/* Header styles for BRAIN PUZZLE WORLD */

.bpw-header {
  position: sticky;
  top: 0;
  z-index: 40;
  backdrop-filter: blur(20px);
  background: linear-gradient(to bottom, rgba(2, 6, 23, 0.96), rgba(2, 6, 23, 0.92));
  border-bottom: 1px solid rgba(15, 23, 42, 0.9);
}

.bpw-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-block: var(--space-3);
  gap: var(--space-4);
}

/* Brand */
.bpw-header__brand {
  display: flex;
  align-items: center;
}

.bpw-header__logo-link {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
}

.bpw-header__logo-mark {
  position: relative;
  width: 2.4rem;
  height: 2.4rem;
  border-radius: 999px;
  background: radial-gradient(circle at 30% 10%, #e0f2fe, #1d4ed8);
  box-shadow: 0 10px 30px rgba(15, 23, 42, 0.8);
  overflow: hidden;
}

.bpw-header__logo-orbit {
  position: absolute;
  inset: 22%;
  border-radius: 999px;
  border: 1px dashed rgba(191, 219, 254, 0.85);
  opacity: 0.75;
}

.bpw-header__logo-node {
  position: absolute;
  width: 0.45rem;
  height: 0.45rem;
  border-radius: 999px;
  background: #fbbf24;
  box-shadow: 0 0 0 3px rgba(250, 204, 21, 0.35);
}

.bpw-header__logo-node--tl {
  top: 0.45rem;
  left: 0.5rem;
}

.bpw-header__logo-node--br {
  right: 0.4rem;
  bottom: 0.5rem;
  background: #22c55e;
  box-shadow: 0 0 0 3px rgba(34, 197, 94, 0.35);
}

.bpw-header__brand-text {
  display: flex;
  flex-direction: column;
}

.bpw-header__brand-name {
  font-size: 0.95rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.bpw-header__brand-tagline {
  font-size: 0.75rem;
  color: var(--color-text-muted);
}

/* Nav */
.bpw-header__nav {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

.bpw-header__nav-list {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  list-style: none;
}

.bpw-header__nav-link {
  position: relative;
  font-size: 0.9rem;
  color: var(--color-text-muted);
  padding-block: 0.25rem;
}

.bpw-header__nav-link::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -0.35rem;
  height: 2px;
  border-radius: 999px;
  background: linear-gradient(90deg, #22c55e, #3b82f6, #22d3ee);
  transform-origin: center;
  transform: scaleX(0);
  transition: transform var(--transition-base);
}

.bpw-header__nav-link:hover::after,
.bpw-header__nav-link:focus-visible::after {
  transform: scaleX(1);
}

.bpw-header__nav-link:hover,
.bpw-header__nav-link:focus-visible {
  color: var(--color-text);
}

.bpw-header__cta {
  display: flex;
  align-items: center;
}

.bpw-header__cta-primary {
  white-space: nowrap;
}

/* Mobile menu toggle */
.bpw-header__menu-toggle {
  display: none;
  align-items: center;
  gap: 0.6rem;
  padding-inline: 0.8rem;
  padding-block: 0.45rem;
  border-radius: var(--radius-full);
  border: 1px solid rgba(148, 163, 184, 0.45);
  background: rgba(15, 23, 42, 0.9);
  color: var(--color-text);
  font-size: 0.85rem;
  cursor: pointer;
}

.bpw-header__menu-toggle-box {
  position: relative;
  width: 1.25rem;
  height: 1.05rem;
}

.bpw-header__menu-toggle-line {
  position: absolute;
  left: 0;
  right: 0;
  height: 2px;
  border-radius: 999px;
  background: rgba(226, 232, 240, 0.95);
  transition: transform var(--transition-base), opacity var(--transition-base), top var(--transition-base), bottom var(--transition-base);
}

.bpw-header__menu-toggle-line:first-child {
  top: 0;
}

.bpw-header__menu-toggle-line:last-child {
  bottom: 0;
}

.bpw-header__menu-toggle-text {
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

/* Responsive layout */
@media (max-width: 900px) {
  .bpw-header__inner {
    flex-wrap: wrap;
    row-gap: var(--space-3);
  }

  .bpw-header__menu-toggle {
    display: inline-flex;
  }

  .bpw-header__nav {
    order: 3;
    width: 100%;
    padding: 0;
    border: 0;
    border-radius: 0;
    background: radial-gradient(circle at top left, rgba(56, 189, 248, 0.2), transparent 55%), rgba(15, 23, 42, 0.96);
    box-shadow: none;
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-4);
    max-height: 0;
    opacity: 0;
    overflow: hidden;
    pointer-events: none;
    transform: translateY(-0.4rem);
    transition: max-height var(--transition-base), opacity var(--transition-base), transform var(--transition-base);
  }

  .bpw-header__nav-list {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-3);
  }

  .bpw-header__nav-link {
    font-size: 1rem;
  }

  .bpw-header__cta {
    width: 100%;
  }

  .bpw-header__cta-primary {
    width: 100%;
    justify-content: center;
  }

  .bpw-header--nav-open .bpw-header__nav {
    margin-top: var(--space-2);
    padding: var(--space-4);
    border: 1px solid rgba(59, 130, 246, 0.35);
    border-radius: var(--radius-xl);
    box-shadow: 0 16px 40px rgba(2, 6, 23, 0.6);
    opacity: 1;
    max-height: 32rem;
    pointer-events: auto;
    transform: translateY(0);
  }

  .bpw-header--nav-open .bpw-header__menu-toggle-line:first-child {
    top: 0.5rem;
    transform: rotate(45deg);
  }

  .bpw-header--nav-open .bpw-header__menu-toggle-line:last-child {
    bottom: 0.5rem;
    transform: rotate(-45deg);
  }
}

/* Focus-visible overrides for key controls */
.bpw-header__menu-toggle:focus-visible,
.bpw-header__nav-link:focus-visible,
.bpw-header__cta-primary:focus-visible,
.bpw-header__logo-link:focus-visible {
  outline: none;
  box-shadow: var(--shadow-focus);
}