/* Bố cục: trang sản phẩm kiểu hãng công nghệ – thanh điều hướng dính, hero nền sẫm có đường đồng mức cao nguyên + ảnh giao diện thật trong khung máy, các dải ngang xen kẽ trên lưới 1200px */
:root{
  --bg:#ffffff; --bg-2:#f2f5f9; --ink:#0b1726; --ink-2:#465569; --line:#dce3ec;
  --brand:#1f47d6; --brand-ink:#ffffff; --brand-soft:#e8eeff; --signal:#e2a03f;
  --deep:#071327; --deep-2:#0d1f3d; --on-deep:#eef3fb; --on-deep-2:#a9b8d0;
  --ok:#18794e; --frame:#ffffff; --shadow:0 24px 60px -24px rgba(11,23,38,.35);
  --f-sans:"Be Vietnam Pro","Segoe UI",Roboto,Arial,sans-serif;
  --f-mono:"JetBrains Mono",ui-monospace,Consolas,monospace;
  --wrap:1200px; --r:10px;
}
@media (prefers-color-scheme: dark){:root:not([data-theme="light"]){
  --bg:#0a111c; --bg-2:#0f1926; --ink:#e7edf5; --ink-2:#9dabbd; --line:#223146;
  --brand:#7491ff; --brand-ink:#08142b; --brand-soft:#16234a; --signal:#f0b65c;
  --deep:#050b16; --deep-2:#0b1830; --on-deep:#eef3fb; --on-deep-2:#a9b8d0;
  --ok:#5fd09a; --frame:#162236; --shadow:0 24px 60px -24px rgba(0,0,0,.7); color-scheme:dark}}
:root[data-theme="dark"]{
  --bg:#0a111c; --bg-2:#0f1926; --ink:#e7edf5; --ink-2:#9dabbd; --line:#223146;
  --brand:#7491ff; --brand-ink:#08142b; --brand-soft:#16234a; --signal:#f0b65c;
  --deep:#050b16; --deep-2:#0b1830; --on-deep:#eef3fb; --on-deep-2:#a9b8d0;
  --ok:#5fd09a; --frame:#162236; --shadow:0 24px 60px -24px rgba(0,0,0,.7); color-scheme:dark}

*{box-sizing:border-box}
html{scroll-behavior:smooth}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}}
body{margin:0;background:var(--bg);color:var(--ink);font:400 17px/1.65 var(--f-sans);-webkit-font-smoothing:antialiased}
body::before{content:"";position:fixed;inset:0 0 auto;height:env(safe-area-inset-top,0px);z-index:60;background:var(--deep)}
img{max-width:100%;height:auto;display:block}
a{color:var(--brand);text-underline-offset:3px}
h1,h2,h3,h4{margin:0;line-height:1.18;letter-spacing:-.02em;text-wrap:balance;font-weight:700}
h1{font-size:clamp(38px,5.6vw,66px);font-weight:800;letter-spacing:-.035em;line-height:1.06}
h2{font-size:clamp(30px,3.6vw,44px);font-weight:800;letter-spacing:-.03em}
h3{font-size:22px}
h4{font-size:18px}
p{margin:0;max-width:66ch}
.wrap{max-width:var(--wrap);margin:0 auto;padding-left:max(20px,env(safe-area-inset-left,0px));padding-right:max(20px,env(safe-area-inset-right,0px))}
.eyebrow{font:500 13px/1.4 var(--f-mono);letter-spacing:.12em;text-transform:uppercase;color:var(--brand)}
.lead{font-size:20px;color:var(--ink-2);line-height:1.6}
.muted{color:var(--ink-2)}
.small{font-size:14.5px}
:focus-visible{outline:3px solid var(--signal);outline-offset:3px;border-radius:4px}

/* nút */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:48px;padding:0 22px;border-radius:999px;font:600 16px var(--f-sans);text-decoration:none;border:1px solid transparent;cursor:pointer;transition:transform .15s,background .15s,border-color .15s;white-space:nowrap}
.btn:hover{transform:translateY(-1px)}
.btn-primary{background:var(--brand);color:var(--brand-ink)}
.btn-ghost{background:transparent;color:inherit;border-color:currentColor}
.btn-quiet{background:var(--bg-2);color:var(--ink);border-color:var(--line)}
.btn .ar{transition:transform .15s}
.btn:hover .ar{transform:translateX(3px)}
.link-ar{font-weight:600;text-decoration:none;display:inline-flex;gap:6px;align-items:center}
.link-ar:hover{text-decoration:underline}

/* dải thông báo + thanh điều hướng */
.notice{background:var(--deep);color:var(--on-deep-2);font-size:13.5px;text-align:center;padding-block:7px}
.notice b{color:var(--on-deep);font-weight:600}
.nav{position:sticky;top:env(safe-area-inset-top,0px);z-index:50;background:color-mix(in srgb,var(--bg) 88%,transparent);backdrop-filter:saturate(1.4) blur(14px);-webkit-backdrop-filter:saturate(1.4) blur(14px);border-bottom:1px solid var(--line)}
.nav .wrap{display:flex;align-items:center;gap:28px;min-height:68px}
.brand{display:flex;align-items:center;gap:11px;text-decoration:none;color:var(--ink);flex:none}
.brand svg{width:36px;height:36px;flex:none}
.brand b{font-weight:800;font-size:16.5px;letter-spacing:.02em;line-height:1.05}
.brand small{display:block;font:500 10.5px var(--f-mono);letter-spacing:.14em;color:var(--ink-2);margin-top:3px}
.menu{display:flex;align-items:center;gap:4px;margin:0;padding:0;list-style:none}
.menu>li{position:relative}
.menu a,.menu button.dd{display:inline-flex;align-items:center;gap:6px;min-height:44px;padding:0 12px;border-radius:8px;color:var(--ink);text-decoration:none;font:500 15.5px var(--f-sans);background:none;border:0;cursor:pointer}
.menu a:hover,.menu button.dd:hover,.menu a[aria-current="page"]{background:var(--bg-2)}
.menu a[aria-current="page"]{color:var(--brand)}
.dd svg{width:12px;height:12px;transition:transform .2s}
.dd[aria-expanded="true"] svg{transform:rotate(180deg)}
.mega{position:absolute;top:calc(100% + 10px);left:-12px;width:560px;background:var(--bg);border:1px solid var(--line);border-radius:14px;box-shadow:var(--shadow);padding:14px;display:grid;grid-template-columns:1.2fr 1fr;gap:10px}
.mega a{display:block;min-height:0;padding:14px;border-radius:10px;white-space:normal}
.mega a b{display:block;font-weight:700;margin-bottom:2px}
.mega a span{display:block;color:var(--ink-2);font-size:14px;line-height:1.45}
.mega .tag{display:inline-block;font:500 11px var(--f-mono);letter-spacing:.08em;text-transform:uppercase;color:var(--ink-2);border:1px solid var(--line);border-radius:999px;padding:1px 8px;margin-top:8px}
.mega .feature{background:var(--brand-soft)}
.nav-cta{margin-left:auto;display:flex;gap:10px;align-items:center}
.icon-btn{width:44px;height:44px;border-radius:999px;border:1px solid var(--line);background:var(--bg);color:var(--ink);display:grid;place-items:center;cursor:pointer}
.icon-btn svg{width:20px;height:20px}
.burger{display:none}
@media (max-width:1040px){
  .menu{display:none;position:fixed;inset:calc(68px + env(safe-area-inset-top,0px) + 34px) 0 0 0;flex-direction:column;align-items:stretch;background:var(--bg);padding:16px max(20px,env(safe-area-inset-right,0px)) calc(24px + env(safe-area-inset-bottom,0px)) max(20px,env(safe-area-inset-left,0px));overflow:auto;gap:2px}
  .nav.open .menu{display:flex}
  .menu a,.menu button.dd{font-size:19px;min-height:54px;width:100%;justify-content:space-between}
  .mega{position:static;width:auto;grid-template-columns:1fr;box-shadow:none;border:0;padding:0 0 8px 8px}
  .burger{display:grid}
  .nav-cta .btn{display:none}
}

/* hero sẫm */
.hero{position:relative;background:var(--deep);color:var(--on-deep);overflow:hidden;isolation:isolate}
.hero canvas.contour{position:absolute;inset:0;width:100%;height:100%;z-index:-1;opacity:.9}
.hero .wrap{padding-block:72px 0}
.hero .eyebrow{color:var(--signal)}
.hero h1{margin:18px 0 22px;max-width:16ch}
.hero .lead{color:var(--on-deep-2);max-width:58ch}
.hero .actions{display:flex;gap:12px;flex-wrap:wrap;margin-top:32px}
.hero .btn-primary{background:#fff;color:#071327}
.hero .btn-ghost{color:var(--on-deep);border-color:rgba(238,243,251,.35)}
.hero-sub{padding-block:64px 72px}
.hero-sub h1{font-size:clamp(34px,4.6vw,56px);max-width:20ch}

/* khung ảnh giao diện */
.stage{position:relative;margin-top:56px;padding-bottom:0}
.device{background:var(--frame);border-radius:14px 14px 0 0;border:1px solid rgba(255,255,255,.14);box-shadow:0 -10px 80px -20px rgba(31,71,214,.55);overflow:hidden}
.device .bar{display:flex;align-items:center;gap:7px;height:34px;padding:0 14px;background:#e9edf3;border-bottom:1px solid #d7dde6}
.device .bar i{width:10px;height:10px;border-radius:50%;background:#c6ccd6}
.device .bar span{margin-left:12px;font:500 12px var(--f-mono);color:#5b6779;background:#fff;border-radius:6px;padding:2px 12px}
.phone{position:absolute;right:3%;bottom:-40px;width:min(22%,230px);border-radius:30px;border:7px solid #0b1220;background:#0b1220;box-shadow:0 30px 60px -20px rgba(0,0,0,.6);overflow:hidden}
.phone img{border-radius:22px}
.shot{border-radius:12px;border:1px solid var(--line);box-shadow:var(--shadow);background:var(--frame);overflow:hidden}
.caption{font:500 12.5px var(--f-mono);color:var(--ink-2);margin-top:10px;letter-spacing:.02em}
@media (max-width:700px){.phone{display:none}.stage{margin-top:40px}.hero .wrap{padding-block:52px 0}}

/* dải nội dung */
section.band{padding-block:96px}
section.band.alt{background:var(--bg-2)}
section.band.dark{background:var(--deep);color:var(--on-deep)}
section.band.dark .muted,section.band.dark .lead{color:var(--on-deep-2)}
section.band.dark .eyebrow{color:var(--signal)}
.head{display:grid;gap:14px;margin-bottom:48px;max-width:760px}
.head.center{margin-inline:auto;text-align:center;justify-items:center}
@media (max-width:700px){section.band{padding-block:68px}}

.proof{border-bottom:1px solid var(--line);background:var(--bg)}
.proof .wrap{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:24px;padding-block:28px}
.proof div{display:flex;gap:12px;align-items:flex-start;font-size:15px;color:var(--ink-2)}
.proof b{display:block;color:var(--ink);font-size:15.5px}
.proof svg{width:26px;height:26px;flex:none;color:var(--brand);margin-top:2px}
@media (max-width:900px){.proof .wrap{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media (max-width:520px){.proof .wrap{grid-template-columns:1fr}}

/* tab quy trình */
.flow{display:grid;grid-template-columns:minmax(0,.9fr) minmax(0,1.6fr);gap:48px;align-items:start}
.flow-tabs{display:grid;gap:10px}
.flow-tab{text-align:left;padding:20px 22px;border-radius:14px;border:1px solid var(--line);background:var(--bg);cursor:pointer;font:inherit;color:inherit;display:grid;gap:6px;transition:border-color .2s,background .2s}
.flow-tab .step{font:500 12px var(--f-mono);letter-spacing:.1em;color:var(--ink-2);text-transform:uppercase}
.flow-tab b{font-size:19px}
.flow-tab p{color:var(--ink-2);font-size:15.5px}
.flow-tab[aria-selected="true"]{border-color:var(--brand);background:var(--brand-soft)}
.flow-tab[aria-selected="true"] .step{color:var(--brand)}
.flow-view{position:sticky;top:96px}
@media (max-width:900px){.flow{grid-template-columns:1fr}.flow-view{position:static}}

/* lưới tính năng */
.grid{display:grid;gap:22px}
.g3{grid-template-columns:repeat(3,minmax(0,1fr))}
.g2{grid-template-columns:repeat(2,minmax(0,1fr))}
.g4{grid-template-columns:repeat(4,minmax(0,1fr))}
@media (max-width:960px){.g3,.g4{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media (max-width:620px){.g3,.g2,.g4{grid-template-columns:1fr}}
.feat{display:grid;gap:10px;align-content:start;padding-top:22px;border-top:2px solid var(--ink)}
.feat svg{width:30px;height:30px;color:var(--brand)}
.feat p{color:var(--ink-2);font-size:16px}
.card{background:var(--bg);border:1px solid var(--line);border-radius:16px;padding:28px;display:grid;gap:12px;align-content:start}
.card.link{text-decoration:none;color:inherit;transition:border-color .2s,transform .2s}
.card.link:hover{border-color:var(--brand);transform:translateY(-2px)}
.card .meta{font:500 12px var(--f-mono);letter-spacing:.08em;text-transform:uppercase;color:var(--ink-2)}
.dark .card{background:var(--deep-2);border-color:rgba(255,255,255,.1)}

/* hàng xen ảnh/chữ */
.split{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1.25fr);gap:64px;align-items:center}
.split.rev>:first-child{order:2}
.split + .split{margin-top:104px}
.split .txt{display:grid;gap:16px}
.ticks{list-style:none;padding:0;margin:4px 0 0;display:grid;gap:10px}
.ticks li{display:flex;gap:10px;align-items:flex-start;color:var(--ink-2);font-size:16px}
.ticks li::before{content:"";flex:none;width:18px;height:18px;margin-top:4px;border-radius:50%;background:var(--brand-soft) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 20 20'%3E%3Cpath d='M5 10.5l3 3 7-7' fill='none' stroke='%231f47d6' stroke-width='2.4' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E") center/14px no-repeat}
@media (max-width:900px){.split{grid-template-columns:1fr;gap:28px}.split.rev>:first-child{order:0}.split + .split{margin-top:72px}}

/* bảng */
.tbl{overflow-x:auto;border:1px solid var(--line);border-radius:14px;background:var(--bg)}
table{border-collapse:collapse;width:100%;font-size:15.5px}
th,td{padding:14px 18px;text-align:left;border-bottom:1px solid var(--line);vertical-align:top}
th{font-weight:700;background:var(--bg-2);white-space:nowrap}
tr:last-child td{border-bottom:0}
td.n,th.n{text-align:right;font-variant-numeric:tabular-nums;white-space:nowrap}

/* bảng giá */
.plans{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:18px;align-items:stretch}
.plan{border:1px solid var(--line);border-radius:18px;padding:28px 24px;display:flex;flex-direction:column;gap:16px;background:var(--bg)}
.plan.pop{border:2px solid var(--brand);position:relative}
.plan.pop::before{content:"Phổ biến nhất";position:absolute;top:-13px;left:24px;background:var(--brand);color:var(--brand-ink);font:600 12px var(--f-mono);letter-spacing:.06em;padding:4px 10px;border-radius:999px}
.price{font-size:34px;font-weight:800;letter-spacing:-.03em;font-variant-numeric:tabular-nums;line-height:1.1}
.price small{font-size:15px;font-weight:500;color:var(--ink-2);letter-spacing:0}
.plan ul{list-style:none;padding:0;margin:0;display:grid;gap:9px;font-size:15px;color:var(--ink-2)}
.plan ul li b{color:var(--ink);font-variant-numeric:tabular-nums}
.plan .btn{margin-top:auto}
@media (max-width:1040px){.plans{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media (max-width:600px){.plans{grid-template-columns:1fr}}

/* hỏi đáp */
.faq{display:grid;gap:10px;max-width:860px}
.faq details{border:1px solid var(--line);border-radius:14px;background:var(--bg);padding:0 22px}
.faq summary{cursor:pointer;list-style:none;padding:20px 0;font-weight:600;font-size:17.5px;display:flex;justify-content:space-between;gap:16px}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"+";font-weight:400;font-size:24px;line-height:1;color:var(--brand)}
.faq details[open] summary::after{content:"–"}
.faq details p{padding-bottom:20px;color:var(--ink-2)}

/* lộ trình */
.road{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:0;border-top:2px solid var(--line);margin-top:8px}
.road div{padding:22px 22px 0 0;position:relative;display:grid;gap:8px;align-content:start}
.road div::before{content:"";position:absolute;top:-8px;left:0;width:14px;height:14px;border-radius:50%;background:var(--bg);border:3px solid var(--brand)}
.road .when{font:500 13px var(--f-mono);color:var(--brand);letter-spacing:.04em}
.road p{color:var(--ink-2);font-size:15.5px}
.dark .road{border-color:rgba(255,255,255,.18)}
.dark .road div::before{background:var(--deep)}
.dark .road .when{color:var(--signal)}
.dark .road div::before{border-color:var(--signal)}
@media (max-width:900px){.road{grid-template-columns:1fr 1fr;row-gap:28px}}
@media (max-width:520px){.road{grid-template-columns:1fr}}

/* CTA */
.cta{background:var(--brand);color:var(--brand-ink);border-radius:24px;padding:56px;display:grid;grid-template-columns:minmax(0,1.4fr) auto;gap:32px;align-items:center;position:relative;overflow:hidden}
.cta h2{max-width:20ch}
.cta p{opacity:.88;margin-top:12px}
.cta .btn-primary{background:var(--brand-ink);color:var(--brand)}
@media (max-width:800px){.cta{grid-template-columns:1fr;padding:36px 26px}}

/* biểu mẫu */
form.f{display:grid;gap:18px;background:var(--bg);border:1px solid var(--line);border-radius:18px;padding:32px}
.f .row{display:grid;grid-template-columns:1fr 1fr;gap:18px}
@media (max-width:620px){.f .row{grid-template-columns:1fr}form.f{padding:22px}}
.f label{display:grid;gap:7px;font-weight:600;font-size:15px}
.f input,.f select,.f textarea{font:400 16px var(--f-sans);color:var(--ink);background:var(--bg-2);border:1px solid var(--line);border-radius:10px;padding:12px 14px;min-height:50px;width:100%}
.f textarea{min-height:110px;resize:vertical}
.f .chk{display:flex;gap:10px;align-items:flex-start;font-weight:400;color:var(--ink-2);font-size:14.5px}
.f .chk input{width:20px;min-height:20px;height:20px;margin-top:2px;flex:none}
.f .err{color:#c0392b;font-size:14px;font-weight:500}
.msg{border-radius:12px;padding:16px 18px;background:var(--brand-soft);color:var(--ink)}
.copyline{display:flex;gap:10px;align-items:center;flex-wrap:wrap}
.copyline code{font:500 15px var(--f-mono);background:var(--bg-2);border:1px solid var(--line);border-radius:8px;padding:6px 10px;user-select:all;word-break:break-all}

/* văn bản pháp lý */
.legal{max-width:780px;display:grid;gap:18px}
.legal h2{font-size:26px;margin-top:22px}
.legal p,.legal li{color:var(--ink-2)}
.legal ul,.legal ol{margin:0;padding-left:22px;display:grid;gap:6px}
.draft{border:1px dashed var(--signal);border-radius:12px;padding:14px 18px;font-size:15px;color:var(--ink-2)}

/* chân trang */
footer.site{background:var(--deep);color:var(--on-deep-2);padding-block:72px calc(32px + env(safe-area-inset-bottom,0px));font-size:15px}
footer.site .cols{display:grid;grid-template-columns:1.6fr repeat(4,minmax(0,1fr));gap:32px}
footer.site h4{color:var(--on-deep);font-size:14px;font-family:var(--f-mono);font-weight:500;letter-spacing:.1em;text-transform:uppercase;margin-bottom:14px}
footer.site ul{list-style:none;margin:0;padding:0;display:grid;gap:9px}
footer.site a{color:var(--on-deep-2);text-decoration:none}
footer.site a:hover{color:var(--on-deep);text-decoration:underline}
footer.site .brand{color:var(--on-deep)}
footer.site .brand small{color:var(--on-deep-2)}
footer.site .base{border-top:1px solid rgba(255,255,255,.12);margin-top:48px;padding-top:24px;display:flex;justify-content:space-between;gap:16px;flex-wrap:wrap;font-size:13.5px}
@media (max-width:900px){footer.site .cols{grid-template-columns:1fr 1fr}footer.site .cols>:first-child{grid-column:1/-1}}
[hidden]{display:none!important}
.card>svg{width:28px;height:28px;color:var(--brand)}
.dark .card>svg{color:var(--signal)}
section.band.tight{padding-top:0}
.device .bar span{white-space:nowrap;overflow:hidden;text-overflow:ellipsis;min-width:0}
@media (max-width:1040px){
  .menu{position:absolute;inset:auto 0 auto 0;top:100%;height:calc(100dvh - 100px - env(safe-area-inset-top,0px));border-top:1px solid var(--line)}
  .nav.open{background:var(--bg)}
}
/* Sửa 09/11: chữ menu không xuống dòng; thu gọn thành nút menu dưới 1200px */
.menu a,.menu button.dd{white-space:nowrap}
.nav .wrap{gap:20px}
@media (max-width:1200px){
  .menu{display:none;position:absolute;inset:auto 0 auto 0;top:100%;height:calc(100dvh - 100px - env(safe-area-inset-top,0px));flex-direction:column;align-items:stretch;background:var(--bg);padding:16px max(20px,env(safe-area-inset-right,0px)) calc(24px + env(safe-area-inset-bottom,0px)) max(20px,env(safe-area-inset-left,0px));overflow:auto;gap:2px;border-top:1px solid var(--line)}
  .nav.open .menu{display:flex}
  .nav.open{background:var(--bg)}
  .menu a,.menu button.dd{font-size:19px;min-height:54px;width:100%;justify-content:space-between}
  .mega{position:static;width:auto;grid-template-columns:1fr;box-shadow:none;border:0;padding:0 0 8px 8px}
  .burger{display:grid}
}
@media (max-width:640px){.nav-cta .btn{display:none}}