/* ==========================================================================
   header.css - Thanh điều hướng chính
   Nền chạy full viewport, nội dung nằm trong .container.
   ========================================================================== */

.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background-color: #fff;
  border-bottom: 1px solid var(--color-border-soft);
}

.site-header__inner {
  display: flex;
  align-items: center;
  gap: var(--space-6);
  height: var(--header-height);
}

/* ---------------------------------------------------------------- Logo */
.site-logo {
  flex: none;
  display: inline-flex;
  align-items: center;
}

.site-logo img {
  height: 40px;
  width: auto;
}

/* ---------------------------------------------------------- Điều hướng */
.site-nav {
  flex: 1;
  display: flex;
  justify-content: center;
}

.site-nav__list {
  display: flex;
  align-items: center;
  gap: 30px;
}

.site-nav__link {
  position: relative;
  display: inline-block;
  padding: 6px 0;
  font-size: 13.5px;
  font-weight: 500;
  color: var(--color-navy);
  white-space: nowrap;
}

.site-nav__link::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  border-radius: 2px;
  background-color: var(--color-gold);
  opacity: 0;
  transform: scaleX(0.4);
  transition: opacity var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.site-nav__link:hover {
  color: var(--color-accent);
}

.site-nav__link[aria-current="page"] {
  font-weight: 600;
  color: var(--color-navy);
}

.site-nav__link[aria-current="page"]::after,
.site-nav__link:hover::after {
  opacity: 1;
  transform: scaleX(1);
}

/* ------------------------------------------------------------ Hành động */
.site-header__actions {
  flex: none;
  display: flex;
  align-items: center;
  gap: 18px;
}

.header-youtube {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 24px;
  transition: transform var(--dur) var(--ease);
}

.header-youtube:hover {
  transform: scale(1.06);
}

.site-header__actions .btn {
  min-height: 42px;
  padding: 0 22px;
  font-size: var(--fs-sm);
}

/* -------------------------------------------------------- Nút mobile */
.nav-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  margin-left: auto;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  color: var(--color-navy);
}

.nav-toggle__bar,
.nav-toggle__bar::before,
.nav-toggle__bar::after {
  display: block;
  width: 20px;
  height: 2px;
  border-radius: 2px;
  background-color: currentColor;
  transition: transform var(--dur) var(--ease), opacity var(--dur) var(--ease);
}

.nav-toggle__bar {
  position: relative;
}

.nav-toggle__bar::before,
.nav-toggle__bar::after {
  content: "";
  position: absolute;
  left: 0;
}

.nav-toggle__bar::before { top: -6px; }
.nav-toggle__bar::after { top: 6px; }

.nav-toggle[aria-expanded="true"] .nav-toggle__bar {
  background-color: transparent;
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar::before {
  transform: translateY(6px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar::after {
  transform: translateY(-6px) rotate(-45deg);
}