:root {
  --ink: #1d1a16;
  --ink-soft: #4a443c;
  --muted: #7a7166;
  --paper: #faf6ee;
  --paper-2: #f2ebde;
  --line: #e2d8c6;
  --red: #a8291f;
  --red-dark: #861f17;
  --gold: #b0894a;
  --white: #fff;
  --radius: 14px;
  --shadow: 0 1px 2px rgba(29, 26, 22, .05), 0 8px 24px rgba(29, 26, 22, .06);
  --serif: "Noto Serif", Georgia, serif;
  --sans: "Be Vietnam Pro", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 76px; }
body {
  margin: 0;
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.65;
  color: var(--ink);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; display: block; }
a { color: inherit; }
h1, h2, h3 { font-family: var(--serif); line-height: 1.25; margin: 0; letter-spacing: -.01em; }
h2 { font-size: clamp(1.7rem, 3.2vw, 2.4rem); }
h3 { font-size: 1.2rem; }
p { margin: 0; }

.container { width: 100%; max-width: 1140px; margin: 0 auto; padding: 0 20px; }

.eyebrow {
  font-size: .78rem; font-weight: 600; letter-spacing: .14em; text-transform: uppercase;
  color: var(--red); margin-bottom: 12px;
}

/* Buttons */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 14px 26px; border-radius: 999px; border: 1.5px solid var(--red);
  background: var(--red); color: var(--white); font: 600 1rem var(--sans);
  text-decoration: none; cursor: pointer; transition: background .2s, transform .2s;
}
.btn:hover { background: var(--red-dark); border-color: var(--red-dark); }
.btn:active { transform: translateY(1px); }
.btn:focus-visible, a:focus-visible, input:focus-visible, button:focus-visible { outline: 3px solid var(--gold); outline-offset: 2px; }
.btn-ghost { background: transparent; color: var(--ink); border-color: var(--ink); }
.btn-ghost:hover { background: var(--ink); color: var(--white); border-color: var(--ink); }
.btn-small { padding: 9px 18px; font-size: .9rem; }
.btn-block { width: 100%; }
.btn[disabled] { opacity: .6; cursor: wait; }

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(250, 246, 238, .92); backdrop-filter: saturate(1.4) blur(10px);
  border-bottom: 1px solid transparent; transition: border-color .2s;
}
.site-header.scrolled { border-bottom-color: var(--line); }
.header-inner { display: flex; align-items: center; justify-content: space-between; height: 68px; }
.brand { display: inline-flex; align-items: center; gap: 10px; text-decoration: none; }
.brand-mark {
  width: 36px; height: 36px; border-radius: 8px; background: var(--red); color: var(--paper);
  display: grid; place-items: center; font: 700 .85rem var(--serif); letter-spacing: .04em;
}
.brand-name { font: 700 1.25rem var(--serif); }
.site-nav { display: flex; align-items: center; gap: 26px; }
.site-nav a:not(.btn) { text-decoration: none; font-size: .95rem; font-weight: 500; color: var(--ink-soft); }
.site-nav a:not(.btn):hover { color: var(--red); }
.nav-toggle { display: none; background: none; border: 0; padding: 8px; cursor: pointer; }
.nav-toggle span { display: block; width: 22px; height: 2px; background: var(--ink); margin: 5px 0; transition: transform .2s, opacity .2s; }

/* Hero */
.hero {
  padding: 88px 0 96px;
  background:
    radial-gradient(1200px 500px at 85% -10%, rgba(168, 41, 31, .08), transparent 60%),
    radial-gradient(800px 400px at -10% 110%, rgba(176, 137, 74, .12), transparent 60%);
}
.hero-inner { max-width: 860px; }
.hero h1 { font-size: clamp(2.1rem, 5.2vw, 3.6rem); }
.hero h1 span { color: var(--red); }
.lead { font-size: 1.15rem; color: var(--ink-soft); margin-top: 22px; max-width: 700px; }
.hero-cta { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 32px; }
.hero-points { list-style: none; padding: 0; margin: 40px 0 0; display: flex; flex-wrap: wrap; gap: 10px 28px; color: var(--ink-soft); font-size: .98rem; }
.hero-points li::before { content: "—"; color: var(--gold); margin-right: 8px; }
.hero-points strong { color: var(--ink); }

/* Sections */
.section { padding: 88px 0; }
.section-alt { background: var(--paper-2); }
.section-head { margin-bottom: 40px; max-width: 680px; }
.grid { display: grid; gap: 20px; }
.services { grid-template-columns: repeat(2, 1fr); }
.projects { grid-template-columns: repeat(3, 1fr); }
.card {
  background: var(--white); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 28px; box-shadow: var(--shadow);
}
.card h3 { margin-bottom: 10px; }
.card p { color: var(--ink-soft); font-size: .98rem; }
.card-num { display: block; font: 600 .85rem var(--serif); color: var(--gold); margin-bottom: 14px; letter-spacing: .08em; }

/* Steps */
.steps { list-style: none; padding: 0; margin: 0; display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; counter-reset: s; }
.steps li { position: relative; padding-top: 8px; }
.steps li:not(:last-child)::after {
  content: ""; position: absolute; top: 30px; left: 56px; right: -10px; height: 1.5px;
  background: repeating-linear-gradient(90deg, var(--gold) 0 6px, transparent 6px 12px);
}
.step-num {
  width: 44px; height: 44px; border-radius: 50%; display: grid; place-items: center;
  background: var(--ink); color: var(--paper); font: 700 1.05rem var(--serif); margin-bottom: 18px;
}
.steps h3 { margin-bottom: 8px; }
.steps p { color: var(--ink-soft); font-size: .97rem; }

/* EduOS */
.eduos { display: grid; grid-template-columns: 1fr 1fr; gap: 56px; align-items: center; }
.eduos-text > p { color: var(--ink-soft); margin-top: 16px; }
.check-list { list-style: none; padding: 0; margin: 22px 0; }
.check-list li { padding-left: 30px; position: relative; margin: 8px 0; }
.check-list li::before {
  content: ""; position: absolute; left: 0; top: 7px; width: 18px; height: 18px; border-radius: 50%;
  background: var(--red) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16' fill='none' stroke='white' stroke-width='2.4'%3E%3Cpath d='M4 8.5l2.5 2.5L12 5.5'/%3E%3C/svg%3E") center/12px no-repeat;
}
.note { font-size: .9rem; color: var(--muted); border-left: 3px solid var(--gold); padding-left: 12px; }
.mock { background: var(--white); border: 1px solid var(--line); border-radius: 16px; box-shadow: 0 24px 60px rgba(29, 26, 22, .12); overflow: hidden; }
.mock-bar { display: flex; gap: 6px; padding: 12px 14px; border-bottom: 1px solid var(--line); background: var(--paper); }
.mock-bar i { width: 10px; height: 10px; border-radius: 50%; background: var(--line); }
.mock-body { display: grid; grid-template-columns: 70px 1fr; min-height: 260px; }
.mock-side { background: var(--ink); padding: 16px 12px; display: flex; flex-direction: column; gap: 12px; }
.mock-side b { height: 8px; border-radius: 4px; background: rgba(255, 255, 255, .22); }
.mock-side b:first-child { background: var(--red); }
.mock-main { padding: 18px; display: flex; flex-direction: column; gap: 16px; }
.mock-kpis { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; }
.mock-kpis span { height: 54px; border-radius: 10px; background: var(--paper-2); border: 1px solid var(--line); }
.mock-chart { flex: 1; display: flex; align-items: flex-end; gap: 10px; padding: 10px; border-radius: 10px; background: var(--paper); border: 1px solid var(--line); min-height: 140px; }
.mock-chart em { flex: 1; border-radius: 4px 4px 0 0; background: linear-gradient(var(--red), rgba(168, 41, 31, .55)); }

/* Projects */
.project-type { font-size: .78rem !important; font-weight: 600; text-transform: uppercase; letter-spacing: .1em; color: var(--gold) !important; margin-bottom: 10px; }
.placeholder { border-style: dashed; box-shadow: none; background: transparent; }
.placeholder h3 { color: var(--muted); }

/* Founder */
.founder { display: grid; grid-template-columns: 320px 1fr; gap: 56px; align-items: start; }
.founder-photo {
  aspect-ratio: 4 / 5; border-radius: 18px; overflow: hidden;
  background: linear-gradient(160deg, var(--ink), #3a3128); display: grid; place-items: center;
}
.founder-photo span { font: 700 3rem var(--serif); color: rgba(250, 246, 238, .25); letter-spacing: .1em; }
.founder-photo img { width: 100%; height: 100%; object-fit: cover; }
.founder-role { color: var(--red); font-weight: 600; margin: 6px 0 16px; }
.founder-text > p:not(.eyebrow):not(.founder-role) { color: var(--ink-soft); }
.timeline { list-style: none; padding: 0; margin: 28px 0 0; border-left: 2px solid var(--line); }
.timeline li { position: relative; padding: 0 0 18px 24px; }
.timeline li::before { content: ""; position: absolute; left: -7px; top: 8px; width: 12px; height: 12px; border-radius: 50%; background: var(--paper); border: 2px solid var(--red); }
.timeline span { display: block; font: 600 .85rem var(--serif); color: var(--gold); letter-spacing: .04em; }

/* Contact */
.section-dark { background: var(--ink); color: var(--paper); }
.section-dark .eyebrow { color: #e0a99f; }
.contact { display: grid; grid-template-columns: 1fr 1.1fr; gap: 56px; align-items: start; }
.contact-text > p { color: rgba(250, 246, 238, .75); margin-top: 16px; }
.contact-alt { list-style: none; padding: 0; margin: 28px 0 0; }
.contact-alt li { margin: 8px 0; }
.contact-alt a { color: var(--paper); text-decoration-color: rgba(250, 246, 238, .4); text-underline-offset: 3px; }
.lead-form { background: var(--paper); color: var(--ink); border-radius: 18px; padding: 32px; box-shadow: 0 24px 60px rgba(0, 0, 0, .25); }
.field { margin: 0 0 18px; border: 0; padding: 0; min-width: 0; }
.field-row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.field label, .field legend { display: block; font-weight: 600; font-size: .92rem; margin-bottom: 6px; padding: 0; }
.field em { color: var(--red); font-style: normal; }
.field input[type="text"], .field input[type="tel"] {
  width: 100%; padding: 12px 14px; border: 1.5px solid var(--line); border-radius: 10px;
  font: 400 1rem var(--sans); background: var(--white); color: var(--ink); transition: border-color .2s;
}
.field input:focus { border-color: var(--gold); outline: none; }
.field input::placeholder { color: #a99f92; font-size: .9rem; }
.field.invalid input[type="text"], .field.invalid input[type="tel"] { border-color: var(--red); }
.field .err { display: block; color: var(--red); font-size: .85rem; margin-top: 4px; }
.choices { display: flex; flex-wrap: wrap; gap: 10px; }
.choice { position: relative; cursor: pointer; }
.choice input { position: absolute; opacity: 0; inset: 0; cursor: pointer; }
.choice span {
  display: inline-block; padding: 10px 16px; border: 1.5px solid var(--line); border-radius: 999px;
  background: var(--white); font-size: .95rem; font-weight: 500; transition: all .15s;
}
.choice input:checked + span { border-color: var(--red); background: var(--red); color: var(--white); }
.choice input:focus-visible + span { outline: 3px solid var(--gold); outline-offset: 2px; }
.field.invalid .choice span { border-color: var(--red); }
.hp { position: absolute; left: -9999px; width: 1px; height: 1px; opacity: 0; }
.form-status { margin-top: 14px; font-size: .95rem; min-height: 1.4em; }
.form-status.ok { color: #2f6b3a; font-weight: 600; }
.form-status.fail { color: var(--red); }

/* Footer */
.site-footer { background: #141210; color: rgba(250, 246, 238, .7); padding: 40px 0; font-size: .92rem; }
.footer-inner { display: flex; justify-content: space-between; align-items: flex-end; gap: 24px; flex-wrap: wrap; }
.brand-light .brand-name { color: var(--paper); }
.footer-inner p { margin-top: 10px; }

/* Reveal */
.reveal { opacity: 0; transform: translateY(16px); transition: opacity .6s ease, transform .6s ease; }
.reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
}

/* Responsive */
@media (max-width: 960px) {
  .steps { grid-template-columns: repeat(2, 1fr); row-gap: 36px; }
  .steps li:nth-child(2)::after { display: none; }
  .eduos, .contact { grid-template-columns: 1fr; gap: 40px; }
  .founder { grid-template-columns: 240px 1fr; gap: 36px; }
  .projects { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 760px) {
  body { font-size: 16px; }
  .container { padding: 0 16px; }
  .nav-toggle { display: block; }
  .site-nav {
    position: absolute; top: 68px; left: 0; right: 0; flex-direction: column; align-items: stretch; gap: 0;
    background: var(--paper); border-bottom: 1px solid var(--line); padding: 8px 16px 18px;
    display: none;
  }
  .site-nav.open { display: flex; }
  .site-nav a:not(.btn) { padding: 12px 0; border-bottom: 1px solid var(--line); }
  .site-nav .btn { margin-top: 14px; }
  .nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
  .nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
  .nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }
  .hero { padding: 56px 0 64px; }
  .section { padding: 64px 0; }
  .services, .projects { grid-template-columns: 1fr; }
  .steps { grid-template-columns: 1fr; row-gap: 24px; }
  .steps li { display: grid; grid-template-columns: 44px 1fr; column-gap: 16px; padding-top: 0; }
  .steps li::after { display: none; }
  .step-num { grid-row: span 2; margin: 0; }
  .founder { grid-template-columns: 1fr; }
  .founder-photo { max-width: 220px; }
  .field-row { grid-template-columns: 1fr; gap: 0; }
  .lead-form { padding: 22px; }
  .card { padding: 22px; }
}

/* v2 · trường bổ sung, đồng ý, nút nổi, chân trang */
.field select, .field textarea {
  width: 100%; padding: 12px 14px; border: 1.5px solid var(--line); border-radius: 10px;
  font: 400 1rem var(--sans); background: var(--white); color: var(--ink);
}
.field textarea { resize: vertical; min-height: 88px; }
.field select:focus, .field textarea:focus { border-color: var(--gold); outline: none; }
.check { display: flex !important; gap: 10px; align-items: flex-start; font-weight: 400 !important; font-size: .9rem !important; line-height: 1.5; cursor: pointer; }
.check input { width: 18px; height: 18px; margin-top: 2px; accent-color: var(--red); flex: none; }
.check a { color: var(--red); }
.field.invalid .check span { color: var(--red); }
.footer-meta { text-align: right; }
.footer-contact { list-style: none; padding: 0; margin: 0 0 6px; }
.footer-contact li { margin: 2px 0; }
.footer-contact a, .copy a { color: var(--paper); text-underline-offset: 3px; }
.float-contact { position: fixed; right: 16px; bottom: 16px; z-index: 60; display: none; flex-direction: column; gap: 10px; }
.float-contact a { width: 56px; height: 56px; border-radius: 50%; display: grid; place-items: center; color: #fff; font: 700 .8rem var(--sans); text-decoration: none; box-shadow: 0 8px 20px rgba(0,0,0,.2); }
.fc-zalo { background: #0068ff; }
.fc-call { background: var(--red); }
@media (max-width: 760px) {
  .float-contact:not([hidden]) { display: flex; }
  .footer-meta { text-align: left; }
  .site-footer { padding-bottom: 150px; }
}
/* trang chính sách */
.legal { max-width: 760px; padding: 56px 0 80px; }
.legal h1 { font-size: clamp(1.8rem, 4vw, 2.4rem); margin-bottom: 8px; }
.legal h2 { font-size: 1.25rem; margin: 32px 0 10px; }
.legal p, .legal li { color: var(--ink-soft); }
.legal ul { padding-left: 20px; }
.legal .updated { color: var(--muted); font-size: .9rem; }