/* ============================================================
   global.css — HTS Engineering v3
   Navigation, Header, Footer, Float buttons, Skip link
   ============================================================ */

/* ── SKIP LINK ───────────────────────────────────────────── */
.skip-link {
  position: absolute;
  top: -100%;
  left: 1rem;
  padding: .75rem 1.5rem;
  background: var(--clr-primary);
  color: #fff;
  border-radius: 0 0 var(--radius-sm) var(--radius-sm);
  font-weight: 700;
  z-index: 9999;
  transition: top .2s ease;
}
.skip-link:focus { top: 0 }

/* ── SITE HEADER ─────────────────────────────────────────── */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  padding: .75rem 0;
  background: rgba(7,16,29,.0);
  transition: background .3s ease, box-shadow .3s ease, padding .3s ease;
}
.site-header.is-scrolled {
  background: rgba(7,16,29,.92);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  box-shadow: 0 4px 24px rgba(0,0,0,.2);
  padding: .5rem 0;
}
.site-nav {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  background: rgba(7,16,29,.55);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border: 1px solid rgba(255,255,255,.1);
  border-radius: 20px;
  padding: .875rem 1.25rem;
  box-shadow: 0 12px 30px rgba(0,0,0,.12);
}

/* Logo */
.site-nav__logo {
  display: flex;
  align-items: baseline;
  gap: .375rem;
  text-decoration: none;
  flex-shrink: 0;
}
.site-nav__logo-hts {
  font-family: var(--font-display);
  font-size: 1.375rem;
  font-weight: 700;
  color: var(--clr-accent);
  letter-spacing: .03em;
}
.site-nav__logo-eng {
  font-size: 1.125rem;
  font-weight: 700;
  color: #fff;
  letter-spacing: .02em;
}
.site-nav__logo-tag {
  font-size: .625rem;
  font-weight: 700;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: rgba(255,255,255,.4);
  align-self: center;
}

/* Links */
.site-nav__links {
  display: flex;
  align-items: center;
  gap: .25rem;
  flex: 1;
  justify-content: center;
}
.site-nav__item {
  padding: .45rem .875rem;
  border-radius: 10px;
  font-size: .875rem;
  font-weight: 600;
  color: rgba(255,255,255,.72);
  transition: background .2s ease, color .2s ease;
  white-space: nowrap;
}
.site-nav__item:hover,
.site-nav__item.is-active {
  background: rgba(255,255,255,.1);
  color: #fff;
}
.site-nav__item.is-active { color: var(--clr-accent) }

/* CTA */
.site-nav__cta {
  min-height: 42px;
  padding: 0 1.25rem;
  font-size: .875rem;
  border-radius: 12px;
  flex-shrink: 0;
}

/* Burger */
.site-nav__burger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 38px;
  height: 38px;
  padding: .5rem;
  background: none;
  border: none;
  cursor: pointer;
  flex-shrink: 0;
}
.site-nav__burger span {
  display: block;
  width: 100%;
  height: 2px;
  background: rgba(255,255,255,.8);
  border-radius: 2px;
  transition: transform .3s ease, opacity .3s ease;
}
.site-nav__burger[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg) }
.site-nav__burger[aria-expanded="true"] span:nth-child(2) { opacity: 0 }
.site-nav__burger[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg) }

/* ── FLOAT BUTTONS ───────────────────────────────────────── */
.float-actions {
  position: fixed;
  right: 1.25rem;
  bottom: 1.5rem;
  z-index: 90;
  display: flex;
  flex-direction: column;
  gap: .625rem;
}
.float-btn {
  width: 52px;
  height: 52px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-lg);
  transition: transform .2s ease, box-shadow .2s ease;
  color: #fff;
}
.float-btn:hover { transform: scale(1.1); box-shadow: var(--shadow-xl) }
.float-btn--phone { background: linear-gradient(135deg, var(--clr-primary), var(--clr-primary-2)) }
.float-btn--zalo  { background: linear-gradient(135deg, #0068ff, #0050cc) }

/* ── FOOTER ──────────────────────────────────────────────── */
.site-footer {
  background: var(--clr-bg);
  color: rgba(255,255,255,.65);
  padding-top: var(--sp-3xl);
  padding-bottom: var(--sp-xl);
  border-top: 1px solid rgba(255,255,255,.06);
}
.footer-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1fr;
  gap: 2rem;
  padding-bottom: var(--sp-2xl);
  border-bottom: 1px solid rgba(255,255,255,.08);
}
.footer-brand__logo { margin-bottom: var(--sp-md) }
.footer-brand__desc {
  font-size: .875rem;
  line-height: 1.75;
  color: rgba(255,255,255,.5);
  margin-bottom: var(--sp-lg);
}
.footer-contact-item {
  display: flex;
  align-items: flex-start;
  gap: .625rem;
  font-size: .875rem;
  color: rgba(255,255,255,.55);
  margin-bottom: .625rem;
}
.footer-contact-item a { color: rgba(255,255,255,.8); transition: color .2s ease }
.footer-contact-item a:hover { color: var(--clr-accent) }
.footer-col h4 {
  font-size: .6875rem;
  font-weight: 800;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: rgba(255,255,255,.35);
  margin-bottom: var(--sp-md);
}
.footer-links { list-style: none; padding: 0 }
.footer-links li { margin-bottom: .5rem }
.footer-links a {
  font-size: .875rem;
  color: rgba(255,255,255,.55);
  transition: color .2s ease;
}
.footer-links a:hover { color: var(--clr-accent) }
.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding-top: var(--sp-lg);
  flex-wrap: wrap;
}
.footer-bottom p { font-size: .8125rem; color: rgba(255,255,255,.35) }
.footer-social { display: flex; gap: .625rem }
.footer-social a {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(255,255,255,.06);
  border: 1px solid rgba(255,255,255,.1);
  color: rgba(255,255,255,.5);
  font-size: .875rem;
  transition: background .2s ease, color .2s ease;
}
.footer-social a:hover { background: rgba(255,255,255,.12); color: #fff }

/* ── BREADCRUMB ──────────────────────────────────────────── */
.breadcrumb {
  padding: .875rem 0;
  border-bottom: 1px solid rgba(255,255,255,.08);
  margin-bottom: var(--sp-xl);
}
.breadcrumb nav {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: .3rem;
}
.breadcrumb a { font-size: .8125rem; color: rgba(255,255,255,.45); transition: color .2s }
.breadcrumb a:hover { color: var(--clr-accent) }
.breadcrumb .sep { color: rgba(255,255,255,.2); font-size: .75rem; margin-inline: .1rem }
.breadcrumb [aria-current="page"] { font-size: .8125rem; color: rgba(255,255,255,.7) }

/* ── RESPONSIVE NAV ──────────────────────────────────────── */
@media (max-width: 960px) {
  .site-nav__links {
    display: none;
    position: absolute;
    top: calc(100% + .75rem);
    left: 1rem;
    right: 1rem;
    flex-direction: column;
    align-items: stretch;
    background: rgba(7,16,29,.97);
    border: 1px solid rgba(255,255,255,.1);
    border-radius: 16px;
    padding: 1rem;
    gap: .25rem;
    box-shadow: var(--shadow-xl);
  }
  .site-nav__links.is-open { display: flex }
  .site-nav__item { padding: .75rem 1rem }
  .site-nav__burger { display: flex }
  .site-header { position: relative }
  .site-nav { position: relative }
}

@media (max-width: 640px) {
  .footer-grid { grid-template-columns: 1fr 1fr }
  .footer-grid > .footer-brand { grid-column: 1 / -1 }
  .footer-bottom { flex-direction: column; text-align: center }
}
@media (max-width: 400px) {
  .footer-grid { grid-template-columns: 1fr }
}