem;
    }
    
    .hero-stats {
        gap: var(--spacing-md);
    }
    
    .stat-number {
        font-size: 1.5rem;
    }
    
    .stat-label {
        font-size: 0.8rem;
    }
    
    .section-title {
        font-size: 1.75rem;
    }
    
    .section-subtitle {
        font-size: 0.85rem;
    }
    
    .methods-section {
        padding: var(--spacing-2xl) 0;
        margin: var(--spacing-xl) 0 0 0;
    }
    
    .method-card {
        padding: var(--spacing-sm);
    }
    
    .method-title {
        font-size: 1rem;
    }
    
    .method-description {
        font-size: 0.8rem;
    }
    
    .method-button {
        padding: 8px var(--spacing-sm);
        font-size: 0.75rem;
    }
    
    .footer {
        padding: var(--spacing-2xl) 0 var(--spacing-md);
    }
    
    .footer-logo {
        font-size: 1.25rem;
    }
    
    .footer-text {
        font-size: 0.875rem;
    }
    
    .qr-popup {
        width: 240px;
        right: -20px;
    }
    
    .qr-popup img {
        width: 200px;
    }
}

@media (max-width: 360px) {
    .container {
        padding: 0 var(--spacing-sm);
    }
    
    .hero-title {
        font-size: 1.5rem;
    }
    
    .section-title {
        font-size: 1.5rem;
    }
    
    .nav-links {
        display: none;
    }
    
    .follow-btn {
        font-size: 0.75rem;
        padding: 4px 8px;
    }
    
    .methods-grid {
        gap: var(--spacing-sm);
    }
    
    .qr-popup {
        width: 200px;
        right: -10px;
    }
    
    .qr-popup img {
        width: 160px;
    }
}