.site_header {
  position: fixed;
  top: 24px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 1000;

  width: min(88%, 1480px);
  min-height: 84px;
  padding: 10px 28px;

  display: grid;
  grid-template-columns: 170px 1fr;
  align-items: center;

  border-radius: 28px;
  background: rgba(255, 255, 255, 0.82);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);

  border: 1px solid rgba(255, 255, 255, 0.65);
  box-shadow: 0 18px 50px rgba(8, 47, 44, 0.08);
  transition:
    top 0.25s ease,
    width 0.25s ease,
    min-height 0.25s ease,
    padding 0.25s ease,
    background 0.25s ease,
    box-shadow 0.25s ease;
}

.site_header.scrolled {
  top: 12px;
  width: min(84%, 1380px);
  min-height: 68px;
  padding: 7px 24px;
  background: rgba(255, 255, 255, 0.92);
  box-shadow: 0 14px 38px rgba(8, 47, 44, 0.12);
}

.site_header.scrolled .brand_logo {
  width: 70px;
}

.site_header.scrolled .main_nav {
  gap: 28px;
}

.brand {
  display: flex;
  align-items: center;
  justify-content: flex-start;
  text-decoration: none;
}

.brand_logo {
  width: 86px;
  height: auto;
  display: block;
  transition: width 0.25s ease;
}

.brand_mark,
.brand_text {
  display: none;
}

.main_nav {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: clamp(18px, 2vw, 34px);
}

.main_nav a {
  position: relative;
  color: var(--rivtara-mountain);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 800;
  white-space: nowrap;
  transition: color 0.25s ease;
}

.main_nav a::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: -8px;
  width: 0;
  height: 3px;
  background: var(--rivtara-blue);
  border-radius: 999px;
  transform: translateX(-50%);
  transition: width 0.3s ease;
}

.main_nav a:hover,
.main_nav a.active {
  color: var(--rivtara-blue);
}

.main_nav a:hover::after,
.main_nav a.active::after {
  width: 72%;
}

.login_link {
  display: none;
}

.main_nav .nav_cta {
  background: linear-gradient(135deg, var(--rivtara-blue), var(--rivtara-river));
  color: #fff;
  padding: 13px 24px;
  border-radius: 999px;
  box-shadow: 0 12px 25px rgba(11, 110, 142, 0.25);
  white-space: nowrap;
}

.main_nav .nav_cta::after {
  display: none;
}

.main_nav .nav_cta:hover {
  color: #fff;
  transform: translateY(-2px);
  box-shadow: 0 16px 35px rgba(11, 110, 142, 0.35);
}

.menu_toggle {
  display: none;
  border: 0;
  background: transparent;
}

.menu_toggle span {
  display: block;
  width: 26px;
  height: 2px;
  background: var(--rivtara-mountain);
  margin: 5px 0;
}

@media (max-width: 1400px) {
  .site_header {
    width: min(calc(100% - 72px), 1280px);
    grid-template-columns: 140px 1fr;
  }

  .main_nav {
    gap: 18px;
  }

  .main_nav a {
    font-size: 0.86rem;
  }

  .main_nav .nav_cta {
    padding: 12px 19px;
  }
}

@media (max-width: 1280px) {
  .site_header {
    width: min(calc(100% - 48px), 1320px);
    grid-template-columns: 135px 1fr;
    padding: 9px 22px;
  }

  .brand_logo {
    width: 74px;
  }

  .main_nav {
    gap: 18px;
  }

  .main_nav a {
    font-size: 0.86rem;
  }

  .main_nav .nav_cta {
    padding: 12px 18px;
  }
}

@media (max-width: 1080px) {
  .site_header {
    width: calc(100% - 28px);
    grid-template-columns: auto auto;
  }

  .menu_toggle {
    display: block;
    justify-self: end;
  }

  .main_nav {
    position: absolute;
    top: 92px;
    left: 0;
    right: 0;
    display: none;
    flex-direction: column;
    gap: 18px;
    padding: 24px;
    border-radius: 24px;
    background: #fff;
    box-shadow: 0 18px 50px rgba(8, 47, 44, 0.08);
  }

  .main_nav.open {
    display: flex;
  }
}