/* site.css – giao diện chung: header, footer, module (hero, cards, steps, faq, cta...). Màu: trắng/xám, chữ đen, xanh đậm. Cỡ chữ 14px. */
:root{
  --navy:#0B2A5B; --navy-2:#143A7A; --blue-ink:#0B2A5B;
  --bg:#FFFFFF; --surface:#F3F4F6; --text:#111111; --muted:#4B5563; --line:#E1E4EA;
  --head:#111111; color-scheme:light;
  box-sizing:border-box; padding-top:env(safe-area-inset-top,0px); padding-bottom:env(safe-area-inset-bottom,0px);
}
:root[data-theme="dark"]{--bg:#0A1426;--surface:#101E38;--text:#E6EBF5;--muted:#9FAAC2;--line:#22345A;--head:#FFFFFF;--navy:#2F5FB3;--navy-2:#4A78C8;--blue-ink:#8DB2F2;color-scheme:dark}
html{scroll-padding-top:env(safe-area-inset-top,0px)}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--text);font:14px/1.65 "Be Vietnam Pro",system-ui,"Segoe UI",Arial,sans-serif}
a{color:inherit;text-decoration:none}
h1,h2,h3{color:var(--head);line-height:1.25;margin:0 0 .5em}
h1{font-size:34px;font-weight:800}h2{font-size:24px;font-weight:800}h3{font-size:16px;font-weight:700}
p{margin:0 0 1em}
:focus-visible{outline:3px solid var(--blue-ink);outline-offset:2px}
.wrap{max-width:1080px;margin:0 auto;padding:0 20px}

/* ===== MODULE: header ===== */
.hdr{position:sticky;top:env(safe-area-inset-top,0px);z-index:20;background:var(--bg);color:var(--text);border-bottom:1px solid var(--line)}
body::before{content:"";position:fixed;inset:0 0 auto;height:env(safe-area-inset-top,0px);background:var(--bg);z-index:30}
.hdr .wrap{display:flex;align-items:center;justify-content:space-between;height:60px}
.brand{font-weight:800;font-size:16px;display:flex;align-items:center;gap:8px}
.brand i{width:10px;height:10px;background:var(--navy);display:inline-block;border-radius:2px}
.nav{display:flex;gap:4px;align-items:center}
.nav a,.nav button{color:inherit;background:none;border:0;font:inherit;padding:8px 12px;border-radius:6px;cursor:pointer}
.nav a:hover,.nav button:hover,.nav a.on{background:var(--surface)}
.nav a.on{box-shadow:inset 0 -3px 0 var(--navy);border-radius:6px 6px 0 0}
.dd{position:relative}
.dd-menu{display:none;position:absolute;left:0;top:100%;min-width:320px;background:var(--bg);color:var(--text);border:1px solid var(--line);border-top:3px solid var(--navy);border-radius:0 0 8px 8px;padding:6px;box-shadow:0 12px 30px rgba(0,0,0,.25)}
.dd:hover .dd-menu,.dd.open .dd-menu,.dd:focus-within .dd-menu{display:block}
.dd-menu a{display:block;color:var(--text)}
.dd-menu a:hover{background:var(--surface)}
.burger{display:none}

/* ===== MODULE: hero ===== */
.hero{background:var(--surface);color:var(--text);padding:64px 0 72px;border-bottom:1px solid var(--line)}
.hero-in{display:grid;grid-template-columns:1fr 1fr;gap:32px;align-items:center}
.hero h1{max-width:760px}
.hero p{max-width:620px;font-size:16px;color:var(--muted)}
.art{color:var(--blue-ink);width:100%;max-width:340px;justify-self:center}
.video{width:100%}
.video .frame{position:relative;aspect-ratio:16/9;background:var(--bg);border:2px solid var(--navy);border-radius:8px;overflow:hidden}
.video iframe{position:absolute;inset:0;width:100%;height:100%;border:0}
.video .ph{position:absolute;inset:0;display:grid;place-content:center;justify-items:center;gap:8px;color:var(--blue-ink);text-align:center;padding:16px}
.video .ph svg{width:56px;height:56px}
.video .ph span{color:var(--muted)}
.video .alt-link{display:inline-block;margin-top:8px;font-weight:700;color:var(--blue-ink);border-bottom:2px solid var(--navy)}
.hero.sm{padding:48px 0 52px}
.hero.sm h1{font-size:28px}

/* ===== MODULE: button ===== */
.btn{display:inline-block;padding:11px 22px;border-radius:6px;font-weight:700;border:2px solid var(--navy);background:var(--navy);color:#fff;margin:4px 10px 4px 0}
.btn:hover{filter:brightness(1.12)}
.btn.ghost{background:transparent;color:var(--blue-ink);border-color:var(--navy)}

/* ===== MODULE: section / cards / steps / faq / cta ===== */
.sec{padding:56px 0}.sec.alt{background:var(--surface)}
.sec-head{max-width:640px;margin-bottom:28px}
.sec-head p{color:var(--muted)}
.cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:16px}
.card{display:block;background:var(--bg);border:1px solid var(--line);border-left:4px solid var(--navy);border-radius:6px;padding:20px}
.alt .card{background:var(--bg)}
a.card:hover{border-color:var(--navy-2);border-left-color:var(--navy);transform:translateY(-2px);transition:transform .15s}
.card p{color:var(--muted);margin:0}
.card .more{display:inline-block;margin-top:10px;font-weight:700;color:var(--blue-ink);border-bottom:2px solid var(--navy)}
.steps{counter-reset:s;display:grid;gap:14px;max-width:720px}
.step{display:flex;gap:16px;align-items:flex-start}
.step::before{counter-increment:s;content:counter(s);flex:none;width:34px;height:34px;border-radius:50%;background:var(--navy);color:#fff;font-weight:800;display:grid;place-items:center;box-shadow:0 0 0 3px var(--line)}
.step p{margin:0;color:var(--muted)}
.faq{max-width:760px}
.faq details{border-bottom:1px solid var(--line);padding:12px 0}
.faq summary{font-weight:700;cursor:pointer;color:var(--head)}
.faq p{margin:8px 0 0;color:var(--muted)}
.cta{background:var(--surface);color:var(--text);padding:48px 0;border-top:1px solid var(--line)}
.cta p{color:var(--muted)}
.split{display:grid;grid-template-columns:1fr 1fr;gap:32px;align-items:start}
.panel{background:var(--surface);border:1px solid var(--line);border-radius:6px;padding:24px}

/* ===== MODULE: footer (3 cột) ===== */
.ftr{background:var(--surface);color:var(--text);padding:44px 0 20px;border-top:1px solid var(--line)}
.ftr .cols{display:grid;grid-template-columns:1.3fr 1.2fr 1fr;gap:32px}
.ftr h3{color:var(--blue-ink);font-size:15px}
.ftr ul{list-style:none;margin:0;padding:0}.ftr li{margin-bottom:6px}
.ftr a:hover{color:var(--blue-ink);text-decoration:underline}
.ftr .copy{margin-top:28px;padding-top:14px;border-top:1px solid var(--line);font-size:13px;color:var(--muted)}

@media(max-width:820px){
  h1{font-size:27px}.hero{padding:48px 0 54px}
  .burger{display:block;background:none;border:2px solid var(--line);color:var(--text);border-radius:6px;padding:6px 10px;font:inherit}
  .nav{display:none;position:absolute;left:0;right:0;top:60px;background:var(--bg);border-bottom:1px solid var(--line);flex-direction:column;align-items:stretch;padding:8px 20px 16px}
  .nav.open{display:flex}
  .dd-menu{position:static;display:block;border:0;border-left:3px solid var(--navy);box-shadow:none;background:transparent;color:inherit;min-width:0;margin-left:12px;padding:0}
  .dd-menu a{color:var(--text)}.dd-menu a:hover{background:var(--surface)}
  .split,.ftr .cols,.hero-in{grid-template-columns:1fr}
  .art{max-width:240px;justify-self:start}
}
@media(prefers-reduced-motion:reduce){*{transition:none!important}}