:root{
  --brand:#36458f; --brand-deep:#1E40AF; --navy:#10142e; --navy2:#181e42;
  --ink:#1c2140; --muted:#525a75; --line:#e5e9f4;
  --bg:#f6f8fd; --card:#ffffff; --gold:#f5b301; --green:#059669;
  --shadow-lg:0 24px 60px rgba(16,20,46,.16);
  --shadow-md:0 10px 30px rgba(16,20,46,.10);
  --radius:20px;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{font-family:'Be Vietnam Pro',system-ui,-apple-system,'Segoe UI',Arial,sans-serif;color:var(--ink);background:var(--bg);line-height:1.65;-webkit-font-smoothing:antialiased}
/* height:auto 是必需的：img 标签带 width/height 属性是为了让浏览器据此算 aspect-ratio
   预留空间（压 CLS），但若 CSS 只约束 width 而不显式给 height，HTML 的 height 属性会被
   当成真实高度使用，导致 logo 与截图被纵向拉伸。需要正方形的地方由更具体的规则
   （如 .brand img{width:32px;height:32px}）覆盖。*/
img{max-width:100%;display:block;height:auto}
a{color:inherit;text-decoration:none;cursor:pointer}
ul{list-style:none}
.wrap{max-width:1160px;margin:0 auto;padding:0 24px}
section{padding:92px 0}
h2.sec{font-size:clamp(26px,3.4vw,38px);font-weight:800;letter-spacing:-.02em;line-height:1.25;margin:8px 0 14px}
.kicker{display:inline-flex;align-items:center;gap:8px;color:var(--brand-deep);background:#e9eeff;border:1px solid #d7e0fb;border-radius:999px;padding:5px 14px;font-weight:700;font-size:12.5px;letter-spacing:.08em;text-transform:uppercase}
.sub{color:var(--muted);max-width:660px;margin-bottom:48px;font-size:16.5px}
.icon{width:24px;height:24px;stroke:currentColor;stroke-width:2;fill:none;stroke-linecap:round;stroke-linejoin:round;flex:none}

/* reveal animation */
.reveal{opacity:0;transform:translateY(26px);transition:opacity .7s ease,transform .7s ease}
.reveal.on{opacity:1;transform:none}
@media(prefers-reduced-motion:reduce){.reveal{opacity:1;transform:none;transition:none}}

/* ---------- header ---------- */
header{position:fixed;top:14px;left:0;right:0;z-index:60}
.pill{max-width:1160px;margin:0 auto;background:rgba(16,20,46,.82);backdrop-filter:blur(14px);border:1px solid rgba(255,255,255,.10);border-radius:999px;display:flex;align-items:center;gap:22px;padding:9px 10px 9px 20px;box-shadow:0 12px 34px rgba(16,20,46,.35)}
.brand{display:flex;align-items:center;gap:10px;font-weight:800;font-size:18px;color:#fff}
.brand img{width:32px;height:32px;border-radius:8px}
.navlinks{display:flex;gap:20px;margin-left:auto;font-size:14px;font-weight:500;color:#c4cbe8}
.navlinks a:hover{color:#fff}
.btn{display:inline-flex;align-items:center;gap:8px;background:var(--gold);color:#231a00;font-weight:700;border-radius:999px;padding:10px 20px;font-size:14px;transition:transform .18s,box-shadow .18s;box-shadow:0 6px 18px rgba(245,179,1,.35)}
.btn:hover{transform:translateY(-2px);box-shadow:0 10px 24px rgba(245,179,1,.45)}
@media(max-width:900px){.navlinks{display:none}}

/* ---------- hero ---------- */
.hero{position:relative;background:radial-gradient(1100px 620px at 82% -10%,rgba(54,69,143,.55),transparent 60%),radial-gradient(800px 500px at 8% 108%,rgba(30,64,175,.35),transparent 60%),linear-gradient(165deg,var(--navy2) 0%,var(--navy) 100%);color:#fff;padding:170px 0 110px;overflow:hidden}
.hero::before{content:"";position:absolute;inset:0;background-image:linear-gradient(rgba(255,255,255,.045) 1px,transparent 1px),linear-gradient(90deg,rgba(255,255,255,.045) 1px,transparent 1px);background-size:44px 44px;mask-image:radial-gradient(ellipse at 50% 40%,#000 30%,transparent 75%);pointer-events:none}
.hero .wrap{position:relative;display:flex;align-items:center;gap:60px}
.hero h1{font-size:clamp(34px,4.6vw,54px);line-height:1.15;font-weight:900;letter-spacing:-.02em}
.hero h1 em{font-style:normal;background:linear-gradient(92deg,var(--gold),#ffe27a);-webkit-background-clip:text;background-clip:text;color:transparent}
.hero p.lead{margin:20px 0 32px;font-size:17.5px;color:#d8ddf3;max-width:560px}
.play-badge{display:inline-flex;align-items:center;gap:13px;background:#000;border:1px solid rgba(255,255,255,.4);border-radius:16px;padding:11px 24px 11px 17px;transition:transform .18s,box-shadow .18s;box-shadow:0 10px 28px rgba(0,0,0,.4)}
.play-badge:hover{transform:translateY(-2px)}
.play-badge svg{width:26px;height:26px;flex:none}
.play-badge small{display:block;font-size:10.5px;color:#c9cde4;text-align:left;letter-spacing:.04em}
.play-badge b{display:block;font-size:17.5px;font-weight:700;color:#fff;text-align:left;line-height:1.2}
.hero-cta{display:flex;align-items:center;gap:18px;flex-wrap:wrap}
.hero-note{font-size:13px;color:#aeb6da;display:flex;align-items:center;gap:7px}
.hero-note svg{width:16px;height:16px;stroke:var(--green)}
.chips{display:flex;flex-wrap:wrap;gap:10px;margin-top:30px}
.chip{display:inline-flex;align-items:center;gap:7px;border:1px solid rgba(255,255,255,.28);background:rgba(255,255,255,.06);border-radius:999px;padding:7px 15px;font-size:13px;color:#e8ebfa;backdrop-filter:blur(4px)}
.chip svg{width:15px;height:15px;stroke:var(--gold)}
.hero-visual{flex:0 0 auto;position:relative}
.hero-visual img.phone{width:282px;border-radius:36px;border:8px solid #0b0f24;box-shadow:var(--shadow-lg);position:relative;z-index:2}
.hero-visual::after{content:"";position:absolute;width:340px;height:340px;left:-30px;top:50%;transform:translateY(-50%);background:radial-gradient(closest-side,rgba(245,179,1,.20),transparent);z-index:1}
.float-card{position:absolute;z-index:3;background:rgba(255,255,255,.96);color:var(--ink);border-radius:14px;padding:11px 15px;box-shadow:var(--shadow-md);display:flex;align-items:center;gap:10px;font-size:12.5px;font-weight:600;animation:bob 5s ease-in-out infinite}
.float-card svg{width:20px;height:20px;stroke-width:2.2}
.float-card small{display:block;font-weight:500;color:var(--muted);font-size:11px}
.fc1{top:11%;left:-108px}
.fc2{bottom:15%;right:-96px;animation-delay:2.2s}
@keyframes bob{0%,100%{transform:translateY(0)}50%{transform:translateY(-9px)}}
@media(prefers-reduced-motion:reduce){.float-card{animation:none}}
@media(max-width:960px){.hero .wrap{flex-direction:column;text-align:center}.chips{justify-content:center}.hero-cta{justify-content:center}.hero-visual img.phone{width:250px}.fc1{left:-40px}.fc2{right:-40px}}

/* ---------- trust strip ---------- */
.truststrip{background:var(--navy);color:#9aa3c8;border-bottom:1px solid rgba(255,255,255,.07);padding:16px 0}
.truststrip .wrap{display:flex;flex-wrap:wrap;gap:14px 34px;justify-content:center;font-size:13px}
.truststrip span{display:inline-flex;align-items:center;gap:8px}
.truststrip svg{width:15px;height:15px;stroke:var(--gold)}

/* ---------- stats ---------- */
#stats{padding:64px 0;background:#fff;border-bottom:1px solid var(--line)}
.stats{display:grid;grid-template-columns:repeat(4,1fr);gap:20px;text-align:center}
.stat b{font-size:clamp(30px,4vw,44px);font-weight:900;color:var(--brand-deep);letter-spacing:-.02em;display:block}
.stat span{font-size:14px;color:var(--muted);font-weight:500}
@media(max-width:700px){.stats{grid-template-columns:1fr 1fr;gap:30px}}

/* ---------- features ---------- */
.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:22px}
@media(max-width:960px){.grid{grid-template-columns:1fr 1fr}}
@media(max-width:620px){.grid{grid-template-columns:1fr}}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:28px;box-shadow:0 3px 14px rgba(16,20,46,.045);transition:transform .22s ease,box-shadow .22s ease,border-color .22s}
.card:hover{transform:translateY(-5px);box-shadow:var(--shadow-md);border-color:#cdd8f5}
.card .ic{width:52px;height:52px;border-radius:15px;background:linear-gradient(145deg,#e9eeff,#dbe5ff);color:var(--brand-deep);display:flex;align-items:center;justify-content:center;margin-bottom:18px}
.card h3{font-size:18px;font-weight:700;margin-bottom:8px;letter-spacing:-.01em}
.card p{font-size:14.5px;color:var(--muted)}

/* ---------- screenshots ---------- */
#screens{background:linear-gradient(180deg,#fff 0%,var(--bg) 100%)}
.shots{display:flex;gap:24px;overflow-x:auto;padding:10px 6px 26px;scroll-snap-type:x mandatory;scrollbar-width:thin}
.shot{flex:0 0 auto;scroll-snap-align:start;text-align:center}
.frame{width:224px;border-radius:30px;border:7px solid var(--navy);overflow:hidden;box-shadow:var(--shadow-md);background:var(--navy);transition:transform .22s}
.shot:hover .frame{transform:translateY(-6px)}
.frame img{width:100%}
.shot span{display:block;margin-top:14px;font-size:13.5px;font-weight:600;color:var(--ink);max-width:224px;margin-inline:auto}
.swipe-hint{color:var(--brand-deep);font-weight:600;font-size:14px}

/* ---------- trust/security ---------- */
#trust{background:linear-gradient(160deg,var(--navy2),var(--brand) 130%);color:#fff;border-radius:0}
#trust .kicker{background:rgba(255,255,255,.10);border-color:rgba(255,255,255,.25);color:#ffe9a8}
#trust .sub{color:#c6cde9}
.tgrid{display:grid;grid-template-columns:repeat(4,1fr);gap:20px}
@media(max-width:960px){.tgrid{grid-template-columns:1fr 1fr}}
@media(max-width:560px){.tgrid{grid-template-columns:1fr}}
.tcard{background:rgba(255,255,255,.07);border:1px solid rgba(255,255,255,.16);border-radius:18px;padding:24px;backdrop-filter:blur(6px);transition:background .22s,border-color .22s}
.tcard:hover{background:rgba(255,255,255,.12);border-color:rgba(255,255,255,.3)}
.tcard .ic{width:46px;height:46px;border-radius:13px;background:rgba(245,179,1,.16);color:var(--gold);display:flex;align-items:center;justify-content:center;margin-bottom:15px}
.tcard h3{font-size:16px;font-weight:700;margin-bottom:7px}
.tcard p{font-size:13.5px;color:#c3cae6}

/* ---------- audience ---------- */
.aud{display:grid;grid-template-columns:repeat(4,1fr);gap:18px}
@media(max-width:960px){.aud{grid-template-columns:1fr 1fr}}
@media(max-width:620px){.aud{grid-template-columns:1fr}}
.aud .card{display:flex;gap:14px;align-items:flex-start;padding:24px}
.aud .ic{width:44px;height:44px;border-radius:12px;background:linear-gradient(145deg,#e9eeff,#dbe5ff);color:var(--brand-deep);display:flex;align-items:center;justify-content:center;margin:0}
.aud b{display:block;font-size:15.5px;margin-bottom:3px}
.aud p{font-size:13.5px;color:var(--muted)}

/* ---------- faq ---------- */
#faq .wrap{max-width:840px}
details{background:#fff;border:1px solid var(--line);border-radius:16px;padding:20px 24px;margin-bottom:12px;transition:border-color .2s,box-shadow .2s}
details:hover{border-color:#cdd8f5;box-shadow:0 4px 16px rgba(16,20,46,.06)}
summary{cursor:pointer;font-weight:700;font-size:16px;list-style:none;position:relative;padding-right:30px}
summary::-webkit-details-marker{display:none}
summary::after{content:"";position:absolute;right:4px;top:7px;width:10px;height:10px;border-right:2.4px solid var(--brand-deep);border-bottom:2.4px solid var(--brand-deep);transform:rotate(45deg);transition:transform .2s}
details[open] summary::after{transform:rotate(-135deg)}
details p{margin-top:12px;color:var(--muted);font-size:15px}
details a{color:var(--brand-deep);font-weight:600}

/* ---------- cta banner ---------- */
.cta{position:relative;background:linear-gradient(140deg,var(--navy),var(--brand));border-radius:30px;color:#fff;padding:58px 52px;display:flex;align-items:center;gap:30px;flex-wrap:wrap;overflow:hidden;box-shadow:var(--shadow-lg)}
.cta::before{content:"";position:absolute;width:420px;height:420px;right:-120px;top:-160px;background:radial-gradient(closest-side,rgba(245,179,1,.25),transparent)}
.cta img{width:84px;border-radius:22px;position:relative}
.cta h2{font-size:clamp(22px,3vw,30px);font-weight:800;position:relative}
.cta p{color:#d8ddf3;margin-top:6px;position:relative}
.cta .go{margin-left:auto;position:relative}
@media(max-width:760px){.cta{padding:40px 26px}.cta .go{margin-left:0}}

/* ---------- footer ---------- */
footer{background:var(--navy);color:#a7aecf;font-size:14px;padding:64px 0 34px}
.fgrid{display:grid;grid-template-columns:2fr 1fr 1fr 1.3fr;gap:34px;margin-bottom:40px}
@media(max-width:800px){.fgrid{grid-template-columns:1fr}}
footer h4{color:#fff;font-size:15px;margin-bottom:15px}
footer a:hover{color:#fff}
footer li{margin-bottom:10px}
.fbrand{display:flex;align-items:center;gap:11px;font-weight:800;font-size:20px;color:#fff;margin-bottom:13px}
.fbrand img{width:36px;border-radius:9px}
.copy{border-top:1px solid rgba(255,255,255,.11);padding-top:24px;font-size:12.5px;color:#767ea8;line-height:1.9}

/* ---------- topic pages (article layout) ---------- */
.phero{background:radial-gradient(900px 480px at 88% -18%,rgba(54,69,143,.55),transparent 62%),linear-gradient(165deg,var(--navy2) 0%,var(--navy) 100%);color:#fff;padding:132px 0 52px}
.phero .crumbs{font-size:13px;color:#9aa3c8;margin-bottom:14px}
.phero .crumbs a{color:#c4cbe8;font-weight:600}
.phero .crumbs a:hover{color:#fff}
.phero h1{font-size:clamp(27px,4vw,42px);line-height:1.2;font-weight:900;letter-spacing:-.02em;max-width:820px}
.phero p.deck{margin:16px 0 0;font-size:17.5px;color:#d8ddf3;max-width:760px}
#article{padding:64px 0 30px}
.art{max-width:820px;margin:0 auto}
.art h2{font-size:clamp(20px,2.6vw,26px);font-weight:800;letter-spacing:-.01em;margin:34px 0 12px}
.art h3{font-size:17.5px;font-weight:700;margin:22px 0 8px}
.art p{font-size:16.5px;color:#3b4266;margin:0 0 14px;line-height:1.75}
.art .lede{font-size:18px;color:var(--ink);font-weight:500;margin-bottom:22px}
.art ul.bul{margin:0 0 18px}
.art ul.bul li{position:relative;padding-left:24px;margin-bottom:10px;font-size:16px;color:#3b4266;line-height:1.7}
.art ul.bul li::before{content:"";position:absolute;left:2px;top:10px;width:9px;height:9px;border-radius:3px;background:var(--gold)}
.art ul.bul li b{color:var(--ink)}
.art a{color:var(--brand-deep);font-weight:600;text-decoration:underline;text-underline-offset:2px}
.artbox{background:#fff;border:1px solid var(--line);border-left:4px solid var(--brand-deep);border-radius:16px;padding:22px 26px;margin:24px 0}
.artbox p{margin:0;font-size:15.5px;color:var(--muted)}
.artbox b{color:var(--ink)}
.related{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin-top:14px}
@media(max-width:620px){.related{grid-template-columns:1fr}}
.related a{display:block;background:#fff;border:1px solid var(--line);border-radius:16px;padding:20px 22px;transition:transform .2s,border-color .2s}
.related a:hover{transform:translateY(-4px);border-color:#cdd8f5}
.related b{display:block;font-size:15.5px;color:var(--ink);margin-bottom:4px}
.related span{font-size:13.5px;color:var(--muted)}

/* ---------- devlog: bảng số liệu & khối mã ---------- */
/* hai lớp selector (.art table) để thắng `ul{list-style:none}`/reset và đứng trên .art p */
.art table{width:100%;border-collapse:collapse;margin:22px 0;font-size:15px;background:#fff}
.art caption{caption-side:bottom;text-align:left;font-size:13px;color:var(--muted);padding-top:10px}
.art th,.art td{border:1px solid var(--line);padding:11px 14px;text-align:left;vertical-align:top}
.art th{background:#eef2fc;color:var(--ink);font-weight:700}
.art td{color:#3b4266}
.art tr:nth-child(even) td{background:#fafbff}
.art table b{color:var(--ink)}
.art pre{background:var(--navy);color:#dfe3f5;border-radius:14px;padding:18px 20px;overflow-x:auto;margin:20px 0;font-size:13.5px;line-height:1.7}
.art pre code{background:none;color:inherit;padding:0;font-size:inherit}
.art code{background:#e9eeff;color:var(--brand-deep);border-radius:6px;padding:2px 6px;font-size:.92em;
  font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace}
@media(max-width:620px){.art table{font-size:13.5px}.art th,.art td{padding:8px 10px}}