/* ========================================
   定神人工智能网络公司 - 维度分层风格
   3D与深度设计系统
   ======================================== */

/* CSS Variables - Design System */
:root {
    /* Colors */
    --bg: #F5F5F5;
    --surface: #FFFFFF;
    --layer-line: #E0E0E0;
    --ink: #17181C;
    --ink-soft: #4A4D57;
    --accent: #2563EB;
    --accent-deep: #1D4ED8;
    
    /* Elevation Shadows */
    --elevation-1: 0 1px 3px rgba(0,0,0,.1);
    --elevation-2: 0 4px 6px rgba(0,0,0,.1);
    --elevation-3: 0 10px 20px rgba(0,0,0,.1);
    --elevation-4: 0 20px 40px rgba(0,0,0,.12);
    
    /* Spacing */
    --space-xs: 4px;
    --space-sm: 8px;
    --space-md: 16px;
    --space-lg: 24px;
    --space-xl: 32px;
    --space-2xl: 48px;
    --space-3xl: 64px;
    --space-4xl: 96px;
    
    /* Border Radius - Core: 12px */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    
    /* Typography */
    --font-family: 'Space Grotesk', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    
    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-base: 0.25s ease;
    --transition-slow: 0.4s ease;
}

/* Reset & Base */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

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

body {
    font-family: var(--font-family);
    font-size: 16px;
    line-height: 1.6;
    color: var(--ink);
    background-color: var(--bg);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

@media (max-width: 768px) {
    .container {
        padding: 0 var(--space-md);
    }
}

/* ========================================
   Header & Navigation
   ======================================== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--layer-line);
    transition: all var(--transition-base);
}

.header.scrolled {
    box-shadow: var(--elevation-2);
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 72px;
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    text-decoration: none;
    color: var(--ink);
}

.logo-icon {
    flex-shrink: 0;
}

.logo-text {
    font-size: 18px;
    font-weight: 700;
    letter-spacing: -0.02em;
}

.nav {
    display: flex;
    align-items: center;
    gap: var(--space-xl);
}

.nav-link {
    font-size: 15px;
    font-weight: 500;
    color: var(--ink-soft);
    text-decoration: none;
    transition: color var(--transition-fast);
    position: relative;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent);
    transition: width var(--transition-base);
}

.nav-link:hover,
.nav-link.active {
    color: var(--ink);
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

.nav-link:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 4px;
    border-radius: 4px;
}

/* Mobile Menu Button */
.mobile-menu-btn {
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    width: 44px;
    height: 44px;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--space-sm);
}

.mobile-menu-btn span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--ink);
    margin: 3px 0;
    transition: all var(--transition-base);
    border-radius: 2px;
}

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

.mobile-menu-btn.active span:nth-child(2) {
    opacity: 0;
}

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

@media (max-width: 768px) {
    .mobile-menu-btn {
        display: flex;
    }
    
    .nav {
        position: fixed;
        top: 72px;
        left: 0;
        right: 0;
        flex-direction: column;
        background: var(--surface);
        padding: var(--space-lg);
        gap: var(--space-md);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: all var(--transition-base);
        box-shadow: var(--elevation-3);
    }
    
    .nav.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }
    
    .header .btn {
        display: none;
    }
}

/* ========================================
   Buttons
   ======================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-sm) var(--space-lg);
    font-family: var(--font-family);
    font-size: 15px;
    font-weight: 600;
    text-decoration: none;
    border-radius: var(--radius-md);
    border: none;
    cursor: pointer;
    transition: all var(--transition-base);
    min-height: 44px;
}

.btn:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

.btn-primary {
    background: var(--accent);
    color: white;
    box-shadow: var(--elevation-2), 0 0 0 0 rgba(37, 99, 235, 0.3);
}

.btn-primary:hover {
    background: var(--accent-deep);
    box-shadow: var(--elevation-3), 0 0 0 4px rgba(37, 99, 235, 0.2);
    transform: translateY(-2px);
}

.btn-primary:active {
    transform: translateY(0);
    box-shadow: var(--elevation-1);
}

.btn-secondary {
    background: transparent;
    color: var(--ink);
    border: 2px solid var(--layer-line);
}

.btn-secondary:hover {
    border-color: var(--accent);
    color: var(--accent);
    background: rgba(37, 99, 235, 0.05);
}

.btn-ghost {
    background: transparent;
    color: var(--ink-soft);
    padding: var(--space-sm) var(--space-md);
}

.btn-ghost:hover {
    color: var(--accent);
    background: rgba(37, 99, 235, 0.05);
}

.btn-lg {
    padding: var(--space-md) var(--space-xl);
    font-size: 16px;
    min-height: 48px;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none !important;
}

/* ========================================
   Hero Section
   ======================================== */
.hero {
    position: relative;
    padding: calc(72px + var(--space-4xl)) 0 var(--space-4xl);
    overflow: hidden;
    min-height: 90vh;
    display: flex;
    align-items: center;
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-3xl);
    align-items: center;
}

.hero-text {
    position: relative;
    z-index: 2;
}

.eyebrow {
    display: inline-block;
    font-size: 13px;
    font-weight: 600;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--accent);
    margin-bottom: var(--space-lg);
    padding: var(--space-xs) var(--space-md);
    background: rgba(37, 99, 235, 0.08);
    border-radius: var(--radius-sm);
}

.hero-title {
    font-size: clamp(2.5rem, 5vw, 4rem);
    font-weight: 900;
    line-height: 1.1;
    color: var(--ink);
    margin-bottom: var(--space-lg);
    letter-spacing: -0.02em;
}

.hero-subtitle {
    font-size: 18px;
    line-height: 1.6;
    color: var(--ink-soft);
    margin-bottom: var(--space-xl);
    max-width: 34em;
}

.hero-buttons {
    display: flex;
    gap: var(--space-md);
    flex-wrap: wrap;
}

/* Hero Visual - 3D Card Effect */
.hero-visual {
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 400px;
}

.hero-card {
    position: relative;
    width: 280px;
    height: 280px;
}

.card-3d {
    position: relative;
    transform-style: preserve-3d;
    perspective: 1000px;
}

.card-layer {
    position: absolute;
    border-radius: var(--radius-md);
    transition: transform var(--transition-slow);
}

.layer-1 {
    inset: 0;
    background: linear-gradient(135deg, rgba(37, 99, 235, 0.1), rgba(29, 78, 216, 0.05));
    box-shadow: var(--elevation-3);
    transform: translateZ(-30px) rotateX(5deg) rotateY(-5deg);
}

.layer-2 {
    inset: 20px;
    background: linear-gradient(135deg, rgba(37, 99, 235, 0.15), rgba(29, 78, 216, 0.1));
    box-shadow: var(--elevation-2);
    transform: translateZ(-15px) rotateX(3deg) rotateY(-3deg);
}

.layer-3 {
    inset: 40px;
    background: var(--surface);
    box-shadow: var(--elevation-4);
    display: flex;
    align-items: center;
    justify-content: center;
    transform: translateZ(0);
}

.hero-card:hover .layer-1 {
    transform: translateZ(-40px) rotateX(8deg) rotateY(-8deg);
}

.hero-card:hover .layer-2 {
    transform: translateZ(-20px) rotateX(5deg) rotateY(-5deg);
}

.hero-card:hover .layer-3 {
    transform: translateZ(10px);
}

/* Floating Elements */
.floating-element {
    position: absolute;
    border-radius: var(--radius-md);
    background: linear-gradient(135deg, var(--accent), var(--accent-deep));
    opacity: 0.6;
    animation: float 6s ease-in-out infinite;
}

.float-1 {
    width: 60px;
    height: 60px;
    top: 20%;
    left: 10%;
    animation-delay: 0s;
}

.float-2 {
    width: 40px;
    height: 40px;
    bottom: 25%;
    right: 15%;
    animation-delay: 2s;
    border-radius: 50%;
}

.float-3 {
    width: 30px;
    height: 30px;
    top: 60%;
    left: 20%;
    animation-delay: 4s;
}

@keyframes float {
    0%, 100% {
        transform: translateY(0) rotate(0deg);
    }
    50% {
        transform: translateY(-20px) rotate(5deg);
    }
}

/* Hero Background Decoration */
.hero-bg-decoration {
    position: absolute;
    inset: 0;
    pointer-events: none;
    overflow: hidden;
}

.deco-circle {
    position: absolute;
    border-radius: 50%;
    background: linear-gradient(135deg, rgba(37, 99, 235, 0.05), rgba(29, 78, 216, 0.02));
}

.deco-1 {
    width: 600px;
    height: 600px;
    top: -200px;
    right: -200px;
}

.deco-2 {
    width: 400px;
    height: 400px;
    bottom: -100px;
    left: -100px;
}

.deco-3 {
    width: 300px;
    height: 300px;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

@media (max-width: 768px) {
    .hero {
        padding: calc(72px + var(--space-2xl)) 0 var(--space-2xl);
        min-height: auto;
    }
    
    .hero-content {
        grid-template-columns: 1fr;
        gap: var(--space-2xl);
        text-align: center;
    }
    
    .hero-visual {
        min-height: 300px;
    }
    
    .hero-card {
        width: 220px;
        height: 220px;
    }
    
    .hero-buttons {
        justify-content: center;
    }
    
    .floating-element {
        display: none;
    }
}

/* ========================================
   Chips Section
   ======================================== */
.chips-section {
    padding: var(--space-xl) 0;
    background: var(--surface);
    border-top: 1px solid var(--layer-line);
    border-bottom: 1px solid var(--layer-line);
}

.chips-wrapper {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-sm);
    justify-content: center;
}

.chip {
    display: inline-flex;
    align-items: center;
    padding: var(--space-xs) var(--space-md);
    font-size: 13px;
    font-weight: 500;
    color: var(--ink-soft);
    background: var(--bg);
    border: 1px solid var(--layer-line);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
}

.chip:hover {
    border-color: var(--accent);
    color: var(--accent);
    background: rgba(37, 99, 235, 0.05);
    transform: translateY(-2px);
    box-shadow: var(--elevation-1);
}

/* ========================================
   Section Common Styles
   ======================================== */
.section {
    padding: var(--space-4xl) 0;
}

.section-header {
    text-align: center;
    margin-bottom: var(--space-3xl);
}

.section-eyebrow {
    display: inline-block;
    font-size: 13px;
    font-weight: 600;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--accent);
    margin-bottom: var(--space-md);
}

.section-title {
    font-size: clamp(1.75rem, 3vw, 2.5rem);
    font-weight: 800;
    line-height: 1.2;
    color: var(--ink);
    margin-bottom: var(--space-md);
}

.section-subtitle {
    font-size: 18px;
    color: var(--ink-soft);
    max-width: 34em;
    margin: 0 auto;
}

@media (max-width: 768px) {
    .section {
        padding: var(--space-2xl) 0;
    }
    
    .section-header {
        margin-bottom: var(--space-2xl);
    }
}

/* ========================================
   About Section
   ======================================== */
.about-section {
    background: var(--surface);
}

.about-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-3xl);
    align-items: center;
}

.about-text h3 {
    font-size: 24px;
    font-weight: 700;
    margin-bottom: var(--space-md);
    color: var(--ink);
}

.about-text p {
    font-size: 16px;
    line-height: 1.7;
    color: var(--ink-soft);
    margin-bottom: var(--space-md);
}

.about-stats {
    display: flex;
    gap: var(--space-xl);
    margin-top: var(--space-xl);
    padding-top: var(--space-xl);
    border-top: 1px solid var(--layer-line);
}

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

.stat-number {
    display: block;
    font-size: 32px;
    font-weight: 800;
    color: var(--accent);
    line-height: 1;
}

.stat-label {
    display: block;
    font-size: 14px;
    color: var(--ink-soft);
    margin-top: var(--space-xs);
}

.about-visual {
    display: flex;
    justify-content: center;
}

.about-card {
    width: 280px;
    height: 280px;
}

.about-card-inner {
    width: 100%;
    height: 100%;
    background: var(--surface);
    border-radius: var(--radius-md);
    box-shadow: var(--elevation-4);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: transform var(--transition-slow);
}

.about-card:hover .about-card-inner {
    transform: translateY(-8px) rotateX(5deg);
}

@media (max-width: 768px) {
    .about-content {
        grid-template-columns: 1fr;
        gap: var(--space-2xl);
    }
    
    .about-stats {
        justify-content: center;
    }
    
    .about-visual {
        order: -1;
    }
}

/* ========================================
   Services Section
   ======================================== */
.services-section {
    background: var(--bg);
}

.services-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-lg);
}

.service-card {
    background: var(--surface);
    border-radius: var(--radius-md);
    padding: var(--space-lg);
    box-shadow: var(--elevation-2);
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
}

.service-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--accent), var(--accent-deep));
    transform: scaleX(0);
    transform-origin: left;
    transition: transform var(--transition-base);
}

.service-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--elevation-4);
}

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

.service-icon {
    margin-bottom: var(--space-md);
}

.service-title {
    font-size: 18px;
    font-weight: 700;
    color: var(--ink);
    margin-bottom: var(--space-sm);
}

.service-desc {
    font-size: 15px;
    line-height: 1.6;
    color: var(--ink-soft);
    margin-bottom: var(--space-md);
}

.service-link {
    font-size: 14px;
    font-weight: 600;
    color: var(--accent);
    text-decoration: none;
    transition: color var(--transition-fast);
}

.service-link:hover {
    color: var(--accent-deep);
}

@media (max-width: 1024px) {
    .services-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 640px) {
    .services-grid {
        grid-template-columns: 1fr;
    }
}

/* ========================================
   Team Section
   ======================================== */
.team-section {
    background: var(--surface);
}

.team-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--space-lg);
}

.team-card {
    background: var(--bg);
    border-radius: var(--radius-md);
    padding: var(--space-lg);
    text-align: center;
    box-shadow: var(--elevation-1);
    transition: all var(--transition-base);
}

.team-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--elevation-3);
}

.team-avatar {
    margin-bottom: var(--space-md);
}

.team-name {
    font-size: 18px;
    font-weight: 700;
    color: var(--ink);
    margin-bottom: var(--space-xs);
}

.team-role {
    display: inline-block;
    font-size: 13px;
    font-weight: 600;
    color: var(--accent);
    margin-bottom: var(--space-md);
    padding: var(--space-xs) var(--space-sm);
    background: rgba(37, 99, 235, 0.08);
    border-radius: var(--radius-sm);
}

.team-bio {
    font-size: 14px;
    line-height: 1.6;
    color: var(--ink-soft);
}

@media (max-width: 1024px) {
    .team-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 640px) {
    .team-grid {
        grid-template-columns: 1fr;
    }
}

/* ========================================
   Contact Section
   ======================================== */
.contact-section {
    background: var(--bg);
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-3xl);
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: var(--space-lg);
}

.contact-item {
    display: flex;
    align-items: flex-start;
    gap: var(--space-md);
    padding: var(--space-lg);
    background: var(--surface);
    border-radius: var(--radius-md);
    box-shadow: var(--elevation-1);
    transition: all var(--transition-base);
}

.contact-item:hover {
    transform: translateX(8px);
    box-shadow: var(--elevation-2);
}

.contact-item svg {
    flex-shrink: 0;
}

.contact-item h4 {
    font-size: 16px;
    font-weight: 700;
    color: var(--ink);
    margin-bottom: var(--space-xs);
}

.contact-item p {
    font-size: 15px;
    color: var(--ink-soft);
}

/* Contact Form */
.contact-form {
    background: var(--surface);
    border-radius: var(--radius-md);
    padding: var(--space-xl);
    box-shadow: var(--elevation-2);
}

.form-group {
    margin-bottom: var(--space-lg);
}

.form-group label {
    display: block;
    font-size: 14px;
    font-weight: 600;
    color: var(--ink);
    margin-bottom: var(--space-sm);
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: var(--space-md);
    font-family: var(--font-family);
    font-size: 15px;
    color: var(--ink);
    background: var(--bg);
    border: 2px solid var(--layer-line);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
    min-height: 48px;
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--accent);
    background: var(--surface);
    box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.1);
}

.form-group input:focus-visible,
.form-group textarea:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: var(--ink-soft);
    opacity: 0.7;
}

.contact-form .btn {
    width: 100%;
}

@media (max-width: 768px) {
    .contact-content {
        grid-template-columns: 1fr;
        gap: var(--space-2xl);
    }
}

/* ========================================
   Footer
   ======================================== */
.footer {
    background: var(--ink);
    color: white;
    padding: var(--space-3xl) 0 var(--space-xl);
}

.footer-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: var(--space-3xl);
    margin-bottom: var(--space-2xl);
    padding-bottom: var(--space-2xl);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-brand .logo {
    color: white;
    margin-bottom: var(--space-md);
}

.footer-brand .logo-text {
    color: white;
}

.footer-desc {
    font-size: 15px;
    color: rgba(255, 255, 255, 0.7);
    max-width: 300px;
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-xl);
}

.footer-col h4 {
    font-size: 16px;
    font-weight: 700;
    margin-bottom: var(--space-md);
    color: white;
}

.footer-col a {
    display: block;
    font-size: 14px;
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    margin-bottom: var(--space-sm);
    transition: color var(--transition-fast);
}

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

.footer-bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--space-md);
}

.footer-bottom p {
    font-size: 14px;
    color: rgba(255, 255, 255, 0.6);
}

.footer-bottom a {
    color: rgba(255, 255, 255, 0.6);
    text-decoration: none;
    transition: color var(--transition-fast);
}

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

@media (max-width: 768px) {
    .footer-content {
        grid-template-columns: 1fr;
        gap: var(--space-2xl);
    }
    
    .footer-bottom {
        flex-direction: column;
        text-align: center;
    }
}

/* ========================================
   Utility Classes
   ======================================== */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* Focus visible for accessibility */
:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

/* Selection */
::selection {
    background: var(--accent);
    color: white;
}