/* =============================================================================
   COMPONENTS — global chrome and reusable primitives
   Buttons, badges, header/mega menu, mobile drawer, metric bars, footer.
   Chapter-specific styling lives in chapters.css. Class names stay stable
   for the Phase 2 PHP port (header.php / footer.php partials).
   ============================================================================= */

/* ---- Buttons ------------------------------------------------------------ */
.btn {
  --btn-bg: transparent;
  --btn-fg: var(--color-text-primary);
  --btn-border: var(--color-border-default);
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  min-height: 2.875rem; /* >= 44px touch target */
  padding: var(--space-3) var(--space-6);
  border: 1px solid var(--btn-border);
  border-radius: var(--radius-pill);
  background: var(--btn-bg);
  color: var(--btn-fg);
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: var(--weight-medium);
  letter-spacing: 0.02em;
  white-space: nowrap;
  overflow: hidden;
  isolation: isolate;
  transition: transform var(--duration-fast) var(--ease-out),
    background-color var(--duration-base) var(--ease-out),
    border-color var(--duration-base) var(--ease-out),
    box-shadow var(--duration-base) var(--ease-out),
    color var(--duration-base) var(--ease-out);
}

/* Sheen sweep on hover/focus (soft-light so label stays readable) */
.btn::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(
    110deg,
    transparent 30%,
    rgba(255, 255, 255, 0.28) 48%,
    transparent 66%
  );
  transform: translateX(-120%);
  transition: transform var(--duration-slower) var(--ease-out);
  pointer-events: none;
  mix-blend-mode: soft-light;
}

.btn:hover,
.btn:focus-visible {
  transform: translateY(-2px);
}

.btn:hover::after,
.btn:focus-visible::after {
  transform: translateX(120%);
}

.btn:active {
  transform: translateY(0);
}

/* Traveling edge glow — a conic highlight orbits the pill's border.
   @property lets the angle interpolate; browsers without it just show the
   static ring (graceful). */
@property --btn-angle {
  syntax: "<angle>";
  inherits: false;
  initial-value: 0deg;
}

.btn--primary::before,
.btn--secondary::before {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  padding: 1.5px;
  background: conic-gradient(
    from var(--btn-angle),
    transparent 0deg 250deg,
    var(--btn-glow-color, var(--color-accent)) 305deg,
    transparent 360deg
  );
  -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  -webkit-mask-composite: xor;
  mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  mask-composite: exclude;
  opacity: 0.55;
  pointer-events: none;
  animation: btn-edge-travel 3.4s linear infinite;
}

.btn--primary::before {
  --btn-glow-color: rgba(255, 255, 255, 0.9);
}

.btn--primary:hover::before,
.btn--primary:focus-visible::before,
.btn--secondary:hover::before,
.btn--secondary:focus-visible::before {
  opacity: 1;
}

@keyframes btn-edge-travel {
  to {
    --btn-angle: 360deg;
  }
}

@media (prefers-reduced-motion: reduce) {
  .btn--primary::before,
  .btn--secondary::before {
    animation: none;
    background: conic-gradient(
      from 0deg,
      var(--btn-glow-color, var(--color-accent)) 0deg 360deg
    );
    opacity: 0.3;
  }
}

.btn--primary {
  --btn-bg: var(--color-accent);
  --btn-fg: var(--color-accent-contrast);
  --btn-border: transparent;
  box-shadow: var(--shadow-glow-accent);
}

.btn--primary:hover,
.btn--primary:focus-visible {
  --btn-bg: var(--color-accent-strong);
  box-shadow: 0 0 0 1px var(--color-accent-muted),
    0 0 28px -4px var(--color-accent-glow),
    0 24px 60px -18px var(--color-accent-glow);
}

.btn--secondary:hover,
.btn--secondary:focus-visible {
  --btn-border: color-mix(in srgb, var(--color-accent) 45%, var(--color-border-default));
  background: var(--color-bg-overlay);
  box-shadow: 0 0 0 1px var(--color-accent-muted),
    0 12px 36px -16px var(--color-accent-glow);
}

.btn--ghost {
  --btn-border: transparent;
  padding-inline: var(--space-3);
}

.btn--ghost:hover {
  --btn-fg: var(--color-accent);
  transform: translateY(0);
}

.btn--disabled,
.btn[aria-disabled="true"] {
  --btn-bg: var(--color-bg-overlay);
  --btn-fg: var(--color-text-muted);
  --btn-border: var(--color-border-subtle);
  cursor: not-allowed;
  box-shadow: none;
}

.btn--disabled:hover,
.btn[aria-disabled="true"]:hover {
  transform: none;
}

.btn--block {
  width: 100%;
}

.btn__arrow {
  transition: transform var(--duration-base) var(--ease-out);
}

.btn:hover .btn__arrow {
  transform: translateX(4px);
}

/* ---- Badges / status chips ----------------------------------------------
   Static by design (Round 2): no breathing, no pulsing dot. */
.badge {
  --badge-color: var(--color-neutral);
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: 0.3rem var(--space-3);
  border: 1px solid color-mix(in srgb, var(--badge-color) 40%, transparent);
  border-radius: var(--radius-pill);
  background: color-mix(in srgb, var(--badge-color) 12%, transparent);
  color: var(--badge-color);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: var(--weight-medium);
  letter-spacing: var(--tracking-wide);
  text-transform: uppercase;
  white-space: nowrap;
}

.badge::before {
  content: "";
  width: 0.4rem;
  height: 0.4rem;
  border-radius: 50%;
  background: currentColor;
}

.badge--live {
  --badge-color: var(--color-success);
}

.badge--available {
  --badge-color: var(--color-accent);
}

.badge--partial {
  --badge-color: var(--color-warning);
}

.badge--soon {
  --badge-color: var(--color-soon);
}

.badge--dev {
  --badge-color: var(--color-soon);
}

/* ---- Header + nav ------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: var(--z-header);
  height: var(--header-height);
  display: flex;
  align-items: center;
  border-bottom: 1px solid transparent;
  /* Scrim keeps nav readable over immersive chapter backdrops */
  background: color-mix(in srgb, var(--color-bg-base) 74%, transparent);
  backdrop-filter: blur(14px);
  transition: border-color var(--duration-base) var(--ease-out),
    background-color var(--duration-base) var(--ease-out);
}

.site-header.is-scrolled {
  border-bottom-color: var(--color-border-subtle);
  background: color-mix(in srgb, var(--color-bg-base) 90%, transparent);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-6);
  width: 100%;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  font-family: var(--font-display);
  font-weight: var(--weight-bold);
  font-size: var(--text-xl);
  letter-spacing: var(--tracking-tight);
  color: var(--color-text-primary);
}

.brand__mark {
  display: grid;
  place-items: center;
  width: 2.1rem;
  height: 2.1rem;
  border-radius: var(--radius-md);
  overflow: hidden;
}

.brand__mark img {
  width: 100%;
  height: 100%;
  object-fit: contain;
}

/* Primary nav (desktop) */
.primary-nav {
  display: none;
}

.primary-nav__list {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.nav-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-pill);
  color: var(--color-text-secondary);
  font-size: var(--text-sm);
  font-weight: var(--weight-medium);
  transition: color var(--duration-fast) var(--ease-out),
    background-color var(--duration-fast) var(--ease-out);
}

.nav-link:hover,
.nav-link[aria-expanded="true"] {
  color: var(--color-text-primary);
  background: var(--color-bg-overlay);
}

.nav-link__chevron {
  transition: transform var(--duration-base) var(--ease-out);
}

.nav-link[aria-expanded="true"] .nav-link__chevron {
  transform: rotate(180deg);
}

.header-actions {
  display: none;
  align-items: center;
  gap: var(--space-3);
}

/* Language picker button (header) */
.lang-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-3);
  border: 1px solid var(--color-border-default);
  border-radius: var(--radius-pill);
  color: var(--color-text-secondary);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: var(--tracking-wide);
  text-transform: uppercase;
  transition: color var(--duration-fast) var(--ease-out),
    border-color var(--duration-fast) var(--ease-out);
}

.lang-btn:hover {
  color: var(--color-text-primary);
  border-color: var(--color-border-emphasis);
}

/* ---- Mega menu (desktop) ------------------------------------------------ */
.mega {
  position: absolute;
  left: 50%;
  top: calc(var(--header-height) - 0.5rem);
  transform: translate(-50%, -10px) scale(0.985);
  transform-origin: top center;
  width: min(920px, calc(100vw - 3rem));
  z-index: var(--z-mega);
  padding: var(--space-6);
  border: 1px solid var(--color-border-default);
  border-radius: var(--radius-xl);
  background: color-mix(in srgb, var(--color-bg-raised) 96%, transparent);
  backdrop-filter: blur(18px);
  box-shadow: var(--shadow-lg), 0 0 80px -30px var(--color-accent-glow);
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  filter: blur(4px);
  transition: opacity var(--duration-base) var(--ease-out),
    transform var(--duration-slow) var(--ease-spring),
    filter var(--duration-base) var(--ease-out),
    visibility var(--duration-base);
}

/* Hairline accent along the top edge of the panel */
.mega::before {
  content: "";
  position: absolute;
  top: 0;
  left: 10%;
  right: 10%;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--color-accent-glow), transparent);
}

.mega.is-open {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
  filter: blur(0);
  transform: translate(-50%, 0) scale(1);
}

.mega__grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-3);
}

.mega__item {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: var(--space-4);
  padding: var(--space-4);
  border-radius: var(--radius-lg);
  border: 1px solid transparent;
  background: transparent;
  color: inherit;
  font: inherit;
  cursor: pointer;
  text-align: left;
  width: 100%;
  opacity: 0;
  transform: translateY(10px);
  transition: background-color var(--duration-fast) var(--ease-out),
    border-color var(--duration-fast) var(--ease-out),
    opacity var(--duration-slow) var(--ease-out),
    transform var(--duration-slow) var(--ease-spring);
}

/* Staggered rise once the panel opens */
.mega.is-open .mega__item {
  opacity: 1;
  transform: translateY(0);
}

.mega.is-open .mega__item:nth-child(1) { transition-delay: 40ms; }
.mega.is-open .mega__item:nth-child(2) { transition-delay: 90ms; }
.mega.is-open .mega__item:nth-child(3) { transition-delay: 140ms; }
.mega.is-open .mega__item:nth-child(4) { transition-delay: 190ms; }

/* No delay when closing so items never linger */
.mega:not(.is-open) .mega__item {
  transition-delay: 0ms;
}

.mega__item:hover {
  background: var(--color-bg-overlay);
  border-color: var(--color-border-subtle);
}

.mega__icon {
  display: grid;
  place-items: center;
  width: 2.75rem;
  height: 2.75rem;
  border-radius: var(--radius-md);
  background: var(--color-bg-overlay);
  border: 1px solid var(--color-border-subtle);
  color: var(--color-accent);
  transition: transform var(--duration-base) var(--ease-spring),
    border-color var(--duration-base) var(--ease-out),
    box-shadow var(--duration-base) var(--ease-out);
}

.mega__item:hover .mega__icon {
  transform: translateY(-2px) scale(1.06) rotate(-3deg);
  border-color: color-mix(in srgb, var(--color-accent) 35%, transparent);
  box-shadow: 0 8px 24px -10px var(--color-accent-glow);
}

.mega__title {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-family: var(--font-display);
  font-size: var(--text-base);
  font-weight: var(--weight-semibold);
  color: var(--color-text-primary);
}

.mega__desc {
  margin-top: var(--space-1);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

.mega__footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  margin-top: var(--space-5);
  padding-top: var(--space-5);
  border-top: 1px solid var(--color-border-subtle);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

/* ---- Hamburger + mobile drawer ----------------------------------------- */
.menu-toggle {
  display: inline-grid;
  place-items: center;
  width: 2.75rem;
  height: 2.75rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border-default);
  color: var(--color-text-primary);
}

.menu-toggle__bars {
  position: relative;
}

.menu-toggle__bars,
.menu-toggle__bars::before,
.menu-toggle__bars::after {
  content: "";
  display: block;
  width: 18px;
  height: 2px;
  background: currentColor;
  border-radius: 2px;
  transition: transform var(--duration-base) var(--ease-out),
    opacity var(--duration-fast) var(--ease-out);
}

.menu-toggle__bars::before {
  position: absolute;
  transform: translateY(-6px);
}

.menu-toggle__bars::after {
  position: absolute;
  transform: translateY(6px);
}

.menu-toggle[aria-expanded="true"] .menu-toggle__bars {
  background: transparent;
}

.menu-toggle[aria-expanded="true"] .menu-toggle__bars::before {
  transform: translateY(0) rotate(45deg);
}

.menu-toggle[aria-expanded="true"] .menu-toggle__bars::after {
  transform: translateY(0) rotate(-45deg);
}

.drawer {
  position: fixed;
  inset: 0;
  z-index: var(--z-drawer);
  display: flex;
  flex-direction: column;
  padding: calc(var(--header-height) + var(--space-4)) var(--container-pad) var(--space-8);
  background: color-mix(in srgb, var(--color-bg-base) 97%, transparent);
  backdrop-filter: blur(18px);
  overflow-y: auto;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-2%);
  transition: opacity var(--duration-base) var(--ease-out),
    transform var(--duration-base) var(--ease-out),
    visibility var(--duration-base);
}

.drawer.is-open {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.drawer__group-label {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: var(--tracking-wider);
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin-bottom: var(--space-4);
}

.drawer__item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  padding: var(--space-4) 0;
  border-bottom: 1px solid var(--color-border-subtle);
  color: var(--color-text-primary);
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: var(--weight-semibold);
}

.drawer__links {
  margin-top: var(--space-8);
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.drawer__link {
  display: block;
  width: 100%;
  padding: var(--space-3) 0;
  border: none;
  background: none;
  color: var(--color-text-secondary);
  font: inherit;
  font-size: var(--text-lg);
  font-weight: var(--weight-medium);
  text-align: left;
  cursor: pointer;
}

.drawer__cta {
  margin-top: var(--space-8);
}

/* ---- Metric bars (web chapter, SEO beat) --------------------------------- */
.metric {
  margin-bottom: var(--space-4);
}

.metric__label {
  display: flex;
  justify-content: space-between;
  font-size: var(--text-sm);
  margin-bottom: var(--space-2);
}

.metric__value {
  font-family: var(--font-mono);
  color: var(--color-accent);
  font-variant-numeric: tabular-nums;
}

.metric__track {
  height: 8px;
  border-radius: var(--radius-pill);
  background: var(--color-bg-overlay);
  overflow: hidden;
}

.metric__fill {
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--color-accent-secondary), var(--color-accent));
  width: var(--fill, 0%);
}

/* ---- Footer ------------------------------------------------------------- */
.site-footer {
  border-top: 1px solid var(--color-border-subtle);
  background: var(--color-bg-raised);
  padding-block: var(--space-16) var(--space-8);
}

.footer__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-10);
}

.footer__brand {
  max-width: 22rem;
}

.footer__tagline {
  margin-top: var(--space-4);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

.footer__col-title {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: var(--tracking-wider);
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin-bottom: var(--space-4);
}

.footer__links {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.footer__link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  color: var(--color-text-secondary);
  font-size: var(--text-sm);
  width: fit-content;
  transition: color var(--duration-fast) var(--ease-out);
}

.footer__link:hover {
  color: var(--color-accent);
}

.footer__social {
  display: flex;
  gap: var(--space-3);
  margin-top: var(--space-5);
}

.social-btn {
  display: grid;
  place-items: center;
  width: 2.5rem;
  height: 2.5rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border-subtle);
  color: var(--color-text-secondary);
  transition: color var(--duration-fast) var(--ease-out),
    border-color var(--duration-fast) var(--ease-out),
    transform var(--duration-fast) var(--ease-out);
}

.social-btn:hover {
  color: var(--color-accent);
  border-color: var(--color-border-emphasis);
  transform: translateY(-2px);
}

.footer__bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  margin-top: var(--space-16);
  padding-top: var(--space-6);
  border-top: 1px solid var(--color-border-subtle);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

.footer__legal {
  display: flex;
  gap: var(--space-5);
}

.footer__legal a:hover {
  color: var(--color-text-secondary);
}

@media (min-width: 640px) {
  .footer__grid {
    grid-template-columns: 1.5fr 1fr 1fr;
  }
}

@media (min-width: 768px) {
  .footer__grid {
    grid-template-columns: 2fr 1fr 1fr;
  }
}

@media (min-width: 1024px) {
  .primary-nav {
    display: block;
  }

  .header-actions {
    display: flex;
  }

  .menu-toggle {
    display: none;
  }
}