/* =============================================
   YIFAN LCT LIMITED - 官网样式
   ============================================= */

/* ---------- CSS Variables ---------- */
:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #3b82f6;
    --secondary: #06b6d4;
    --accent: #8b5cf6;
    --dark: #0f172a;
    --dark-2: #1e293b;
    --dark-3: #334155;
    --light: #f8fafc;
    --light-2: #f1f5f9;
    --white: #ffffff;
    --gray: #94a3b8;
    --gray-dark: #64748b;
    --gradient: linear-gradient(135deg, #2563eb 0%, #06b6d4 50%, #8b5cf6 100%);
    --gradient-2: linear-gradient(135deg, #1e293b 0%, #0f172a 100%);
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
    --shadow-md: 0 4px 20px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 40px rgba(0,0,0,0.12);
    --shadow-xl: 0 20px 60px rgba(0,0,0,0.15);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-xl: 28px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

/* ---------- Reset ---------- */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 80px; }
body {
    font-family: var(--font);
    color: var(--dark);
    background: var(--white);
    line-height: 1.7;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}
a { text-decoration: none; color: inherit; }
ul { list-style: none; }
img { max-width: 100%; display: block; }
button { cursor: pointer; font-family: inherit; border: none; background: none; }
input, textarea { font-family: inherit; }

/* ---------- Container ---------- */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ---------- Section ---------- */
.section { padding: 100px 0; }
.section-dark { background: var(--dark); color: var(--white); }
.section-light { background: var(--light-2); }
.section-gradient {
    background: var(--gradient);
    color: var(--white);
}

/* ---------- Section Header ---------- */
.section-header { text-align: center; margin-bottom: 60px; }
.section-tag {
    display: inline-block;
    font-size: 13px;
    font-weight: 600;
    letter-spacing: 3px;
    color: var(--primary);
    background: rgba(37,99,235,0.08);
    padding: 6px 16px;
    border-radius: 50px;
    margin-bottom: 16px;
    text-transform: uppercase;
}
.section-dark .section-tag { color: var(--secondary); background: rgba(6,182,212,0.15); }
.section-title {
    font-size: 42px;
    font-weight: 800;
    margin-bottom: 16px;
    line-height: 1.2;
}
.section-dark .section-title { color: var(--white); }
.gradient-text {
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.section-desc {
    font-size: 17px;
    color: var(--gray-dark);
    max-width: 600px;
    margin: 0 auto;
}
.section-dark .section-desc { color: var(--gray); }

/* =========================================
   NAVBAR
   ========================================= */
.navbar {
    position: fixed;
    top: 0; left: 0; right: 0;
    z-index: 1000;
    padding: 16px 0;
    transition: var(--transition);
    background: transparent;
}
.navbar.scrolled {
    background: rgba(255,255,255,0.95);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    box-shadow: var(--shadow-sm);
    padding: 10px 0;
}
.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
}
.nav-logo {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 22px;
    font-weight: 800;
    color: var(--white);
    transition: var(--transition);
}
.navbar.scrolled .nav-logo { color: var(--dark); }
.logo-icon { font-size: 28px; }
.nav-menu { display: flex; gap: 4px; }
.nav-link {
    padding: 8px 18px;
    font-size: 15px;
    font-weight: 500;
    color: rgba(255,255,255,0.8);
    border-radius: 8px;
    transition: var(--transition);
    position: relative;
}
.navbar.scrolled .nav-link { color: var(--dark-3); }
.nav-link:hover, .nav-link.active {
    color: var(--white);
    background: rgba(255,255,255,0.15);
}
.navbar.scrolled .nav-link:hover,
.navbar.scrolled .nav-link.active {
    color: var(--primary);
    background: rgba(37,99,235,0.08);
}

/* Mobile Toggle */
.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    padding: 4px;
    z-index: 1001;
}
.nav-toggle span {
    width: 26px; height: 2px;
    background: var(--white);
    transition: var(--transition);
    border-radius: 2px;
}
.navbar.scrolled .nav-toggle span { background: var(--dark); }

/* =========================================
   HERO
   ========================================= */
.hero {
    min-height: 100vh;
    background: var(--gradient-2);
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    position: relative;
    overflow: hidden;
    padding: 120px 0 80px;
}
.hero-particles {
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    pointer-events: none;
}
.particle {
    position: absolute;
    border-radius: 50%;
    background: rgba(37,99,235,0.3);
    animation: float 6s ease-in-out infinite;
}
@keyframes float {
    0%, 100% { transform: translateY(0) scale(1); opacity: 0.3; }
    50% { transform: translateY(-40px) scale(1.3); opacity: 0.6; }
}

.hero-content { position: relative; z-index: 2; }
.hero-badge {
    display: inline-block;
    font-size: 13px;
    font-weight: 600;
    letter-spacing: 2px;
    color: var(--secondary);
    background: rgba(6,182,212,0.12);
    border: 1px solid rgba(6,182,212,0.25);
    padding: 8px 20px;
    border-radius: 50px;
    margin-bottom: 28px;
}
.hero-title {
    font-size: 64px;
    font-weight: 900;
    color: var(--white);
    line-height: 1.15;
    margin-bottom: 24px;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}
.hero-desc {
    font-size: 18px;
    color: var(--gray);
    line-height: 1.8;
    max-width: 680px;
    margin: 0 auto 40px;
}

/* Hero Buttons */
.hero-btns {
    display: flex;
    gap: 16px;
    justify-content: center;
    margin-bottom: 60px;
    flex-wrap: wrap;
}
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 32px;
    font-size: 16px;
    font-weight: 600;
    border-radius: 50px;
    transition: var(--transition);
    cursor: pointer;
    border: none;
}
.btn-primary {
    background: var(--primary);
    color: var(--white);
}
.btn-primary:hover { background: var(--primary-dark); transform: translateY(-2px); box-shadow: 0 6px 24px rgba(37,99,235,0.35); }
.btn-outline {
    border: 2px solid rgba(255,255,255,0.25);
    color: var(--white);
}
.btn-outline:hover { border-color: var(--white); background: rgba(255,255,255,0.1); transform: translateY(-2px); }
.btn-full { width: 100%; justify-content: center; }

/* Hero Stats */
.hero-stats {
    display: flex;
    justify-content: center;
    gap: 48px;
    flex-wrap: wrap;
}
.stat-item {
    text-align: center;
    color: var(--white);
    font-weight: 700;
    font-size: 36px;
}
.stat-item span:nth-child(2) { color: var(--secondary); }
.stat-label {
    display: block;
    font-size: 14px;
    font-weight: 400;
    color: var(--gray);
    margin-top: 4px;
}

/* Hero Scroll */
.hero-scroll {
    position: absolute;
    bottom: 32px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 6px;
    color: var(--gray);
    font-size: 12px;
    letter-spacing: 1px;
    animation: bounce 2s ease-in-out infinite;
}
@keyframes bounce {
    0%, 100% { transform: translateX(-50%) translateY(0); }
    50% { transform: translateX(-50%) translateY(-8px); }
}

/* =========================================
   ABOUT
   ========================================= */
.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}
.about-image { position: relative; }
.about-img-main {
    width: 100%;
    height: 420px;
    border-radius: var(--radius-lg);
    /* background: linear-gradient(135deg, #2563eb 0%, #06b6d4 50%, #8b5cf6 100%); */
     background: url("../images/bg.png") center/cover no-repeat;
    position: relative;
    overflow: hidden;
}
.about-img-main::after {
    content: '';
    position: absolute;
    inset: 0;
}
.about-img-float {
    position: absolute;
    bottom: -20px;
    right: -20px;
}
.float-card {
    background: var(--white);
    padding: 24px 32px;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    text-align: center;
}
.float-number { font-size: 36px; font-weight: 800; color: var(--primary); display: block; }
.float-label { font-size: 14px; color: var(--gray-dark); }

.about-content h3 {
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 20px;
    color: var(--dark);
}
.about-content p {
    color: var(--dark-3);
    font-size: 16px;
    margin-bottom: 16px;
    line-height: 1.8;
}
.about-features { margin-top: 28px; display: flex; flex-direction: column; gap: 14px; }
.feature-item {
    display: flex;
    align-items: flex-start;
    gap: 14px;
}
.feature-icon {
    flex-shrink: 0;
    width: 44px; height: 44px;
    background: rgba(37,99,235,0.08);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--primary);
}
.feature-icon svg { width: 22px; height: 22px; }
.feature-item strong { display: block; font-size: 15px; margin-bottom: 2px; }
.feature-item p { font-size: 13px; color: var(--gray-dark); margin: 0; }

/* =========================================
   BUSINESS CARDS
   ========================================= */
.business-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}
.business-card {
    background: var(--dark-2);
    border: 1px solid rgba(255,255,255,0.06);
    border-radius: var(--radius-lg);
    padding: 36px 28px;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}
.business-card::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 3px;
    background: var(--gradient);
    transform: scaleX(0);
    transform-origin: left;
    transition: transform 0.4s ease;
}
.business-card:hover::before { transform: scaleX(1); }
.business-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 20px 50px rgba(0,0,0,0.3);
    border-color: rgba(255,255,255,0.12);
}
.card-icon {
    width: 60px; height: 60px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
}
.card-icon svg { width: 36px; height: 36px; }
.card-icon.blue { background: rgba(37,99,235,0.15); color: #60a5fa; }
.card-icon.green { background: rgba(16,185,129,0.15); color: #34d399; }
.card-icon.purple { background: rgba(139,92,246,0.15); color: #a78bfa; }
.card-icon.orange { background: rgba(249,115,22,0.15); color: #fb923c; }
.card-icon.cyan { background: rgba(6,182,212,0.15); color: #22d3ee; }
.card-icon.red { background: rgba(239,68,68,0.15); color: #f87171; }
.card-icon.pink { background: rgba(236,72,153,0.15); color: #f472b6; }
.card-icon.indigo { background: rgba(99,102,241,0.15); color: #818cf8; }
.card-icon.amber { background: rgba(245,158,11,0.15); color: #fbbf24; }

.business-card h3 { font-size: 20px; font-weight: 700; margin-bottom: 12px; color: var(--white); }
.business-card p { font-size: 14px; color: var(--gray); line-height: 1.7; margin-bottom: 18px; }
.card-link { font-size: 14px; font-weight: 600; color: var(--secondary); transition: var(--transition); }
.card-link:hover { color: var(--white); }

/* =========================================
   SERVICES TIMELINE
   ========================================= */
.services-timeline {
    position: relative;
    max-width: 800px;
    margin: 0 auto;
}
.services-timeline::before {
    content: '';
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    top: 0; bottom: 0;
    width: 2px;
    background: linear-gradient(to bottom, transparent, var(--primary), var(--secondary), transparent);
}
.service-item {
    display: flex;
    align-items: center;
    margin-bottom: 40px;
    position: relative;
}
.service-item:last-child { margin-bottom: 0; }
.service-item.left { justify-content: flex-start; }
.service-item.right { justify-content: flex-end; }
.service-dot {
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    width: 16px; height: 16px;
    border-radius: 50%;
    background: var(--white);
    border: 3px solid var(--primary);
    z-index: 2;
}
.service-card {
    width: 44%;
    background: var(--white);
    border: 1px solid #e2e8f0;
    border-radius: var(--radius-lg);
    padding: 28px 24px;
    transition: var(--transition);
    position: relative;
}
.service-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}
.service-step {
    font-size: 13px;
    font-weight: 700;
    color: var(--primary);
    letter-spacing: 2px;
    display: block;
    margin-bottom: 8px;
}
.service-card h3 { font-size: 20px; font-weight: 700; margin-bottom: 8px; }
.service-card p { font-size: 14px; color: var(--gray-dark); line-height: 1.7; }

/* =========================================
   COUNTER
   ========================================= */
.counter-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 40px;
    text-align: center;
}
.counter-number {
    font-size: 56px;
    font-weight: 900;
    line-height: 1;
    margin-bottom: 8px;
}
.counter-number span { font-size: 28px; }
.counter-label { font-size: 15px; opacity: 0.85; font-weight: 500; }

/* =========================================
   NEWS
   ========================================= */
.news-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
    align-items: start;
}
.news-card {
    background: var(--white);
    border: 1px solid #e2e8f0;
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: var(--transition);
}
.news-card:hover { box-shadow: var(--shadow-lg); transform: translateY(-4px); }
.news-img {
    height: 220px;
    background: linear-gradient(135deg, #2563eb 0%, #06b6d4 100%);
}
.news-card.featured .news-img {
    background: linear-gradient(135deg, #1e40af 0%, #0891b2 100%);
}
.news-body { padding: 24px; }
.news-date { font-size: 13px; color: var(--primary); font-weight: 600; }
.news-body h3 { font-size: 20px; font-weight: 700; margin: 8px 0 10px; line-height: 1.4; }
.news-body p { font-size: 14px; color: var(--gray-dark); line-height: 1.6; margin-bottom: 14px; }
.news-link { font-size: 14px; font-weight: 600; color: var(--primary); }
.news-link:hover { text-decoration: underline; }
.news-list { display: flex; flex-direction: column; gap: 16px; }
.news-item {
    display: flex;
    gap: 16px;
    background: var(--white);
    border: 1px solid #e2e8f0;
    border-radius: var(--radius-md);
    padding: 18px;
    transition: var(--transition);
    cursor: pointer;
}
.news-item:hover { box-shadow: var(--shadow-md); transform: translateX(4px); }
.news-item-date {
    flex-shrink: 0;
    font-size: 14px;
    font-weight: 700;
    color: var(--primary);
    min-width: 60px;
}
.news-item-content h4 { font-size: 15px; font-weight: 600; margin-bottom: 4px; line-height: 1.4; }
.news-item-content p { font-size: 13px; color: var(--gray-dark); }

/* =========================================
   CONTACT
   ========================================= */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1.2fr;
    gap: 48px;
}
.contact-info h3, .contact-form h3 {
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 12px;
}
.contact-info > p {
    font-size: 15px;
    color: var(--gray-dark);
    margin-bottom: 28px;
    line-height: 1.6;
}
.contact-details { display: flex; flex-direction: column; gap: 18px; }
.contact-detail {
    display: flex;
    gap: 14px;
    align-items: flex-start;
}
.contact-icon {
    flex-shrink: 0;
    width: 44px; height: 44px;
    background: var(--white);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--primary);
}
.contact-icon svg { width: 20px; height: 20px; }
.contact-detail strong { font-size: 14px; display: block; margin-bottom: 2px; }
.contact-detail p { font-size: 14px; color: var(--gray-dark); }

.contact-form {
    background: var(--white);
    padding: 36px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.form-group { margin-bottom: 16px; }
.form-group label {
    display: block;
    font-size: 14px;
    font-weight: 600;
    color: var(--dark);
    margin-bottom: 6px;
}
.form-group input, .form-group textarea {
    width: 100%;
    padding: 12px 16px;
    border: 1.5px solid #e2e8f0;
    border-radius: var(--radius-sm);
    font-size: 15px;
    transition: var(--transition);
    background: var(--light);
}
.form-group input:focus, .form-group textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(37,99,235,0.1);
    background: var(--white);
}
.form-group textarea { resize: vertical; min-height: 120px; }

/* =========================================
   FOOTER
   ========================================= */
.footer {
    background: var(--dark);
    color: var(--gray);
    padding: 64px 0 24px;
}
.footer-grid {
    display: grid;
    grid-template-columns: 1.5fr 1fr 1fr 1fr;
    gap: 40px;
    padding-bottom: 40px;
    border-bottom: 1px solid rgba(255,255,255,0.08);
    margin-bottom: 24px;
}
.footer-logo {
    font-size: 24px;
    font-weight: 800;
    color: var(--white);
    display: inline-flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 16px;
}
.footer-brand p { font-size: 14px; line-height: 1.7; margin-bottom: 20px; }
.footer-social { display: flex; gap: 12px; }
.footer-social a {
    width: 40px; height: 40px;
    border-radius: 50%;
    background: rgba(255,255,255,0.06);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
    color: var(--gray);
}
.footer-social a svg { width: 18px; height: 18px; }
.footer-social a:hover { background: var(--primary); color: var(--white); transform: translateY(-2px); }
.footer-links h4 {
    font-size: 15px;
    font-weight: 700;
    color: var(--white);
    margin-bottom: 16px;
}
.footer-links ul { display: flex; flex-direction: column; gap: 10px; }
.footer-links a { font-size: 14px; color: var(--gray); transition: var(--transition); }
.footer-links a:hover { color: var(--white); padding-left: 4px; }
.footer-bottom {
    text-align: center;
    font-size: 13px;
    color: var(--gray-dark);
}

/* =========================================
   BACK TO TOP
   ========================================= */
.back-to-top {
    position: fixed;
    bottom: 32px;
    right: 32px;
    width: 48px; height: 48px;
    border-radius: 50%;
    background: var(--primary);
    color: var(--white);
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-md);
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
    z-index: 999;
}
.back-to-top.visible { opacity: 1; visibility: visible; }
.back-to-top:hover { background: var(--primary-dark); transform: translateY(-2px); box-shadow: var(--shadow-lg); }

/* =========================================
   REVEAL ANIMATION
   ========================================= */
.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.8s ease, transform 0.8s ease;
}
.reveal.revealed {
    opacity: 1;
    transform: translateY(0);
}

/* =========================================
   RESPONSIVE
   ========================================= */
@media (max-width: 1024px) {
    .business-grid { grid-template-columns: repeat(2, 1fr); }
    .footer-grid { grid-template-columns: 1fr 1fr; }
    .news-grid { grid-template-columns: 1fr; }
}

@media (max-width: 768px) {
    .hero-title { font-size: 40px; }
    .hero-stats { gap: 24px; }
    .stat-item { font-size: 28px; }
    .section-title { font-size: 32px; }
    .section { padding: 64px 0; }

    .nav-toggle { display: flex; }
    .nav-menu {
        position: fixed;
        top: 0; right: -100%;
        width: 280px;
        height: 100vh;
        background: var(--white);
        flex-direction: column;
        padding: 80px 28px 28px;
        gap: 4px;
        transition: var(--transition);
        box-shadow: var(--shadow-xl);
    }
    .nav-menu.active { right: 0; }
    .nav-menu .nav-link { color: var(--dark); width: 100%; padding: 12px 16px; }
    .nav-menu .nav-link:hover, .nav-menu .nav-link.active {
        background: rgba(37,99,235,0.08);
        color: var(--primary);
    }

    .about-grid { grid-template-columns: 1fr; gap: 32px; }
    .about-img-main { height: 300px; }
    .about-img-float { right: 0; bottom: -10px; }
    .float-card { padding: 16px 24px; }
    .float-number { font-size: 28px; }

    .business-grid { grid-template-columns: 1fr; }
    .counter-grid { grid-template-columns: repeat(2, 1fr); gap: 24px; }
    .counter-number { font-size: 40px; }
    .contact-grid { grid-template-columns: 1fr; }
    .form-row { grid-template-columns: 1fr; }
    .services-timeline::before { left: 24px; }
    .service-dot { left: 24px; }
    .service-item.left, .service-item.right { justify-content: flex-end; }
    .service-card { width: 82%; }

    .footer-grid { grid-template-columns: 1fr; text-align: center; }
    .footer-social { justify-content: center; }
}

@media (max-width: 480px) {
    .hero-title { font-size: 32px; }
    .hero-desc { font-size: 15px; }
    .hero-stats { flex-direction: column; gap: 16px; }
    .section-title { font-size: 28px; }
    .container { padding: 0 16px; }
}