:root {
  --ink: #17233b;
  --muted: #697087;
  --paper: #fffdf5;
  --canvas: #f5f0e5;
  --grid-line: rgba(23, 35, 59, 0.035);
  --surface: #ffffff;
  --sun: #ffd84d;
  --sun-soft: #fff4bd;
  --violet: #6c63cf;
  --leaf: #527a35;
  --leaf-soft: #e8f2dc;
  --line: #d9d5c7;
  --white: #ffffff;
  --danger: #c83d36;
  --primary-hover: #5b52be;
  --control-muted: #e4e1d7;
  --progress-track: #e9e5da;
  --wrong-soft: #ffe0dc;
  --outline: var(--ink);
  --shadow-color: var(--ink);
  --selection-fill: var(--ink);
  --radius-sm: 14px;
  --radius-md: 22px;
  --radius-lg: 32px;
  --shadow: 0 10px 0 rgba(23, 35, 59, 0.12);
  font-family: "Noto Sans Thai", system-ui, sans-serif;
  color: var(--ink);
  background: var(--canvas);
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --ink: #e7e5e9;
  --muted: #98959f;
  --paper: #0d0d0f;
  --canvas: #070708;
  --grid-line: rgba(255, 255, 255, 0.018);
  --surface: #151517;
  --sun: #8275d6;
  --sun-soft: #211f2b;
  --violet: #7568d7;
  --leaf: #83a968;
  --leaf-soft: #192119;
  --line: #29282d;
  --danger: #df706b;
  --primary-hover: #665bc4;
  --control-muted: #202023;
  --progress-track: #252428;
  --wrong-soft: #2b1717;
  --outline: #37353b;
  --shadow-color: #000000;
  --selection-fill: #7568d7;
  --shadow: 0 10px 0 rgba(0, 0, 0, 0.62);
}

:root[data-theme="dark"] :is(
  .back-button,
  .category-check,
  .amount-button,
  .primary-button,
  .secondary-button,
  .flashcard__face,
  .celebration-mark,
  .answer-button,
  .speech-dialog,
  .score-ring
) { border-color: var(--outline); }
:root[data-theme="dark"] :is(.category-button, .filter-tab):hover { border-color: var(--outline); }
:root[data-theme="dark"] .filter-tab--selected { border-color: var(--outline); }
:root[data-theme="dark"] .app-shell { border-color: #151517; }
:root[data-theme="dark"] .back-button:active { box-shadow: inset 0 0 0 2px #242328; }

* { box-sizing: border-box; }

body {
  margin: 0;
  min-width: 320px;
  min-height: 100vh;
  background:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    var(--canvas);
  background-size: 100% 32px;
}

:root[data-language="ru"] :is(.meaning, .answer-button) {
  font-family: "Noto Sans", sans-serif;
}

button, input { font: inherit; }
button { cursor: pointer; }

button:focus-visible, input:focus-visible, a:focus-visible {
  outline: 3px solid var(--leaf);
  outline-offset: 3px;
}

.app-shell {
  width: min(100%, 560px);
  min-height: 100vh;
  margin: 0 auto;
  padding: max(20px, env(safe-area-inset-top)) 20px max(28px, env(safe-area-inset-bottom));
  background: var(--paper);
  border-inline: 1px solid rgba(23, 35, 59, 0.08);
}

.brand {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  margin-bottom: 34px;
}
.brand[hidden] { display: none; }
.brand__identity { display: flex; min-width: 0; align-items: center; gap: 14px; }
.brand__controls { display: flex; align-items: center; gap: 10px; }
.brand__link {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-family: "Baloo 2", sans-serif;
  font-weight: 800;
  letter-spacing: 0.02em;
  text-decoration: none;
}
.brand__link strong { color: var(--violet); }
.brand__link > span { white-space: nowrap; }
.brand__logo {
  display: block;
  width: 36px;
  height: 40px;
  object-fit: contain;
}
.theme-button .theme-icon--moon { display: none; }
:root[data-theme="dark"] .theme-button .theme-icon--sun { display: none; }
:root[data-theme="dark"] .theme-button .theme-icon--moon { display: block; }
.language-picker { position: relative; }
.language-button {
  font-family: "Baloo 2", sans-serif;
  font-size: 0.8rem;
  font-weight: 800;
  letter-spacing: 0.02em;
}
.language-menu {
  position: absolute;
  z-index: 20;
  top: calc(100% + 8px);
  right: 0;
  width: 154px;
  padding: 6px;
  border: 2px solid var(--ink);
  border-radius: 18px;
  background: var(--surface);
  box-shadow: var(--shadow);
}
.language-menu[hidden] { display: none; }
.language-menu__title {
  margin: 3px 10px 5px;
  color: var(--muted);
  font-size: 0.7rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}
.language-menu button {
  display: flex;
  width: 100%;
  min-height: 44px;
  align-items: center;
  justify-content: space-between;
  border: 0;
  border-radius: 12px;
  padding: 8px 10px;
  background: transparent;
  color: var(--ink);
  font: 700 0.92rem/1.2 "Noto Sans Thai", sans-serif;
  text-align: left;
}
.language-menu button:hover,
.language-menu button:focus-visible { background: var(--sun-soft); }
.language-menu button[aria-checked="true"] { background: var(--leaf-soft); }
.language-menu button span { color: var(--muted); font: 800 0.76rem/1 "Baloo 2", sans-serif; }
.back-button {
  display: inline-grid;
  width: 44px;
  height: 44px;
  flex: 0 0 44px;
  place-items: center;
  border: 2px solid var(--ink);
  border-radius: 50%;
  padding: 0;
  background: var(--surface);
  color: var(--ink);
  transition: background-color 140ms ease, box-shadow 140ms ease;
}
.back-button:hover { background: var(--sun-soft); }
.back-button:active { box-shadow: inset 0 0 0 2px rgba(23, 35, 59, 0.12); }
.back-button svg {
  width: 24px;
  height: 24px;
  fill: none;
  stroke: currentColor;
  stroke-width: 2.25;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.screen { display: none; }
.screen--active { display: block; animation: screen-in 240ms ease-out; }
.screen--centered { text-align: center; padding-top: 8vh; }

.eyebrow {
  margin: 0 0 8px;
  color: var(--leaf);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

h1, h2 {
  margin: 0;
  font-family: "Baloo 2", sans-serif;
  line-height: 1.02;
}
h1 { max-width: 430px; font-size: clamp(1.55rem, 6vw, 2rem); line-height: 1.15; }
h2 { font-size: clamp(2.15rem, 8vw, 3rem); }
.intro { margin-bottom: 22px; }

.category-list { display: grid; gap: 12px; margin-bottom: 18px; }
.category-button {
  display: flex;
  width: 100%;
  min-height: 68px;
  align-items: center;
  gap: 14px;
  border: 2px solid var(--line);
  border-radius: var(--radius-md);
  padding: 12px 16px;
  background: var(--surface);
  color: var(--ink);
  text-align: left;
  transition: min-height 180ms ease, padding 180ms ease, border-color 160ms ease, background-color 160ms ease, box-shadow 160ms ease;
}
.category-button:hover { border-color: var(--ink); }
.category-button:disabled { cursor: not-allowed; opacity: 0.42; }
.category-button--selected { min-height: 100px; border-color: var(--outline); padding-block: 16px; background: var(--sun-soft); box-shadow: 4px 4px 0 var(--shadow-color); }
.category-check {
  display: grid;
  width: 26px;
  height: 26px;
  flex: 0 0 26px;
  place-items: center;
  border: 2px solid var(--ink);
  border-radius: 7px;
  background: var(--surface);
}
.category-check span {
  width: 7px;
  height: 12px;
  border-right: 2px solid currentColor;
  border-bottom: 2px solid currentColor;
  opacity: 0;
  transform: translateY(-1px) rotate(45deg);
}
.category-button--selected .category-check { background: var(--selection-fill); color: var(--white); }
.category-button--selected .category-check span { opacity: 1; }
.category-button__content { min-width: 0; flex: 1; }
.category-button__head { display: flex; align-items: baseline; justify-content: space-between; gap: 12px; }
.category-button__head strong { font-family: "Baloo 2", sans-serif; font-size: 1.25rem; }
.category-button__head span { color: var(--muted); font-size: 0.78rem; font-weight: 700; white-space: nowrap; }
.category-button__description { display: none; margin-top: 2px; }
.category-button--selected .category-button__description { display: block; }

.filter-tabs {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
  margin-top: 20px;
}
.filter-tab {
  display: inline-flex;
  min-height: 48px;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border: 2px solid var(--line);
  border-radius: 14px;
  padding: 8px 10px;
  background: var(--surface);
  color: var(--muted);
  font-weight: 800;
  transition: border-color 160ms ease, background-color 160ms ease, color 160ms ease, box-shadow 160ms ease;
}
.filter-tab__count {
  min-width: 26px;
  border-radius: 999px;
  padding: 2px 7px;
  background: var(--control-muted);
  color: var(--ink);
  font-size: 0.72rem;
  font-variant-numeric: tabular-nums;
  line-height: 1.35;
}
.filter-tab > span:first-child { white-space: nowrap; }
.filter-tab--selected .filter-tab__count { background: var(--surface); }
.filter-tab:hover { border-color: var(--ink); color: var(--ink); }
.filter-tab--selected {
  border-color: var(--ink);
  background: var(--leaf-soft);
  color: var(--ink);
  box-shadow: 3px 3px 0 var(--shadow-color);
}
.filter-tab:disabled {
  cursor: not-allowed;
  border-color: var(--line);
  background: var(--control-muted);
  color: var(--muted);
  opacity: 0.5;
  box-shadow: none;
}

.amount-picker { display: grid; grid-template-columns: repeat(4, 1fr); gap: 10px; margin-top: 24px; }
.amount-button {
  min-height: 64px;
  border: 2px solid var(--ink);
  border-radius: var(--radius-sm);
  background: var(--surface);
  color: var(--ink);
  font-family: "Baloo 2", sans-serif;
  font-size: 1.4rem;
  font-weight: 800;
  transition: background-color 160ms ease, box-shadow 160ms ease;
}
.amount-button:hover { background: var(--sun-soft); }
.amount-button--selected { background: var(--sun); box-shadow: 4px 4px 0 var(--shadow-color); }
.amount-button:disabled {
  cursor: not-allowed;
  border-color: var(--line);
  background: var(--control-muted);
  color: var(--muted);
  opacity: 0.45;
  box-shadow: none;
}

.primary-button, .secondary-button {
  width: 100%;
  min-height: 56px;
  border: 2px solid var(--ink);
  border-radius: var(--radius-sm);
  padding: 12px 20px;
  font-weight: 800;
  transition: background-color 160ms ease, opacity 160ms ease, box-shadow 160ms ease;
}
.primary-button { background: var(--violet); color: var(--white); box-shadow: 4px 4px 0 var(--shadow-color); }
#setup-screen > .primary-button { margin-top: 24px; }
.primary-button:hover { background: var(--primary-hover); }
.secondary-button { background: var(--surface); color: var(--ink); }
.secondary-button:hover { background: var(--sun-soft); }
.primary-button:disabled { cursor: not-allowed; opacity: 0.35; box-shadow: none; }
.text-button {
  min-height: 48px;
  border: 0;
  padding: 8px;
  background: transparent;
  color: var(--leaf);
  font-weight: 800;
  text-decoration: underline;
  text-underline-offset: 4px;
}

.study-head { display: flex; align-items: center; justify-content: space-between; min-height: 48px; }
.study-head p { margin: 0; color: var(--muted); }
.study-head--compact {
  display: grid;
  grid-template-columns: 44px minmax(70px, 1fr) auto 44px 44px 44px;
  gap: 14px;
  margin-bottom: 24px;
}
.audio-button--speaking { background: var(--leaf-soft); color: var(--leaf); }
.back-button:disabled { cursor: not-allowed; opacity: 0.4; }
.quiz-head {
  display: grid;
  grid-template-columns: 44px minmax(80px, 1fr) auto;
  gap: 14px;
}
.quiz-head .eyebrow { margin: 0; text-align: center; }
.progress.study-head__progress { width: 100%; margin: 0; }
.progress { height: 8px; margin: 8px 0 28px; overflow: hidden; border-radius: 99px; background: var(--progress-track); }
.progress span { display: block; height: 100%; border-radius: inherit; background: var(--leaf); transition: width 200ms ease; }
.card-stage { perspective: 1200px; touch-action: pan-y; }
.card-stage--blocked { animation: card-blocked 320ms ease-out; }
.card-stage--blocked .flashcard__face { border-color: var(--danger); }
.card-stage--exit-left { animation: card-exit-left 170ms ease-in forwards; }
.card-stage--exit-right { animation: card-exit-right 170ms ease-in forwards; }
.card-stage--enter-right { animation: card-enter-right 220ms cubic-bezier(.2,.75,.25,1); }
.card-stage--enter-left { animation: card-enter-left 220ms cubic-bezier(.2,.75,.25,1); }
.flashcard {
  display: block;
  width: 100%;
  height: min(58vh, 460px);
  min-height: 360px;
  border: 0;
  padding: 0;
  background: transparent;
}
.flashcard__inner {
  position: relative;
  display: block;
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
  transition: transform 440ms cubic-bezier(.2,.75,.25,1);
}
.flashcard--flipped .flashcard__inner { transform: rotateY(180deg); }
.flashcard__face {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  border: 3px solid var(--ink);
  border-radius: var(--radius-lg);
  padding: 32px;
  backface-visibility: hidden;
  box-shadow: var(--shadow);
  transition: border-color 140ms ease;
}
.flashcard__front { background: var(--sun-soft); }
.flashcard__back { background: var(--leaf-soft); transform: rotateY(180deg); }
.card-label { position: absolute; top: 28px; color: var(--muted); font-size: 0.75rem; font-weight: 800; letter-spacing: 0.12em; text-transform: uppercase; }
.word, .meaning { font-family: "Baloo 2", "Noto Sans Thai", sans-serif; line-height: 1.1; text-align: center; }
.word { font-size: clamp(3rem, 13vw, 5.3rem); }
.meaning { max-width: 430px; font-size: clamp(2rem, 8vw, 3.5rem); }
.flashcard--irregular .meaning { font-size: clamp(1.85rem, 7.5vw, 3.2rem); }
.part, .pronunciation { margin-top: 12px; color: var(--muted); }
.flip-hint { position: absolute; bottom: 26px; color: var(--muted); font-size: 0.82rem; }
.swipe-hint { margin: 20px 0 14px; color: var(--muted); text-align: center; font-size: 0.78rem; }
.swipe-hint--error { color: var(--danger); font-weight: 800; }
.study-actions { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }

.celebration-mark {
  display: grid;
  width: 96px;
  height: 96px;
  margin: 0 auto 28px;
  place-items: center;
  border: 3px solid var(--ink);
  border-radius: 50%;
  background: var(--sun);
  box-shadow: 6px 6px 0 var(--shadow-color);
  font: 800 3rem/1 "Baloo 2", sans-serif;
}
.screen--centered > p:not(.eyebrow) { margin: 18px auto 32px; color: var(--muted); }
.screen--centered .primary-button, .screen--centered .secondary-button { margin-top: 12px; }
#ready-screen .celebration-mark { margin-bottom: 34px; }
#ready-screen .eyebrow { margin-bottom: 14px; }
#ready-screen .primary-button { margin-top: 36px; }
#ready-screen #review-button { display: block; margin: 22px auto 0; }

.question { padding: 34px 16px 26px; text-align: center; }
.question p { margin: 0 0 4px; color: var(--muted); }
.question h2 { font-size: clamp(3rem, 12vw, 5rem); }
.question span { color: var(--muted); }
.answers { display: grid; gap: 12px; }
.answer-button {
  min-height: 68px;
  border: 2px solid var(--ink);
  border-radius: var(--radius-sm);
  padding: 14px 18px;
  background: var(--surface);
  color: var(--ink);
  font-weight: 700;
  text-align: left;
  transition: background-color 140ms ease;
}
.answer-button:hover:not(:disabled) { background: var(--sun-soft); }
.answer-button--correct { background: var(--leaf-soft); border-color: var(--leaf); }
.answer-button--wrong { background: var(--wrong-soft); border-color: var(--danger); }
.quiz-screen--forms .answer-button { font-size: 1.15rem; text-align: center; }

.speech-dialog {
  width: min(calc(100% - 32px), 480px);
  border: 3px solid var(--ink);
  border-radius: var(--radius-md);
  padding: 0;
  background: var(--paper);
  color: var(--ink);
  box-shadow: 8px 8px 0 var(--shadow-color);
}
.speech-dialog::backdrop { background: rgba(15, 14, 25, 0.62); }
.speech-dialog form { padding: 24px; }
.speech-dialog__head { display: flex; align-items: flex-start; justify-content: space-between; gap: 20px; margin-bottom: 26px; }
.speech-dialog__head h2 { font-size: 2rem; }
.voice-picker, .speed-picker { border: 0; padding: 0; }
.voice-picker legend, .speed-picker legend { display: block; margin-bottom: 8px; font-weight: 800; }
.voice-list { display: grid; max-height: 240px; gap: 8px; overflow-y: auto; padding: 2px 7px 7px 2px; }
.voice-option {
  display: grid;
  grid-template-columns: 24px minmax(0, 1fr);
  gap: 12px;
  align-items: center;
  min-height: 54px;
  border: 2px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 9px 12px;
  background: var(--surface);
  cursor: pointer;
}
.voice-option:has(input:checked) { border-color: var(--outline); background: var(--sun-soft); box-shadow: 3px 3px 0 var(--shadow-color); }
.voice-option input { width: 20px; height: 20px; margin: 0; accent-color: var(--purple); }
.voice-option span { min-width: 0; overflow: hidden; font-weight: 700; text-overflow: ellipsis; white-space: nowrap; }
.voice-option small { display: block; color: var(--muted); font-weight: 500; }
.speed-picker { margin: 24px 0; border: 0; padding: 0; }
.speed-picker > div { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; }
.speed-picker button {
  min-height: 48px;
  border: 2px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--surface);
  color: var(--ink);
  font-weight: 800;
}
.speed-picker button[aria-pressed="true"] { border-color: var(--outline); background: var(--sun-soft); box-shadow: 3px 3px 0 var(--shadow-color); }

.score-ring {
  display: flex;
  width: 150px;
  height: 150px;
  margin: 10px auto 30px;
  align-items: baseline;
  justify-content: center;
  padding-top: 35px;
  border: 4px solid var(--ink);
  border-radius: 50%;
  background: var(--sun);
  box-shadow: 7px 7px 0 var(--shadow-color);
  font-family: "Baloo 2", sans-serif;
}
.score-ring strong { font-size: 4rem; line-height: 1; }
.score-ring span { font-size: 1.2rem; font-weight: 700; }

@keyframes screen-in { from { opacity: 0; transform: translateY(8px); } }
@keyframes card-blocked {
  0%, 100% { transform: translateX(0); }
  30% { transform: translateX(-9px); }
  60% { transform: translateX(7px); }
  80% { transform: translateX(-3px); }
}
@keyframes card-exit-left {
  to { opacity: 0; transform: translateX(-22%) rotate(-1.5deg); }
}
@keyframes card-exit-right {
  to { opacity: 0; transform: translateX(22%) rotate(1.5deg); }
}
@keyframes card-enter-right {
  from { opacity: 0; transform: translateX(18%) rotate(1deg); }
  to { opacity: 1; transform: translateX(0) rotate(0); }
}
@keyframes card-enter-left {
  from { opacity: 0; transform: translateX(-18%) rotate(-1deg); }
  to { opacity: 1; transform: translateX(0) rotate(0); }
}

@media (min-width: 700px) {
  .app-shell { min-height: calc(100vh - 40px); margin-block: 20px; padding-inline: 42px; border-radius: 28px; }
}

@media (max-width: 520px) {
  .filter-tab { min-height: 76px; flex-direction: column; gap: 3px; padding-inline: 5px; }
}

@media (max-width: 390px) {
  .app-shell { padding-inline: 14px; }
  .brand { gap: 10px; }
  .brand__identity { gap: 10px; }
  .brand__controls { gap: 7px; }
  .brand__link { gap: 7px; font-size: 0.72rem; }
  .brand__logo { width: 30px; height: 34px; }
  .study-head--compact { grid-template-columns: 44px minmax(40px, 1fr) auto 44px 44px 44px; gap: 7px; }
  .filter-tab { min-height: 72px; }
  .amount-picker { gap: 7px; }
  .amount-button { min-height: 58px; }
  .flashcard { min-height: 330px; height: 52vh; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: 0.01ms !important; animation-duration: 0.01ms !important; }
}