/* ==========================================================================
   全局样式和变量
   ========================================================================== */
:root {
    --color-primary: #3b82f6;
    --color-primary-dark: #2563eb;
    --color-secondary: #10b981;
    --color-accent: #f59e0b;
    --color-text-primary: #111827;
    --color-text-secondary: #6b7280;
    --color-bg-main: #ffffff;
    --color-bg-light: #f9fafb;
    --color-bg-dark: #1f2937;
    --color-border: #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);
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    color: var(--color-text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

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

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

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 20px;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 20px;
    font-weight: 700;
    color: var(--color-text-primary);
    text-decoration: none;
}

.logo-small {
    width: 40px;
    height: 40px;
}

.brand-name {
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 32px;
    align-items: center;
}

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

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

.nav-menu a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--color-primary);
    transition: width 0.3s ease;
}

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

.nav-right {
    display: flex;
    align-items: center;
}

.lang-selector {
    padding: 8px 12px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    background: white;
    color: var(--color-text-primary);
    font-size: 14px;
    cursor: pointer;
    transition: all 0.3s ease;
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%23333' d='M6 9L1 4h10z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 8px center;
    padding-right: 32px;
}

.lang-selector:hover {
    border-color: var(--color-primary);
}

.lang-selector:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
}

.nav-toggle span {
    width: 24px;
    height: 2px;
    background: var(--color-text-primary);
    transition: all 0.3s ease;
}

/* ==========================================================================
   英雄区域
   ========================================================================== */
.hero {
    margin-top: 80px;
    padding: 80px 0;
    background: linear-gradient(135deg, #f0f9ff 0%, #e0f2fe 100%);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -10%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(59, 130, 246, 0.1) 0%, transparent 70%);
    border-radius: 50%;
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
    position: relative;
    z-index: 1;
}

.hero-title {
    font-size: 56px;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 24px;
    color: var(--color-text-primary);
}

.gradient-text {
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-description {
    font-size: 20px;
    color: var(--color-text-secondary);
    margin-bottom: 32px;
    line-height: 1.8;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 28px;
    border-radius: var(--radius-md);
    font-size: 16px;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
}

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

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

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

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

.hero-image {
    position: relative;
}

.demo-container {
    display: flex;
    align-items: center;
    gap: 24px;
    background: white;
    padding: 32px;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
}

.demo-browser {
    flex: 1;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    background: white;
}

.browser-header {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px;
    background: var(--color-bg-light);
    border-bottom: 1px solid var(--color-border);
}

.browser-dots {
    display: flex;
    gap: 6px;
}

.browser-dots span {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: var(--color-border);
}

.browser-dots span:nth-child(1) { background: #ff5f57; }
.browser-dots span:nth-child(2) { background: #ffbd2e; }
.browser-dots span:nth-child(3) { background: #28ca42; }

.browser-url {
    flex: 1;
    padding: 6px 12px;
    background: white;
    border-radius: 4px;
    font-size: 12px;
    color: var(--color-text-secondary);
}

.browser-content {
    padding: 20px;
}

.page-content {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.product-item {
    padding: 12px;
    background: var(--color-bg-light);
    border-radius: var(--radius-md);
    font-size: 14px;
}

.arrow {
    font-size: 32px;
    color: var(--color-primary);
    font-weight: bold;
}

.demo-table {
    flex: 1;
    min-width: 200px;
}

.demo-table table {
    width: 100%;
    border-collapse: collapse;
    font-size: 14px;
}

.demo-table th,
.demo-table td {
    padding: 10px;
    text-align: left;
    border: 1px solid var(--color-border);
}

.demo-table th {
    background: var(--color-primary);
    color: white;
    font-weight: 600;
}

.demo-table tr:nth-child(even) {
    background: var(--color-bg-light);
}

/* ==========================================================================
   功能区域
   ========================================================================== */
.features {
    padding: 100px 0;
    background: white;
}

.section-title {
    font-size: 42px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 16px;
    color: var(--color-text-primary);
}

.section-subtitle {
    text-align: center;
    font-size: 20px;
    color: var(--color-text-secondary);
    margin-bottom: 60px;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 32px;
    margin-top: 60px;
}

.feature-card {
    padding: 32px;
    background: white;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    transition: all 0.3s ease;
}

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

.feature-icon {
    font-size: 48px;
    margin-bottom: 16px;
}

.feature-card h3 {
    font-size: 24px;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--color-text-primary);
}

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

/* ==========================================================================
   工作原理
   ========================================================================== */
.how-it-works {
    padding: 100px 0;
    background: var(--color-bg-light);
}

.steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-top: 60px;
}

.step {
    display: flex;
    gap: 24px;
    align-items: flex-start;
}

.step-number {
    flex-shrink: 0;
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    font-weight: 700;
    box-shadow: var(--shadow-md);
}

.step-content h3 {
    font-size: 24px;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--color-text-primary);
}

.step-content p {
    color: var(--color-text-secondary);
    line-height: 1.7;
}

/* ==========================================================================
   下载区域
   ========================================================================== */
.download {
    padding: 100px 0;
    background: white;
}

.download-options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 32px;
    margin-top: 60px;
}

.download-card {
    padding: 40px;
    background: var(--color-bg-light);
    border-radius: var(--radius-lg);
    text-align: center;
    border: 2px solid transparent;
    transition: all 0.3s ease;
}

.download-card:hover {
    border-color: var(--color-primary);
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.download-icon {
    font-size: 64px;
    margin-bottom: 24px;
}

.download-card h3 {
    font-size: 24px;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--color-text-primary);
}

.download-card p {
    color: var(--color-text-secondary);
    margin-bottom: 24px;
}

.requirements {
    margin-top: 60px;
    padding: 32px;
    background: var(--color-bg-light);
    border-radius: var(--radius-lg);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.requirements h4 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 16px;
    color: var(--color-text-primary);
}

.requirements ul {
    list-style: none;
    padding-left: 0;
}

.requirements li {
    padding: 8px 0;
    color: var(--color-text-secondary);
    position: relative;
    padding-left: 24px;
}

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

/* ==========================================================================
   联系区域
   ========================================================================== */
.contact {
    padding: 100px 0;
    background: var(--color-bg-light);
}

.contact-info {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-top: 60px;
}

.contact-item {
    text-align: center;
    padding: 32px;
    background: white;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
}

.contact-icon {
    font-size: 48px;
    margin-bottom: 16px;
}

.contact-item h4 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--color-text-primary);
}

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

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

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 40px;
    flex-wrap: wrap;
    gap: 32px;
}

.footer-brand {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 20px;
    font-weight: 700;
}

.footer-links {
    display: flex;
    gap: 32px;
    flex-wrap: wrap;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-links a:hover {
    color: white;
}

.footer-bottom {
    text-align: center;
    padding-top: 20px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: rgba(255, 255, 255, 0.6);
}

/* ==========================================================================
   响应式设计
   ========================================================================== */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 70px;
        left: -100%;
        flex-direction: column;
        background: white;
        width: 100%;
        padding: 20px;
        box-shadow: var(--shadow-lg);
        transition: left 0.3s ease;
    }

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

    .nav-right {
        order: -1;
        margin-right: auto;
    }

    .lang-selector {
        font-size: 13px;
        padding: 6px 10px;
        padding-right: 28px;
    }

    .nav-toggle {
        display: flex;
    }

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

    .hero-title {
        font-size: 36px;
    }

    .hero-description {
        font-size: 18px;
    }

    .demo-container {
        flex-direction: column;
        padding: 20px;
    }

    .arrow {
        transform: rotate(90deg);
    }

    .section-title {
        font-size: 32px;
    }

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

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

    .download-options {
        grid-template-columns: 1fr;
    }

    .footer-content {
        flex-direction: column;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 28px;
    }

    .hero-description {
        font-size: 16px;
    }

    .btn {
        padding: 12px 24px;
        font-size: 14px;
    }

    .section-title {
        font-size: 28px;
    }
}