/* ============================================================
   SkyAirways - Channel Navigation Panel (J-5A)
   Floating left-edge entry point. Theme-aware, responsive, WCAG 2.1 AA.
   ============================================================ */

:root {
  --rb-nav-bg: #ffffff;
  /* Fallbacks are load-bearing: the six channel pages load this file WITHOUT
     theme.css, so --rb-navy/--rb-yellow are undefined there. Without a
     fallback the whole declaration is invalid, --rb-nav-fg resolves to
     "unset", and icon/label colour silently inherits from the page - which is
     why the monochrome drawer icons vanished on the dark voice page. */
  --rb-nav-fg: var(--rb-navy, #103A63);
  --rb-nav-muted: #6b7280;
  --rb-nav-border: #e5e7eb;
  --rb-nav-hover: #f3f4f6;
  --rb-nav-accent: var(--rb-yellow, #1BB8F5);
  --rb-nav-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
  --rb-nav-backdrop: rgba(0, 0, 0, 0.35);
  --rb-nav-toggle-bg: var(--rb-navy, #103A63);
}

/* Scoped border-box. channel-nav.css sets no box-sizing of its own and relies
   on the host page having a universal reset; channel-base.css has one, but the
   voice, internal and plusgrade pages do not. There .rb-channel-nav__link
   (width:100% plus 16px side padding) overflowed its list by 32px, and since
   the list sets overflow-y:auto the other axis computes to auto too, producing
   a horizontal scrollbar with nothing to scroll to. */
.rb-channel-nav,
.rb-channel-nav *,
.rb-channel-nav *::before,
.rb-channel-nav *::after {
  box-sizing: border-box;
}

[data-theme="dark"] {
  --rb-nav-bg: #1f2937;
  --rb-nav-fg: #f3f4f6;
  --rb-nav-muted: #9ca3af;
  --rb-nav-border: #374151;
  --rb-nav-hover: #111827;
  --rb-nav-accent: var(--rb-yellow, #1BB8F5);
  --rb-nav-shadow: 0 10px 30px rgba(0, 0, 0, 0.55);
  --rb-nav-backdrop: rgba(0, 0, 0, 0.6);
  --rb-nav-toggle-bg: #0b1020;
}

.rb-channel-nav {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: var(--z-nav, 9998);
  font-family: inherit;
}

/* Floating toggle button - left edge, mid-screen */
.rb-channel-nav__toggle {
  position: fixed;
  left: 14px;
  top: 50%;
  transform: translateY(-50%);
  width: 48px;
  height: 48px;
  border-radius: 50%;
  border: 2px solid var(--rb-nav-accent);
  background: var(--rb-nav-toggle-bg);
  box-shadow: var(--rb-nav-shadow);
  cursor: pointer;
  padding: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  pointer-events: auto;
  /* Above the drawer and its overlay: the launcher doubles as the close
     control, so burying it made an open drawer look like a frozen page. */
  z-index: var(--z-launcher, 10000);
  transition: transform 0.18s ease, box-shadow 0.18s ease;
}

.rb-channel-nav__toggle:hover {
  transform: translateY(-50%) scale(1.05);
  box-shadow: 0 14px 36px rgba(0, 0, 0, 0.25);
}

.rb-channel-nav__toggle:focus-visible {
  outline: 3px solid var(--rb-nav-accent);
  outline-offset: 3px;
}

.rb-channel-nav__toggle-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

/* Backdrop */
.rb-channel-nav__backdrop {
  position: fixed;
  inset: 0;
  background: var(--rb-nav-backdrop);
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.2s ease, visibility 0.2s ease;
  pointer-events: none;
  z-index: var(--z-drawer-overlay, 9998);
}

.rb-channel-nav__backdrop--visible {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
}

/* Drawer - slides in from left */
.rb-channel-nav__drawer {
  position: fixed;
  top: 0;
  left: 0;
  width: 300px;
  max-width: 90vw;
  height: 100vh;
  background: var(--rb-nav-bg);
  color: var(--rb-nav-fg);
  box-shadow: var(--rb-nav-shadow);
  transform: translateX(-105%);
  /* W-25: visibility, not transform alone.
     The drawer used to be pushed off-screen by transform only, which moves it
     visually but leaves it VISIBLE to assistive technology: a screen reader
     could still read the closed drawer's channel list, and its links stayed in
     the tab order. Worse, the wrapper carries aria-live, so anything changing
     inside a "closed" drawer would have been announced.
     visibility: hidden takes it out of the accessibility tree AND out of the
     tab order, which is exactly what the sibling .rb-channel-nav__backdrop has
     always done. Transitioned alongside transform so the slide-out still plays:
     visibility flips in one step at the END when hiding, and immediately when
     showing, so the animation is unchanged in both directions. */
  visibility: hidden;
  transition: transform 0.28s cubic-bezier(0.4, 0, 0.2, 1), visibility 0.28s ease;
  display: flex;
  flex-direction: column;
  pointer-events: auto;
  z-index: var(--z-drawer, 9999);
  border-right: 1px solid var(--rb-nav-border);
}

.rb-channel-nav__drawer--open {
  transform: translateX(0);
  visibility: visible;
}

/* Drawer header */
.rb-channel-nav__header {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 18px 16px;
  border-bottom: 1px solid var(--rb-nav-border);
  background: linear-gradient(135deg, var(--rb-nav-toggle-bg), #2a3078);
  color: #fff;
}

.rb-channel-nav__brand-img {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  object-fit: cover;
  flex-shrink: 0;
}

.rb-channel-nav__brand-text {
  flex: 1;
  font-size: 15px;
  font-weight: 600;
}

.rb-channel-nav__close {
  background: transparent;
  border: 0;
  color: #fff;
  font-size: 26px;
  line-height: 1;
  cursor: pointer;
  padding: 4px 8px;
  border-radius: 4px;
}

.rb-channel-nav__close:hover {
  background: rgba(255, 255, 255, 0.15);
}

.rb-channel-nav__close:focus-visible {
  outline: 2px solid var(--rb-nav-accent);
  outline-offset: 2px;
}

/* List */
.rb-channel-nav__list {
  list-style: none;
  margin: 0;
  padding: 8px 0;
  flex: 1;
  overflow-y: auto;
}

.rb-channel-nav__item {
  margin: 0;
}

/* Separator between channels (1-6) and Services (Plusgrade) */
.rb-channel-nav__divider {
  height: 1px;
  background: var(--rb-nav-border, #e5e7eb);
  margin: 10px 16px;
  list-style: none;
  border: 0;
}
[data-theme="dark"] .rb-channel-nav__divider {
  background: var(--rb-nav-border, #374151);
}

.rb-channel-nav__link {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 12px 16px;
  color: var(--rb-nav-fg);
  text-decoration: none;
  background: transparent;
  border: 0;
  width: 100%;
  text-align: left;
  cursor: pointer;
  font-family: inherit;
  font-size: 15px;
  transition: background-color 0.15s ease, padding-left 0.15s ease;
}

.rb-channel-nav__link:hover {
  background: var(--rb-nav-hover);
  padding-left: 20px;
}

.rb-channel-nav__link:focus-visible {
  outline: 2px solid var(--rb-nav-accent);
  outline-offset: -2px;
}

.rb-channel-nav__icon {
  width: 32px;
  height: 32px;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 8px;
  background: var(--rb-nav-hover);
  color: var(--rb-nav-fg);
}

.rb-channel-nav__icon img {
  width: 22px;
  height: 22px;
  object-fit: contain;
}

.rb-channel-nav__label {
  flex: 1;
}

/* Footer */
.rb-channel-nav__footer {
  padding: 14px 16px;
  border-top: 1px solid var(--rb-nav-border);
  color: var(--rb-nav-muted);
  font-size: 12px;
  text-align: center;
}

.rb-channel-nav__footer strong {
  color: var(--rb-nav-accent);
}

/* Responsive - hide on small screens (mobile menu should include the links) */
@media (max-width: 767px) {
  .rb-channel-nav--mobile-hidden .rb-channel-nav__toggle {
    display: none;
  }
}

/* Respect reduced motion */
@media (prefers-reduced-motion: reduce) {
  .rb-channel-nav__toggle,
  .rb-channel-nav__drawer,
  .rb-channel-nav__backdrop {
    transition: none !important;
  }
}