:root {
    --primary-dark: #0a0f1c;
    --secondary-dark: #111827;
    --accent-gold: #d4af37;
    --accent-gold-light: #f4d03f;
    --accent-blue: #1e40af;
    --text-white: #ffffff;
    --text-gray: #9ca3af;
    --text-light: #e5e7eb;
    --gradient-dark: linear-gradient(135deg, #0a0f1c 0%, #1e293b 100%);
    --gradient-gold: linear-gradient(135deg, #d4af37 0%, #f4d03f 100%);
    --shadow-soft: 0 4px 20px rgba(0, 0, 0, 0.3);
    --shadow-glow: 0 0 30px rgba(212, 175, 55, 0.2);
    --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1)
}

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

html {
    scroll-behavior: smooth
}

body {
    font-family: 'Inter', 'Segoe UI', system-ui, -apple-system, sans-serif;
    background: var(--primary-dark);
    color: var(--text-white);
    line-height: 1.6;
    overflow-x: hidden
}

.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: var(--transition-smooth);
    background: transparent
}

.navbar.scrolled {
    background: rgba(10, 15, 28, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.3)
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 1rem
}

.nav-logo img {
    height: 50px;
    width: 50px;
    object-fit: cover;
    border-radius: 8px
}

.nav-logo-text {
    display: flex;
    flex-direction: column
}

.nav-logo-text .company-name {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--text-white);
    letter-spacing: 1px
}

.nav-logo-text .company-tagline {
    font-size: 0.75rem;
    color: var(--accent-gold)
}

.nav-links {
    display: flex;
    gap: 2.5rem;
    list-style: none
}

.nav-links a {
    color: var(--text-gray);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.95rem;
    transition: var(--transition-smooth);
    position: relative
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent-gold);
    transition: var(--transition-smooth)
}

.nav-links a:hover {
    color: var(--text-white)
}

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

.nav-links a.active {
    color: var(--text-white)
}

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

.nav-right {
    display: flex;
    align-items: center;
    gap: 1.5rem
}

.nav-email {
    color: var(--text-gray);
    font-size: 0.85rem
}

.lang-switch {
    display: flex;
    align-items: center;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 20px;
    padding: 3px;
    gap: 2px
}

.lang-btn {
    padding: 4px 10px;
    border-radius: 15px;
    font-size: 0.7rem;
    font-weight: 600;
    text-decoration: none;
    color: var(--text-gray);
    transition: all 0.3s ease;
    letter-spacing: 0.5px
}

.lang-btn:hover {
    color: var(--text-white)
}

.lang-btn.active {
    background: var(--gradient-gold);
    color: var(--primary-dark);
    box-shadow: 0 2px 10px rgba(212, 175, 55, 0.3)
}

.mobile-lang-switch {
    display: flex;
    gap: 0.5rem;
    margin-top: 2rem;
    padding: 3px;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 20px
}

.mobile-lang-switch a, .mobile-lang-switch span {
    padding: 6px 16px;
    border-radius: 15px;
    font-size: 0.85rem;
    font-weight: 600;
    text-decoration: none;
    color: var(--text-gray);
    transition: all 0.3s ease
}

.mobile-lang-switch a:hover {
    color: var(--text-white)
}

.mobile-lang-switch .active {
    background: var(--gradient-gold);
    color: var(--primary-dark)
}

/* 临时禁用中文切换: 任何指向 cn/ 的链接都不响应点击, 视觉置灰
   恢复方法: 删掉本规则即可 */
.lang-switch a[href^="cn/"],
.mobile-lang-switch a[href^="cn/"] {
    pointer-events: none;
    opacity: 0.5;
    cursor: not-allowed
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    color: var(--text-white);
    font-size: 1.5rem;
    cursor: pointer
}

.btn {
    padding: 0.8rem 2rem;
    border-radius: 50px;
    font-weight: 600;
    font-size: 0.9rem;
    text-decoration: none;
    transition: var(--transition-smooth);
    display: inline-flex;
    align-items: center;
    gap: 0.5rem
}

.btn-primary {
    background: var(--gradient-gold);
    color: var(--primary-dark);
    box-shadow: var(--shadow-glow)
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 0 40px rgba(212, 175, 55, 0.4)
}

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

.btn-secondary:hover {
    border-color: var(--accent-gold);
    color: var(--accent-gold)
}

.scroll-indicator {
    animation: bounce-center 2s infinite
}

.scroll-indicator span {
    display: block;
    width: 24px;
    height: 40px;
    border: 2px solid var(--accent-gold);
    border-radius: 25px;
    position: relative
}

.scroll-indicator span::before {
    content: '';
    position: absolute;
    top: 8px;
    left: 50%;
    transform: translateX(-50%);
    width: 6px;
    height: 6px;
    background: var(--accent-gold);
    border-radius: 50%;
    animation: scrollDot 2s infinite
}

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

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

@keyframes scrollDot {
    0% {
        top: 8px;
        opacity: 1
    }
    100% {
        top: 30px;
        opacity: 0
    }
}

.hero {
    height: 100vh;
    min-height: 700px;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden
}

.hero-buttons .scroll-indicator {
    position: relative;
    bottom: auto;
    left: auto;
    transform: none !important;
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 0 1.5rem;
    flex-shrink: 0
}

.hero-slider {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%
}

.hero-slide {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    opacity: 0;
    transition: opacity 1.5s ease-in-out;
    background-size: cover;
    background-position: center
}

.hero-slide.active {
    opacity: 1
}

.hero-slide::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, rgba(10, 15, 28, 0.85) 0%, rgba(17, 24, 39, 0.7) 100%)
}

.hero-content {
    position: relative;
    z-index: 10;
    text-align: center;
    max-width: 900px;
    padding: 0 2rem
}

.hero-subtitle {
    margin-top: 50px;
    font-size: 1rem;
    text-transform: uppercase;
    letter-spacing: 4px;
    color: var(--accent-gold);
    margin-bottom: 1.5rem;
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 0.8s ease forwards 0.3s
}

.hero-title {
    margin-top: 40px;
    font-size: clamp(2.2rem, 5vw, 4rem);
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 1.5rem;
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 0.8s ease forwards 0.5s
}

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

.hero-title .subtitle-line {
    font-size: 0.7em;
    font-weight: 400;
    letter-spacing: 0.5px;
    color: var(--text-light)
}

.hero-description {
    font-size: 1.15rem;
    color: var(--text-light);
    max-width: 800px;
    margin: 0 auto 1rem;
    line-height: 1.8;
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 0.8s ease forwards 0.7s
}

.hero-buttons {
    display: flex;
    gap: 1.5rem;
    justify-content: center;
    align-items: center;
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 0.8s ease forwards 0.9s
}

/* section */
.section {
    /*border: 1px solid red;*/
    padding: 80px 0;
    position: relative
}

/* div */
.section-header {
    text-align: center;
    margin-bottom: 4rem
}

/* p */
.section-subtitle {
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 3px;
    color: var(--accent-gold);
    margin-bottom: 1rem
}

/* h2 */
.section-title {
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 700;
    margin-bottom: 1rem
}

/* p */
.section-desc {
    color: var(--text-gray);
    max-width: 600px;
    margin: 0 auto
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem
}

.updates {
    background: var(--secondary-dark)
}

.about {
    background: var(--secondary-dark)
}

.clients {
    background: var(--secondary-dark)
}

.clients-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    margin: 3rem auto 0;
    max-width: 1000px;
    text-align: left
}

.client-card {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    background: var(--primary-dark);
    border: 1px solid rgba(212, 175, 55, 0.15);
    border-radius: 12px;
    padding: 1.75rem 2rem;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden
}

.client-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 3px;
    height: 0;
    background: var(--accent-gold);
    transition: height 0.4s ease
}

.client-card:hover {
    border-color: var(--accent-gold);
    transform: translateY(-4px);
    box-shadow: 0 10px 30px rgba(212, 175, 55, 0.1)
}

.client-card:hover::before {
    height: 100%
}

.client-tag {
    flex-shrink: 0;
    width: 64px;
    height: 64px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(212, 175, 55, 0.1);
    border: 1px solid rgba(212, 175, 55, 0.3);
    border-radius: 12px;
    color: var(--accent-gold);
    font-size: 0.95rem;
    font-weight: 700;
    letter-spacing: 1px
}

.client-tag img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    padding: 6px;
}

.client-info h3 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-white);
    margin-bottom: 0.3rem
}

.client-info p {
    color: var(--text-gray);
    font-size: 0.9rem
}

.about-grid {
    display: grid;
    grid-template-columns:1fr 1fr;
    gap: 4rem;
    align-items: center
}

.about-image {
    position: relative;
    border-radius: 20px;
    overflow: hidden
}

.about-image img {
    width: 100%;
    height: 400px;
    object-fit: cover;
    transition: var(--transition-smooth)
}

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

.about-image::before {
    content: '';
    position: absolute;
    top: 20px;
    left: 20px;
    right: -20px;
    bottom: -20px;
    border: 3px solid var(--accent-gold);
    border-radius: 20px;
    z-index: -1
}

.about-content h3 {
    font-size: 2rem;
    margin-bottom: 1.5rem
}

.about-content p {
    color: var(--text-gray);
    margin-bottom: 1.5rem;
    line-height: 1.8
}

.about-features {
    display: grid;
    grid-template-columns:repeat(2, 1fr);
    gap: 1.5rem;
    margin-top: 2rem
}

.feature-item {
    display: flex;
    align-items: center;
    gap: 1rem
}

.feature-icon {
    width: 50px;
    height: 50px;
    background: rgba(212, 175, 55, 0.1);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent-gold);
    font-size: 1.5rem
}

.feature-item span {
    font-weight: 600
}

/* Specialize layout (PC) */
.specialize-layout {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 2rem;
    align-items: stretch;
    margin-top: 3rem;
    text-align: left
}

.specialize-intro {
    background: var(--primary-dark);
    border-left: 3px solid var(--accent-gold);
    border-radius: 0 12px 12px 0;
    padding: 2.5rem;
    display: flex;
    flex-direction: column;
    justify-content: center
}

.specialize-label {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--text-white);
    text-transform: uppercase;
    letter-spacing: 2px;
    line-height: 1.2;
    margin-bottom: 1.5rem;
    white-space: nowrap
}

.specialize-label::after {
    content: '';
    display: block;
    width: 50px;
    height: 3px;
    background: var(--accent-gold);
    margin-top: 1rem
}

.specialize-desc {
    color: var(--text-gray);
    line-height: 1.8;
    font-size: 1rem
}

.specialize-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.25rem
}

.specialize-card {
    background: var(--primary-dark);
    border: 1px solid rgba(212, 175, 55, 0.15);
    border-radius: 12px;
    padding: 2rem;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden
}

.specialize-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 3px;
    height: 0;
    background: var(--accent-gold);
    transition: height 0.4s ease
}

.specialize-card:hover {
    border-color: var(--accent-gold);
    transform: translateY(-4px);
    box-shadow: 0 10px 30px rgba(212, 175, 55, 0.1)
}

.specialize-card:hover::before {
    height: 100%
}

.specialize-num {
    display: inline-block;
    font-size: 0.8rem;
    font-weight: 700;
    color: var(--accent-gold);
    letter-spacing: 2px;
    margin-bottom: 1rem;
    padding: 0.3rem 0.75rem;
    background: rgba(212, 175, 55, 0.1);
    border-radius: 4px
}

.specialize-card h3 {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-white);
    margin-bottom: 0.5rem
}

.specialize-card p {
    color: var(--text-gray);
    font-size: 0.9rem;
    line-height: 1.6
}

.services-grid {
    display: grid;
    grid-template-columns:repeat(3, 1fr);
    gap: 2rem
}

.service-card {
    background: var(--secondary-dark);
    border-radius: 20px;
    padding: 2.5rem;
    text-align: center;
    transition: var(--transition-smooth);
    position: relative;
    overflow: hidden
}

.service-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: var(--gradient-gold);
    transform: scaleX(0);
    transition: var(--transition-smooth)
}

.service-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-glow)
}

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

.service-icon {
    width: 80px;
    height: 80px;
    background: rgba(212, 175, 55, 0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.5rem;
    font-size: 2rem;
    color: var(--accent-gold)
}

.service-card h3 {
    font-size: 1.3rem;
    margin-bottom: 1rem
}

.service-card p {
    color: var(--text-gray);
    font-size: 0.95rem
}

.projects {
    background: var(--secondary-dark);
    _padding-top: 60px
}

.csr {
    background: var(--secondary-dark);
}

.projects-grid {
    display: grid;
    grid-template-columns:repeat(2, 1fr);
    gap: 2rem
}

.project-card {
    position: relative;
    border-radius: 20px;
    overflow: hidden;
    height: 350px;
    cursor: pointer
}

.project-card img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: var(--transition-smooth)
}

.project-card:hover img {
    transform: scale(1.1)
}

.project-overlay {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    padding: 2rem;
    background: linear-gradient(transparent, rgba(10, 15, 28, 0.95))
}

.project-overlay h3 {
    font-size: 1.3rem;
    margin-bottom: 0.5rem
}

.project-overlay h3 a {
    color: var(--text-white);
    text-decoration: none
}

.project-overlay h3 a:hover {
    color: var(--accent-gold)
}

.project-overlay span {
    color: var(--accent-gold);
    font-size: 0.9rem
}

.culture-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center
}

.culture-image {
    width: 100%;
    max-width: 800px;
    margin-bottom: 3rem;
    border-radius: 20px;
    overflow: hidden
}

.culture-image img {
    width: 100%;
    height: auto
}

.culture-values {
    display: grid;
    grid-template-columns:repeat(4, 1fr);
    gap: 2rem;
    margin-top: 3rem
}

.value-item {
    padding: 2rem;
    background: var(--secondary-dark);
    border-radius: 15px;
    transition: var(--transition-smooth)
}

.value-item:hover {
    transform: translateY(-5px);
    background: rgba(212, 175, 55, 0.1)
}

.value-item .value-number {
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--accent-gold);
    margin-bottom: 0.5rem
}

.value-item h4 {
    font-size: 1.1rem;
    margin-bottom: 0.5rem
}

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

.stats {
    background: var(--gradient-gold);
    padding: 20px 0
}

.stats-grid {
    display: grid;
    grid-template-columns:repeat(5, 1fr);
    gap: 2rem;
    text-align: center;
    flex-wrap: nowrap;
    align-items: center;
    min-height: 80px
}

.stat-item {
    position: relative;
    padding: 0 0.5rem;
    display: flex;
    align-items: center;
    justify-content: center
}

.stat-item:not(:last-child)::after {
    content: '';
    position: absolute;
    right: -1rem;
    width: 2px;
    height: 60px;
    background: rgba(10, 15, 28, 0.3);
    transform: rotate(20deg)
}

.stat-item p {
    color: rgba(10, 15, 28, 0.85);
    font-weight: 500;
    font-size: 1rem;
    line-height: 1.4
}

.stat-item .highlight {
    color: var(--primary-dark);
    font-weight: 800;
    text-shadow: 0 0 10px rgba(10, 15, 28, 0.2)
}

.contact {
    background: var(--primary-dark)
}

.contact-grid {
    display: grid;
    grid-template-columns:1fr 1fr;
    gap: 4rem
}

.contact-info h3 {
    font-size: 1.8rem;
    margin-bottom: 2rem
}

.contact-item {
    display: flex;
    align-items: flex-start;
    gap: 1.5rem;
    margin-bottom: 2rem
}

.contact-item .icon {
    width: 50px;
    height: 50px;
    background: rgba(212, 175, 55, 0.1);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent-gold);
    font-size: 1.3rem;
    flex-shrink: 0
}

.contact-item h4 {
    font-size: 1rem;
    margin-bottom: 0.3rem
}

.contact-item p {
    color: var(--text-gray)
}

.contact-form {
    background: var(--secondary-dark);
    padding: 3rem;
    border-radius: 20px
}

.form-group {
    margin-bottom: 1.5rem
}

.form-group input, .form-group textarea {
    width: 100%;
    padding: 1rem 1.5rem;
    background: var(--primary-dark);
    border: 2px solid transparent;
    border-radius: 12px;
    color: var(--text-white);
    font-size: 1rem;
    transition: var(--transition-smooth)
}

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

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

.form-btn {
    width: 100%;
    padding: 1rem;
    background: var(--gradient-gold);
    color: var(--primary-dark);
    border: none;
    border-radius: 12px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-smooth)
}

.form-btn:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-glow)
}

.footer {
    background: var(--secondary-dark);
    padding: 4rem 0 2rem
}

.footer-content {
    display: grid;
    grid-template-columns:1.6fr 0.6fr 0.6fr 1.6fr;
    gap: 3rem;
    padding-bottom: 2rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1)
}

.footer-section h4 {
    color: var(--accent-gold);
    font-size: 1.1rem;
    margin-bottom: 1.5rem;
    font-weight: 600
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1rem
}

.footer-logo img {
    height: 50px;
    width: 50px;
    border-radius: 8px
}

.footer-logo-text {
    display: flex;
    flex-direction: column
}

.footer-logo-text .company-name {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--text-white)
}

.footer-logo-text .company-tagline {
    font-size: 0.8rem;
    color: var(--accent-gold)
}

.footer-about {
    color: var(--text-gray);
    font-size: 0.9rem;
    line-height: 1.7
}

.footer-links {
    display: flex;
    flex-direction: column;
    gap: 0.8rem
}

.footer-links a {
    color: var(--text-gray);
    text-decoration: none;
    transition: var(--transition-smooth);
    font-size: 0.9rem
}

.footer-links a:hover {
    color: var(--accent-gold)
}

.footer-contact-item {
    display: flex;
    align-items: flex-start;
    gap: 0.8rem;
    margin-bottom: 1rem;
    color: var(--text-gray);
    font-size: 0.85rem;
    line-height: 1.5
}

.footer-contact-item .icon {
    width: 35px;
    height: 35px;
    background: rgba(212, 175, 55, 0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent-gold);
    font-size: 0.9rem;
    flex-shrink: 0
}

.footer-social {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-top: 0.5rem
}

.footer-social a {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: rgba(212, 175, 55, 0.1);
    border: 1px solid rgba(212, 175, 55, 0.35);
    color: var(--accent-gold);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition-smooth);
    text-decoration: none
}

.footer-social a:hover {
    background: var(--accent-gold);
    color: var(--secondary-dark);
    transform: translateY(-2px)
}

.footer-social svg {
    width: 18px;
    height: 18px;
    fill: currentColor
}

.footer-bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 1.5rem;
    color: var(--text-gray);
    font-size: 0.85rem
}

.footer-bottom a {
    color: var(--text-gray);
    text-decoration: none
}

.footer-bottom a:hover {
    color: var(--accent-gold)
}

@media (max-width: 1024px) {
    .footer-content {
        grid-template-columns:1fr 1fr
    }
}

@media (max-width: 768px) {
    .footer-content {
        grid-template-columns:1fr;
        text-align: center
    }

    .footer-logo {
        justify-content: center
    }

    .footer-social {
        justify-content: center
    }

    .footer-bottom {
        flex-direction: column;
        gap: 0.5rem
    }
}

.back-to-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 50px;
    height: 50px;
    background: var(--accent-gold);
    color: var(--primary-dark);
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition-smooth);
    z-index: 999
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible
}

.back-to-top:hover {
    transform: translateY(-5px)
}

.reveal {
    opacity: 0;
    transform: translateY(50px);
    transition: all 0.8s ease
}

.reveal.active {
    opacity: 1;
    transform: translateY(0)
}

@media (max-width: 1024px) {
    .about-grid {
        grid-template-columns:1fr;
        gap: 3rem
    }

    .services-grid {
        grid-template-columns:repeat(2, 1fr)
    }

    .culture-values {
        grid-template-columns:repeat(2, 1fr)
    }

    .stats-grid {
        grid-template-columns:repeat(2, 1fr);
        gap: 2rem
    }

    .contact-grid {
        grid-template-columns:1fr
    }
}

@media (max-width: 768px) {
    .nav-links {
        display: none
    }

    .mobile-menu-btn {
        display: block
    }

    .hero-buttons {
        flex-direction: column;
        align-items: center
    }

    .services-grid, .projects-grid {
        grid-template-columns:1fr
    }

    .culture-values {
        grid-template-columns:1fr
    }

    .stats-grid {
        grid-template-columns:1fr;
        gap: 2rem
    }

    .footer-content {
        flex-direction: column;
        gap: 2rem;
        text-align: center
    }
}

.machinery {
    background: var(--primary-dark)
}

.section-footer {
    margin-top: 3rem
}

.mobile-menu {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(10, 15, 28, 0.98);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 2rem;
    z-index: 999;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition-smooth)
}

.mobile-menu.active {
    opacity: 1;
    visibility: visible
}

.mobile-menu a {
    color: var(--text-white);
    text-decoration: none;
    font-size: 1.5rem;
    font-weight: 600;
    transition: var(--transition-smooth)
}

.mobile-menu a:hover {
    color: var(--accent-gold)
}

.mobile-menu a.active {
    color: var(--accent-gold)
}

.mobile-menu-close {
    position: absolute;
    top: 2rem;
    right: 2rem;
    background: none;
    border: none;
    color: var(--text-white);
    font-size: 2rem;
    cursor: pointer
}

/* =========================================
   全局响应式系统（所有页面共享）
   ========================================= */

/* 1. 根字号：rem 基准，自动驱动全局缩放 */
html { font-size: 16px; }
@media (min-width: 2560px) { html { font-size: 18px; } }
@media (min-width: 3024px) { html { font-size: 21px; } }

/* 2. 大屏 2560 / 3024：容器 + 回顶按钮 */
@media (min-width: 2560px) {
    .container { max-width: 1800px; }
    .back-to-top {
        width: 4.5rem;
        height: 4.5rem;
        font-size: 1.5rem;
        bottom: 2.5rem;
        right: 2.5rem;
    }
}
@media (min-width: 3024px) {
    .container { max-width: 2200px; }
    .back-to-top {
        width: 5rem;
        height: 5rem;
        font-size: 1.8rem;
        bottom: 3rem;
        right: 3rem;
    }
}

/* 3. 平板 769-1024px：navbar 间距 */
@media (min-width: 769px) and (max-width: 1024px) {
    .navbar { padding: 0.8rem 1.2rem; }
    .nav-links { gap: 1.5rem; }
    .nav-links a { font-size: 0.9rem; }
    .footer { padding: 3rem 0 1.5rem; }
    .footer-content { gap: 2rem; }
}

/* 4. 手机 ≤768px：通用修复 */
@media (max-width: 768px) {
    /* Navbar 紧凑 */
    .navbar { padding: 0.7rem 1rem; }
    .nav-logo img { height: 40px; width: 40px; }
    .nav-logo-text .company-name { font-size: 0.9rem; }
    .nav-logo-text .company-tagline { font-size: 0.65rem; }

    /* 顶部 lang-switch 在手机端隐藏，避免与汉堡菜单重复 */
    .lang-switch { display: none; }
    .nav-right  { display: none; }

    /* 修复：mobile-menu 关闭按钮被 navbar 遮挡
       （navbar z-index 1000 > mobile-menu 999） */
    .mobile-menu { z-index: 1001; }
    .mobile-menu-close {
        z-index: 1002;
        top: 1.2rem;
        right: 1.2rem;
        font-size: 1.8rem;
    }
    body:has(.mobile-menu.active) .mobile-menu-btn {
        opacity: 0;
        pointer-events: none;
    }

    /* Section / Container 紧凑 */
    .section { padding: 50px 0; }
    .container { padding: 0 1rem; }
    .section-header { margin-bottom: 2.5rem; }

    /* Back to top */
    .back-to-top {
        width: 40px;
        height: 40px;
        font-size: 1rem;
        bottom: 1rem;
        right: 1rem;
    }
}

/* 5. 超小屏 ≤480px */
@media (max-width: 480px) {
    .container { padding: 0 0.85rem; }
    .section { padding: 45px 0; }
}