:root {
  --blue: #1b579c;
  --blue-dark: #14467e;
  --ink: #172b40;
  --body: #536170;
  --line: #dfe5e9;
  --surface: #f3f5f7;
  --white: #fff;
  --gutter: clamp(24px, 4.45vw, 80px);
  color-scheme: light;
  font-family: Arial, Helvetica, sans-serif;
  color: var(--ink);
  background: var(--white);
  font-synthesis: none;
  -webkit-font-smoothing: antialiased;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 98px; }
body { margin: 0; }
img { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button, a { -webkit-tap-highlight-color: transparent; }
a:focus-visible { outline: 3px solid var(--blue); outline-offset: 5px; }
.contact a:focus-visible { outline-color: white; }
figure, p, h1, h2, h3, h4, dl { margin: 0; }
p { line-height: 1.65; }
.container { width: min(100% - var(--gutter) * 2, 1280px); margin-inline: auto; }
.section-pad { padding-block: 100px; }
.eyebrow { color: var(--blue); font-size: .8125rem; line-height: 1.6; font-weight: 700; letter-spacing: .095em; text-transform: uppercase; }
h1, h2, h3, h4 { font-weight: 600; }
h2 { font-size: clamp(2rem, 3vw, 2.75rem); line-height: 1.14; letter-spacing: -.025em; }
.section-heading { margin-bottom: 42px; }
.section-heading .eyebrow { margin-bottom: 13px; }
.skip-link { position: absolute; z-index: 20; left: 16px; top: 8px; background: white; padding: 14px; transform: translateY(-150%); }
.skip-link:focus { transform: translateY(0); }

.site-header { background: var(--white); border-bottom: 1px solid var(--line); position: sticky; top: 0; z-index: 10; }
.header-inner { min-height: 84px; display: flex; justify-content: space-between; align-items: center; gap: 28px; }
.brand img { width: 169px; height: auto; }
.main-nav { display: flex; align-items: center; gap: 38px; }
.main-nav a { font-size: .9375rem; font-weight: 500; padding-block: 13px; }
.main-nav a:hover { color: var(--blue); }
.main-nav .nav-contact { color: var(--blue); border: 1px solid var(--blue); border-radius: 2px; padding: 11px 22px; transition: color .15s, background .15s; }
.main-nav .nav-contact:hover { background: var(--blue); color: var(--white); }

.hero { background: var(--surface); border-bottom: 1px solid var(--line); overflow: clip; }
.hero-inner { display: grid; grid-template-columns: 48% 52%; align-items: stretch; min-height: 586px; }
.hero-copy { padding: 79px 36px 77px 0; position: relative; z-index: 1; }
.hero-copy .eyebrow { font-size: .75rem; letter-spacing: .08em; margin-bottom: 25px; }
h1 { font-size: clamp(3rem, 4.45vw, 4rem); line-height: 1.08; letter-spacing: -.035em; margin-bottom: 28px; }
h1 span { color: var(--blue); }
.hero-lead { font-size: 1.25rem; color: var(--ink); line-height: 1.55; margin-bottom: 15px; }
.hero-description { font-size: 1rem; color: var(--body); max-width: 407px; }
.hero-actions { display: flex; align-items: center; flex-wrap: wrap; gap: 30px; margin-top: 33px; }
.button { min-height: 48px; padding: 14px 21px; display: inline-flex; justify-content: center; align-items: center; gap: 24px; font-size: .9375rem; font-weight: 500; line-height: 1.3; border: 1px solid transparent; border-radius: 2px; transition: background .15s, color .15s; }
.button span { font-size: 1.2rem; line-height: 1; }
.button-primary { background: var(--blue); color: white; }
.button-primary:hover { background: var(--blue-dark); }
.text-link { font-size: .9375rem; font-weight: 500; border-bottom: 1px solid #9ba7b2; padding-block: 5px; }
.text-link:hover { color: var(--blue); border-color: var(--blue); }
.hero-visual { position: relative; margin-right: calc(-1 * max(var(--gutter), (100vw - 1280px) / 2)); background: #fafafa; }
.hero-visual > img { height: 100%; width: 100%; object-fit: cover; object-position: 56% 55%; }
.hero-visual::after { content: ''; position: absolute; inset: auto 0 0; height: 50%; background: linear-gradient(to bottom, transparent, rgba(19, 27, 32, .78)); pointer-events: none; }
.hero-caption { position: absolute; z-index: 1; left: 28px; right: 28px; bottom: 28px; display: flex; flex-direction: column; align-items: flex-start; color: white; font-family: Arial, Helvetica, sans-serif; font-weight: 700; letter-spacing: 0; text-shadow: 0 1px 2px rgba(0, 0, 0, .3); }
.hero-caption-model { font-size: clamp(1.9rem, 2.8vw, 2.5rem); font-weight: 700; line-height: 1.12; }
.hero-caption-category { font-size: clamp(1.125rem, 1.9vw, 1.75rem); line-height: 1.2; margin-top: 5px; }
.hero-caption-description { display: block; width: 100%; border-top: 1px solid rgba(255, 255, 255, .72); margin-top: 15px; padding-top: 11px; font-size: clamp(.875rem, 1.1vw, 1rem); line-height: 1.5; }

.product-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 32px; }
.product { display: flex; min-width: 0; flex-direction: column; }
.product-photo { aspect-ratio: .88; height: auto; background: var(--surface); border: 1px solid var(--line); display: flex; align-items: center; justify-content: center; overflow: hidden; }
.product-photo img { width: 100%; height: 100%; object-fit: contain; }
.product-photo-mic { background: white; }
.product-photo-mic img { width: 84%; height: 84%; }
.product-photo-link img { width: 91%; height: 91%; }
.product-photo-system { background: #eee6d9; }
.product-photo-system img { object-fit: contain; object-position: center; }
.product-copy { display: flex; flex-direction: column; flex: 1; padding-top: 27px; }
.product-category { color: var(--body); font-size: .875rem; margin-bottom: 6px; }
.product h3 { font-size: 2rem; letter-spacing: -.025em; line-height: 1.2; margin-bottom: 17px; }
.product h4 { font-size: 1.0625rem; line-height: 1.45; margin-bottom: 13px; min-height: 49px; }
.product-copy > p:not(.product-category) { font-size: 1rem; line-height: 1.65; color: var(--body); }
.feature-list { padding: 0; margin: 25px 0 0; list-style: none; border-top: 1px solid var(--line); }
.feature-list li { color: var(--body); font-size: .875rem; line-height: 1.6; position: relative; padding: 10px 0 0 14px; }
.feature-list li:first-child { padding-top: 18px; }
.feature-list li::before { content: ""; position: absolute; width: 4px; height: 4px; left: 0; top: 20px; background: var(--blue); }
.feature-list li:first-child::before { top: 28px; }
.battery-facts { display: flex; gap: 24px; margin: 24px 0 0; padding-block: 17px 5px; }
.battery-facts > div { display: flex; flex-direction: column-reverse; gap: 6px; }
.battery-facts > div + div { border-left: 1px solid var(--line); padding-left: 24px; }
.battery-facts dt { font-size: .875rem; line-height: 1.4; color: var(--body); }
.battery-facts dd { margin: 0; color: var(--blue); font-size: 2rem; line-height: 1; }
.battery-facts dd span { font-size: .875rem; }
.product-link { margin-top: auto; padding-top: 29px; display: flex; justify-content: space-between; align-items: center; gap: 10px; color: var(--blue); font-size: .9375rem; font-weight: 600; line-height: 1.5; }
.product-link:hover { text-decoration: underline; text-underline-offset: 5px; }
.product-link span { font-size: 1.3rem; }

.configurations { background: var(--surface); border-block: 1px solid var(--line); }
.configuration-inner { display: grid; grid-template-columns: 1.05fr 1fr 1fr; gap: 48px; }
.configuration-heading .eyebrow { margin-bottom: 15px; }
.configuration-heading h2 { font-size: 2.125rem; max-width: 350px; }
.configuration-option { border-left: 1px solid #cdd7e0; padding-left: 36px; }
.option-number { color: var(--blue); font-size: .875rem; margin-bottom: 20px; }
.configuration-option h3 { font-size: 1.1875rem; line-height: 1.4; margin-bottom: 18px; }
.configuration-models { display: flex; flex-wrap: wrap; align-items: center; gap: 11px; color: var(--blue); font-size: .875rem; font-weight: 600; margin-bottom: 15px; }
.configuration-models a:hover { text-decoration: underline; text-underline-offset: 4px; }
.configuration-models span { color: #738495; font-weight: 400; }
.configuration-option > p:last-child { color: var(--body); font-size: 1rem; line-height: 1.7; }
.about-inner { display: grid; grid-template-columns: 1fr 1fr; gap: 100px; align-items: center; }
.about .eyebrow { margin-bottom: 18px; }
.about-copy { color: var(--body); font-size: 1.125rem; }
.about-copy p { line-height: 1.8; }
.about-copy p + p { margin-top: 17px; }
.about-copy a { color: var(--ink); text-decoration: underline; text-decoration-color: #bcc8d2; text-underline-offset: 4px; }
.about-copy a:hover { color: var(--blue); }
.brand-focus { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 28px; margin-top: 44px; }
.brand-focus > div { border-top: 2px solid var(--line); padding-top: 19px; }
.brand-focus h3 { font-size: 1rem; line-height: 1.5; margin-bottom: 9px; }
.brand-focus p { font-size: 1rem; color: var(--body); }
.classrooms { padding-top: 0; }
.classrooms-heading { display: flex; justify-content: space-between; align-items: flex-end; gap: 55px; margin-bottom: 37px; padding-top: 51px; border-top: 1px solid var(--line); }
.classrooms-heading .eyebrow { margin-bottom: 13px; }
.classrooms-heading h2 { font-size: clamp(1.875rem, 2.8vw, 2.5rem); }
.classrooms-heading > p { max-width: 340px; flex: 0 1 340px; font-size: 1rem; color: var(--body); }
.classroom-grid { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 320px); gap: 38px; align-items: end; }
.classroom-main img { width: 100%; height: auto; aspect-ratio: 16/9; object-fit: cover; object-position: center 75%; }
.classroom-supporting { max-width: 320px; }
.classroom-supporting img { width: 100%; height: auto; }
.classrooms figcaption { margin-top: 14px; font-size: .875rem; line-height: 1.6; color: var(--body); }
.classroom-photo { display: block; cursor: zoom-in; }
.classroom-gallery { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 34px 28px; margin-top: 42px; }
.classroom-gallery figure { min-width: 0; }
.classroom-gallery .classroom-photo { aspect-ratio: 4/3; background: var(--surface); overflow: hidden; }
.classroom-gallery img { width: 100%; height: 100%; object-fit: cover; }
.classroom-gallery .classroom-photo-wide img { object-fit: contain; }
.classroom-gallery .classroom-photo-detail img { object-position: center 30%; }
.classroom-gallery .classroom-photo-portrait img { object-position: center 45%; }
.faq { background: var(--surface); border-top: 1px solid var(--line); }
.faq-inner { display: grid; grid-template-columns: 1fr 1.65fr; gap: 80px; align-items: start; }
.faq-heading .eyebrow { margin-bottom: 15px; }
.faq-heading h2 { font-size: clamp(2rem, 3vw, 2.5rem); }
.faq-list { min-width: 0; border-top: 1px solid #cdd7e0; }
.faq-list details { border-bottom: 1px solid #cdd7e0; }
.faq-list summary { display: flex; align-items: center; justify-content: space-between; gap: 24px; padding: 23px 0; list-style: none; cursor: pointer; font-size: 1rem; font-weight: 600; line-height: 1.55; }
.faq-list summary::-webkit-details-marker { display: none; }
.faq-list summary::after { content: '+'; font-size: 1.5rem; font-weight: 400; line-height: 1; color: var(--blue); flex-shrink: 0; }
.faq-list details[open] summary::after { content: '−'; }
.faq-list summary:focus-visible { outline: 3px solid var(--blue); outline-offset: 5px; }
.faq-list details > p { padding: 0 32px 24px 0; color: var(--body); font-size: 1rem; }
.faq-list a { color: var(--blue); text-decoration: underline; text-underline-offset: 3px; }
.contact { background: var(--blue); color: white; }
.contact-inner { display: flex; justify-content: space-between; align-items: center; gap: 80px; }
.contact-copy { max-width: 560px; }
.contact .eyebrow { color: #d5e4f4; margin-bottom: 19px; }
.contact h2 { font-size: clamp(2.125rem, 3.5vw, 3rem); margin-bottom: 24px; }
.contact-copy > p:last-child { color: #e4edf7; font-size: 1rem; max-width: 470px; }
.contact-action { display: flex; align-items: flex-start; flex-direction: column; width: 430px; max-width: 100%; flex-shrink: 0; gap: 25px; }
.contact-options { display: grid; grid-template-columns: minmax(0, 1fr) 144px; gap: 24px; width: 100%; align-items: start; }
.contact-buttons { display: flex; flex-direction: column; gap: 12px; }
.contact-buttons .button { gap: 14px; padding-inline: 16px; justify-content: space-between; }
.contact-qr { width: 144px; }
.contact-qr img { width: 100%; height: auto; background: white; }
.contact-qr figcaption { margin-top: 9px; font-size: .875rem; line-height: 1.5; color: #e4edf7; }
.button-contact-outline { color: white; border-color: #a8c3e0; }
.button-contact-outline:hover { background: var(--blue-dark); }
.contact-email { font-size: clamp(1.25rem, 2vw, 1.75rem); letter-spacing: -.02em; line-height: 1.4; }
.contact-email:hover { text-decoration: underline; text-underline-offset: 6px; }
.button-white { background: var(--white); color: var(--blue); }
.button-white:hover { background: #e5eef7; }
.factory-details { display: grid; grid-template-columns: 1.1fr 1.25fr .8fr; gap: 48px; margin-top: 64px; padding-top: 35px; border-top: 1px solid #6389b5; scroll-margin-top: 110px; }
.factory-details > div { min-width: 0; }
.factory-details h3 { font-size: .875rem; color: #d5e4f4; font-weight: 500; margin-bottom: 14px; }
.factory-name { font-size: 1.125rem; font-weight: 500; line-height: 1.6; }
.factory-details address { font-size: 1rem; font-style: normal; line-height: 1.7; }
.factory-name-zh, .factory-address-zh { margin-top: 10px; font-size: .875rem; color: #d5e4f4; line-height: 1.8; }
.factory-phones > div + div { margin-top: 17px; }
.factory-phones dt { font-size: .875rem; line-height: 1.6; color: #d5e4f4; margin-bottom: 3px; }
.factory-phones dd { margin: 0; font-size: 1rem; line-height: 1.6; }
.factory-phones a { display: inline-block; padding-block: 3px; white-space: nowrap; }
.factory-phones a:hover { text-decoration: underline; text-underline-offset: 4px; }
.site-footer { padding-block: 39px; }
.footer-inner { display: flex; align-items: center; justify-content: space-between; gap: 24px; }
.footer-brand img { width: 150px; height: auto; }
.footer-brand p { font-size: .8125rem; color: var(--body); margin-top: 12px; }
.copyright { font-size: .8125rem; color: var(--body); }
.footer-nav { display: flex; justify-content: center; flex-wrap: wrap; gap: 12px 22px; max-width: 430px; color: var(--body); font-size: .875rem; line-height: 1.6; }
.footer-nav a:hover { color: var(--blue); text-decoration: underline; text-underline-offset: 4px; }

@media (min-width: 1550px) {
  .hero-inner { min-height: 620px; }
  .hero-copy { padding-block: 92px; }
}
@media (max-width: 1100px) {
  .hero-inner { grid-template-columns: 51% 49%; }
  .hero-copy { padding-block: 66px; padding-right: 28px; }
  h1 { font-size: 3.15rem; }
  .hero-lead { font-size: 1.125rem; }
  .desktop-break { display: none; }
  .product-grid { gap: 23px; }
  .product-photo { height: auto; }
  .product h4 { min-height: 52px; }
  .about-inner { gap: 60px; }
  .brand-focus { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 25px 32px; }
  .faq-inner { gap: 48px; grid-template-columns: 1fr 1.6fr; }
  .factory-details { gap: 28px; }
  .configuration-inner { grid-template-columns: 1fr 1fr; gap: 40px; }
  .configuration-heading { grid-column: 1/-1; }
  .configuration-heading h2 { max-width: none; }
  .configuration-option { padding-left: 24px; }
  .classrooms-heading { align-items: flex-start; flex-direction: column; gap: 20px; }
  .classrooms-heading > p { flex: auto; max-width: 500px; }
  .classroom-grid { grid-template-columns: minmax(0, 1fr) minmax(0, 250px); gap: 27px; }
  .classroom-gallery { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 32px 27px; }
  .contact-inner { gap: 50px; }
  .battery-facts { gap: 14px; }
  .battery-facts > div + div { padding-left: 14px; }
}
@media (max-width: 800px) {
  .section-pad { padding-block: 72px; }
  .header-inner { min-height: 74px; }
  .brand img { width: 145px; }
  .main-nav { gap: 24px; }
  .hero-inner { grid-template-columns: 1fr; }
  .hero-copy { padding: 53px 0 46px; }
  h1 { font-size: clamp(2.875rem, 7vw, 3.5rem); }
  .hero-description { max-width: 490px; }
  .hero-visual { margin-inline: calc(-1 * var(--gutter)); height: 450px; }
  .hero-visual > img { object-position: 50% 57%; }
  .hero-visual figcaption { left: var(--gutter); right: var(--gutter); }
  .product-grid { grid-template-columns: 1fr; gap: 48px; }
  .product { display: grid; grid-template-columns: 44% 1fr; gap: 28px; align-items: start; padding-bottom: 44px; border-bottom: 1px solid var(--line); }
  .product:last-child { padding-bottom: 0; border-bottom: 0; }
  .product-photo { height: auto; aspect-ratio: 4/5; }
  .product-copy { padding-top: 0; }
  .product h4 { min-height: auto; }
  .product-category { font-size: .8125rem; }
  .about-inner { grid-template-columns: 1fr; gap: 28px; }
  .faq-inner { grid-template-columns: 1fr; gap: 32px; }
  .factory-details { grid-template-columns: 1fr 1fr; gap: 32px; }
  .factory-details > div:first-child { grid-column: 1/-1; }
  .footer-inner { flex-wrap: wrap; }
  .footer-nav { justify-content: flex-start; max-width: 360px; }
  .classroom-grid { grid-template-columns: 1fr; gap: 32px; }
  .classrooms { padding-top: 0; }
  .contact-inner { align-items: flex-start; flex-direction: column; gap: 40px; }
}
@media (max-width: 540px) {
  :root { --gutter: 24px; }
  html { scroll-padding-top: 86px; }
  .header-inner { min-height: 73px; gap: 15px; }
  .brand img { width: 132px; }
  .main-nav { gap: 20px; }
  .main-nav a { font-size: .875rem; }
  .main-nav .nav-contact { padding: 12px 0; border: 0; }
  .main-nav .nav-contact:hover { color: var(--blue-dark); background: transparent; }
  .hero-copy .eyebrow { font-size: .75rem; letter-spacing: .045em; max-width: 310px; margin-bottom: 22px; }
  .hero-copy { padding-block: 46px 39px; }
  h1 { font-size: clamp(2.55rem, 10.8vw, 3.1rem); line-height: 1.11; margin-bottom: 23px; }
  .hero-lead { font-size: 1.125rem; max-width: 305px; margin-bottom: 12px; }
  .hero-description { font-size: .9375rem; }
  .hero-actions { gap: 25px; margin-top: 26px; }
  .hero-visual { height: 390px; }
  .hero-caption { bottom: 22px; }
  .section-pad { padding-block: 62px; }
  .section-heading { margin-bottom: 29px; }
  .product { display: flex; gap: 0; padding-bottom: 40px; }
  .product-photo { width: 100%; aspect-ratio: 1; }
  .product-photo-system { aspect-ratio: .88; }
  .product-photo-system img { object-fit: contain; }
  .product-copy { padding-top: 23px; }
  .product h3 { font-size: 1.875rem; margin-bottom: 13px; }
  .product h4 { margin-bottom: 11px; }
  .feature-list { margin-top: 21px; }
  .battery-facts { gap: 29px; }
  .battery-facts > div + div { padding-left: 29px; }
  .configuration-inner { grid-template-columns: 1fr; gap: 34px; }
  .configuration-heading h2 { font-size: 2rem; }
  .configuration-heading { grid-column: auto; }
  .configuration-option { padding-left: 0; border-left: 0; border-top: 1px solid var(--line); padding-top: 24px; }
  .option-number { margin-bottom: 12px; }
  .classrooms-heading { padding-top: 37px; margin-bottom: 28px; }
  .brand-focus { grid-template-columns: 1fr; gap: 24px; margin-top: 30px; }
  .faq-list summary { gap: 20px; padding-block: 20px; }
  .faq-list details > p { padding-right: 0; }
  .factory-details { grid-template-columns: 1fr; gap: 30px; margin-top: 44px; padding-top: 30px; }
  .factory-details > div:first-child { grid-column: auto; }
  .classroom-gallery { grid-template-columns: 1fr; gap: 30px; margin-top: 34px; }
  .contact-options { grid-template-columns: 1fr; gap: 26px; }
  .contact-buttons { max-width: 320px; }
  .contact-copy > p:last-child { max-width: 330px; }
  .contact-email { font-size: 1.375rem; }
  .footer-inner { flex-direction: column; align-items: flex-start; gap: 26px; }
  .site-footer { padding-block: 33px; }
}
@media (max-width: 370px) {
  :root { --gutter: 18px; }
  .brand img { width: 115px; }
  .main-nav { gap: 15px; }
  .hero-copy .eyebrow { max-width: 270px; }
  h1 { font-size: 2.375rem; }
  .hero-actions { gap: 20px; }
  .button { padding-inline: 16px; gap: 16px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition-duration: .01ms !important; }
}