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

:root {
    /* Grok Official Colors */
    --primary-color: #FF6B35;        /* Grok orange */
    --secondary-color: #1C1C28;      /* Dark blue/black */
    --accent-color: #4F46E5;         /* Blue accent */
    --bg-primary: #0A0A0F;           /* Very dark background */
    --bg-secondary: #1A1A24;         /* Slightly lighter dark */
    --bg-light: #F8FAFC;            /* Light background */
    --text-primary: #FFFFFF;         /* Primary text (white) */
    --text-secondary: #94A3B8;       /* Secondary text (gray) */
    --text-dark: #1E293B;            /* Dark text */
    --border-color: #334155;         /* Border color */
    --hover-color: #FF8A5B;          /* Orange hover */
    
    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size-4xl: 2.25rem;
    --font-size-5xl: 3rem;
    
    /* Spacing */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-5: 1.25rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-10: 2.5rem;
    --space-12: 3rem;
    --space-16: 4rem;
    --space-20: 5rem;
    --space-24: 6rem;
    
    /* Border radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --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);
}

html {
    scroll-behavior: smooth;
}

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

/* Utility Classes */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-4);
}

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

.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* Button Styles */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-3) var(--space-6);
    border: 2px solid transparent;
    border-radius: var(--radius-lg);
    font-size: var(--font-size-base);
    font-weight: 600;
    text-decoration: none;
    transition: all 0.3s ease;
    cursor: pointer;
    white-space: nowrap;
    min-height: 48px;
}

.btn--primary {
    background: linear-gradient(135deg, var(--primary-color), var(--hover-color));
    color: white;
    box-shadow: var(--shadow-md);
}

.btn--primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
    background: linear-gradient(135deg, var(--hover-color), var(--primary-color));
}

.btn--secondary {
    background: transparent;
    color: var(--text-primary);
    border-color: var(--border-color);
}

.btn--secondary:hover {
    background: var(--bg-secondary);
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.btn--outline {
    background: transparent;
    color: var(--primary-color);
    border-color: var(--primary-color);
}

.btn--outline:hover {
    background: var(--primary-color);
    color: white;
}

/* Header Styles */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(10, 10, 15, 0.95);
    backdrop-filter: blur(20px);
    z-index: 1000;
    border-bottom: 1px solid var(--border-color);
}

.nav {
    padding: var(--space-4) 0;
}

.nav__container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-4);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav__brand-link {
    text-decoration: none;
    transition: opacity 0.3s ease;
}

.nav__brand-link:hover {
    opacity: 0.8;
}

.nav__brand {
    font-size: var(--font-size-2xl);
    font-weight: 800;
    color: var(--primary-color);
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav__menu {
    display: flex;
    list-style: none;
    align-items: center;
    gap: var(--space-8);
}

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

.nav__link:hover {
    color: var(--primary-color);
}

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

.nav__link:hover::after {
    width: 100%;
}

.nav__cta {
    background: linear-gradient(135deg, var(--primary-color), var(--hover-color));
    color: white !important;
    padding: var(--space-2) var(--space-4);
    border-radius: var(--radius-md);
    font-weight: 600;
}

.nav__cta::after {
    display: none;
}

.nav__cta:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.nav__toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
    width: 24px;
    height: 18px;
    justify-content: space-between;
}

.nav__toggle span {
    width: 100%;
    height: 2px;
    background: var(--text-primary);
    transition: all 0.3s ease;
}

.nav__toggle--active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.nav__toggle--active span:nth-child(2) {
    opacity: 0;
}

.nav__toggle--active span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -6px);
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    background: linear-gradient(135deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
    overflow: hidden;
    padding-top: 80px;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 50% 50%, rgba(255, 107, 53, 0.08) 0%, transparent 70%),
                radial-gradient(circle at 30% 80%, rgba(79, 70, 229, 0.05) 0%, transparent 60%);
    pointer-events: none;
}

.hero__container {
    max-width: 1000px;
    margin: 0 auto;
    padding: var(--space-12) var(--space-4);
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    gap: var(--space-12);
    position: relative;
    z-index: 2;
}

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

.hero__title {
    font-size: var(--font-size-5xl);
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: var(--space-6);
    background: linear-gradient(135deg, var(--text-primary) 0%, var(--primary-color) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-align: center;
}

.hero__subtitle {
    font-size: var(--font-size-xl);
    color: var(--text-secondary);
    margin-bottom: var(--space-8);
    line-height: 1.6;
    text-align: center;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.hero__features {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-3);
    margin-bottom: 0;
    justify-content: center;
    align-items: center;
}

.hero__feature {
    background: rgba(255, 107, 53, 0.1);
    color: var(--primary-color);
    padding: var(--space-2) var(--space-4);
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    font-weight: 600;
    border: 1px solid rgba(255, 107, 53, 0.2);
}

.hero__actions {
    display: flex;
    gap: var(--space-4);
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
}

/* Hero Chat Component */
.hero__chat {
    width: 100%;
    max-width: 700px;
    margin: 0 auto;
}

/* Hero CTA Section */
.hero__cta {
    text-align: center;
    margin-top: var(--space-8);
}

.hero__cta-text {
    font-size: var(--font-size-lg);
    color: var(--text-secondary);
    margin-bottom: var(--space-6);
    font-weight: 500;
}

/* Video Section */
.video-section {
    padding: var(--space-24) 0;
    background: var(--bg-primary);
    position: relative;
}

.video-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 50% 50%, rgba(255, 107, 53, 0.05) 0%, transparent 70%);
    pointer-events: none;
}

.video-section__container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-4);
    position: relative;
    z-index: 1;
}

.video-section__header {
    text-align: center;
    margin-bottom: var(--space-16);
}

.video-section__title {
    font-size: var(--font-size-4xl);
    font-weight: 700;
    margin-bottom: var(--space-4);
    color: var(--text-primary);
}

.video-section__subtitle {
    font-size: var(--font-size-xl);
    color: var(--text-secondary);
    max-width: 700px;
    margin: 0 auto;
    line-height: 1.6;
}

.video-section__content {
    display: flex;
    justify-content: center;
    align-items: center;
}

.video-wrapper {
    position: relative;
    width: 100%;
    max-width: 900px;
    aspect-ratio: 16 / 9;
    border-radius: var(--radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-2xl);
    border: 1px solid var(--border-color);
    background: var(--bg-secondary);
    transition: all 0.3s ease;
}

.video-wrapper:hover {
    transform: translateY(-8px);
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
}

.video-iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: none;
    border-radius: var(--radius-xl);
}

/* Features Section */
.features {
    padding: var(--space-24) 0;
    background: var(--bg-secondary);
}

.features__container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-4);
}

.features__header {
    text-align: center;
    margin-bottom: var(--space-16);
}

.features__title {
    font-size: var(--font-size-4xl);
    font-weight: 700;
    margin-bottom: var(--space-4);
    color: var(--text-primary);
}

.features__subtitle {
    font-size: var(--font-size-xl);
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

.features__grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: var(--space-8);
}

.feature {
    background: var(--bg-primary);
    padding: var(--space-8);
    border-radius: var(--radius-xl);
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.feature::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
    opacity: 0;
    transition: opacity 0.3s ease;
}

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

.feature:hover::before {
    opacity: 1;
}

.feature__icon {
    width: 64px;
    height: 64px;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--space-6);
    color: white;
}

.feature__title {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: var(--space-4);
    color: var(--text-primary);
}

.feature__description {
    color: var(--text-secondary);
    line-height: 1.6;
}

/* How It Works Section */
.how-it-works {
    padding: var(--space-24) 0;
    background: var(--bg-primary);
}

.how-it-works__container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-4);
}

.how-it-works__header {
    text-align: center;
    margin-bottom: var(--space-16);
}

.how-it-works__title {
    font-size: var(--font-size-4xl);
    font-weight: 700;
    margin-bottom: var(--space-4);
    color: var(--text-primary);
}

.how-it-works__subtitle {
    font-size: var(--font-size-xl);
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

.workflow {
    display: flex;
    align-items: flex-start;
    gap: var(--space-8);
    margin-bottom: var(--space-16);
}

.workflow__step {
    flex: 1;
    text-align: center;
}

.workflow__number {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--font-size-2xl);
    font-weight: 700;
    color: white;
    margin: 0 auto var(--space-6);
    box-shadow: var(--shadow-lg);
}

.workflow__title {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: var(--space-4);
    color: var(--text-primary);
}

.workflow__description {
    color: var(--text-secondary);
    line-height: 1.6;
}

.workflow__connector {
    width: 2px;
    height: 60px;
    background: linear-gradient(180deg, var(--primary-color), var(--accent-color));
    margin-top: 40px;
    flex-shrink: 0;
}

/* Demo Section */
.demo-section {
    margin-top: var(--space-16);
    text-align: center;
}

.demo-section__title {
    font-size: var(--font-size-2xl);
    font-weight: 600;
    margin-bottom: var(--space-8);
    color: var(--text-primary);
}

.benchmarks {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: var(--space-8);
    max-width: 800px;
    margin: 0 auto;
}

.benchmark {
    background: var(--bg-primary);
    padding: var(--space-6);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

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

.benchmark__metric {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: var(--space-2);
}

.benchmark__label {
    font-size: var(--font-size-base);
    color: var(--text-secondary);
}

/* About Section */
.about {
    padding: var(--space-24) 0;
    background: var(--bg-secondary);
}

.about__container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-4);
}

.about__header {
    text-align: center;
    margin-bottom: var(--space-16);
}

.about__title {
    font-size: var(--font-size-4xl);
    font-weight: 700;
    margin-bottom: var(--space-4);
    color: var(--text-primary);
}

.about__subtitle {
    font-size: var(--font-size-xl);
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

.about__grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-16);
    align-items: start;
}

.about__text {
    space-y: var(--space-8);
}

.about__section {
    margin-bottom: var(--space-8);
}

.about__section-title {
    font-size: var(--font-size-xl);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--space-4);
    position: relative;
    padding-left: 20px;
}

.about__section-title::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 4px;
    height: 20px;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    border-radius: 2px;
}

.about__description {
    color: var(--text-secondary);
    line-height: 1.7;
    font-size: var(--font-size-base);
}

.about__stats {
    background: var(--bg-primary);
    padding: var(--space-8);
    border-radius: var(--radius-xl);
    border: 1px solid var(--border-color);
    position: sticky;
    top: 100px;
}

.stats-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-6);
    margin-bottom: var(--space-8);
}

.stat-item {
    text-align: center;
    padding: var(--space-4);
    border-radius: var(--radius-lg);
    background: rgba(255, 107, 53, 0.1);
    border: 1px solid rgba(255, 107, 53, 0.2);
}

.stat-number {
    font-size: var(--font-size-3xl);
    font-weight: 800;
    color: var(--primary-color);
    margin-bottom: var(--space-2);
}

.stat-label {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
    font-weight: 500;
}

/* CTA Section Styles */
.cta {
    text-align: center;
    padding: var(--space-6);
    background: linear-gradient(135deg, rgba(255, 107, 53, 0.1), rgba(79, 70, 229, 0.1));
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
}

.cta__container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-4);
}

.cta__content {
    text-align: center;
}

.cta__title {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--space-3);
}

.cta__subtitle {
    color: var(--text-secondary);
    margin-bottom: var(--space-6);
    font-size: var(--font-size-sm);
}

.cta__actions {
    display: flex;
    gap: var(--space-4);
    justify-content: center;
    align-items: center;
    flex-wrap: wrap;
}

/* About CTA Section Styles (existing) */
.about__cta {
    text-align: center;
    padding: var(--space-6);
    background: linear-gradient(135deg, rgba(255, 107, 53, 0.1), rgba(79, 70, 229, 0.1));
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
}

.about__cta-title {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--space-3);
}

.about__cta-text {
    color: var(--text-secondary);
    margin-bottom: var(--space-6);
    font-size: var(--font-size-sm);
}

/* 添加按钮容器样式 */
.about__cta-buttons {
    display: flex;
    gap: var(--space-4);
    justify-content: center;
    align-items: center;
    flex-wrap: wrap;
}

/* FAQ Section */
.faq {
    padding: var(--space-24) 0;
    background: var(--bg-secondary);
}

.faq__container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-4);
}

.faq__header {
    text-align: center;
    margin-bottom: var(--space-20);
}

.faq__title {
    font-size: var(--font-size-4xl);
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--space-4);
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    background-clip: text;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.faq__subtitle {
    font-size: var(--font-size-lg);
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

.faq__grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(500px, 1fr));
    gap: var(--space-8);
    max-width: 1200px;
    margin: 0 auto;
}

.faq__category {
    background: var(--bg-primary);
    border-radius: 16px;
    padding: var(--space-8);
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
}

.faq__category:hover {
    transform: translateY(-4px);
    border-color: var(--primary-color);
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.15);
}

.faq__category-title {
    font-size: var(--font-size-xl);
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: var(--space-6);
    padding-bottom: var(--space-3);
    border-bottom: 2px solid var(--primary-color);
    position: relative;
}

.faq__category-title::before {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 50px;
    height: 2px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
}

.faq__item {
    margin-bottom: var(--space-4);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    overflow: hidden;
    transition: all 0.3s ease;
    background: var(--bg-primary);
}

.faq__item:hover {
    border-color: var(--primary-color);
    box-shadow: 0 2px 12px rgba(255, 107, 53, 0.1);
}

.faq__item:last-child {
    margin-bottom: 0;
}

.faq__question {
    width: 100%;
    padding: var(--space-5) var(--space-6);
    background: transparent;
    border: none;
    color: var(--text-primary);
    font-size: var(--font-size-md);
    font-weight: 600;
    text-align: left;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-family: inherit;
}

.faq__question:hover {
    color: var(--primary-color);
    background: var(--bg-secondary);
}

.faq__question:focus {
    outline: none;
    color: var(--primary-color);
    background: var(--bg-secondary);
}

.faq__icon {
    font-size: 1.5rem;
    font-weight: 300;
    color: var(--primary-color);
    transition: transform 0.3s ease;
    flex-shrink: 0;
    margin-left: var(--space-4);
}

.faq__item.active .faq__icon {
    transform: rotate(45deg);
}

.faq__answer {
    max-height: 0;
    overflow: hidden;
    background: var(--bg-secondary);
    transition: max-height 0.3s ease, padding 0.3s ease;
}

.faq__item.active .faq__answer {
    max-height: 300px;
    padding: var(--space-5) var(--space-6);
}

.faq__answer p {
    color: var(--text-secondary);
    line-height: 1.7;
    margin: 0;
    font-size: var(--font-size-md);
}

/* Footer */
.footer {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    padding: var(--space-16) 0 var(--space-8);
}

.footer__container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-4);
}

.footer__content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: var(--space-16);
    margin-bottom: var(--space-12);
}

.footer__logo {
    font-size: var(--font-size-2xl);
    font-weight: 800;
    margin-bottom: var(--space-4);
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.footer__description {
    color: var(--text-secondary);
    line-height: 1.6;
}

.footer__nav {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: var(--space-8);
}

.footer__title {
    font-size: var(--font-size-base);
    font-weight: 600;
    margin-bottom: var(--space-4);
    color: var(--text-primary);
}

.footer__links {
    list-style: none;
}

.footer__links li {
    margin-bottom: var(--space-2);
}

.footer__links a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: color 0.3s ease;
}

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

.footer__bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: var(--space-8);
    border-top: 1px solid var(--border-color);
    flex-wrap: wrap;
    gap: var(--space-4);
}

.footer__copyright {
    color: var(--text-secondary);
}

.footer__legal {
    display: flex;
    gap: var(--space-6);
}

.footer__legal a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: color 0.3s ease;
}

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

/* Back to Top Button */
.back-to-top {
    position: fixed;
    bottom: var(--space-8);
    right: var(--space-8);
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    border: none;
    border-radius: 50%;
    color: white;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    z-index: 9999;
    box-shadow: var(--shadow-lg);
}

.back-to-top.show {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl);
}

.back-to-top:active {
    transform: translateY(0);
}

/* Responsive Design */
@media (max-width: 1024px) {
    .hero__container {
        grid-template-columns: 1fr;
        gap: var(--space-12);
        text-align: center;
    }
    
    .hero__title {
        font-size: var(--font-size-4xl);
    }
    
    .features__grid {
        grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    }
    
    .workflow {
        flex-direction: column;
        align-items: center;
    }
    
    .workflow__connector {
        width: 60px;
        height: 2px;
        margin: var(--space-6) 0;
    }
    
    .about__grid {
        grid-template-columns: 1fr;
        gap: var(--space-12);
    }
    
    .about__stats {
        position: static;
    }
    
    .stats-grid {
        grid-template-columns: 1fr 1fr;
    }
    
    .faq__grid {
        grid-template-columns: 1fr;
        gap: var(--space-6);
    }
    
    .faq__category {
        padding: var(--space-6);
    }
    
    .video-section__title {
        font-size: var(--font-size-3xl);
    }
    
    .video-section__subtitle {
        font-size: var(--font-size-lg);
    }
    
    .video-wrapper {
        max-width: 100%;
        margin: 0 var(--space-4);
    }
}

@media (max-width: 768px) {
    .nav__menu {
        position: fixed;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--bg-primary);
        flex-direction: column;
        padding: var(--space-8) var(--space-4);
        border-top: 1px solid var(--border-color);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: all 0.3s ease;
        z-index: 999;
    }
    
    .nav__menu--active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }
    
    .nav__toggle {
        display: flex;
    }
    
    .hero {
        min-height: 80vh;
        padding-top: 80px;
    }
    
    .hero__container {
        padding: var(--space-20) var(--space-4);
        grid-template-columns: 1fr;
        text-align: center;
        gap: var(--space-12);
    }
    
    .hero__title {
        font-size: var(--font-size-3xl);
        line-height: 1.2;
        margin-bottom: var(--space-8);
    }
    
    .hero__subtitle {
        font-size: var(--font-size-lg);
    }
    
    .hero__actions {
        justify-content: center;
    }
    
    .hero__features {
        justify-content: center;
    }
    
    .features__grid {
        grid-template-columns: 1fr;
    }
    
    .footer__content {
        grid-template-columns: 1fr;
        gap: var(--space-8);
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
        gap: var(--space-4);
    }
    
    .footer__bottom {
        flex-direction: column;
        text-align: center;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
        gap: var(--space-4);
    }
    
    .faq__grid {
        grid-template-columns: 1fr;
        gap: var(--space-4);
    }
    
    .faq__category {
        padding: var(--space-5);
    }
    
    .faq__title {
        font-size: var(--font-size-3xl);
    }
    
    .video-section {
        padding: var(--space-16) 0;
    }
    
    .video-section__header {
        margin-bottom: var(--space-12);
    }
    
    .video-section__title {
        font-size: var(--font-size-2xl);
    }
    
    .video-section__subtitle {
        font-size: var(--font-size-base);
        max-width: 100%;
        padding: 0 var(--space-4);
    }
    
    .video-wrapper {
        margin: 0;
        border-radius: var(--radius-lg);
    }
    
    .faq__subtitle {
        font-size: var(--font-size-base);
    }
    
    .faq__question {
        font-size: var(--font-size-sm);
        padding: var(--space-4) var(--space-5);
    }
    
    .faq__item.active .faq__answer {
        padding: var(--space-4) var(--space-5);
    }
    
    .back-to-top {
        bottom: var(--space-6);
        right: var(--space-6);
        width: 45px;
        height: 45px;
    }
    
    /* 确保按钮在小屏幕上堆叠 */
    .about__cta-buttons {
        flex-direction: column;
        gap: var(--space-3);
    }
    
    /* Hero Chat Mobile Styles */
    .hero__container {
        gap: var(--space-8);
        padding: var(--space-12) var(--space-4);
    }
    
    .chat-widget__header {
        padding: var(--space-4);
    }
    
    .chat-widget__title {
        font-size: var(--font-size-lg);
    }
    
    .chat-widget__messages {
        height: 200px;
        padding: var(--space-3);
    }
    
    .chat-input {
        padding: var(--space-2);
    }
    
    .chat-input__send {
        width: 36px;
        height: 36px;
        padding: var(--space-2);
    }
    
    .chat-input__send svg {
        width: 16px;
        height: 16px;
    }
}

@media (max-width: 480px) {
    :root {
        --space-4: 0.75rem;
        --space-8: 1.5rem;
        --space-12: 2rem;
        --space-16: 2.5rem;
        --space-20: 3rem;
        --space-24: 4rem;
    }
    
    .hero {
        padding-top: 90px;
    }
    
    .hero__container {
        padding: var(--space-16) var(--space-4);
    }
    
    .hero__title {
        font-size: var(--font-size-2xl);
        line-height: 1.3;
        margin-bottom: var(--space-6);
    }
    
    .hero__features {
        justify-content: center;
    }
    
    .feature {
        padding: var(--space-6);
    }
    
    .features__title,
    .how-it-works__title {
        font-size: var(--font-size-3xl);
    }
    
    .btn {
        padding: var(--space-3) var(--space-5);
        font-size: var(--font-size-sm);
    }
}

/* Performance optimizations */

/* Accessibility improvements */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}

/* Focus styles for accessibility */
.btn:focus,
.nav__link:focus,
.footer__links a:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* Language Selector Styles */
.language-selector {
    position: relative;
    display: inline-block;
    margin-left: var(--space-4);
}

.language-selector__button {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-2) var(--space-4);
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-size: var(--font-size-sm);
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    white-space: nowrap;
}

.language-selector__button:hover {
    background: var(--bg-tertiary);
    border-color: var(--primary-color);
}

.language-selector__button:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

.language-selector__icon {
    font-size: var(--font-size-base);
}

.language-selector__text {
    font-weight: 600;
    color: var(--text-primary);
}

.language-selector__arrow {
    font-size: var(--font-size-xs);
    color: var(--text-secondary);
    transition: transform 0.2s ease;
}

.language-selector__button[aria-expanded="true"] .language-selector__arrow {
    transform: rotate(180deg);
}

.language-selector__dropdown {
    position: absolute;
    top: 100%;
    right: 0;
    min-width: 160px;
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all 0.2s ease;
    margin-top: var(--space-2);
}

.language-selector__dropdown.active {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.language-selector__option {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    width: 100%;
    padding: var(--space-3) var(--space-4);
    background: transparent;
    border: none;
    color: var(--text-primary);
    font-size: var(--font-size-sm);
    cursor: pointer;
    transition: all 0.2s ease;
    text-align: left;
}

.language-selector__option:hover {
    background: var(--bg-secondary);
}

.language-selector__option:focus {
    background: var(--bg-secondary);
    outline: none;
}

.language-selector__option:first-child {
    border-radius: var(--radius-md) var(--radius-md) 0 0;
}

.language-selector__option:last-child {
    border-radius: 0 0 var(--radius-md) var(--radius-md);
}

.language-selector__flag {
    font-size: var(--font-size-base);
    width: 20px;
    display: inline-block;
}

.language-selector__name {
    font-weight: 500;
    color: var(--text-primary);
}

/* Mobile styles for language selector */
@media (max-width: 768px) {
    .language-selector {
        margin-left: var(--space-2);
        margin-right: var(--space-2);
    }
    
    .language-selector__button {
        padding: var(--space-2) var(--space-3);
        font-size: var(--font-size-xs);
    }
    
    .language-selector__dropdown {
        min-width: 140px;
        right: 0;
    }
    
    .language-selector__option {
        padding: var(--space-2) var(--space-3);
        font-size: var(--font-size-xs);
    }
    
    .language-selector__flag {
        width: 18px;
        font-size: var(--font-size-sm);
    }
    
    /* 确保语言选择器在移动端菜单中正确显示 */
    .nav__menu--active .language-selector {
        order: -1;
        margin: 0 0 var(--space-4) 0;
        width: 100%;
    }
    
    .nav__menu--active .language-selector__button {
        width: 100%;
        justify-content: center;
    }
    
    .nav__menu--active .language-selector__dropdown {
        position: static;
        opacity: 1;
        visibility: visible;
        transform: none;
        margin-top: var(--space-2);
        width: 100%;
    }
}

}

/* Chat Widget Styles */
.chat-widget {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    overflow: hidden;
    width: 100%;
    max-width: 700px;
    margin: 0 auto;
    transition: all 0.3s ease;
}

.chat-widget:hover {
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    transform: translateY(-2px);
}

.chat-widget__header {
    padding: var(--space-6);
    background: linear-gradient(135deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
    border-bottom: 1px solid var(--border-color);
    text-align: center;
}

.chat-widget__title {
    font-size: var(--font-size-xl);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--space-2);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-3);
}

.chat-widget__icon {
    font-size: var(--font-size-2xl);
    animation: bounce 2s infinite;
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% {
        transform: translateY(0);
    }
    40% {
        transform: translateY(-5px);
    }
    60% {
        transform: translateY(-3px);
    }
}

.chat-widget__subtitle {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
    line-height: 1.5;
}

.chat-widget__messages {
    height: 300px;
    overflow-y: auto;
    padding: var(--space-4);
    background: var(--bg-primary);
    display: flex;
    flex-direction: column;
    gap: var(--space-4);
}

.chat-widget__messages::-webkit-scrollbar {
    width: 6px;
}

.chat-widget__messages::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

.chat-widget__messages::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 3px;
}

.chat-widget__messages::-webkit-scrollbar-thumb:hover {
    background: var(--primary-color);
}

.chat-message {
    display: flex;
    gap: var(--space-3);
    align-items: flex-start;
    max-width: 85%;
    animation: messageSlideIn 0.3s ease;
}

@keyframes messageSlideIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.chat-message--user {
    flex-direction: row-reverse;
    align-self: flex-end;
}

.chat-message--assistant {
    align-self: flex-start;
}

.chat-message__avatar {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--font-size-sm);
    flex-shrink: 0;
}

.chat-message--assistant .chat-message__avatar {
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    color: white;
}

.chat-message--user .chat-message__avatar {
    background: var(--bg-secondary);
    border: 2px solid var(--border-color);
    color: var(--text-secondary);
}

.chat-message__avatar-icon {
    font-size: var(--font-size-base);
}

.chat-message__content {
    flex: 1;
    min-width: 0;
}

.chat-message__text {
    padding: var(--space-3) var(--space-4);
    border-radius: var(--radius-lg);
    font-size: var(--font-size-base);
    line-height: 1.5;
    word-wrap: break-word;
}

.chat-message--assistant .chat-message__text {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg) var(--radius-lg) var(--radius-lg) var(--radius-sm);
}

.chat-message--user .chat-message__text {
    background: linear-gradient(135deg, var(--primary-color), var(--hover-color));
    color: white;
    border-radius: var(--radius-lg) var(--radius-lg) var(--radius-sm) var(--radius-lg);
}

.chat-widget__input-area {
    padding: var(--space-4);
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
}

.chat-input {
    display: flex;
    gap: var(--space-2);
    align-items: flex-end;
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.08);
    border-radius: 24px;
    padding: 8px 16px;
    transition: all 0.3s ease;
    backdrop-filter: blur(10px);
}

.chat-input:focus-within {
    border-color: rgba(255, 107, 53, 0.4);
    box-shadow: 0 0 20px rgba(255, 107, 53, 0.15);
    background: rgba(255, 255, 255, 0.05);
}

.chat-input__field {
    flex: 1;
    background: transparent;
    border: none;
    color: var(--text-primary);
    font-size: var(--font-size-base);
    line-height: 1.5;
    resize: none;
    max-height: 120px;
    min-height: 24px;
    font-family: inherit;
    padding: 8px 0;
}

.chat-input__field:focus {
    outline: none;
}

.chat-input__field::placeholder {
    color: rgba(148, 163, 184, 0.7);
    font-style: italic;
}

.chat-input__send {
    background: linear-gradient(135deg, var(--primary-color), var(--hover-color));
    border: none;
    border-radius: 20px;
    color: white;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0;
    transition: all 0.3s ease;
    flex-shrink: 0;
    width: 36px;
    height: 36px;
    box-shadow: 0 2px 8px rgba(255, 107, 53, 0.3);
}

.chat-input__send:hover:not(:disabled) {
    transform: translateY(-1px);
    box-shadow: 0 4px 16px rgba(255, 107, 53, 0.4);
    scale: 1.05;
}

.chat-input__send:disabled {
    opacity: 0.4;
    cursor: not-allowed;
    transform: none;
    scale: 1;
}

.chat-input__send:active {
    transform: translateY(0);
    scale: 0.98;
}

.chat-widget__footer {
    padding-top: var(--space-3);
    text-align: center;
}

.chat-widget__status {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
}

.chat-widget__status span {
    color: var(--primary-color);
    font-weight: 600;
}

/* Loading animation for messages */
.chat-message--loading .chat-message__text {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    padding: var(--space-4);
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

.typing-indicator {
    display: flex;
    gap: var(--space-1);
}

.typing-dot {
    width: 8px;
    height: 8px;
    background: var(--text-secondary);
    border-radius: 50%;
    animation: typing 1.4s infinite ease-in-out;
}

.typing-dot:nth-child(1) { animation-delay: -0.32s; }
.typing-dot:nth-child(2) { animation-delay: -0.16s; }

@keyframes typing {
    0%, 80%, 100% {
        transform: scale(0.8);
        opacity: 0.5;
    }
    40% {
        transform: scale(1);
        opacity: 1;
    }
}

/* Trial exhausted state */
.chat-widget--trial-exhausted .chat-input {
    opacity: 0.5;
    pointer-events: none;
}

.chat-widget--trial-exhausted .chat-widget__status {
    color: var(--primary-color);
}

/* Error message styles */
.chat-message--error .chat-message__text {
    background: rgba(239, 68, 68, 0.1);
    border-color: rgba(239, 68, 68, 0.3);
    color: #ef4444;
}

/* Print styles */
@media print {
    .header,
    .footer,
    .hero__actions,
    .nav__toggle,
    .language-selector {
        display: none;
    }
    
    .hero,
    .features,
    .how-it-works {
        background: white;
    }
    
    .chat-widget {
        display: none;
    }
}

/* Responsive Design for Chat Widget */
@media (max-width: 1024px) {
    .hero__container {
        gap: var(--space-10);
        padding: var(--space-16) var(--space-4);
    }
    
    .hero__title {
        font-size: var(--font-size-4xl);
    }
    
    .chat-widget {
        max-width: 100%;
    }
    
    .chat-widget__messages {
        height: 250px;
    }
    
    .features__grid {
        grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    }
    
    .workflow {
        flex-direction: column;
        align-items: center;
    }
    
    .workflow__connector {
        width: 60px;
        height: 2px;
        margin: var(--space-6) 0;
    }
    
    .about__grid {
        grid-template-columns: 1fr;
        gap: var(--space-12);
    }
    
    .about__stats {
        position: static;
    }
    
    .stats-grid {
        grid-template-columns: 1fr 1fr;
    }
    
    .faq__grid {
        grid-template-columns: 1fr;
        gap: var(--space-6);
    }
    
    .faq__category {
        padding: var(--space-6);
    }
    
    .video-section__title {
        font-size: var(--font-size-3xl);
    }
    
    .video-section__subtitle {
        font-size: var(--font-size-lg);
    }
    
    .video-wrapper {
        max-width: 100%;
        margin: 0 var(--space-4);
    }
}
}

/* Code Block Styles */
.code-block {
    margin: var(--space-4) 0;
    background: rgba(0, 0, 0, 0.3);
    border-radius: var(--radius-lg);
    border: 1px solid rgba(255, 255, 255, 0.1);
    overflow: hidden;
    font-family: 'Courier New', Consolas, 'Liberation Mono', Menlo, monospace;
}

.code-block__header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--space-3) var(--space-4);
    background: rgba(255, 255, 255, 0.05);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.code-block__language {
    font-size: var(--font-size-sm);
    color: var(--primary-color);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.code-block__copy {
    background: transparent;
    border: 1px solid rgba(255, 255, 255, 0.2);
    color: var(--text-secondary);
    border-radius: var(--radius-sm);
    padding: var(--space-1) var(--space-2);
    cursor: pointer;
    font-size: var(--font-size-sm);
    transition: all 0.2s ease;
}

.code-block__copy:hover {
    background: rgba(255, 255, 255, 0.1);
    color: var(--text-primary);
    border-color: var(--primary-color);
}

.code-block__content {
    margin: 0;
    padding: var(--space-4);
    background: transparent;
    color: #e2e8f0;
    font-size: var(--font-size-sm);
    line-height: 1.6;
    overflow-x: auto;
}

.code-block__content code {
    background: transparent;
    padding: 0;
    color: inherit;
    font-family: inherit;
    font-size: inherit;
}

/* Syntax highlighting colors */
.language-javascript .code-block__content,
.language-js .code-block__content {
    color: #f8f8f2;
}

.language-python .code-block__content {
    color: #f8f8f2;
}

/* Inline code */
.inline-code {
    background: rgba(255, 107, 53, 0.1);
    color: var(--primary-color);
    padding: 2px 6px;
    border-radius: var(--radius-sm);
    font-family: 'Courier New', Consolas, 'Liberation Mono', Menlo, monospace;
    font-size: 0.9em;
    border: 1px solid rgba(255, 107, 53, 0.2);
}

/* Text formatting */
.chat-message__text strong {
    color: var(--text-primary);
    font-weight: 700;
}

.chat-message__text em {
    color: var(--primary-color);
    font-style: italic;
}

/* Mobile code block adjustments */
@media (max-width: 768px) {
    .code-block {
        margin: var(--space-3) 0;
        border-radius: var(--radius-md);
    }
    
    .code-block__header {
        padding: var(--space-2) var(--space-3);
    }
    
    .code-block__content {
        padding: var(--space-3);
        font-size: var(--font-size-xs);
    }
    
    .code-block__copy {
        padding: 2px var(--space-1);
        font-size: 10px;
    }
}