/* ====================
   CSS Variables & Reset
   ==================== */
:root {
    /* 品牌色 - 科技蓝/紫调 */
    --primary-color: #00f2ff;
    --secondary-color: #7000ff;
    --accent-color: #00dbde;
    
    /* 深色模式背景 */
    --bg-dark: #0a0e17;
    --bg-card: #151b2b;
    --bg-card-hover: #1e2538;
    
    /* 文字颜色 */
    --text-main: #ffffff;
    --text-secondary: #a0aec0;
    --text-muted: #718096;
    
    /* 布局尺寸 */
    --container-width: 1200px;
    --header-height: 80px;
    
    /* 动效 */
    --transition-speed: 0.3s;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--bg-dark);
    color: var(--text-main);
    line-height: 1.6;
    overflow-x: hidden;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

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

ul {
    list-style: none;
}

img {
    max-width: 100%;
    display: block;
}

/* ====================
   Utilities
   ==================== */
.container {
    width: 90%;
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 20px;
}

.section-padding {
    padding: 100px 0;
}

.text-gradient {
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.btn {
    display: inline-block;
    padding: 12px 30px;
    border-radius: 50px;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-speed) ease;
    text-align: center;
    border: none;
    font-size: 1rem;
}

.btn-primary {
    background: linear-gradient(90deg, var(--secondary-color), var(--primary-color));
    color: white;
    box-shadow: 0 4px 15px rgba(0, 242, 255, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(0, 242, 255, 0.5);
}

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

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

.section-title {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 1rem;
    font-weight: 700;
}

.section-subtitle {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 4rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

/* ====================
   Header & Navigation
   ==================== */
header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    transition: background-color var(--transition-speed), padding var(--transition-speed);
    padding: 20px 0;
}

header.scrolled {
    background-color: rgba(10, 14, 23, 0.95);
    backdrop-filter: blur(10px);
    padding: 15px 0;
    box-shadow: 0 4px 20px rgba(0,0,0,0.3);
}

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

.logo {
    font-size: 1.8rem;
    font-weight: 800;
    letter-spacing: 1px;
    color: white;
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo span {
    color: var(--primary-color);
}

.nav-menu {
    display: flex;
    gap: 30px;
}

.nav-link {
    font-size: 1rem;
    color: var(--text-secondary);
    position: relative;
    padding: 5px 0;
}

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

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

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

.mobile-menu-btn {
    display: none;
    color: white;
    font-size: 1.5rem;
    cursor: pointer;
}

/* ====================
   Page Header (Sub-pages)
   ==================== */
.page-header {
    height: 400px;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    position: relative;
    background-size: cover;
    background-position: center;
    margin-top: 0;
}

.page-header-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(to bottom, rgba(10,14,23,0.8), var(--bg-dark));
    z-index: 1;
}

.page-header-content {
    position: relative;
    z-index: 2;
    padding-top: 60px;
}

.page-header h1 {
    font-size: 3rem;
    margin-bottom: 15px;
}

.page-header p {
    color: var(--text-secondary);
    font-size: 1.2rem;
    max-width: 600px;
    margin: 0 auto;
}

/* ====================
   Hero Section (Home)
   ==================== */
.hero {
    height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    background-image: url('../images/hero-bg.jpg');
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
}

.hero-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, rgba(10,14,23,0.95) 0%, rgba(10,14,23,0.7) 100%);
    z-index: 1;
}

.hero-content {
    position: relative;
    z-index: 2;
    max-width: 800px;
}

.hero h1 {
    font-size: 4rem;
    line-height: 1.2;
    margin-bottom: 20px;
    font-weight: 800;
}

.hero p {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 40px;
    max-width: 600px;
}

.hero-btns {
    display: flex;
    gap: 20px;
}

/* ====================
   Content Grid & Cards
   ==================== */
.services-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.card {
    background-color: var(--bg-card);
    padding: 40px 30px;
    border-radius: 20px;
    transition: var(--transition-speed);
    border: 1px solid rgba(255,255,255,0.05);
    position: relative;
    overflow: hidden;
    height: 100%;
}

.card:hover {
    transform: translateY(-10px);
    background-color: var(--bg-card-hover);
    border-color: var(--primary-color);
    box-shadow: 0 10px 30px rgba(0, 242, 255, 0.1);
}

.card-icon {
    font-size: 3rem;
    margin-bottom: 20px;
    color: var(--primary-color);
}

.card h3 {
    font-size: 1.5rem;
    margin-bottom: 15px;
}

.card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    margin-bottom: 20px;
}

.card-link {
    color: var(--primary-color);
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    gap: 5px;
}

.card-link:hover {
    gap: 10px;
}

/* ====================
   Detail Sections (Alternate Layout)
   ==================== */
.detail-section {
    padding: 80px 0;
    border-bottom: 1px solid rgba(255,255,255,0.05);
}

.detail-section:last-child {
    border-bottom: none;
}

.detail-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.detail-container.reverse {
    direction: rtl;
}

.detail-container.reverse .detail-content {
    direction: ltr;
}

.detail-image img {
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.5);
    transition: transform 0.5s;
}

.detail-image:hover img {
    transform: scale(1.02);
}

.detail-content h3 {
    font-size: 2rem;
    margin-bottom: 20px;
    color: var(--text-main);
}

.detail-content p {
    color: var(--text-secondary);
    margin-bottom: 20px;
    font-size: 1.05rem;
}

.feature-list {
    margin-top: 30px;
}

.feature-item {
    display: flex;
    align-items: flex-start;
    gap: 15px;
    margin-bottom: 15px;
}

.feature-icon {
    color: var(--primary-color);
    margin-top: 3px;
}

/* ====================
   Tech Advantages
   ==================== */
.tech-section {
    background: linear-gradient(to bottom, var(--bg-dark), #0f1420);
}

.tech-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 40px;
    align-items: center;
}

.tech-list {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 30px;
}

.tech-item {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.tech-item h4 {
    font-size: 1.2rem;
    color: var(--text-main);
    display: flex;
    align-items: center;
    gap: 10px;
}

.tech-item h4::before {
    content: '';
    display: block;
    width: 8px;
    height: 8px;
    background-color: var(--primary-color);
    border-radius: 50%;
    box-shadow: 0 0 10px var(--primary-color);
}

.tech-item p {
    color: var(--text-muted);
    font-size: 0.9rem;
    padding-left: 18px;
}

.tech-image {
    position: relative;
    border-radius: 20px;
    overflow: hidden;
    box-shadow: 0 20px 50px rgba(0,0,0,0.5);
}

.tech-image img {
    width: 100%;
    height: auto;
    transition: transform 0.5s;
}

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

/* ====================
   Use Cases / Solutions
   ==================== */
.scenarios-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
}

.scenario-card {
    position: relative;
    height: 300px;
    border-radius: 15px;
    overflow: hidden;
    cursor: pointer;
}

.scenario-bg {
    width: 100%;
    height: 100%;
    background-size: cover;
    background-position: center;
    transition: transform 0.5s;
}

.scenario-overlay {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(to top, rgba(0,0,0,0.9), transparent);
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    padding: 25px;
    transition: all 0.3s;
}

.scenario-card:hover .scenario-bg {
    transform: scale(1.1);
}

.scenario-card h3 {
    font-size: 1.4rem;
    margin-bottom: 10px;
}

.scenario-card p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    opacity: 0.8;
}

/* ====================
   About Us
   ==================== */
.about-wrapper {
    display: flex;
    gap: 50px;
    align-items: center;
}

.about-content {
    flex: 1;
}

.about-stats {
    display: flex;
    gap: 40px;
    margin-top: 30px;
}

.stat-item h2 {
    font-size: 2.5rem;
    color: var(--primary-color);
    font-weight: 800;
}

.stat-item p {
    font-size: 0.9rem;
    color: var(--text-muted);
}

.about-img {
    flex: 1;
    border-radius: 20px;
    overflow: hidden;
}

/* Timeline for About Page */
.timeline {
    position: relative;
    max-width: 800px;
    margin: 50px auto;
}

.timeline::after {
    content: '';
    position: absolute;
    width: 2px;
    background-color: rgba(255,255,255,0.1);
    top: 0;
    bottom: 0;
    left: 50%;
    margin-left: -1px;
}

.timeline-item {
    padding: 10px 40px;
    position: relative;
    background-color: inherit;
    width: 50%;
}

.timeline-item::after {
    content: '';
    position: absolute;
    width: 16px;
    height: 16px;
    right: -8px;
    background-color: var(--bg-dark);
    border: 2px solid var(--primary-color);
    top: 15px;
    border-radius: 50%;
    z-index: 1;
}

.timeline-left {
    left: 0;
}

.timeline-right {
    left: 50%;
}

.timeline-right::after {
    left: -8px;
}

.timeline-content {
    padding: 20px 30px;
    background-color: var(--bg-card);
    position: relative;
    border-radius: 10px;
    border: 1px solid rgba(255,255,255,0.05);
}

.timeline-content h3 {
    color: var(--primary-color);
    margin-bottom: 5px;
}

.timeline-content span {
    font-size: 0.85rem;
    color: var(--text-muted);
    display: block;
    margin-bottom: 10px;
}

/* ====================
   Contact
   ==================== */
.contact-container {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: 50px;
    background-color: var(--bg-card);
    padding: 50px;
    border-radius: 20px;
    border: 1px solid rgba(255,255,255,0.05);
}

.contact-info h3 {
    font-size: 1.8rem;
    margin-bottom: 20px;
}

.info-item {
    margin-bottom: 25px;
    display: flex;
    align-items: flex-start;
    gap: 15px;
}

.info-icon {
    color: var(--primary-color);
    font-size: 1.2rem;
    margin-top: 5px;
}

.info-text h4 {
    margin-bottom: 5px;
    color: var(--text-main);
}

.info-text p {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.contact-form {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.form-group input, .form-group textarea {
    width: 100%;
    padding: 15px;
    margin-bottom: 10px;
    background-color: rgba(255,255,255,0.03);
    border: 1px solid rgba(255,255,255,0.1);
    border-radius: 8px;
    color: white;
    font-family: inherit;
    transition: 0.3s;
}

.form-group input:focus, .form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    background-color: rgba(255,255,255,0.05);
}

.form-group textarea {
    height: 150px;
    resize: none;
}

/* ====================
   Footer
   ==================== */
footer {
    background-color: #05080f;
    padding: 60px 0 20px;
    border-top: 1px solid rgba(255,255,255,0.05);
    margin-top: auto;
}

.footer-content {
    display: grid;
    grid-template-columns: 1.5fr 1fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 40px;
}

.footer-brand h2 {
    font-size: 1.8rem;
    color: white;
    margin-bottom: 15px;
}

.footer-brand p {
    color: var(--text-muted);
    font-size: 0.9rem;
    max-width: 300px;
}

.footer-col h4 {
    color: white;
    margin-bottom: 20px;
    font-size: 1.1rem;
}

.footer-col ul li {
    margin-bottom: 10px;
}

.footer-col ul li a {
    color: var(--text-muted);
    font-size: 0.9rem;
}

.footer-col ul li a:hover {
    color: var(--primary-color);
}

.footer-bottom {
    text-align: center;
    padding-top: 20px;
    border-top: 1px solid rgba(255,255,255,0.05);
    color: var(--text-muted);
    font-size: 0.85rem;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

/* ====================
   Animations
   ==================== */
.fade-in-up {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.8s ease-out, transform 0.8s ease-out;
}

.fade-in-up.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ====================
   Responsive
   ==================== */
@media (max-width: 992px) {
    .hero h1 { font-size: 3rem; }
    .tech-grid { grid-template-columns: 1fr; }
    .tech-list { grid-template-columns: 1fr; }
    .about-wrapper { flex-direction: column; }
    .contact-container { grid-template-columns: 1fr; }
    .footer-content { grid-template-columns: 1fr 1fr; }
    .detail-container { grid-template-columns: 1fr !important; gap: 40px; }
    .detail-image { order: -1; }
    .timeline::after { left: 31px; }
    .timeline-item { width: 100%; padding-left: 70px; padding-right: 25px; }
    .timeline-item::after { left: 23px; }
    .timeline-right { left: 0; }
}

@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 0;
        right: -100%;
        width: 70%;
        height: 100vh;
        background-color: var(--bg-card);
        flex-direction: column;
        padding: 80px 30px;
        transition: 0.3s;
        box-shadow: -5px 0 15px rgba(0,0,0,0.5);
    }

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

    .mobile-menu-btn {
        display: block;
        z-index: 1001;
    }

    .hero h1 { font-size: 2.5rem; }
    .hero-btns { flex-direction: column; }
    .footer-content { grid-template-columns: 1fr; }
    .page-header h1 { font-size: 2.2rem; }
}