/* ── Reset & Base ── */
    *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
:root {
      --black:  #0a0a0a;
      --gray-9: #111111;
      --gray-8: #1c1c1c;
      --gray-7: #2e2e2e;
      --gray-6: #444444;
      --gray-5: #767676;
      --gray-4: #ababab;
      --gray-3: #d0d0d0;
      --gray-2: #e8e8e8;
      --gray-1: #f4f4f4;
      --white:  #ffffff;
      --fs-xs:  0.75rem;
      --fs-sm:  0.875rem;
      --fs-md:  1rem;
      --fs-lg:  1.25rem;
      --fs-xl:  1.75rem;
      --fs-2xl: 2.5rem;
      --fs-3xl: 3.5rem;
      --fs-4xl: 5rem;
      --lh: 1.7;
      --ease: cubic-bezier(.4,0,.2,1);
    }
html { scroll-behavior: smooth; }
body {
      font-family: 'PingFang SC','Helvetica Neue',Arial,sans-serif;
      background: var(--white);
      color: var(--black);
      line-height: var(--lh);
      -webkit-font-smoothing: antialiased;
    }
a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; }
h1,h2,h3,.cover-title,.hero-title,.about-hero-title,.contact-info-title,.feature-title,.stat-number,.section .label,.pricing-card h3{font-family:"Alimama ShuHeiTi","PingFang SC","Helvetica Neue",Arial,sans-serif;font-weight:700;}
/* ── Page sections (SPA style) ── */
    .page { display: none; min-height: 100vh; padding-top: 72px; }
.page.active { display: block; }
/* ── Navigation ── */
    nav {
      position: fixed; top: 0; left: 0; right: 0; z-index: 100;
      height: 72px;
      background: var(--white);
      border-bottom: 1px solid var(--gray-2);
      display: flex; align-items: center; justify-content: space-between;
      padding: 0 6vw;
    }
.nav-logo {
      height: 36px;
      display: flex;
      align-items: center;
      font-size: 28px;
      font-weight: 800;
      line-height: 1;
      letter-spacing: -0.04em;
      color: var(--black);
      cursor: pointer;
      font-family: "Alimama ShuHeiTi", "Noto Sans SC", sans-serif;
    }
.nav-logo span { color: var(--black); }
.nav-links { display: flex; gap: 2.5rem; align-items: center; }
.nav-links a {
      font-size: var(--fs-sm);
      letter-spacing: 0.06em;
      color: var(--gray-6);
      transition: color .2s var(--ease);
      cursor: pointer;
    }
.nav-links a { position: relative; }
.nav-links a::after {
      content: '';
      position: absolute;
      bottom: -6px;
      left: 0;
      right: 0;
      height: 2px;
      background: var(--black);
      transform: scaleX(0);
      transition: transform .2s var(--ease);
    }
.nav-links a:hover, .nav-links a.active { color: var(--black); }
.nav-links a:hover::after, .nav-links a.active::after { transform: scaleX(1); }
.nav-cta {
      font-size: var(--fs-sm);
      letter-spacing: 0.06em;
      padding: 0.6rem 1.5rem;
      border: 1px solid var(--black);
      color: var(--black);
      background: transparent;
      cursor: pointer;
      transition: background .2s var(--ease), color .2s var(--ease);
    }
.nav-cta:hover { background: var(--black); color: var(--white); }
/* ── Hamburger (mobile) ── */
    .hamburger { display: none; flex-direction: column; gap: 5px; cursor: pointer; padding: 4px; }
.hamburger span { display: block; width: 24px; height: 2px; background: var(--black); transition: all .3s var(--ease); }
.mobile-menu {
      display: none; position: fixed; top: 72px; left: 0; right: 0; z-index: 99;
      background: var(--white); border-bottom: 1px solid var(--gray-2);
      padding: 1.5rem 6vw 2rem; flex-direction: column; gap: 1.25rem;
    }
.mobile-menu.open { display: flex; }
.mobile-menu a { font-size: var(--fs-md); color: var(--gray-7); cursor: pointer; }
/* ── Layout helpers ── */
    .container { max-width: 1120px; margin: 0 auto; padding: 0 6vw; }
.section { padding: 100px 0; }
.section-sm { padding: 72px 0; }
.label {
      font-size: var(--fs-xs); letter-spacing: 0.18em; text-transform: uppercase;
      color: var(--gray-5); margin-bottom: 1rem;
    }
.divider { width: 40px; height: 2px; background: var(--black); margin: 1.5rem 0; }
.divider-center { margin-left: auto; margin-right: auto; }
/* ── Buttons ── */
    .btn-primary {
      display: inline-block;
      padding: 0.9rem 2.5rem;
      background: var(--black);
      color: var(--white);
      font-size: var(--fs-sm);
      letter-spacing: 0.1em;
      cursor: pointer;
      border: 1px solid var(--black);
      transition: background .2s var(--ease), color .2s var(--ease);
    }
.btn-primary:hover { background: var(--gray-7); border-color: var(--gray-7); }
.btn-outline {
      display: inline-block;
      text-decoration: none;
      padding: 0.9rem 2.5rem;
      background: transparent;
      color: var(--black);
      font-size: var(--fs-sm);
      letter-spacing: 0.1em;
      cursor: pointer;
      border: 1px solid var(--black);
      transition: background .2s var(--ease), color .2s var(--ease);
    }
.btn-outline:hover { background: var(--black); color: var(--white); }
.btn-ghost {
      display: inline-flex; align-items: center; gap: 0.5rem;
      font-size: var(--fs-sm); letter-spacing: 0.06em; color: var(--black);
      border-bottom: 1px solid var(--black); padding-bottom: 2px; cursor: pointer;
      transition: opacity .2s;
    }
.btn-ghost:hover { opacity: 0.6; }
/* Video background */
    .hero-video {
      position: absolute;
      inset: 0;
      width: 100%;
      height: 100%;
      object-fit: cover;
      opacity: 0.45;
      z-index: 0;
    }
/* Overlay gradient on top of video */
    .hero-overlay {
      position: absolute;
      inset: 0;
      background: linear-gradient(
        135deg,
        rgba(10,10,10,0.75) 0%,
        rgba(10,10,10,0.45) 50%,
        rgba(10,10,10,0.65) 100%
      );
      z-index: 1;
    }
/* Grid texture (kept as subtle layer) */
    .hero-grid {
      position: absolute; inset: 0;
      background-image:
        linear-gradient(var(--gray-8) 1px, transparent 1px),
        linear-gradient(90deg, var(--gray-8) 1px, transparent 1px);
      background-size: 60px 60px;
      opacity: 0.2;
      z-index: 2;
    }
.hero-content { position: relative; z-index: 3; max-width: 760px; }
.hero-eyebrow {
      font-size: var(--fs-xs); letter-spacing: 0.2em; text-transform: uppercase;
      color: var(--gray-4); margin-bottom: 2rem;
      display: flex; align-items: center; gap: 1rem;
    }
.hero-eyebrow::before {
      content: ''; display: block; width: 32px; height: 1px; background: var(--gray-5);
    }
.hero-title {
      font-size: clamp(2.8rem, 7vw, var(--fs-4xl));
      font-weight: 800;
      line-height: 1.08;
      letter-spacing: -0.04em;
      color: var(--white);
      margin-bottom: 1.75rem;
    }
.hero-title em { color: var(--gray-4); font-style: normal; }
.hero-in .hero-fade { opacity: 1; transform: translateY(0); transition: opacity .7s ease, transform .7s ease; }
.hero-in .hero-fade-1 { transition-delay: .1s; }
.hero-in .hero-fade-2 { transition-delay: .35s; }
.hero-desc {
      font-size: var(--fs-lg);
      color: var(--gray-4);
      line-height: 1.75;
      max-width: 520px;
      margin-bottom: 3rem;
    }
/* Watch video button */
    .btn-watch {
      display: inline-flex; align-items: center; gap: 0.75rem;
      font-size: var(--fs-sm); letter-spacing: 0.06em;
      color: var(--gray-3);
      cursor: pointer;
      transition: color .2s;
      background: none; border: none; padding: 0;
      font-family: inherit;
    }
.btn-watch:hover { color: var(--white); }
.btn-watch-icon {
      width: 42px; height: 42px;
      border-radius: 50%;
      border: 1px solid rgba(255,255,255,0.3);
      display: flex; align-items: center; justify-content: center;
      transition: background .2s, border-color .2s;
      flex-shrink: 0;
    }
.btn-watch:hover .btn-watch-icon {
      background: rgba(255,255,255,0.12);
      border-color: rgba(255,255,255,0.6);
    }
.btn-watch-icon svg { margin-left: 3px; }
/* ── Video lightbox modal ── */
    .video-modal {
      display: none;
      position: fixed; inset: 0; z-index: 999;
      background: rgba(0,0,0,0.92);
      align-items: center; justify-content: center;
    }
.video-modal.open { display: flex; }
.video-modal-inner {
      position: relative;
      width: 90vw; max-width: 1000px;
    }
.video-modal-inner video {
      width: 100%; display: block;
      outline: none;
    }
.video-modal-close {
      position: absolute; top: -44px; right: 0;
      font-size: var(--fs-lg); color: var(--gray-4);
      cursor: pointer; background: none; border: none;
      font-family: inherit; letter-spacing: 0.05em;
      transition: color .2s;
    }
.video-modal-close:hover { color: var(--white); }
/* Stats strip */
    .stats-strip { background: var(--gray-1); border-top: 1px solid var(--gray-2); border-bottom: 1px solid var(--gray-2); }
.stats-strip .container {
      display: grid; grid-template-columns: repeat(4, 1fr);
    }
.stat-item {
      padding: 3rem 2rem;
      border-right: 1px solid var(--gray-2);
      text-align: center;
    }
.stat-item:last-child { border-right: none; }
.stat-number {
      font-size: var(--fs-3xl); font-weight: 800; letter-spacing: -0.04em;
      line-height: 1;
    }
.stat-label {
      font-size: var(--fs-xs); letter-spacing: 0.12em; text-transform: uppercase;
      color: var(--gray-5); margin-top: 0.5rem;
    }
.feature-card:hover { background: var(--gray-1); }
.feature-icon {
      width: 40px; height: 40px;
      margin-bottom: 1.5rem;
      opacity: 0.85;
    }
.feature-desc { font-size: var(--fs-sm); color: var(--gray-5); line-height: 1.75; }
.marquee-track span.dot { color: var(--gray-7); }
@keyframes marquee {
      from { transform: translateX(0); }
      to { transform: translateX(-50%); }
    }
/* CTA band */
    .cta-band { background: var(--black); }
.cta-band .container {
      padding-top: 96px; padding-bottom: 96px;
      display: flex; justify-content: space-between; align-items: center; gap: 3rem;
      flex-wrap: wrap;
    }
/* ═══════════════════════════════════════════
       PAGE 2 — ABOUT
    ═══════════════════════════════════════════ */
    .about-hero {
      background: var(--gray-1);
      border-bottom: 1px solid var(--gray-2);
      padding: 96px 6vw 80px;
    }
.about-hero-label { font-size: var(--fs-xs); letter-spacing: 0.18em; text-transform: uppercase; color: var(--gray-5); margin-bottom: 1.5rem; }
.about-hero-title {
      font-size: clamp(2rem, 5vw, var(--fs-3xl));
      font-weight: 800; letter-spacing: -0.04em; line-height: 1.1;
      max-width: 680px;
    }
.about-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 6rem; align-items: start; }
.about-body { font-size: var(--fs-md); color: var(--gray-6); line-height: 2; }
.about-body p + p { margin-top: 1.25rem; }
.timeline { margin-top: 0; }
.timeline-item { display: flex; gap: 2rem; padding-bottom: 2.5rem; border-bottom: 1px solid var(--gray-2); margin-bottom: 2.5rem; }
.timeline-item:last-child { border-bottom: none; margin-bottom: 0; padding-bottom: 0; }
.timeline-year { font-size: var(--fs-sm); font-weight: 700; letter-spacing: 0.05em; color: var(--gray-5); min-width: 60px; padding-top: 3px; }
.timeline-text { font-size: var(--fs-sm); color: var(--gray-6); line-height: 1.75; }
.timeline-text strong { color: var(--black); }
.values-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 2px; background: var(--gray-2); border: 1px solid var(--gray-2); margin-top: 4rem; }
.value-card { background: var(--white); padding: 2.5rem; }
.value-num { font-size: var(--fs-xs); letter-spacing: 0.12em; color: var(--gray-4); margin-bottom: 1rem; }
.value-desc { font-size: var(--fs-sm); color: var(--gray-5); line-height: 1.75; }
.team-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 2.5rem; margin-top: 4rem; }
.team-card { width: 100%; text-align: left; padding: 2rem; background: var(--white); border: 1px solid var(--gray-2); transition: border-color .2s var(--ease); }
.team-card:hover { border-color: var(--gray-4); }
.team-name { font-size: var(--fs-lg); font-weight: 700; margin-bottom: 0.5rem; letter-spacing: -0.02em; }
.team-role { font-size: var(--fs-sm); color: var(--gray-5); margin-bottom: 1rem; padding-bottom: 1rem; border-bottom: 1px solid var(--gray-2); }
.team-desc { font-size: var(--fs-sm); color: var(--gray-6); line-height: 1.7; }
/* ═══════════════════════════════════════════
       PAGE 3 — PRODUCTS
    ═══════════════════════════════════════════ */
    .products-hero {
      background: var(--black);
      padding: 96px 6vw 80px;
    }
.products-hero .about-hero-label { color: var(--gray-6); }
.products-hero .about-hero-title { color: var(--white); }
.product-list { margin-top: 0; }
.product-item {
      display: grid; grid-template-columns: 1fr 2fr; gap: 4rem;
      padding: 4rem 0;
      border-bottom: 1px solid var(--gray-2);
      align-items: start;
    }
.product-item:last-child { border-bottom: none; }
.product-meta {}
.product-num { font-size: var(--fs-xs); letter-spacing: 0.18em; color: var(--gray-4); margin-bottom: 1rem; }
.product-name { font-size: var(--fs-2xl); font-weight: 800; letter-spacing: -0.03em; line-height: 1.15; margin-bottom: 1.25rem; }
.product-tag {
      display: inline-block;
      font-size: var(--fs-xs); letter-spacing: 0.1em; text-transform: uppercase;
      border: 1px solid var(--gray-3); color: var(--gray-5);
      padding: 0.3rem 0.8rem;
    }
.product-detail {}
.product-desc { font-size: var(--fs-md); color: var(--gray-6); line-height: 2; margin-bottom: 2rem; }
.product-features { list-style: none; display: flex; flex-direction: column; gap: 0.75rem; }
.product-features li {
      font-size: var(--fs-sm); color: var(--gray-6);
      display: flex; align-items: flex-start; gap: 0.75rem;
    }
.product-features li::before {
      content: '—'; color: var(--gray-4); flex-shrink: 0; margin-top: 2px;
    }
.pricing-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 2px; background: var(--gray-2); border: 1px solid var(--gray-2); margin-top: 4rem; }
.pricing-card { background: var(--white); padding: 2.5rem; position: relative; }
.pricing-card.featured { background: var(--black); }
.pricing-badge {
      position: absolute; top: 2rem; right: 2rem;
      font-size: var(--fs-xs); letter-spacing: 0.1em; text-transform: uppercase;
      color: var(--gray-4); border: 1px solid var(--gray-6);
      padding: 0.2rem 0.6rem;
    }
.pricing-tier { font-size: var(--fs-xs); letter-spacing: 0.18em; text-transform: uppercase; color: var(--gray-5); margin-bottom: 1.25rem; }
.pricing-card.featured .pricing-tier { color: var(--gray-6); }
.pricing-price {
      font-size: var(--fs-2xl); font-weight: 800; letter-spacing: -0.04em;
      margin-bottom: 0.25rem;
    }
.pricing-card.featured .pricing-price { color: var(--white); }
.pricing-period { font-size: var(--fs-xs); color: var(--gray-5); margin-bottom: 2rem; }
.pricing-card.featured .pricing-period { color: var(--gray-6); }
.pricing-list { list-style: none; display: flex; flex-direction: column; gap: 0.75rem; margin-bottom: 2rem; }
.pricing-list li { font-size: var(--fs-sm); color: var(--gray-6); display: flex; gap: 0.6rem; }
.pricing-card.featured .pricing-list li { color: var(--gray-4); }
.pricing-list li::before { content: '✓'; color: var(--gray-4); flex-shrink: 0; }
.pricing-card.featured .pricing-list li::before { color: var(--gray-5); }
/* ═══════════════════════════════════════════
       PAGE 4 — CONTACT
    ═══════════════════════════════════════════ */
    .contact-layout {
      display: grid; grid-template-columns: 1fr 1fr; gap: 0;
      min-height: calc(100vh - 72px);
    }
.contact-info {
      background: var(--black); padding: 96px 6vw;
      display: flex; flex-direction: column; justify-content: center;
    }
.contact-info-label { font-size: var(--fs-xs); letter-spacing: 0.18em; text-transform: uppercase; color: var(--gray-6); margin-bottom: 1.5rem; }
.contact-info-title {
      font-size: clamp(2rem, 4vw, var(--fs-3xl));
      font-weight: 800; letter-spacing: -0.04em; line-height: 1.1;
      color: var(--white); margin-bottom: 2rem;
    }
.contact-info-desc { font-size: var(--fs-md); color: var(--gray-5); line-height: 1.9; max-width: 400px; margin-bottom: 3.5rem; }
.contact-details { display: flex; flex-direction: column; gap: 1.75rem; }
.contact-detail-item {}
.contact-detail-label { font-size: var(--fs-xs); letter-spacing: 0.14em; text-transform: uppercase; color: var(--gray-6); margin-bottom: 0.4rem; }
.contact-detail-value { font-size: var(--fs-md); color: var(--gray-3); }
.contact-form-wrap { background: var(--white); padding: 96px 6vw; display: flex; flex-direction: column; justify-content: center; }
.form-group { margin-bottom: 1.5rem; }
.form-label { display: block; font-size: var(--fs-xs); letter-spacing: 0.1em; text-transform: uppercase; color: var(--gray-6); margin-bottom: 0.6rem; }
.form-input, .form-textarea, .form-select {
      width: 100%; padding: 0.85rem 1rem;
      background: var(--gray-1);
      border: 1px solid var(--gray-2);
      color: var(--black); font-size: var(--fs-sm);
      font-family: inherit;
      outline: none;
      transition: border-color .2s var(--ease);
      appearance: none;
    }
.form-input:focus, .form-textarea:focus, .form-select:focus {
      border-color: var(--black);
    }
.form-textarea { resize: vertical; min-height: 120px; }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 1.25rem; }
.form-submit {
      width: 100%; padding: 1rem; background: var(--black); color: var(--white);
      font-size: var(--fs-sm); letter-spacing: 0.1em; border: none; cursor: pointer;
      font-family: inherit; transition: background .2s var(--ease);
    }
.form-submit:hover { background: var(--gray-7); }
.form-success {
      display: none; text-align: center; padding: 3rem 0;
    }
.form-success-icon { font-size: 3rem; margin-bottom: 1rem; }
.form-success-text { font-size: var(--fs-md); color: var(--gray-6); }
/* ── Footer ── */
    footer {
      background: var(--black);
      border-top: 1px solid var(--gray-8);
      padding: 3rem 6vw;
    }
.footer-inner {
      display: flex; align-items: center; justify-content: space-between;
      flex-wrap: wrap; gap: 1.5rem;
    }
.footer-logo { font-size: var(--fs-lg); font-weight: 800; letter-spacing: -0.03em; color: var(--white); }
.footer-logo span { color: var(--white); }
.footer-copy { font-size: var(--fs-xs); color: var(--gray-6); letter-spacing: 0.06em; }
.footer-links { display: flex; flex-wrap: wrap; gap: 2rem; }
.footer-links a { font-size: var(--fs-xs); color: var(--gray-6); letter-spacing: 0.06em; cursor: pointer; transition: color .2s; white-space: nowrap; }
.footer-links a:hover { color: var(--gray-3); }
@media (min-width: 901px) {
      .hero-actions { flex-wrap: nowrap; }
    }
.language-toggle:hover span:not(.active), .language-toggle:focus-visible span:not(.active) { color:#555; }