:root {
  --bg: #f6f8f5;
  --fg: #24302a;
  --accent: #1f7a5c;
  --accent-dark: #175c45;
  --card-bg: #ffffff;
  --border: #dde5dc;
  --correct: #2e7d32;
  --incorrect: #c0392b;
  --mastery-new: #b0a999;
  --mastery-learning: #c0392b;
  --mastery-familiar: #d9a441;
  --mastery-mastered: #2e7d32;
  --radius: 12px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #171e1a;
    --fg: #eef2ec;
    --card-bg: #212a24;
    --border: #37453d;
  }
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: "Hiragino Sans", "Yu Gothic", "Noto Sans JP", system-ui, -apple-system, sans-serif;
  min-height: 100%;
}

.app-header {
  position: relative;
  max-width: 480px;
  margin: 0 auto;
  text-align: center;
  padding: 1.2rem 1rem 0.6rem;
}

.app-header h1 {
  margin: 0;
  font-size: 1.4rem;
  letter-spacing: 0.05em;
}

.icon-btn {
  background: none;
  border: none;
  color: var(--fg);
  cursor: pointer;
  padding: 0.4rem;
  display: flex;
  align-items: center;
  justify-content: center;
}

.icon-btn:hover, .icon-btn:focus-visible {
  color: var(--accent);
}

.icon-btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.settings-btn {
  position: absolute;
  top: 0.7rem;
  right: 0.8rem;
}

.hamburger-icon {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  width: 1.3rem;
  height: 0.9rem;
}

.hamburger-icon span {
  display: block;
  height: 2px;
  border-radius: 2px;
  background: currentColor;
}

/* --- Settings dialog --- */

.settings-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.4);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
  z-index: 100;
}

.settings-overlay.hidden { display: none; }

.settings-panel {
  width: 100%;
  max-width: 360px;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem 1.2rem 1.2rem;
}

.settings-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.4rem;
}

.settings-header h2 {
  margin: 0;
  font-size: 1.05rem;
}

.settings-header h2 span {
  display: block;
  font-size: 0.65rem;
  font-weight: normal;
  color: #8a9188;
  margin-top: 0.1rem;
}

.settings-header .icon-btn {
  font-size: 1.4rem;
  line-height: 1;
}

.settings-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.8rem;
  padding: 0.8rem 0;
  border-bottom: 1px solid var(--border);
}

.settings-row:last-child { border-bottom: none; }

.settings-row-column {
  flex-direction: column;
  align-items: stretch;
  gap: 0.5rem;
}

.settings-row-label {
  font-size: 0.9rem;
}

.settings-row-label span {
  display: block;
  font-size: 0.7rem;
  font-weight: normal;
  color: #8a9188;
  margin-top: 0.1rem;
}

.switch {
  position: relative;
  display: inline-block;
  flex-shrink: 0;
  width: 2.6rem;
  height: 1.5rem;
}

.switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

.switch-slider {
  position: absolute;
  inset: 0;
  background: var(--border);
  border-radius: 999px;
  cursor: pointer;
  transition: background 0.15s ease;
}

.switch-slider::before {
  content: '';
  position: absolute;
  width: 1.1rem;
  height: 1.1rem;
  left: 0.2rem;
  top: 0.2rem;
  background: #fff;
  border-radius: 50%;
  transition: transform 0.15s ease;
}

.switch input:checked + .switch-slider { background: var(--accent); }
.switch input:checked + .switch-slider::before { transform: translateX(1.1rem); }

.switch input:focus-visible + .switch-slider {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.settings-segmented {
  display: flex;
  gap: 0.4rem;
}

.segmented-btn {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.1rem;
  padding: 0.5rem 0.3rem;
  font-size: 0.9rem;
  font-weight: bold;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg);
  color: var(--fg);
  cursor: pointer;
}

.segmented-btn span {
  font-size: 0.6rem;
  font-weight: normal;
  color: #8a9188;
}

.segmented-btn:hover, .segmented-btn:focus-visible {
  border-color: var(--accent);
}

.segmented-btn.active {
  border-color: var(--accent);
  color: var(--accent);
}

.settings-install-btn {
  display: flex;
  align-items: baseline;
  gap: 0.4rem;
  align-self: flex-start;
  padding: 0.6rem 0.9rem;
  font-size: 0.9rem;
  font-weight: bold;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: transparent;
  color: var(--accent);
  cursor: pointer;
}

.settings-install-btn span {
  font-size: 0.7rem;
  font-weight: normal;
  color: #8a9188;
}

.settings-install-btn:hover, .settings-install-btn:focus-visible {
  border-color: var(--accent);
}

.settings-install-btn.hidden { display: none; }

.settings-install-hint {
  margin: 0;
  font-size: 0.75rem;
  line-height: 1.5;
  color: #8a9188;
}

.settings-install-hint.hidden { display: none; }

/* About section in Settings */
.about-app {
  margin: 0;
  font-size: 0.95rem;
  font-weight: bold;
}

.about-version {
  margin-left: 0.35rem;
  font-size: 0.75rem;
  font-weight: normal;
  color: #8a9188;
}

.about-link {
  align-self: flex-start;
  margin-top: 0.3rem;
  font-size: 0.85rem;
  font-weight: bold;
  color: var(--accent);
  text-decoration: none;
}

.about-link span {
  display: block;
  margin-top: 0.1rem;
  font-size: 0.7rem;
  font-weight: normal;
  color: #8a9188;
}

.about-link:hover,
.about-link:focus-visible {
  text-decoration: underline;
}

#app {
  max-width: 480px;
  margin: 0 auto;
  padding: 0.5rem 1rem 3rem;
}

.screen.hidden { display: none; }

.banner-warning, .banner-error {
  border-radius: var(--radius);
  padding: 0.8rem 1rem;
  margin-bottom: 1rem;
  font-size: 0.85rem;
  line-height: 1.5;
}

.banner-warning.hidden, .banner-error.hidden { display: none; }

.banner-warning {
  background: #fff3cd;
  border: 1px solid #f0d98c;
  color: #6b5900;
}

.banner-error {
  background: #fdecea;
  border: 1px solid #f3b7b0;
  color: #7a1f14;
}

.banner-warning code, .banner-error code {
  background: rgba(0,0,0,0.06);
  padding: 0.1em 0.35em;
  border-radius: 4px;
}

/* --- Home screen --- */

#screen-home h2 {
  text-align: center;
  margin-bottom: 0.2rem;
  font-size: 1.15rem;
}

.subtitle {
  text-align: center;
  color: #8a9188;
  margin-top: 0;
  font-size: 0.85rem;
}

.progress-heading {
  margin: 1rem 0 0.4rem;
  font-size: 0.85rem;
  color: #8a9188;
  text-align: center;
  letter-spacing: 0.05em;
}

.progress-heading span {
  display: block;
  font-size: 0.65rem;
  letter-spacing: normal;
  margin-top: 0.1rem;
}

.progress-summary {
  display: flex;
  justify-content: center;
  gap: 1.2rem;
  margin: 0.4rem 0 0;
  padding: 0.6rem 0.5rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--card-bg);
}

.progress-stat {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.1rem;
  font-size: 0.75rem;
  color: #8a9188;
}

.progress-stat strong {
  font-size: 1.1rem;
  color: var(--fg);
}

.context-progress-list {
  display: flex;
  flex-direction: column;
  margin-top: 0.4rem;
  padding: 0.2rem 0.7rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--card-bg);
}

.context-row {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.35rem 0;
}

.context-row:not(:last-child) {
  border-bottom: 1px solid var(--border);
}

.context-row-name {
  flex-shrink: 0;
  min-width: 4.4em;
  font-size: 0.8rem;
  color: var(--fg);
}

.context-row-percent,
.context-row-accuracy {
  flex-shrink: 0;
  min-width: 2.6em;
  font-variant-numeric: tabular-nums;
  font-size: 0.75rem;
  color: #8a9188;
  text-align: right;
}

.context-row[data-status="new"] .progress-bar-fill { background: var(--mastery-new); }
.context-row[data-status="learning"] .progress-bar-fill { background: var(--mastery-learning); }
.context-row[data-status="familiar"] .progress-bar-fill { background: var(--mastery-familiar); }
.context-row[data-status="mastered"] .progress-bar-fill { background: var(--mastery-mastered); }

.context-row-reset {
  flex-shrink: 0;
  width: 1.4rem;
  height: 1.4rem;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0;
  font-size: 0.9rem;
  line-height: 1;
  border: none;
  border-radius: 50%;
  background: transparent;
  color: #8a9188;
  cursor: pointer;
}

.context-row-reset:hover, .context-row-reset:focus-visible {
  color: var(--accent);
  outline: none;
}

.progress-mode-breakdown {
  margin: 0.4rem 0 0;
  padding: 0.4rem 0.7rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--card-bg);
}

.progress-mode-row {
  display: flex;
  justify-content: space-between;
  gap: 0.6rem;
  padding: 0.15rem 0;
  font-size: 0.8rem;
  color: #8a9188;
}

.progress-mode-row:not(:last-child) {
  border-bottom: 1px solid var(--border);
}

.progress-mode-label {
  font-weight: bold;
  color: var(--fg);
}

.progress-history {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  margin: 0.6rem 0 0;
  padding: 0.4rem 0.7rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--card-bg);
}

.progress-history-label {
  flex-shrink: 0;
  font-size: 0.75rem;
  color: #8a9188;
}

.progress-history-label span {
  display: block;
  font-size: 0.6rem;
}

.progress-history-bar {
  flex: 1;
  display: flex;
  flex-wrap: wrap;
  gap: 0.2rem;
}

.progress-history-bar.is-empty::after {
  content: '—';
  color: #8a9188;
  font-size: 0.8rem;
}

.history-dot {
  width: 0.5rem;
  height: 0.5rem;
  border-radius: 50%;
  background: var(--border);
}

.history-dot.correct { background: var(--correct); }
.history-dot.wrong { background: var(--incorrect); }

.mastery-dot {
  width: 0.5rem;
  height: 0.5rem;
  border-radius: 50%;
  flex-shrink: 0;
}

.mastery-dot.mastery-new { background: var(--mastery-new); }
.mastery-dot.mastery-learning { background: var(--mastery-learning); }
.mastery-dot.mastery-familiar { background: var(--mastery-familiar); }
.mastery-dot.mastery-mastered { background: var(--mastery-mastered); }

.progress-bar {
  flex: 1;
  height: 0.5rem;
  border-radius: 999px;
  background: var(--border);
  overflow: hidden;
}

.progress-bar-fill {
  height: 100%;
  background: var(--accent);
  border-radius: 999px;
  transition: width 0.2s ease;
}

/* Pill toggle rows: mode (Reading/Meaning/Fill-in-blank) and scope
   (Word only/In a sentence) both live on the front page, like kanji-drill's
   mode toggle sitting above its grade grid — picking one just relabels the
   context grid below rather than navigating to another screen. */
.toggle-row {
  display: flex;
  gap: 0.6rem;
  justify-content: center;
  margin-top: 1rem;
}

.toggle-row.hidden { display: none; }

.toggle-btn {
  position: relative;
  flex: 1;
  max-width: 180px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.15rem;
  padding: 0.6rem 0.5rem;
  font-size: 1rem;
  font-weight: bold;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--card-bg);
  color: var(--fg);
  cursor: pointer;
}

.toggle-btn span {
  font-size: 0.7rem;
  font-weight: normal;
  color: #8a9188;
}

.toggle-btn.active {
  border-color: var(--accent);
  color: var(--accent);
}

.toggle-btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.context-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.8rem;
  margin-top: 0.8rem;
}

.context-btn {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.3rem;
  padding: 1.3rem 0.5rem;
  font-size: 1.05rem;
  font-weight: bold;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--card-bg);
  color: var(--fg);
  cursor: pointer;
  transition: transform 0.1s ease, box-shadow 0.15s ease;
}

.context-btn span {
  font-size: 0.7rem;
  font-weight: normal;
  color: #8a9188;
}

.context-btn:hover, .context-btn:focus-visible {
  border-color: var(--accent);
  box-shadow: 0 2px 8px rgba(0,0,0,0.08);
}

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

/* --- Quiz screen --- */

.quiz-topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin: 0.8rem 0 1.2rem;
}

.quiz-progress {
  font-variant-numeric: tabular-nums;
  color: #8a9188;
  font-size: 0.9rem;
}

.quiz-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem 1.2rem 1.5rem;
  text-align: center;
}

.quiz-word {
  font-size: 2.6rem;
  line-height: 1.3;
  margin-bottom: 0.3rem;
}

.quiz-word.is-sentence {
  font-size: 1.7rem;
  line-height: 1.7;
}

.quiz-sentence-target {
  color: var(--accent);
  font-weight: bold;
}

.quiz-blank {
  color: var(--accent);
  font-weight: bold;
  letter-spacing: 0.1em;
}

/* Furigana, shown above kanji via <ruby>/<rt> — as Meaning mode's togglable
   reading hint (pre-answer), or as the revealed reading once a Reading- or
   Fill-in-blank question is answered. The sentence line already reserves
   space above it (is-sentence line-height), so adding ruby doesn't shift
   the rest of the card. */
.quiz-word rt {
  font-size: 0.4em;
  font-weight: normal;
  color: var(--accent);
}

/* Meaning mode's hint toggle hides the <rt> rather than removing it, so the
   reserved line-height above the word doesn't jump when the setting flips. */
.quiz-word.hide-hint rt {
  visibility: hidden;
}

.quiz-hint {
  color: #8a9188;
  font-size: 1rem;
  font-style: italic;
  margin: 0 0 1rem;
}

.quiz-hint.hidden { display: none; }

.quiz-instruction {
  color: #8a9188;
  font-size: 0.9rem;
  margin: 0 0 1.2rem;
}

.quiz-instruction span {
  display: block;
  font-size: 0.7rem;
  margin-top: 0.15rem;
}

.quiz-options {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.7rem;
}

/* Manual-continue hint shown after answering when auto-advance is off. The
   whole document is clickable to continue; this is a cue, not the only target. */
.quiz-continue {
  margin: 1rem 0 0;
  text-align: center;
  font-size: 1rem;
  font-weight: bold;
  color: var(--accent);
  cursor: pointer;
  animation: quiz-continue-fade 0.2s ease-in;
}

.quiz-continue span {
  display: block;
  font-size: 0.7rem;
  font-weight: normal;
  color: #8a9188;
  margin-top: 0.15rem;
}

.quiz-continue.hidden { display: none; }

@keyframes quiz-continue-fade {
  from { opacity: 0; }
  to { opacity: 1; }
}

/* "Weak spot" marker for a leech (an item the learner keeps missing). Subtle,
   amber, self-explaining — signals the hint is shown as extra help. */
.quiz-leech-badge {
  display: inline-block;
  margin: 0 auto 0.6rem;
  padding: 0.1rem 0.55rem;
  font-size: 0.75rem;
  font-weight: bold;
  color: #9a6a00;
  background: #fdf0d5;
  border: 1px solid #e6c886;
  border-radius: 999px;
}

.quiz-leech-badge span {
  font-weight: normal;
  font-size: 0.65rem;
  margin-left: 0.3rem;
  opacity: 0.8;
}

.quiz-leech-badge.hidden { display: none; }

.option-btn {
  position: relative;
  /* Symmetric side gutter reserves room for the corner key-badge so long
     readings never sit under it, while keeping the text optically centered. */
  padding: 0.9rem 1.7rem;
  font-size: 1.05rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg);
  color: var(--fg);
  cursor: pointer;
}

.key-badge {
  display: inline-flex;
  flex-shrink: 0;
  align-items: center;
  justify-content: center;
  width: 1.1rem;
  height: 1.1rem;
  font-size: 0.65rem;
  font-variant-numeric: tabular-nums;
  color: #8a9188;
  border: 1px solid var(--border);
  border-radius: 4px;
}

.key-badge-corner {
  position: absolute;
  bottom: 0.35rem;
  left: 0.45rem;
}

/* Shortcut hint: a key-badge kept hidden until its button is hovered or
   keyboard-focused, for the mode/scope buttons whose label doesn't otherwise
   show the shortcut key. Gated to hover-capable pointer devices — a touch user
   has no keyboard key to hint at, and since it's absolutely positioned it
   reserves no space, so it simply never appears there. */
.shortcut-hint {
  opacity: 0;
  transition: opacity 0.12s ease;
}

@media (hover: hover) {
  .mode-btn:hover .shortcut-hint,
  .mode-btn:focus-visible .shortcut-hint,
  .toggle-btn:hover .shortcut-hint,
  .toggle-btn:focus-visible .shortcut-hint,
  .review-btn:hover .shortcut-hint,
  .review-btn:focus-visible .shortcut-hint {
    opacity: 1;
  }
}

.option-btn.correct .key-badge,
.option-btn.incorrect .key-badge {
  color: inherit;
  border-color: rgba(255, 255, 255, 0.6);
}

.option-btn:hover, .option-btn:focus-visible {
  border-color: var(--accent);
}

.option-btn.correct {
  background: var(--correct);
  border-color: var(--correct);
  color: #fff;
}

.option-btn.incorrect {
  background: var(--incorrect);
  border-color: var(--incorrect);
  color: #fff;
}

.option-btn:disabled {
  cursor: default;
  opacity: 0.9;
}

/* --- Summary screen --- */

#screen-summary {
  text-align: center;
}

.summary-score {
  font-size: 1.4rem;
  font-weight: bold;
}

.summary-score span {
  display: block;
  font-size: 0.7rem;
  font-weight: normal;
  color: #8a9188;
}

.summary-missed {
  text-align: left;
  margin: 1rem 0;
}

.summary-missed h3 {
  font-size: 0.95rem;
  color: #8a9188;
}

.missed-item {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 0.5rem;
  padding: 0.5rem 0.2rem;
  border-bottom: 1px solid var(--border);
  font-size: 1.05rem;
}

.missed-item-meaning {
  flex: 1;
  color: #8a9188;
  font-size: 0.85rem;
  font-style: italic;
  text-align: center;
}

.summary-correct {
  text-align: left;
  margin: 1rem 0;
}

.summary-correct-details summary {
  cursor: pointer;
  font-size: 0.95rem;
  color: #8a9188;
  padding: 0.3rem 0;
}

.summary-correct-details[open] summary {
  margin-bottom: 0.3rem;
}

.summary-actions {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
  margin-top: 1.5rem;
}

.primary-btn {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.15rem;
  padding: 0.9rem;
  font-size: 1.05rem;
  font-weight: bold;
  border: none;
  border-radius: var(--radius);
  background: var(--accent);
  color: #fff;
  cursor: pointer;
}

.primary-btn:hover { background: var(--accent-dark); }

.primary-btn:focus-visible,
.secondary-btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.primary-btn .key-badge {
  border-color: rgba(255, 255, 255, 0.6);
  color: #fff;
}

.primary-btn span {
  font-size: 0.7rem;
  font-weight: normal;
  color: rgba(255, 255, 255, 0.75);
}

.secondary-btn {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.15rem;
  padding: 0.9rem;
  font-size: 1.05rem;
  font-weight: bold;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: transparent;
  color: var(--accent);
  cursor: pointer;
}

.secondary-btn:hover { border-color: var(--accent); }

.secondary-btn span {
  font-size: 0.7rem;
  font-weight: normal;
  color: #8a9188;
}

.link-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  background: none;
  border: none;
  color: var(--accent);
  font-size: 0.95rem;
  cursor: pointer;
  padding: 0.4rem;
}

.link-btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

@media (min-width: 480px) {
  .quiz-word { font-size: 3rem; }
}