.site-header {
  position: sticky;
  top: 0;
  z-index: 70;
  background: rgba(255, 255, 255, .92);
  backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid rgba(226, 232, 240, 0.9);
  box-shadow: 0 10px 28px rgba(15, 23, 42, 0.08);
  transition: background .25s ease, box-shadow .25s ease, border-color .25s ease;
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
  position: relative;
}

.logo {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  letter-spacing: .2px;
  text-decoration: none;
  color: inherit;
}

.logo img {
  height: 32px;
  width: auto;
  display: block;
}

.nav a {
  margin-left: 16px;
  text-decoration: none;
  color: inherit;
}

.nav a.active {
  color: var(--primary);
  font-weight: 700;
}

.nav a.btn {
  display: inline-block;
  padding: 10px 16px;
  border-radius: 10px;
  border: 1px solid var(--line);
  text-decoration: none;
  cursor: pointer;
  background: #fff;
  color: var(--fg);
  box-shadow: 0 2px 10px rgba(2, 6, 23, 0.06);
  transition: transform .15s ease, box-shadow .2s ease, filter .2s ease, border-color .2s ease, background .2s ease;
}

.nav a.btn:hover {
  border-color: var(--primary-25);
  background: #fafbfc;
  transform: translateY(-1px);
  box-shadow: 0 4px 14px rgba(2, 6, 23, 0.10);
}

.nav-handle {
  display: none;
}

.menu-toggle {
  display: none;
  background: transparent;
  border: 0;
  padding: 8px;
  margin-left: 8px;
  cursor: pointer;
}

.menu-toggle .bar {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--fg);
  margin: 4px 0;
  transition: transform .2s ease, opacity .2s ease;
}

body.nav-open {
  overflow: hidden;
}

.nav-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.35);
  backdrop-filter: blur(4px);
  opacity: 0;
  pointer-events: none;
  transition: opacity .2s ease;
  z-index: 60;
}

.nav-backdrop.open {
  opacity: 1;
  pointer-events: all;
}

@media (max-width:899px) {
  .site-header .container {
    height: 56px;
  }

  .menu-toggle {
    display: inline-block;
    padding: 10px;
    border-radius: 10px;
    transition: background .2s ease;
  }

  .menu-toggle:active {
    background: rgba(152, 40, 72, 0.08);
  }

  .menu-toggle.open .bar:nth-child(1) {
    transform: translateY(6px) rotate(45deg);
  }

  .menu-toggle.open .bar:nth-child(2) {
    opacity: 0;
  }

  .menu-toggle.open .bar:nth-child(3) {
    transform: translateY(-6px) rotate(-45deg);
  }

  .nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    display: grid;
    grid-template-columns: 1fr;
    gap: 8px;
    transform: translateY(-12px);
    opacity: 0;
    pointer-events: none;
    background: #fff;
    border-bottom: 1px solid var(--line);
    box-shadow: 0 18px 38px rgba(2, 6, 23, 0.16);
    padding: 14px 20px 20px;
    border-radius: 0 0 18px 18px;
    z-index: 80;
    transition: opacity .2s ease, transform .2s ease;
  }

  .nav.open {
    opacity: 1;
    transform: translateY(0);
    pointer-events: auto;
  }

  .nav a {
    margin: 0;
    padding: 10px 6px;
    border-radius: 10px;
    font-weight: 600;
  }

  .nav a:hover {
    background: #f6f7fb;
  }

  .nav a.btn {
    justify-self: stretch;
    width: 100%;
    text-align: center;
  }

  .nav-handle {
    display: block;
    height: 3px;
    width: 40px;
    background: var(--gradient);
    border-radius: 999px;
    margin: 10px auto 0;
    pointer-events: none;
  }
}