:root{--navy:#102B46;--blue:#165DDE;--ice:#E8F4FF;--ink:#34475A;--orange:#F76B38;--line:#CBD8E5}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:90px}body{margin:0;font-family:Arial,Helvetica,sans-serif;color:var(--navy);background:#fff;font-size:17px;line-height:1.6}a{color:inherit}button,a,input{touch-action:manipulation}button{font:inherit}a:focus-visible,button:focus-visible,summary:focus-visible,[tabindex]:focus-visible{outline:3px solid #165DDE;outline-offset:5px}button:disabled{cursor:not-allowed;opacity:.65}.skip{position:fixed;top:-80px;left:16px;z-index:100;background:#fff;padding:12px}.skip:focus{top:10px}header{height:86px;padding:0 5%;display:flex;align-items:center;justify-content:space-between;gap:25px;background:#fff;position:sticky;top:0;z-index:10;border-bottom:1px solid #e2e9f0}.brand{display:flex;align-items:center;gap:9px;text-decoration:none}.brand strong{font-size:28px;letter-spacing:-1px}.brand span{font-size:12px;border-left:1px solid var(--line);padding-left:10px;color:var(--ink)}header nav{display:flex;gap:30px}header nav a{text-decoration:none;font-size:14px;min-height:44px;display:flex;align-items:center}header nav a:hover,.ask:hover{color:var(--blue)}.nav-buy{padding:10px 18px;border:1px solid var(--navy);text-decoration:none;font-size:14px;font-weight:700;border-radius:5px}.nav-buy span{margin-left:12px}.hero{position:relative;background:#D4EAF4;min-height:680px;display:flex;align-items:center;overflow:hidden}.hero-photo{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;object-position:center}.hero:after{content:'';position:absolute;inset:0;background:linear-gradient(90deg,#e8f4fff5 0%,#e8f4ffde 28%,#e8f4ff00 62%);pointer-events:none}.hero-content{position:relative;z-index:1;margin:50px 0 60px 7%;max-width:570px}.product-type{font-size:14px;letter-spacing:.02em;margin-bottom:25px}.hero h1{font-size:clamp(58px,6.7vw,98px);line-height:.97;letter-spacing:-.065em;margin:0 0 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p{margin:0;font-size:13px}.fine{font-size:12px;line-height:1.6}.rhythm-heading{display:flex;justify-content:space-between;align-items:end;gap:50px;margin-bottom:45px}.rhythm-heading p{max-width:290px}.rhythm-layout{display:grid;grid-template-columns:.8fr 1.2fr;gap:60px}.mode-list{display:flex;flex-direction:column}.mode-list button{border:0;border-top:1px solid var(--line);border-left:3px solid transparent;background:#fff;text-align:left;padding:28px 24px;display:grid;grid-template-columns:28px 1fr;gap:5px 12px;cursor:pointer;color:var(--navy)}.mode-list button:last-child{border-bottom:1px solid var(--line)}.mode-list button[aria-selected=true]{border-left-color:var(--blue);background:#F2F7FF}.mode-list button:hover{background:#F2F7FF}.mode-list strong{font-size:25px}.mode-list span{font-size:12px;align-self:center;color:var(--blue)}.mode-list small{grid-column:2;font-size:14px;color:var(--ink)}.insight-panel{background:var(--navy);color:#fff;padding:30px 36px;border-radius:12px;position:relative;min-height:420px;overflow:hidden}.orbit{position:relative;height:220px;display:flex;justify-content:center;align-items:center}.orbit svg{position:absolute;height:260px;width:320px;inset:50% auto auto 50%;transform:translate(-50%,-50%);stroke:#4E6F8D;fill:none}.orbit svg path{stroke:#76C8FF;stroke-width:3}.orbit>span{font-size:24px;letter-spacing:3px;line-height:1.2;text-align:center;background:var(--navy);padding:12px;z-index:1}.orbit small{font-size:8px;letter-spacing:2px}.insight-copy>span{font-size:12px;color:#A6D8FF}.insight-copy h3{font-size:25px;letter-spacing:-.02em;line-height:1.2;margin:10px 0}.insight-copy p{color:#D4E4F2;font-size:15px;margin:0 0 25px}.panel-note{font-size:10px;color:#B8CEE1;margin:0}.connection{background:var(--ice)}.connection-inner{display:grid;grid-template-columns:1fr 1fr;gap:100px;align-items:center}.connection-inner>div>p{max-width:430px}.connection-note{font-size:13px;border-top:1px solid #A8C9E6;padding-top:20px}.connection-diagram{display:grid;grid-template-columns:1fr 70px 1fr;align-items:center;text-align:center}.device-chip,.app-chip{display:flex;flex-direction:column;align-items:center}.device-chip svg,.app-chip svg{width:120px;height:120px;stroke:var(--blue);fill:none;stroke-width:2}.device-chip svg rect:first-child{stroke-dasharray:2 2}.device-chip strong,.app-chip strong{font-size:18px}.device-chip span,.app-chip span{font-size:13px;color:var(--ink)}.connection-line{width:100%;color:var(--blue)}.connection-diagram>p{grid-column:1/-1;font-size:12px;margin:35px auto 0}.specifications{display:grid;grid-template-columns:1fr 1.1fr;gap:20px 90px}.specifications dl{margin:0}.specifications dl>div{display:grid;grid-template-columns:1fr 1fr;gap:15px;padding:15px 0;border-bottom:1px solid var(--line);font-size:14px}.specifications dt{color:var(--ink)}.specifications 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solid var(--line)}.faq summary{cursor:pointer;font-weight:700;padding:22px 4px;min-height:44px}.faq details p{font-size:15px;padding:0 4px 15px}footer{background:var(--navy);color:#fff;padding:50px 7%}footer .brand{font-size:28px;font-weight:700}footer .brand span{color:#D4E4F2;font-weight:400}footer p{color:#D4E4F2}footer nav{display:flex;gap:20px 30px;flex-wrap:wrap;font-size:14px;margin:25px 0}footer nav a{min-height:44px;display:flex;align-items:center}footer nav span{align-self:center}footer small{display:block;color:#BDCFDF;font-size:11px}img{max-width:100%}p,dd,a{overflow-wrap:anywhere}
@media(min-width:1600px){.hero{min-height:760px}.hero-photo{object-position:center 43%}}
@media(max-width:1023px){header{padding:0 25px}.brand span{display:none}header nav{gap:18px}.hero{min-height:610px}.hero-content{margin-left:5%;max-width:450px}.hero h1{font-size:72px}.section{padding:70px 30px}.intro,.connection-inner,.specifications,.shop-inner{gap:40px}.product-copy{padding:40px 9%}.product-copy h2{font-size:44px}.dimensions{gap:25px}.dimensions strong{font-size:48px}.rhythm-layout{gap:30px}.faq{gap:40px}.shop h2{font-size:36px}}
@media(max-width:767px){html{scroll-padding-top:72px}header{height:70px;padding:0 20px;gap:10px}.brand strong{font-size:25px}header nav{display:none}.nav-buy{padding:8px 12px;font-size:12px;min-height:44px;display:flex;align-items:center}.nav-buy span{margin-left:8px}.hero{min-height:0;padding-top:0;display:flex;flex-direction:column;align-items:stretch;background:#E8F4FF}.hero-photo{position:relative;order:1;height:430px;width:100%;object-position:65% center}.hero:after{display:none}.hero-content{order:0;margin:35px 24px 32px;max-width:none}.product-type{font-size:12px;margin:0 0 18px}.hero h1{font-size:64px;margin-bottom:20px}.hero-content>p:not(.product-type){font-size:18px;line-height:1.5;margin-bottom:24px}.hero-content .button{font-size:13px;width:100%;padding:13px}.hero-note{margin-top:23px;font-size:13px}.photo-note{font-size:9px;right:10px;bottom:10px}.promise-strip{grid-template-columns:1fr;padding:22px 24px;gap:10px;font-size:13px;text-align:left}.promise-strip span+span{border:0}.promise-strip span{display:flex;align-items:center;gap:12px}.promise-strip span:before{content:'';width:5px;height:5px;background:#83CFFF;border-radius:50%}.section{padding:56px 24px}.intro,.product-story,.connection-inner,.specifications,.shop-inner,.faq{grid-template-columns:1fr;gap:25px}.intro>p{font-size:17px;margin:0}h2{font-size:40px}.product-copy{padding:42px 24px}.product-copy h2{font-size:44px}.dimensions{gap:50px}.product-image img{aspect-ratio:1.1}.rhythm-heading{display:block;margin-bottom:25px}.rhythm-heading p{max-width:none}.rhythm-layout{grid-template-columns:1fr;gap:24px}.mode-list{flex-direction:row;border-bottom:1px solid var(--line)}.mode-list button{display:flex;flex:1;flex-direction:column;gap:0;padding:15px 5px;align-items:center;border-left:0;border-bottom:3px solid transparent;border-top:0}.mode-list button:last-child{border-bottom:3px solid transparent}.mode-list button[aria-selected=true]{border-bottom-color:var(--blue)}.mode-list small,.mode-list span{display:none}.mode-list strong{font-size:16px}.insight-panel{padding:24px;min-height:420px}.connection-inner{gap:35px}.connection-diagram{grid-template-columns:1fr 35px 1fr}.connection-note{font-size:12px}.spec-footnote{grid-column:1}.specifications dl>div{font-size:13px;grid-template-columns:.95fr 1.05fr}.shop-inner{gap:35px}.shop h2{font-size:36px}.faq{gap:10px}footer{padding:40px 24px}footer nav{display:grid;gap:8px}footer nav span{padding:10px 0}.faq summary{font-size:16px}.price{font-size:36px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}}
.hero-photo{object-position:center top}@media(max-width:767px){.hero h1{font-size:50px;letter-spacing:-.06em}.hero-photo{object-position:65% center}}

.brand strong{font-size:22px;letter-spacing:-.7px}footer .brand{font-size:24px}@media(max-width:767px){.brand strong{font-size:17px;letter-spacing:-.5px}.brand svg{width:23px;height:23px}.brand{gap:6px}.nav-buy{padding:8px 10px}}

/* Fixed contact controls: touch targets and independent focus states. */
.band-contact{position:fixed;right:16px;bottom:max(20px,env(safe-area-inset-bottom));z-index:80;display:flex;flex-direction:column;gap:10px;direction:ltr}.band-contact>a,.band-contact summary{display:flex;align-items:center;justify-content:center;width:48px;height:48px;box-sizing:border-box;background:#165DDE;color:#fff;border:1px solid #fff;border-radius:50%;cursor:pointer;box-shadow:0 2px 8px #165DDE26;text-decoration:none;list-style:none}.band-contact summary::-webkit-details-marker{display:none}.band-contact svg{width:24px;height:24px}.band-contact a:hover,.band-contact summary:hover{background:#1048AF}.band-contact a:active,.band-contact summary:active{background:#102B46}.band-contact a:focus-visible,.band-contact summary:focus-visible{outline:3px solid #165DDE;outline-offset:3px}.band-contact details{position:relative}.band-wechat{position:absolute;right:60px;bottom:0;min-width:180px;padding:16px;background:#fff;color:#24332F;border:1px solid #CBD7D0;border-radius:8px;box-shadow:0 2px 10px #165DDE26}.band-wechat strong,.band-wechat span{display:block}.band-wechat span{font-size:20px;user-select:all;margin-top:6px}@media(max-width:767px){.band-contact{right:10px;gap:8px}.band-contact>a,.band-contact summary{width:44px;height:44px}.band-wechat{right:54px;min-width:160px}.purchase #checkout{width:calc(100% - 50px)}footer{padding-right:65px}}

header .buytcn-brand{gap:14px}.buytcn-brand .logo-crop{display:block;position:relative;width:142px;height:40px;overflow:hidden;border:0;padding:0;flex-shrink:0}.logo-crop img{position:absolute;width:170px;height:170px;max-width:none;left:-14px;top:-64px}.buytcn-brand .band-brand-name{font-size:12px;display:block}.reading-progress{position:absolute;bottom:-1px;left:0;height:3px;background:#165DDE;width:100%;transform:scaleX(0);transform-origin:left;pointer-events:none}.band-contact .band-wechat{font-family:Arial,sans-serif}.hero-content{animation:hero-enter .8s ease-out both}.hero-photo{animation:photo-settle 1.4s ease-out both}.insight-panel.is-switching .orbit svg path{stroke-dasharray:400;animation:trace 1.1s ease-out both}.insight-panel.is-switching .insight-copy{animation:insight-enter .35s ease-out both}@keyframes hero-enter{from{opacity:.3;clip-path:inset(0 0 15% 0)}to{opacity:1;clip-path:inset(0)}}@keyframes photo-settle{from{transform:scale(1.025)}to{transform:scale(1)}}@keyframes trace{from{stroke-dashoffset:400}to{stroke-dashoffset:0}}@keyframes insight-enter{from{opacity:.4}to{opacity:1}}@media(max-width:767px){header .buytcn-brand{gap:0}.buytcn-brand .logo-crop{width:124px}.logo-crop img{left:-14px;width:155px;height:155px;top:-57px}.buytcn-brand .band-brand-name{display:none}.shop #checkout{width:calc(100% - 50px)}.shop .ask{margin-right:40px}}@media(prefers-reduced-motion:reduce){.hero-content,.hero-photo,.insight-panel.is-switching .orbit svg path,.insight-panel.is-switching .insight-copy{animation:none!important}.reading-progress{display:none}}

.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.product-showcase{display:grid;grid-template-columns:1.05fr 1fr;background:#F1F7FC;position:relative;max-width:1600px;margin:auto}.showcase-visual{position:sticky;top:86px;height:calc(100vh - 86px);min-height:560px;max-height:950px;align-self:start;display:flex;align-items:center;justify-content:center;overflow:hidden}.showcase-frame{position:relative;width:100%;height:100%;display:flex;flex-direction:column;align-items:center;justify-content:center}.showcase-frame img{width:100%;height:80%;object-fit:contain;mix-blend-mode:multiply;transform:scale(.88) rotate(-5deg);transition:transform .8s cubic-bezier(.2,.6,.3,1)}.showcase-visual[data-phase="1"] img{transform:scale(1.15) rotate(3deg)}.showcase-visual[data-phase="2"] img{transform:scale(.92) rotate(-2deg)}.showcase-caption{font-size:13px;margin:0}.showcase-frame nav{display:flex;gap:0;align-items:center;justify-content:center;margin:5px 0}.showcase-frame nav a{display:flex;width:44px;height:44px;align-items:center;justify-content:center}.showcase-frame nav a:after{content:'';width:6px;height:6px;border:1px solid #617E98;border-radius:50%}.showcase-frame nav a[aria-current]:after{background:#165DDE;border-color:#165DDE;box-shadow:0 0 0 4px #165DDE15}.showcase-frame>small{position:absolute;bottom:12px;left:22px;font-size:10px;color:#34475A}.showcase-chapters article{min-height:83vh;padding:90px 60px 90px 25px;display:flex;flex-direction:column;justify-content:center;scroll-margin-top:90px}.showcase-chapters h2{font-size:clamp(38px,4.3vw,66px)}.showcase-chapters article>p:not(.section-index){max-width:460px;font-size:18px}.detail-link{font-size:14px;font-weight:700;color:#165DDE;padding:10px 0;min-height:44px;width:max-content;max-width:100%}.showcase-measures{display:flex;gap:38px;margin:20px 0}.showcase-measures strong{font-size:60px;letter-spacing:-3px;line-height:1.2;font-weight:600;font-variant-numeric:tabular-nums}.showcase-measures strong span{font-size:18px;letter-spacing:0;margin-left:3px}.showcase-measures p{font-size:12px;margin:8px 0}.showcase-chapters small{font-size:11px;max-width:430px;color:#34475A}@media(max-width:1023px){.showcase-chapters article{padding-right:30px}.showcase-measures{gap:24px}.showcase-measures strong{font-size:48px}.showcase-chapters h2{font-size:42px}}@media(max-width:767px){.product-showcase{display:block}.showcase-visual{position:relative;top:0;height:480px;min-height:0}.showcase-frame img{height:80%;width:100%;max-width:450px;transform:none!important}.showcase-frame nav{display:none}.showcase-caption{margin:12px 0 0}.showcase-chapters article{min-height:0;padding:45px 24px;border-top:1px solid #D2E1ED}.showcase-chapters h2{font-size:40px}.showcase-chapters article>p:not(.section-index){font-size:17px}.showcase-measures{gap:40px}.showcase-measures strong{font-size:50px}}@media(prefers-reduced-motion:reduce){.showcase-frame img{transition:none;transform:none!important}}
.showcase-frame img{transform:scale(.9)}.showcase-visual[data-phase="1"] img{transform:scale(1.12)}.showcase-visual[data-phase="2"] img{transform:scale(.96)}@media(max-width:767px){.showcase-frame img{transform:none!important}}