/* ============================================================
   Layout foundation — shell, z-index, containment, grids
   ============================================================ */

:root {
  --z-header: 90;
  --z-tabbar: 100;
  --z-install: 110;
  --z-checkbar: 120;
  --z-toast: 130;
  --z-tooltip: 140;
  --z-offline: 150;
  --z-modal: 200;
  --chrome-pad-x: clamp(var(--sp-4), 4vw, var(--sp-8));
}

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

body {
  min-height: 100%;
  min-height: 100dvh;
  overflow-x: clip;
}

#app {
  position: relative;
  isolation: isolate;
  contain: layout style;
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding:
    var(--sp-5) var(--chrome-pad-x)
    calc(var(--tabbar-h) + var(--sp-5) + env(safe-area-inset-bottom));
  min-height: 100dvh;
  min-width: 0;
  overflow-x: clip;
}

#app.immersive {
  padding-bottom: calc(var(--checkbar-h) + var(--sp-4) + env(safe-area-inset-bottom));
}

#app.immersive.no-checkbar {
  padding-bottom: calc(var(--sp-6) + env(safe-area-inset-bottom));
}

body.has-checkbar #app.immersive {
  padding-bottom: calc(var(--checkbar-h) + var(--sp-4) + env(safe-area-inset-bottom));
}

/* Sticky screen header */
.app-header {
  position: sticky;
  top: 0;
  z-index: var(--z-header);
  margin: calc(-1 * var(--sp-5)) calc(-1 * var(--chrome-pad-x)) var(--sp-4);
  padding: var(--sp-3) var(--chrome-pad-x);
  background: color-mix(in srgb, var(--bg) 92%, transparent);
  backdrop-filter: blur(12px) saturate(1.1);
  -webkit-backdrop-filter: blur(12px) saturate(1.1);
  border-bottom: 1px solid color-mix(in srgb, var(--line) 55%, transparent);
}

/* Chrome layers */
.tabbar { z-index: var(--z-tabbar); }
.install-banner { z-index: var(--z-install); }
.checkbar { z-index: var(--z-checkbar); }
.toast { z-index: var(--z-toast); }
.tw-pop { z-index: var(--z-tooltip); }
.offline-bar { z-index: var(--z-offline); }
.modal-backdrop { z-index: var(--z-modal); }
.modal-sheet { z-index: calc(var(--z-modal) + 1); }

/* Surfaces — nothing escapes the box */
.card,
.bento-tile,
.node,
.level-group,
.plan-card,
.home-alert,
.quest-card,
.shop-item,
.word-card,
.lesson-word-card {
  max-width: 100%;
  min-width: 0;
  overflow: hidden;
}

/* Flex / grid safety */
.stack { display: grid; gap: var(--sp-3); min-width: 0; }
.stack > * { min-width: 0; }

.row {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  min-width: 0;
  flex-wrap: wrap;
}

.row > * { min-width: 0; }

.app-header {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--sp-2);
  align-items: start;
}

.app-header .title { display: grid; gap: 2px; min-width: 0; }
.app-header .title h1 {
  margin: 0;
  overflow-wrap: anywhere;
  line-height: 1.15;
  font-size: var(--text-2xl);
}

.app-header .title small {
  color: var(--muted-2);
  font-size: var(--text-sm);
  line-height: 1.4;
  overflow-wrap: anywhere;
}

.app-header > .stat-pills,
.app-header > .btn,
.app-header > button {
  justify-self: start;
  max-width: 100%;
}

@media (min-width: 520px) {
  .app-header {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
    gap: var(--sp-3);
  }
  .app-header > .stat-pills,
  .app-header > .btn,
  .app-header > button {
    grid-column: 2;
    grid-row: 1;
    justify-self: end;
  }
}

.stat-pills {
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-2);
  align-items: center;
}

.pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  flex-shrink: 0;
  white-space: nowrap;
}

.plan-grid {
  display: grid;
  gap: var(--sp-3);
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 240px), 1fr));
  align-items: stretch;
}

.bento {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(var(--sp-3), 2.5vw, var(--sp-4));
  margin-bottom: var(--sp-6);
  min-width: 0;
}

.home-hero {
  display: grid;
  gap: var(--sp-3);
  margin-bottom: var(--sp-4);
  min-width: 0;
}

.home-hero > * { min-width: 0; }

@media (min-width: 720px) {
  .home-hero {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
    align-items: stretch;
  }
}

.bento-compact {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

@media (max-width: 480px) {
  .bento-compact { grid-template-columns: minmax(0, 1fr); }
}

.node {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  min-width: 0;
}

.node .meta { flex: 1; min-width: 0; }
.node .meta .t {
  display: block;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.node .go { margin-left: auto; flex-shrink: 0; }

.lesson-top {
  display: flex;
  align-items: center;
  gap: var(--sp-2);
  flex-wrap: wrap;
  min-width: 0;
  margin-bottom: var(--sp-4);
}

.lesson-top .progress { flex: 1 1 140px; min-width: 0; }

.lesson-shell { display: grid; gap: var(--sp-3); min-width: 0; }

.choice-grid,
.exercise-card .options {
  display: grid;
  gap: var(--sp-3);
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 148px), 1fr));
}

.practice-grid {
  display: grid;
  gap: var(--sp-4);
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  align-items: stretch;
}

.practice-grid .practice-tile {
  min-width: 0;
}

@media (min-width: 640px) {
  .practice-grid .practice-tile:first-child {
    grid-column: 1 / -1;
  }
}

.dict-stats {
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-2);
  margin-bottom: var(--sp-3);
}

.dict-stats .ds-chip { min-width: 0; }

.chip-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-2);
  align-items: center;
  margin-bottom: var(--sp-3);
}

.profile-hero {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--sp-3);
}

.profile-hero .ph-meta { flex: 1; min-width: 0; }
.profile-hero .ph-rings { display: flex; flex-wrap: wrap; gap: var(--sp-2); }

body.has-checkbar .install-banner {
  bottom: calc(var(--checkbar-h) + var(--sp-3) + env(safe-area-inset-bottom, 0px));
}

.install-banner {
  bottom: calc(var(--tabbar-h) + var(--sp-3) + env(safe-area-inset-bottom, 0px));
  left: var(--chrome-pad-x);
  right: var(--chrome-pad-x);
}

@media (prefers-reduced-motion: reduce) {
  #app.screen-enter { animation: none !important; }
}