/* KhảoSát.statvn - one stylesheet, mobile first. Colors follow the VietSCI / ResearchSTAT brand. */
:root {
  --navy: #1A00AA; --navy-2: #3B1FD6; --ink: #0F172A; --text: #1E293B; --muted: #64748B; --line: #E2E8F0; --soft: #F6F5FD; --tint: #EEF0FF;
  --orange: #F97316; --green: #059669; --red: #DC2626; --amber: #B45309; --blue: #2563EB; --teal: #0E7490;
  --radius: 14px; --shadow: 0 1px 2px rgba(15,23,42,.06), 0 6px 24px rgba(26,0,170,.06); --shadow-lg: 0 20px 50px rgba(26,0,170,.14);
  --max: 1180px; --gutter: 16px;
  --font: "Be Vietnam Pro", system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif;
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body { margin: 0; font: 16px/1.65 var(--font); color: var(--text); background: #fff; overflow-wrap: break-word; }
img, svg { max-width: 100%; height: auto; }
a { color: var(--navy); text-underline-offset: 3px; }
h1, h2, h3, h4 { color: var(--ink); line-height: 1.25; letter-spacing: -.01em; margin: 0 0 .6em; }
h1 { font-size: clamp(1.75rem, 4.2vw, 2.9rem); }
h2 { font-size: clamp(1.4rem, 3vw, 2rem); }
h3 { font-size: 1.15rem; }
p { margin: 0 0 1em; }
.wrap { max-width: var(--max); margin: 0 auto; padding: 0 var(--gutter); }
.muted { color: var(--muted); }
.small { font-size: .88rem; }
.center { text-align: center; }
.sr { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); }
.skip { position: absolute; left: -999px; top: 8px; background: #fff; padding: 8px 12px; border-radius: 8px; z-index: 50; }
.skip:focus { left: 8px; }
:focus-visible { outline: 3px solid #A5B4FC; outline-offset: 2px; }

/* header */
.top { position: sticky; top: 0; z-index: 30; background: rgba(255,255,255,.92); backdrop-filter: saturate(1.4) blur(10px); border-bottom: 1px solid var(--line); }
.top .wrap { display: flex; align-items: center; gap: 16px; min-height: 66px; }
.brand { display: inline-flex; align-items: center; gap: 10px; text-decoration: none; color: var(--ink); }
.brand img { width: 40px; height: 40px; }
.brand b { display: block; font-size: 1.15rem; letter-spacing: -.02em; line-height: 1.1; }
.brand b span { color: var(--navy); }
.brand small { display: block; font-size: .68rem; color: var(--muted); letter-spacing: .02em; white-space: nowrap; }
.nav { display: flex; align-items: center; gap: 4px; margin-left: auto; }
.nav a { padding: 8px 11px; border-radius: 10px; text-decoration: none; color: var(--text); font-weight: 500; font-size: .94rem; white-space: nowrap; }
.nav a.btn-primary, .nav a.btn-primary:hover { color: #fff; background: var(--navy); }
.nav a:hover, .nav a.on { background: var(--tint); color: var(--navy); }
.nav form { margin: 0; }
.menu-btn { display: none; margin-left: auto; border: 1px solid var(--line); background: #fff; border-radius: 10px; padding: 8px 12px; font: inherit; }
@media (max-width: 1120px) {
  .menu-btn { display: inline-flex; align-items: center; gap: 6px; min-height: 44px; }
  .nav { display: none; position: absolute; left: 0; right: 0; top: 66px; flex-direction: column; align-items: stretch; background: #fff; border-bottom: 1px solid var(--line); padding: 8px var(--gutter) 16px; box-shadow: var(--shadow-lg); }
  .nav.open { display: flex; }
  .nav a, .nav .btn { padding: 12px; }
}

/* buttons, badges */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; min-height: 44px; padding: 10px 18px; border-radius: 12px; border: 1px solid transparent; font: 600 .97rem var(--font); text-decoration: none; cursor: pointer; transition: transform .15s, box-shadow .15s, background .15s; }
.btn:hover { transform: translateY(-1px); }
.btn-primary { background: var(--navy); color: #fff; box-shadow: 0 6px 18px rgba(26,0,170,.25); }
.btn-primary:hover { background: #12007A; }
.btn-orange { background: var(--orange); color: #fff; box-shadow: 0 6px 18px rgba(249,115,22,.28); }
.btn-ghost { background: #fff; color: var(--navy); border-color: #C7D2FE; }
.btn-ghost:hover { background: var(--tint); }
.btn-danger { background: #fff; color: var(--red); border-color: #FECACA; }
.btn-sm { min-height: 36px; padding: 6px 12px; font-size: .88rem; border-radius: 10px; }
.btn-block { width: 100%; }
.badge { display: inline-flex; align-items: center; padding: 2px 10px; border-radius: 99px; font-size: .78rem; font-weight: 600; white-space: nowrap; }
.b-ok { background: #DCFCE7; color: #166534; } .b-warn { background: #FEF3C7; color: #92400E; } .b-info { background: #E0E7FF; color: #3730A3; }
.b-bad { background: #FEE2E2; color: #991B1B; } .b-muted { background: #F1F5F9; color: #475569; } .b-done { background: #CCFBF1; color: #115E59; }
.chip { display: inline-block; padding: 3px 10px; border-radius: 99px; background: var(--tint); color: var(--navy); font-size: .8rem; font-weight: 600; margin: 2px 4px 2px 0; }

/* hero */
.hero { position: relative; overflow: hidden; background: radial-gradient(1200px 500px at 85% -10%, #E0DBFF 0%, transparent 60%), radial-gradient(800px 400px at -10% 110%, #FFEAD5 0%, transparent 55%), linear-gradient(180deg, #F7F6FF, #fff); padding: clamp(40px, 8vw, 90px) 0 clamp(36px, 6vw, 70px); }
.hero-grid { display: grid; grid-template-columns: 1.1fr .9fr; gap: 40px; align-items: center; }
@media (max-width: 900px) { .hero-grid { grid-template-columns: 1fr; } }
.eyebrow { display: inline-flex; align-items: center; gap: 8px; padding: 6px 12px; border-radius: 99px; background: #fff; border: 1px solid #DDD6FE; color: var(--navy); font-size: .82rem; font-weight: 700; letter-spacing: .02em; margin-bottom: 16px; }
.hero h1 em { font-style: normal; background: linear-gradient(90deg, var(--navy), #7C3AED); -webkit-background-clip: text; background-clip: text; color: transparent; }
.lead { font-size: clamp(1.02rem, 1.8vw, 1.18rem); color: #334155; max-width: 640px; }
.cta { display: flex; flex-wrap: wrap; gap: 12px; margin: 24px 0 18px; }
.ticks { list-style: none; padding: 0; margin: 0; display: flex; flex-wrap: wrap; gap: 8px 18px; color: #334155; font-size: .92rem; }
.ticks li::before { content: "✓"; color: var(--green); font-weight: 800; margin-right: 6px; }

/* platform cards (generic icons, names only: not affiliated with the platform owners) */
.platforms { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; }
.platform { background: rgba(255,255,255,.85); border: 1px solid #E4E2FB; border-radius: 18px; padding: 18px 14px; text-align: center; box-shadow: var(--shadow); }
.pi { display: inline-flex; width: 40px; height: 40px; flex-shrink: 0; vertical-align: middle; }
.pi svg { width: 100%; height: 100%; }
.platform .pi { display: flex; width: 54px; height: 54px; margin: 0 auto 10px; }
.platform b { display: block; color: var(--ink); font-size: .95rem; letter-spacing: .02em; }
.platform span { color: var(--muted); font-size: .78rem; }
.hero-card { background: #fff; border: 1px solid #E4E2FB; border-radius: 22px; padding: 20px; box-shadow: var(--shadow-lg); }
.hero-card h3 { font-size: 1rem; margin-bottom: 14px; }
.flow { list-style: none; margin: 18px 0 0; padding: 0; display: grid; gap: 10px; }
.flow li { display: grid; grid-template-columns: 34px 1fr; gap: 10px; align-items: start; font-size: .92rem; }
.flow li b { width: 30px; height: 30px; border-radius: 10px; display: grid; place-items: center; background: var(--tint); color: var(--navy); font-size: .85rem; }
@media (max-width: 520px) { .platforms { gap: 8px; } .platform { padding: 14px 6px; } .platform .pi { width: 42px; height: 42px; } .platform b { font-size: .8rem; } }

/* sections and cards */
.section { padding: clamp(44px, 7vw, 84px) 0; }
.section.soft { background: var(--soft); }
.section-head { max-width: 760px; margin: 0 auto 32px; text-align: center; }
.grid { display: grid; gap: 18px; }
.g2 { grid-template-columns: repeat(2, minmax(0, 1fr)); } .g3 { grid-template-columns: repeat(3, minmax(0, 1fr)); } .g4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
@media (max-width: 980px) { .g3, .g4 { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
@media (max-width: 640px) { .g2, .g3, .g4 { grid-template-columns: 1fr; } }
.card { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; box-shadow: var(--shadow); }
.card h3 { margin-bottom: .4em; }
.card .icon { width: 46px; height: 46px; border-radius: 12px; display: grid; place-items: center; background: var(--tint); color: var(--navy); margin-bottom: 14px; font-size: 1.3rem; }
.card.feature p { color: #475569; margin: 0; }
.steps { counter-reset: s; list-style: none; padding: 0; margin: 0; display: grid; gap: 14px; }
.steps li { counter-increment: s; position: relative; padding: 18px 18px 18px 68px; background: #fff; border: 1px solid var(--line); border-radius: var(--radius); }
.steps li::before { content: counter(s); position: absolute; left: 18px; top: 18px; width: 34px; height: 34px; border-radius: 10px; background: var(--navy); color: #fff; display: grid; place-items: center; font-weight: 700; }
.steps li b { display: block; color: var(--ink); }
.stat { text-align: center; }
.stat b { display: block; font-size: clamp(1.6rem, 3.5vw, 2.3rem); color: var(--navy); line-height: 1.1; }
.stat span { color: var(--muted); font-size: .9rem; }
.note { padding: 14px 16px; border-radius: 12px; background: #FFF7ED; border: 1px solid #FED7AA; color: #7C2D12; font-size: .93rem; }
.note.info { background: var(--tint); border-color: #C7D2FE; color: #1E1B4B; }
.note.ok { background: #ECFDF5; border-color: #A7F3D0; color: #064E3B; }
.prose { max-width: 820px; }
.prose h2 { margin-top: 1.8em; font-size: 1.4rem; }
.prose h3 { margin-top: 1.4em; }
.prose li { margin: .35em 0; }
.page-head { background: linear-gradient(180deg, #F6F5FD, #fff); border-bottom: 1px solid var(--line); padding: 34px 0 26px; }
.page-head p { color: var(--muted); max-width: 760px; margin: 0; }
.crumbs { font-size: .85rem; color: var(--muted); margin-bottom: 8px; }
.crumbs a { color: var(--muted); }

/* tables */
.table-wrap { overflow-x: auto; -webkit-overflow-scrolling: touch; border: 1px solid var(--line); border-radius: var(--radius); background: #fff; }
table { width: 100%; border-collapse: collapse; font-size: .93rem; }
th, td { padding: 10px 12px; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
th { background: #F8FAFC; color: #334155; font-weight: 600; white-space: nowrap; }
tr:last-child td { border-bottom: 0; }
td.num, th.num { text-align: right; font-variant-numeric: tabular-nums; white-space: nowrap; }
.price-table td:first-child { font-weight: 600; color: var(--ink); }

/* forms */
form.stack { display: grid; gap: 14px; }
label { display: block; font-weight: 600; color: var(--ink); font-size: .93rem; margin-bottom: 6px; }
.hint { display: block; font-weight: 400; color: var(--muted); font-size: .84rem; margin-top: 4px; }
input[type=text], input[type=email], input[type=password], input[type=number], input[type=url], input[type=date], input[type=tel], select, textarea {
  width: 100%; min-height: 44px; padding: 10px 12px; border: 1px solid #CBD5E1; border-radius: 10px; font: inherit; color: var(--text); background: #fff; }
textarea { min-height: 110px; resize: vertical; }
input:focus, select:focus, textarea:focus { border-color: var(--navy-2); outline: 3px solid #E0E7FF; }
.row2 { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
@media (max-width: 640px) { .row2 { grid-template-columns: 1fr; } }
.checks { display: grid; grid-template-columns: repeat(auto-fill, minmax(210px, 1fr)); gap: 6px 14px; }
.check { display: flex; gap: 8px; align-items: flex-start; font-weight: 400; font-size: .93rem; color: var(--text); margin: 0; }
.check input { margin-top: 4px; width: 18px; height: 18px; flex-shrink: 0; accent-color: var(--navy); }
fieldset { border: 1px solid var(--line); border-radius: var(--radius); padding: 16px; margin: 0; }
legend { padding: 0 6px; font-weight: 700; color: var(--ink); }
.auth { max-width: 460px; margin: 40px auto; }
.tabs { display: flex; gap: 6px; flex-wrap: wrap; margin-bottom: 16px; }
.tabs a { padding: 8px 14px; border-radius: 99px; border: 1px solid var(--line); text-decoration: none; color: var(--text); font-size: .9rem; }
.tabs a.on { background: var(--navy); border-color: var(--navy); color: #fff; }
.code { font: 600 1.05rem/1.3 ui-monospace, "Cascadia Mono", Consolas, monospace; letter-spacing: .06em; background: #0F172A; color: #E2E8F0; padding: 10px 14px; border-radius: 10px; display: inline-block; }
.mono { font-family: ui-monospace, Consolas, monospace; font-size: .88rem; }
.quote-box { position: sticky; top: 86px; }
.quote-total { font-size: 1.9rem; font-weight: 800; color: var(--navy); }

/* app layout */
.app { display: grid; grid-template-columns: 240px minmax(0, 1fr); gap: 28px; padding: 28px 0 60px; align-items: start; }
.side { position: sticky; top: 86px; display: grid; gap: 4px; }
.side a { padding: 10px 12px; border-radius: 10px; text-decoration: none; color: var(--text); font-weight: 500; }
.side a:hover, .side a.on { background: var(--tint); color: var(--navy); }
.side .group { margin: 12px 0 4px; font-size: .74rem; font-weight: 700; color: var(--muted); text-transform: uppercase; letter-spacing: .06em; padding: 0 12px; }
@media (max-width: 900px) { .app { grid-template-columns: 1fr; } .side { position: static; display: flex; overflow-x: auto; gap: 6px; padding-bottom: 4px; } .side .group { display: none; } .side a { white-space: nowrap; border: 1px solid var(--line); } }
.kpis { display: grid; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); gap: 12px; margin-bottom: 20px; }
.kpi { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 16px; }
.kpi b { display: block; font-size: 1.5rem; color: var(--ink); }
.kpi span { color: var(--muted); font-size: .85rem; }
.bar { height: 10px; border-radius: 99px; background: #EEF2FF; overflow: hidden; }
.bar i { display: block; height: 100%; background: linear-gradient(90deg, var(--navy), #7C3AED); }
.flash { margin: 16px 0; display: grid; gap: 8px; }
.flash div { padding: 12px 14px; border-radius: 12px; border: 1px solid; }
.flash .ok { background: #ECFDF5; border-color: #A7F3D0; color: #065F46; }
.flash .bad { background: #FEF2F2; border-color: #FECACA; color: #991B1B; }
.flash .info { background: #EEF2FF; border-color: #C7D2FE; color: #312E81; }
.actions { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
.actions form { margin: 0; }
details.box { border: 1px solid var(--line); border-radius: 12px; padding: 12px 16px; background: #fff; margin: 8px 0; }
details.box summary { cursor: pointer; font-weight: 600; color: var(--ink); }
.faq details { border: 1px solid var(--line); border-radius: 12px; padding: 14px 18px; background: #fff; margin: 10px 0; }
.faq summary { cursor: pointer; font-weight: 600; color: var(--ink); }
.faq details p { margin: .8em 0 0; color: #475569; }

/* footer */
.foot { background: #0B1033; color: #CBD5E1; padding: 48px 0 26px; margin-top: 40px; }
.foot a { color: #E2E8F0; text-decoration: none; }
.foot a:hover { text-decoration: underline; }
.foot-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr 1fr; gap: 24px; }
@media (max-width: 900px) { .foot-grid { grid-template-columns: 1fr 1fr; } }
@media (max-width: 560px) { .foot-grid { grid-template-columns: 1fr; } }
.foot h4 { color: #fff; font-size: .95rem; margin-bottom: 10px; }
.foot ul { list-style: none; padding: 0; margin: 0; display: grid; gap: 6px; font-size: .92rem; }
.foot .by { display: inline-flex; align-items: center; gap: 8px; padding: 6px 12px; border: 1px solid #2E356B; border-radius: 99px; font-size: .82rem; color: #E0E7FF; margin-top: 10px; }
.foot .legal { border-top: 1px solid #1F2757; margin-top: 30px; padding-top: 16px; font-size: .8rem; color: #94A3B8; display: flex; flex-wrap: wrap; justify-content: space-between; gap: 10px; }

/* form + quote side by side, stacked on small screens */
.split { display: grid; grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr); gap: 24px; align-items: start; }
@media (max-width: 900px) { .split { grid-template-columns: 1fr; } .quote-box { position: static; } }
.menu-btn { white-space: nowrap; }
@media (max-width: 430px) { .brand small { display: none; } .brand b { font-size: 1.05rem; } }