/* ==========================================================================
   PianoAIS — www.pianoais.com
   Design tokens follow the A4 4P brochure (navy / blue / sky / gold).
   Bilingual: .lang-zh / .lang-en switched by html[data-lang].
   ========================================================================== */

:root{
  --navy:#043A78;
  --navy-2:#062c58;
  --blue:#0080C8;
  --sky:#7FC4EA;
  --sky-tx:#4FA0D8;
  --gold:#C9A227;
  --ink:#1D2530;
  --body:#5A6472;
  --mut:#8A93A0;
  --line:#E3E8EF;
  --soft:#F3F6FA;
  --serif:Georgia,"Times New Roman","Songti SC","SimSun",serif;
  --latin:Georgia,"Times New Roman",serif;
  --sans:"Segoe UI","Helvetica Neue",Arial,"PingFang SC","Microsoft YaHei",sans-serif;
}

*{margin:0;padding:0;box-sizing:border-box;}
html{scroll-behavior:smooth;}
body{font-family:var(--sans);color:var(--ink);background:#fff;-webkit-font-smoothing:antialiased;overflow-x:hidden;}
img{display:block;max-width:100%;}
a{text-decoration:none;color:inherit;}
.wrap{max-width:1180px;margin:0 auto;padding:0 24px;}

/* ---------- language switching ---------- */
html[data-lang="en"] .lang-zh{display:none !important;}
html[data-lang="zh"] .lang-en{display:none !important;}

/* ---------- header ---------- */
header{position:fixed;top:0;left:0;right:0;z-index:100;transition:all .35s ease;}
header .bar{display:flex;align-items:center;justify-content:space-between;height:76px;gap:18px;}
header.scrolled{background:rgba(255,255,255,.96);box-shadow:0 2px 18px rgba(4,58,120,.10);backdrop-filter:blur(10px);}
header.scrolled .bar{height:62px;}
.logo img{height:40px;width:auto;transition:height .35s;}
header.scrolled .logo img{height:32px;}
header.onhero:not(.scrolled) .logo img.logo-n{display:none;}
header.onhero:not(.scrolled) .logo img.logo-w{display:block;}
.logo img.logo-w{display:none;}

.nav-right{display:flex;align-items:center;gap:26px;}
nav.main{display:flex;gap:30px;align-items:center;}
nav.main a{font-size:14.5px;font-weight:600;letter-spacing:.6px;color:#fff;position:relative;padding:6px 0;transition:color .3s;white-space:nowrap;}
header.scrolled nav.main a{color:var(--ink);}
nav.main a:hover{color:var(--sky);}
header.scrolled nav.main a:hover{color:var(--blue);}
nav.main a::after{content:"";position:absolute;left:0;bottom:0;width:0;height:2px;background:var(--blue);transition:width .3s;}
nav.main a:hover::after{width:100%;}
nav.main a.active::after{width:100%;}
.nav-cta{background:var(--blue);color:#fff !important;padding:10px 20px !important;border-radius:999px;font-size:13.5px !important;transition:all .3s;}
.nav-cta::after{display:none;}
.nav-cta:hover{background:var(--navy);transform:translateY(-1px);}
header.scrolled .nav-cta{background:var(--blue);color:#fff !important;}

/* language switch */
.lang-switch{display:inline-flex;align-items:center;border:1.4px solid rgba(255,255,255,.55);border-radius:999px;overflow:hidden;flex:0 0 auto;}
header.scrolled .lang-switch{border-color:#D3DFEC;}
.lang-switch button{
  background:none;border:none;cursor:pointer;font-family:var(--sans);
  padding:7px 14px;font-size:12.5px;font-weight:700;letter-spacing:.8px;
  color:rgba(255,255,255,.82);transition:all .25s;
}
header.scrolled .lang-switch button{color:var(--mut);}
.lang-switch button.on{background:var(--blue);color:#fff;}
header.scrolled .lang-switch button.on{background:var(--blue);color:#fff;}

.burger{display:none;flex-direction:column;gap:5px;background:none;border:none;cursor:pointer;padding:8px;}
.burger span{width:24px;height:2.5px;background:#fff;border-radius:2px;transition:.3s;}
header.scrolled .burger span{background:var(--navy);}

@media(max-width:1000px){
  .nav-right{gap:14px;}
  nav.main{gap:22px;}
  nav.main a{font-size:13.5px;}
}
@media(max-width:900px){
  nav.main{position:fixed;top:0;right:-320px;width:300px;height:100vh;background:#fff;flex-direction:column;justify-content:center;gap:26px;box-shadow:-6px 0 30px rgba(0,0,0,.12);transition:right .35s;z-index:105;}
  nav.main.open{right:0;}
  nav.main a{color:var(--ink) !important;font-size:16px;}
  .burger{display:flex;position:relative;z-index:110;}
  header.onhero .burger span{background:#fff;}
  header.scrolled .burger span{background:var(--navy);}
}

/* ---------- hero ---------- */
.hero{position:relative;min-height:100vh;display:flex;align-items:flex-end;color:#fff;overflow:hidden;}
.hero .bg{position:absolute;inset:0;}
.hero .bg img{width:100%;height:100%;object-fit:cover;animation:heroZoom 14s ease-out forwards;}
@keyframes heroZoom{from{transform:scale(1.09);}to{transform:scale(1);}}
.hero::before{content:"";position:absolute;inset:0;background:linear-gradient(180deg,rgba(4,30,60,.34) 0%,rgba(4,30,60,.10) 40%,rgba(3,22,44,.78) 100%);}
.hero-inner{position:relative;z-index:2;width:100%;padding:0 24px 92px;max-width:1180px;margin:0 auto;}
.kicker{font-family:var(--latin);font-style:italic;font-size:clamp(14px,1.5vw,18px);color:var(--sky);letter-spacing:2.5px;text-transform:uppercase;}
.kicker::before{content:"";display:inline-block;width:34px;height:1.5px;background:var(--sky);vertical-align:middle;margin-right:14px;}
.hero h1{font-family:var(--serif);font-weight:700;font-size:clamp(40px,6.6vw,80px);line-height:1.08;margin:14px 0 20px;text-shadow:0 4px 30px rgba(0,0,0,.35);}
.hero h1 em{font-style:italic;color:var(--sky);}
.hero p.sub{max-width:580px;font-size:clamp(15px,1.6vw,18px);line-height:1.75;color:rgba(255,255,255,.92);margin-bottom:34px;}
.hero-btns{display:flex;gap:16px;flex-wrap:wrap;}
.btn{display:inline-flex;align-items:center;gap:10px;padding:15px 32px;border-radius:999px;font-weight:600;font-size:15px;letter-spacing:.4px;transition:all .3s;cursor:pointer;border:none;font-family:var(--sans);}
.btn-primary{background:var(--blue);color:#fff;box-shadow:0 10px 28px rgba(0,128,200,.42);}
.btn-primary:hover{background:#fff;color:var(--navy);transform:translateY(-2px);}
.btn-ghost{border:1.6px solid rgba(255,255,255,.65);color:#fff;background:transparent;}
.btn-ghost:hover{background:rgba(255,255,255,.14);transform:translateY(-2px);}
.hero-foot{position:absolute;bottom:26px;left:0;right:0;z-index:2;}
.hero-foot .wrap{display:flex;justify-content:center;}
.scroll-hint{display:flex;flex-direction:column;align-items:center;gap:8px;color:rgba(255,255,255,.75);font-size:11px;letter-spacing:2.5px;text-transform:uppercase;}
.scroll-hint i{display:block;width:1.5px;height:34px;background:linear-gradient(180deg,rgba(255,255,255,.8),transparent);animation:drop 1.8s infinite;}
@keyframes drop{0%{transform:scaleY(0);transform-origin:top;}50%{transform:scaleY(1);transform-origin:top;}51%{transform-origin:bottom;}100%{transform:scaleY(0);transform-origin:bottom;}}

/* ---------- page hero (inner pages) ---------- */
.phero{position:relative;min-height:56vh;display:flex;align-items:flex-end;color:#fff;overflow:hidden;padding-top:76px;}
.phero .bg{position:absolute;inset:0;}
.phero .bg img{width:100%;height:100%;object-fit:cover;}
.phero::before{content:"";position:absolute;inset:0;background:linear-gradient(180deg,rgba(4,30,60,.62) 0%,rgba(4,30,60,.36) 42%,rgba(3,22,44,.86) 100%);}
.phero .inner{position:relative;z-index:2;width:100%;max-width:1180px;margin:0 auto;padding:0 24px 62px;}
.phero h1{font-family:var(--serif);font-weight:700;font-size:clamp(32px,5vw,58px);line-height:1.1;margin:12px 0 14px;text-shadow:0 4px 26px rgba(0,0,0,.35);}
.phero h1 em{font-style:italic;color:var(--sky);}
.phero p.lead{max-width:620px;font-size:clamp(14.5px,1.5vw,17px);line-height:1.75;color:rgba(255,255,255,.9);}
.crumb{font-size:12px;letter-spacing:2px;text-transform:uppercase;color:rgba(255,255,255,.62);margin-bottom:4px;}

/* ---------- section base ---------- */
section{padding:96px 0;}
.section-tight{padding:70px 0;}
.sec-head{max-width:660px;margin-bottom:54px;}
.sec-head.center{margin-left:auto;margin-right:auto;text-align:center;}
.sec-head.center .kicker::before{display:none;}
.eyebrow{font-family:var(--latin);font-style:italic;font-size:17px;color:var(--blue);letter-spacing:1px;}
h2.title{font-family:var(--serif);font-weight:700;font-size:clamp(28px,3.8vw,42px);color:var(--navy);line-height:1.15;margin:10px 0 14px;}
h2.title .bl{color:var(--blue);}
.sec-sub{font-size:16px;line-height:1.8;color:var(--body);}
.dark{background:var(--navy-2);color:#fff;}
.dark h2.title{color:#fff;}
.dark .sec-sub{color:rgba(255,255,255,.78);}
.dark .eyebrow{color:var(--sky);}

/* ---------- stats band ---------- */
.stats{background:var(--soft);padding:44px 0;border-bottom:1px solid var(--line);}
.stats .wrap{display:grid;grid-template-columns:repeat(4,1fr);gap:20px;}
.stat{text-align:center;position:relative;}
.stat + .stat::before{content:"";position:absolute;left:0;top:14%;height:72%;width:1px;background:var(--line);}
.stat b{display:block;font-family:var(--latin);font-size:clamp(28px,3.4vw,40px);color:var(--blue);font-weight:700;}
.stat span{font-size:13px;color:var(--mut);letter-spacing:1.4px;text-transform:uppercase;}
@media(max-width:760px){
  .stats .wrap{grid-template-columns:repeat(2,1fr);gap:28px;}
  .stat:nth-child(3)::before{display:none;}
}

/* ---------- values ---------- */
.values{display:grid;grid-template-columns:repeat(3,1fr);gap:26px;}
.value{background:#fff;border:1px solid var(--line);border-radius:18px;padding:34px 30px;position:relative;transition:all .35s;}
.value:hover{transform:translateY(-6px);box-shadow:0 20px 44px rgba(4,58,120,.13);border-color:transparent;}
.value .num{font-family:var(--latin);font-style:italic;font-size:15px;color:var(--sky-tx);letter-spacing:1px;}
.value h3{font-family:var(--serif);font-size:21px;color:var(--navy);margin:10px 0 12px;line-height:1.35;}
.value p{font-size:14.5px;line-height:1.75;color:var(--body);}
.value::after{content:"";position:absolute;left:30px;top:0;width:44px;height:3px;background:var(--blue);border-radius:0 0 3px 3px;}
@media(max-width:860px){.values{grid-template-columns:1fr;}}

/* ---------- scenarios ---------- */
.scen-hero{position:relative;border-radius:22px;overflow:hidden;margin-bottom:44px;min-height:300px;display:flex;align-items:flex-end;}
.scen-hero img{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;}
.scen-hero::before{content:"";position:absolute;inset:0;background:linear-gradient(90deg,rgba(4,44,88,.86) 0%,rgba(4,44,88,.55) 45%,rgba(4,44,88,.05) 100%);}
.scen-hero .txt{position:relative;z-index:2;padding:38px 42px;color:#fff;max-width:640px;}
.scen-hero .txt em{font-family:var(--latin);font-style:italic;font-size:15px;color:var(--sky);}
.scen-hero .txt h3{font-family:var(--serif);font-size:clamp(22px,2.6vw,30px);margin:8px 0 10px;line-height:1.3;}
.scen-hero .txt p{font-size:14.5px;line-height:1.7;color:rgba(255,255,255,.88);}
.scen-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:26px;}
.scen{position:relative;border-radius:18px;overflow:hidden;height:340px;}
.scen img{width:100%;height:100%;object-fit:cover;transition:transform .6s ease;}
.scen:hover img{transform:scale(1.07);}
.scen::after{content:"";position:absolute;inset:0;background:linear-gradient(180deg,rgba(4,30,60,0) 34%,rgba(4,30,60,.88) 100%);}
.scen .info{position:absolute;left:0;right:0;bottom:0;z-index:2;padding:24px 26px;color:#fff;}
.scen .info .no{position:absolute;top:-58px;right:22px;font-family:var(--latin);font-style:italic;font-size:52px;color:rgba(255,255,255,.35);font-weight:700;}
.scen .info h4{font-family:var(--serif);font-size:20px;margin-bottom:4px;}
.scen .info .cat{font-size:12px;color:var(--sky);letter-spacing:1.6px;text-transform:uppercase;font-weight:600;}
.scen .info p{font-size:13.5px;line-height:1.65;color:rgba(255,255,255,.85);margin-top:10px;}
@media(max-width:960px){.scen-grid{grid-template-columns:repeat(2,1fr);}}
@media(max-width:620px){.scen-grid{grid-template-columns:1fr;}.scen{height:300px;}}

/* ---------- technology ---------- */
.tech-hero{position:relative;border-radius:22px;overflow:hidden;margin-bottom:50px;background:#0a1626;}
.tech-hero img{width:100%;height:clamp(260px,36vw,430px);object-fit:cover;opacity:.94;}
.tech-hero .cap{position:absolute;left:0;bottom:0;right:0;padding:30px 40px;background:linear-gradient(180deg,transparent,rgba(4,16,32,.88));color:#fff;}
.tech-hero .cap em{font-family:var(--latin);font-style:italic;font-size:14px;color:var(--sky);}
.tech-hero .cap h3{font-family:var(--serif);font-size:clamp(21px,2.6vw,30px);margin-top:6px;}
.feat-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:26px;}
.feat{background:#fff;border:1px solid var(--line);border-radius:18px;padding:30px 30px 26px;transition:all .35s;position:relative;overflow:hidden;}
.feat:hover{transform:translateY(-5px);box-shadow:0 20px 44px rgba(4,58,120,.12);}
.feat .fno{position:absolute;top:18px;right:24px;font-family:var(--latin);font-style:italic;font-size:40px;font-weight:700;color:#EAF2F9;line-height:1;transition:color .35s;}
.feat:hover .fno{color:var(--sky);}
.feat h3{font-family:var(--serif);font-size:21px;color:var(--navy);margin-bottom:12px;line-height:1.35;}
.feat h3 .no{color:var(--blue);font-size:15px;font-family:var(--sans);font-weight:700;margin-right:10px;}
.feat p{font-size:14.5px;line-height:1.75;color:var(--body);margin-bottom:16px;}
.chips{display:flex;flex-wrap:wrap;gap:8px;}
.chips > span{font-size:12.5px;font-weight:600;color:var(--blue);background:#EAF4FB;border:1px solid #D4E9F6;padding:6px 13px;border-radius:999px;line-height:1.4;}
@media(max-width:860px){.feat-grid{grid-template-columns:1fr;}}

/* ---------- dynamics band ---------- */
.dyn{position:relative;min-height:400px;display:flex;align-items:center;overflow:hidden;}
.dyn img{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;}
.dyn::before{content:"";position:absolute;inset:0;background:linear-gradient(90deg,rgba(4,30,60,.85) 0%,rgba(4,30,60,.45) 55%,rgba(4,30,60,.1) 100%);}
.dyn .txt{position:relative;z-index:2;color:#fff;padding:70px 24px;max-width:1180px;margin:0 auto;width:100%;}
.dyn .txt .inner{max-width:540px;}
.dyn h3{font-family:var(--serif);font-size:clamp(26px,3.4vw,38px);line-height:1.22;margin:12px 0 16px;}
.dyn h3 b{color:var(--sky);}
.dyn p{font-size:15.5px;line-height:1.8;color:rgba(255,255,255,.88);}
.dyn .bars{display:flex;gap:8px;margin-top:24px;}
.dyn .bars i{height:6px;border-radius:3px;background:linear-gradient(90deg,var(--blue),var(--sky));display:block;animation:pulse 2.4s ease-in-out infinite;}
.dyn .bars i:nth-child(1){width:46px;animation-delay:0s;}
.dyn .bars i:nth-child(2){width:78px;animation-delay:.15s;}
.dyn .bars i:nth-child(3){width:110px;animation-delay:.3s;}
.dyn .bars i:nth-child(4){width:64px;animation-delay:.45s;}
@keyframes pulse{0%,100%{opacity:.55;}50%{opacity:1;}}

/* ---------- spec table ---------- */
.spec-wrap{overflow-x:auto;border:1px solid var(--line);border-radius:18px;background:#fff;}
table.spec{width:100%;border-collapse:collapse;min-width:560px;}
table.spec th,table.spec td{padding:16px 22px;text-align:left;font-size:14.5px;border-bottom:1px solid var(--line);line-height:1.6;}
table.spec thead th{background:var(--soft);color:var(--navy);font-family:var(--serif);font-size:15px;letter-spacing:.4px;}
table.spec tbody tr:last-child td{border-bottom:none;}
table.spec tbody tr:hover{background:#F8FBFE;}
table.spec td:first-child{font-weight:600;color:var(--navy);white-space:nowrap;}

/* ---------- about ---------- */
.about-grid{display:grid;grid-template-columns:1.05fr .95fr;gap:56px;align-items:center;}
.about-txt p{font-size:15.5px;line-height:1.95;color:var(--body);margin-bottom:20px;}
.about-txt .quote{border-left:4px solid var(--blue);background:var(--soft);border-radius:0 14px 14px 0;padding:20px 26px;font-family:var(--serif);font-size:17px;color:var(--navy);line-height:1.75;}
.about-txt .quote b{color:var(--blue);}
.about-photos{display:flex;flex-direction:column;gap:18px;}
.about-photos .ph{border-radius:18px;overflow:hidden;box-shadow:0 16px 40px rgba(4,58,120,.14);}
.about-photos .ph img{width:100%;height:250px;object-fit:cover;transition:transform .6s;}
.about-photos .ph:hover img{transform:scale(1.04);}
@media(max-width:900px){.about-grid{grid-template-columns:1fr;gap:36px;}}

/* ---------- milestones ---------- */
.mile-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:24px;}
.mile{border:1px solid var(--line);border-radius:16px;padding:26px 24px;background:#fff;position:relative;}
.mile .mn{font-family:var(--latin);font-style:italic;font-size:13px;color:var(--sky-tx);letter-spacing:1px;}
.mile h4{font-family:var(--serif);font-size:18px;color:var(--navy);margin:8px 0 10px;line-height:1.35;}
.mile p{font-size:13.5px;line-height:1.7;color:var(--body);}
@media(max-width:960px){.mile-grid{grid-template-columns:repeat(2,1fr);}}
@media(max-width:560px){.mile-grid{grid-template-columns:1fr;}}

/* ---------- contact ---------- */
.contact-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:22px;margin-bottom:46px;}
.office{background:#fff;border:1px solid var(--line);border-radius:16px;padding:26px 24px;transition:all .35s;}
.office:hover{transform:translateY(-5px);box-shadow:0 18px 40px rgba(4,58,120,.12);}
.office .ono{font-size:12px;font-weight:700;color:var(--blue);letter-spacing:2px;}
.office h4{font-family:var(--serif);font-size:20px;color:var(--navy);margin:8px 0 2px;}
.office .city{font-family:var(--latin);font-style:italic;font-size:13.5px;color:var(--sky-tx);margin-bottom:14px;}
.office p{font-size:13.5px;line-height:1.7;color:var(--body);}
.office .tel{display:inline-block;margin-top:14px;font-weight:700;font-size:14.5px;color:var(--blue);border-top:1px solid var(--line);padding-top:12px;width:100%;}
.channels{display:grid;grid-template-columns:1fr 1fr;gap:22px;}
.chan{display:flex;align-items:center;gap:24px;background:var(--navy-2);border-radius:18px;padding:26px 32px;color:#fff;}
.chan.qr img{width:104px;height:104px;border-radius:12px;background:#fff;padding:5px;flex:0 0 auto;}
.chan .ct h4{font-family:var(--serif);font-size:19px;margin-bottom:8px;}
.chan .ct p{font-size:13.5px;color:rgba(255,255,255,.78);line-height:1.7;margin-bottom:6px;}
.chan .ct a{color:var(--sky);font-weight:600;font-size:14.5px;transition:color .3s;}
.chan .ct a:hover{color:#fff;}
@media(max-width:960px){.contact-grid{grid-template-columns:repeat(2,1fr);}.channels{grid-template-columns:1fr;}}
@media(max-width:600px){.contact-grid{grid-template-columns:1fr;}.chan{flex-direction:column;text-align:center;}}

/* ---------- CTA strip ---------- */
.cta-strip{background:var(--navy);border-radius:22px;padding:46px 48px;color:#fff;display:flex;align-items:center;justify-content:space-between;gap:30px;flex-wrap:wrap;}
.cta-strip .ct{max-width:560px;}
.cta-strip h3{font-family:var(--serif);font-size:clamp(22px,2.8vw,30px);line-height:1.3;margin-bottom:10px;}
.cta-strip h3 b{color:var(--sky);}
.cta-strip p{font-size:14.5px;line-height:1.75;color:rgba(255,255,255,.82);}
.btn-light{background:#fff;color:var(--navy);}
.btn-light:hover{background:var(--sky);color:var(--navy);transform:translateY(-2px);}

/* ---------- footer ---------- */
footer{background:#031d3d;color:rgba(255,255,255,.66);padding:56px 0 30px;}
.f-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr 1.2fr;gap:38px;padding-bottom:34px;border-bottom:1px solid rgba(255,255,255,.12);}
.f-grid img{height:38px;margin-bottom:16px;}
.f-grid h5{color:#fff;font-family:var(--serif);font-size:15.5px;margin-bottom:14px;letter-spacing:.4px;}
.f-grid p{font-size:13.5px;line-height:1.85;}
.f-list{display:flex;flex-direction:column;gap:9px;font-size:13.5px;}
.f-list a{transition:color .3s;}
.f-list a:hover{color:var(--sky);}
.f-bottom{padding-top:24px;display:flex;justify-content:space-between;gap:14px;flex-wrap:wrap;font-size:12.5px;color:rgba(255,255,255,.42);}
.f-bottom em{font-family:var(--latin);font-style:italic;color:rgba(255,255,255,.55);}
@media(max-width:960px){.f-grid{grid-template-columns:1fr 1fr;gap:30px;}}
@media(max-width:560px){.f-grid{grid-template-columns:1fr;}}

/* ---------- float whatsapp / back-to-top ---------- */
.float-wa{position:fixed;right:22px;bottom:22px;z-index:90;width:56px;height:56px;border-radius:50%;background:#25D366;display:flex;align-items:center;justify-content:center;box-shadow:0 10px 26px rgba(37,211,102,.45);transition:transform .3s;}
.float-wa:hover{transform:scale(1.1);}
.float-wa svg{width:29px;height:29px;fill:#fff;}

/* ---------- reveal ---------- */
.rv{opacity:0;transform:translateY(34px);transition:opacity .8s ease,transform .8s ease;}
.rv.in{opacity:1;transform:none;}
.rv.d1{transition-delay:.12s;}.rv.d2{transition-delay:.24s;}.rv.d3{transition-delay:.36s;}
@media(prefers-reduced-motion:reduce){
  .rv{opacity:1;transform:none;transition:none;}
  .hero .bg img{animation:none;}
}