/**
 * TRANHATAM.COM — App Shell CSS v1.0
 * Mobile PWA layout: bottom tab bar, safe area, transitions, skeleton.
 * Import SAU public.css.
 */

/* ── Import design tokens ─────────────────────────────────── */
@import url("/brand-system/tranhatam/design-tokens.css");

/* ── App Root Layout ────────────────────────────────────── */
.app-root {
  display: flex;
  flex-direction: column;
  min-height: 100dvh;
  padding-bottom: env(safe-area-inset-bottom, 0);
}

.app-main {
  flex: 1 1 auto;
  overflow-y: auto;
  overscroll-behavior-y: contain;
}

/* ── Bottom Tab Bar ─────────────────────────────────────── */
.app-bottom-nav {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  z-index: var(--z-bottom-nav, 200);
  display: flex;
  justify-content: space-around;
  align-items: center;
  height: calc(var(--app-bottom-nav-height, 56px) + env(safe-area-inset-bottom, 0px));
  padding-bottom: env(safe-area-inset-bottom, 0px);
  background: var(--color-app-bottom-nav-bg, rgba(255,255,255,0.92));
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  border-top: 1px solid var(--color-app-bottom-nav-border, #E5E5E8);
  box-shadow: var(--shadow-bottom-nav, 0 -2px 10px rgba(15,15,15,0.06));
}

.app-bottom-nav__item {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 2px;
  flex: 1;
  min-width: 0;
  height: var(--app-bottom-nav-height, 56px);
  padding: 4px;
  text-decoration: none;
  color: var(--color-app-tab-inactive, #6E6E76);
  transition: color var(--duration-sm, 200ms) var(--ease-standard);
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
}

.app-bottom-nav__item:focus,
.app-bottom-nav__item:active {
  outline: none;
}

.app-bottom-nav__item[aria-current="page"],
.app-bottom-nav__item--active {
  color: var(--color-app-tab-active, #1A1A2E);
}

.app-bottom-nav__item[aria-current="page"] .app-bottom-nav__label,
.app-bottom-nav__item--active .app-bottom-nav__label {
  font-weight: var(--font-weight-semibold, 600);
}

.app-bottom-nav__icon {
  width: var(--app-icon-size, 24px);
  height: var(--app-icon-size, 24px);
  flex-shrink: 0;
}

.app-bottom-nav__label {
  font-size: var(--font-size-caption, 0.75rem);
  line-height: 1.2;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 100%;
}

/* Indicator line for active tab */
.app-bottom-nav__item[aria-current="page"]::before,
.app-bottom-nav__item--active::before {
  content: "";
  position: absolute;
  top: 0;
  width: 32px;
  height: 3px;
  border-radius: 0 0 2px 2px;
  background: var(--color-app-tab-indicator, #D4A373);
}

/* Hide bottom nav on desktop (≥768px) — optional, web stays normal */
@media (min-width: 768px) {
  .app-bottom-nav {
    display: none;
  }
  .app-root {
    padding-bottom: 0;
  }
}

/* ── Collapsible Header ─────────────────────────────────── */
.app-header {
  position: sticky;
  top: 0;
  z-index: var(--z-header, 200);
  height: var(--app-header-height, 56px);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--space-5, 16px);
  background: var(--color-app-header-bg, #1A1A2E);
  color: var(--color-app-header-text, #FFFFFF);
  transition: transform var(--duration-sm, 200ms) var(--ease-standard),
              opacity var(--duration-sm, 200ms) var(--ease-standard);
}

.app-header--hidden {
  transform: translateY(-100%);
  opacity: 0;
}

/* ── Page Transitions ───────────────────────────────────── */
.app-page {
  opacity: 1;
  transform: translateX(0);
  transition: opacity var(--duration-md, 300ms) var(--ease-standard),
              transform var(--duration-md, 300ms) var(--ease-standard);
}

.app-page--enter {
  opacity: 0;
  transform: translateX(20px);
}

.app-page--exit {
  opacity: 0;
  transform: translateX(-20px);
}

/* ── Skeleton Loading ───────────────────────────────────── */
.app-skeleton {
  background: linear-gradient(
    90deg,
    var(--color-paper-50, #FAFAFA) 25%,
    var(--color-ink-100, #E5E5E8) 50%,
    var(--color-paper-50, #FAFAFA) 75%
  );
  background-size: 200% 100%;
  animation: appSkeletonPulse 1.5s ease-in-out infinite;
  border-radius: var(--radius-md, 8px);
}

@keyframes appSkeletonPulse {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

/* ── Safe Area Helpers ────────────────────────────────── */
@supports (padding-top: env(safe-area-inset-top)) {
  .app-header {
    padding-top: env(safe-area-inset-top);
    height: calc(var(--app-header-height, 56px) + env(safe-area-inset-top));
  }
}

/* ── Touch Targets ──────────────────────────────────────── */
.app-touch-target {
  min-height: var(--app-touch-target, 44px);
  min-width: var(--app-touch-target, 44px);
}

/* ── Dark Reader Theme Override ───────────────────────── */
[data-reader-theme="dark"] .app-bottom-nav {
  background: rgba(15, 15, 15, 0.92);
  border-top-color: var(--color-dark-border, #2D2D33);
}

[data-reader-theme="dark"] .app-bottom-nav__item {
  color: var(--color-dark-muted, #A0A0A8);
}

[data-reader-theme="dark"] .app-bottom-nav__item[aria-current="page"],
[data-reader-theme="dark"] .app-bottom-nav__item--active {
  color: var(--color-dark-text, #F5F5F5);
}