/* ============================================================
   阿拉充电 - 绿荫物琏科技（杭州）有限公司 官方网站
   主题：绿色能源 / 科技感
   ============================================================ */

/* --- CSS Variables --- */
:root {
    --color-primary: #1677FF;
    --color-primary-dark: #0958D9;
    --color-primary-light: #4096FF;
    --color-primary-bg: #E6F0FF;
    --color-accent: #FF6B35;
    --color-dark: #1A1A2E;
    --color-dark-secondary: #16213E;
    --color-gray-900: #212529;
    --color-gray-700: #495057;
    --color-gray-500: #6C757D;
    --color-gray-300: #CED4DA;
    --color-gray-100: #F1F3F5;
    --color-white: #FFFFFF;
    --color-bg: #FAFBFD;

    --font-family: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', Arial, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 2rem;
    --font-size-4xl: 2.5rem;
    --font-size-5xl: 3.5rem;

    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-xl: 28px;

    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.10);
    --shadow-xl: 0 16px 60px rgba(0, 0, 0, 0.12);

    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 0.5s cubic-bezier(0.4, 0, 0.2, 1);

    --header-height: 72px;
    --max-width: 1200px;
}

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

html {
    scroll-behavior: smooth;
    scroll-padding-top: var(--header-height);
    font-size: 16px;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.7;
    color: var(--color-gray-700);
    background: var(--color-white);
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

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

ul { list-style: none; }
img { max-width: 100%; display: block; }

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
}

/* --- Header --- */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    height: var(--header-height);
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid transparent;
    transition: all var(--transition);
}

.header.scrolled {
    border-bottom-color: rgba(0, 0, 0, 0.06);
    box-shadow: var(--shadow-sm);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: var(--font-size-2xl);
    font-weight: 800;
    color: var(--color-dark);
}

.logo-icon {
    font-size: 1.8rem;
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.15); }
}

.logo-text {
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-list {
    display: flex;
    align-items: center;
    gap: 36px;
}

.nav-link {
    position: relative;
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--color-gray-700);
    padding: 8px 0;
    transition: color var(--transition);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%) scaleX(0);
    width: 100%;
    height: 2px;
    background: var(--color-primary);
    border-radius: 1px;
    transition: transform var(--transition);
}

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

.nav-link:hover::after,
.nav-link.active::after {
    transform: translateX(-50%) scaleX(1);
}

.menu-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
    z-index: 1001;
}

.menu-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--color-dark);
    border-radius: 2px;
    transition: all var(--transition);
}

.menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

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

.menu-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

/* --- Hero Section --- */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(160deg, #F0F5FF 0%, #E6F0FF 25%, #F5F8FC 60%, #EEF2FA 100%);
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background:
        radial-gradient(ellipse at 20% 80%, rgba(22, 119, 255, 0.06) 0%, transparent 50%),
        radial-gradient(ellipse at 75% 20%, rgba(22, 119, 255, 0.04) 0%, transparent 50%),
        radial-gradient(ellipse at 50% 50%, rgba(64, 150, 255, 0.03) 0%, transparent 60%);
    animation: heroBg 20s ease-in-out infinite;
}

@keyframes heroBg {
    0%, 100% { transform: translate(0, 0) rotate(0deg); }
    33% { transform: translate(1%, -1%) rotate(1deg); }
    66% { transform: translate(-1%, 1%) rotate(-1deg); }
}

.hero::after {
    content: '';
    position: absolute;
    inset: 0;
    background:
        repeating-linear-gradient(0deg, transparent, transparent 2px, rgba(22, 119, 255, 0.012) 2px, rgba(22, 119, 255, 0.012) 4px),
        repeating-linear-gradient(90deg, transparent, transparent 40px, rgba(22, 119, 255, 0.015) 40px, rgba(22, 119, 255, 0.015) 42px);
    pointer-events: none;
}

.hero-overlay {
    display: none;
}

.hero-content {
    position: relative;
    z-index: 2;
    text-align: center;
    color: var(--color-dark);
    padding: 120px 0 80px;
    width: 100%;
}

.hero-title {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-bottom: 28px;
}

.hero-brand {
    font-size: clamp(2.5rem, 6vw, var(--font-size-5xl));
    font-weight: 900;
    letter-spacing: 0.04em;
    background: linear-gradient(135deg, #69B1FF 0%, var(--color-primary) 40%, #4096FF 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    filter: drop-shadow(0 0 30px rgba(22, 119, 255, 0.4));
    animation: brandGlow 3s ease-in-out infinite;
}

@keyframes brandGlow {
    0%, 100% { filter: drop-shadow(0 0 30px rgba(22, 119, 255, 0.3)); }
    50% { filter: drop-shadow(0 0 50px rgba(22, 119, 255, 0.6)); }
}

.hero-subtitle {
    font-size: clamp(1.25rem, 2.5vw, var(--font-size-2xl));
    font-weight: 300;
    color: var(--color-gray-500);
    letter-spacing: 0.08em;
}

.hero-desc {
    font-size: var(--font-size-lg);
    line-height: 2;
    color: var(--color-gray-500);
    margin-bottom: 42px;
}

.hero-btns {
    display: flex;
    gap: 18px;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 64px;
}

/* --- Buttons --- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 14px 36px;
    border-radius: 50px;
    font-size: var(--font-size-base);
    font-weight: 600;
    border: none;
    cursor: pointer;
    transition: all var(--transition);
    white-space: nowrap;
}

.btn-primary {
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
    color: var(--color-white);
    box-shadow: 0 4px 20px rgba(22, 119, 255, 0.35);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(22, 119, 255, 0.5);
    background: linear-gradient(135deg, var(--color-primary-light), var(--color-primary));
}

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

.btn-outline:hover {
    border-color: var(--color-primary-dark);
    color: var(--color-primary-dark);
    background: rgba(22, 119, 255, 0.06);
}

/* --- Hero Stats --- */
.hero-stats {
    display: flex;
    justify-content: center;
    gap: clamp(32px, 8vw, 80px);
    flex-wrap: wrap;
}

.stat-item {
    text-align: center;
}

.stat-number {
    display: block;
    font-size: var(--font-size-4xl);
    font-weight: 800;
    color: var(--color-primary);
    line-height: 1.2;
}

.stat-label {
    font-size: var(--font-size-sm);
    color: var(--color-gray-500);
    text-transform: uppercase;
    letter-spacing: 0.06em;
}

/* --- Hero Scroll Indicator --- */
.hero-scroll {
    position: absolute;
    bottom: 32px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 2;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    color: var(--color-gray-300);
    font-size: var(--font-size-xs);
    letter-spacing: 0.1em;
    animation: bounce 2s ease-in-out infinite;
}

@keyframes bounce {
    0%, 100% { transform: translateX(-50%) translateY(0); }
    50% { transform: translateX(-50%) translateY(-8px); }
}

.scroll-arrow {
    width: 1px;
    height: 24px;
    background: linear-gradient(180deg, var(--color-gray-300), transparent);
}

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

.section:nth-child(even) {
    background: var(--color-bg);
}

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

.section-title {
    font-size: var(--font-size-3xl);
    font-weight: 800;
    color: var(--color-dark);
    margin-bottom: 12px;
    position: relative;
    display: inline-block;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 50%;
    transform: translateX(-50%);
    width: 50px;
    height: 4px;
    background: linear-gradient(90deg, var(--color-primary), var(--color-primary-light));
    border-radius: 2px;
}

.section-subtitle {
    font-size: var(--font-size-lg);
    color: var(--color-gray-500);
    margin-top: 18px;
}

/* --- About Section --- */
.about-grid {
    display: grid;
    grid-template-columns: 1.1fr 0.9fr;
    gap: 64px;
    align-items: center;
}

.about-text h3 {
    font-size: var(--font-size-2xl);
    color: var(--color-dark);
    margin-bottom: 20px;
}

.about-text p {
    margin-bottom: 16px;
    line-height: 1.9;
    color: var(--color-gray-700);
}

.about-text p:last-of-type {
    margin-bottom: 28px;
}

.about-badges {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 14px;
}

.badge {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 12px 18px;
    background: var(--color-white);
    border: 1px solid var(--color-gray-300);
    border-radius: var(--radius-sm);
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--color-dark);
    transition: all var(--transition);
}

.badge:hover {
    border-color: var(--color-primary);
    box-shadow: 0 2px 12px rgba(22, 119, 255, 0.1);
    transform: translateY(-1px);
}

.badge-icon {
    font-size: 1.3rem;
}

.about-image {
    display: flex;
    align-items: center;
    justify-content: center;
}

.about-img-placeholder {
    width: 100%;
    /* aspect-ratio: 4 / 3; */
    background: linear-gradient(135deg, var(--color-primary-bg), #D6E4FF);
    border-radius: var(--radius-lg);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 8px;
    color: var(--color-primary);
    /* border: 2px dashed rgba(22, 119, 255, 0.3); */
}

.img-icon {
    font-size: 4rem;
    opacity: 0.9;
	border-radius: var(--radius-lg);
}

.about-img-placeholder span {
    font-size: var(--font-size-sm);
    opacity: 0.6;
}

/* --- Products Section --- */
.products {
    background: var(--color-bg);
}

.product-tabs {
    display: flex;
    justify-content: center;
    gap: 12px;
    margin-bottom: 48px;
    flex-wrap: wrap;
}

.tab-btn {
    padding: 12px 28px;
    border: 2px solid var(--color-gray-300);
    background: var(--color-white);
    color: var(--color-gray-700);
    border-radius: 50px;
    font-size: var(--font-size-sm);
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition);
}

.tab-btn:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
}

.tab-btn.active {
    background: var(--color-primary);
    border-color: var(--color-primary);
    color: var(--color-white);
    box-shadow: 0 4px 16px rgba(22, 119, 255, 0.3);
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
    animation: fadeInUp 0.5s ease;
}

@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.product-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 28px;
}

.product-card {
    background: var(--color-white);
    border-radius: var(--radius-md);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-slow);
    border: 1px solid var(--color-gray-100);
}

.product-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
    border-color: rgba(22, 119, 255, 0.15);
}

.product-img {
    height: 200px;
    /* background: linear-gradient(135deg, #0A1F1A 0%, #0D2E25 100%); */
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 8px;
    position: relative;
    overflow: hidden;
}

.product-img::before {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at 50% 30%, rgba(22, 119, 255, 0.2), transparent 70%);
}

.product-img-icon {
    font-size: 3.5rem;
    position: relative;
    z-index: 1;
}

.product-tag {
    position: absolute;
    top: 16px;
    right: 16px;
    background: var(--color-primary);
    color: var(--color-white);
    padding: 4px 14px;
    border-radius: 50px;
    font-size: var(--font-size-xs);
    font-weight: 600;
}

.product-info {
    padding: 24px;
}

.product-info h4 {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-dark);
    margin-bottom: 10px;
}

.product-info p {
    font-size: var(--font-size-sm);
    color: var(--color-gray-500);
    margin-bottom: 16px;
    line-height: 1.6;
}

.product-specs {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.product-specs li {
    font-size: var(--font-size-xs);
    color: var(--color-gray-700);
    background: var(--color-bg);
    padding: 5px 12px;
    border-radius: 50px;
    white-space: nowrap;
    transition: all var(--transition);
}

.product-specs li:hover {
    background: var(--color-primary-bg);
    color: var(--color-primary-dark);
}

/* --- Features Section --- */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 28px;
}

.feature-card {
    background: var(--color-white);
    border-radius: var(--radius-md);
    padding: 36px 28px;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-gray-100);
    transition: all var(--transition-slow);
    text-align: center;
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: rgba(22, 119, 255, 0.2);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: 18px;
    display: block;
}

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

.feature-card p {
    font-size: var(--font-size-sm);
    color: var(--color-gray-500);
    line-height: 1.8;
}

/* --- Scenarios Section --- */
.scenarios {
    background: var(--color-white);
}

.scenarios-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
}

.scenario-card {
    background: var(--color-bg);
    border-radius: var(--radius-md);
    padding: 32px 24px;
    text-align: center;
    transition: all var(--transition-slow);
    border: 1px solid transparent;
}

.scenario-card:hover {
    background: var(--color-white);
    border-color: rgba(22, 119, 255, 0.15);
    box-shadow: var(--shadow-md);
    transform: translateY(-4px);
}

.scenario-img {
    margin-bottom: 18px;
}

.scenario-icon {
    font-size: 3rem;
    display: inline-block;
    transition: transform var(--transition);
}

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

.scenario-card h4 {
    font-size: var(--font-size-lg);
    font-weight: 700;
    color: var(--color-dark);
    margin-bottom: 10px;
}

.scenario-card p {
    font-size: var(--font-size-sm);
    color: var(--color-gray-500);
    line-height: 1.7;
}

/* --- Honor / Trust Section --- */
.trust {
    background: linear-gradient(180deg, var(--color-white) 0%, var(--color-primary-bg) 100%);
}

/* Honor Gallery */
.honor-gallery {
    display: flex;
    justify-content: center;
    gap: 24px;
    flex-wrap: nowrap;
    overflow-x: auto;
    padding-bottom: 8px;
}

.honor-item {
    text-align: center;
    flex: 1 1 0;
    min-width: 160px;
}

.honor-img {
    background: var(--color-white);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-md);
    overflow: hidden;
    transition: all var(--transition-slow);
    height: 260px;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 10px;
}

.honor-img img {
    height: 100%;
    width: auto;
    max-width: 100%;
    object-fit: contain;
    display: block;
}

.honor-item:hover .honor-img {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
}

.honor-item h4 {
    margin-top: 14px;
    font-size: var(--font-size-sm);
    font-weight: 600;
    color: var(--color-dark);
}

/* --- Cases Section --- */
.cases {
    background: var(--color-bg);
}

.cases-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
    margin-bottom: 48px;
}

.case-card {
    background: var(--color-white);
    border-radius: var(--radius-md);
	overflow: hidden;
    text-align: center;
    transition: all var(--transition-slow);
    border: 1px solid var(--color-gray-100);
    box-shadow: var(--shadow-sm);
	display: flex;
	flex-direction: column;
}

.case-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: rgba(22, 119, 255, 0.2);
}

.case-icon {
	width: 100%;
	height: 220px;
	overflow: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
}

.case-icon img {
	width: 100%;
	height: 100%;
	object-fit: cover;
    display: block;
	transition: transform var(--transition-slow);
}

	.case-card:hover .case-icon img {
	transform: scale(1.08);
}

.case-card h4 {
    font-size: var(--font-size-lg);
    font-weight: 700;
    color: var(--color-dark);
    margin: 20px 24px 8px;
}

.case-card p {
    font-size: var(--font-size-sm);
    color: var(--color-gray-500);
    line-height: 1.7;
	margin: 0 24px 24px;
}

.cases-action {
    text-align: center;
}

.cases-action p {
    font-size: var(--font-size-base);
    color: var(--color-gray-500);
    margin-bottom: 20px;
}

/* --- Contact Section --- */
.contact-grid {
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 48px;
    align-items: start;
}

.contact-info h3 {
    font-size: var(--font-size-2xl);
    color: var(--color-dark);
    margin-bottom: 28px;
}

.contact-items {
    display: flex;
    flex-direction: column;
    gap: 22px;
}

.contact-item {
    display: flex;
    gap: 16px;
    align-items: flex-start;
}

.contact-icon {
    font-size: 1.5rem;
    flex-shrink: 0;
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--color-primary-bg);
    border-radius: var(--radius-sm);
}

.contact-item strong {
    display: block;
    font-size: var(--font-size-sm);
    color: var(--color-dark);
    margin-bottom: 2px;
}

.contact-item p {
    font-size: var(--font-size-base);
    color: var(--color-gray-500);
}

.contact-qr {
    display: flex;
    justify-content: center;
}

.qr-card {
    text-align: center;
    padding: 32px;
    background: var(--color-white);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--color-gray-100);
}

.qr-placeholder {
    width: 160px;
    height: 160px;
    margin: 0 auto 16px;
    background: var(--color-bg);
    border: 2px dashed var(--color-gray-300);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--font-size-2xl);
    font-weight: 700;
    color: var(--color-gray-300);
}

.qr-card p {
    font-weight: 600;
    color: var(--color-dark);
    margin-bottom: 4px;
}

.qr-tip {
    font-size: var(--font-size-xs);
    color: var(--color-gray-500);
}

/* --- Footer --- */
.footer {
    background: var(--color-dark-secondary);
    color: rgba(255, 255, 255, 0.7);
    padding-top: 64px;
}

.footer-main {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 48px;
    padding-bottom: 40px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.footer-logo {
    font-size: var(--font-size-2xl);
    font-weight: 800;
    color: var(--color-white);
    display: inline-flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 12px;
}

.footer-brand p {
    font-size: var(--font-size-sm);
    color: rgba(255, 255, 255, 0.5);
    line-height: 1.6;
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
}

.footer-col h4 {
    font-size: var(--font-size-base);
    font-weight: 600;
    color: var(--color-white);
    margin-bottom: 16px;
}

.footer-col ul li {
    margin-bottom: 10px;
    font-size: var(--font-size-sm);
    color: rgba(255, 255, 255, 0.55);
}

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

.footer-bottom {
    text-align: center;
    padding: 24px 0;
    font-size: var(--font-size-xs);
    color: rgba(255, 255, 255, 0.4);
    line-height: 1.8;
}

.footer-bottom a {
    color: rgba(255, 255, 255, 0.4);
    transition: color var(--transition);
}

.footer-bottom a:hover {
    color: var(--color-primary-light);
}

/* --- Back to Top --- */
.back-to-top {
    position: fixed;
    bottom: 32px;
    right: 32px;
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: var(--color-primary);
    color: var(--color-white);
    border: none;
    cursor: pointer;
    font-size: 1.4rem;
    box-shadow: var(--shadow-md);
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: all var(--transition);
    z-index: 999;
    display: flex;
    align-items: center;
    justify-content: center;
}

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

.back-to-top:hover {
    background: var(--color-primary-dark);
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

/* --- Responsive Design --- */

/* Tablet */
@media (max-width: 992px) {
    :root {
        --header-height: 64px;
    }

    .section {
        padding: 72px 0;
    }

    .section-title {
        font-size: var(--font-size-2xl);
    }

    .about-grid {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .about-image {
        order: -1;
    }

    .about-img-placeholder {
        max-width: 480px;
        margin: 0 auto;
    }

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

    .contact-qr {
        order: -1;
    }

    .footer-main {
        grid-template-columns: 1fr;
        gap: 36px;
    }

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

    .hero-stats {
        gap: 36px;
    }

    .stat-number {
        font-size: var(--font-size-3xl);
    }
}

/* Mobile */
@media (max-width: 768px) {
    .menu-toggle {
        display: flex;
    }

    .nav {
        position: fixed;
        top: 0;
        right: -100%;
        width: 280px;
        height: 100vh;
        background: var(--color-white);
        box-shadow: var(--shadow-xl);
        transition: right var(--transition-slow);
        padding: 100px 28px 40px;
        z-index: 1000;
    }

    .nav.active {
        right: 0;
    }

    .nav-list {
        flex-direction: column;
        gap: 8px;
        align-items: stretch;
    }

    .nav-link {
        display: block;
        padding: 12px 16px;
        border-radius: var(--radius-sm);
        font-size: var(--font-size-base);
    }

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

    .nav-link::after {
        display: none;
    }

    .hero {
        min-height: auto;
    }

    .hero-content {
        padding: 140px 0 60px;
    }

    .hero-brand {
        font-size: 2.2rem;
    }

    .hero-subtitle {
        font-size: 1.1rem;
    }

    .hero-desc {
        font-size: var(--font-size-sm);
        line-height: 1.8;
    }

    .hero-stats {
        gap: 24px;
    }

    .stat-number {
        font-size: var(--font-size-2xl);
    }

    .section {
        padding: 56px 0;
    }

    .section-title {
        font-size: var(--font-size-2xl);
    }

    .product-grid,
    .features-grid,
    .scenarios-grid {
        grid-template-columns: 1fr;
    }

    .about-badges {
        grid-template-columns: 1fr 1fr;
        gap: 10px;
    }

    .badge {
        padding: 10px 14px;
        font-size: var(--font-size-xs);
    }

    .honor-gallery {
        gap: 14px;
    }

    .honor-item {
        min-width: 120px;
    }

    .honor-img {
        height: 200px;
        padding: 6px;
    }

    .honor-item h4 {
        font-size: var(--font-size-xs);
    }

    .footer-links {
        grid-template-columns: 1fr;
        gap: 24px;
    }

    .back-to-top {
        bottom: 20px;
        right: 20px;
        width: 40px;
        height: 40px;
        font-size: 1.2rem;
    }
}

/* Small Mobile */
@media (max-width: 480px) {
    .container {
        padding: 0 16px;
    }

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

    .btn {
        width: 100%;
        max-width: 280px;
    }

    .about-badges {
        grid-template-columns: 1fr;
    }

    .honor-gallery {
        gap: 10px;
    }

    .honor-item {
        min-width: 90px;
    }

    .honor-img {
        height: 160px;
        padding: 4px;
    }

    .honor-item h4 {
        font-size: 0.65rem;
        margin-top: 8px;
    }

    .product-tabs {
        gap: 8px;
    }

    .tab-btn {
        padding: 10px 20px;
        font-size: var(--font-size-xs);
    }
}

/* --- Dark overlay when mobile nav open --- */
.nav-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    z-index: 999;
}

.nav-overlay.active {
    display: block;
}

.CompanyCertificatesSection .certificates-grid .cert-item .cert-image {
    max-width: 100%;
    aspect-ratio: 1 / 1;
    object-fit: contain;
    flex-shrink: 0;
}
img {
    max-width: 100%;
    border: 0;
    vertical-align: middle;
}