/* ===== CSS Variables ===== */
:root {
    --bg-black: #000000;
    --bg-dark: #0a0a0a;
    --bg-white: #f5f5f7;
    --text-white: #f5f5f7;
    --text-gray: #86868b;
    --text-black: #1d1d1f;
    --accent: #0071e3;
    --accent-hover: #0077ed;
    --nav-bg: rgba(0, 0, 0, 0.8);
    --transition: all 0.3s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background: var(--bg-black);
    color: var(--text-white);
    line-height: 1.6;
    overflow-x: hidden;
}

a {
    text-decoration: none;
    color: inherit;
}

/* ===== Navigation ===== */
nav {
    position: fixed;
    top: 0;
    width: 100%;
    height: 48px;
    background: var(--nav-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    z-index: 1000;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    height: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 20px;
}

.logo {
    font-size: 20px;
    font-weight: 700;
    letter-spacing: 0.1em;
    color: var(--text-white);
}

.logo img {
    height: 30px;
    vertical-align: middle;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 30px;
}

.nav-links a {
    color: #d1d1d1;
    font-size: 12px;
    font-weight: 400;
    transition: var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
    color: #fff;
}

/* ===== Language Switcher ===== */
.lang-switch {
    display: flex;
    gap: 8px;
    margin-left: 20px;
}

.lang-btn {
    background: transparent;
    border: 1px solid #333;
    color: #86868b;
    padding: 4px 10px;
    font-size: 11px;
    border-radius: 4px;
    cursor: pointer;
    transition: var(--transition);
    font-family: inherit;
}

.lang-btn:hover {
    border-color: #666;
    color: #fff;
}

.lang-btn.active {
    background: var(--accent);
    border-color: var(--accent);
    color: #fff;
}

/* ===== Hero Section ===== */
.hero {
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding-top: 48px;
    background: radial-gradient(ellipse at center top, #1a1a1a 0%, var(--bg-black) 70%);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 800px;
    height: 800px;
    background: radial-gradient(circle, rgba(255,255,255,0.08) 0%, transparent 60%);
    pointer-events: none;
}

.hero-content {
    position: relative;
    z-index: 1;
}

.hero h1 {
    font-size: 100px;
    font-weight: 700;
    letter-spacing: -0.03em;
    margin-bottom: 10px;
    background: linear-gradient(135deg, #fff 0%, #888 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero p {
    font-size: 28px;
    font-weight: 400;
    color: var(--text-gray);
    margin-bottom: 40px;
}

.hero-cta {
    display: flex;
    gap: 20px;
    justify-content: center;
}

/* ===== Buttons ===== */
.btn {
    display: inline-block;
    padding: 14px 28px;
    border-radius: 980px;
    font-size: 17px;
    font-weight: 500;
    transition: var(--transition);
    cursor: pointer;
}

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

.btn-primary:hover {
    background: var(--accent-hover);
    transform: scale(1.02);
}

.btn-outline {
    background: transparent;
    border: 1px solid var(--text-gray);
    color: var(--text-white);
}

.btn-outline:hover {
    border-color: var(--text-white);
    background: rgba(255,255,255,0.1);
}

/* ===== Featured Section ===== */
.featured {
    padding: 120px 20px;
    background: var(--bg-dark);
}

.section-title {
    text-align: center;
    font-size: 48px;
    font-weight: 700;
    margin-bottom: 60px;
}

.product-grid {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    padding: 0 20px;
}

.product-card {
    background: #1a1a1a;
    border-radius: 20px;
    padding: 40px;
    text-align: center;
    transition: var(--transition);
    display: block;
}

.product-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 40px rgba(0,0,0,0.4);
}

.card-image {
    font-size: 80px;
    margin-bottom: 20px;
    width: 100%;
    height: 200px;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    border-radius: 12px;
}

.card-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.product-card h3 {
    font-size: 24px;
    font-weight: 600;
    margin-bottom: 10px;
}

.product-card p {
    color: var(--text-gray);
    margin-bottom: 20px;
}

.product-card .link {
    color: var(--accent);
    font-size: 14px;
}

/* ===== Teaser Section ===== */
.teaser {
    padding: 150px 20px;
    background: linear-gradient(180deg, var(--bg-black) 0%, #0d0d0d 100%);
    text-align: center;
}

.teaser h2 {
    font-size: 56px;
    font-weight: 700;
    margin-bottom: 20px;
}

.teaser p {
    font-size: 24px;
    color: var(--text-gray);
    margin-bottom: 40px;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

/* ===== Footer ===== */
footer {
    background: #1d1d1f;
    padding: 60px 20px 20px;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 40px;
    padding-bottom: 40px;
    border-bottom: 1px solid #333;
}

.footer-section h4 {
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 20px;
    color: var(--text-white);
}

.footer-section p,
.footer-section a {
    font-size: 12px;
    color: var(--text-gray);
    display: block;
    margin-bottom: 10px;
    transition: var(--transition);
}

.footer-section a:hover {
    color: var(--text-white);
}

.footer-bottom {
    max-width: 1200px;
    margin: 0 auto;
    padding-top: 20px;
    text-align: center;
    color: var(--text-gray);
    font-size: 12px;
}

/* ===== Animations ===== */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.8s ease-out;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ===== Page Header (for sub-pages) ===== */
.page-header {
    padding: 150px 20px 80px;
    text-align: center;
    background: radial-gradient(ellipse at center top, #1a1a1a 0%, var(--bg-black) 70%);
}

.page-header h1 {
    font-size: 64px;
    font-weight: 700;
    margin-bottom: 15px;
}

.page-header p {
    font-size: 24px;
    color: var(--text-gray);
}

/* ===== Product Detail ===== */
.product-detail {
    max-width: 1200px;
    margin: 0 auto;
    padding: 60px 20px;
}

.product-hero {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
    margin-bottom: 80px;
}

.product-hero-image {
    background: linear-gradient(135deg, #333 0%, #111 100%);
    border-radius: 20px;
    height: 400px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 120px;
    overflow: hidden;
}

.product-hero-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.product-hero-content h2 {
    font-size: 48px;
    font-weight: 700;
    margin-bottom: 20px;
}

.product-hero-content .subtitle {
    font-size: 24px;
    color: var(--text-gray);
    margin-bottom: 30px;
}

.product-hero-content .price {
    font-size: 36px;
    font-weight: 600;
    margin-bottom: 30px;
}

.product-features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    margin-top: 60px;
}

.feature-item {
    background: #1a1a1a;
    padding: 30px;
    border-radius: 16px;
    text-align: center;
}

.feature-item h4 {
    font-size: 18px;
    margin-bottom: 10px;
}

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

/* ===== Product Description ===== */
.product-description {
    max-width: 900px;
    margin: 0 auto;
    padding: 80px 20px;
}

.description-content {
    background: #1a1a1a;
    border-radius: 20px;
    padding: 50px;
}

.description-content h2 {
    font-size: 32px;
    font-weight: 700;
    margin-bottom: 20px;
}

.description-content h3 {
    font-size: 24px;
    font-weight: 600;
    margin: 40px 0 20px;
    color: var(--text-gray);
}

.description-content p {
    font-size: 16px;
    line-height: 1.8;
    color: #b0b0b0;
    margin-bottom: 20px;
}

/* ===== Size Chart ===== */
.size-chart {
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    margin-top: 20px;
}

.size-item {
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: #2a2a2a;
    border: 1px solid #444;
    border-radius: 10px;
    font-size: 16px;
    font-weight: 600;
    transition: var(--transition);
    cursor: pointer;
}

.size-item:hover {
    background: var(--accent);
    border-color: var(--accent);
}

/* ===== Color Options ===== */
.color-options {
    display: flex;
    gap: 15px;
    margin-top: 20px;
}

.color-item {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    cursor: pointer;
    transition: var(--transition);
    border: 2px solid transparent;
}

.color-item:hover {
    transform: scale(1.1);
    border-color: var(--accent);
}

/* ===== Brand Section ===== */
.brand-section {
    padding: 20px 20px;
    background: var(--bg-dark);
    border-bottom: 1px solid #222;
}

.brand-section:last-of-type {
    border-bottom: none;
}

.brand-header {
    text-align: center;
    padding: 20px 0 20px;
    margin-bottom: 10px;
}

.brand-logo {
    font-size: 32px;
    display: inline-block;
    margin-right: 10px;
    vertical-align: middle;
}

.brand-header h2 {
    font-size: 24px;
    font-weight: 700;
    letter-spacing: 0.15em;
    color: #fff;
    text-transform: uppercase;
    display: inline;
    vertical-align: middle;
}

.brand-chinese {
    font-size: 18px;
    color: #888;
    margin-top: 8px;
    letter-spacing: 0.1em;
}

/* ===== Brand Navigation ===== */
.brand-nav {
    position: sticky;
    top: 48px;
    background: linear-gradient(180deg, rgba(10,10,10,0.98) 0%, rgba(15,15,15,0.95) 100%);
    backdrop-filter: blur(20px);
    padding: 10px 0;
    z-index: 100;
    border-bottom: 1px solid rgba(255,255,255,0.05);
}

.brand-nav-list {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 20px;
    list-style: none;
    flex-wrap: wrap;
}

.brand-nav-list li {
    position: relative;
}

.brand-nav-list li a {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 4px;
    padding: 8px 16px;
    font-size: 12px;
    font-weight: 500;
    color: #888;
    transition: all 0.3s ease;
    border-right: 1px solid rgba(255,255,255,0.08);
}

.brand-nav-list li:last-child a {
    border-right: none;
}

.brand-nav-list li a:hover {
    color: #fff;
    background: rgba(255,255,255,0.03);
}

.brand-nav-list li a.active {
    color: #fff;
}

.brand-nav-list li a.active::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 40px;
    height: 2px;
    background: linear-gradient(90deg, transparent, #fff, transparent);
}

.nav-brand-logo {
    font-size: 20px;
}

.brand-nav-img {
    height: 36px;
    width: auto;
    object-fit: contain;
}

.brand-nav-list li a:hover,
.brand-nav-list li a.active {
    background: var(--accent);
    border-color: var(--accent);
    color: #fff;
    transform: scale(1.05);
}

/* ===== About Page ===== */
.about-hero {
    padding: 150px 20px 80px;
    text-align: center;
    background: radial-gradient(ellipse at center top, #1a1a1a 0%, var(--bg-black) 70%);
}

.about-hero h1 {
    font-size: 72px;
    font-weight: 700;
    margin-bottom: 20px;
}

.about-hero p {
    font-size: 24px;
    color: var(--text-gray);
    max-width: 700px;
    margin: 0 auto;
}

.about-content {
    max-width: 900px;
    margin: 0 auto;
    padding: 80px 20px;
}

.about-section {
    margin-bottom: 80px;
}

.about-section h2 {
    font-size: 40px;
    font-weight: 700;
    margin-bottom: 20px;
}

.about-section p {
    font-size: 18px;
    color: var(--text-gray);
    line-height: 1.8;
}

.stats {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 30px;
    margin-top: 60px;
}

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

.stat-item .number {
    font-size: 48px;
    font-weight: 700;
    color: var(--accent);
}

.stat-item .label {
    font-size: 14px;
    color: var(--text-gray);
}

/* ===== Brand Section ===== */
.brand-section {
    padding: 60px 20px;
    background: var(--bg-dark);
    border-bottom: 1px solid #222;
}

.brand-section:last-of-type {
    border-bottom: none;
}

.brand-header {
    text-align: center;
    padding: 40px 0 50px;
    margin-bottom: 20px;
}

.brand-logo {
    font-size: 48px;
    display: block;
    margin-bottom: 15px;
}

.brand-header h2 {
    font-size: 42px;
    font-weight: 800;
    letter-spacing: 0.15em;
    background: linear-gradient(135deg, #fff 0%, #c0c0c0 50%, #ffd700 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* ===== Mobile Responsive ===== */
@media (max-width: 768px) {
    .nav-links {
        display: none;
    }

    .hero h1 {
        font-size: 56px;
    }

    .hero p {
        font-size: 20px;
    }

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

    .section-title {
        font-size: 36px;
    }

    .product-hero {
        grid-template-columns: 1fr;
    }

    .product-hero-image {
        height: 250px;
        font-size: 80px;
    }

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

    .about-hero h1 {
        font-size: 42px;
    }
}

/* ===== White Background Variant ===== */
body.white-bg {
    background: #ffffff;
    color: #1d1d1f;
}

body.white-bg .page-header {
    background: #ffffff;
}

body.white-bg .page-header h1 {
    color: #1d1d1f;
}

body.white-bg .page-header p {
    color: #666;
}

body.white-bg .brand-section {
    background: #ffffff;
    padding: 40px 20px;
}

body.white-bg .product-card {
    background: #f5f5f7;
    border-radius: 12px;
    padding: 20px;
}

body.white-bg .product-card h3 {
    color: #1d1d1f;
}

body.white-bg .product-card p {
    color: #666;
}

body.white-bg .product-card .price {
    color: #0071e3;
}

body.white-bg footer {
    background: #f5f5f7;
}

body.white-bg footer h4 {
    color: #1d1d1f;
}

body.white-bg footer a {
    color: #666;
}

body.white-bg footer p {
    color: #86868b;
}