/* ==========================================================================
   master-deck.css
   Korean Vocabulary PWA — Master Deck Screen (Arcade Aesthetic)
   Scoped styles only. All colors via CSS custom properties.
   No raw hex/rgb/hsl values except for glow alpha overlays (consistent with layout.css).
   Hard edges, neon glows, Press Start 2P UI.
   Expandable unit → chapter → word tree with locked/unlocked states.
   Units / Chapters / Words presented as centered vertical stack.
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. MASTER DECK SCREEN LAYOUT
   -------------------------------------------------------------------------- */

#master-deck-screen,
#screen-master-deck {
  display: flex;
  flex-direction: column;
  height: 100%;
  overflow: hidden;
}

/* Header: back | centered title block | right stats */
.deck-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  padding: var(--space-md);
  flex-shrink: 0;
  border-bottom: 2px solid var(--color-text-muted);
  background-color: var(--color-background);
  z-index: 10;
}

.title-block {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
}

.subtitle {
  font-family: var(--font-display);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-top: 4px;
  line-height: 1;
}

/* Right-side stat pill */
.header-stats {
  display: flex;
  align-items: center;
  flex-shrink: 0;
}

.stat-pill {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background-color: var(--color-surface);
  border: 2px solid var(--color-primary);
  border-radius: var(--border-radius-sm);
  padding: var(--space-xs) var(--space-sm);
  min-width: 78px;
  box-shadow: 0 0 8px var(--color-primary);
}

.stat-value {
  font-family: var(--font-display);
  font-size: var(--font-size-xl);
  color: var(--color-accent);
  line-height: 1;
  letter-spacing: 0.02em;
}

.stat-label {
  font-family: var(--font-display);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  line-height: 1;
  margin-top: 2px;
}

/* --------------------------------------------------------------------------
   2. UNITS / CHAPTERS / WORDS LISTS — Vertical centered column
   -------------------------------------------------------------------------- */

.units-list {
  flex: 1;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  width: 100%;
  min-height: 0;
  scroll-behavior: smooth;
}

.chapters-list,
.words-list {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-md);
  width: 100%;
  padding: 0 var(--space-md);
}

/* Accordion containers — centered block with hard edge */
.unit-accordion,
.chapter-accordion {
  width: 100%;
  max-width: 460px;
  border: 2px solid var(--color-primary);
  border-radius: var(--border-radius-sm);
  overflow: hidden;
  background-color: var(--color-surface);
  box-shadow: 0 0 6px rgba(0, 0, 0, 0.3);
  flex-shrink: 0;
}

/* Sub-accordion (chapter) gets a top separator when inside unit */
.chapter-accordion {
  border-top: 1px solid var(--color-text-muted);
  border-left: none;
  border-right: none;
  border-bottom: none;
  border-radius: 0;
  background-color: transparent;
}

/* First chapter in list removes top border */
.chapter-accordion:first-child {
  border-top: none;
}

/* --------------------------------------------------------------------------
   3. ACCORDION HEADERS (Unit + Chapter)
   Extend .btn base with full-width flex behavior
   -------------------------------------------------------------------------- */

.unit-header,
.chapter-header {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-sm);
  padding: var(--space-md);
  text-align: left;
  /* .btn already provides border, color, font, min-height, transitions */
}

/* Unit header — primary color, slightly larger presence */
.unit-header {
  padding: var(--space-md);
  background-color: var(--color-surface);
}

.unit-header .unit-label {
  font-family: var(--font-display);
  font-size: var(--font-size-md);
  color: var(--color-primary);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  flex-shrink: 0;
}

.unit-header .unit-progress {
  font-family: var(--font-display);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  text-align: right;
  flex: 1;
  padding: 0 var(--space-sm);
}

/* Chapter header — secondary color for hierarchy */
.chapter-header {
  padding: var(--space-sm) var(--space-md);
  color: var(--color-secondary);
  border-color: var(--color-secondary);
  background-color: rgba(0, 0, 0, 0.15);
}

.chapter-header .chapter-label {
  font-family: var(--font-display);
  font-size: var(--font-size-sm);
  color: var(--color-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  flex-shrink: 0;
}

.chapter-header .chapter-progress {
  font-family: var(--font-display);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  text-align: right;
  flex: 1;
  padding: 0 var(--space-sm);
}

/* Chevron icon */
.chevron {
  font-size: var(--font-size-sm);
  color: inherit;
  transition: transform var(--transition-normal);
  flex-shrink: 0;
  width: 18px;
  text-align: center;
}

.unit-accordion.expanded .unit-header .chevron,
.chapter-accordion.expanded .chapter-header .chevron {
  transform: rotate(180deg);
  padding-top: var(--space-sm);
}

/* Expanded state visual lift */
.unit-accordion.expanded,
.chapter-accordion.expanded {
  box-shadow: 0 0 12px var(--color-primary);
}

/* --------------------------------------------------------------------------
   4. WORD ITEMS — Locked vs Unlocked + Leitner color coding
   -------------------------------------------------------------------------- */

.word-item {
  width: 100%;
  max-width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  padding: var(--space-sm) var(--space-md);
  background-color: var(--color-surface);
  border: 1px solid var(--color-text-muted);
  border-left-width: 4px; /* strength indicator stripe */
  border-radius: var(--border-radius-sm);
  transition:
    border-color var(--transition-fast),
    box-shadow var(--transition-fast),
    background-color var(--transition-fast);
  user-select: none;
}

/* Hover / active feedback (touch friendly) */
.word-item:active {
  transform: scale(0.985);
}

.word-item:hover {
  border-color: var(--color-primary);
  box-shadow: 0 0 8px var(--color-primary);
}

/* Leitner group color coding via left border + subtle glow */
.word-item.leitner-1 { border-left-color: var(--color-leitner-1); }
.word-item.leitner-2 { border-left-color: var(--color-leitner-2); }
.word-item.leitner-3 { border-left-color: var(--color-leitner-3); }
.word-item.leitner-4 { border-left-color: var(--color-leitner-4); }
.word-item.leitner-5 { border-left-color: var(--color-leitner-5); box-shadow: 0 0 8px var(--color-leitner-5); }

/* Locked state — dimmed, dashed, no data */
.word-item.locked {
  opacity: 0.45;
  border-style: dashed;
  border-left-width: 2px;
  border-color: var(--color-text-muted);
  background-color: var(--color-surface);
}

.word-item.locked:hover,
.word-item.locked:active {
  box-shadow: none;
  border-color: var(--color-text-muted);
  transform: none;
}

.word-item.locked .hangul {
  color: var(--color-text-muted);
}

/* Word content layout */
.word-main {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  flex: 1;
  min-width: 0;
  gap: 2px;
}

.hangul {
  font-family: var(--font-korean);
  font-weight: 900;
  font-size: var(--font-size-xl);
  color: var(--color-text);
  line-height: 1.05;
  letter-spacing: -0.01em;
}

.english {
  font-family: var(--font-body);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  line-height: 1.3;
}

/* Right side meta (badge + accuracy) */
.word-meta {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  justify-content: center;
  gap: 4px;
  flex-shrink: 0;
  text-align: right;
}

.leitner-badge {
  font-family: var(--font-display);
  font-size: var(--font-size-sm);
  padding: 1px 7px;
  border: 1px solid currentColor;
  border-radius: var(--border-radius-sm);
  line-height: 1;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

/* Color the badge to match Leitner group */
.word-item.leitner-1 .leitner-badge { color: var(--color-leitner-1); border-color: var(--color-leitner-1); }
.word-item.leitner-2 .leitner-badge { color: var(--color-leitner-2); border-color: var(--color-leitner-2); }
.word-item.leitner-3 .leitner-badge { color: var(--color-leitner-3); border-color: var(--color-leitner-3); }
.word-item.leitner-4 .leitner-badge { color: var(--color-leitner-4); border-color: var(--color-leitner-4); }
.word-item.leitner-5 .leitner-badge { color: var(--color-leitner-5); border-color: var(--color-leitner-5); }

.accuracy {
  font-family: var(--font-display);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  letter-spacing: 0.04em;
  line-height: 1;
}

/* Locked badge */
.locked-badge {
  font-family: var(--font-display);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 1px 8px;
  border: 1px dashed var(--color-text-muted);
  border-radius: var(--border-radius-sm);
  line-height: 1;
}

/* Empty state inside words-list */
.words-list .empty-state {
  width: 100%;
  padding: var(--space-lg);
  text-align: center;
  font-family: var(--font-display);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

/* --------------------------------------------------------------------------
   5. FOOTER HINT
   -------------------------------------------------------------------------- */

.deck-footer {
  flex-shrink: 0;
  padding: var(--space-md);
  text-align: center;
  border-top: 1px solid var(--color-text-muted);
  background-color: var(--color-background);
}

.hint {
  font-family: var(--font-display);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  line-height: 1.4;
}

/* --------------------------------------------------------------------------
   6. ACCESSIBILITY / REDUCED MOTION
   -------------------------------------------------------------------------- */

@media (prefers-reduced-motion: reduce) {
  .chevron,
  .unit-accordion,
  .chapter-accordion,
  .word-item {
    transition: none !important;
  }
}

/* Ensure touch targets remain comfortable inside narrow lists */
.unit-header,
.chapter-header,
.word-item {
  min-height: 48px;
}
/* === Master Deck Polish (Filter + Expandable Stats + Locked) === */

/* Filter bar */
.deck-filters {
  width: 100%;
  max-width: 460px;
  margin: 0 auto var(--space-md);
  padding: 0 var(--space-md);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-xs);
}

.deck-filters .section-label {
  font-family: var(--font-display);
  font-size: var(--font-size-sm);
  color: var(--color-secondary);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.filter-control {
  width: 100%;
  max-width: 420px;
  border: 2px solid var(--color-primary);
  border-radius: var(--border-radius-sm);
  overflow: hidden;
}

.filter-control .seg-option {
  flex: 1;
  min-height: 44px;
  font-size: var(--font-size-sm);
  letter-spacing: 0.06em;
}

/* === Robust Word Item Layout === */

.word-item {
  display: flex;
  flex-direction: column;        /* stack content + stats vertically */
  width: 100%;
  max-width: 100%;
  background-color: var(--color-surface);
  border: 1px solid var(--color-text-muted);
  border-left-width: 4px;
  border-radius: var(--border-radius-sm);
  padding: 0;                    /* padding moved to children */
  transition: border-color var(--transition-fast), 
              box-shadow var(--transition-fast);
  cursor: pointer;
}

.word-item:active {
  transform: scale(0.985);
}

.word-item.expanded {
  border-color: var(--color-accent);
  box-shadow: 0 0 12px var(--color-accent);
}

/* Top content row (Hangul + English + meta) */
.word-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  padding: var(--space-sm) var(--space-md);
  width: 100%;
}

/* Stats panel always sits below as full-width block */
.word-stats {
  width: 100%;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  background-color: var(--color-surface);
  border-top: 1px solid var(--color-text-muted);
  font-family: var(--font-display);
  box-sizing: border-box;
}

/* Stats grid cells */
.stat {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 42px;
}

.stat-label {
  font-size: 7px;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  line-height: 1;
  margin-bottom: 2px;
}

.stat-value {
  font-size: var(--font-size-md);
  color: var(--color-accent);
  line-height: 1;
  text-shadow: 0 0 4px var(--color-accent);
}

/* Locked state */
.word-item.locked {
  cursor: default;
  pointer-events: none;
  opacity: 0.45;
}

/* Strength % fade when expanded */
.word-item .accuracy.strength {
  color: var(--color-accent);
  font-weight: 400;
  transition: opacity var(--transition-speed) ease;
}

.word-item.expanded .accuracy.strength {
  opacity: 0;
}
/* master-deck.css — appended at end */
.word-stats .edit-custom-btn {
  grid-column: 1 / -1;   /* full-width row below the 6 stat cells */
  width: 100%;
  margin-top: var(--space-sm);
  box-sizing: border-box;
}