/* =========================================================================
   Voltlingo — Master Stylesheet
   Design language: Dark / Charcoal Black background, Neon Blue + Electric
   Yellow accents, minimalist, mobile-first, smooth transitions.
   ========================================================================= */

/* ---- Design tokens ------------------------------------------------------- */

:root {
  /* Surfaces */
  --color-bg:            #06070A;
  --color-surface:       #0E1116;
  --color-surface-2:     #151A22;
  --color-surface-3:     #1C2230;
  --color-border:        #232A38;

  /* Text */
  --color-text:          #F2F4F8;
  --color-text-muted:    #8A93A6;
  --color-text-dim:      #5A6478;

  /* Accents */
  --color-neon-blue:     #00E0FF;
  --color-neon-blue-soft:#1FB4D4;
  --color-electric:      #FFEC3D;
  --color-electric-soft: #D8C300;
  --color-danger:        #FF3B6B;
  --color-success:       #2DE08D;

  /* Glows */
  --glow-blue:           0 0 18px rgba(0, 224, 255, 0.45),
                         0 0 38px rgba(0, 224, 255, 0.18);
  --glow-yellow:         0 0 18px rgba(255, 236, 61, 0.45),
                         0 0 38px rgba(255, 236, 61, 0.18);

  /* Sizing */
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 22px;
  --radius-pill: 999px;

  /* Layout */
  --header-h: 64px;
  --nav-h:    72px;

  /* Motion */
  --ease-out: cubic-bezier(0.22, 1, 0.36, 1);
  --t-fast:   140ms;
  --t-base:   220ms;
  --t-slow:   420ms;

  /* Typography */
  --font-stack: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen,
                Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;
}

/* ---- Reset --------------------------------------------------------------- */

*, *::before, *::after { box-sizing: border-box; }

/*
 * Author rules (e.g. `.learn__lock { display: flex }`) outrank the UA
 * stylesheet's `[hidden] { display: none }`. Reassert the attribute globally
 * so any element with `hidden` actually disappears.
 */
[hidden] { display: none !important; }

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-stack);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow: hidden;
  overscroll-behavior: none;
}

button {
  font-family: inherit;
  font-size: inherit;
  color: inherit;
  background: none;
  border: none;
  padding: 0;
  cursor: pointer;
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.5;
}

ul { list-style: none; padding: 0; margin: 0; }

/* ---- App shell ----------------------------------------------------------- */

.app {
  display: grid;
  grid-template-rows: var(--header-h) 1fr var(--nav-h);
  height: 100dvh;
  width: 100%;
  max-width: 560px;
  margin: 0 auto;
  position: relative;
  background:
    radial-gradient(1200px 600px at 50% -10%,
      rgba(0, 224, 255, 0.08), transparent 60%),
    radial-gradient(800px 500px at 110% 110%,
      rgba(255, 236, 61, 0.06), transparent 60%),
    var(--color-bg);
}

/* ---- Header HUD ---------------------------------------------------------- */

.hud {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 18px;
  border-bottom: 1px solid var(--color-border);
  background: rgba(6, 7, 10, 0.85);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  z-index: 5;
}

.hud__brand {
  font-weight: 800;
  letter-spacing: 0.04em;
  font-size: 18px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.hud__brand-mark {
  color: var(--color-electric);
  text-shadow: var(--glow-yellow);
  font-size: 20px;
}

.hud__brand-name {
  background: linear-gradient(90deg, #FFFFFF 0%, var(--color-neon-blue) 100%);
  -webkit-background-clip: text;
          background-clip: text;
  color: transparent;
}

.hud__pro {
  margin-left: 8px;
  font-size: 10px;
  letter-spacing: 0.12em;
  padding: 2px 8px;
  border-radius: var(--radius-pill);
  background: var(--color-electric);
  color: #1a1300;
  font-weight: 800;
  text-shadow: none;
}

.hud__stats {
  display: flex;
  gap: 14px;
  align-items: center;
}

.hud__stat {
  display: flex;
  align-items: center;
  gap: 6px;
  font-weight: 700;
  font-size: 14px;
  padding: 6px 10px;
  border-radius: var(--radius-pill);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  transition: transform var(--t-fast) var(--ease-out),
              box-shadow var(--t-base) var(--ease-out);
}

.hud__stat-icon {
  font-size: 14px;
  line-height: 1;
}

.hud__stat--hearts .hud__stat-icon { color: var(--color-danger); }
.hud__stat--xp     .hud__stat-icon { color: var(--color-neon-blue); }
.hud__stat--streak .hud__stat-icon { color: var(--color-electric); }

.hud__stat-value {
  font-variant-numeric: tabular-nums;
  min-width: 18px;
  text-align: right;
  transition: color var(--t-base) var(--ease-out);
}

.hud__stat-value.is-low   { color: var(--color-danger); }
.hud__stat-value.is-infinite {
  color: var(--color-electric);
  text-shadow: var(--glow-yellow);
}

/* Live countdown to the next heart regen — only visible when hearts <
 * MAX_HEARTS and the user isn't on PRO. */
.hud__stat-timer {
  margin-left: 4px;
  padding-left: 6px;
  border-left: 1px solid var(--color-border);
  font-size: 10px;
  color: var(--color-text-muted);
  font-variant-numeric: tabular-nums;
  font-weight: 700;
  letter-spacing: 0.04em;
}

/* ---- Main / Screens ------------------------------------------------------ */

.main {
  position: relative;
  overflow: hidden;
}

.screen {
  position: absolute;
  inset: 0;
  padding: 18px;
  overflow-y: auto;
  opacity: 0;
  transform: translateY(8px);
  pointer-events: none;
  transition: opacity var(--t-base) var(--ease-out),
              transform var(--t-base) var(--ease-out);
}

.screen.is-active {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}

.screen__title {
  margin: 4px 0 16px;
  font-size: 22px;
  font-weight: 800;
  letter-spacing: 0.02em;
}

.screen__subtitle {
  margin: 0 0 18px;
  font-size: 13px;
  color: var(--color-text-muted);
}

/* ---- Learn / Sub-views --------------------------------------------------- */

/*
 * The learn screen is a stack of three sub-views (categories → units → quiz).
 * Override the .screen defaults so each .learn-view manages its own padding
 * and scroll independently.
 */
.screen.learn {
  padding: 0;
  overflow: hidden;
}

.learn-view {
  position: absolute;
  inset: 0;
  padding: 18px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 12px;
  opacity: 0;
  pointer-events: none;
  transform: translateY(6px);
  transition: opacity var(--t-base) var(--ease-out),
              transform var(--t-base) var(--ease-out);
}

.learn-view.is-active {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}

/* ---- Back button --------------------------------------------------------- */

.back-btn {
  align-self: flex-start;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  margin-bottom: 4px;
  border-radius: var(--radius-pill);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--color-text-muted);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  transition: color var(--t-base) var(--ease-out),
              border-color var(--t-base) var(--ease-out),
              transform var(--t-fast) var(--ease-out);
}

.back-btn:hover {
  color: var(--color-neon-blue);
  border-color: var(--color-neon-blue);
}

.back-btn:active {
  transform: scale(0.97);
}

/* ---- Category list ------------------------------------------------------- */

.category-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 8px;
}

.category-row {
  display: grid;
  grid-template-columns: 56px 1fr 24px;
  align-items: center;
  gap: 14px;
  padding: 16px;
  width: 100%;
  border-radius: var(--radius-lg);
  background: linear-gradient(160deg,
              var(--color-surface) 0%,
              var(--color-surface-2) 100%);
  border: 1px solid var(--color-border);
  text-align: left;
  transition: transform var(--t-fast) var(--ease-out),
              border-color var(--t-base) var(--ease-out),
              box-shadow var(--t-base) var(--ease-out);
}

.category-row:hover {
  transform: translateX(2px);
  border-color: var(--color-neon-blue);
  box-shadow: var(--glow-blue);
}

.category-row:active {
  transform: scale(0.99);
}

.category-row__icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  display: grid;
  place-items: center;
  font-size: 24px;
  font-weight: 800;
  background: var(--color-surface-3);
  color: var(--color-text);
}

.category-row--blue   .category-row__icon { color: var(--color-neon-blue); text-shadow: var(--glow-blue); }
.category-row--yellow .category-row__icon { color: var(--color-electric);  text-shadow: var(--glow-yellow); }
.category-row--mint   .category-row__icon { color: var(--color-success);   text-shadow: 0 0 18px rgba(45, 224, 141, 0.40); }
.category-row--pink   .category-row__icon { color: var(--color-danger);    text-shadow: 0 0 18px rgba(255, 59, 107, 0.40); }

.category-row__body {
  display: flex;
  flex-direction: column;
  gap: 3px;
  min-width: 0;
}

.category-row__name {
  font-weight: 800;
  font-size: 16px;
  color: var(--color-text);
}

.category-row__tagline {
  font-size: 12px;
  color: var(--color-text-muted);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.category-row__meta {
  margin-top: 2px;
  font-size: 11px;
  color: var(--color-text-dim);
  letter-spacing: 0.04em;
}

.category-row__chevron {
  color: var(--color-text-dim);
  font-size: 22px;
  line-height: 1;
}

/* ---- Daily Quest (today's XP ring on Categories) ----------------------- */

.daily-quest {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 12px 16px;
  border-radius: var(--radius-lg);
  background: linear-gradient(160deg,
              var(--color-surface) 0%,
              var(--color-surface-2) 100%);
  border: 1px solid var(--color-border);
  margin-bottom: 8px;
  transition: border-color var(--t-base) var(--ease-out),
              box-shadow var(--t-base) var(--ease-out);
}

.daily-quest.is-complete {
  border-color: var(--color-electric);
  box-shadow: var(--glow-yellow);
}

.daily-quest__ring {
  position: relative;
  width: 48px;
  height: 48px;
  flex-shrink: 0;
}

.daily-quest__svg {
  width: 100%;
  height: 100%;
  transform: rotate(-90deg);
}

.daily-quest__bg {
  fill: none;
  stroke: var(--color-surface-3);
  stroke-width: 3;
}

.daily-quest__fill {
  fill: none;
  stroke: var(--color-neon-blue);
  stroke-width: 3;
  stroke-linecap: round;
  transition: stroke-dashoffset 600ms var(--ease-out),
              stroke var(--t-base) var(--ease-out);
  filter: drop-shadow(0 0 6px rgba(0, 224, 255, 0.45));
}

.daily-quest.is-complete .daily-quest__fill {
  stroke: var(--color-electric);
  filter: drop-shadow(0 0 6px rgba(255, 236, 61, 0.55));
}

.daily-quest__icon {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  font-size: 18px;
  color: var(--color-neon-blue);
  transition: color var(--t-base) var(--ease-out),
              text-shadow var(--t-base) var(--ease-out);
}

.daily-quest.is-complete .daily-quest__icon {
  color: var(--color-electric);
  text-shadow: var(--glow-yellow);
}

.daily-quest__body {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
  flex: 1;
}

.daily-quest__label {
  font-size: 10px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  font-weight: 700;
}

.daily-quest__progress {
  font-size: 14px;
  color: var(--color-text);
  font-variant-numeric: tabular-nums;
}

.daily-quest__progress strong {
  color: var(--color-neon-blue);
  font-weight: 800;
  transition: color var(--t-base) var(--ease-out);
}

.daily-quest.is-complete .daily-quest__progress strong {
  color: var(--color-electric);
}

.daily-quest__check {
  font-size: 26px;
  font-weight: 800;
  color: var(--color-electric);
  text-shadow: var(--glow-yellow);
  flex-shrink: 0;
}

/* ---- Unit list ----------------------------------------------------------- */

.unit-list__header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin: 4px 0;
}

.unit-list__accent {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  background: var(--color-surface-3);
  display: grid;
  place-items: center;
  font-size: 22px;
  font-weight: 800;
  flex-shrink: 0;
}

.unit-list__accent--blue   { color: var(--color-neon-blue); text-shadow: var(--glow-blue); }
.unit-list__accent--yellow { color: var(--color-electric);  text-shadow: var(--glow-yellow); }
.unit-list__accent--mint   { color: var(--color-success);   text-shadow: 0 0 18px rgba(45, 224, 141, 0.40); }
.unit-list__accent--pink   { color: var(--color-danger);    text-shadow: 0 0 18px rgba(255, 59, 107, 0.40); }

.unit-list__heading .screen__title { margin: 0; }
.unit-list__heading .screen__subtitle { margin: 2px 0 0; }

.unit-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-top: 6px;
}

.unit-row {
  display: grid;
  grid-template-columns: 36px 1fr auto;
  align-items: center;
  gap: 12px;
  padding: 14px;
  width: 100%;
  border-radius: var(--radius-md);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  text-align: left;
  transition: transform var(--t-fast) var(--ease-out),
              border-color var(--t-base) var(--ease-out),
              box-shadow var(--t-base) var(--ease-out),
              opacity var(--t-base) var(--ease-out);
}

.unit-row:hover { transform: translateX(2px); }
.unit-row:active { transform: scale(0.99); }

.unit-row--free:hover {
  border-color: var(--color-neon-blue);
  box-shadow: var(--glow-blue);
}

.unit-row--locked {
  opacity: 0.78;
}

.unit-row--locked:hover {
  opacity: 1;
  border-color: var(--color-electric);
}

.unit-row__index {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  font-weight: 800;
  font-size: 13px;
  background: var(--color-surface-3);
  color: var(--color-text-muted);
}

.unit-row--free .unit-row__index {
  background: var(--color-neon-blue);
  color: #001318;
  box-shadow: var(--glow-blue);
}

/* PRO-unlocked unit: same energy as the free demo, but in electric yellow
 * so the user feels the upgrade every time they look at a sector list. */
.unit-row--unlocked:hover {
  border-color: var(--color-electric);
  box-shadow: var(--glow-yellow);
}

.unit-row--unlocked .unit-row__index {
  background: var(--color-electric);
  color: #1a1300;
  box-shadow: var(--glow-yellow);
}

.unit-row__badge--pro {
  background: var(--color-electric);
  color: #1a1300;
}

.unit-row__body {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
}

.unit-row__name {
  font-weight: 700;
  font-size: 14px;
  color: var(--color-text);
}

.unit-row__meta {
  font-size: 11px;
  color: var(--color-text-muted);
}

.unit-row__status {
  display: flex;
  align-items: center;
}

.unit-row__badge {
  font-size: 10px;
  letter-spacing: 0.16em;
  padding: 4px 10px;
  border-radius: var(--radius-pill);
  background: var(--color-neon-blue);
  color: #001318;
  font-weight: 800;
}

.unit-row__lock {
  font-size: 18px;
  color: var(--color-electric);
  text-shadow: var(--glow-yellow);
}

/* ---- Ad slot (Google AdSense / AdMob placeholder) ----------------------- */

.ad-slot {
  position: relative;
  width: 100%;
  min-height: 72px;
  margin-top: 10px;
  padding: 14px;
  border: 1px dashed var(--color-border);
  border-radius: var(--radius-md);
  background:
    repeating-linear-gradient(
      45deg,
      transparent 0,
      transparent 8px,
      rgba(255, 255, 255, 0.015) 8px,
      rgba(255, 255, 255, 0.015) 16px
    ),
    var(--color-surface);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.ad-slot__label {
  position: absolute;
  top: -9px;
  left: 14px;
  padding: 2px 10px;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-pill);
  font-size: 9px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--color-text-muted);
}

.ad-slot__inner {
  width: 100%;
  text-align: center;
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--color-text-dim);
}

.ad-slot--banner {
  min-height: 82px;
}

/* ---- Auth modal (Firebase Auth gate) ------------------------------------ */

.auth-modal {
  position: fixed;
  inset: 0;
  z-index: 60;
  background: rgba(6, 7, 10, 0.78);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  display: grid;
  place-items: center;
  padding: 22px;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--t-base) var(--ease-out);
}

.auth-modal.is-open {
  opacity: 1;
  pointer-events: auto;
}

.auth-modal__dialog {
  width: 100%;
  max-width: 420px;
  padding: 26px 24px 22px;
  background: linear-gradient(160deg,
              var(--color-surface) 0%,
              var(--color-surface-2) 100%);
  border: 1px solid var(--color-neon-blue);
  border-radius: var(--radius-lg);
  box-shadow:
    0 30px 80px rgba(0, 0, 0, 0.6),
    var(--glow-blue);
  transform: translateY(14px) scale(0.98);
  transition: transform var(--t-base) var(--ease-out);
}

.auth-modal.is-open .auth-modal__dialog {
  transform: translateY(0) scale(1);
}

.auth-modal__close {
  position: absolute;
  top: 28px;
  right: 28px;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--color-surface-3);
  color: var(--color-text-muted);
  display: grid;
  place-items: center;
  font-size: 16px;
  transition: background-color var(--t-fast) var(--ease-out),
              color var(--t-fast) var(--ease-out);
}

.auth-modal__close:hover {
  background: var(--color-surface-2);
  color: var(--color-text);
}

.auth-modal__icon {
  font-size: 36px;
  text-align: center;
  margin-bottom: 8px;
  color: var(--color-electric);
  text-shadow: var(--glow-yellow);
}

.auth-modal__title {
  margin: 0 0 8px;
  text-align: center;
  font-size: 22px;
  font-weight: 800;
}

.auth-modal__desc {
  margin: 0 0 20px;
  text-align: center;
  font-size: 13px;
  line-height: 1.55;
  color: var(--color-text-muted);
}

.auth-modal__actions {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.auth-btn {
  height: 48px;
  border-radius: var(--radius-md);
  font-weight: 700;
  font-size: 14px;
  letter-spacing: 0.02em;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  border: 1px solid transparent;
  transition: transform var(--t-fast) var(--ease-out),
              background-color var(--t-base) var(--ease-out),
              box-shadow var(--t-base) var(--ease-out);
}

.auth-btn:active {
  transform: scale(0.98);
}

.auth-btn__icon {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: #FFFFFF;
  color: #4285F4;
  font-weight: 800;
  display: grid;
  place-items: center;
  font-size: 13px;
}

.auth-btn--google {
  background: var(--color-text);
  color: #1a1a1a;
}
.auth-btn--google:hover { background: #FFFFFF; }

.auth-btn--email {
  background: var(--color-neon-blue);
  color: #001318;
  box-shadow: var(--glow-blue);
}
.auth-btn--email:hover { background: #2BEBFF; }

.auth-btn--ghost {
  background: transparent;
  color: var(--color-text-muted);
  border-color: var(--color-border);
}
.auth-btn--ghost:hover {
  color: var(--color-text);
  border-color: var(--color-text-muted);
}

.auth-modal__footnote {
  margin: 14px 0 0;
  font-size: 11px;
  text-align: center;
  color: var(--color-text-dim);
}

/* =========================================================================
   Quiz Engine (replaces the old flashcard view)
   ========================================================================= */

.learn-view--quiz {
  gap: 12px;
}

/* Topbar holds the back button + progress, layered above the lock overlay
 * so the user can always escape to the units list. */
.quiz__topbar {
  display: flex;
  align-items: center;
  gap: 12px;
  position: relative;
  z-index: 5;
}

.quiz__topbar .back-btn {
  margin-bottom: 0;
  flex-shrink: 0;
}

.quiz__progress {
  flex: 1 1 auto;
  display: flex;
  align-items: center;
  gap: 10px;
}

.quiz__progress-bar {
  flex: 1 1 auto;
  height: 8px;
  background: var(--color-surface-3);
  border-radius: var(--radius-pill);
  overflow: hidden;
}

.quiz__progress-fill {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg,
              var(--color-neon-blue) 0%,
              var(--color-electric) 100%);
  border-radius: var(--radius-pill);
  transition: width 360ms var(--ease-out);
  box-shadow: 0 0 12px rgba(0, 224, 255, 0.45);
}

.quiz__count {
  font-size: 11px;
  font-weight: 800;
  color: var(--color-text-muted);
  font-variant-numeric: tabular-nums;
  min-width: 42px;
  text-align: right;
  letter-spacing: 0.04em;
}

.quiz__deck {
  margin: 0;
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--color-neon-blue);
  text-align: center;
}

/* Combo chip — surfaces only when the in-round streak hits the first
 * multiplier tier (combo ≥ 3). Pops on every bump for dopamine. */
.quiz__meta {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
}

.quiz__combo {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 3px 12px;
  border-radius: var(--radius-pill);
  background: linear-gradient(90deg,
              rgba(255, 140, 0, 0.18) 0%,
              rgba(255, 236, 61, 0.22) 100%);
  border: 1px solid var(--color-electric);
  color: var(--color-electric);
  font-size: 10px;
  font-weight: 800;
  letter-spacing: 0.10em;
  text-transform: uppercase;
  text-shadow: 0 0 12px rgba(255, 236, 61, 0.5);
}

.quiz__combo.is-pop {
  animation: combo-pop 360ms var(--ease-out);
}

@keyframes combo-pop {
  0%   { transform: scale(0.5); opacity: 0.4; }
  55%  { transform: scale(1.2); opacity: 1;   }
  100% { transform: scale(1);                 }
}

.quiz__prompt {
  margin: 0;
  font-size: 17px;
  font-weight: 800;
  color: var(--color-text);
  text-align: center;
  line-height: 1.35;
}

.quiz__stage {
  flex: 1 1 auto;
  display: flex;
  flex-direction: column;
  gap: 12px;
  min-height: 0;
}

/* ---- Multiple Choice ---------------------------------------------------- */

.quiz-mc {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.quiz-mc__definition {
  padding: 22px 20px;
  background: linear-gradient(160deg,
              var(--color-surface) 0%,
              var(--color-surface-2) 100%);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  font-size: 17px;
  line-height: 1.5;
  color: var(--color-text);
  text-align: center;
  font-weight: 600;
  box-shadow: var(--glow-blue);
}

.quiz-mc__options {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.quiz-option {
  padding: 18px 14px;
  border-radius: var(--radius-md);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  color: var(--color-text);
  font-weight: 700;
  font-size: 14px;
  text-align: center;
  transition: transform var(--t-fast) var(--ease-out),
              border-color var(--t-base) var(--ease-out),
              box-shadow var(--t-base) var(--ease-out),
              background-color var(--t-base) var(--ease-out),
              color var(--t-base) var(--ease-out);
}

.quiz-option:hover {
  transform: translateY(-2px);
  border-color: var(--color-neon-blue);
}
.quiz-option:active { transform: scale(0.98); }

.quiz-option.is-selected {
  border-color: var(--color-neon-blue);
  background: rgba(0, 224, 255, 0.12);
  box-shadow: var(--glow-blue);
}

.quiz-option.is-correct {
  border-color: var(--color-success);
  background: rgba(45, 224, 141, 0.18);
  color: var(--color-success);
  box-shadow: 0 0 18px rgba(45, 224, 141, 0.30);
}

.quiz-option.is-wrong {
  border-color: var(--color-danger);
  background: rgba(255, 59, 107, 0.14);
  color: var(--color-danger);
  animation: quiz-shake 0.4s ease-in-out;
}

@keyframes quiz-shake {
  0%, 100% { transform: translateX(0); }
  20%, 60% { transform: translateX(-6px); }
  40%, 80% { transform: translateX(6px); }
}

/* ---- Fill in the Blank -------------------------------------------------- */

.quiz-fib {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.quiz-fib__sentence {
  padding: 22px 20px;
  background: linear-gradient(160deg,
              var(--color-surface) 0%,
              var(--color-surface-2) 100%);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text);
  text-align: center;
  font-weight: 500;
  box-shadow: var(--glow-blue);
}

.quiz-fib__pool {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.quiz-chip {
  padding: 14px 12px;
  border-radius: var(--radius-pill);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  color: var(--color-text);
  font-weight: 700;
  font-size: 14px;
  text-align: center;
  transition: transform var(--t-fast) var(--ease-out),
              border-color var(--t-base) var(--ease-out),
              box-shadow var(--t-base) var(--ease-out),
              background-color var(--t-base) var(--ease-out),
              color var(--t-base) var(--ease-out);
}

.quiz-chip:hover {
  transform: translateY(-2px);
  border-color: var(--color-electric);
}
.quiz-chip:active { transform: scale(0.98); }

.quiz-chip.is-selected {
  border-color: var(--color-electric);
  background: rgba(255, 236, 61, 0.12);
  color: var(--color-electric);
  box-shadow: var(--glow-yellow);
}

.quiz-chip.is-correct {
  border-color: var(--color-success);
  background: rgba(45, 224, 141, 0.18);
  color: var(--color-success);
}

.quiz-chip.is-wrong {
  border-color: var(--color-danger);
  background: rgba(255, 59, 107, 0.14);
  color: var(--color-danger);
  animation: quiz-shake 0.4s ease-in-out;
}

/* ---- Word Matching ------------------------------------------------------ */

.quiz-match {
  display: grid;
  grid-template-columns: minmax(110px, 1fr) 1.6fr;
  gap: 10px;
}

.quiz-match__col {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.quiz-match-item {
  padding: 14px 12px;
  border-radius: var(--radius-md);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  color: var(--color-text);
  font-weight: 700;
  font-size: 13px;
  text-align: left;
  line-height: 1.35;
  flex: 1;
  display: flex;
  align-items: center;
  transition: transform var(--t-fast) var(--ease-out),
              border-color var(--t-base) var(--ease-out),
              box-shadow var(--t-base) var(--ease-out),
              opacity var(--t-base) var(--ease-out),
              background-color var(--t-base) var(--ease-out),
              color var(--t-base) var(--ease-out);
}

.quiz-match__col--terms .quiz-match-item {
  justify-content: center;
  text-align: center;
}

.quiz-match-item:hover {
  border-color: var(--color-neon-blue);
}

.quiz-match-item:active { transform: scale(0.98); }

.quiz-match-item.is-selected {
  border-color: var(--color-neon-blue);
  background: rgba(0, 224, 255, 0.14);
  color: var(--color-neon-blue);
  box-shadow: var(--glow-blue);
}

.quiz-match-item.is-correct {
  border-color: var(--color-success);
  background: rgba(45, 224, 141, 0.18);
  color: var(--color-success);
  box-shadow: 0 0 16px rgba(45, 224, 141, 0.30);
}

.quiz-match-item.is-wrong {
  animation: quiz-shake 0.4s ease-in-out;
  border-color: var(--color-danger);
  background: rgba(255, 59, 107, 0.12);
  color: var(--color-danger);
}

.quiz-match-item.is-resolved {
  opacity: 0.55;
  pointer-events: none;
}

/* ---- Symbol Identification ---------------------------------------------- */

.quiz-symbol {
  display: flex;
  flex-direction: column;
  gap: 16px;
  align-items: center;
}

.quiz-symbol__icon {
  width: 100%;
  max-width: 280px;
  padding: 22px 26px;
  background: linear-gradient(160deg,
              var(--color-surface) 0%,
              var(--color-surface-2) 100%);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--glow-blue);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-neon-blue);
}

.quiz-symbol__icon svg {
  width: 100%;
  height: auto;
  display: block;
  filter: drop-shadow(0 0 8px rgba(0, 224, 255, 0.55));
}

.quiz-symbol__options {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  width: 100%;
}

/* ---- Listen (TTS) ------------------------------------------------------- */

.quiz-listen {
  display: flex;
  flex-direction: column;
  gap: 18px;
  align-items: center;
}

.quiz-listen__play {
  width: 110px;
  height: 110px;
  border-radius: 50%;
  background: linear-gradient(160deg,
              var(--color-surface) 0%,
              var(--color-surface-2) 100%);
  border: 2px solid var(--color-neon-blue);
  color: var(--color-neon-blue);
  display: grid;
  place-items: center;
  box-shadow: var(--glow-blue);
  transition: transform var(--t-fast) var(--ease-out),
              background-color var(--t-base) var(--ease-out),
              box-shadow var(--t-base) var(--ease-out);
}

.quiz-listen__play:hover { transform: scale(1.04); }
.quiz-listen__play:active { transform: scale(0.97); }

.quiz-listen__play svg {
  width: 44px;
  height: 44px;
}

.quiz-listen__play.is-playing {
  animation: pulse-listen 1.4s ease-in-out infinite;
}

@keyframes pulse-listen {
  0%, 100% { box-shadow: 0 0 0 0   rgba(0, 224, 255, 0.55), var(--glow-blue); }
  50%      { box-shadow: 0 0 0 18px rgba(0, 224, 255, 0),    var(--glow-blue); }
}

.quiz-listen__pool {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  width: 100%;
}

/* ---- Speak (STT) -------------------------------------------------------- */

.quiz-speak {
  display: flex;
  flex-direction: column;
  gap: 14px;
  align-items: center;
}

.quiz-speak__term-card {
  width: 100%;
  padding: 22px 20px;
  background: linear-gradient(160deg,
              var(--color-surface) 0%,
              var(--color-surface-2) 100%);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  box-shadow: var(--glow-yellow);
  transition: border-color var(--t-base) var(--ease-out),
              box-shadow var(--t-base) var(--ease-out);
}

.quiz-speak__term-card.is-correct {
  border-color: var(--color-success);
  box-shadow: 0 0 18px rgba(45, 224, 141, 0.35);
}

.quiz-speak__term-card.is-wrong {
  border-color: var(--color-danger);
  box-shadow: 0 0 18px rgba(255, 59, 107, 0.35);
}

.quiz-speak__term {
  font-size: 28px;
  font-weight: 800;
  color: var(--color-electric);
  text-shadow: var(--glow-yellow);
  letter-spacing: 0.02em;
}

.quiz-speak__definition {
  margin: 0;
  font-size: 13px;
  color: var(--color-text-muted);
  text-align: center;
  line-height: 1.5;
}

.quiz-speak__hear {
  margin-top: 6px;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  border-radius: var(--radius-pill);
  background: var(--color-surface-3);
  border: 1px solid var(--color-border);
  color: var(--color-text-muted);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-weight: 700;
  transition: color var(--t-base) var(--ease-out),
              border-color var(--t-base) var(--ease-out);
}

.quiz-speak__hear:hover {
  color: var(--color-neon-blue);
  border-color: var(--color-neon-blue);
}

.quiz-speak__hear svg {
  width: 14px;
  height: 14px;
}

.quiz-speak__hear.is-playing {
  color: var(--color-neon-blue);
  border-color: var(--color-neon-blue);
}

.quiz-speak__mic {
  width: 92px;
  height: 92px;
  border-radius: 50%;
  background: linear-gradient(160deg,
              var(--color-surface) 0%,
              var(--color-surface-2) 100%);
  border: 2px solid var(--color-electric);
  color: var(--color-electric);
  display: grid;
  place-items: center;
  box-shadow: var(--glow-yellow);
  transition: transform var(--t-fast) var(--ease-out),
              border-color var(--t-base) var(--ease-out),
              color var(--t-base) var(--ease-out);
}

.quiz-speak__mic:hover { transform: scale(1.04); }
.quiz-speak__mic:active { transform: scale(0.97); }

.quiz-speak__mic svg {
  width: 36px;
  height: 36px;
}

.quiz-speak__mic.is-recording {
  border-color: var(--color-danger);
  color: var(--color-danger);
  animation: pulse-record 1.2s ease-in-out infinite;
}

.quiz-speak__mic.is-correct {
  border-color: var(--color-success);
  color: var(--color-success);
}

.quiz-speak__mic.is-wrong {
  border-color: var(--color-danger);
  color: var(--color-danger);
}

@keyframes pulse-record {
  0%, 100% { box-shadow: 0 0 0 0   rgba(255, 59, 107, 0.55); }
  50%      { box-shadow: 0 0 0 18px rgba(255, 59, 107, 0);    }
}

.quiz-speak__status {
  font-size: 13px;
  color: var(--color-text-muted);
  text-align: center;
  line-height: 1.4;
  max-width: 90%;
  min-height: 20px;
}

.quiz-speak__status.is-error { color: var(--color-danger); }
.quiz-speak__status.is-success { color: var(--color-success); }

/* ---- Quiz footer (feedback + action) ------------------------------------ */

.quiz__footer {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.quiz__feedback {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 14px;
  border-radius: var(--radius-md);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  font-size: 13px;
  line-height: 1.4;
}

.quiz__feedback.is-correct {
  border-color: var(--color-success);
  background: rgba(45, 224, 141, 0.10);
  color: var(--color-success);
}

.quiz__feedback.is-wrong {
  border-color: var(--color-danger);
  background: rgba(255, 59, 107, 0.10);
  color: var(--color-danger);
}

.quiz__feedback-icon {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  font-weight: 800;
  font-size: 14px;
  flex-shrink: 0;
}

.quiz__feedback.is-correct .quiz__feedback-icon {
  background: var(--color-success);
  color: #001813;
}

.quiz__feedback.is-wrong .quiz__feedback-icon {
  background: var(--color-danger);
  color: #1a0008;
}

.quiz__feedback-text {
  flex: 1;
  min-width: 0;
}

.quiz__action {
  height: 56px;
  border-radius: var(--radius-md);
  background: var(--color-neon-blue);
  color: #001318;
  font-weight: 800;
  font-size: 15px;
  letter-spacing: 0.04em;
  box-shadow: var(--glow-blue);
  transition: transform var(--t-fast) var(--ease-out),
              background-color var(--t-base) var(--ease-out),
              box-shadow var(--t-base) var(--ease-out);
}

.quiz__action:hover { background: #2BEBFF; }
.quiz__action:active { transform: scale(0.98); }

.quiz__action[data-state="continue"] {
  background: var(--color-electric);
  color: #1a1300;
  box-shadow: var(--glow-yellow);
}

.quiz__action[data-state="continue"]:hover { background: #FFF36E; }

/* ---- Lesson complete overlay -------------------------------------------- */

.quiz-complete {
  position: absolute;
  inset: 0;
  z-index: 6;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 18px;
  padding: 28px;
  background: rgba(6, 7, 10, 0.94);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  opacity: 0;
  transition: opacity var(--t-base) var(--ease-out);
}

.quiz-complete.is-open { opacity: 1; }

.quiz-complete__icon {
  font-size: 56px;
  color: var(--color-electric);
  text-shadow: var(--glow-yellow);
}

.quiz-complete__title {
  margin: 0;
  font-size: 26px;
  font-weight: 800;
  text-align: center;
  color: var(--color-text);
}

.quiz-complete__stats {
  display: flex;
  gap: 12px;
}

.stat-pill {
  padding: 14px 18px;
  border-radius: var(--radius-md);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  min-width: 116px;
}

.stat-pill__label {
  font-size: 10px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  font-weight: 700;
}

.stat-pill__value {
  font-size: 22px;
  font-weight: 800;
  color: var(--color-neon-blue);
  font-variant-numeric: tabular-nums;
}

.quiz-complete__btn {
  margin-top: 4px;
  height: 54px;
  padding: 0 36px;
  border-radius: var(--radius-pill);
  background: var(--color-electric);
  color: #1a1300;
  font-weight: 800;
  font-size: 15px;
  letter-spacing: 0.04em;
  box-shadow: var(--glow-yellow);
  transition: transform var(--t-fast) var(--ease-out),
              background-color var(--t-base) var(--ease-out);
}

.quiz-complete__btn:hover { background: #FFF36E; }
.quiz-complete__btn:active { transform: scale(0.98); }

/* ---- Lock overlay (hearts ran out) -------------------------------------- */

.learn__lock {
  position: absolute;
  inset: 0;
  z-index: 4;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  background: rgba(6, 7, 10, 0.78);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  text-align: center;
  padding: 24px;
}

.learn__lock-icon {
  font-size: 42px;
  color: var(--color-danger);
  text-shadow: 0 0 28px rgba(255, 59, 107, 0.55);
}

.learn__lock-title {
  font-size: 22px;
  font-weight: 800;
  margin: 0;
}

.learn__lock-desc {
  font-size: 14px;
  color: var(--color-text-muted);
  max-width: 320px;
  margin: 0;
}

/* ---- Leaderboard --------------------------------------------------------- */

.leaderboard__list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.leaderboard__row {
  display: grid;
  grid-template-columns: 36px 1fr auto auto;
  align-items: center;
  gap: 12px;
  padding: 12px 14px;
  border-radius: var(--radius-md);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  transition: transform var(--t-base) var(--ease-out),
              border-color var(--t-base) var(--ease-out);
}

.leaderboard__row:hover { transform: translateX(2px); }

.leaderboard__row--self {
  border-color: var(--color-neon-blue);
  background: linear-gradient(90deg,
              rgba(0, 224, 255, 0.12) 0%,
              var(--color-surface) 100%);
  box-shadow: var(--glow-blue);
}

.leaderboard__rank {
  width: 28px; height: 28px;
  border-radius: 50%;
  display: grid; place-items: center;
  font-weight: 800;
  font-size: 13px;
  background: var(--color-surface-3);
  color: var(--color-text-muted);
}

.leaderboard__rank.medal {
  color: #1a1300;
}
.leaderboard__rank.medal--1 { background: var(--color-electric); box-shadow: var(--glow-yellow); }
.leaderboard__rank.medal--2 { background: #C0C8D6; }
.leaderboard__rank.medal--3 { background: #CD7F32; color: #FFF; }

.leaderboard__name {
  font-weight: 700;
  font-size: 14px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.leaderboard__flag {
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--color-text-muted);
  padding: 2px 6px;
  background: var(--color-surface-3);
  border-radius: 4px;
}

.leaderboard__xp {
  font-variant-numeric: tabular-nums;
  font-weight: 800;
  font-size: 13px;
  color: var(--color-neon-blue);
}

/* ---- Achievements (badge grid + toast) ---------------------------------- */

.leaderboard__section-title {
  margin: 22px 0 10px;
  font-size: 13px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  font-weight: 700;
}

.achievement-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
}

.achievement-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  padding: 14px 8px;
  border-radius: var(--radius-md);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  text-align: center;
  transition: transform var(--t-fast) var(--ease-out),
              border-color var(--t-base) var(--ease-out),
              box-shadow var(--t-base) var(--ease-out),
              opacity var(--t-base) var(--ease-out);
}

.achievement-card--unlocked {
  border-color: var(--color-electric);
  box-shadow: var(--glow-yellow);
}

.achievement-card--unlocked:hover {
  transform: translateY(-2px);
}

.achievement-card--locked {
  opacity: 0.45;
}

.achievement-card__icon {
  font-size: 28px;
  line-height: 1;
}

.achievement-card--unlocked .achievement-card__icon {
  text-shadow: var(--glow-yellow);
}

.achievement-card--locked .achievement-card__icon {
  filter: grayscale(1);
}

.achievement-card__title {
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.04em;
  color: var(--color-text);
  line-height: 1.2;
}

.achievement-card__desc {
  font-size: 9px;
  color: var(--color-text-muted);
  letter-spacing: 0.02em;
  line-height: 1.3;
}

.achievement-toast {
  position: fixed;
  top: 78px;
  left: 50%;
  transform: translateX(-50%) translateY(-24px);
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 12px 18px;
  border-radius: var(--radius-md);
  background: linear-gradient(160deg,
              var(--color-surface-2) 0%,
              var(--color-surface-3) 100%);
  border: 1px solid var(--color-electric);
  box-shadow:
    0 20px 50px rgba(0, 0, 0, 0.6),
    var(--glow-yellow);
  z-index: 70;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--t-base) var(--ease-out),
              transform var(--t-base) var(--ease-out);
  min-width: 260px;
  max-width: 92vw;
}

.achievement-toast.is-visible {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

.achievement-toast__icon {
  font-size: 30px;
  line-height: 1;
  flex-shrink: 0;
  color: var(--color-electric);
  text-shadow: var(--glow-yellow);
}

.achievement-toast__body {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
}

.achievement-toast__label {
  font-size: 9px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--color-text-dim);
  font-weight: 700;
}

.achievement-toast__name {
  font-size: 15px;
  font-weight: 800;
  color: var(--color-text);
}

.achievement-toast__desc {
  font-size: 11px;
  color: var(--color-text-muted);
}

/* ---- Shop ---------------------------------------------------------------- */

.shop {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.shop-card {
  position: relative;
  padding: 20px;
  border-radius: var(--radius-lg);
  background: linear-gradient(160deg,
              var(--color-surface) 0%,
              var(--color-surface-2) 100%);
  border: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  gap: 14px;
  overflow: hidden;
}

.shop-card__title {
  margin: 0;
  font-size: 18px;
  font-weight: 800;
}

.shop-card__desc {
  margin: 0;
  font-size: 13px;
  line-height: 1.55;
  color: var(--color-text-muted);
}

.shop-card__price {
  font-size: 13px;
  color: var(--color-text-dim);
  letter-spacing: 0.06em;
}

.shop-card__price strong {
  color: var(--color-text);
  font-weight: 800;
  font-size: 18px;
}

.shop-btn {
  align-self: flex-start;
  padding: 12px 22px;
  border-radius: var(--radius-pill);
  font-weight: 800;
  letter-spacing: 0.04em;
  transition: transform var(--t-fast) var(--ease-out),
              box-shadow var(--t-base) var(--ease-out);
}

.shop-btn:active { transform: scale(0.97); }

.shop-btn.is-flashing {
  animation: pulse var(--t-slow) var(--ease-out);
}

@keyframes pulse {
  0%   { transform: scale(1); }
  40%  { transform: scale(1.06); }
  100% { transform: scale(1); }
}

.shop-btn--blue {
  background: var(--color-neon-blue);
  color: #001318;
  box-shadow: var(--glow-blue);
}

.shop-btn--yellow {
  background: var(--color-electric);
  color: #1a1300;
  box-shadow: var(--glow-yellow);
}

/* PRO card flair */

.shop-card--pro {
  border-color: var(--color-electric);
  background:
    radial-gradient(800px 200px at 0% 0%, rgba(255, 236, 61, 0.10), transparent 60%),
    radial-gradient(600px 220px at 100% 100%, rgba(0, 224, 255, 0.10), transparent 60%),
    linear-gradient(160deg, var(--color-surface) 0%, var(--color-surface-2) 100%);
}

.shop-card__badge {
  position: absolute;
  top: 16px;
  right: 16px;
  font-size: 10px;
  letter-spacing: 0.18em;
  padding: 4px 10px;
  border-radius: var(--radius-pill);
  background: var(--color-electric);
  color: #1a1300;
  font-weight: 800;
}

.shop-card__perks {
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: 13px;
  color: var(--color-text);
}

.shop-card__perks li {
  display: flex;
  align-items: center;
  gap: 8px;
}

.shop-card__perks li::before {
  content: '⚡';
  color: var(--color-electric);
  text-shadow: var(--glow-yellow);
  font-size: 14px;
}

/* ---- Paywall overlay ----------------------------------------------------- */

.paywall {
  position: fixed;
  inset: 0;
  background: rgba(6, 7, 10, 0.78);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  display: grid;
  place-items: center;
  padding: 22px;
  z-index: 50;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--t-base) var(--ease-out);
}

.paywall.is-open {
  opacity: 1;
  pointer-events: auto;
}

.paywall__dialog {
  width: 100%;
  max-width: 420px;
  background: linear-gradient(160deg,
              var(--color-surface) 0%,
              var(--color-surface-2) 100%);
  border: 1px solid var(--color-electric);
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow:
    0 30px 80px rgba(0, 0, 0, 0.6),
    var(--glow-yellow);
  transform: translateY(14px) scale(0.98);
  transition: transform var(--t-base) var(--ease-out);
}

.paywall.is-open .paywall__dialog {
  transform: translateY(0) scale(1);
}

.paywall__icon {
  font-size: 36px;
  color: var(--color-danger);
  text-shadow: 0 0 24px rgba(255, 59, 107, 0.55);
  text-align: center;
  margin-bottom: 8px;
}

.paywall__title {
  margin: 0 0 6px;
  font-size: 22px;
  font-weight: 800;
  text-align: center;
}

.paywall__desc {
  margin: 0 0 18px;
  font-size: 13px;
  line-height: 1.55;
  color: var(--color-text-muted);
  text-align: center;
}

.paywall__actions {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.paywall__close {
  position: absolute;
  top: 28px;
  right: 28px;
  width: 32px; height: 32px;
  border-radius: 50%;
  background: var(--color-surface-3);
  color: var(--color-text-muted);
  display: grid;
  place-items: center;
  font-size: 16px;
  transition: background-color var(--t-fast) var(--ease-out),
              color var(--t-fast) var(--ease-out);
}

.paywall__close:hover {
  background: var(--color-surface-2);
  color: var(--color-text);
}

/* ---- Bottom navigation --------------------------------------------------- */

.nav {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border-top: 1px solid var(--color-border);
  background: rgba(6, 7, 10, 0.92);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.nav__btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 4px;
  color: var(--color-text-muted);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  transition: color var(--t-base) var(--ease-out),
              background-color var(--t-base) var(--ease-out);
  position: relative;
}

.nav__btn-icon {
  font-size: 22px;
  line-height: 1;
  transition: transform var(--t-base) var(--ease-out),
              text-shadow var(--t-base) var(--ease-out);
}

.nav__btn:hover {
  color: var(--color-text);
}

.nav__btn.is-active {
  color: var(--color-neon-blue);
}

.nav__btn.is-active .nav__btn-icon {
  transform: translateY(-2px);
  text-shadow: var(--glow-blue);
}

.nav__btn.is-active::after {
  content: '';
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 36px;
  height: 3px;
  border-radius: 0 0 4px 4px;
  background: var(--color-neon-blue);
  box-shadow: var(--glow-blue);
}

/* ---- Responsive tweaks --------------------------------------------------- */

@media (min-width: 720px) {
  .app {
    margin: 24px auto;
    height: calc(100dvh - 48px);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    overflow: hidden;
    box-shadow: 0 30px 80px rgba(0, 0, 0, 0.5);
  }
}

/* Respect user motion preferences. */

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    transition: none !important;
    animation: none !important;
  }
}