:root{
  --brand:#0f766e;--brand-d:#0a4f49;--brand-l:#14b8a6;--mint:#effcfa;--mint-2:#d8f5f0;
  --accent:#ff8a3d;--accent-d:#e8691a;--gold:#f5c542;
  --ink:#0f2a2e;--ink-2:#41585c;--ink-3:#6b8084;--line:#dcebe9;--card:#fff;--bg:#fbfefd;
  --r-s:12px;--r-m:20px;--r-l:28px;
  --sh-1:0 1px 2px rgba(15,42,46,.06),0 4px 14px rgba(15,42,46,.06);
  --sh-2:0 2px 4px rgba(15,42,46,.06),0 18px 44px rgba(15,118,110,.16);
  --max:1160px;
  --font:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,"Noto Sans",sans-serif;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{margin:0;font:400 17px/1.6 var(--font);color:var(--ink);background:var(--bg);overflow-x:hidden}
img,video,svg{max-width:100%;display:block}
a{color:var(--brand);text-decoration:none}a:hover{text-decoration:underline}
h1,h2,h3{line-height:1.18;margin:0 0 .5em;letter-spacing:-.02em;color:var(--ink)}
h1{font-size:clamp(2.1rem,5.4vw,3.6rem);font-weight:850}
h2{font-size:clamp(1.65rem,3.6vw,2.4rem);font-weight:820}
h3{font-size:1.18rem;font-weight:760}
p{margin:0 0 1em}
.wrap{max-width:var(--max);margin:0 auto;padding:0 20px}
.skip{position:absolute;left:-999px;top:8px;background:#fff;padding:10px 14px;border-radius:10px;z-index:100}
.skip:focus{left:12px}
:focus-visible{outline:3px solid var(--brand-l);outline-offset:3px;border-radius:8px}
section{padding:72px 0}
.sec-head{max-width:720px;margin:0 auto 40px;text-align:center}
.sec-head p{color:var(--ink-2);font-size:1.08rem}
.eyebrow{display:inline-block;font-size:.82rem;font-weight:800;letter-spacing:.08em;text-transform:uppercase;color:var(--brand);background:var(--mint-2);padding:6px 12px;border-radius:999px;margin-bottom:14px}

/* Header */
.hdr{position:sticky;top:0;z-index:50;background:rgba(251,254,253,.88);backdrop-filter:saturate(1.4) blur(12px);-webkit-backdrop-filter:saturate(1.4) blur(12px);border-bottom:1px solid var(--line)}
.hdr .wrap{display:flex;align-items:center;gap:18px;height:68px}
.brand{display:flex;align-items:center;gap:10px;font-weight:850;font-size:1.2rem;color:var(--ink);letter-spacing:-.02em}
.brand:hover{text-decoration:none}
.brand img{width:38px;height:38px;border-radius:11px;box-shadow:var(--sh-1)}
.nav{display:flex;gap:4px;margin-left:auto;align-items:center}
.nav a{color:var(--ink-2);font-weight:650;font-size:.97rem;padding:9px 13px;border-radius:999px}
.nav a:hover{background:var(--mint-2);text-decoration:none;color:var(--brand-d)}
.nav a.btn-p,.nav a.btn-p:hover{color:#fff;background:var(--brand)}
.nav a.btn-p:hover{background:var(--brand-d)}
.nav a[aria-current="page"]{color:var(--brand-d);background:var(--mint-2)}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;font:750 1rem/1 var(--font);padding:15px 24px;border-radius:999px;border:0;cursor:pointer;transition:transform .15s ease,box-shadow .15s ease,background .15s;text-decoration:none!important;min-height:48px}
.btn-p{background:var(--brand);color:#fff;box-shadow:0 6px 18px rgba(15,118,110,.35)}
.btn-p:hover{background:var(--brand-d);transform:translateY(-2px);box-shadow:0 10px 24px rgba(15,118,110,.4)}
.btn-o{background:#fff;color:var(--brand-d);border:2px solid var(--line)}
.btn-o:hover{border-color:var(--brand-l);transform:translateY(-2px)}
.btn-a{background:var(--accent);color:#fff;box-shadow:0 6px 18px rgba(255,138,61,.4)}
.btn-a:hover{background:var(--accent-d);transform:translateY(-2px)}
.hdr .btn{padding:11px 20px;min-height:42px;font-size:.95rem}
.burger{display:none;margin-left:auto;background:none;border:0;width:46px;height:46px;border-radius:12px;cursor:pointer;color:var(--ink)}
.burger svg{margin:auto}

/* Hero */
.hero{overflow:hidden;padding:56px 0 40px;background:radial-gradient(1100px 520px at 85% -10%,var(--mint-2),transparent 60%),radial-gradient(700px 400px at -5% 20%,#fff1e4,transparent 60%)}
.hero .wrap{display:grid;grid-template-columns:1.08fr .92fr;gap:40px;align-items:center}
.hero p.lead{font-size:1.22rem;color:var(--ink-2);max-width:560px}
.hero h1 em{font-style:normal;color:var(--brand);background:linear-gradient(transparent 62%,rgba(245,197,66,.55) 62%)}
.cta-row{display:flex;gap:12px;flex-wrap:wrap;margin:26px 0 22px}
.chips{display:flex;flex-wrap:wrap;gap:10px 18px;color:var(--ink-2);font-size:.95rem;font-weight:600}
.chips span{display:flex;align-items:center;gap:7px}
.chips svg{width:18px;height:18px;color:var(--brand)}
.phones{position:relative;height:620px;display:flex;justify-content:center}
.phone{position:absolute;width:262px;border-radius:38px;background:#10272b;padding:9px;box-shadow:var(--sh-2)}
.phone img{border-radius:30px;width:100%;height:auto;aspect-ratio:390/844;object-fit:cover}
.phone.p1{left:50%;top:0;transform:translateX(-50%) rotate(0);z-index:3;width:290px}
.phone.p2{left:2%;top:70px;transform:rotate(-8deg);z-index:2;opacity:.98}
.phone.p3{right:2%;top:90px;transform:rotate(8deg);z-index:2}
.float{position:absolute;z-index:4;background:#fff;border-radius:16px;box-shadow:var(--sh-2);padding:10px 14px;font-weight:750;font-size:.9rem;display:flex;gap:8px;align-items:center;animation:bob 5s ease-in-out infinite}
.float.f1{left:-2%;bottom:120px}.float.f2{right:-2%;top:40px;animation-delay:-2s}
@keyframes bob{50%{transform:translateY(-8px)}}

/* Stats */
.stats{padding:0;margin-top:-6px}
.stats .grid{display:grid;grid-template-columns:repeat(4,1fr);gap:0;background:#fff;border:1px solid var(--line);border-radius:var(--r-l);box-shadow:var(--sh-1);overflow:hidden}
.stat{padding:26px 18px;text-align:center;border-right:1px solid var(--line)}
.stat:last-child{border-right:0}
.stat b{display:block;font-size:2.3rem;font-weight:850;color:var(--brand);line-height:1.1;letter-spacing:-.03em}
.stat span{color:var(--ink-2);font-size:.95rem;font-weight:600}

/* Language cards */
.lang-grid{display:grid;grid-template-columns:repeat(5,1fr);gap:14px}
.lang{display:flex;flex-direction:column;gap:6px;background:#fff;border:1px solid var(--line);border-radius:var(--r-m);padding:20px 16px;text-align:center;color:var(--ink);transition:transform .18s,box-shadow .18s,border-color .18s}
.lang:hover{transform:translateY(-4px);box-shadow:var(--sh-2);border-color:var(--brand-l);text-decoration:none}
.lang .flag{width:76px;height:50px;margin:0 auto 8px;border-radius:9px;box-shadow:0 0 0 1px rgba(15,42,46,.1),0 6px 14px rgba(15,42,46,.16);transition:transform .18s}.lang:hover .flag{transform:scale(1.07) rotate(-2deg)}
.flag-lg{width:72px;height:48px;border-radius:9px;box-shadow:0 0 0 1px rgba(15,42,46,.1),0 6px 14px rgba(15,42,46,.16)}
.flag-xs{width:24px;height:16px;border-radius:3px;box-shadow:0 0 0 1px rgba(15,42,46,.12);flex:0 0 auto}
.hero-flag{display:flex;align-items:center;gap:14px;margin-bottom:14px;flex-wrap:wrap}.hero-flag .eyebrow{margin:0}
.toc a:has(.flag-xs){display:inline-flex;align-items:center;gap:8px}
.lang .badge{width:54px;height:54px;border-radius:50%;margin:0 auto 6px;display:grid;place-items:center;font-weight:850;color:#fff;font-size:1.05rem;letter-spacing:.02em}
.lang strong{font-size:1.05rem}
.lang small{color:var(--ink-3);font-size:.9rem}
.lang .go{margin-top:6px;color:var(--brand);font-weight:700;font-size:.9rem}

/* Features */
.feat-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}
.feat{background:#fff;border:1px solid var(--line);border-radius:var(--r-m);padding:26px;box-shadow:var(--sh-1)}
.feat .ic{width:52px;height:52px;border-radius:15px;display:grid;place-items:center;font-size:1.6rem;margin-bottom:16px;background:var(--mint-2)}
.feat p{color:var(--ink-2);margin:0;font-size:.98rem}
.alt{background:linear-gradient(180deg,var(--mint),#fff)}

/* Steps */
.steps{display:grid;grid-template-columns:repeat(3,1fr);gap:22px;counter-reset:s}
.step{position:relative;background:#fff;border:1px solid var(--line);border-radius:var(--r-m);padding:28px 24px 24px}
.step::before{counter-increment:s;content:counter(s);position:absolute;top:-18px;left:22px;width:38px;height:38px;border-radius:50%;background:var(--brand);color:#fff;font-weight:850;display:grid;place-items:center;box-shadow:0 6px 14px rgba(15,118,110,.35)}
.step p{color:var(--ink-2);margin:0}

/* Gallery */
.gallery{display:flex;gap:22px;overflow-x:auto;padding:10px 20px 34px;scroll-snap-type:x mandatory;scrollbar-width:thin}
.gallery figure{margin:0;flex:0 0 auto;width:250px;scroll-snap-align:center;text-align:center}
.gallery .phone{position:static;width:100%}
.gallery figcaption{margin-top:14px;font-weight:700;color:var(--ink-2);font-size:.95rem}

/* Videos */
.vid-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:22px}
.vid{background:#fff;border:1px solid var(--line);border-radius:var(--r-m);overflow:hidden;box-shadow:var(--sh-1)}
.vid video{width:100%;aspect-ratio:390/844;object-fit:cover;background:#0b3b37;max-height:520px}
.vid .cap{padding:18px 20px 22px}
.vid .cap p{color:var(--ink-2);font-size:.95rem;margin:0}
.vid-big{display:grid;grid-template-columns:320px 1fr;gap:34px;align-items:center;background:#fff;border:1px solid var(--line);border-radius:var(--r-l);padding:26px;box-shadow:var(--sh-1);margin-bottom:26px}
.vid-big video{width:100%;aspect-ratio:390/844;object-fit:cover;border-radius:22px;background:#0b3b37}

/* Demo (nghe thử) */
.demo{background:linear-gradient(135deg,var(--brand-d),var(--brand));color:#fff;border-radius:var(--r-l);padding:44px;display:grid;grid-template-columns:1fr 1fr;gap:34px;align-items:center;box-shadow:var(--sh-2)}
.demo h2,.demo h3{color:#fff}
.demo p{color:#d5f5f0}
.demo .words{display:grid;gap:10px}
.word{display:flex;align-items:center;gap:12px;background:#fff;color:var(--ink);border-radius:16px;padding:12px 14px}
.word .t{font-weight:800;font-size:1.08rem;line-height:1.25}
.word .r{display:block;font-weight:500;font-size:.85rem;color:var(--ink-3)}
.word .v{margin-left:auto;color:var(--ink-2);font-weight:600;text-align:right}

/* Play button */
.say{flex:0 0 auto;width:44px;height:44px;border-radius:50%;border:0;background:var(--mint-2);color:var(--brand-d);cursor:pointer;display:grid;place-items:center;transition:background .15s,transform .15s}
.say:hover{background:var(--brand-l);color:#fff;transform:scale(1.06)}
.say svg{width:20px;height:20px}
.say[data-s="loading"]{opacity:.6;cursor:progress}
.say[data-s="play"]{background:var(--brand);color:#fff}
.say[data-s="err"]{background:#ffe3e0;color:#b3261e}

/* FAQ */
.faq{max-width:820px;margin:0 auto;display:grid;gap:12px}
.faq details{background:#fff;border:1px solid var(--line);border-radius:var(--r-m);padding:4px 22px}
.faq summary{cursor:pointer;font-weight:750;padding:16px 0;list-style:none;display:flex;justify-content:space-between;gap:14px;align-items:center}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"+";font-size:1.5rem;color:var(--brand);font-weight:500;transition:transform .2s}
.faq details[open] summary::after{transform:rotate(45deg)}
.faq details p{color:var(--ink-2);margin:0 0 16px}

/* CTA band */
.cta-band{background:linear-gradient(135deg,var(--brand-d),var(--brand));border-radius:var(--r-l);padding:56px 28px;text-align:center;color:#fff;position:relative;overflow:hidden}
.cta-band h2{color:#fff}.cta-band p{color:#cdf3ee;max-width:560px;margin:0 auto 26px}
.cta-band img{position:absolute;right:4%;bottom:-6px;width:130px;opacity:.95}
.cta-band .btn-a{font-size:1.08rem;padding:17px 30px}

/* Page header (inner pages) */
.page-hero{padding:46px 0 30px;background:radial-gradient(900px 360px at 90% -20%,var(--mint-2),transparent 60%)}
.crumbs{font-size:.9rem;color:var(--ink-3);margin-bottom:14px}
.crumbs a{color:var(--ink-3)}.crumbs a:hover{color:var(--brand)}
.crumbs span{margin:0 6px}
.page-hero p.lead{color:var(--ink-2);font-size:1.12rem;max-width:720px}
.layout{display:grid;grid-template-columns:1fr 300px;gap:34px;align-items:start}
.card{background:#fff;border:1px solid var(--line);border-radius:var(--r-m);padding:24px;box-shadow:var(--sh-1)}
.side{position:sticky;top:90px;display:grid;gap:16px}
.side .card h3{margin-bottom:.4em}
.level-cards{display:grid;grid-template-columns:repeat(4,1fr);gap:14px}
.lv{display:block;background:#fff;border:1px solid var(--line);border-radius:var(--r-m);padding:20px;color:var(--ink);transition:.18s}
.lv:hover{transform:translateY(-3px);box-shadow:var(--sh-2);border-color:var(--brand-l);text-decoration:none}
.lv b{display:block;color:var(--brand);font-size:.85rem;letter-spacing:.06em;text-transform:uppercase}
.lv strong{display:block;font-size:1.2rem;margin:4px 0 6px}
.lv small{color:var(--ink-2);display:block;font-size:.9rem;line-height:1.45}
.lv .n{margin-top:12px;color:var(--ink-3);font-size:.85rem;font-weight:650}
.group{margin-bottom:34px}
.group h3{display:flex;gap:10px;align-items:center}
.tiles{display:grid;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));gap:12px}
.tile{display:block;background:#fff;border:1px solid var(--line);border-radius:var(--r-m);padding:16px 18px;color:var(--ink);transition:.16s}
.tile:hover{border-color:var(--brand-l);box-shadow:var(--sh-1);transform:translateY(-2px);text-decoration:none}
.tile b{display:block}.tile small{color:var(--ink-2);display:block;margin-top:4px;line-height:1.4}
.lesson{margin-bottom:26px;scroll-margin-top:90px}
.lesson>h3{display:flex;align-items:baseline;gap:10px}
.lesson>h3 small{font-weight:700;color:var(--brand);font-size:.82rem;letter-spacing:.05em}
.wl{display:grid;gap:8px}
.dlg{display:grid;gap:10px}
.line{display:flex;gap:12px;align-items:center;padding:12px 14px;border-radius:16px;background:var(--mint)}
.line.me{background:#fff3e6;flex-direction:row-reverse;text-align:right}
.line .who{display:block;font-size:.78rem;font-weight:800;text-transform:uppercase;letter-spacing:.06em;color:var(--brand)}
.line.me .who{color:var(--accent-d)}
.line .t{font-weight:750;font-size:1.05rem}
.line .r{display:block;color:var(--ink-3);font-size:.85rem}
.line .v{display:block;color:var(--ink-2);font-size:.93rem}
.pager{display:flex;justify-content:space-between;gap:12px;margin-top:30px;flex-wrap:wrap}
.pager a{flex:1;min-width:200px;background:#fff;border:1px solid var(--line);border-radius:var(--r-m);padding:14px 18px;color:var(--ink)}
.pager a:hover{border-color:var(--brand-l);text-decoration:none}
.pager small{display:block;color:var(--ink-3);font-weight:700;font-size:.8rem;text-transform:uppercase;letter-spacing:.05em}
.pager .nx{text-align:right}
.toc{display:flex;flex-wrap:wrap;gap:8px;margin:0 0 26px}
.toc a{background:#fff;border:1px solid var(--line);border-radius:999px;padding:6px 14px;font-size:.88rem;font-weight:700;color:var(--ink-2)}
.toc a:hover{border-color:var(--brand-l);color:var(--brand-d);text-decoration:none}
.play-all{margin-bottom:14px}

/* Footer */
.ftr{background:#0b2a2c;color:#b9d3d2;padding:56px 0 30px;margin-top:40px}
.ftr a{color:#d7ecea}.ftr h4{color:#fff;margin:0 0 14px;font-size:1rem}
.ftr .cols{display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr;gap:34px}
.ftr ul{list-style:none;margin:0;padding:0;display:grid;gap:9px;font-size:.95rem}
.ftr .brand{color:#fff;margin-bottom:12px}
.ftr .small{border-top:1px solid #1d4648;margin-top:36px;padding-top:22px;font-size:.88rem;color:#8fb1b0;display:flex;gap:14px;justify-content:space-between;flex-wrap:wrap}

/* Responsive */
@media (max-width:980px){
  .hero .wrap{grid-template-columns:1fr;text-align:center}
  .hero p.lead{margin:0 auto}.cta-row,.chips{justify-content:center}
  .phones{height:560px;margin-top:10px}
  .lang-grid{grid-template-columns:repeat(3,1fr)}
  .feat-grid,.vid-grid{grid-template-columns:1fr 1fr}
  .steps{grid-template-columns:1fr;gap:30px}
  .demo{grid-template-columns:1fr;padding:30px}
  .layout{grid-template-columns:1fr}.side{position:static}
  .level-cards{grid-template-columns:1fr 1fr}
  .vid-big{grid-template-columns:1fr}.vid-big video{max-width:300px;margin:0 auto}
  .ftr .cols{grid-template-columns:1fr 1fr}
  .stats .grid{grid-template-columns:1fr 1fr}.stat:nth-child(2){border-right:0}.stat:nth-child(-n+2){border-bottom:1px solid var(--line)}
}
@media (max-width:760px){
  .burger{display:grid}
  .nav{position:absolute;left:0;right:0;top:68px;background:#fff;flex-direction:column;align-items:stretch;padding:12px 20px 20px;border-bottom:1px solid var(--line);box-shadow:var(--sh-2);display:none}
  .nav.open{display:flex}.nav a{padding:14px 16px}.hdr .btn{margin-top:6px}
}
@media (max-width:560px){
  body{font-size:16px}section{padding:52px 0}
  .lang-grid{grid-template-columns:1fr 1fr}
  .feat-grid,.vid-grid,.level-cards{grid-template-columns:1fr}
  .phones{height:500px}.phone{width:200px}.phone.p1{width:230px}
  .phone.p2{left:-4%}.phone.p3{right:-4%}.float{display:none}
  .stat b{font-size:1.9rem}
  .ftr .cols{grid-template-columns:1fr}
  .cta-band img{display:none}
}
@media (prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important;scroll-behavior:auto!important}}

.tile.locked{background:#fbfcfc}.tile.locked b{color:var(--ink-2)}
.lockcard{text-align:center;padding:40px 28px}.lockic{font-size:2.6rem;margin-bottom:6px}