/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #635BFF;
    --primary-dark: #5851E6;
    --secondary-color: #00D924;
    --text-dark: #0A2540;
    --text-gray: #425466;
    --bg-light: #F6F9FC;
    --bg-white: #FFFFFF;
    --border-color: #E3E8EF;
    --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
    --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);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background-color: var(--bg-white);
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

/* Header & Navigation */
.header {
    background: var(--bg-white);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.navbar {
    padding: 1rem 0;
}

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

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

.nav-brand h1 {
    font-size: 1.25rem;
    color: var(--text-dark);
    font-weight: 600;
    margin: 0;
}

.nav-brand .brand-url {
    font-size: 0.875rem;
    color: var(--text-gray);
    text-decoration: none;
    font-weight: 400;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
}

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

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

.btn-primary {
    background: var(--primary-color);
    color: white;
    padding: 0.5rem 1.5rem;
    border-radius: 0.5rem;
    text-decoration: none;
    font-weight: 600;
    transition: background 0.3s;
    display: inline-block;
}

.btn-primary:hover {
    background: var(--primary-dark);
}

/* Hero Section */
.hero {
    padding: 6rem 0;
    background: linear-gradient(180deg, #635BFF 0%, #0A2540 100%);
    color: white;
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    align-items: center;
}

.hero-title {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    opacity: 0.95;
}

.hero-features {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    margin-bottom: 2rem;
}

.feature-tag {
    background: rgba(255, 255, 255, 0.2);
    padding: 0.5rem 1rem;
    border-radius: 2rem;
    font-size: 0.9rem;
    backdrop-filter: blur(10px);
}

.hero-cta {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.btn-large {
    background: white;
    color: var(--primary-color);
    padding: 1rem 2rem;
    border-radius: 0.5rem;
    text-decoration: none;
    font-weight: 700;
    font-size: 1.1rem;
    transition: transform 0.3s, box-shadow 0.3s;
    display: inline-block;
}

.btn-large:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl);
}

.btn-secondary {
    background: transparent;
    color: white;
    padding: 1rem 2rem;
    border: 2px solid white;
    border-radius: 0.5rem;
    text-decoration: none;
    font-weight: 600;
    font-size: 1.1rem;
    transition: background 0.3s;
    display: inline-block;
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.1);
}

.hero-image {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 100%;
}

.image-comparison-slider {
    width: 100%;
    max-width: 900px;
    position: relative;
    border-radius: 1rem;
    overflow: hidden;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
}

.comparison-wrapper {
    position: relative;
    width: 100%;
    height: 600px;
    cursor: grab;
    user-select: none;
    border-radius: 1rem;
    overflow: hidden;
}

.comparison-wrapper:active {
    cursor: grabbing;
}

.image-before-full,
.image-after-full {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
}

.image-before-full {
    z-index: 1;
}

.image-after-full {
    z-index: 2;
    clip-path: inset(0 50% 0 0);
    transition: clip-path 0.1s ease-out;
}

.image-content {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center;
    display: block;
}

.slider-handle {
    position: absolute;
    top: 0;
    left: 50%;
    width: 4px;
    height: 100%;
    background: white;
    z-index: 10;
    transform: translateX(-50%);
    cursor: ew-resize;
    box-shadow: 0 0 20px rgba(0, 0, 0, 0.5);
}

.slider-line {
    position: absolute;
    top: 0;
    left: 50%;
    width: 2px;
    height: 100%;
    background: white;
    transform: translateX(-50%);
}

.slider-button {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 48px;
    height: 48px;
    background: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    color: var(--primary-color);
}

.comparison-label-left,
.comparison-label-right {
    position: absolute;
    top: 1rem;
    background: rgba(0, 0, 0, 0.6);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    font-size: 0.875rem;
    font-weight: 600;
    z-index: 20;
    backdrop-filter: blur(10px);
}

.comparison-label-left {
    left: 1rem;
}

.comparison-label-right {
    right: 1rem;
}

.demo-box {
    background: white;
    border-radius: 1rem;
    padding: 2rem;
    box-shadow: var(--shadow-xl);
    width: 100%;
    max-width: 500px;
}

.demo-image-placeholder {
    background: var(--bg-light);
    border: 2px dashed var(--border-color);
    border-radius: 0.5rem;
    padding: 3rem;
    text-align: center;
    color: var(--text-gray);
}

/* Section Styles */
section {
    padding: 4rem 0;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 800;
    text-align: center;
    margin-bottom: 1rem;
    color: var(--text-dark);
}

.section-subtitle {
    text-align: center;
    color: var(--text-gray);
    font-size: 1.1rem;
    margin-bottom: 3rem;
}

/* Features Section */
.features {
    background: var(--bg-light);
}

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

.feature-card {
    background: white;
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: var(--shadow-md);
    transition: transform 0.3s, box-shadow 0.3s;
}

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

.feature-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

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

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

/* How It Works Section */
.steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.step {
    text-align: center;
    padding: 2rem;
}

.step-number {
    width: 60px;
    height: 60px;
    background: var(--primary-color);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
    margin: 0 auto 1.5rem;
}

.step h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--text-dark);
}

.step p {
    color: var(--text-gray);
    line-height: 1.8;
}

.cta-center {
    text-align: center;
}

/* Use Cases Section */
.use-cases {
    background: var(--bg-light);
}

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

.use-case-card {
    background: white;
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: var(--shadow-md);
    transition: transform 0.3s, box-shadow 0.3s;
}

.use-case-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

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

.use-case-card p {
    color: var(--text-gray);
    margin-bottom: 1.5rem;
    line-height: 1.8;
}

.use-case-card ul {
    list-style: none;
    padding-left: 0;
}

.use-case-card li {
    padding: 0.5rem 0;
    color: var(--text-gray);
    position: relative;
    padding-left: 1.5rem;
}

.use-case-card li:before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--secondary-color);
    font-weight: bold;
}

/* FAQ Section */
.faq-list {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    background: white;
    padding: 2rem;
    border-radius: 0.5rem;
    margin-bottom: 1rem;
    box-shadow: var(--shadow-sm);
    border-left: 4px solid var(--primary-color);
}

.faq-item h3 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
    color: var(--text-dark);
}

.faq-item p {
    color: var(--text-gray);
    line-height: 1.8;
}

/* CTA Section */
.cta-section {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    text-align: center;
    padding: 4rem 0;
}

.cta-section h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.cta-section p {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    opacity: 0.95;
}

/* Footer */
.footer {
    background: #0A2540;
    color: white;
    padding: 4rem 0 2rem;
}

.footer-languages {
    margin-top: 3rem;
    padding-top: 3rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-languages h4 {
    margin-bottom: 1.5rem;
    color: white;
    font-size: 0.875rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.language-pairs {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 0.75rem;
    font-size: 0.875rem;
}

.language-pairs a {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    transition: color 0.2s;
    display: block;
}

.language-pairs a:hover {
    color: white;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h3,
.footer-section h4 {
    margin-bottom: 1rem;
    color: white;
}

.footer-section p {
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.8;
}

.footer-section ul {
    list-style: none;
}

.footer-section ul li {
    margin-bottom: 0.5rem;
}

.footer-section a {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    transition: color 0.3s;
}

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

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: rgba(255, 255, 255, 0.7);
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
    }
    
    .hero .container {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-subtitle {
        font-size: 1rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .features-grid,
    .use-cases-grid {
        grid-template-columns: 1fr;
    }
    
    .steps {
        grid-template-columns: 1fr;
    }
    
    .hero-cta {
        flex-direction: column;
    }
    
    .btn-large,
    .btn-secondary {
        width: 100%;
        text-align: center;
    }
    
    .image-comparison-slider {
        max-width: 100%;
    }
    
    .comparison-wrapper {
        height: 400px;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .hero {
        padding: 2rem 0;
    }
    
    section {
        padding: 2rem 0;
    }
    
    .hero-title {
        font-size: 1.75rem;
    }
}