/* ====== CSS Variables ====== */
:root {
    --primary: #d97706;
    --primary-dark: #b45309;
    --primary-light: #fef3c7;
    --primary-gradient: linear-gradient(135deg, #d97706, #f59e0b, #fbbf24);
    --accent: #f59e0b;
    --accent-light: #fffbeb;
    --dark: #171717;
    --gray-900: #262626;
    --gray-700: #404040;
    --gray-500: #737373;
    --gray-300: #d4d4d4;
    --gray-100: #fafaf9;
    --white: #ffffff;
    --radius-sm: 6px;
    --radius: 10px;
    --radius-lg: 16px;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.06);
    --shadow: 0 4px 24px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 8px 40px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 16px 60px rgba(0, 0, 0, 0.1);
    --transition: all 0.35s cubic-bezier(0.4, 0, 0.2, 1);
}

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

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", "Noto Sans SC", "Helvetica Neue", Arial, sans-serif;
    color: var(--gray-700);
    line-height: 1.75;
    font-size: 15px;
    overflow-x: hidden;
    background: var(--white);
    -webkit-font-smoothing: antialiased;
}

a { text-decoration: none; color: inherit; }
ul { list-style: none; }
img { max-width: 100%; height: auto; display: block; }

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

/* ====== Buttons ====== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: clamp(10px, 1.2vw, 13px) clamp(24px, 3.5vw, 36px);
    border-radius: 8px;
    font-size: clamp(13px, 1.3vw, 15px);
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    border: 2px solid transparent;
    text-align: center;
    letter-spacing: 0.3px;
    position: relative;
    overflow: hidden;
}

.btn::after {
    content: '';
    position: absolute;
    inset: 0;
    background: rgba(255,255,255,0.15);
    opacity: 0;
    transition: opacity 0.3s;
}

.btn:hover::after { opacity: 1; }

.btn-primary {
    background: var(--primary-gradient);
    color: #fff;
    border-color: transparent;
    box-shadow: 0 4px 16px rgba(217, 119, 6, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 28px rgba(217, 119, 6, 0.4);
}

.btn-outline {
    background: transparent;
    color: #fff;
    border-color: rgba(255, 255, 255, 0.5);
    backdrop-filter: blur(4px);
}

.btn-outline:hover {
    background: #fff;
    color: var(--primary);
    border-color: #fff;
    transform: translateY(-2px);
    box-shadow: 0 8px 28px rgba(0, 0, 0, 0.15);
}

.btn-block { width: 100%; }

/* ====== Header ====== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(16px) saturate(180%);
    -webkit-backdrop-filter: blur(16px) saturate(180%);
    border-bottom: 1px solid rgba(0,0,0,0.04);
    transition: var(--transition);
}

.header.scrolled {
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.06);
}

.header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 72px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 15px;
    font-weight: 700;
    color: var(--dark);
    white-space: nowrap;
    letter-spacing: 0.3px;
}

.logo img { height: 38px; width: auto; }

.nav ul {
    display: flex;
    gap: 8px;
}

.nav-link {
    font-size: 13.5px;
    font-weight: 500;
    color: var(--gray-500);
    transition: var(--transition);
    padding: 8px 16px;
    border-radius: 6px;
    letter-spacing: 0.3px;
}

.nav-link:hover {
    color: var(--primary);
    background: var(--primary-light);
}

.nav-link.active {
    color: var(--primary);
    background: var(--primary-light);
    font-weight: 600;
}

/* Mobile menu toggle */
.menu-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    background: none;
    border: none;
    padding: 6px;
    z-index: 1001;
}

.menu-toggle span {
    display: block;
    width: 24px;
    height: 2.5px;
    background: var(--gray-700);
    border-radius: 3px;
    transition: 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: clamp(450px, 100vh, 900px);
    background: linear-gradient(160deg, #171717 0%, #262626 30%, #292524 60%, #b45309 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: clamp(-40%, -15vw, -10%);
    right: clamp(-30%, -10vw, -5%);
    width: clamp(300px, 55vw, 700px);
    height: clamp(300px, 55vw, 700px);
    background: radial-gradient(circle, rgba(245, 158, 11, 0.15) 0%, transparent 70%);
    border-radius: 50%;
    animation: floatUpDown 10s ease-in-out infinite;
}

.hero::after {
    content: '';
    position: absolute;
    bottom: clamp(-30%, -12vw, -5%);
    left: clamp(-25%, -8vw, -5%);
    width: clamp(200px, 38vw, 500px);
    height: clamp(200px, 38vw, 500px);
    background: radial-gradient(circle, rgba(217, 119, 6, 0.12) 0%, transparent 70%);
    border-radius: 50%;
    animation: floatUpDown 8s ease-in-out infinite reverse;
}

@keyframes floatUpDown {
    0%, 100% { transform: translateY(0) scale(1); }
    50% { transform: translateY(clamp(-40px, -3vw, -15px)) scale(1.05); }
}

.hero-overlay {
    position: absolute;
    inset: 0;
    background-image: 
        radial-gradient(circle at 25% 25%, rgba(255,255,255,0.03) 1px, transparent 1px),
        radial-gradient(circle at 75% 75%, rgba(255,255,255,0.03) 1px, transparent 1px);
    background-size: clamp(30px, 5vw, 60px) clamp(30px, 5vw, 60px),
                     clamp(40px, 6.5vw, 80px) clamp(40px, 6.5vw, 80px);
    opacity: 0.6;
}

.hero-content {
    position: relative;
    z-index: 1;
    max-width: clamp(320px, 90vw, 880px);
    padding: 0 clamp(16px, 2.5vw, 24px);
}

.hero-badge {
    display: inline-block;
    padding: clamp(4px, 0.5vw, 6px) clamp(12px, 1.5vw, 16px);
    background: rgba(255, 255, 255, 0.08);
    border: 1px solid rgba(255, 255, 255, 0.12);
    border-radius: 50px;
    color: rgba(255, 255, 255, 0.8);
    font-size: clamp(11px, 1.2vw, 13px);
    font-weight: 500;
    margin-bottom: clamp(18px, 2.5vw, 28px);
    animation: fadeInUp 0.8s ease;
    backdrop-filter: blur(8px);
}

.hero-logo {
    margin-bottom: clamp(20px, 3vw, 32px);
    animation: fadeInUp 0.8s ease 0.1s both;
}

.hero-logo img {
    height: clamp(48px, 7vw, 72px);
    width: auto;
    margin: 0 auto;
    filter: drop-shadow(0 4px 20px rgba(255,255,255,0.15));
}

.hero-title {
    font-size: clamp(24px, 4.5vw, 44px);
    font-weight: 800;
    color: #fff;
    margin-bottom: clamp(12px, 1.8vw, 20px);
    letter-spacing: clamp(0.3px, 0.08vw, 1px);
    line-height: 1.2;
    white-space: nowrap;
    animation: fadeInUp 0.8s ease 0.2s both;
    background: linear-gradient(135deg, #ffffff 0%, #fef3c7 50%, #fbbf24 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: clamp(14px, 1.5vw, 18px);
    color: rgba(255, 255, 255, 0.7);
    margin-bottom: clamp(28px, 4vw, 44px);
    line-height: 1.7;
    animation: fadeInUp 0.8s ease 0.3s both;
    font-weight: 400;
}

.hero-buttons {
    display: flex;
    gap: clamp(10px, 1.5vw, 16px);
    justify-content: center;
    flex-wrap: wrap;
    animation: fadeInUp 0.8s ease 0.4s both;
}

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

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

.section-header {
    text-align: center;
    margin-bottom: 64px;
}

.section-tag {
    display: inline-block;
    padding: 4px 14px;
    background: var(--primary-light);
    color: var(--primary);
    font-size: 12px;
    font-weight: 700;
    border-radius: 50px;
    letter-spacing: 1.5px;
    text-transform: uppercase;
    margin-bottom: 16px;
}

.section-title {
    font-size: 36px;
    font-weight: 800;
    color: var(--dark);
    margin-bottom: 12px;
    letter-spacing: -0.5px;
    line-height: 1.3;
}

.section-desc {
    font-size: 16px;
    color: var(--gray-500);
    max-width: 560px;
    margin: 0 auto;
}

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

.about-grid {
    max-width: 800px;
    margin: 0 auto;
}

.about-text p {
    margin-bottom: 22px;
    font-size: 15.5px;
    color: var(--gray-500);
    line-height: 1.9;
    padding-left: 20px;
    border-left: 2px solid transparent;
    transition: var(--transition);
}

.about-text p:hover {
    border-left-color: var(--primary);
    color: var(--gray-700);
}

.about-text p:last-child { margin-bottom: 0; }

.about-text strong {
    color: var(--primary);
    font-weight: 600;
}

/* ====== Products Section ====== */
.products {
    background: var(--gray-100);
    position: relative;
}

.products::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--gray-300), transparent);
}

.product-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
}

.product-card {
    background: var(--white);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    border: 1px solid rgba(0, 0, 0, 0.04);
    position: relative;
}

.product-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
    border-color: rgba(217, 119, 6, 0.12);
}

.product-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--primary-gradient);
    opacity: 0;
    transition: opacity 0.35s;
}

.product-card:hover::before { opacity: 1; }

.product-img {
    width: 100%;
    aspect-ratio: 4 / 3;
    background: linear-gradient(135deg, #fafaf9, #f5f5f4);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    overflow: hidden;
}

.product-img img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    transition: transform 0.5s ease;
}

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

.product-body {
    padding: 24px 20px 28px;
}

.product-card h3 {
    font-size: 17px;
    font-weight: 700;
    color: var(--dark);
    margin-bottom: 8px;
    letter-spacing: -0.2px;
}

.product-card p {
    font-size: 14px;
    color: var(--gray-500);
    line-height: 1.65;
}

/* ====== Advantages Section ====== */
.advantages {
    background: var(--white);
}

.advantage-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0;
}

.advantage-item {
    text-align: center;
    padding: 40px 28px;
    transition: var(--transition);
    border-right: 1px solid rgba(0, 0, 0, 0.04);
    border-bottom: 1px solid rgba(0, 0, 0, 0.04);
    position: relative;
}

.advantage-item:nth-child(4n) { border-right: none; }

.advantage-item::after {
    content: '';
    position: absolute;
    inset: 0;
    background: var(--primary-gradient);
    opacity: 0;
    transition: opacity 0.35s;
    z-index: 0;
}

.advantage-item:hover::after {
    opacity: 0.03;
}

.advantage-item > * { position: relative; z-index: 1; }

.advantage-icon {
    width: 56px;
    height: 56px;
    margin: 0 auto 20px;
    background: var(--primary-light);
    border-radius: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    color: var(--primary);
    transition: var(--transition);
}

.advantage-item:hover .advantage-icon {
    background: var(--primary-gradient);
    color: #fff;
    transform: scale(1.05);
    box-shadow: 0 8px 24px rgba(217, 119, 6, 0.2);
}

.advantage-number {
    font-size: 14px;
    font-weight: 800;
    color: var(--primary);
    margin-bottom: 12px;
    letter-spacing: 3px;
    opacity: 0.5;
}

.advantage-item h3 {
    font-size: 17px;
    font-weight: 700;
    color: var(--dark);
    margin-bottom: 10px;
    letter-spacing: -0.2px;
}

.advantage-item p {
    font-size: 14px;
    color: var(--gray-500);
    line-height: 1.65;
}

/* ====== Download Section ====== */
.download {
    background: var(--gray-100);
    position: relative;
}

.download::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--gray-300), transparent);
}

.download-card {
    max-width: 560px;
    margin: 0 auto;
    background: var(--white);
    border-radius: var(--radius-lg);
    padding: 40px;
    text-align: center;
    box-shadow: var(--shadow-sm);
    border: 1px solid rgba(0, 0, 0, 0.04);
}

.download-info {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 16px;
    margin-bottom: 28px;
}

.download-icon {
    width: 56px;
    height: 56px;
    background: var(--primary-light);
    border-radius: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    color: var(--primary);
    flex-shrink: 0;
}

.download-text {
    text-align: left;
}

.download-text h3 {
    font-size: 20px;
    font-weight: 700;
    color: var(--dark);
    margin-bottom: 4px;
}

.download-text p {
    font-size: 14px;
    color: var(--gray-500);
}

.download-btn {
    min-width: 200px;
}

.download-hint {
    margin-top: 16px;
    font-size: 13px;
    color: var(--gray-500);
    min-height: 20px;
}

/* ====== Contact Section ====== */
.contact {
    background: var(--gray-100);
    position: relative;
}

.contact::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--gray-300), transparent);
}

.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 48px;
}

.contact-qrcode {
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.contact-qrcode h3 {
    font-size: 16px;
    font-weight: 700;
    color: var(--dark);
    margin-bottom: 12px;
}

.contact-qrcode img {
    width: 480px;
    height: 480px;
    border-radius: var(--radius);
    border: 1px solid var(--gray-300);
    object-fit: contain;
    background: #fff;
}

.contact-qrcode p {
    font-size: 13px;
    color: var(--gray-500);
    margin-top: 8px;
}

.contact-info { display: flex; flex-direction: column; gap: 16px; }

.contact-item {
    padding: 20px 24px;
    background: var(--white);
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    border: 1px solid rgba(0, 0, 0, 0.04);
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 16px;
}

.contact-item:hover {
    box-shadow: var(--shadow);
    transform: translateX(4px);
    border-left: 3px solid var(--primary);
}

.contact-item-icon {
    width: 42px;
    height: 42px;
    background: var(--primary-light);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    color: var(--primary);
    flex-shrink: 0;
}

.contact-item-content {
    min-width: 0;
}

.contact-label {
    font-size: 12px;
    color: var(--gray-500);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.8px;
    margin-bottom: 2px;
}

.contact-item p {
    font-size: 15px;
    color: var(--gray-900);
    font-weight: 600;
    word-break: break-all;
}

.contact-form {
    background: var(--white);
    padding: 36px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid rgba(0, 0, 0, 0.04);
}

.contact-form h3 {
    font-size: 20px;
    font-weight: 700;
    color: var(--dark);
    margin-bottom: 24px;
    letter-spacing: -0.3px;
}

.form-group { margin-bottom: 18px; }

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 14px 16px;
    border: 1.5px solid var(--gray-300);
    border-radius: var(--radius);
    font-size: 14px;
    font-family: inherit;
    transition: var(--transition);
    outline: none;
    resize: vertical;
    background: var(--gray-100);
}

.form-group input:focus,
.form-group textarea:focus {
    border-color: var(--primary);
    background: #fff;
    box-shadow: 0 0 0 4px rgba(217, 119, 6, 0.08);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: var(--gray-300);
}

/* ====== Footer ====== */
.footer {
    background: var(--dark);
    color: rgba(255, 255, 255, 0.6);
    padding: 60px 0 0;
    position: relative;
}

.footer::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.08), transparent);
}

.footer-content {
    display: grid;
    grid-template-columns: 1.5fr 1fr 1fr;
    gap: 48px;
    padding-bottom: 48px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}

.footer-logo img { height: 34px; width: auto; margin-bottom: 14px; }

.footer-logo p {
    font-size: 14px;
    color: rgba(255, 255, 255, 0.5);
}

.footer h4 {
    color: #fff;
    font-size: 14px;
    font-weight: 700;
    margin-bottom: 20px;
    letter-spacing: 0.5px;
}

.footer-links ul { display: flex; flex-direction: column; gap: 10px; }

.footer-links a {
    font-size: 14px;
    transition: var(--transition);
    color: rgba(255, 255, 255, 0.5);
}

.footer-links a:hover { color: #fff; padding-left: 4px; }

.footer-contact p {
    font-size: 14px;
    margin-bottom: 8px;
    color: rgba(255, 255, 255, 0.5);
}

.footer-bottom {
    text-align: center;
    padding: 24px 0;
    font-size: 13px;
    color: rgba(255, 255, 255, 0.25);
}

/* ====== Back to Top ====== */
.back-to-top {
    position: fixed;
    bottom: 36px;
    right: 28px;
    width: 46px;
    height: 46px;
    border-radius: 12px;
    background: var(--primary-gradient);
    color: #fff;
    border: none;
    font-size: 22px;
    cursor: pointer;
    box-shadow: 0 4px 20px rgba(217, 119, 6, 0.35);
    opacity: 0;
    visibility: hidden;
    transform: translateY(12px);
    transition: 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 {
    transform: translateY(-3px);
    box-shadow: 0 8px 30px rgba(217, 119, 6, 0.45);
}

/* ====== Responsive ====== */
@media (max-width: 992px) {
    .product-grid { grid-template-columns: repeat(2, 1fr); }
    .advantage-grid { grid-template-columns: repeat(2, 1fr); }
    .advantage-item:nth-child(2n) { border-right: none; }
}

@media (max-width: 768px) {
    .section { padding: 70px 0; }
    .section-title { font-size: 28px; }

    .about-text p { padding-left: 16px; font-size: 14.5px; }

    .contact-grid { grid-template-columns: 1fr; gap: 32px; }
    .contact-qrcode img { width: 140px; height: 140px; }
    .footer-content { grid-template-columns: 1fr; gap: 36px; }

    /* Mobile nav */
    .menu-toggle { display: flex; }

    .nav {
        position: fixed;
        top: 0;
        right: -100%;
        width: 75%;
        max-width: 300px;
        height: 100vh;
        background: rgba(255, 255, 255, 0.98);
        backdrop-filter: blur(20px);
        box-shadow: -8px 0 40px rgba(0, 0, 0, 0.1);
        transition: right 0.4s cubic-bezier(0.4, 0, 0.2, 1);
        padding: 90px 28px 36px;
        display: block;
    }

    .nav.active { right: 0; }

    .nav ul { flex-direction: column; gap: 4px; }

    .nav-link {
        display: block;
        padding: 14px 12px;
        font-size: 16px;
        color: var(--gray-700);
        border-radius: 8px;
    }

    .nav-link.active {
        background: var(--primary-light);
        color: var(--primary);
    }

    .hero-buttons { flex-direction: column; align-items: center; }
    .hero-buttons .btn { width: 100%; max-width: 260px; }
}

@media (max-width: 576px) {
    .product-grid,
    .advantage-grid { grid-template-columns: 1fr; }

    .advantage-item { border-right: none; }

    .hero-title { white-space: normal; }

    .logo span { font-size: 13px; }
    .contact-form { padding: 24px 20px; }
    .advantage-item { padding: 30px 20px; }
}