/* ================================================
   Beijing Kesier Technology Development Co., Ltd.
   Main Stylesheet
   ================================================ */

/* CSS Variables */
:root {
    --primary-color: #0a192f;
    --secondary-color: #172a45;
    --accent-color: #64ffda;
    --text-primary: #e6f1ff;
    --text-secondary: #8892b0;
    --white: #ffffff;
    --black: #000000;
    --gradient-start: #0a192f;
    --gradient-end: #020c1b;
    --card-bg: rgba(23, 42, 69, 0.7);
    --border-color: rgba(100, 255, 218, 0.1);
    --shadow: 0 10px 30px -10px rgba(2, 12, 27, 0.7);
    --transition: all 0.25s cubic-bezier(0.645, 0.045, 0.355, 1);
}

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

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--primary-color);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

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

ul, ol {
    list-style: none;
}

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

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 1rem;
}

h1 {
    font-size: clamp(2.5rem, 5vw, 4.5rem);
}

h2 {
    font-size: clamp(2rem, 4vw, 3rem);
    color: var(--accent-color);
}

h3 {
    font-size: clamp(1.5rem, 3vw, 2rem);
}

p {
    margin-bottom: 1rem;
    color: var(--text-secondary);
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    padding: 20px 0;
    transition: var(--transition);
    background: transparent;
}

.navbar.scrolled {
    background: rgba(10, 25, 47, 0.95);
    backdrop-filter: blur(10px);
    padding: 15px 0;
    box-shadow: var(--shadow);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 15px;
}

.logo svg {
    width: 50px;
    height: 50px;
}

.logo-text {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--accent-color);
}

.nav-links {
    display: flex;
    gap: 40px;
    align-items: center;
}

.nav-links a {
    color: var(--text-primary);
    font-size: 0.95rem;
    font-weight: 500;
    position: relative;
    padding: 5px 0;
}

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

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

.nav-links a:hover,
.nav-links a.active {
    color: var(--accent-color);
}

/* Mobile Menu */
.menu-toggle {
    display: none;
    flex-direction: column;
    gap: 6px;
    cursor: pointer;
    padding: 10px;
}

.menu-toggle span {
    width: 28px;
    height: 3px;
    background: var(--accent-color);
    border-radius: 3px;
    transition: var(--transition);
}

.menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(6px, 6px);
}

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

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

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
    padding: 100px 20px;
}

.hero-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, var(--gradient-start) 0%, var(--gradient-end) 100%);
}

.hero-bg::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><circle cx="50" cy="50" r="1" fill="%2364ffda" opacity="0.1"/></svg>');
    background-size: 50px 50px;
    animation: moveBackground 20s linear infinite;
}

@keyframes moveBackground {
    0% { transform: translate(0, 0); }
    100% { transform: translate(50px, 50px); }
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
    max-width: 900px;
}

.hero-subtitle {
    color: var(--accent-color);
    font-size: 1.1rem;
    letter-spacing: 3px;
    text-transform: uppercase;
    margin-bottom: 20px;
    opacity: 0;
    transform: translateY(20px);
    animation: fadeInUp 0.8s ease forwards 0.3s;
}

.hero-title {
    color: var(--text-primary);
    margin-bottom: 30px;
    opacity: 0;
    transform: translateY(20px);
    animation: fadeInUp 0.8s ease forwards 0.5s;
}

.hero-title .highlight {
    color: var(--accent-color);
}

.hero-description {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 40px;
    opacity: 0;
    transform: translateY(20px);
    animation: fadeInUp 0.8s ease forwards 0.7s;
}

.hero-buttons {
    display: flex;
    gap: 20px;
    justify-content: center;
    flex-wrap: wrap;
    opacity: 0;
    transform: translateY(20px);
    animation: fadeInUp 0.8s ease forwards 0.9s;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 16px 32px;
    font-size: 1rem;
    font-weight: 600;
    border-radius: 4px;
    cursor: pointer;
    transition: var(--transition);
    border: none;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.btn-primary {
    background: var(--accent-color);
    color: var(--primary-color);
}

.btn-primary:hover {
    background: #4fd9be;
    transform: translateY(-3px);
    box-shadow: 0 10px 30px rgba(100, 255, 218, 0.3);
}

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

.btn-secondary:hover {
    background: rgba(100, 255, 218, 0.1);
    transform: translateY(-3px);
}

/* Scroll Indicator */
.scroll-indicator {
    position: absolute;
    bottom: 40px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
    animation: bounce 2s infinite;
}

.scroll-indicator span {
    color: var(--text-secondary);
    font-size: 0.85rem;
    letter-spacing: 2px;
    text-transform: uppercase;
}

.scroll-indicator svg {
    width: 24px;
    height: 24px;
    stroke: var(--accent-color);
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% { transform: translateX(-50%) translateY(0); }
    40% { transform: translateX(-50%) translateY(-10px); }
    60% { transform: translateX(-50%) translateY(-5px); }
}

/* Sections */
.section {
    padding: 100px 0;
    position: relative;
}

.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-number {
    color: var(--accent-color);
    font-size: 0.9rem;
    letter-spacing: 3px;
    margin-bottom: 10px;
}

.section-title {
    margin-bottom: 20px;
}

.section-subtitle {
    max-width: 600px;
    margin: 0 auto;
    color: var(--text-secondary);
}

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

.about-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    margin-top: 50px;
}

.about-card {
    background: var(--card-bg);
    padding: 40px 30px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    transition: var(--transition);
    backdrop-filter: blur(10px);
}

.about-card:hover {
    transform: translateY(-10px);
    border-color: var(--accent-color);
    box-shadow: var(--shadow);
}

.about-card-icon {
    width: 60px;
    height: 60px;
    margin-bottom: 20px;
}

.about-card-icon svg {
    width: 100%;
    height: 100%;
    stroke: var(--accent-color);
}

.about-card h3 {
    color: var(--text-primary);
    margin-bottom: 15px;
}

.about-card p {
    font-size: 0.95rem;
}

/* Services Preview */
.services-preview {
    background: var(--primary-color);
}

.services-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.service-card {
    background: var(--card-bg);
    border-radius: 8px;
    overflow: hidden;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.service-card:hover {
    transform: translateY(-5px);
    border-color: var(--accent-color);
}

.service-image {
    height: 200px;
    background: linear-gradient(135deg, var(--secondary-color), var(--primary-color));
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
}

.service-image::before {
    content: '';
    position: absolute;
    width: 100%;
    height: 100%;
    background: linear-gradient(45deg, transparent 30%, rgba(100, 255, 218, 0.1) 50%, transparent 70%);
    transform: translateX(-100%);
    transition: 0.6s;
}

.service-card:hover .service-image::before {
    transform: translateX(100%);
}

.service-image svg {
    width: 80px;
    height: 80px;
    stroke: var(--accent-color);
    position: relative;
    z-index: 1;
}

.service-content {
    padding: 30px;
}

.service-content h3 {
    color: var(--text-primary);
    margin-bottom: 15px;
}

.service-content p {
    font-size: 0.95rem;
    margin-bottom: 20px;
}

.service-link {
    color: var(--accent-color);
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    gap: 8px;
}

.service-link svg {
    width: 16px;
    height: 16px;
    transition: var(--transition);
}

.service-link:hover svg {
    transform: translateX(5px);
}

/* App Showcase */
.app-showcase {
    background: var(--secondary-color);
    position: relative;
    overflow: hidden;
}

.app-showcase::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(circle at 20% 50%, rgba(100, 255, 218, 0.05) 0%, transparent 50%);
}

.app-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
    position: relative;
    z-index: 1;
}

.app-content h2 {
    margin-bottom: 30px;
}

.app-features {
    display: flex;
    flex-direction: column;
    gap: 20px;
    margin-top: 30px;
}

.app-feature {
    display: flex;
    align-items: flex-start;
    gap: 15px;
}

.app-feature-icon {
    width: 40px;
    height: 40px;
    min-width: 40px;
    background: rgba(100, 255, 218, 0.1);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.app-feature-icon svg {
    width: 20px;
    height: 20px;
    stroke: var(--accent-color);
}

.app-feature h4 {
    color: var(--text-primary);
    margin-bottom: 5px;
}

.app-feature p {
    font-size: 0.9rem;
    margin: 0;
}

.app-image {
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
}

.phone-mockup {
    width: 300px;
    height: 600px;
    background: linear-gradient(145deg, #1a1a2e, #16213e);
    border-radius: 40px;
    padding: 10px;
    box-shadow: 0 30px 60px rgba(0, 0, 0, 0.5);
    position: relative;
    animation: float 6s ease-in-out infinite;
}

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

.phone-screen {
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, var(--secondary-color), var(--primary-color));
    border-radius: 32px;
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

.phone-notch {
    width: 120px;
    height: 30px;
    background: #000;
    margin: 0 auto;
    border-radius: 0 0 20px 20px;
}

.phone-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 20px;
    padding: 20px;
}

.phone-content svg {
    width: 100px;
    height: 100px;
    stroke: var(--accent-color);
}

.phone-content p {
    color: var(--text-primary);
    font-size: 0.9rem;
    text-align: center;
}

/* Stats Section */
.stats-section {
    background: var(--primary-color);
    padding: 80px 0;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 30px;
}

.stat-item {
    text-align: center;
    padding: 30px;
}

.stat-number {
    font-size: 3.5rem;
    font-weight: 700;
    color: var(--accent-color);
    margin-bottom: 10px;
    line-height: 1;
}

.stat-label {
    color: var(--text-secondary);
    font-size: 1rem;
    text-transform: uppercase;
    letter-spacing: 2px;
}

/* CTA Section */
.cta-section {
    background: linear-gradient(135deg, var(--accent-color) 0%, #4fd9be 100%);
    padding: 100px 0;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.cta-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><circle cx="50" cy="50" r="2" fill="%230a192f" opacity="0.1"/></svg>');
    background-size: 30px 30px;
}

.cta-content {
    position: relative;
    z-index: 1;
}

.cta-content h2 {
    color: var(--primary-color);
    margin-bottom: 20px;
}

.cta-content p {
    color: var(--secondary-color);
    font-size: 1.2rem;
    max-width: 600px;
    margin: 0 auto 30px;
}

.cta-btn {
    background: var(--primary-color);
    color: var(--text-primary);
    padding: 18px 40px;
    font-size: 1rem;
}

.cta-btn:hover {
    background: var(--secondary-color);
    transform: translateY(-3px);
    box-shadow: 0 15px 40px rgba(10, 25, 47, 0.3);
}

/* Footer */
.footer {
    background: var(--gradient-end);
    padding: 80px 0 30px;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 60px;
}

.footer-brand p {
    margin-top: 20px;
    font-size: 0.95rem;
}

.footer-column h4 {
    color: var(--text-primary);
    margin-bottom: 20px;
    font-size: 1.1rem;
}

.footer-links {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.footer-links a {
    color: var(--text-secondary);
    font-size: 0.95rem;
    transition: var(--transition);
}

.footer-links a:hover {
    color: var(--accent-color);
    padding-left: 5px;
}

.footer-contact {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.footer-contact-item {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.footer-contact-item svg {
    width: 20px;
    height: 20px;
    stroke: var(--accent-color);
    min-width: 20px;
    margin-top: 2px;
}

.footer-contact-item a:hover {
    color: var(--accent-color);
}

.footer-bottom {
    border-top: 1px solid rgba(100, 255, 218, 0.1);
    padding-top: 30px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 20px;
}

.footer-bottom p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin: 0;
}

.footer-legal {
    display: flex;
    gap: 30px;
}

.footer-legal a {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.footer-legal a:hover {
    color: var(--accent-color);
}

.social-links {
    display: flex;
    gap: 15px;
    margin-top: 20px;
}

.social-link {
    width: 40px;
    height: 40px;
    background: rgba(100, 255, 218, 0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

.social-link:hover {
    background: var(--accent-color);
}

.social-link svg {
    width: 20px;
    height: 20px;
    stroke: var(--accent-color);
    transition: var(--transition);
}

.social-link:hover svg {
    stroke: var(--primary-color);
}

/* Page Header */
.page-header {
    padding: 180px 0 100px;
    background: linear-gradient(135deg, var(--gradient-start) 0%, var(--gradient-end) 100%);
    position: relative;
    overflow: hidden;
}

.page-header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><circle cx="50" cy="50" r="1" fill="%2364ffda" opacity="0.05"/></svg>');
    background-size: 40px 40px;
}

.page-header-content {
    position: relative;
    z-index: 1;
    text-align: center;
}

.page-header h1 {
    margin-bottom: 20px;
}

.page-header p {
    max-width: 600px;
    margin: 0 auto;
}

/* Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes slideInLeft {
    from {
        opacity: 0;
        transform: translateX(-50px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes slideInRight {
    from {
        opacity: 0;
        transform: translateX(50px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes scaleIn {
    from {
        opacity: 0;
        transform: scale(0.9);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

@keyframes rotateIn {
    from {
        opacity: 0;
        transform: rotate(-10deg) scale(0.9);
    }
    to {
        opacity: 1;
        transform: rotate(0) scale(1);
    }
}

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
        opacity: 1;
    }
    50% {
        transform: scale(1.05);
        opacity: 0.8;
    }
}

@keyframes shimmer {
    0% {
        background-position: -200% 0;
    }
    100% {
        background-position: 200% 0;
    }
}

.animate-on-scroll {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.8s ease;
}

.animate-on-scroll.visible {
    opacity: 1;
    transform: translateY(0);
}

.animate-delay-1 { transition-delay: 0.1s; }
.animate-delay-2 { transition-delay: 0.2s; }
.animate-delay-3 { transition-delay: 0.3s; }
.animate-delay-4 { transition-delay: 0.4s; }
.animate-delay-5 { transition-delay: 0.5s; }

/* Form Styles */
.form-group {
    margin-bottom: 25px;
}

.form-label {
    display: block;
    color: var(--text-primary);
    margin-bottom: 8px;
    font-weight: 500;
}

.form-input,
.form-textarea,
.form-select {
    width: 100%;
    padding: 15px 20px;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    color: var(--text-primary);
    font-size: 1rem;
    transition: var(--transition);
}

.form-input:focus,
.form-textarea:focus,
.form-select:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(100, 255, 218, 0.1);
}

.form-textarea {
    min-height: 150px;
    resize: vertical;
}

.form-input::placeholder,
.form-textarea::placeholder {
    color: var(--text-secondary);
}

/* Responsive Design */
@media (max-width: 1024px) {
    .footer-grid {
        grid-template-columns: 1fr 1fr;
    }
    
    .app-grid {
        grid-template-columns: 1fr;
        gap: 40px;
    }
    
    .app-image {
        order: -1;
    }
    
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .nav-links {
        position: fixed;
        top: 0;
        right: -100%;
        width: 70%;
        max-width: 300px;
        height: 100vh;
        background: var(--secondary-color);
        flex-direction: column;
        justify-content: center;
        gap: 30px;
        transition: var(--transition);
        box-shadow: var(--shadow);
    }
    
    .nav-links.active {
        right: 0;
    }
    
    .nav-links a {
        font-size: 1.2rem;
    }
    
    .menu-toggle {
        display: flex;
        z-index: 1001;
    }
    
    .hero-content {
        padding: 0 10px;
    }
    
    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .btn {
        width: 100%;
        max-width: 280px;
        justify-content: center;
    }
    
    .section {
        padding: 60px 0;
    }
    
    .footer-grid {
        grid-template-columns: 1fr;
        gap: 30px;
    }
    
    .footer-bottom {
        flex-direction: column;
        text-align: center;
    }
    
    .stats-grid {
        grid-template-columns: 1fr 1fr;
    }
    
    .stat-number {
        font-size: 2.5rem;
    }
    
    .phone-mockup {
        width: 250px;
        height: 500px;
    }
}

@media (max-width: 480px) {
    .logo-text {
        font-size: 1.2rem;
    }
    
    h1 {
        font-size: 2rem;
    }
    
    h2 {
        font-size: 1.75rem;
    }
    
    .services-grid {
        grid-template-columns: 1fr;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .about-grid {
        grid-template-columns: 1fr;
    }
}

/* Utility Classes */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }
.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }
.mt-0 { margin-top: 0; }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }