/* ============================================
   ONE PCBA - onepcba.cn
   Complete Stylesheet
   ============================================ */

/* === CSS Variables === */
:root {
    --primary: #1B8B4E;
    --primary-hover: #156E3E;
    --primary-light: #E8F5EE;
    --accent: #F08700;
    --text-dark: #333333;
    --text-muted: #666666;
    --white: #FFFFFF;
    --bg-light: #F8F9FA;
    --bg-dark: #0A1628;
    --bg-dark-alt: #132B48;
    --border: #E5E7EB;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 10px 40px rgba(0, 0, 0, 0.12);
    --radius: 12px;
    --radius-sm: 8px;
    --transition: all 0.3s ease;
}

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

html {
    scroll-behavior: smooth;
    scroll-padding-top: 80px;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-dark);
    background: var(--white);
    overflow-x: hidden;
}

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

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

ul {
    list-style: none;
}

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

/* === Buttons === */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px 28px;
    border-radius: var(--radius-sm);
    font-weight: 600;
    font-size: 15px;
    border: 2px solid transparent;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
}

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

.btn-primary:hover {
    background: var(--primary-hover);
    border-color: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(27, 139, 78, 0.35);
}

.btn-outline {
    background: transparent;
    color: var(--white);
    border-color: rgba(255, 255, 255, 0.5);
}

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

.btn-lg {
    padding: 14px 36px;
    font-size: 16px;
}

.btn-full {
    width: 100%;
}

/* === Navigation === */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    padding: 18px 0;
    transition: var(--transition);
}

.navbar.scrolled {
    background: var(--white);
    box-shadow: var(--shadow);
    padding: 12px 0;
}

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

.logo {
    font-size: 24px;
    font-weight: 800;
    letter-spacing: -0.5px;
}

.logo-one {
    color: var(--white);
    transition: var(--transition);
}

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

.navbar.scrolled .logo-one {
    color: var(--text-dark);
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 32px;
}

.nav-links a {
    color: rgba(255, 255, 255, 0.85);
    font-weight: 500;
    font-size: 14px;
    position: relative;
}

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

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

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

.navbar.scrolled .nav-links a {
    color: var(--text-muted);
}

.navbar.scrolled .nav-links a:hover {
    color: var(--primary);
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 16px;
}

.lang-switch {
    display: flex;
    align-items: center;
    gap: 4px;
}

.lang-btn {
    background: none;
    border: none;
    color: rgba(255, 255, 255, 0.6);
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    padding: 4px 8px;
    border-radius: 4px;
    transition: var(--transition);
}

.lang-btn.active {
    color: var(--white);
    background: rgba(255, 255, 255, 0.15);
}

.lang-sep {
    color: rgba(255, 255, 255, 0.4);
    font-size: 13px;
}

.navbar.scrolled .lang-btn {
    color: var(--text-muted);
}

.navbar.scrolled .lang-btn.active {
    color: var(--primary);
    background: var(--primary-light);
}

.navbar.scrolled .lang-sep {
    color: var(--border);
}

.nav-cta {
    padding: 10px 22px;
    font-size: 14px;
}

.mobile-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}

.mobile-toggle span {
    width: 24px;
    height: 2px;
    background: var(--white);
    transition: var(--transition);
    border-radius: 2px;
}

.navbar.scrolled .mobile-toggle span {
    background: var(--text-dark);
}

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

.hero-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, #0A1628 0%, #132B48 50%, #0D2237 100%);
    z-index: -1;
}

.hero-bg::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(ellipse at 30% 50%, rgba(27, 139, 78, 0.08) 0%, transparent 60%),
                radial-gradient(ellipse at 70% 30%, rgba(19, 43, 72, 0.3) 0%, transparent 60%);
}

.hero-content {
    position: relative;
    z-index: 1;
    padding: 120px 20px 80px;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: rgba(27, 139, 78, 0.15);
    border: 1px solid rgba(27, 139, 78, 0.3);
    color: #4ADE80;
    padding: 8px 20px;
    border-radius: 50px;
    font-size: 13px;
    font-weight: 600;
    margin-bottom: 30px;
    letter-spacing: 0.5px;
}

.hero-badge i {
    font-size: 14px;
}

.hero-title {
    font-size: clamp(32px, 5vw, 56px);
    font-weight: 800;
    color: var(--white);
    line-height: 1.2;
    margin-bottom: 20px;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.hero-subtitle {
    font-size: clamp(16px, 2vw, 20px);
    color: rgba(255, 255, 255, 0.7);
    max-width: 650px;
    margin: 0 auto 40px;
    line-height: 1.6;
}

.hero-btns {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 16px;
    margin-bottom: 60px;
    flex-wrap: wrap;
}

.hero-stats {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0;
    flex-wrap: wrap;
}

.stat-item {
    text-align: center;
    padding: 20px 30px;
}

.stat-number {
    font-size: 42px;
    font-weight: 800;
    color: var(--white);
    line-height: 1;
}

.stat-suffix {
    font-size: 28px;
    font-weight: 700;
    color: var(--primary);
}

.stat-label {
    display: block;
    font-size: 12px;
    font-weight: 600;
    color: rgba(255, 255, 255, 0.5);
    letter-spacing: 1.5px;
    margin-top: 8px;
    text-transform: uppercase;
}

.stat-divider {
    width: 1px;
    height: 50px;
    background: rgba(255, 255, 255, 0.15);
}

/* === Section Common === */
.section {
    padding: 100px 0;
}

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

.section-tag {
    display: inline-block;
    font-size: 13px;
    font-weight: 700;
    color: var(--primary);
    letter-spacing: 2px;
    text-transform: uppercase;
    margin-bottom: 12px;
    background: var(--primary-light);
    padding: 6px 16px;
    border-radius: 50px;
}

.section-title {
    font-size: clamp(28px, 3.5vw, 40px);
    font-weight: 800;
    color: var(--text-dark);
    margin-bottom: 16px;
}

.section-desc {
    font-size: 17px;
    color: var(--text-muted);
    max-width: 600px;
    margin: 0 auto;
    line-height: 1.7;
}

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

.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: start;
}

.about-text p {
    font-size: 16px;
    color: var(--text-muted);
    line-height: 1.8;
    margin-bottom: 20px;
}

.about-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 28px;
}

.tag {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background: var(--primary-light);
    color: var(--primary);
    padding: 8px 16px;
    border-radius: 50px;
    font-size: 13px;
    font-weight: 600;
}

.tag i {
    font-size: 12px;
}

.about-stats-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}

.about-stat-card {
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px 20px;
    text-align: center;
    transition: var(--transition);
}

.about-stat-card:hover {
    border-color: var(--primary);
    box-shadow: var(--shadow);
    transform: translateY(-4px);
}

.about-stat-icon {
    width: 48px;
    height: 48px;
    background: var(--primary-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 12px;
    color: var(--primary);
    font-size: 18px;
}

.about-stat-value {
    font-size: 36px;
    font-weight: 800;
    color: var(--text-dark);
}

.about-stat-value span {
    color: var(--primary);
}

.about-stat-desc {
    font-size: 13px;
    color: var(--text-muted);
    margin-top: 4px;
    font-weight: 500;
}

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

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

.service-card {
    background: var(--white);
    border-radius: var(--radius);
    padding: 36px;
    transition: var(--transition);
    border: 1px solid var(--border);
}

.service-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary);
}

.service-icon {
    width: 64px;
    height: 64px;
    background: var(--primary-light);
    border-radius: var(--radius);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
    font-size: 26px;
    color: var(--primary);
    transition: var(--transition);
}

.service-card:hover .service-icon {
    background: var(--primary);
    color: var(--white);
}

.service-card h3 {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text-dark);
}

.service-card p {
    font-size: 15px;
    color: var(--text-muted);
    line-height: 1.7;
    margin-bottom: 16px;
}

.service-features {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.service-features li {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 13px;
    color: var(--text-muted);
}

.service-features li i {
    color: var(--primary);
    font-size: 10px;
}

/* === Production Section === */
.production {
    background: var(--white);
}

.equipment-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
    margin-bottom: 60px;
}

.equipment-card {
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px 24px;
    text-align: center;
    transition: var(--transition);
}

.equipment-card:hover {
    border-color: var(--primary);
    box-shadow: var(--shadow);
    transform: translateY(-4px);
}

.equipment-icon {
    width: 56px;
    height: 56px;
    background: var(--primary-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 16px;
    font-size: 22px;
    color: var(--primary);
}

.equipment-card h4 {
    font-size: 15px;
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: 8px;
}

.equipment-card p {
    font-size: 13px;
    color: var(--text-muted);
    line-height: 1.6;
}

/* Process Flow */
.process-section {
    margin-bottom: 50px;
}

.process-title {
    text-align: center;
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 40px;
    color: var(--text-dark);
}

.process-flow {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0;
    flex-wrap: wrap;
}

.process-step {
    text-align: center;
    position: relative;
    padding: 0 12px;
}

.step-number {
    position: absolute;
    top: -8px;
    left: 50%;
    transform: translateX(-50%);
    width: 22px;
    height: 22px;
    background: var(--primary);
    color: var(--white);
    border-radius: 50%;
    font-size: 11px;
    font-weight: 700;
    display: flex;
    align-items: center;
    justify-content: center;
}

.step-icon {
    width: 64px;
    height: 64px;
    background: var(--primary-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 10px;
    font-size: 22px;
    color: var(--primary);
}

.process-step h5 {
    font-size: 12px;
    font-weight: 600;
    color: var(--text-dark);
    max-width: 100px;
    margin: 0 auto;
}

.process-arrow {
    color: var(--primary);
    font-size: 18px;
    padding: 0 4px;
}

/* Metrics */
.metrics-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
}

.metric-card {
    text-align: center;
    background: var(--primary-light);
    border-radius: var(--radius);
    padding: 30px 20px;
    transition: var(--transition);
}

.metric-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow);
}

.metric-value {
    font-size: 40px;
    font-weight: 800;
    color: var(--primary);
    line-height: 1;
}

.metric-value span {
    font-size: 24px;
}

.metric-label {
    font-size: 13px;
    color: var(--text-muted);
    margin-top: 8px;
    font-weight: 500;
}

/* === Quality Section === */
.quality {
    background: var(--bg-light);
}

.qc-process-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    margin-bottom: 60px;
}

.qc-card {
    background: var(--white);
    border-radius: var(--radius);
    padding: 36px 28px;
    position: relative;
    border: 1px solid var(--border);
    transition: var(--transition);
}

.qc-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary);
}

.qc-step {
    position: absolute;
    top: 16px;
    right: 20px;
    font-size: 40px;
    font-weight: 800;
    color: rgba(27, 139, 78, 0.08);
    line-height: 1;
}

.qc-icon {
    width: 56px;
    height: 56px;
    background: var(--primary-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 18px;
    font-size: 22px;
    color: var(--primary);
}

.qc-card h4 {
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text-dark);
}

.qc-card p {
    font-size: 14px;
    color: var(--text-muted);
    line-height: 1.7;
}

/* Test Equipment */
.test-equipment-section {
    margin-bottom: 50px;
}

.subsection-title {
    text-align: center;
    font-size: 22px;
    font-weight: 700;
    margin-bottom: 30px;
    color: var(--text-dark);
}

.test-equipment-grid {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 20px;
}

.test-item {
    display: flex;
    align-items: center;
    gap: 10px;
    background: var(--white);
    border: 1px solid var(--border);
    padding: 14px 24px;
    border-radius: 50px;
    transition: var(--transition);
}

.test-item:hover {
    border-color: var(--primary);
    background: var(--primary-light);
}

.test-item i {
    color: var(--primary);
    font-size: 18px;
}

.test-item span {
    font-size: 14px;
    font-weight: 600;
    color: var(--text-dark);
}

/* ISO Banner */
.iso-banner {
    display: flex;
    align-items: center;
    gap: 24px;
    background: linear-gradient(135deg, var(--primary), var(--primary-hover));
    border-radius: var(--radius);
    padding: 36px 40px;
    color: var(--white);
}

.iso-icon {
    font-size: 48px;
    opacity: 0.9;
    flex-shrink: 0;
}

.iso-text h4 {
    font-size: 22px;
    font-weight: 700;
    margin-bottom: 8px;
}

.iso-text p {
    font-size: 15px;
    opacity: 0.9;
    line-height: 1.6;
}

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

.products-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
}

.product-card {
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 32px 20px;
    text-align: center;
    transition: var(--transition);
}

.product-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary);
}

.product-icon {
    width: 64px;
    height: 64px;
    background: var(--primary-light);
    border-radius: var(--radius);
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 16px;
    font-size: 26px;
    color: var(--primary);
    transition: var(--transition);
}

.product-card:hover .product-icon {
    background: var(--primary);
    color: var(--white);
}

.product-card h4 {
    font-size: 16px;
    font-weight: 700;
    margin-bottom: 8px;
    color: var(--text-dark);
}

.product-card p {
    font-size: 13px;
    color: var(--text-muted);
    line-height: 1.5;
}

/* === Partners Section === */
.partners {
    background: var(--bg-light);
}

.partners-grid {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 24px;
}

.partner-card {
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px 16px;
    text-align: center;
    transition: var(--transition);
}

.partner-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow);
    border-color: var(--primary);
}

.partner-logo {
    width: 48px;
    height: 48px;
    background: var(--primary-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 12px;
    font-size: 20px;
    color: var(--primary);
}

.partner-card span {
    font-size: 15px;
    font-weight: 700;
    color: var(--text-dark);
    display: block;
    margin-bottom: 4px;
}

.partner-card small {
    font-size: 12px;
    color: var(--text-muted);
}

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

.contact-grid {
    display: grid;
    grid-template-columns: 1.2fr 1fr;
    gap: 50px;
}

.contact-form-wrapper {
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 36px;
}

.contact-form .form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    font-size: 14px;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 6px;
}

.required {
    color: #e53e3e;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    font-family: 'Inter', sans-serif;
    font-size: 14px;
    color: var(--text-dark);
    transition: var(--transition);
    background: var(--white);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(27, 139, 78, 0.1);
}

.form-group input.error,
.form-group select.error,
.form-group textarea.error {
    border-color: #e53e3e;
}

.form-group .error-msg {
    display: none;
    font-size: 12px;
    color: #e53e3e;
    margin-top: 4px;
}

.form-group .error-msg.show {
    display: block;
}

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

.form-group select {
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%23666' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 14px center;
    padding-right: 40px;
}

.form-success {
    display: none;
    align-items: center;
    gap: 10px;
    padding: 14px 20px;
    background: var(--primary-light);
    color: var(--primary);
    border-radius: var(--radius-sm);
    margin-top: 16px;
    font-size: 14px;
    font-weight: 500;
}

.form-success.show {
    display: flex;
}

.form-success i {
    font-size: 18px;
}

/* Contact Info */
.contact-info {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.info-card {
    background: var(--bg-light);
    border-radius: var(--radius);
    padding: 28px;
}

.info-item {
    display: flex;
    align-items: flex-start;
    gap: 16px;
    padding: 14px 0;
}

.info-item + .info-item {
    border-top: 1px solid var(--border);
}

.info-icon {
    width: 42px;
    height: 42px;
    background: var(--primary-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--primary);
    font-size: 16px;
    flex-shrink: 0;
}

.info-item h5 {
    font-size: 13px;
    font-weight: 600;
    color: var(--text-muted);
    margin-bottom: 2px;
}

.info-item p {
    font-size: 15px;
    font-weight: 500;
    color: var(--text-dark);
}

.map-wrapper {
    border-radius: var(--radius);
    overflow: hidden;
    border: 1px solid var(--border);
}

.map-wrapper iframe {
    display: block;
}

/* === Footer === */
.footer {
    background: var(--bg-dark);
    padding: 70px 0 0;
    color: rgba(255, 255, 255, 0.7);
}

.footer-grid {
    display: grid;
    grid-template-columns: 1.5fr 1fr 1fr 1.2fr;
    gap: 40px;
    padding-bottom: 40px;
}

.footer-logo {
    font-size: 22px;
    font-weight: 800;
    margin-bottom: 16px;
    display: inline-block;
}

.footer-logo .logo-one {
    color: var(--white);
}

.footer-brand p {
    font-size: 14px;
    line-height: 1.7;
    margin-bottom: 20px;
}

.social-links {
    display: flex;
    gap: 12px;
}

.social-links a {
    width: 36px;
    height: 36px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: rgba(255, 255, 255, 0.7);
    font-size: 14px;
    transition: var(--transition);
}

.social-links a:hover {
    background: var(--primary);
    color: var(--white);
}

.footer-col h4 {
    color: var(--white);
    font-size: 16px;
    font-weight: 700;
    margin-bottom: 20px;
}

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

.footer-col ul li a {
    font-size: 14px;
    color: rgba(255, 255, 255, 0.6);
    transition: var(--transition);
}

.footer-col ul li a:hover {
    color: var(--primary);
    padding-left: 4px;
}

.footer-contact li {
    display: flex;
    align-items: center;
    gap: 10px;
}

.footer-contact li i {
    color: var(--primary);
    font-size: 14px;
    width: 16px;
}

.footer-contact li span {
    font-size: 14px;
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding: 20px 0;
    text-align: center;
    font-size: 13px;
}

/* === Back to Top === */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 44px;
    height: 44px;
    background: var(--primary);
    color: var(--white);
    border: none;
    border-radius: 50%;
    font-size: 16px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: var(--transition);
    box-shadow: 0 4px 12px rgba(27, 139, 78, 0.3);
    z-index: 999;
}

.back-to-top.show {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    background: var(--primary-hover);
    transform: translateY(-4px);
}

/* === Responsive Design === */
@media (max-width: 1024px) {
    .about-grid {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .services-grid {
        grid-template-columns: 1fr 1fr;
    }

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

    .products-grid {
        grid-template-columns: repeat(3, 1fr);
    }

    .partners-grid {
        grid-template-columns: repeat(3, 1fr);
    }

    .footer-grid {
        grid-template-columns: 1fr 1fr;
        gap: 30px;
    }
}

@media (max-width: 768px) {
    .section {
        padding: 70px 0;
    }

    .nav-links {
        position: fixed;
        top: 0;
        right: -100%;
        width: 280px;
        height: 100vh;
        background: var(--white);
        flex-direction: column;
        align-items: flex-start;
        padding: 80px 30px 30px;
        gap: 0;
        box-shadow: var(--shadow-lg);
        transition: var(--transition);
        z-index: 999;
    }

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

    .nav-links a {
        color: var(--text-dark) !important;
        padding: 12px 0;
        width: 100%;
        border-bottom: 1px solid var(--border);
    }

    .mobile-toggle {
        display: flex;
    }

    .nav-cta {
        display: none;
    }

    .hero-stats {
        flex-wrap: wrap;
    }

    .stat-divider {
        display: none;
    }

    .stat-item {
        padding: 12px 20px;
    }

    .stat-number {
        font-size: 32px;
    }

    .services-grid {
        grid-template-columns: 1fr;
    }

    .equipment-grid {
        grid-template-columns: 1fr 1fr;
    }

    .process-flow {
        flex-direction: column;
        gap: 12px;
    }

    .process-arrow {
        transform: rotate(90deg);
    }

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

    .qc-process-grid {
        grid-template-columns: 1fr;
    }

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

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

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

    .contact-form .form-row {
        grid-template-columns: 1fr;
    }

    .iso-banner {
        flex-direction: column;
        text-align: center;
    }

    .footer-grid {
        grid-template-columns: 1fr;
        gap: 30px;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 28px;
    }

    .hero-btns {
        flex-direction: column;
    }

    .hero-btns .btn {
        width: 100%;
    }

    .equipment-grid {
        grid-template-columns: 1fr;
    }

    .products-grid {
        grid-template-columns: 1fr;
    }

    .partners-grid {
        grid-template-columns: 1fr 1fr;
    }

    .metrics-grid {
        grid-template-columns: 1fr 1fr;
    }

    .stat-item {
        width: 50%;
    }

    .about-stats-grid {