.se-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  width: 100%;
  backdrop-filter: blur(16px);
  background: linear-gradient(90deg, rgba(4, 18, 38, 0.95), rgba(9, 30, 66, 0.9));
  border-bottom: 1px solid rgba(120, 144, 180, 0.35);
}

.se-header__inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0.75rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
}

.se-header__brand {
  display: flex;
  align-items: center;
}

.se-header__logo {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  color: #f9fbff;
  text-decoration: none;
}

.se-header__logo-mark {
  width: 1.9rem;
  height: 1.9rem;
  border-radius: 0.9rem;
  background: radial-gradient(circle at 30% 20%, #4fd1c5, #1a73e8 55%, #020817 100%);
  box-shadow: 0 0 0 1px rgba(144, 202, 249, 0.4), 0 12px 25px rgba(2, 8, 23, 0.9);
}

.se-header__logo-text {
  font-family: "Space Grotesk", system-ui, -apple-system, BlinkMacSystemFont, "Inter", sans-serif;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  font-size: 0.95rem;
  white-space: nowrap;
}

.se-header__nav {
  flex: 1 1 auto;
}

.se-header__nav-list {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1.75rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.se-header__nav-link {
  position: relative;
  font-family: "Inter", system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
  font-size: 0.95rem;
  color: #d7e3ff;
  text-decoration: none;
  padding: 0.35rem 0;
}

.se-header__nav-link::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 0;
  height: 2px;
  border-radius: 999px;
  background: linear-gradient(90deg, #4fd1c5, #1a73e8);
  transition: width 0.18s ease-out;
}

.se-header__nav-link:hover::after,
.se-header__nav-link:focus-visible::after {
  width: 100%;
}

.se-header__nav-link:focus-visible {
  outline: 2px solid #4fd1c5;
  outline-offset: 4px;
  border-radius: 3px;
}

.se-header__actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.se-header__cart-link {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.3rem 0.7rem;
  border-radius: 999px;
  border: 1px solid rgba(129, 178, 255, 0.5);
  background: radial-gradient(circle at 0 0, rgba(79, 209, 197, 0.25), transparent 45%), rgba(10, 25, 47, 0.95);
  color: #e3f2ff;
  text-decoration: none;
  font-size: 0.9rem;
}

.se-header__cart-link:hover,
.se-header__cart-link:focus-visible {
  border-color: #4fd1c5;
  box-shadow: 0 0 0 1px rgba(79, 209, 197, 0.3);
}

.se-header__cart-link:focus-visible {
  outline: 2px solid #4fd1c5;
  outline-offset: 3px;
}

.se-header__cart-icon {
  font-size: 1rem;
}

.se-header__cart-count {
  min-width: 1.25rem;
  height: 1.25rem;
  border-radius: 999px;
  background: #1a73e8;
  color: #f9fbff;
  font-size: 0.7rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0 0.15rem;
}

/* Mobile toggle */
.se-header__toggle {
  display: none;
  position: relative;
  width: 2.25rem;
  height: 2.25rem;
  border-radius: 999px;
  border: 1px solid rgba(144, 202, 249, 0.6);
  background: rgba(3, 16, 37, 0.95);
  padding: 0;
  cursor: pointer;
}

.se-header__toggle:focus-visible {
  outline: 2px solid #4fd1c5;
  outline-offset: 3px;
}

.se-header__toggle-bar {
  position: absolute;
  left: 22%;
  right: 22%;
  height: 2px;
  border-radius: 999px;
  background: #e3f2ff;
  transition: transform 0.16s ease-out, opacity 0.16s ease-out, top 0.16s ease-out, bottom 0.16s ease-out;
}

.se-header__toggle-bar:nth-child(1) {
  top: 30%;
}

.se-header__toggle-bar:nth-child(2) {
  top: 50%;
  transform: translateY(-50%);
}

.se-header__toggle-bar:nth-child(3) {
  bottom: 30%;
}

.se-header__toggle[aria-expanded="true"] .se-header__toggle-bar:nth-child(1) {
  top: 50%;
  transform: translateY(-50%) rotate(45deg);
}

.se-header__toggle[aria-expanded="true"] .se-header__toggle-bar:nth-child(2) {
  opacity: 0;
}

.se-header__toggle[aria-expanded="true"] .se-header__toggle-bar:nth-child(3) {
  bottom: auto;
  top: 50%;
  transform: translateY(-50%) rotate(-45deg);
}

/* Responsive layout */
@media (max-width: 768px) {
  .se-header__inner {
    padding-inline: 1rem;
  }

  .se-header__toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
  }

  .se-header__nav {
    position: absolute;
    inset-inline: 0;
    top: 100%;
    background: radial-gradient(circle at 0 0, rgba(79, 209, 197, 0.12), transparent 60%), rgba(4, 18, 38, 0.98);
    border-bottom: 1px solid rgba(120, 144, 180, 0.4);
    transform-origin: top;
    transform: scaleY(0.9);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition: opacity 0.16s ease-out, transform 0.16s ease-out, visibility 0.16s;
  }

  .se-header__nav-list {
    flex-direction: column;
    align-items: flex-start;
    padding: 0.5rem 1.25rem 1rem;
    gap: 0.4rem;
  }

  .se-header__nav-link {
    width: 100%;
    padding-block: 0.4rem;
  }

  .se-header__nav-link::after {
    display: none;
  }

  .se-header__nav-link:hover,
  .se-header__nav-link:focus-visible {
    background: rgba(15, 76, 129, 0.7);
    border-radius: 0.4rem;
  }

  .se-header__actions {
    margin-left: auto;
  }

  .se-header__nav--open {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: scaleY(1);
  }
}

@media (max-width: 520px) {
  .se-header__inner {
    gap: 0.75rem;
  }

  .se-header__logo-text {
    font-size: 0.88rem;
  }

  .se-header__cart-text {
    display: none;
  }

  .se-header__cart-link {
    padding-inline: 0.6rem;
  }
}