/* ===== Xây Dựng Nguyễn Khang — Stylesheet ===== */
:root{
  --navy:#132a4a;
  --navy-2:#1b3a63;
  --gold:#f5b301;
  --gold-2:#ffc72c;
  --ink:#0f172a;
  --body:#475569;
  --line:#e6ebf2;
  --bg:#ffffff;
  --bg-alt:#f5f8fc;
  --radius:16px;
  --shadow:0 10px 30px -12px rgba(19,42,74,.18);
  --shadow-lg:0 24px 60px -20px rgba(19,42,74,.28);
  --maxw:1200px;
  --font:'Be Vietnam Pro',-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,Arial,sans-serif;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:84px}
body{font-family:var(--font);color:var(--body);background:var(--bg);line-height:1.65;-webkit-font-smoothing:antialiased;overflow-x:hidden}
img,video{max-width:100%;display:block}
a{color:inherit;text-decoration:none}
.container{width:100%;max-width:var(--maxw);margin:0 auto;padding:0 20px}

/* ===== Buttons ===== */
.btn{display:inline-flex;align-items:center;gap:8px;padding:12px 22px;border-radius:999px;font-weight:600;font-size:15px;border:2px solid transparent;cursor:pointer;transition:.25s;white-space:nowrap}
.btn--primary{background:var(--gold);color:var(--navy)}
.btn--primary:hover{background:var(--gold-2);transform:translateY(-2px);box-shadow:0 12px 24px -8px rgba(245,179,1,.5)}
.btn--ghost{background:transparent;color:#fff;border-color:rgba(255,255,255,.4)}
.btn--ghost:hover{background:rgba(255,255,255,.12);border-color:#fff}
.btn--lg{padding:16px 32px;font-size:17px}
.btn--phone{background:var(--navy);color:#fff}
.btn--phone:hover{background:var(--navy-2)}

/* ===== Header ===== */
.header{position:fixed;top:0;left:0;right:0;z-index:100;background:rgba(255,255,255,.92);backdrop-filter:blur(12px);border-bottom:1px solid transparent;transition:.3s}
.header.is-scrolled{box-shadow:0 4px 20px -8px rgba(19,42,74,.15);border-bottom-color:var(--line)}
.header__inner{display:flex;align-items:center;gap:24px;height:72px}
.logo{display:flex;align-items:center;gap:12px;margin-right:auto}
.logo__mark{display:grid;place-items:center;width:44px;height:44px;border-radius:12px;background:var(--navy);color:var(--gold);font-weight:800;font-size:18px;letter-spacing:.5px}
.logo__text{display:flex;flex-direction:column;line-height:1.1}
.logo__text strong{font-size:11px;letter-spacing:2px;color:var(--body);font-weight:600}
.logo__text em{font-style:normal;font-size:17px;font-weight:800;color:var(--navy);letter-spacing:.3px}
.nav{display:flex;gap:28px}
.nav a{font-weight:500;font-size:15px;color:var(--navy);position:relative;padding:4px 0}
.nav a::after{content:'';position:absolute;left:0;bottom:0;width:0;height:2px;background:var(--gold);transition:.25s}
.nav a:hover::after{width:100%}
.nav-toggle{display:none;flex-direction:column;gap:5px;background:none;border:0;cursor:pointer;padding:8px}
.nav-toggle span{width:24px;height:2.5px;background:var(--navy);border-radius:2px;transition:.3s}

/* ===== Hero ===== */
.hero{position:relative;min-height:100vh;display:flex;align-items:center;padding:120px 0 80px;overflow:hidden}
.hero__bg{position:absolute;inset:0;background:linear-gradient(120deg,rgba(19,42,74,.97) 0%,rgba(19,42,74,.9) 45%,rgba(27,58,99,.72) 100%),url('../img/phapvan-3d-15.jpg') center/cover;z-index:-1}
.hero__bg::after{content:'';position:absolute;inset:0;background:radial-gradient(circle at 80% 20%,rgba(245,179,1,.18),transparent 55%)}
.hero__inner{position:relative}
.hero__content{max-width:680px}
.hero__eyebrow{display:inline-block;font-family:Georgia,serif;font-style:italic;font-size:22px;color:var(--gold-2);margin-bottom:8px}
.hero__title{font-size:clamp(32px,5vw,56px);line-height:1.15;color:#fff;font-weight:800;letter-spacing:-.5px}
.hero__title span{color:var(--gold)}
.hero__sub{color:rgba(255,255,255,.82);font-size:18px;margin:18px 0 30px}
.hero__actions{display:flex;gap:14px;flex-wrap:wrap}
.hero__stats{display:flex;gap:40px;list-style:none;margin-top:48px;padding-top:32px;border-top:1px solid rgba(255,255,255,.16);flex-wrap:wrap}
.hero__stats strong{display:block;font-size:34px;font-weight:800;color:var(--gold)}
.hero__stats span{font-size:14px;color:rgba(255,255,255,.75)}

/* ===== Section ===== */
.section{padding:88px 0}
.section--alt{background:var(--bg-alt)}
.section__head{text-align:center;max-width:680px;margin:0 auto 52px}
.section__eyebrow{color:var(--gold);font-weight:700;font-size:14px;letter-spacing:1.5px;text-transform:uppercase;margin-bottom:10px}
.section__title{font-size:clamp(26px,3.5vw,38px);color:var(--navy);font-weight:800;line-height:1.25}
.section__desc{margin-top:14px;font-size:16px}

/* ===== Services ===== */
.services{display:grid;grid-template-columns:repeat(3,1fr);gap:26px}
.service-card{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:34px 28px;transition:.3s}
.service-card:hover{transform:translateY(-6px);box-shadow:var(--shadow-lg);border-color:transparent}
.service-card--featured{background:var(--navy);border-color:var(--navy)}
.service-card--featured h3,.service-card--featured p{color:#fff}
.service-card--featured p{color:rgba(255,255,255,.78)}
.service-card--featured .service-card__list li{color:rgba(255,255,255,.9)}
.service-card__icon{width:64px;height:64px;border-radius:16px;background:rgba(245,179,1,.14);color:var(--gold);display:grid;place-items:center;margin-bottom:20px}
.service-card--featured .service-card__icon{background:rgba(245,179,1,.2)}
.service-card h3{font-size:21px;color:var(--navy);margin-bottom:10px}
.service-card p{font-size:15px;margin-bottom:16px}
.service-card__list{list-style:none;display:flex;flex-direction:column;gap:8px}
.service-card__list li{position:relative;padding-left:22px;font-size:14.5px;color:var(--body)}
.service-card__list li::before{content:'✓';position:absolute;left:0;color:var(--gold);font-weight:700}

/* ===== Projects ===== */
.project{background:#fff;border:1px solid var(--line);border-radius:20px;padding:32px;margin-bottom:40px}
.project__head{margin-bottom:22px}
.project__status{display:inline-block;font-size:13px;font-weight:700;padding:5px 14px;border-radius:999px;margin-bottom:12px}
.project__status--done{background:rgba(34,197,94,.12);color:#16a34a}
.project__status--doing{background:rgba(245,179,1,.16);color:#b8860b}
.project__title{font-size:26px;color:var(--navy);font-weight:800}
.project__meta{font-size:15px;margin-top:4px}
.project__tabs{display:flex;gap:10px;flex-wrap:wrap;margin-bottom:24px;border-bottom:1px solid var(--line);padding-bottom:16px}
.tab{padding:9px 20px;border-radius:999px;border:1.5px solid var(--line);background:#fff;font-family:inherit;font-size:14.5px;font-weight:600;color:var(--body);cursor:pointer;transition:.2s}
.tab:hover{border-color:var(--gold);color:var(--navy)}
.tab.is-active{background:var(--navy);border-color:var(--navy);color:#fff}

/* Gallery */
.gallery{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:14px}
.gallery.is-hidden{display:none}
.gallery__item{position:relative;border-radius:12px;overflow:hidden;aspect-ratio:4/3;cursor:zoom-in;background:var(--bg-alt)}
.gallery__item img{width:100%;height:100%;object-fit:cover;transition:.5s}
.gallery__item:hover img{transform:scale(1.06)}
.gallery__item::after{content:'⤢';position:absolute;right:10px;bottom:10px;width:34px;height:34px;border-radius:50%;background:rgba(19,42,74,.7);color:#fff;display:grid;place-items:center;opacity:0;transition:.3s;font-size:16px}
.gallery__item:hover::after{opacity:1}

/* Video grid */
.video-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:20px}
.video-grid.is-hidden{display:none}
.video-item{background:var(--bg-alt);border-radius:14px;overflow:hidden;border:1px solid var(--line)}
.video-item video{width:100%;aspect-ratio:16/9;object-fit:cover;background:#000}
.video-item figcaption{padding:12px 16px;font-size:14px;font-weight:600;color:var(--navy)}

/* ===== Steps ===== */
.steps{list-style:none;display:grid;grid-template-columns:repeat(4,1fr);gap:24px;counter-reset:s}
.step{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:30px 24px;position:relative;transition:.3s}
.step:hover{box-shadow:var(--shadow);transform:translateY(-4px)}
.step__num{font-size:40px;font-weight:800;color:var(--gold);opacity:.35;line-height:1;display:block;margin-bottom:12px}
.step h3{font-size:18px;color:var(--navy);margin-bottom:8px}
.step p{font-size:14.5px}

/* ===== Reasons ===== */
.reasons{display:grid;grid-template-columns:repeat(4,1fr);gap:22px}
.reason{background:#fff;border-radius:var(--radius);padding:28px 24px;border:1px solid var(--line);transition:.3s}
.reason:hover{transform:translateY(-4px);box-shadow:var(--shadow)}
.reason__icon{width:46px;height:46px;border-radius:50%;background:var(--gold);color:var(--navy);display:grid;place-items:center;font-weight:800;font-size:22px;margin-bottom:16px}
.reason h3{font-size:18px;color:var(--navy);margin-bottom:8px}
.reason p{font-size:14.5px}

/* ===== CTA ===== */
.cta{background:linear-gradient(120deg,var(--navy) 0%,var(--navy-2) 100%);padding:56px 0}
.cta__inner{display:flex;align-items:center;justify-content:space-between;gap:30px;flex-wrap:wrap}
.cta__text h2{color:#fff;font-size:clamp(22px,3vw,30px);font-weight:800}
.cta__text p{color:rgba(255,255,255,.8);margin-top:6px}

/* ===== Contact ===== */
.contact{display:grid;grid-template-columns:1fr 1.4fr;gap:30px;align-items:stretch}
.contact__info{display:flex;flex-direction:column;gap:16px}
.contact__row{display:flex;gap:16px;align-items:center;background:#fff;border:1px solid var(--line);border-radius:14px;padding:18px 20px;transition:.25s}
.contact__row:hover{border-color:var(--gold);box-shadow:var(--shadow)}
.contact__ic{width:48px;height:48px;border-radius:12px;background:rgba(245,179,1,.14);display:grid;place-items:center;font-size:22px;flex-shrink:0}
.contact__row strong{color:var(--navy);font-size:14px}
.contact__row span{font-size:15px}
.contact__map{border-radius:14px;overflow:hidden;border:1px solid var(--line);min-height:340px}
.contact__map iframe{width:100%;height:100%;min-height:340px;border:0}

/* ===== Footer ===== */
.footer{background:var(--navy);color:rgba(255,255,255,.8);padding:48px 0 28px}
.footer__inner{display:flex;flex-direction:column;gap:22px;align-items:center;text-align:center}
.footer__brand{display:flex;align-items:center;gap:14px;text-align:left}
.footer__brand strong{color:#fff;font-size:16px;letter-spacing:.5px}
.footer__brand p{font-size:13px;color:rgba(255,255,255,.6)}
.footer__links{display:flex;gap:24px;flex-wrap:wrap;justify-content:center}
.footer__links a{font-size:14.5px;transition:.2s}
.footer__links a:hover{color:var(--gold)}
.footer__copy{font-size:13px;color:rgba(255,255,255,.5);border-top:1px solid rgba(255,255,255,.1);padding-top:20px;width:100%}

/* ===== FAB ===== */
.fab{position:fixed;right:20px;bottom:20px;width:58px;height:58px;border-radius:50%;background:var(--gold);color:var(--navy);display:none;place-items:center;z-index:90;box-shadow:0 10px 24px -6px rgba(245,179,1,.6);animation:pulse 2s infinite}
@keyframes pulse{0%,100%{box-shadow:0 10px 24px -6px rgba(245,179,1,.6)}50%{box-shadow:0 10px 34px 2px rgba(245,179,1,.5)}}

/* ===== Lightbox ===== */
.lightbox{position:fixed;inset:0;background:rgba(8,15,30,.94);z-index:200;display:flex;align-items:center;justify-content:center;padding:20px}
.lightbox[hidden]{display:none}
.lightbox__img{max-width:92vw;max-height:88vh;border-radius:8px;box-shadow:var(--shadow-lg)}
.lightbox__close,.lightbox__prev,.lightbox__next{position:absolute;background:rgba(255,255,255,.12);color:#fff;border:0;border-radius:50%;cursor:pointer;display:grid;place-items:center;transition:.2s}
.lightbox__close:hover,.lightbox__prev:hover,.lightbox__next:hover{background:rgba(255,255,255,.25)}
.lightbox__close{top:20px;right:20px;width:46px;height:46px;font-size:28px;line-height:1}
.lightbox__prev,.lightbox__next{top:50%;transform:translateY(-50%);width:52px;height:52px;font-size:32px;line-height:1}
.lightbox__prev{left:20px}.lightbox__next{right:20px}

/* ===== Reveal on scroll ===== */
.reveal{opacity:0;transform:translateY(24px);transition:opacity .6s ease,transform .6s ease}
.reveal.is-visible{opacity:1;transform:translateY(0)}
@media(prefers-reduced-motion:reduce){.reveal{opacity:1;transform:none;transition:none}}

/* ===== Responsive ===== */
@media(max-width:960px){
  .services,.reasons{grid-template-columns:repeat(2,1fr)}
  .steps{grid-template-columns:repeat(2,1fr)}
  .contact{grid-template-columns:1fr}
  .header__cta{display:none}
}
@media(max-width:720px){
  .nav{position:fixed;top:72px;left:0;right:0;background:#fff;flex-direction:column;gap:0;padding:12px 20px 20px;border-bottom:1px solid var(--line);box-shadow:var(--shadow);transform:translateY(-140%);transition:.35s;visibility:hidden}
  .nav.is-open{transform:translateY(0);visibility:visible}
  .nav a{padding:14px 0;border-bottom:1px solid var(--line)}
  .nav-toggle{display:flex}
  .header__cta{display:inline-flex;padding:10px 16px;font-size:14px}
  .logo__text em{font-size:15px}
  .services,.reasons,.steps{grid-template-columns:1fr}
  .hero{min-height:auto;padding:110px 0 60px}
  .hero__stats{gap:24px}
  .hero__stats strong{font-size:26px}
  .section{padding:60px 0}
  .project{padding:20px}
  .gallery{grid-template-columns:repeat(2,1fr);gap:10px}
  .video-grid{grid-template-columns:1fr}
  .fab{display:grid}
  .cta__inner{flex-direction:column;text-align:center}
}
@media(max-width:420px){
  .hero__title{font-size:28px}
  .gallery{grid-template-columns:1fr 1fr}
}