:root {
  color-scheme: light;
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", ui-sans-serif, sans-serif;
  --font-mono: "SF Mono", Menlo, Consolas, monospace;
  --background: #ffffff;
  --background-subtle: #00000005;
  --bg-1: #ffffff;
  --bg-2: #0000000a;
  --bg-3: #0000000f;
  --bg-4: #00000017;
  --fg-1: #0000004d;
  --fg-2: #00000066;
  --fg-3: #00000099;
  --fg-4: #000000e6;
  --bg-a1: #00000008;
  --bg-a2: #0000000d;
  --bg-a3: #00000014;
  --fg-a2: #00000066;
  --purple-1: #fff1f1;
  --purple-2: #ffdada;
  --purple-4: #f04747;
  --sky-1: #ebf2ff;
  --sky-2: #bed5fe;
  --sky-4: #2c78fc;
  --green-1: #effbf2;
  --green-4: #33c758;
  --red-1: #fff3f0;
  --red-4: #ff2f00;
  --shadow-1: none;
  --shadow-2: 0 1px 3px #00000014, 0 0 0 1px #00000005;
  --shadow-3: 0 1px 3px #0000000f, 0 8px 16px #0000000f, 0 0 0 1px #00000005;
  --text-large-title: 34px;
  --leading-large-title: 121%;
  --text-title-1: 28px;
  --leading-title-1: 121%;
  --text-title-3: 17px;
  --leading-title-3: 129%;
  --text-headline: 17px;
  --leading-headline: 129%;
  --text-body: 17px;
  --leading-body: 129%;
  --text-callout: 16px;
  --leading-callout: 131%;
  --text-subhead: 15px;
  --leading-subhead: 133%;
  --text-footnote: 13px;
  --leading-footnote: 138%;
  --text-metric: 64px;
  --leading-metric: 109%;
  --danger-bg: #ffffff;
  --danger-fg: #b91c1c;
  --danger-border: #fecaca;
  --danger-bg-hover: #feefef;
  --overlay-scrim: #0000001f;
  --grade-new: var(--purple-4);
  --grade-f: #ef4444;
  --grade-e: #f97316;
  --grade-d: #fb923c;
  --grade-c: #fbbf24;
  --grade-b: #38bdf8;
  --grade-a: #22c55e;
  --rating-again-bg: #f973161a;
  --rating-again-fg: #ea580c;
  --rating-hard-bg: #fbbf2429;
  --rating-hard-fg: #d97706;
  --rating-good-bg: #0ea5e921;
  --rating-good-fg: #0284c7;
  --rating-easy-bg: #84cc1626;
  --rating-easy-fg: #65a30d;
  --activity-1: #ffe0e0;
  --activity-2: #ffb8b8;
  --activity-3: #f04747;
  --activity-4: #d63a3a;
  --text-display-zh: 48px;
  --text-counter: 24px;
  --text-rating: 22px;
  --text-nav: 12px;
  --text-learn-cell: 14px;
  --text-learn-letter: 26px;
  --radius-4: 8px;
  --radius-3: 6px;
  --radius-5: 12px;
  --radius-6: 16px;
  --radius-3xl: 24px;
  --radius-pill: 9999px;
  --ease-out: cubic-bezier(0.23, 1, 0.32, 1);
  --ease-in-out: cubic-bezier(0.77, 0, 0.175, 1);
  --motion-fast: 140ms;
  --motion-base: 180ms;
  --motion-slow: 240ms;
}

* {
  box-sizing: border-box;
}

[hidden] {
  display: none !important;
}

html {
  min-height: 100%;
  font-family: var(--font-sans);
  background: var(--background);
  color: var(--fg-4);
  letter-spacing: 0;
  -webkit-text-size-adjust: 100%;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

body {
  min-height: 100vh;
  margin: 0;
  background: var(--background);
  padding-bottom: 124px;
  -webkit-tap-highlight-color: transparent;
}

body.review-active {
  overflow: hidden;
  padding-bottom: 0;
}

body.home-active:not(.review-active) {
  overflow: hidden;
  padding-bottom: 0;
}

button,
input,
select {
  font: inherit;
}

button {
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
  user-select: none;
  -webkit-user-select: none;
}

.app-shell {
  width: min(100%, 1064px);
  margin: 0 auto;
  padding: 20px max(20px, env(safe-area-inset-right)) 0 max(20px, env(safe-area-inset-left));
}

.nav-tab,
.button,
.icon-button {
  border: 0;
  border-radius: var(--radius-pill);
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
  user-select: none;
  -webkit-user-select: none;
  transition: transform var(--motion-fast) var(--ease-out), background-color var(--motion-base) ease, color var(--motion-base) ease, opacity var(--motion-base) ease;
}

.nav-tab {
  position: relative;
  z-index: 1;
  display: grid;
  min-width: 84px;
  min-height: 52px;
  place-items: center;
  gap: 3px;
  padding: 6px 12px;
  background: transparent;
  color: var(--fg-3);
  font-size: 12px;
  font-weight: 500;
  touch-action: manipulation;
  transition: color var(--motion-base) ease;
}

.nav-tab.is-active {
  color: var(--purple-4);
}

main {
  padding: 18px 0 28px;
}

#view-home {
  width: min(100%, 420px);
  height: calc(100dvh - 46px);
  max-height: calc(100dvh - 46px);
  margin: 0 auto;
  overflow: hidden;
}

.view {
  display: none;
}

.view.is-active {
  display: block;
  animation: view-enter var(--motion-slow) var(--ease-out) both;
}

body.review-active .view.is-active {
  animation: none;
  transform: none;
}

.word-day-card,
.review-card {
  border: 1px solid var(--bg-a2);
  border-radius: var(--radius-3xl);
  background: color-mix(in srgb, var(--background) 92%, transparent);
  box-shadow: var(--shadow-1);
}

.home-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 18px;
}

.streak-pill {
  display: inline-flex;
  min-height: 32px;
  align-items: center;
  gap: 6px;
  padding: 0 12px;
  border: 0;
  border-radius: var(--radius-pill);
  background: var(--bg-a1);
  color: var(--fg-3);
  font-size: var(--text-subhead);
  font-weight: 500;
  line-height: var(--leading-subhead);
  white-space: nowrap;
}

.streak-pill svg {
  width: 17px;
  height: 17px;
  fill: none;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.streak-pill strong {
  font-weight: inherit;
}

h1,
h2 {
  margin: 0;
  color: var(--fg-4);
  font-weight: 600;
  text-wrap: balance;
}

h1 {
  font-size: var(--text-large-title);
  line-height: var(--leading-large-title);
  font-weight: 700;
  letter-spacing: 0;
}

h2 {
  font-size: var(--text-title-1);
  line-height: var(--leading-title-1);
}

#home-title {
  font-size: var(--text-title-1);
  line-height: var(--leading-title-1);
  font-weight: 600;
}

.review-actions,
.rating-actions,
.split-actions,
.filters {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.button {
  min-height: 40px;
  padding: 0 18px;
  font-size: var(--text-headline);
  font-weight: 600;
  line-height: var(--leading-headline);
}

.button:active,
.icon-button:active {
  transform: scale(0.97);
}

.button-primary {
  background: var(--purple-4);
  color: #ffffff;
}

.button-secondary {
  background: var(--bg-a1);
  color: var(--fg-4);
}

.word-day-card {
  position: relative;
  display: grid;
  width: 100%;
  min-height: 206px;
  align-content: center;
  gap: 6px;
  margin: 0 0 12px;
  padding: 20px;
  border: 1px solid var(--bg-a2);
  border-radius: var(--radius-6);
  background: var(--background);
  color: inherit;
  text-align: center;
  box-shadow: none;
}

.word-day-card strong {
  color: var(--fg-4);
  font-size: var(--text-large-title);
  font-weight: 600;
  line-height: var(--leading-large-title);
}

#word-day-romanization {
  color: var(--fg-3);
  font-size: var(--text-body);
  font-weight: 500;
  line-height: var(--leading-body);
}

.word-day-example {
  display: grid;
  gap: 4px;
  margin-top: 8px;
  padding-top: 0;
  color: var(--fg-2);
  font-size: var(--text-subhead);
  font-weight: 500;
  line-height: var(--leading-subhead);
}

.start-review-button {
  width: 100%;
  min-height: 52px;
  margin: 16px 0 30px;
  border-radius: var(--radius-pill);
  font-size: var(--text-headline);
  line-height: var(--leading-headline);
}

.grade-panel {
  position: relative;
  min-height: 334px;
}

.session-summary {
  margin: 14px 0 0;
  padding: 0;
}

.session-summary-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.session-summary-stats span {
  display: grid;
  min-height: 96px;
  align-content: start;
  gap: 8px;
  padding: 16px;
  border-radius: var(--radius-5);
  background: var(--bg-a1);
  text-align: left;
}

.session-summary-stats span + span {
  border-left: 0;
}

.session-summary-stats strong {
  color: var(--fg-4);
  font-size: var(--text-title-1);
  font-weight: 600;
  line-height: var(--leading-title-1);
  font-variant-numeric: tabular-nums;
}

.session-summary-stats em {
  color: var(--fg-3);
  font-size: var(--text-footnote);
  font-style: normal;
  font-weight: 600;
  letter-spacing: 0;
  line-height: var(--leading-footnote);
  text-transform: none;
}

.activity-popover {
  position: fixed;
  inset: 0;
  z-index: 80;
  display: grid;
  align-items: end;
  justify-items: stretch;
  padding: 0;
  background: var(--overlay-scrim);
  overflow: hidden;
  -webkit-overflow-scrolling: touch;
}

.activity-popover[hidden] {
  display: none !important;
}

.activity-popover .activity-panel {
  width: 100%;
  margin: 0;
  padding: 10px max(20px, env(safe-area-inset-right)) max(20px, env(safe-area-inset-bottom)) max(20px, env(safe-area-inset-left));
  border-right: 0;
  border-bottom: 0;
  border-left: 0;
  border-radius: 28px 28px 0 0;
  background: var(--background);
  animation: sheet-enter 220ms var(--ease-out) both;
}

.activity-popover .activity-panel::before {
  content: "";
  display: block;
  width: 36px;
  height: 4px;
  margin: 0 auto 12px;
  border-radius: var(--radius-pill);
  background: var(--bg-a3);
}

.activity-popover .panel-header {
  padding: 0;
  margin-bottom: 14px;
}

.modal-backdrop {
  position: fixed;
  inset: 0;
  z-index: 90;
  display: grid;
  place-items: center;
  padding: max(18px, env(safe-area-inset-top)) max(18px, env(safe-area-inset-right)) max(18px, env(safe-area-inset-bottom)) max(18px, env(safe-area-inset-left));
  background: var(--overlay-scrim);
}

.modal-backdrop[hidden] {
  display: none !important;
}

.confirm-modal {
  width: min(100%, 360px);
  padding: 20px;
  border: 1px solid var(--bg-a2);
  border-radius: var(--radius-3xl);
  background: var(--background);
  box-shadow: none;
  animation: modal-enter var(--motion-base) var(--ease-out) both;
}

.confirm-modal h2 {
  margin: 0;
  color: var(--fg-4);
  font-size: var(--text-title-3);
  font-weight: 600;
  line-height: var(--leading-title-3);
}

.confirm-modal p {
  margin: 8px 0 0;
  color: var(--fg-2);
  font-size: var(--text-body);
  font-weight: 500;
  line-height: var(--leading-body);
}

.modal-actions {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px;
  margin-top: 18px;
}

.modal-actions .button {
  width: 100%;
}

.danger-button {
  background: var(--danger-bg);
  border: 1px solid var(--danger-border);
  color: var(--danger-fg);
}

.home-panel {
  margin-top: 12px;
  padding: 16px;
  border: 1px solid var(--bg-a2);
  border-radius: var(--radius-6);
  background: var(--background);
  box-shadow: none;
}

.panel-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 14px;
}

.panel-header h2 {
  font-size: var(--text-headline);
  line-height: var(--leading-headline);
}

.last-session-pill {
  display: inline-flex;
  min-height: 32px;
  align-items: center;
  justify-content: center;
  padding: 5px 12px;
  border-radius: var(--radius-pill);
  background: var(--purple-1);
  color: var(--purple-4);
  font-size: var(--text-subhead);
  font-weight: 500;
  line-height: var(--leading-subhead);
  font-variant-numeric: tabular-nums;
}

.grade-chart {
  display: grid;
  grid-template-columns: repeat(7, minmax(0, 1fr));
  align-items: end;
  gap: 8px;
  min-height: 148px;
}

.grade-item {
  display: grid;
  grid-template-rows: 24px 100px 22px;
  align-items: end;
  justify-items: center;
  gap: 4px;
  min-width: 0;
}

.grade-count {
  color: var(--fg-3);
  font-size: var(--text-footnote);
  font-weight: 600;
  line-height: var(--leading-footnote);
  font-variant-numeric: tabular-nums;
}

.grade-bar {
  display: block;
  width: 100%;
  max-width: 38px;
  min-height: 4px;
  border-radius: var(--radius-3) var(--radius-3) 2px 2px;
  background: var(--purple-4);
}

.grade-label {
  color: var(--fg-3);
  font-size: var(--text-subhead);
  font-weight: 500;
  line-height: var(--leading-subhead);
}

.grade-new .grade-bar {
  background: var(--grade-new);
}

.grade-f .grade-bar {
  background: var(--grade-f);
}

.grade-e .grade-bar {
  background: var(--grade-e);
}

.grade-d .grade-bar {
  background: var(--grade-d);
}

.grade-c .grade-bar {
  background: var(--grade-c);
}

.grade-b .grade-bar {
  background: var(--grade-b);
}

.grade-a .grade-bar {
  background: var(--grade-a);
}

.app-loading .word-day-card,
.app-loading .grade-panel {
  pointer-events: none;
}

.word-day-skeleton,
.grade-skeleton {
  display: none;
}

.app-loading .word-day-card > :not(.word-day-skeleton),
.app-loading .grade-panel .panel-header,
.app-loading .grade-chart,
.app-loading .session-summary {
  visibility: hidden;
}

.app-loading .word-day-skeleton,
.app-loading .grade-skeleton {
  display: grid;
}

.app-loading .word-day-skeleton {
  position: absolute;
  inset: 20px;
  align-content: center;
}

.app-loading .grade-skeleton {
  position: absolute;
  inset: 16px;
}

.skeleton-line,
.grade-skeleton-chart span,
.grade-skeleton-stats span {
  display: block;
  overflow: hidden;
  border-radius: var(--radius-pill);
  background:
    linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.62), transparent),
    linear-gradient(var(--bg-a1), var(--bg-a1));
  background-size: 180px 100%, 100% 100%;
  background-position: -180px 0, 0 0;
  animation: skeleton-shimmer 1.4s var(--ease-out) infinite;
}

.skeleton-stack {
  justify-items: center;
  gap: 8px;
  width: 100%;
}

.skeleton-line-small {
  width: 104px;
  height: 16px;
}

.skeleton-line-large {
  width: min(78%, 280px);
  height: 42px;
  border-radius: var(--radius-4);
}

.skeleton-line-medium {
  width: 150px;
  height: 20px;
}

.skeleton-line-example {
  width: 180px;
  height: 18px;
  margin-top: 8px;
}

.grade-skeleton {
  gap: 14px;
}

.grade-skeleton-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.skeleton-title {
  width: 64px;
  height: 22px;
}

.skeleton-pill {
  width: 128px;
  height: 32px;
}

.grade-skeleton-chart {
  display: grid;
  grid-template-columns: repeat(7, minmax(0, 1fr));
  align-items: end;
  gap: 8px;
  min-height: 154px;
}

.grade-skeleton-chart span {
  width: 100%;
  max-width: 38px;
  min-height: 4px;
  justify-self: center;
  border-radius: var(--radius-3) var(--radius-3) 2px 2px;
}

.grade-skeleton-chart span:nth-child(1) {
  height: 92px;
}

.grade-skeleton-chart span:nth-child(2) {
  height: 10px;
}

.grade-skeleton-chart span:nth-child(3),
.grade-skeleton-chart span:nth-child(4),
.grade-skeleton-chart span:nth-child(5),
.grade-skeleton-chart span:nth-child(6),
.grade-skeleton-chart span:nth-child(7) {
  height: 6px;
}

.grade-skeleton-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.grade-skeleton-stats span {
  height: 72px;
  border-radius: var(--radius-5);
}

@keyframes skeleton-shimmer {
  to {
    background-position: calc(100% + 180px) 0, 0 0;
  }
}

.activity-scroll {
  display: grid;
  justify-content: center;
  overflow-x: auto;
  padding: 0 0 4px;
  scrollbar-width: none;
  -webkit-overflow-scrolling: touch;
}

.activity-scroll::-webkit-scrollbar {
  display: none;
}

.activity-grid {
  --activity-cell-size: 16px;
  --activity-gap: 4px;
  --activity-grid-columns: 15;
  --activity-grid-width: 296px;
  display: grid;
  grid-template-columns: repeat(var(--activity-grid-columns), var(--activity-cell-size));
  gap: var(--activity-gap);
  width: var(--activity-grid-width);
  min-width: var(--activity-grid-width);
}

.activity-cell {
  display: block;
  width: var(--activity-cell-size);
  height: var(--activity-cell-size);
  min-width: 0;
  border-radius: 2px;
  background: var(--bg-a2);
}

.activity-cell.is-future {
  opacity: 0.36;
}

.activity-cell.level-1 {
  background: var(--activity-1);
}

.activity-cell.level-2 {
  background: var(--activity-2);
}

.activity-cell.level-3 {
  background: var(--activity-3);
}

.activity-cell.level-4 {
  background: var(--activity-4);
}

@media (min-width: 375px) {
  .activity-grid {
    --activity-cell-size: 20px;
    --activity-grid-width: 356px;
  }
}

@media (min-width: 430px) {
  .activity-grid {
    --activity-cell-size: 22px;
    --activity-grid-width: 386px;
  }
}

.stat-label {
  color: var(--fg-3);
  font-size: var(--text-footnote);
  font-weight: 600;
  line-height: var(--leading-footnote);
}

.stat-value {
  color: var(--fg-4);
  font-size: var(--text-large-title);
  font-weight: 600;
  line-height: var(--leading-large-title);
  font-variant-numeric: tabular-nums;
}

.review-card {
  margin-top: 24px;
  padding: 24px;
}

body.review-active #review-overlay {
  position: fixed;
  inset: 0;
  z-index: 50;
  display: grid;
  grid-template-rows: auto auto minmax(0, 1fr);
  margin: 0;
  padding: max(18px, env(safe-area-inset-top)) max(20px, env(safe-area-inset-right)) 112px max(20px, env(safe-area-inset-left));
  border-radius: 0;
  background: var(--background);
  box-shadow: none;
  overflow-y: auto;
  animation: review-enter var(--motion-slow) var(--ease-out) both;
}

body.review-active .bottom-nav,
body.review-active #view-home {
  display: none;
}

#review-overlay[hidden] {
  display: none !important;
}

.bottom-nav {
  --active-index: 0;
  --active-offset: 0px;
  position: fixed;
  right: 50%;
  bottom: 24px;
  z-index: 20;
  display: inline-flex;
  gap: 4px;
  padding: 6px;
  border-radius: 34px;
  background: color-mix(in srgb, var(--background) 92%, transparent);
  box-shadow: var(--shadow-3);
  transform: translateX(50%);
  backdrop-filter: blur(16px);
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
  user-select: none;
  -webkit-user-select: none;
  transition: transform var(--motion-slow) var(--ease-out), box-shadow var(--motion-base) ease;
}

.bottom-nav::before {
  content: "";
  position: absolute;
  top: 6px;
  left: 6px;
  width: 84px;
  height: 52px;
  border-radius: var(--radius-pill);
  background: var(--purple-1);
  transform: translateX(var(--active-offset));
  transition: transform var(--motion-slow) var(--ease-out);
  pointer-events: none;
}

.bottom-nav svg {
  width: 20px;
  height: 20px;
  fill: none;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.nav-character {
  display: inline-flex;
  width: 20px;
  height: 20px;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  font-weight: 600;
  line-height: 100%;
}

.home-actions {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.script-toggle {
  display: inline-flex;
  min-height: 36px;
  align-items: center;
  gap: 2px;
  padding: 3px;
  border-radius: var(--radius-pill);
  background: var(--bg-a1);
}

.script-toggle button {
  display: inline-flex;
  min-width: 32px;
  min-height: 30px;
  align-items: center;
  justify-content: center;
  border: 0;
  border-radius: var(--radius-pill);
  background: transparent;
  color: var(--fg-3);
  font-size: 14px;
  font-weight: 600;
  transition: background-color var(--motion-base) ease, color var(--motion-base) ease;
}

.script-toggle button.is-active {
  background: var(--background);
  color: var(--purple-4);
  box-shadow: var(--shadow-2);
}

.learn-stack {
  display: grid;
  gap: 12px;
}

.concept-list {
  display: grid;
}

.concept-list div {
  display: grid;
  gap: 6px;
  padding: 14px 18px;
  border-bottom: 1px solid var(--bg-a2);
}

.concept-list div:last-child {
  border-bottom: 0;
}

.concept-list strong {
  color: var(--fg-4);
  font-size: 17px;
  font-weight: 600;
  line-height: var(--leading-headline);
}

.concept-list span {
  color: var(--fg-3);
  font-size: 14px;
  font-weight: 500;
  line-height: 140%;
}

.concept-list code {
  width: fit-content;
  padding: 4px 7px;
  border-radius: var(--radius-3);
  background: var(--bg-a1);
  color: var(--fg-3);
  font-family: var(--font-mono);
  font-size: 12px;
}

.panel-description {
  margin: -4px 18px 0;
  color: var(--fg-3);
  font-size: 14px;
  font-weight: 500;
  line-height: 145%;
}

.mini-reference-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  padding: 0 18px 18px;
}

.mini-reference-grid div {
  display: grid;
  gap: 6px;
  padding: 14px;
  border-radius: var(--radius-5);
  background: var(--bg-a1);
}

.mini-reference-grid strong {
  color: var(--fg-4);
  font-size: 18px;
  font-weight: 600;
}

.mini-reference-grid span {
  color: var(--fg-3);
  font-size: 14px;
  font-weight: 500;
}

.compact-table .learn-row {
  grid-template-columns: 56px minmax(72px, 0.7fr) minmax(0, 1fr);
}

.particle-table .learn-row {
  grid-template-columns: 72px 88px minmax(0, 1fr) minmax(160px, 1.1fr);
}

.review-meta,
.section-heading {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

body.review-active .review-meta {
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr) 44px;
  min-height: 44px;
  position: relative;
}

.review-counters {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  justify-self: center;
}

.counter-pill {
  display: inline-flex;
  min-width: 76px;
  min-height: 42px;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-pill);
  background: var(--bg-a1);
  color: var(--fg-3);
  font-size: 24px;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  transition: background-color var(--motion-base) ease, color var(--motion-base) ease, transform var(--motion-fast) var(--ease-out);
}

.counter-rest {
  color: #b91c1c;
}

.counter-easy {
  color: #15803d;
}

.counter-arrow {
  color: var(--fg-1);
  font-size: 22px;
  font-weight: 600;
}

.badge {
  display: inline-flex;
  min-height: 28px;
  align-items: center;
  justify-content: center;
  padding: 0 10px;
  border-radius: var(--radius-3);
  background: var(--bg-a1);
  color: var(--fg-a2);
  font-size: 14px;
  font-weight: 600;
}

.muted {
  color: var(--fg-2);
  font-size: 14px;
  font-variant-numeric: tabular-nums;
}

.card-face {
  display: grid;
  gap: 18px;
  justify-items: center;
  padding: 52px 16px 36px;
}

body.review-active .card-face {
  display: grid;
  grid-template-rows: auto;
  align-content: start;
  align-self: start;
  padding: 56px 0;
  position: relative;
}

.prompt-panel {
  display: grid;
  width: min(100%, 780px);
  min-height: 240px;
  place-items: center;
  box-shadow: none;
  border-radius: var(--radius-3xl);
  background: var(--background);
  padding: 24px;
}

body.review-active .answer-panel {
  width: min(100%, 628px);
  height: 100%;
  min-height: 0;
  align-content: center;
  margin: 0 auto;
  box-shadow: inset 0 0 0 1px var(--bg-a3);
  border-radius: var(--radius-3xl);
  background: var(--background);
}

body.review-active .answer-panel:not(.is-revealed) > * {
  opacity: 0;
  visibility: hidden;
}

.answer-panel > * {
  transition: opacity var(--motion-base) var(--ease-out), filter var(--motion-base) ease;
}

.chinese-text {
  margin: 0;
  color: var(--fg-4);
  font-size: var(--text-display-zh);
  font-weight: 600;
  letter-spacing: 0;
  line-height: 105%;
  text-align: center;
}

.icon-button {
  display: inline-flex;
  min-height: 36px;
  align-items: center;
  justify-content: center;
  padding: 0 14px;
  border: 0;
  border-radius: var(--radius-pill);
  background: var(--sky-1);
  color: var(--sky-4);
  font-size: 14px;
  font-weight: 600;
}

.audio-button {
  align-self: center;
  justify-self: end;
  width: 44px;
  height: 44px;
  min-height: 44px;
  padding: 0;
  background: transparent;
  color: var(--fg-3);
}

.audio-button svg {
  width: 21px;
  height: 21px;
  fill: none;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.end-review {
  align-self: center;
  justify-self: start;
  width: 44px;
  height: 44px;
  min-height: 44px;
  max-height: 44px;
  padding: 0;
  background: transparent;
  color: var(--fg-3);
}

.end-review svg {
  width: 26px;
  height: 26px;
  fill: none;
  stroke: currentColor;
  stroke-width: 2.5;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.answer-panel {
  display: grid;
  gap: 8px;
  max-width: 628px;
  margin: 0 auto 24px;
  padding: 18px;
  border-radius: var(--radius-6);
  background: var(--bg-a1);
  text-align: center;
}

.answer-main,
.answer-sub,
.example {
  margin: 0;
}

.answer-main {
  color: var(--fg-4);
  font-size: 24px;
  font-weight: 600;
}

.answer-sub,
.example {
  color: var(--fg-3);
  font-size: 16px;
  line-height: 140%;
}

.review-actions {
  display: grid;
  gap: 10px;
  justify-content: stretch;
}

body.review-active .review-actions {
  position: fixed;
  right: 50%;
  bottom: 0;
  z-index: 60;
  width: 100%;
  padding: 12px max(20px, env(safe-area-inset-right)) 24px max(20px, env(safe-area-inset-left));
  background: color-mix(in srgb, var(--background) 96%, transparent);
  transform: translateX(50%);
  backdrop-filter: blur(16px);
}

body.review-active #reveal-answer,
body.review-active .rating-actions {
  width: min(100%, 628px);
  margin: 0 auto;
}

#reveal-answer {
  width: 100%;
  min-height: 56px;
  background: var(--purple-4);
  color: #ffffff;
  text-transform: none;
  letter-spacing: 0;
}

.rating-actions {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
  width: 100%;
}

.rating-actions .button {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 64px;
  padding: 0 12px;
  border-radius: var(--radius-6);
  transition: opacity var(--motion-base) ease, transform var(--motion-fast) var(--ease-out);
}

.rating-actions .button strong {
  font-size: 22px;
  font-weight: 600;
  line-height: 100%;
}

.rating-again {
  background: var(--rating-again-bg);
}

.rating-again strong {
  color: var(--rating-again-fg);
}

.rating-hard {
  background: var(--rating-hard-bg);
}

.rating-hard strong {
  color: var(--rating-hard-fg);
}

.rating-good {
  background: var(--rating-good-bg);
}

.rating-good strong {
  color: var(--rating-good-fg);
}

.rating-easy {
  background: var(--rating-easy-bg);
}

.rating-easy strong {
  color: var(--rating-easy-fg);
}

.section-heading {
  margin-bottom: 20px;
}

.filters {
  margin-bottom: 16px;
}

input,
select {
  min-height: 44px;
  border: 1px solid var(--bg-a2);
  border-radius: var(--radius-pill);
  background: var(--background);
  box-shadow: var(--shadow-1);
  color: var(--fg-4);
  font-size: 16px;
  font-weight: 500;
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
  transition: box-shadow var(--motion-base) ease, background-color var(--motion-base) ease;
}

input {
  min-width: min(100%, 320px);
  padding: 0 16px;
}

select {
  width: 100%;
  padding: 0 38px 0 16px;
  appearance: none;
}

input:focus,
select:focus,
button:focus-visible {
  outline: 2px solid var(--sky-4);
  outline-offset: 2px;
}

.card-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.browse-pagination {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  margin: 20px 0 4px;
}

.browse-pagination .icon-button {
  width: 40px;
  height: 40px;
  color: var(--fg-3);
  background: transparent;
}

.browse-pagination .icon-button:disabled {
  cursor: default;
  opacity: 0.34;
}

.browse-pagination svg {
  width: 20px;
  height: 20px;
  fill: none;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

#browse-page-input {
  width: 40px;
  height: 40px;
  min-width: 40px;
  padding: 0;
  border: 1px solid var(--bg-a2);
  border-radius: var(--radius-3);
  background: var(--background);
  box-shadow: none;
  color: var(--fg-4);
  font-size: var(--text-headline);
  font-weight: 600;
  line-height: var(--leading-headline);
  text-align: center;
  font-variant-numeric: tabular-nums;
  appearance: textfield;
}

#browse-page-input::-webkit-outer-spin-button,
#browse-page-input::-webkit-inner-spin-button {
  margin: 0;
  appearance: none;
}

.select-wrap {
  position: relative;
  display: inline-grid;
  min-width: 184px;
}

.select-icon {
  position: absolute;
  top: 50%;
  right: 14px;
  width: 18px;
  height: 18px;
  color: var(--fg-3);
  fill: none;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
  transform: translateY(-50%);
  pointer-events: none;
  transition: transform var(--motion-base) var(--ease-out), color var(--motion-base) ease;
}

.browse-card {
  display: grid;
  gap: 10px;
  padding: 18px;
  border: 1px solid var(--bg-a2);
  border-radius: var(--radius-6);
  background: var(--background);
  box-shadow: var(--shadow-1);
  transition: transform var(--motion-base) var(--ease-out), box-shadow var(--motion-base) ease, background-color var(--motion-base) ease;
}

.learn-intro {
  margin-bottom: 16px;
  padding: 16px 18px;
  border-radius: var(--radius-6);
  background: var(--purple-1);
}

.learn-intro p {
  margin: 0;
  color: var(--fg-3);
  font-size: 16px;
  font-weight: 500;
  line-height: 145%;
}

.learn-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  align-items: start;
  gap: 12px;
}

.learn-panel {
  display: grid;
  gap: 14px;
  padding: 18px 0 0;
  border: 1px solid var(--bg-a2);
  border-radius: var(--radius-6);
  background: var(--background);
  box-shadow: var(--shadow-1);
  overflow: hidden;
}

.learn-panel-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 0 18px;
}

.learn-panel h3 {
  margin: 0;
  color: var(--fg-4);
  font-size: 20px;
  font-weight: 600;
}

.learn-table {
  display: grid;
  overflow: hidden;
}

.learn-row {
  display: grid;
  grid-template-columns: 64px 88px minmax(0, 1fr) minmax(84px, auto);
  gap: 10px;
  align-items: center;
  padding: 10px 18px;
  border-bottom: 1px solid var(--bg-a2);
  color: var(--fg-3);
  font-size: 14px;
  font-weight: 500;
}

.learn-row:last-child {
  border-bottom: 0;
}

.learn-head {
  background: var(--bg-a1);
  color: var(--fg-2);
  font-size: 12px;
  font-weight: 600;
}

.learn-row strong {
  color: var(--fg-4);
  font-size: 26px;
  font-weight: 600;
  line-height: 100%;
}

.learn-test-control {
  display: inline-flex;
  align-items: center;
  min-height: 32px;
  padding: 0;
  border: 0;
  border-radius: var(--radius-pill);
  background: transparent;
  color: var(--fg-3);
  font-size: 14px;
  font-weight: 600;
}

.toggle-pill {
  position: relative;
  display: inline-flex;
  width: 52px;
  height: 32px;
  align-items: center;
  border-radius: var(--radius-pill);
  background: var(--bg-4);
  padding: 3px;
  transition: background-color var(--motion-base) ease;
}

.toggle-pill span {
  width: 26px;
  height: 26px;
  border-radius: var(--radius-pill);
  background: var(--background);
  box-shadow: var(--shadow-2);
  transition: transform var(--motion-base) var(--ease-out);
}

.learn-test-control.is-active .toggle-pill {
  background: var(--purple-4);
}

.learn-test-control.is-active .toggle-pill span {
  transform: translateX(20px);
}

#view-learn.is-testing .learn-row span:not([role="columnheader"]),
#view-learn.is-testing .concept-list span,
#view-learn.is-testing .concept-list code,
#view-learn.is-testing .mini-reference-grid span,
#view-learn.is-testing .panel-description {
  border-radius: var(--radius-3);
  background: var(--bg-a2);
  color: transparent;
  user-select: none;
}

.learn-builder {
  margin-top: 12px;
  padding: 18px 0 0;
}

.learn-note {
  margin: 0;
  padding: 0 18px 18px;
  color: var(--fg-3);
  font-size: 14px;
  font-weight: 500;
  line-height: 140%;
}

.browse-top {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
}

.browse-zh {
  margin: 0;
  color: var(--fg-4);
  font-size: 26px;
  font-weight: 600;
  letter-spacing: 0;
}

#word-day-zh,
#word-day-example-zh,
#card-zh,
#card-example-zh,
.browse-zh,
.learn-row strong,
.learn-row span:nth-child(4) {
  letter-spacing: 0;
}

.browse-en,
.browse-romanization {
  margin: 0;
  color: var(--fg-3);
  font-size: 16px;
}

.settings-list {
  display: grid;
  gap: 0;
  border-top: 1px solid var(--bg-4);
}

.settings-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 24px;
  align-items: center;
  min-height: 104px;
  padding: 22px 0;
  border-bottom: 1px solid var(--bg-4);
}

.settings-copy {
  display: grid;
  gap: 6px;
}

.settings-copy > span {
  color: var(--fg-4);
  font-size: 20px;
  font-weight: 600;
}

.settings-copy > small {
  max-width: 52ch;
  color: var(--fg-2);
  font-size: 16px;
  font-weight: 500;
  line-height: 140%;
}

.settings-control {
  display: flex;
  justify-content: flex-end;
  gap: 8px;
}

.settings-control input[type="number"] {
  min-width: 0;
  width: 140px;
}

#import-progress {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
}

.danger-zone {
  background: transparent;
}

.danger-zone #reset-progress {
  background: var(--danger-bg);
  border: 1px solid var(--danger-border);
  color: var(--danger-fg);
}

.import-error {
  margin: 8px 0 0;
  padding: 10px 12px;
  border-radius: var(--radius-3);
  background: var(--red-1);
  color: var(--danger-fg);
  font-size: var(--text-footnote);
  font-weight: 500;
  line-height: var(--leading-footnote);
}

@keyframes view-enter {
  from {
    opacity: 0;
    transform: translateY(6px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes review-enter {
  from {
    opacity: 0;
    transform: translateY(8px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes sheet-enter {
  from {
    opacity: 0;
    transform: translateY(100%);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes modal-enter {
  from {
    opacity: 0;
    transform: translateY(8px) scale(0.98);
  }

  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

@media (hover: hover) and (pointer: fine) {
  .button-secondary:hover,
  .audio-button:hover,
  .end-review:hover {
    background: var(--bg-a2);
  }

  .rating-actions .button:hover {
    opacity: 0.5;
  }

  .rating-again:hover {
    background: #f973161a;
  }

  .rating-hard:hover {
    background: #fbbf2429;
  }

  .rating-good:hover {
    background: #0ea5e921;
  }

  .rating-easy:hover {
    background: #84cc1626;
  }

  .audio-button:hover,
  .end-review:hover {
    color: var(--fg-4);
  }

  .browse-card:hover {
    transform: translateY(-1px);
    box-shadow: var(--shadow-2);
  }

  .danger-zone #reset-progress:hover,
  .danger-button:hover {
    background: var(--danger-bg-hover);
  }
}

button:focus-visible,
.icon-button:focus-visible,
.nav-tab:focus-visible {
  outline: 2px solid var(--purple-4);
  outline-offset: 2px;
}

@media (max-width: 760px) {
  .app-shell {
    padding: 18px max(12px, env(safe-area-inset-right)) 0 max(12px, env(safe-area-inset-left));
  }

  .nav-tab {
    min-width: 72px;
  }

  .bottom-nav::before {
    width: 72px;
  }

  .section-heading,
  .review-meta {
    align-items: stretch;
    flex-direction: column;
  }

  .section-heading,
  .review-meta {
    display: flex;
  }

  #view-learn .section-heading {
    flex-direction: row !important;
    align-items: center !important;
  }

  #view-learn .learn-test-control {
    flex: 0 0 auto;
  }

  main {
    padding-top: 8px;
  }

  .card-list {
    grid-template-columns: 1fr;
  }

  .learn-grid {
    grid-template-columns: 1fr;
  }

  .learn-panel {
    padding: 16px 0 0;
  }

  .learn-row {
    grid-template-columns: 48px 58px minmax(0, 1fr);
    gap: 8px;
    padding: 10px 18px;
  }

  .learn-row span:nth-child(4) {
    grid-column: 3;
    color: var(--fg-2);
  }

  .learn-head {
    display: none;
  }

  .settings-row {
    grid-template-columns: 1fr;
    gap: 14px;
    align-items: stretch;
  }

  .settings-control {
    justify-content: flex-start;
  }

  h1 {
    font-size: 34px;
  }

  .button {
    min-height: 44px;
  }

  .start-review-button {
    min-height: 52px;
  }

  .rating-actions {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 10px;
  }

  body.review-active .review-meta {
    grid-template-columns: 44px minmax(0, 1fr) 44px;
  }

  .counter-pill {
    min-width: 62px;
    min-height: 40px;
    font-size: 22px;
  }

  .counter-arrow {
    font-size: 18px;
  }

  .prompt-panel {
    min-height: 240px;
  }

  body.review-active .card-face {
    padding: 44px 0;
  }

  body.review-active #review-overlay {
    padding-bottom: 188px;
  }

  .split-actions .button,
  #import-progress-button {
    flex: 1;
  }

  input,
  select,
  .select-wrap {
    width: 100%;
  }

}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: 1ms !important;
    animation-duration: 1ms !important;
    animation-iteration-count: 1 !important;
  }

  .view.is-active,
  body.review-active #review-overlay {
    animation: none;
  }
}