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

/* 根变量 - 高级蓝色主题 */
:root {
    /* 主色调 - 深邃海洋蓝 */
    --primary-color: #0066cc;
    --primary-dark: #004d99;
    --primary-light: #3385d6;
    --primary-lighter: #e6f2ff;
    --accent-color: #00a8e8;
    --accent-gradient: linear-gradient(135deg, #0066cc 0%, #00a8e8 100%);

    /* 中性色 */
    --text-primary: #1a1a2e;
    --text-secondary: #4a5568;
    --text-tertiary: #718096;
    --text-light: #a0aec0;

    /* 背景色 */
    --bg-white: #ffffff;
    --bg-light: #f7fafc;
    --bg-gray: #edf2f7;
    --bg-card: #ffffff;

    /* 边框 */
    --border-color: #e2e8f0;
    --border-light: #f0f4f8;

    /* 阴影系统 */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.05), 0 1px 2px rgba(0, 0, 0, 0.03);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.05), 0 2px 4px rgba(0, 0, 0, 0.03);
    --shadow-lg: 0 10px 25px rgba(0, 102, 204, 0.08), 0 4px 10px rgba(0, 0, 0, 0.03);
    --shadow-xl: 0 20px 40px rgba(0, 102, 204, 0.12), 0 8px 16px rgba(0, 0, 0, 0.04);
    --shadow-hover: 0 15px 35px rgba(0, 102, 204, 0.15), 0 6px 12px rgba(0, 0, 0, 0.05);

    /* 过渡效果 */
    --transition-base: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: all 0.5s cubic-bezier(0.4, 0, 0.2, 1);

    /* 间距系统 */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
    --spacing-3xl: 6rem;

    /* 圆角系统 */
    --radius-sm: 6px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --radius-full: 9999px;
}

/* 基础样式 */
html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Segoe UI", "Roboto", "Helvetica Neue", Arial, sans-serif;
    line-height: 1.7;
    color: var(--text-primary);
    background: linear-gradient(180deg, var(--bg-white) 0%, var(--bg-light) 100%);
    min-height: 100vh;
}

/* 容器 */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

/* 头部导航 - 玻璃拟态效果 */
header {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    border-bottom: 1px solid var(--border-light);
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: var(--shadow-sm);
    transition: var(--transition-base);
}

header:hover {
    box-shadow: var(--shadow-md);
}

header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: var(--spacing-md);
    padding-bottom: var(--spacing-md);
}

.logo {
    font-size: 1.75rem;
    font-weight: 700;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.02em;
    transition: var(--transition-base);
}

.logo a {
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-decoration: none;
    transition: var(--transition-base);
}

.logo a:hover {
    opacity: 0.8;
    transform: translateY(-1px);
}

/* 语言切换按钮 - 精致圆角 */
.lang-toggle {
    padding: var(--spacing-xs) var(--spacing-md);
    background: var(--bg-white);
    border: 1.5px solid var(--border-color);
    border-radius: var(--radius-full);
    color: var(--text-secondary);
    font-size: 0.875rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-base);
    box-shadow: var(--shadow-sm);
}

.lang-toggle:hover {
    background: var(--primary-color);
    color: var(--bg-white);
    border-color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.lang-toggle:active {
    transform: translateY(0);
}

/* 主内容区域 */
main {
    min-height: calc(100vh - 200px);
}

/* Hero 区域 - 现代渐变设计 */
.hero {
    background: var(--accent-gradient);
    position: relative;
    overflow: hidden;
    color: var(--bg-white);
    padding: var(--spacing-3xl) 0;
    text-align: center;
}

/* Hero 背景装饰 */
.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -10%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(255, 255, 255, 0.1) 0%, transparent 70%);
    border-radius: 50%;
    pointer-events: none;
}

.hero::after {
    content: '';
    position: absolute;
    bottom: -30%;
    left: -5%;
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, rgba(0, 168, 232, 0.3) 0%, transparent 70%);
    border-radius: 50%;
    pointer-events: none;
}

.hero .container {
    position: relative;
    z-index: 1;
}

.hero h2 {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: var(--spacing-md);
    line-height: 1.2;
    letter-spacing: -0.03em;
    text-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
}

.hero p {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-xl);
    opacity: 0.95;
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
    font-weight: 400;
    line-height: 1.6;
}

/* 按钮样式 - 高级质感 */
.cta-buttons {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
}

.btn-primary,
.btn-secondary {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 14px 32px;
    border-radius: var(--radius-full);
    font-size: 1rem;
    font-weight: 600;
    text-decoration: none;
    transition: var(--transition-base);
    cursor: pointer;
    border: 2px solid transparent;
    letter-spacing: -0.01em;
    position: relative;
    overflow: hidden;
}

.btn-primary {
    background: var(--bg-white);
    color: var(--primary-color);
    box-shadow: 0 4px 14px rgba(0, 0, 0, 0.1);
}

.btn-primary:hover {
    background: var(--bg-light);
    transform: translateY(-3px);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.15);
    backdrop-filter: blur(10px);
    color: var(--bg-white);
    border-color: rgba(255, 255, 255, 0.4);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.25);
    border-color: rgba(255, 255, 255, 0.6);
    transform: translateY(-3px);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
}

.btn-primary:active,
.btn-secondary:active {
    transform: translateY(-1px);
}

/* 功能区域 - 现代卡片设计 */
.features {
    padding: var(--spacing-3xl) 0;
    background: var(--bg-light);
}

.features h3 {
    font-size: 2.5rem;
    font-weight: 800;
    text-align: center;
    margin-bottom: var(--spacing-3xl);
    color: var(--text-primary);
    letter-spacing: -0.03em;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--spacing-xl);
}

.feature-card {
    background: var(--bg-card);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-light);
    transition: var(--transition-base);
    position: relative;
    overflow: hidden;
}

/* 卡片悬浮效果 */
.feature-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--accent-gradient);
    transform: scaleX(0);
    transform-origin: left;
    transition: var(--transition-base);
}

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

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

.feature-icon {
    font-size: 3.5rem;
    margin-bottom: var(--spacing-md);
    display: inline-block;
    transition: var(--transition-base);
}

.feature-card:hover .feature-icon {
    transform: scale(1.1) rotate(5deg);
}

.feature-card h4 {
    font-size: 1.375rem;
    margin-bottom: var(--spacing-sm);
    color: var(--primary-color);
    font-weight: 700;
    letter-spacing: -0.02em;
}

.feature-card p {
    color: var(--text-secondary);
    line-height: 1.7;
    font-size: 0.9375rem;
}

/* 隐私安全区域 */
.privacy-section {
    padding: var(--spacing-3xl) 0;
    background: var(--bg-white);
    text-align: center;
    position: relative;
}

.privacy-section h3 {
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
    letter-spacing: -0.03em;
}

.privacy-section p {
    font-size: 1.125rem;
    color: var(--text-secondary);
    max-width: 800px;
    margin: 0 auto var(--spacing-xl);
    line-height: 1.7;
}

.policy-links {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
}

.policy-link {
    display: inline-flex;
    align-items: center;
    padding: 14px 32px;
    background: var(--primary-color);
    color: var(--bg-white);
    text-decoration: none;
    border-radius: var(--radius-full);
    font-weight: 600;
    transition: var(--transition-base);
    box-shadow: var(--shadow-md);
    letter-spacing: -0.01em;
}

.policy-link:hover {
    background: var(--primary-dark);
    transform: translateY(-3px);
    box-shadow: var(--shadow-hover);
}

.policy-link:active {
    transform: translateY(-1px);
}

/* 联系区域 */
.contact {
    padding: var(--spacing-3xl) 0;
    background: linear-gradient(180deg, var(--bg-light) 0%, var(--bg-white) 100%);
    text-align: center;
}

.contact h3 {
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
    letter-spacing: -0.03em;
}

.contact p {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    line-height: 1.7;
}

.email-link {
    display: inline-block;
    font-size: 1.375rem;
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 700;
    transition: var(--transition-base);
    position: relative;
    padding-bottom: 4px;
}

.email-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--accent-gradient);
    transform: scaleX(0);
    transform-origin: right;
    transition: var(--transition-base);
}

.email-link:hover::after {
    transform: scaleX(1);
    transform-origin: left;
}

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

/* 政策页面样式 - 优雅排版 */
.policy-page {
    padding: var(--spacing-3xl) 0;
    background: linear-gradient(180deg, var(--bg-light) 0%, var(--bg-white) 100%);
}

.policy-content {
    background: var(--bg-card);
    padding: var(--spacing-3xl);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-lg);
    max-width: 900px;
    margin: 0 auto;
    border: 1px solid var(--border-light);
}

.policy-content h2 {
    font-size: 2.75rem;
    font-weight: 800;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: var(--spacing-sm);
    padding-bottom: var(--spacing-md);
    border-bottom: 3px solid transparent;
    border-image: var(--accent-gradient) 1;
    letter-spacing: -0.03em;
}

.last-updated {
    color: var(--text-light);
    font-size: 0.875rem;
    margin-bottom: var(--spacing-xl);
    font-style: italic;
}

.policy-content section {
    margin-bottom: var(--spacing-xl);
}

.policy-content h3 {
    font-size: 1.875rem;
    color: var(--primary-color);
    margin-bottom: var(--spacing-md);
    margin-top: var(--spacing-xl);
    font-weight: 700;
    letter-spacing: -0.02em;
}

.policy-content h4 {
    font-size: 1.25rem;
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
    margin-top: var(--spacing-lg);
    font-weight: 600;
    letter-spacing: -0.01em;
}

.policy-content p {
    margin-bottom: var(--spacing-md);
    line-height: 1.8;
    color: var(--text-secondary);
}

.policy-content ul {
    margin-left: var(--spacing-xl);
    margin-bottom: var(--spacing-md);
}

.policy-content li {
    margin-bottom: var(--spacing-sm);
    line-height: 1.8;
    color: var(--text-secondary);
    padding-left: var(--spacing-xs);
}

.policy-content li::marker {
    color: var(--primary-color);
}

.policy-content strong {
    color: var(--text-primary);
    font-weight: 600;
}

.policy-content a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition-base);
    position: relative;
}

.policy-content a::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    right: 0;
    height: 1px;
    background: var(--primary-color);
    transform: scaleX(0);
    transform-origin: right;
    transition: var(--transition-base);
}

.policy-content a:hover::after {
    transform: scaleX(1);
    transform-origin: left;
}

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

/* 页脚 - 现代简约 */
footer {
    background: linear-gradient(135deg, var(--text-primary) 0%, #16213e 100%);
    color: var(--bg-white);
    padding: var(--spacing-xl) 0;
    text-align: center;
    position: relative;
    overflow: hidden;
}

footer::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
}

footer p {
    margin: 0;
    font-size: 0.9375rem;
    opacity: 0.9;
    font-weight: 500;
}

/* 响应式设计 - 平板 */
@media (max-width: 768px) {
    :root {
        --spacing-3xl: 4rem;
    }

    html {
        font-size: 15px;
    }

    header .container {
        padding-top: var(--spacing-sm);
        padding-bottom: var(--spacing-sm);
    }

    .logo {
        font-size: 1.5rem;
    }

    .hero {
        padding: var(--spacing-2xl) 0;
    }

    .hero h2 {
        font-size: 2.25rem;
    }

    .hero p {
        font-size: 1.125rem;
    }

    .features,
    .privacy-section,
    .contact {
        padding: var(--spacing-2xl) 0;
    }

    .features h3,
    .privacy-section h3,
    .contact h3 {
        font-size: 2rem;
    }

    .feature-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }

    .policy-content {
        padding: var(--spacing-xl);
    }

    .policy-content h2 {
        font-size: 2.25rem;
    }

    .policy-content h3 {
        font-size: 1.625rem;
    }

    .policy-content h4 {
        font-size: 1.125rem;
    }
}

/* 响应式设计 - 手机 */
@media (max-width: 480px) {
    :root {
        --spacing-3xl: 3rem;
    }

    .container {
        padding: 0 var(--spacing-md);
    }

    .hero {
        padding: var(--spacing-xl) 0;
    }

    .hero h2 {
        font-size: 2rem;
    }

    .hero p {
        font-size: 1rem;
    }

    .cta-buttons {
        flex-direction: column;
        gap: var(--spacing-sm);
    }

    .btn-primary,
    .btn-secondary {
        width: 100%;
        max-width: 320px;
    }

    .features,
    .privacy-section,
    .contact {
        padding: var(--spacing-xl) 0;
    }

    .features h3,
    .privacy-section h3,
    .contact h3 {
        font-size: 1.75rem;
    }

    .feature-card {
        padding: var(--spacing-lg);
    }

    .policy-links {
        flex-direction: column;
        gap: var(--spacing-sm);
    }

    .policy-link {
        width: 100%;
        max-width: 320px;
    }

    .policy-content {
        padding: var(--spacing-lg);
        border-radius: var(--radius-md);
    }

    .policy-content h2 {
        font-size: 2rem;
    }

    .policy-content h3 {
        font-size: 1.5rem;
    }

    .policy-content ul {
        margin-left: var(--spacing-md);
    }

    .email-link {
        font-size: 1.125rem;
    }
}

/* 打印样式 */
@media print {
    header,
    footer,
    .lang-toggle,
    .cta-buttons,
    .policy-links {
        display: none;
    }

    .policy-content {
        box-shadow: none;
        padding: 0;
        border: none;
    }

    body {
        font-size: 12pt;
        line-height: 1.6;
        background: white;
    }

    a {
        color: var(--text-primary);
        text-decoration: underline;
    }
}

/* 无障碍支持 */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* 高对比度模式 */
@media (prefers-contrast: high) {
    :root {
        --primary-color: #0052a3;
        --text-primary: #000000;
        --border-color: #000000;
    }

    .btn-primary,
    .btn-secondary,
    .policy-link,
    .feature-card {
        border-width: 2px;
    }
}

/* 暗色模式支持 */
@media (prefers-color-scheme: dark) {
    :root {
        --bg-white: #1a1a2e;
        --bg-light: #16213e;
        --bg-gray: #0f1729;
        --bg-card: #16213e;
        --text-primary: #f7fafc;
        --text-secondary: #cbd5e0;
        --text-tertiary: #a0aec0;
        --text-light: #718096;
        --border-color: #2d3748;
        --border-light: #1f2937;
        --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3), 0 1px 2px rgba(0, 0, 0, 0.2);
        --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.3), 0 2px 4px rgba(0, 0, 0, 0.2);
        --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.4), 0 4px 10px rgba(0, 0, 0, 0.3);
        --shadow-xl: 0 20px 40px rgba(0, 0, 0, 0.5), 0 8px 16px rgba(0, 0, 0, 0.4);
    }

    body {
        background: linear-gradient(180deg, var(--bg-white) 0%, var(--bg-light) 100%);
    }

    header {
        background: rgba(26, 26, 46, 0.95);
        backdrop-filter: blur(20px) saturate(180%);
    }

    .feature-card {
        background: var(--bg-card);
        border-color: var(--border-color);
    }

    .policy-content {
        background: var(--bg-card);
        border-color: var(--border-color);
    }

    footer {
        background: linear-gradient(135deg, #0f1729 0%, #1a1a2e 100%);
    }
}

/* 加载动画 - 可选 */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.feature-card {
    animation: fadeInUp 0.6s ease-out backwards;
}

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

/* 滚动条美化 */
::-webkit-scrollbar {
    width: 12px;
    height: 12px;
}

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

::-webkit-scrollbar-thumb {
    background: linear-gradient(180deg, var(--primary-color), var(--accent-color));
    border-radius: var(--radius-full);
    border: 3px solid var(--bg-light);
}

::-webkit-scrollbar-thumb:hover {
    background: linear-gradient(180deg, var(--primary-dark), var(--primary-color));
}

/* 选中文本样式 */
::selection {
    background: var(--primary-lighter);
    color: var(--primary-dark);
}

::-moz-selection {
    background: var(--primary-lighter);
    color: var(--primary-dark);
}