/* =================================================================
   Vũ Trọng Minh — R&D Marketing Strategist
   Luxury consulting theme · dark navy + gold · serif typography
   ================================================================= */

:root {
  --ink-900: #020617;
  --ink-800: #0F172A;
  --ink-700: #111827;
  --ink-600: #1e293b;
  --gold:    #D4AF37;
  --gold-soft: #e8cf7e;
  --text:    #e2e8f0;
  --text-dim:#94a3b8;
  --line:    rgba(212, 175, 55, 0.18);
  --line-soft: rgba(226, 232, 240, 0.08);
  --serif: Cambria, Georgia, "Times New Roman", "Noto Serif", serif;
  --radius: 4px;
  --maxw: 1200px;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
  font-family: var(--serif);
  background: var(--ink-900);
  color: var(--text);
  line-height: 1.7;
  font-size: 1.05rem;
  letter-spacing: 0.1px;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; height: auto; display: block; }
a { color: inherit; text-decoration: none; transition: color 0.25s var(--ease); }

.container { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }
.container.narrow { max-width: 820px; }

.skip-link {
  position: absolute; left: -999px; top: 0; z-index: 999;
  background: var(--gold); color: var(--ink-900); padding: 10px 18px;
}
.skip-link:focus { left: 12px; top: 12px; }

/* ---------- Typography ---------- */
h1, h2, h3, h4 { font-family: var(--serif); font-weight: 700; line-height: 1.15; letter-spacing: 0.2px; color: #f8fafc; }
h1 { font-size: clamp(2.4rem, 5.5vw, 4.1rem); }
h2 { font-size: clamp(1.9rem, 3.6vw, 2.9rem); }
h3 { font-size: clamp(1.2rem, 1.8vw, 1.5rem); }
p { color: var(--text); }
.gold { color: var(--gold); }

.eyebrow {
  text-transform: uppercase; letter-spacing: 4px; font-size: 0.74rem;
  color: var(--text-dim); margin-bottom: 18px;
}
.eyebrow.gold { color: var(--gold); }

/* ---------- Buttons ---------- */
.btn {
  display: inline-block; padding: 15px 30px; font-family: var(--serif);
  font-size: 0.95rem; letter-spacing: 1.4px; text-transform: uppercase;
  border: 1px solid var(--gold); border-radius: var(--radius);
  cursor: pointer; transition: all 0.3s var(--ease); position: relative;
}
.btn-gold { background: var(--gold); color: var(--ink-900); font-weight: 700; }
.btn-gold:hover { background: var(--gold-soft); box-shadow: 0 12px 34px rgba(212,175,55,0.28); transform: translateY(-2px); }
.btn-ghost { background: transparent; color: var(--gold); }
.btn-ghost:hover { background: rgba(212,175,55,0.1); transform: translateY(-2px); }
.btn-block { display: block; width: 100%; text-align: center; }

/* ---------- Header / Nav ---------- */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(2, 6, 23, 0.82); backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line-soft);
}
.nav-wrap { display: flex; align-items: center; justify-content: space-between; height: 78px; }
.brand { display: flex; align-items: center; gap: 12px; }
.brand-mark {
  display: inline-grid; place-items: center; width: 42px; height: 42px;
  border: 1px solid var(--gold); color: var(--gold); border-radius: var(--radius);
  font-weight: 700; letter-spacing: 1px; font-size: 0.95rem;
}
.brand-mark.big { width: 56px; height: 56px; font-size: 1.2rem; }
.brand-text { font-size: 1.15rem; letter-spacing: 0.5px; color: #f8fafc; }
.main-nav ul { display: flex; align-items: center; gap: 30px; list-style: none; }
.main-nav a { font-size: 0.95rem; letter-spacing: 0.6px; color: var(--text-dim); }
.main-nav a:hover { color: var(--gold); }
.nav-cta { border: 1px solid var(--gold); color: var(--gold) !important; padding: 9px 20px; border-radius: var(--radius); }
.nav-cta:hover { background: var(--gold); color: var(--ink-900) !important; }

.nav-toggle { display: none; flex-direction: column; gap: 5px; background: none; border: none; cursor: pointer; padding: 8px; }
.nav-toggle span { width: 26px; height: 2px; background: var(--gold); transition: 0.3s var(--ease); }
.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ---------- Sections ---------- */
.section { padding: 110px 0; position: relative; }
.section-alt { background: linear-gradient(180deg, var(--ink-800), var(--ink-900)); border-top: 1px solid var(--line-soft); border-bottom: 1px solid var(--line-soft); }
.section-head { max-width: 780px; margin: 0 auto 64px; text-align: center; }
.section-intro { color: var(--text-dim); font-size: 1.12rem; margin-top: 18px; }
.two-col { display: grid; grid-template-columns: 1.15fr 0.85fr; gap: 64px; align-items: start; }

/* ---------- Hero ---------- */
.hero { position: relative; padding: 80px 0 0; overflow: hidden;
  background: radial-gradient(1200px 600px at 80% -10%, rgba(212,175,55,0.10), transparent 60%), var(--ink-900); }
.hero-glow { position: absolute; inset: 0; background:
  radial-gradient(600px 400px at 15% 20%, rgba(15,23,42,0.9), transparent 70%); pointer-events: none; }
.hero-grid { display: grid; grid-template-columns: 1.1fr 0.9fr; gap: 56px; align-items: center; padding-bottom: 70px; position: relative; z-index: 2; }
.hero-lead { font-size: 1.22rem; color: var(--text-dim); max-width: 620px; margin: 26px 0 36px; }
.hero-lead strong { color: var(--text); }
.hero-actions { display: flex; gap: 18px; flex-wrap: wrap; margin-bottom: 54px; }
.hero-stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; list-style: none; border-top: 1px solid var(--line); padding-top: 32px; }
.hero-stats li { display: flex; flex-direction: column; }
.stat-num, .stat-suffix { font-size: clamp(1.8rem, 3vw, 2.6rem); color: var(--gold); font-weight: 700; display: inline; }
.stat-suffix { font-size: 1.6rem; }
.stat-label { font-size: 0.82rem; color: var(--text-dim); letter-spacing: 0.4px; margin-top: 6px; }

.hero-portrait { position: relative; }
.hero-portrait img {
  border-radius: var(--radius); border: 1px solid var(--line);
  box-shadow: 0 30px 80px rgba(0,0,0,0.6), 0 0 0 1px rgba(212,175,55,0.06);
  object-fit: cover; width: 100%; aspect-ratio: 3/4;
}
.hero-portrait::before {
  content: ""; position: absolute; inset: -14px -14px 18px 18px;
  border: 1px solid var(--gold); border-radius: var(--radius); z-index: -1; opacity: 0.5;
}
.hero-portrait figcaption { text-align: center; color: var(--text-dim); font-size: 0.86rem; margin-top: 16px; letter-spacing: 0.4px; }

/* ---------- Marquee ---------- */
.marquee { border-top: 1px solid var(--line-soft); border-bottom: 1px solid var(--line-soft); overflow: hidden; padding: 18px 0; background: var(--ink-800); }
.marquee-track { display: flex; gap: 26px; white-space: nowrap; width: max-content; animation: scroll 38s linear infinite; }
.marquee-track span { color: var(--text-dim); letter-spacing: 2px; text-transform: uppercase; font-size: 0.86rem; }
.marquee-track span:nth-child(3n+1) { color: var(--gold); }
@keyframes scroll { to { transform: translateX(-50%); } }

/* ---------- About ---------- */
.about-card { background: var(--ink-700); border: 1px solid var(--line); border-radius: var(--radius); padding: 38px; position: sticky; top: 100px; }
.about-card h3 { margin-bottom: 22px; color: var(--gold); }
.spec-list { display: grid; gap: 14px; margin-bottom: 30px; }
.spec-list > div { display: flex; justify-content: space-between; gap: 16px; padding-bottom: 12px; border-bottom: 1px solid var(--line-soft); }
.spec-list dt { color: var(--text-dim); font-size: 0.92rem; }
.spec-list dd { text-align: right; color: var(--text); font-size: 0.95rem; }
.pull-quote { margin-top: 32px; padding: 24px 30px; border-left: 3px solid var(--gold); font-size: 1.3rem; font-style: italic; color: var(--gold-soft); background: rgba(212,175,55,0.05); }
.section p + p { margin-top: 18px; }

/* ---------- Process / R&D ---------- */
.process-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; list-style: none; counter-reset: none; }
.process-card { background: var(--ink-900); border: 1px solid var(--line-soft); border-radius: var(--radius); padding: 34px 28px; transition: all 0.35s var(--ease); }
.process-card:hover { border-color: var(--gold); transform: translateY(-6px); box-shadow: 0 22px 50px rgba(0,0,0,0.4); }
.process-num { display: block; font-size: 2.4rem; color: var(--gold); font-weight: 700; margin-bottom: 14px; opacity: 0.85; }
.process-card h3 { margin-bottom: 12px; }
.process-card p { color: var(--text-dim); font-size: 0.98rem; }

/* ---------- Card grids ---------- */
.card-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 26px; }
.feature-card { background: var(--ink-700); border: 1px solid var(--line-soft); border-radius: var(--radius); padding: 34px 30px; transition: all 0.35s var(--ease); }
.feature-card:hover { border-color: var(--gold); transform: translateY(-5px); }
.feature-card h3 { color: var(--gold-soft); margin-bottom: 14px; }
.feature-card p { color: var(--text-dim); font-size: 0.98rem; }

/* ---------- Services ---------- */
.services .service-card { background: var(--ink-700); border: 1px solid var(--line-soft); border-radius: var(--radius); padding: 36px 30px; position: relative; transition: all 0.35s var(--ease); }
.service-card:hover { border-color: var(--gold); transform: translateY(-5px); box-shadow: 0 22px 50px rgba(0,0,0,0.35); }
.service-card.featured { border-color: var(--gold); background: linear-gradient(160deg, rgba(212,175,55,0.08), var(--ink-700)); }
.service-card h3 { margin-bottom: 14px; color: #f8fafc; }
.service-card p { color: var(--text-dim); font-size: 0.97rem; margin-bottom: 20px; }
.badge { position: absolute; top: -12px; right: 24px; background: var(--gold); color: var(--ink-900); font-size: 0.68rem; letter-spacing: 1.5px; text-transform: uppercase; padding: 6px 14px; border-radius: 40px; font-weight: 700; }
.ticks { list-style: none; display: grid; gap: 10px; }
.ticks li { padding-left: 26px; position: relative; font-size: 0.94rem; color: var(--text); }
.ticks li::before { content: "✦"; position: absolute; left: 0; color: var(--gold); }

/* ---------- Timeline ---------- */
.timeline { list-style: none; max-width: 820px; margin: 0 auto; position: relative; padding-left: 30px; }
.timeline::before { content: ""; position: absolute; left: 6px; top: 6px; bottom: 6px; width: 1px; background: var(--line); }
.timeline-item { position: relative; padding: 0 0 42px 30px; }
.timeline-item::before { content: ""; position: absolute; left: -29px; top: 8px; width: 12px; height: 12px; border-radius: 50%; background: var(--gold); box-shadow: 0 0 0 5px rgba(212,175,55,0.15); }
.timeline-year { color: var(--gold); font-size: 0.86rem; letter-spacing: 2px; text-transform: uppercase; }
.timeline-item h3 { margin: 8px 0 10px; }
.timeline-item p { color: var(--text-dim); font-size: 0.98rem; }

/* ---------- Skills ---------- */
.skills-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 26px; }
.skill-group { background: var(--ink-900); border: 1px solid var(--line-soft); border-radius: var(--radius); padding: 30px; }
.skill-group h3 { color: var(--gold); font-size: 1.15rem; margin-bottom: 18px; }
.tag-list { list-style: none; display: flex; flex-wrap: wrap; gap: 10px; }
.tag-list li { border: 1px solid var(--line); border-radius: 40px; padding: 7px 16px; font-size: 0.85rem; color: var(--text); transition: all 0.25s var(--ease); }
.tag-list li:hover { background: rgba(212,175,55,0.12); border-color: var(--gold); }

/* ---------- Achievements ---------- */
.stat-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 26px; }
.big-stat { background: var(--ink-700); border: 1px solid var(--line-soft); border-radius: var(--radius); padding: 40px 32px; text-align: center; transition: all 0.35s var(--ease); }
.big-stat:hover { border-color: var(--gold); transform: translateY(-5px); }
.big-num { display: block; font-size: clamp(2.4rem, 4vw, 3.4rem); color: var(--gold); font-weight: 700; margin-bottom: 12px; }
.big-label { color: var(--text-dim); font-size: 0.96rem; }

/* ---------- Case Studies ---------- */
.case { background: var(--ink-700); border: 1px solid var(--line-soft); border-radius: var(--radius); padding: 44px; margin-bottom: 30px; transition: border-color 0.35s var(--ease); }
.case:hover { border-color: var(--line); }
.case-tag { color: var(--gold); font-size: 0.78rem; letter-spacing: 2px; text-transform: uppercase; margin-bottom: 14px; }
.case > h3 { font-size: clamp(1.4rem, 2.2vw, 1.9rem); margin-bottom: 28px; }
.case-body { display: grid; grid-template-columns: 1.3fr 0.7fr; gap: 44px; }
.case-body h4 { color: var(--gold-soft); font-size: 1rem; letter-spacing: 0.5px; margin: 0 0 8px; text-transform: uppercase; }
.case-body h4 + p { margin-bottom: 20px; }
.case-body p { color: var(--text-dim); font-size: 0.98rem; }
.result-list { list-style: none; display: grid; gap: 14px; margin-bottom: 18px; }
.result-list li { padding: 14px 18px; background: var(--ink-900); border-left: 3px solid var(--gold); border-radius: var(--radius); font-size: 0.98rem; }
.result-list strong { color: var(--gold); font-size: 1.25rem; margin-right: 6px; }
.case-note { font-style: italic; color: var(--text-dim) !important; }

/* ---------- Testimonials ---------- */
.testimonials .testimonial { background: var(--ink-700); border: 1px solid var(--line-soft); border-radius: var(--radius); padding: 36px 32px; display: flex; flex-direction: column; }
.testimonial blockquote { font-style: italic; font-size: 1.08rem; color: var(--text); margin-bottom: 22px; position: relative; padding-top: 28px; }
.testimonial blockquote::before { content: "“"; position: absolute; top: -10px; left: -4px; font-size: 3.4rem; color: var(--gold); opacity: 0.5; line-height: 1; }
.testimonial figcaption { margin-top: auto; }
.t-name { display: block; color: var(--gold-soft); font-weight: 700; }
.t-role { display: block; color: var(--text-dim); font-size: 0.86rem; }

/* ---------- Blog ---------- */
.blog .blog-card { background: var(--ink-700); border: 1px solid var(--line-soft); border-radius: var(--radius); padding: 32px 28px; display: flex; flex-direction: column; transition: all 0.35s var(--ease); }
.blog-card:hover { border-color: var(--gold); transform: translateY(-5px); }
.blog-meta { color: var(--gold); font-size: 0.76rem; letter-spacing: 1.5px; text-transform: uppercase; margin-bottom: 14px; }
.blog-card h3 { margin-bottom: 14px; }
.blog-card p { color: var(--text-dim); font-size: 0.96rem; margin-bottom: 20px; }
.read-more { color: var(--gold); font-size: 0.92rem; letter-spacing: 0.5px; margin-top: auto; }
.read-more:hover { color: var(--gold-soft); }

/* ---------- FAQ ---------- */
.faq-list { display: grid; gap: 14px; }
.faq-item { background: var(--ink-700); border: 1px solid var(--line-soft); border-radius: var(--radius); padding: 0 28px; transition: border-color 0.3s var(--ease); }
.faq-item[open] { border-color: var(--line); }
.faq-item summary { cursor: pointer; padding: 24px 0; font-size: 1.1rem; color: #f8fafc; list-style: none; position: relative; padding-right: 40px; }
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after { content: "+"; position: absolute; right: 0; top: 50%; transform: translateY(-50%); color: var(--gold); font-size: 1.6rem; transition: transform 0.3s var(--ease); }
.faq-item[open] summary::after { transform: translateY(-50%) rotate(45deg); }
.faq-item p { color: var(--text-dim); padding-bottom: 24px; font-size: 0.99rem; }
.faq-item a { color: var(--gold); }

/* ---------- Contact ---------- */
.section-contact { background: linear-gradient(180deg, var(--ink-800), var(--ink-900)); border-top: 1px solid var(--line); }
.contact-grid { align-items: start; }
.contact-list { list-style: none; display: grid; gap: 18px; margin: 30px 0; }
.contact-list li { display: flex; flex-direction: column; gap: 4px; border-bottom: 1px solid var(--line-soft); padding-bottom: 14px; }
.contact-label { color: var(--gold); font-size: 0.76rem; letter-spacing: 2px; text-transform: uppercase; }
.contact-list a:hover { color: var(--gold); }
.offer-box { background: rgba(212,175,55,0.07); border: 1px solid var(--line); border-radius: var(--radius); padding: 26px 28px; margin-top: 8px; }
.offer-box h3 { color: var(--gold); margin-bottom: 10px; font-size: 1.2rem; }
.offer-box p { color: var(--text-dim); font-size: 0.96rem; }

/* ---------- Form ---------- */
.form-wrap { background: var(--ink-700); border: 1px solid var(--line); border-radius: var(--radius); padding: 40px; }
.field { margin-bottom: 22px; }
.field label { display: block; margin-bottom: 8px; font-size: 0.9rem; color: var(--text-dim); letter-spacing: 0.5px; }
.field label span { color: var(--gold); }
.field input, .field select, .field textarea {
  width: 100%; background: var(--ink-900); border: 1px solid var(--line-soft);
  border-radius: var(--radius); padding: 14px 16px; color: var(--text);
  font-family: var(--serif); font-size: 1rem; transition: border-color 0.25s var(--ease);
}
.field input:focus, .field select:focus, .field textarea:focus { outline: none; border-color: var(--gold); box-shadow: 0 0 0 3px rgba(212,175,55,0.12); }
.field textarea { resize: vertical; }
.field.invalid input, .field.invalid textarea { border-color: #f87171; }
.error { color: #f87171; font-size: 0.82rem; display: block; margin-top: 6px; min-height: 1em; }
.hp { position: absolute; left: -9999px; width: 1px; height: 1px; opacity: 0; }
.form-fineprint { font-size: 0.8rem; color: var(--text-dim); text-align: center; margin-top: 16px; }
#submit-btn[disabled] { opacity: 0.6; cursor: not-allowed; }

/* ---------- Footer ---------- */
.site-footer { background: var(--ink-900); border-top: 1px solid var(--line); padding: 70px 0 30px; }
.footer-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr; gap: 40px; padding-bottom: 40px; border-bottom: 1px solid var(--line-soft); }
.footer-name { font-size: 1.3rem; color: #f8fafc; margin-top: 16px; }
.footer-tag { color: var(--text-dim); font-size: 0.92rem; margin-top: 6px; }
.site-footer h4 { color: var(--gold); margin-bottom: 18px; font-size: 1rem; letter-spacing: 1px; }
.site-footer ul { list-style: none; display: grid; gap: 12px; }
.site-footer a { color: var(--text-dim); font-size: 0.95rem; }
.site-footer a:hover { color: var(--gold); }
.footer-bottom { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 12px; padding-top: 26px; color: var(--text-dim); font-size: 0.84rem; }

/* ---------- Modal ---------- */
.modal { position: fixed; inset: 0; z-index: 1000; display: grid; place-items: center; background: rgba(2,6,23,0.85); backdrop-filter: blur(6px); padding: 24px; animation: fade 0.3s var(--ease); }
.modal[hidden] { display: none; }
.modal-card { background: var(--ink-700); border: 1px solid var(--gold); border-radius: var(--radius); padding: 48px 40px; max-width: 460px; text-align: center; box-shadow: 0 30px 80px rgba(0,0,0,0.6); }
.modal-check { width: 70px; height: 70px; margin: 0 auto 22px; border-radius: 50%; background: var(--gold); color: var(--ink-900); display: grid; place-items: center; font-size: 2.2rem; font-weight: 700; }
.modal-card h3 { margin-bottom: 14px; }
.modal-card p { color: var(--text-dim); margin-bottom: 28px; }
@keyframes fade { from { opacity: 0; } to { opacity: 1; } }

/* ---------- Reveal animations ---------- */
.reveal { opacity: 0; transform: translateY(28px); transition: opacity 0.7s var(--ease), transform 0.7s var(--ease); }
.reveal.in { opacity: 1; transform: none; }

/* ---------- Responsive ---------- */
@media (max-width: 980px) {
  .two-col, .hero-grid, .case-body, .contact-grid { grid-template-columns: 1fr; gap: 40px; }
  .about-card { position: static; }
  .process-grid, .card-grid, .skills-grid, .stat-grid, .footer-grid { grid-template-columns: repeat(2, 1fr); }
  .hero-portrait { max-width: 420px; margin: 0 auto; }
  .section { padding: 80px 0; }
}
@media (max-width: 640px) {
  .main-nav { position: fixed; inset: 78px 0 auto; background: var(--ink-800); border-bottom: 1px solid var(--line); transform: translateY(-130%); transition: transform 0.4s var(--ease); padding: 20px 0; }
  .main-nav.open { transform: translateY(0); }
  .main-nav ul { flex-direction: column; gap: 4px; }
  .main-nav a { display: block; padding: 14px 24px; }
  .nav-toggle { display: flex; }
  .process-grid, .card-grid, .skills-grid, .stat-grid, .footer-grid { grid-template-columns: 1fr; }
  .hero-stats { grid-template-columns: 1fr; gap: 16px; }
  .case { padding: 28px 22px; }
  .form-wrap, .about-card { padding: 28px 22px; }
  .footer-bottom { flex-direction: column; }
}

@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
  .reveal { opacity: 1; transform: none; }
  html { scroll-behavior: auto; }
}