:root{
  --ink:#0f1b2d; --muted:#5a6678; --line:#e4e1d8; --bg:#fbfaf6; --alt:#f2efe7; --card:#ffffff;
  --p:#0f7b6c; --pd:#0a5a4f; --soft:#e2f2ee; --a:#e9a23b; --dark:#0f1b2d; --on-dark:#eaf0f7;
  --r:16px; --sh:0 10px 30px rgba(15,27,45,.08);
  --font:"Be Vietnam Pro",system-ui,-apple-system,"Segoe UI",Roboto,Arial,sans-serif;
}
@media (prefers-color-scheme:dark){
  :root{--ink:#eef2f7; --muted:#a3afc0; --line:#27344a; --bg:#0b1422; --alt:#101c2e; --card:#14233a;
    --p:#35c4a8; --pd:#7fe0cb; --soft:#12353a; --sh:0 10px 30px rgba(0,0,0,.35); --dark:#060d18;}
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:76px}
body{margin:0;font:16px/1.65 var(--font);color:var(--ink);background:var(--bg);-webkit-font-smoothing:antialiased}
img,svg{max-width:100%}
a{color:inherit}
.wrap{width:min(1160px,100% - 32px);margin-inline:auto}
h1,h2,h3{line-height:1.2;margin:0 0 .5em;letter-spacing:-.01em}
h1{font-size:clamp(2rem,4.6vw,3.4rem);font-weight:800}
h2{font-size:clamp(1.55rem,3vw,2.3rem);font-weight:800}
h3{font-size:1.1rem;font-weight:700}
p{margin:0 0 1em}
em{font-style:normal;color:var(--p)}
.eyebrow{font-size:.78rem;font-weight:700;letter-spacing:.12em;text-transform:uppercase;color:var(--p);margin-bottom:.8em}

/* nút */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:.5em;padding:.7em 1.3em;border-radius:999px;background:var(--p);color:#fff;
  font:600 .95rem var(--font);text-decoration:none;border:2px solid var(--p);cursor:pointer;transition:transform .15s,background .15s,box-shadow .15s}
.btn:hover{background:var(--pd);border-color:var(--pd);transform:translateY(-1px);box-shadow:var(--sh)}
.btn:focus-visible,a:focus-visible,button:focus-visible,summary:focus-visible,input:focus-visible{outline:3px solid var(--a);outline-offset:2px}
.btn-lg{padding:.9em 1.7em;font-size:1rem}
.btn-sm{padding:.5em 1.1em;font-size:.88rem}
.btn-ghost{background:transparent;color:var(--p);border-color:var(--p)}
.btn-ghost:hover{background:var(--soft);color:var(--pd)}
.btn-light{background:#fff;color:var(--dark);border-color:#fff}
.btn-light:hover{background:var(--soft);color:var(--dark);border-color:var(--soft)}

/* header */
.top{position:sticky;top:0;z-index:20;background:color-mix(in srgb,var(--bg) 88%,transparent);backdrop-filter:blur(10px);border-bottom:1px solid var(--line)}
.top-in{display:flex;align-items:center;gap:20px;height:64px}
.logo{display:flex;align-items:center;gap:10px;text-decoration:none;font-weight:700}
.logo-mark{display:grid;place-items:center;width:32px;height:32px;border-radius:9px;background:var(--p);color:#fff;font-weight:800}
.logo-text b,.foot .logo-text b{color:var(--p)}
.nav{display:flex;gap:24px;margin-left:auto}
.nav a{text-decoration:none;font-size:.92rem;font-weight:500;color:var(--muted)}
.nav a:hover{color:var(--ink)}
.burger{display:none;background:none;border:0;padding:8px;cursor:pointer}
.burger span{display:block;width:22px;height:2px;background:var(--ink);margin:5px 0;transition:.2s}

/* hero */
.hero{padding:64px 0 56px;background:
  radial-gradient(900px 400px at 85% -10%,var(--soft),transparent 60%),var(--bg)}
.hero-in{display:grid;grid-template-columns:1.1fr .9fr;gap:48px;align-items:center}
.lead{font-size:1.1rem;color:var(--muted);max-width:56ch}
.ask{margin:26px 0 4px;max-width:600px}
.ask-label{font-size:.9rem;font-weight:600;color:var(--ink);margin:0 0 10px}
.linkbtn{background:none;border:0;padding:0 0 10px;color:var(--p);font:600 .85rem var(--font);cursor:pointer;text-decoration:underline}
.linkbtn[hidden]{display:none}
.cta{display:flex;flex-wrap:wrap;gap:12px;margin:20px 0 20px}
.trust{display:flex;flex-wrap:wrap;gap:8px 22px;list-style:none;padding:0;margin:0;font-size:.88rem;color:var(--muted)}
.trust li::before{content:"✓";color:var(--p);font-weight:800;margin-right:6px}

.hero-demo{display:flex;justify-content:center}
.phone{width:min(380px,100%);background:var(--card);border:1px solid var(--line);border-radius:24px;box-shadow:var(--sh);overflow:hidden}
.phone-bar{display:flex;align-items:center;gap:8px;padding:14px 16px;background:var(--dark);color:var(--on-dark)}
.phone-bar small{margin-left:auto;font-size:.72rem;opacity:.75}
.dot{width:9px;height:9px;border-radius:50%;background:#35c46b}
.msgs{padding:16px;display:flex;flex-direction:column;gap:10px;font-size:.92rem}
.m{max-width:86%;padding:10px 14px;border-radius:16px;line-height:1.5}
.m.me{align-self:flex-end;background:var(--p);color:#fff;border-bottom-right-radius:4px}
.m.bot{align-self:flex-start;background:var(--alt);border-bottom-left-radius:4px}
.m.soft{border:1px dashed var(--a)}
.cite{display:inline-grid;place-items:center;min-width:18px;height:18px;padding:0 4px;border-radius:9px;background:var(--a);color:#241a05;font-size:.68rem;font-weight:700;vertical-align:1px}
.chips{display:flex;flex-wrap:wrap;gap:6px;margin-top:10px}
.chips span{padding:4px 10px;border:1px solid var(--p);color:var(--p);border-radius:999px;font-size:.78rem;font-weight:600}
.source{padding:10px 16px;border-top:1px solid var(--line);font-size:.78rem;color:var(--muted)}

.strip{border-block:1px solid var(--line);background:var(--alt)}
.strip-in{display:flex;flex-wrap:wrap;align-items:center;gap:10px 34px;padding:16px 0;font-size:.9rem;color:var(--muted)}
.strip-in b{color:var(--ink);font-weight:600}
.strip-in em{font-size:.7rem;border:1px solid var(--line);border-radius:999px;padding:1px 8px;margin-left:4px;color:var(--muted)}

/* section */
.sec{padding:84px 0}
.sec-alt{background:var(--alt)}
.sec-head{max-width:720px;margin:0 auto 44px;text-align:center}
.sec-head.left{text-align:left;margin:0 0 30px}
.sec-head p{color:var(--muted)}
.grid3{display:grid;grid-template-columns:repeat(3,1fr);gap:20px}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:28px}
.ico{display:grid;place-items:center;width:44px;height:44px;border-radius:12px;background:var(--soft);color:var(--p);font-size:1.3rem;font-weight:800;margin-bottom:16px}
.card p{color:var(--muted);margin:0}

.steps{list-style:none;padding:0;margin:0;display:grid;grid-template-columns:repeat(3,1fr);gap:20px;counter-reset:s}
.steps li{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:28px}
.steps .n{display:grid;place-items:center;width:36px;height:36px;border-radius:50%;background:var(--p);color:#fff;font-weight:800;margin-bottom:14px}
.steps p{color:var(--muted);margin:0}

/* dùng thử */
.try{background:var(--dark);color:var(--on-dark)}
.try .eyebrow{color:var(--a)}
.try-in{display:grid;grid-template-columns:1fr 1fr;gap:48px;align-items:center}
.try-copy p{color:#b8c4d6}
.ticks{list-style:none;padding:0;margin:20px 0 0;display:grid;gap:10px}
.ticks li::before{content:"✓";color:var(--p);font-weight:800;margin-right:10px}
.try .ticks li::before{color:var(--a)}
.form{background:var(--card);color:var(--ink);border-radius:20px;padding:28px;display:grid;gap:16px;box-shadow:0 20px 50px rgba(0,0,0,.3)}
.form label{display:grid;gap:6px;font-size:.88rem;font-weight:600}
.form input[type=url],.form input[type=text],.form input[type=tel]{width:100%;padding:12px 14px;border:1.5px solid var(--line);border-radius:10px;font:1rem var(--font);background:var(--bg);color:var(--ink)}
.form input:focus{border-color:var(--p)}
.form .check{display:flex;gap:10px;align-items:flex-start;font-weight:400;color:var(--muted)}
.form .check input{margin-top:5px;accent-color:var(--p)}
.form-msg{min-height:1.4em;margin:0;font-size:.9rem;color:var(--muted)}
.form-msg.err{color:#c0392b}
.form-msg.ok{color:var(--p);font-weight:600}
.form button[disabled]{opacity:.6;cursor:progress}

/* so sánh */
.split{display:grid;grid-template-columns:1fr 1.1fr;gap:48px;align-items:center}
.cmp{overflow-x:auto;background:var(--card);border:1px solid var(--line);border-radius:var(--r)}
.cmp table{width:100%;border-collapse:collapse;font-size:.9rem;min-width:420px}
.cmp th,.cmp td{padding:13px 16px;text-align:left;border-bottom:1px solid var(--line)}
.cmp tr:last-child td{border-bottom:0}
.cmp th{font-size:.78rem;text-transform:uppercase;letter-spacing:.06em;color:var(--muted)}
.cmp .us{background:var(--soft);font-weight:600;color:var(--pd)}
.cmp td:first-child{font-weight:600}

/* giá */
.demo-note{font-size:.85rem;color:var(--a);font-weight:600}
.toggle{display:inline-flex;padding:4px;background:var(--alt);border:1px solid var(--line);border-radius:999px;margin-top:10px}
.toggle button{border:0;background:transparent;padding:8px 18px;border-radius:999px;font:600 .88rem var(--font);color:var(--muted);cursor:pointer}
.toggle button.on{background:var(--p);color:#fff}
.toggle i{font-style:normal;font-size:.7rem;margin-left:6px;opacity:.85}
.plans{display:grid;grid-template-columns:repeat(3,1fr);gap:20px;align-items:stretch}
.plan{position:relative;display:flex;flex-direction:column;background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:30px}
.plan.hot{border:2px solid var(--p);box-shadow:var(--sh)}
.badge{position:absolute;top:-13px;left:30px;background:var(--a);color:#241a05;font-size:.75rem;font-weight:700;padding:3px 12px;border-radius:999px}
.who{color:var(--muted);font-size:.9rem;min-height:2.8em}
.price{margin:10px 0 20px}
.price b{font-size:2.1rem;font-weight:800}
.price small{color:var(--muted);margin-left:4px}
.plan ul{list-style:none;padding:0;margin:0 0 26px;display:grid;gap:10px;flex:1;font-size:.93rem}
.plan li::before{content:"✓";color:var(--p);font-weight:800;margin-right:9px}
.plan li.no{color:var(--muted);text-decoration:line-through}
.plan li.no::before{content:"–";color:var(--muted)}

/* hỏi đáp */
.faq-wrap{max-width:820px}
.faq details{background:var(--card);border:1px solid var(--line);border-radius:12px;margin-bottom:10px;padding:0 20px}
.faq summary{cursor:pointer;padding:18px 0;font-weight:600;list-style:none;display:flex;justify-content:space-between;gap:16px}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"+";font-size:1.4rem;line-height:1;color:var(--p)}
.faq details[open] summary::after{content:"–"}
.faq details p{color:var(--muted);padding-bottom:18px;margin:0}

.final{background:linear-gradient(135deg,var(--pd),var(--p));color:#fff;text-align:center;padding:72px 0}
.final h2{color:#fff}
.final p{opacity:.9;margin-bottom:24px}

.foot{padding:28px 0;border-top:1px solid var(--line);font-size:.85rem;color:var(--muted)}
.foot-in{display:flex;flex-wrap:wrap;justify-content:space-between;gap:10px}
.foot-links{display:flex;flex-wrap:wrap;gap:6px 18px}
.foot-links a,.foot-co a{text-decoration:none;color:inherit}
.foot-links a:hover,.foot-co a:hover{color:var(--p);text-decoration:underline}
.foot-co{flex-basis:100%}

/* trang văn bản pháp lý */
.legal{padding:48px 0 64px}
.legal-in{max-width:780px}
.legal h1{font-size:clamp(1.7rem,3.6vw,2.4rem)}
.legal h2{font-size:1.2rem;margin-top:1.8em}
.legal-date{color:var(--muted);font-size:.88rem}
.legal ul,.legal ol{padding-left:1.3em;margin:0 0 1em}
.legal li{margin-bottom:.4em}
.legal a{color:var(--p)}

/* điện thoại */
@media (max-width:900px){
  .hero-in,.try-in,.split{grid-template-columns:1fr;gap:32px}
  .grid3,.steps,.plans{grid-template-columns:1fr}
  .sec{padding:60px 0}
  .hero{padding:40px 0}
  .burger{display:block;margin-left:auto}
  .btn-sm{display:none}
  .nav{position:absolute;top:64px;left:0;right:0;flex-direction:column;gap:0;background:var(--bg);border-bottom:1px solid var(--line);display:none;margin:0}
  .nav.open{display:flex}
  .nav a{padding:14px 16px;border-top:1px solid var(--line)}
}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}*{transition:none!important}}

/* trang hỏi thử Trợ lý AI của khách (trial.html) */
.trial-page{padding:48px 0 64px;min-height:70vh}
.trial-in{max-width:760px}
.trial-in h1{font-size:clamp(1.6rem,3.6vw,2.4rem);overflow-wrap:anywhere}
.trial-note{margin:18px 0 0;padding:12px 16px;border:1px dashed var(--a);border-radius:12px;font-size:.88rem;color:var(--muted)}
.trial-note[hidden]{display:none}