/* ================================
   蔚来光科技 - 黑白简约风格样式表
   ================================ */

/* CSS Variables */
:root {
    --color-black: #000000;
    --color-white: #ffffff;
    --color-gray-100: #f5f5f5;
    --color-gray-200: #e5e5e5;
    --color-gray-300: #d4d4d4;
    --color-gray-400: #a3a3a3;
    --color-gray-500: #737373;
    --color-gray-600: #525252;
    --color-gray-700: #404040;
    --color-gray-800: #262626;
    --color-gray-900: #171717;
    
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
    
    --container-max: 1280px;
    --section-padding: 120px;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-primary);
    font-size: 16px;
    line-height: 1.6;
    color: var(--color-gray-800);
    background-color: var(--color-white);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

a {
    text-decoration: none;
    color: inherit;
    transition: var(--transition-fast);
}

img {
    max-width: 100%;
    height: auto;
    display: block;
    filter: grayscale(100%);
    transition: filter 0.5s ease;
}

img:hover {
    filter: grayscale(0%);
}

ul {
    list-style: none;
}

/* Container */
.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 40px;
}

/* ================================
   Navigation
   ================================ */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-gray-200);
    transition: var(--transition-normal);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 80px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 600;
    font-size: 1.2rem;
    color: var(--color-black);
}

.logo-icon {
    font-size: 1.5rem;
    color: var(--color-black);
}

.nav-menu {
    display: flex;
    gap: 40px;
}

.nav-menu a {
    font-size: 0.95rem;
    font-weight: 500;
    color: var(--color-gray-600);
    position: relative;
}

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

.nav-menu a:hover,
.nav-menu a.active {
    color: var(--color-black);
}

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

.hamburger {
    display: none;
    flex-direction: column;
    gap: 6px;
    cursor: pointer;
}

.hamburger span {
    width: 24px;
    height: 2px;
    background: var(--color-black);
    transition: var(--transition-normal);
}

/* ================================
   Hero Section
   ================================ */
.hero {
    height: 100vh;
    min-height: 700px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    background: var(--color-white);
    position: relative;
    padding-top: 80px;
}

.hero-content {
    max-width: 900px;
    padding: 0 40px;
}

.hero h1 {
    font-size: clamp(2.5rem, 6vw, 4.5rem);
    font-weight: 300;
    line-height: 1.2;
    color: var(--color-black);
    margin-bottom: 24px;
    letter-spacing: -0.02em;
}

.hero-subtitle {
    font-size: 1.1rem;
    color: var(--color-gray-500);
    margin-bottom: 40px;
    font-weight: 400;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 14px 32px;
    font-size: 0.95rem;
    font-weight: 500;
    border-radius: 0;
    cursor: pointer;
    transition: var(--transition-normal);
    border: 2px solid transparent;
}

.btn-primary {
    background: var(--color-black);
    color: var(--color-white);
    border-color: var(--color-black);
}

.btn-primary:hover {
    background: var(--color-gray-800);
    border-color: var(--color-gray-800);
}

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

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

.btn-full {
    width: 100%;
}

.hero-scroll {
    position: absolute;
    bottom: 60px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
    color: var(--color-gray-400);
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

.scroll-line {
    width: 1px;
    height: 60px;
    background: linear-gradient(to bottom, var(--color-gray-400), transparent);
    animation: scrollPulse 2s infinite;
}

@keyframes scrollPulse {
    0%, 100% { opacity: 0.3; transform: scaleY(0.5); }
    50% { opacity: 1; transform: scaleY(1); }
}

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

.section-header {
    text-align: center;
    margin-bottom: 80px;
}

.section-tag {
    display: inline-block;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.2em;
    color: var(--color-gray-400);
    margin-bottom: 20px;
}

.section-header h2 {
    font-size: clamp(1.8rem, 4vw, 2.8rem);
    font-weight: 300;
    color: var(--color-black);
    line-height: 1.3;
}

/* ================================
   About Section
   ================================ */
.about {
    background: var(--color-gray-100);
}

.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 80px;
    align-items: center;
}

.about-content p {
    font-size: 1.05rem;
    color: var(--color-gray-600);
    margin-bottom: 24px;
    line-height: 1.8;
}

.stats {
    display: flex;
    gap: 40px;
    margin-top: 48px;
    padding-top: 48px;
    border-top: 1px solid var(--color-gray-300);
}

.stat-item {
    display: flex;
    flex-direction: column;
}

.stat-number {
    font-size: 2.5rem;
    font-weight: 300;
    color: var(--color-black);
    line-height: 1;
}

.stat-label {
    font-size: 0.85rem;
    color: var(--color-gray-500);
    margin-top: 8px;
}

.about-image {
    position: relative;
}

.about-image img {
    width: 100%;
    height: 500px;
    object-fit: cover;
}

.about-image::before {
    content: '';
    position: absolute;
    top: 20px;
    left: 20px;
    right: -20px;
    bottom: -20px;
    border: 1px solid var(--color-gray-300);
    z-index: -1;
}

/* ================================
   Products Section
   ================================ */
.products {
    background: var(--color-white);
}

.product-category {
    margin-bottom: 100px;
}

.product-category:last-child {
    margin-bottom: 0;
}

.category-title {
    font-size: 1.3rem;
    font-weight: 500;
    color: var(--color-black);
    margin-bottom: 40px;
    padding-bottom: 16px;
    border-bottom: 1px solid var(--color-gray-200);
}

.product-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(480px, 1fr));
    gap: 40px;
}

.product-card {
    display: grid;
    grid-template-columns: 280px 1fr;
    gap: 32px;
    background: var(--color-gray-100);
    overflow: hidden;
    transition: var(--transition-normal);
}

.product-card:hover {
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.08);
}

.product-image {
    overflow: hidden;
    background: var(--color-white);
}

.product-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: var(--transition-slow);
}

.product-card:hover .product-image img {
    transform: scale(1.05);
}

.product-info {
    padding: 32px 32px 32px 0;
}

.product-info h4 {
    font-size: 1.3rem;
    font-weight: 500;
    color: var(--color-black);
    margin-bottom: 16px;
}

.product-info p {
    font-size: 0.95rem;
    color: var(--color-gray-600);
    margin-bottom: 20px;
    line-height: 1.7;
}

.product-features {
    margin-bottom: 24px;
}

.product-features li {
    font-size: 0.9rem;
    color: var(--color-gray-500);
    padding: 6px 0;
    padding-left: 16px;
    position: relative;
}

.product-features li::before {
    content: '—';
    position: absolute;
    left: 0;
    color: var(--color-gray-300);
}

.product-link {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--color-black);
    position: relative;
}

.product-link::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 100%;
    height: 1px;
    background: var(--color-black);
    transform: scaleX(0);
    transform-origin: right;
    transition: transform var(--transition-normal);
}

.product-link:hover::after {
    transform: scaleX(1);
    transform-origin: left;
}

/* ================================
   Applications Section
   ================================ */
.applications {
    background: var(--color-black);
    color: var(--color-white);
}

.applications .section-tag {
    color: var(--color-gray-500);
}

.applications .section-header h2 {
    color: var(--color-white);
}

.app-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2px;
    background: var(--color-gray-800);
}

.app-card {
    background: var(--color-black);
    padding: 48px;
    transition: var(--transition-normal);
}

.app-card:hover {
    background: var(--color-gray-900);
}

.app-icon {
    font-size: 1.5rem;
    margin-bottom: 24px;
    opacity: 0.5;
}

.app-card h3 {
    font-size: 1.2rem;
    font-weight: 500;
    color: var(--color-white);
    margin-bottom: 16px;
}

.app-card p {
    font-size: 0.95rem;
    color: var(--color-gray-400);
    line-height: 1.7;
}

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

.service-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 40px;
}

.service-item {
    padding: 40px;
    border: 1px solid var(--color-gray-200);
    transition: var(--transition-normal);
}

.service-item:hover {
    border-color: var(--color-black);
}

.service-number {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--color-gray-300);
    margin-bottom: 24px;
}

.service-item h3 {
    font-size: 1.2rem;
    font-weight: 500;
    color: var(--color-black);
    margin-bottom: 16px;
}

.service-item p {
    font-size: 0.95rem;
    color: var(--color-gray-600);
    line-height: 1.7;
}

/* ================================
   Contact Section
   ================================ */
.contact {
    background: var(--color-gray-100);
}

.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1.2fr;
    gap: 80px;
}

.contact-info h3 {
    font-size: 1.5rem;
    font-weight: 500;
    color: var(--color-black);
    margin-bottom: 40px;
}

.contact-item {
    margin-bottom: 32px;
}

.contact-label {
    display: block;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--color-gray-400);
    margin-bottom: 8px;
}

.contact-item p {
    font-size: 1rem;
    color: var(--color-gray-700);
}

.social-links {
    display: flex;
    gap: 16px;
    margin-top: 48px;
}

.social-link {
    padding: 10px 24px;
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--color-gray-600);
    border: 1px solid var(--color-gray-300);
    transition: var(--transition-normal);
}

.social-link:hover {
    background: var(--color-black);
    color: var(--color-white);
    border-color: var(--color-black);
}

.contact-form {
    background: var(--color-white);
    padding: 48px;
}

.form-group {
    margin-bottom: 24px;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 16px;
    font-size: 1rem;
    font-family: inherit;
    border: 1px solid var(--color-gray-200);
    background: transparent;
    color: var(--color-black);
    transition: var(--transition-normal);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--color-black);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: var(--color-gray-400);
}

/* ================================
   Footer
   ================================ */
.footer {
    background: var(--color-black);
    color: var(--color-white);
    padding: 80px 0 40px;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 60px;
    margin-bottom: 60px;
}

.footer-brand .logo {
    color: var(--color-white);
    margin-bottom: 24px;
}

.footer-brand p {
    font-size: 0.95rem;
    color: var(--color-gray-500);
    line-height: 1.7;
}

.footer-links h4 {
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--color-white);
    margin-bottom: 24px;
}

.footer-links li {
    margin-bottom: 12px;
}

.footer-links a {
    font-size: 0.95rem;
    color: var(--color-gray-500);
}

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

.footer-bottom {
    display: flex;
    justify-content: space-between;
    padding-top: 40px;
    border-top: 1px solid var(--color-gray-800);
}

.footer-bottom p {
    font-size: 0.85rem;
    color: var(--color-gray-500);
}

/* ================================
   Responsive Design
   ================================ */
@media (max-width: 1024px) {
    :root {
        --section-padding: 80px;
    }
    
    .about-grid {
        grid-template-columns: 1fr;
        gap: 60px;
    }
    
    .about-image {
        order: -1;
    }
    
    .about-image img {
        height: 400px;
    }
    
    .product-grid {
        grid-template-columns: 1fr;
    }
    
    .product-card {
        grid-template-columns: 240px 1fr;
    }
    
    .app-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .service-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .contact-grid {
        grid-template-columns: 1fr;
        gap: 60px;
    }
    
    .footer-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .container {
        padding: 0 24px;
    }
    
    .nav-menu {
        position: fixed;
        top: 80px;
        left: 0;
        right: 0;
        background: var(--color-white);
        flex-direction: column;
        padding: 40px;
        gap: 24px;
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: var(--transition-normal);
        border-bottom: 1px solid var(--color-gray-200);
    }
    
    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }
    
    .hamburger {
        display: flex;
    }
    
    .hero h1 {
        font-size: 2rem;
    }
    
    .hero-buttons {
        flex-direction: column;
    }
    
    .stats {
        flex-wrap: wrap;
        gap: 24px;
    }
    
    .stat-number {
        font-size: 2rem;
    }
    
    .product-card {
        grid-template-columns: 1fr;
    }
    
    .product-image {
        height: 240px;
    }
    
    .product-info {
        padding: 32px;
    }
    
    .app-grid {
        grid-template-columns: 1fr;
    }
    
    .service-grid {
        grid-template-columns: 1fr;
    }
    
    .footer-grid {
        grid-template-columns: 1fr;
        gap: 40px;
    }
    
    .footer-bottom {
        flex-direction: column;
        gap: 16px;
        text-align: center;
    }
}

/* ================================
   Animations
   ================================ */
@media (prefers-reduced-motion: no-preference) {
    .product-card,
    .app-card,
    .service-item {
        opacity: 0;
        transform: translateY(30px);
        animation: fadeInUp 0.6s ease forwards;
    }
    
    .product-card:nth-child(1) { animation-delay: 0.1s; }
    .product-card:nth-child(2) { animation-delay: 0.2s; }
    .app-card:nth-child(1) { animation-delay: 0.1s; }
    .app-card:nth-child(2) { animation-delay: 0.15s; }
    .app-card:nth-child(3) { animation-delay: 0.2s; }
    .app-card:nth-child(4) { animation-delay: 0.25s; }
    .app-card:nth-child(5) { animation-delay: 0.3s; }
    .app-card:nth-child(6) { animation-delay: 0.35s; }
    .service-item:nth-child(1) { animation-delay: 0.1s; }
    .service-item:nth-child(2) { animation-delay: 0.15s; }
    .service-item:nth-child(3) { animation-delay: 0.2s; }
    .service-item:nth-child(4) { animation-delay: 0.25s; }
}

@keyframes fadeInUp {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}