/* Khung và màu bám theo website Adxchange: đen #0a0a0c, trắng, đỏ ruby #1d4ed8, xám ấm #f4f2f0 */
:root {
  --ink: #0a0a0c;
  --paper: #fff;
  --ruby: #1d4ed8;
  --ruby-d: #1e3a8a;
  --warm: #f4f2f0;
  --line: #e6e6e6;
  --font: "Inter Tight", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body { font-family: var(--font); background: var(--paper); color: var(--ink); line-height: 1.3; -webkit-font-smoothing: antialiased; overflow-x: hidden; }
a { color: inherit; text-decoration: none; }
img, video { display: block; max-width: 100%; }
ul, ol { list-style: none; }
button { font: inherit; color: inherit; }
h1, h2, h3, h4, h5 { font-weight: 500; }

.skip-link { position: absolute; left: -999px; top: 8px; z-index: 300; background: #fff; color: #000; padding: 10px 16px; border-radius: 8px; }
.skip-link:focus { left: 8px; }

/* ---------- Header ---------- */
.logo-fixed { position: fixed; top: 12px; left: 16px; z-index: 110; }
.logo-fixed img { height: 46px; width: auto; border-radius: 10px; }
.adx-h { position: fixed; top: 0; left: 0; right: 0; z-index: 100; display: grid; grid-template-columns: 1fr auto 1fr; align-items: center; gap: 16px; padding: 12px 16px; color: #fff; mix-blend-mode: difference; pointer-events: none; }
.adx-h > * { pointer-events: auto; }
.adx-h nav { display: flex; gap: 28px; font-size: 12px; letter-spacing: .06em; text-transform: uppercase; }
.adx-h nav a { opacity: .65; transition: opacity .2s; }
.adx-h nav a:hover, .adx-h nav a.on { opacity: 1; }
.hr { justify-self: end; display: flex; align-items: center; gap: 10px; }
.hcta { font-size: 11px; letter-spacing: .06em; text-transform: uppercase; border: 1px solid #fff; border-radius: 99px; padding: 6px 14px; }
.hcta:hover { background: #fff; color: #000; }
.burger { display: none; background: none; border: 0; width: 36px; height: 32px; position: relative; cursor: pointer; }
.burger span { position: absolute; left: 6px; right: 6px; height: 2px; background: #fff; transition: transform .25s, top .25s; }
.burger span:nth-child(1) { top: 10px; }
.burger span:nth-child(2) { top: 19px; }
.burger.open span:nth-child(1) { top: 14px; transform: rotate(45deg); }
.burger.open span:nth-child(2) { top: 14px; transform: rotate(-45deg); }
.nav-mobile { position: fixed; inset: 0; z-index: 90; background: var(--ink); color: #fff; display: flex; flex-direction: column; justify-content: center; align-items: flex-start; gap: 14px; padding: 0 20px; font-size: clamp(40px, 12vw, 72px); font-weight: 500; letter-spacing: -.05em; line-height: 1; transform: translateY(-100%); visibility: hidden; transition: transform .45s ease, visibility .45s; }
.nav-mobile.open { transform: none; visibility: visible; }
.nav-mobile a.on { color: var(--ruby); }

/* ---------- Khối full màn hình ---------- */
.full { min-height: 100vh; min-height: 100svh; position: relative; display: flex; align-items: center; justify-content: center; overflow: hidden; }

.hero { background: #000; color: #fff; flex-direction: column; }
.hero video { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; opacity: .75; }
.hero::after { content: ""; position: absolute; inset: 0; background: linear-gradient(rgba(0, 0, 0, .35), rgba(0, 0, 0, .1) 40%, rgba(29, 78, 216, .35)); }
.hero .tag, .hero h2, .pill { position: relative; z-index: 2; }
.tag { font-size: 11px; letter-spacing: .08em; text-transform: uppercase; }
.hero .tag { margin-bottom: 1vh; }
.hero h2 { font-size: clamp(44px, 15vw, 300px); font-weight: 500; line-height: 1; letter-spacing: -.05em; white-space: nowrap; }
.pill { position: absolute; bottom: 34px; left: 50%; transform: translateX(-50%); background: #000; color: #fff; font-size: 10px; text-transform: uppercase; letter-spacing: .06em; padding: 9px 18px; border-radius: 99px; white-space: nowrap; }
.pill:hover { background: var(--ruby); }

.statement { background: var(--ink); color: #fff; text-align: center; padding: 0 4vw; }
.statement::before { content: ""; position: absolute; inset: 0; background: radial-gradient(at 12% 50%, rgba(29, 78, 216, .7), transparent 30%), radial-gradient(at 92% 40%, rgba(29, 78, 216, .45), transparent 28%); }
.statement > div { position: relative; }
.statement p { font-size: clamp(34px, 6.2vw, 100px); font-weight: 500; line-height: 1.06; letter-spacing: -.03em; max-width: 1350px; margin: 0 auto; }
.statement em { font-style: normal; color: var(--ruby); background: #fff; padding: 0 .15em; border-radius: .1em; }
.s-link { display: inline-block; margin-top: 5vh; font-size: 14px; letter-spacing: -.01em; border-bottom: 1px solid var(--ruby); padding-bottom: 3px; }
.s-link:hover { color: var(--ruby); }
.s-link.dark { margin-top: 28px; }

.stats { display: grid; border-top: 1px solid var(--line); }
.stats div { padding: 56px 20px; border-right: 1px solid var(--line); }
.stats div:last-child { border: 0; }
.stats b { display: block; font-size: clamp(34px, 4.4vw, 72px); font-weight: 500; letter-spacing: -.05em; line-height: 1; color: var(--ruby); }
.stats span { display: block; margin-top: 10px; font-size: 13px; color: #555; max-width: 260px; }

.pillar { background: #fff; }
.pillar h3 { position: relative; z-index: 2; font-size: clamp(44px, 15vw, 280px); font-weight: 500; letter-spacing: -.05em; line-height: 1; white-space: nowrap; }
.pillar p { position: absolute; z-index: 2; left: 20px; bottom: 24px; max-width: 320px; font-size: 12px; line-height: 1.35; font-weight: 600; letter-spacing: -.01em; }
.pillar.img { color: #fff; background: #000; }
.pillar.img picture, .pillar.img img { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; opacity: .7; }

/* ---------- Section thường ---------- */
.sec { padding: 14vh 20px; }
.sec-tint { background: var(--warm); }
.sec h2 { font-size: clamp(48px, 9vw, 150px); font-weight: 700; letter-spacing: -.05em; line-height: .95; margin-bottom: 8vh; }
.sec .intro { max-width: 760px; font-size: clamp(18px, 1.8vw, 26px); line-height: 1.25; margin: -4vh 0 7vh; color: #333; }

.svc { border-top: 1px solid #111; }
.svc > div, .svc > a { display: grid; grid-template-columns: 70px 1.1fr 2fr; gap: 20px; padding: 30px 0; border-bottom: 1px solid #111; align-items: start; transition: background .3s, color .3s, padding .3s; }
.svc > div:hover, .svc > a:hover { background: var(--ruby); color: #fff; padding-left: 14px; padding-right: 14px; }
.svc small { font-size: 13px; opacity: .6; }
.svc h4 { font-size: clamp(22px, 2.6vw, 40px); font-weight: 500; line-height: 1.05; letter-spacing: -.02em; }
.svc p { font-size: 15px; line-height: 1.4; max-width: 560px; }
.svc.plain > div { grid-template-columns: 70px 1fr; }
.svc.plain p { font-size: clamp(17px, 1.6vw, 22px); max-width: 820px; }
.svc.contact p { font-size: clamp(18px, 1.8vw, 26px); }
.svc.contact a:hover { color: var(--ruby); }
.svc.contact > div:hover { color: inherit; background: transparent; padding-left: 0; padding-right: 0; }
.svc.contact > div:hover small { color: var(--ruby); }

/* ---------- Dự án ---------- */
.work { background: var(--ink); color: #fff; }
.work h2 { color: #fff; }
.cards { display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px; }
.card { position: relative; display: block; aspect-ratio: 16 / 10; overflow: hidden; background: #1a1a1e; }
.card.wide { grid-column: 1 / -1; aspect-ratio: 21 / 9; }
.card img { width: 100%; height: 100%; object-fit: cover; transition: transform .8s; }
.card:hover img { transform: scale(1.04); }
.card::after { content: ""; position: absolute; inset: 0; background: linear-gradient(0deg, rgba(0, 0, 0, .75), transparent 55%); }
.card .go { position: absolute; z-index: 2; top: 16px; right: 16px; width: 36px; height: 36px; border-radius: 50%; background: #fff; color: var(--ink); display: grid; place-items: center; font-size: 16px; transition: background .25s, color .25s; }
.card:hover .go { background: var(--ruby); color: #fff; }
.card .meta { position: absolute; z-index: 2; left: 20px; right: 20px; bottom: 20px; }
.card .meta small { font-size: 11px; text-transform: uppercase; letter-spacing: .07em; opacity: .8; }
.card .meta .h { font-size: clamp(22px, 2.6vw, 40px); font-weight: 500; line-height: 1.05; margin: 4px 0 6px; letter-spacing: -.02em; }
.card .meta p { font-size: 14px; max-width: 620px; line-height: 1.35; opacity: .9; }
.work .all { display: inline-block; margin-top: 40px; font-size: clamp(22px, 3vw, 44px); letter-spacing: -.04em; border-bottom: 2px solid var(--ruby); padding-bottom: 4px; }
.work .all:hover { color: var(--ruby); }
.all.dark { display: inline-block; margin-top: 40px; font-size: clamp(22px, 3vw, 44px); letter-spacing: -.04em; border-bottom: 2px solid var(--ruby); padding-bottom: 4px; }
.all.dark:hover { color: var(--ruby); }
.phero + .work { padding-top: 4vh; }

/* ---------- Đối tác ---------- */
.clients { padding: 10vh 0; border-bottom: 1px solid var(--line); overflow: hidden; }
.clients h3 { font-size: 12px; text-transform: uppercase; letter-spacing: .08em; margin: 0 20px 28px; color: #777; font-weight: 500; }
.mq { overflow: hidden; mask-image: linear-gradient(90deg, transparent, #000 8%, #000 92%, transparent); }
.mq-t { display: flex; width: max-content; gap: 48px; padding-right: 48px; animation: mq 40s linear infinite; }
.mq:hover .mq-t { animation-play-state: paused; }
.mq-i { flex: 0 0 auto; display: flex; align-items: center; justify-content: center; height: 64px; font-size: 22px; letter-spacing: -.02em; white-space: nowrap; color: #111; }
.mq-i img { height: 100%; width: auto; max-width: 150px; object-fit: contain; }
@keyframes mq { to { transform: translateX(-50%); } }
.tier { margin-bottom: 8vh; }
.tier h3 { font-size: 12px; text-transform: uppercase; letter-spacing: .08em; color: #777; margin-bottom: 24px; font-weight: 500; }
.tier-logos { display: flex; flex-wrap: wrap; gap: 28px 56px; align-items: center; }
.tier.t0 .mq-i { height: 120px; } .tier.t0 .mq-i img { max-width: 280px; }
.tier.t1 .mq-i { height: 96px; } .tier.t1 .mq-i img { max-width: 220px; }
.tier.t2 .mq-i { height: 76px; }
.tier.t3 .mq-i { height: 60px; }

/* ---------- Về SIV ---------- */
.about { display: grid; grid-template-columns: 1fr 1fr; gap: 6vw; }
.about .l p { font-size: clamp(20px, 2vw, 30px); line-height: 1.25; max-width: 640px; letter-spacing: -.01em; }
.about .l p + p { margin-top: 20px; }
.about .l h2 { margin-bottom: 4vh; }
.vm { display: grid; gap: 26px; align-content: start; }
.vm h5 { font-size: 11px; text-transform: uppercase; letter-spacing: .08em; color: var(--ruby); margin-bottom: 6px; font-weight: 500; }
.vm p { font-size: 17px; line-height: 1.35; }

/* ---------- FAQ ---------- */
.faq { background: var(--warm); }
.faq details { border-top: 1px solid #111; padding: 22px 0; }
.faq details:last-child { border-bottom: 1px solid #111; }
.faq summary { list-style: none; cursor: pointer; font-size: clamp(20px, 2.4vw, 36px); display: flex; justify-content: space-between; gap: 20px; letter-spacing: -.02em; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; color: var(--ruby); }
.faq details[open] summary::after { content: "–"; }
.faq p { margin-top: 14px; max-width: 760px; font-size: 17px; line-height: 1.4; color: #333; }

/* ---------- Trang con ---------- */
.phero { position: relative; overflow: hidden; background: var(--ink); color: #fff; padding: 28vh 20px 10vh; }
.phero::before { content: ""; position: absolute; inset: 0; background: radial-gradient(at 12% 100%, rgba(29, 78, 216, .6), transparent 32%), radial-gradient(at 95% 70%, rgba(29, 78, 216, .35), transparent 28%); }
.phero > * { position: relative; }
.phero .tag { margin-bottom: 3vh; opacity: .8; }
.phero .tag a:hover { color: var(--ruby); }
.phero h1 { font-size: clamp(48px, 11vw, 190px); font-weight: 700; letter-spacing: -.05em; line-height: .95; }
.phero .lead { max-width: 640px; margin-top: 4vh; font-size: clamp(18px, 2vw, 28px); line-height: 1.25; opacity: .85; }
.cover { margin: 0; }
.cover img { width: 100%; max-height: 80vh; object-fit: cover; }
.prose { max-width: 820px; }
.prose p { font-size: clamp(18px, 1.7vw, 24px); line-height: 1.45; margin-bottom: 22px; }
.meta-line { display: block; font-size: 12px; text-transform: uppercase; letter-spacing: .08em; color: #777; margin-bottom: 20px; }
.gallery { display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px; margin: 6vh 0; }
.gallery figure { margin: 0; overflow: hidden; }
.gallery img { width: 100%; transition: transform .8s; }
.gallery figure:hover img { transform: scale(1.04); }

/* ---------- CTA nền đỏ ---------- */
.cta { background: var(--ruby); color: #fff; text-align: center; padding: 0 4vw; flex-direction: column; gap: 30px; }
.cta a.t { font-size: clamp(34px, 7vw, 120px); font-weight: 500; line-height: 1; letter-spacing: -.05em; max-width: 1300px; }
.cta a.t:hover { color: #000; }
.cta .row { display: flex; gap: 12px; flex-wrap: wrap; justify-content: center; }
.cta .row a { background: #fff; color: var(--ruby); border-radius: 99px; padding: 12px 22px; font-size: 14px; }
.cta .row a:hover { background: #000; color: #fff; }

/* ---------- Footer ---------- */
.adx-f { background: #000; color: #fff; padding: 60px 20px; display: grid; grid-template-columns: repeat(4, 1fr); gap: 40px 24px; }
.adx-f h4 { font-size: 11px; text-transform: uppercase; letter-spacing: .08em; color: #888; margin-bottom: 16px; font-weight: 500; }
.adx-f li { font-size: 14px; line-height: 1.4; margin-bottom: 8px; color: #ddd; }
.adx-f a:hover { color: var(--ruby); }
.bigmark { grid-column: 1 / -1; margin-top: 40px; }
.bigmark img { width: min(30vw, 260px); height: auto; border-radius: 18px; opacity: .95; }
.copy { grid-column: 1 / -1; color: #777; font-size: 11px; }

/* ---------- Biểu tượng mạng xã hội ---------- */
.socials { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 18px; }
.soc { width: 46px; height: 46px; border-radius: 50%; display: grid; place-items: center; border: 1px solid #555; color: #fff; transition: background .25s, border-color .25s, color .25s; }
.soc:hover { background: var(--ruby); border-color: var(--ruby); color: #fff !important; }
.svc.contact .soc { color: var(--ink); border-color: #111; }
.svc.contact .socials { margin-top: 0; }

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  .adx-h nav { display: none; }
  .burger { display: block; }
  .adx-h { grid-template-columns: 1fr auto; }
  .gallery, .cards, .about, .adx-f { grid-template-columns: 1fr; }
  .stats { grid-template-columns: repeat(2, 1fr) !important; }
  .stats div { padding: 32px 16px; border-right: 0; border-bottom: 1px solid var(--line); }
  .stats div:nth-child(2n+1) { border-right: 1px solid var(--line); }
  .stats div:last-child { grid-column: 1 / -1; border-right: 0; border-bottom: 0; }
  .svc > div, .svc > a { grid-template-columns: 44px 1fr; }
  .svc > div > p, .svc > a > p { grid-column: 2; }
  .svc.plain > div { grid-template-columns: 44px 1fr; }
  .card.wide { aspect-ratio: 16 / 10; }
  .pillar h3, .hero h2 { font-size: clamp(44px, 17vw, 120px); }
  .pillar.img { min-height: 0; height: min(100svh, 640px); }
  .pillar p { left: 16px; right: 16px; max-width: none; bottom: 20px; font-size: 14px; line-height: 1.35; }
  .tag { font-size: 12px; }
  .pill { font-size: 12px; padding: 11px 20px; bottom: 28px; }
  .statement p { font-size: clamp(28px, 8.2vw, 48px); }
  .sec { padding: 10vh 16px; }
  .sec h2 { font-size: clamp(40px, 13vw, 72px); margin-bottom: 5vh; }
  .sec .intro { font-size: 17px; margin-top: -2vh; }
  .svc h4 { font-size: 24px; }
  .svc p { font-size: 15px; }
  .phero { padding: 22vh 16px 8vh; }
  .phero h1 { font-size: clamp(44px, 14vw, 90px); }
  .cta a.t { font-size: clamp(32px, 10vw, 56px); }
  .adx-f { padding: 40px 16px; }
  .adx-f li { font-size: 15px; }
}
@media (max-width: 600px) {
  .mq-i { height: 48px; font-size: 18px; }
  .mq-i img { max-width: 110px; }
  .mq-t { gap: 32px; padding-right: 32px; animation-duration: 30s; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .mq-t { animation: none; }
  .mq { overflow-x: auto; }
}