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

:root {
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary-color: #64748b;
    --secondary-hover: #475569;
    --success-color: #10b981;
    --danger-color: #ef4444;
    --bg-color: #ffffff;
    --bg-secondary: #f8fafc;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 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: 8px;
    --radius-lg: 12px;
    --transition: all 0.3s ease;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue', sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-color);
}

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

/* 导航栏 - 统一风格（与tianliu.ai一致） */
.navbar {
    background: #374151; /* gray-700 */
    box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    position: sticky;
    top: 0;
    z-index: 1000;
    padding: 0.5rem 0;
    border-bottom: 1px solid rgba(0, 0, 0, 0.1);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

.nav-brand {
    display: flex;
    align-items: center;
    text-decoration: none;
}

.nav-brand h1 {
    font-size: 1.25rem;
    color: white;
    font-weight: 700;
    margin: 0;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.lang-switcher {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 0.5rem;
    margin-right: 0.75rem;
}

.lang-btn {
    padding: 0.125rem 0.375rem;
    border: none;
    background: #4b5563; /* gray-600 */
    color: white;
    border-radius: 0.25rem;
    cursor: pointer;
    font-size: 0.75rem;
    transition: var(--transition);
    min-width: 3.5rem;
    height: 1.25rem;
    display: flex;
    align-items: center;
    justify-content: center;
}

.lang-btn:hover {
    background: #6b7280; /* gray-500 */
}

.lang-btn.active {
    background: #3b82f6; /* blue-500 */
}

.nav-actions {
    display: flex;
    gap: 0.5rem;
    align-items: center;
}

.user-info {
    color: white;
    font-size: 0.875rem;
    margin-right: 0.5rem;
}

/* 按钮样式 - 统一风格（与tianliu.ai一致） */
.btn {
    padding: 0.25rem 0.5rem;
    border: none;
    border-radius: 0.375rem 0.375rem 0 0.375rem; /* rounded-t-none rounded-b-md */
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
    display: inline-block;
    text-align: center;
    box-shadow: 0 1px 2px 0 rgba(0, 0, 0, 0.25);
    background: linear-gradient(to bottom, #0ea5e9, #1e40af); /* sky-600 to blue-800 */
    color: white;
    line-height: 1.25rem;
    white-space: nowrap;
}

.btn-primary {
    background: linear-gradient(to bottom, #0ea5e9, #1e40af); /* sky-600 to blue-800 */
    color: white;
}

.btn-primary:hover {
    background: linear-gradient(to bottom, #f43f5e, #991b1b); /* rose-500 to red-800 */
    transform: translateY(-1px);
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

.btn-secondary {
    background: linear-gradient(to bottom, #f97316, #ea580c); /* orange-500 to orange-700 */
    color: white;
}

.btn-secondary:hover {
    background: linear-gradient(to bottom, #fb923c, #f97316); /* orange-400 to orange-500 */
}

.btn-outline {
    background: transparent;
    color: white;
    border: 2px solid white;
    box-shadow: none;
}

.btn-outline:hover {
    background: rgba(255, 255, 255, 0.1);
    color: white;
}

.btn-large {
    padding: 1rem 2rem;
    font-size: 1.125rem;
}

.btn-small {
    padding: 0.375rem 0.75rem;
    font-size: 0.875rem;
}

/* Hero区域 */
.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 6rem 0;
    text-align: center;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 800;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.75rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    opacity: 0.95;
}

.hero-tagline {
    font-size: 1.5rem;
    margin-bottom: 2rem;
    font-weight: 500;
}

.hero-features {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.hero-features p {
    font-size: 1.125rem;
    opacity: 0.9;
}

.hero-description {
    font-size: 1.25rem;
    margin-bottom: 2.5rem;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
    opacity: 0.9;
}

.hero-actions {
    display: flex;
    justify-content: center;
    gap: 1rem;
    flex-wrap: wrap;
}

/* 章节样式 */
section {
    padding: 5rem 0;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 3rem;
    color: var(--text-primary);
}

/* 特性网格 */
.features {
    background: var(--bg-secondary);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.feature-card {
    background: white;
    padding: 2rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    transition: var(--transition);
}

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

.feature-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--primary-color);
}

.feature-card p {
    color: var(--text-secondary);
    line-height: 1.8;
}

/* 工作流程 */
.how-it-works {
    text-align: center;
}

.workflow {
    max-width: 800px;
    margin: 0 auto;
}

.workflow-step {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 2rem;
    padding: 1.5rem;
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
}

.workflow-features {
    list-style: none;
    display: flex;
    justify-content: center;
    gap: 2rem;
    flex-wrap: wrap;
}

.workflow-features li {
    padding: 0.75rem 1.5rem;
    background: white;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    color: var(--text-primary);
}

/* 可靠性 */
.reliability {
    background: var(--bg-secondary);
}

.reliability h3 {
    font-size: 1.75rem;
    text-align: center;
    margin-bottom: 2rem;
    color: var(--text-primary);
}

.reliability-list {
    list-style: none;
    max-width: 600px;
    margin: 0 auto;
    display: grid;
    gap: 1rem;
}

.reliability-list li {
    padding: 1rem 1.5rem;
    background: white;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    border-left: 4px solid var(--primary-color);
}

/* 日常使用 */
.everyday h3 {
    font-size: 1.75rem;
    text-align: center;
    margin-bottom: 2rem;
    color: var(--text-primary);
}

.everyday-list {
    list-style: none;
    max-width: 600px;
    margin: 0 auto;
    display: grid;
    gap: 1rem;
}

.everyday-list li {
    padding: 1rem 1.5rem;
    background: var(--bg-secondary);
    border-radius: var(--radius);
    border-left: 4px solid var(--success-color);
}

/* 适用人群 */
.audience {
    background: var(--bg-secondary);
}

.audience-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.audience-card {
    background: white;
    padding: 2rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    text-align: center;
    transition: var(--transition);
}

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

.audience-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--primary-color);
}

.audience-card p {
    color: var(--text-secondary);
    line-height: 1.8;
}

/* 产品版本 */
.products-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    max-width: 800px;
    margin: 0 auto;
}

.product-card {
    background: white;
    padding: 2.5rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    border: 2px solid var(--border-color);
    transition: var(--transition);
}

.product-card:hover {
    border-color: var(--primary-color);
    transform: translateY(-5px);
}

.product-card h3 {
    font-size: 1.75rem;
    margin-bottom: 1.5rem;
    color: var(--primary-color);
}

.product-features {
    list-style: none;
}

.product-features li {
    padding: 0.75rem 0;
    color: var(--text-secondary);
    border-bottom: 1px solid var(--border-color);
}

.product-features li:last-child {
    border-bottom: none;
}

/* 品牌主张 */
.brand {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    text-align: center;
}

.brand .section-title {
    color: white;
}

.brand-statement {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    opacity: 0.95;
}

.brand-highlight {
    font-size: 2rem;
    font-weight: 700;
    margin-top: 1rem;
}

/* 行动号召 */
.cta {
    background: var(--bg-secondary);
    text-align: center;
}

.cta-actions {
    display: flex;
    justify-content: center;
    gap: 1rem;
    flex-wrap: wrap;
}

/* 页脚 - 统一风格（与tianliu.ai一致） */
.footer {
    background: #111827; /* gray-900 */
    color: white;
    padding: 1.5rem 0;
    margin-top: 2rem;
}

.footer .container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
    text-align: center;
}

.footer-copyright {
    font-size: 0.875rem;
    margin: 0 0 0.5rem 0;
    color: white;
}

.footer-links {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: center;
    gap: 1.5rem 0.5rem;
    margin-top: 0.5rem;
    font-size: 0.875rem;
    color: #d1d5db; /* gray-200 */
}

.footer-link {
    color: #d1d5db; /* gray-200 */
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    transition: var(--transition);
}

.footer-link:hover {
    color: white;
}

.footer-link svg {
    flex-shrink: 0;
}

/* 模态框 */
.modal {
    display: none;
    position: fixed;
    z-index: 2000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
}

.modal-content {
    background-color: white;
    margin: 5% auto;
    padding: 2rem;
    border-radius: var(--radius-lg);
    width: 90%;
    max-width: 500px;
    box-shadow: var(--shadow-lg);
    position: relative;
    animation: modalSlideIn 0.3s ease;
}

@keyframes modalSlideIn {
    from {
        transform: translateY(-50px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

.modal-close {
    position: absolute;
    right: 1rem;
    top: 1rem;
    font-size: 2rem;
    font-weight: bold;
    color: var(--text-secondary);
    cursor: pointer;
    line-height: 1;
    transition: var(--transition);
}

.modal-close:hover {
    color: var(--text-primary);
}

.modal-content h2 {
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

/* 表单样式 */
.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
    font-weight: 500;
}

.form-group input {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    font-size: 1rem;
    transition: var(--transition);
}

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

.modal-switch {
    margin-top: 1.5rem;
    text-align: center;
    color: var(--text-secondary);
}

.modal-switch a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
}

.modal-switch a:hover {
    text-decoration: underline;
}

/* 设备列表 */
.device-list {
    margin-top: 1rem;
}

.device-item {
    padding: 1.5rem;
    background: var(--bg-secondary);
    border-radius: var(--radius);
    margin-bottom: 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.device-item h4 {
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.device-item p {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.5rem;
    }
    
    .hero-tagline {
        font-size: 1.25rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .nav-menu {
        flex-wrap: wrap;
        gap: 0.5rem;
    }
    
    .lang-switcher {
        margin-right: 0;
        grid-template-columns: repeat(2, 1fr);
    }
    
    .nav-actions {
        flex-wrap: wrap;
    }
    
    .features-grid,
    .audience-grid,
    .products-grid {
        grid-template-columns: 1fr;
    }
    
    .workflow-features {
        flex-direction: column;
        gap: 1rem;
    }
    
    .hero-features {
        flex-direction: column;
        gap: 1rem;
    }
    
    .modal-content {
        width: 95%;
        margin: 10% auto;
        padding: 1.5rem;
    }
}

@media (max-width: 480px) {
    .hero {
        padding: 4rem 0;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .section-title {
        font-size: 1.75rem;
    }
    
    .btn-large {
        padding: 0.875rem 1.5rem;
        font-size: 1rem;
    }
}