:root {
  --paper: #F7F7F4;
  --white: #FFFFFF;
  --ink: #101010;
  --ink-soft: #444444;
  --muted: #8A8A85;
  --hairline: #D9D9D3;
  --punch: #FF4D00;
  --sans: "Hiragino Sans", "Noto Sans JP", -apple-system, sans-serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

/* the hidden attribute must always win over display rules like .card-back { display: flex } */
[hidden] { display: none !important; }

html { background: var(--paper); }

body {
  font-family: var(--sans);
  color: var(--ink);
  line-height: 1.7;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
}

a { color: var(--ink); text-decoration: none; }

button { font-family: inherit; cursor: pointer; }

:focus-visible { outline: 3px solid var(--punch); outline-offset: 2px; }

/* ---------- masthead ---------- */

.site-header {
  background: var(--ink);
  color: var(--paper);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.75rem 1.25rem;
}

.wordmark { display: inline-flex; align-items: center; gap: 0.6rem; color: var(--paper); }

.wordmark-text {
  font-weight: 900;
  font-size: 1.15rem;
  letter-spacing: 0.04em;
}

.hanko {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1.7rem;
  height: 1.7rem;
  background: var(--punch);
  color: #fff;
  font-size: 0.95rem;
  font-weight: 900;
}

.site-nav { display: flex; gap: 1.3rem; font-size: 0.88rem; }

.site-nav a { color: #9C9C97; font-weight: 800; letter-spacing: 0.12em; }

.site-nav a.active { color: var(--paper); border-bottom: 3px solid var(--punch); }

.due-badge {
  display: inline-block;
  min-width: 1.4em;
  text-align: center;
  background: var(--punch);
  color: #fff;
  font-size: 0.7rem;
  font-weight: 900;
  padding: 0.08em 0.4em;
  vertical-align: 0.18em;
}

/* ---------- layout ---------- */

.view {
  flex: 1;
  width: 100%;
  max-width: 46rem;
  margin: 0 auto;
  padding: 1.6rem 1.25rem 3.5rem;
}

/* review: bigger stage, card block vertically centered in the viewport */
.view.center-view {
  display: flex;
  flex-direction: column;
  justify-content: center;
  max-width: 56rem;
  padding-bottom: 2.5rem;
}

.center-view .bigcard { min-height: 21rem; padding: 3.2rem 2.2rem 2.6rem; }

.center-view .card-front.is-sentence { font-size: 1.6rem; }

.center-view .sentence-answer { font-size: 2rem; }

.center-view .card-back .meaning { font-size: 1.15rem; }

.center-view .breakdown li { font-size: 0.92rem; }

.center-view .card-back .breakdown,
.center-view .card-back .gex-line,
.center-view .card-back .detail { max-width: 36rem; }

/* ---------- bilingual UI text ---------- */

.jaline-ja {
  border: none;
  background: none;
  padding: 0;
  font: inherit;
  color: inherit;
  cursor: pointer;
  display: inline-block;
}

.jaline-ja:hover { color: var(--punch); }

.jaline-zh { color: var(--muted); font-size: 0.78rem; font-weight: 600; margin-top: 0.1rem; }

.today-hero .jaline { margin-top: 0.2rem; }

.btn-zh { display: block; font-size: 0.68rem; font-weight: 700; letter-spacing: 0.15em; opacity: 0.72; margin-top: 0.1rem; }

/* ---------- unlearned-material planner ---------- */

.learn-progress { margin-top: 1.4rem; }

.lp-bar { height: 8px; background: var(--hairline); }

.lp-fill { height: 100%; background: var(--ink); }

.lp-text { color: var(--ink-soft); font-size: 0.8rem; font-weight: 600; margin-top: 0.35rem; text-align: center; }

.site-footer {
  background: var(--ink);
  text-align: center;
  padding: 1.1rem 0 1.2rem;
}

.footer-tagline { color: var(--paper); font-size: 0.78rem; font-weight: 800; letter-spacing: 0.18em; }

.footer-legal { color: #6E6E6A; font-size: 0.68rem; font-weight: 600; letter-spacing: 0.08em; margin-top: 0.25rem; }

.sync-link {
  border: none;
  background: none;
  color: #6E6E6A;
  font: inherit;
  cursor: pointer;
  text-decoration: underline dotted;
}

.sync-link:hover { color: var(--paper); }

.page-title { font-size: 1.9rem; font-weight: 900; letter-spacing: -0.02em; line-height: 1.3; margin-bottom: 0.9rem; }

.empty-note { color: var(--muted); text-align: center; padding: 3rem 0; }

.note-link { display: inline-block; margin-top: 1.6rem; font-weight: 800; border-bottom: 3px solid var(--punch); }

/* ---------- section openers ---------- */

.section-chip {
  display: block;
  font-size: 1.5rem;
  font-weight: 900;
  letter-spacing: -0.01em;
  border-bottom: 4px solid var(--ink);
  padding-bottom: 0.15rem;
  margin: 2.6rem 0 1.1rem;
}

.section-chip:first-of-type { margin-top: 0.4rem; }

.section-chip .count {
  color: var(--punch);
  font-size: 0.85rem;
  font-weight: 900;
  margin-left: 0.7em;
  vertical-align: 0.5em;
  letter-spacing: 0.05em;
}

/* ---------- today ---------- */

.today-hero { padding: 1.6rem 0 1.4rem; }

.today-label {
  display: block;
  color: var(--punch);
  font-size: 0.78rem;
  font-weight: 900;
  letter-spacing: 0.35em;
}

.today-big { line-height: 1.05; margin: 0.2rem 0 0.4rem; }

.today-count { font-size: 6rem; font-weight: 900; letter-spacing: -0.05em; font-variant-numeric: tabular-nums; }

.today-unit { font-size: 1.6rem; font-weight: 800; margin-left: 0.1em; }

.today-done-big { font-size: 2.1rem; font-weight: 900; letter-spacing: -0.02em; padding: 0.8rem 0 0.3rem; }

.today-sub { color: var(--ink-soft); font-size: 0.92rem; font-weight: 600; border-top: 4px solid var(--ink); padding-top: 0.5rem; }

.start-btn {
  display: block;
  margin-top: 1.5rem;
  background: var(--punch);
  color: #fff;
  text-align: center;
  font-size: 1.15rem;
  font-weight: 900;
  letter-spacing: 0.4em;
  padding: 0.95rem 0 0.95rem 0.4em;
}

.start-btn:hover { background: var(--ink); }

.start-btn:active { transform: translateY(1px); }

/* stamp calendar: an editorial grid */

.stamp-card { border: 2px solid var(--ink); background: var(--white); margin-top: 1.8rem; }

.stamp-month {
  display: flex;
  align-items: baseline;
  gap: 1rem;
  font-size: 0.85rem;
  font-weight: 900;
  letter-spacing: 0.25em;
  background: var(--ink);
  color: var(--paper);
  padding: 0.3rem 0.9rem;
}

.streak { color: var(--punch); font-size: 0.78rem; letter-spacing: 0.05em; }

.stamp-grid {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 1px;
  background: var(--hairline);
  border-top: 2px solid var(--ink);
}

.stamp-day {
  aspect-ratio: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--white);
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
}

.stamp-day.today { box-shadow: inset 0 0 0 2px var(--ink); color: var(--ink); font-weight: 900; }

.stamp-day.stamped {
  background: var(--punch);
  color: #fff;
  font-weight: 900;
  font-size: 0.95rem;
}

/* clock line: quiet, tappable date and time */

.clock-line {
  margin-top: 1.1rem;
  text-align: center;
  border-top: 1px solid var(--hairline);
  padding-top: 0.7rem;
}

.clock-row { display: inline-flex; align-items: baseline; gap: 0.5rem; }

.clock-seg {
  border: none;
  background: none;
  color: var(--ink-soft);
  font-size: 0.88rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  font-variant-numeric: tabular-nums;
  padding: 0.1rem 0.15rem;
  border-bottom: 2px dotted var(--hairline);
}

.clock-seg:hover { color: var(--punch); border-bottom-color: var(--punch); }

.clock-sep { color: var(--muted); font-size: 0.8rem; }

.clock-kana { color: var(--muted); font-size: 0.82rem; margin-top: 0.35rem; letter-spacing: 0.04em; }

/* ---------- lesson list ---------- */

.lesson-list { list-style: none; border-top: 4px solid var(--ink); }

.lesson-list li { border-bottom: 1px solid var(--hairline); }

.lesson-link {
  display: flex;
  align-items: baseline;
  gap: 1rem;
  flex-wrap: wrap;
  padding: 1.1rem 0.2rem;
}

.lesson-link:hover .lesson-title { color: var(--punch); }

.lesson-date {
  font-variant-numeric: tabular-nums;
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  white-space: nowrap;
}

.lesson-title { font-weight: 900; font-size: 1.25rem; letter-spacing: -0.01em; }

.lesson-counts { margin-left: auto; color: var(--muted); font-size: 0.75rem; font-weight: 700; white-space: nowrap; }

/* ---------- vocab entries ---------- */

.grid { display: block; border-top: 1px solid var(--hairline); }

@media (min-width: 640px) {
  .grid:not(.grid-wide) { columns: 2; column-gap: 2.2rem; column-rule: 1px solid var(--hairline); }
}

.tcard {
  break-inside: avoid;
  padding: 0.5rem 0.1rem;
  border-bottom: 1px solid var(--hairline);
}

.word { font-size: 1.25rem; font-weight: 900; line-height: 1.55; letter-spacing: -0.01em; }

.word ruby rt { font-size: 0.56rem; font-weight: 500; color: var(--ink-soft); }

.word.pattern { font-size: 1.2rem; }

.mean { display: inline; color: var(--ink-soft); font-size: 0.85rem; font-weight: 500; margin-left: 0.6em; }

.note { color: var(--muted); font-size: 0.82rem; padding-left: 1em; }

.note::before { content: "→ "; color: var(--punch); font-weight: 900; }

/* per-sentence grammar breakdown */

.breakdown {
  list-style: none;
  margin-top: 0.45rem;
  border-left: 4px solid var(--punch);
  background: var(--paper);
  padding: 0.45rem 0.85rem;
}

.breakdown li {
  font-size: 0.84rem;
  color: var(--ink-soft);
  line-height: 1.8;
  padding-left: 1em;
  text-indent: -1em;
}

.breakdown li::before { content: "・"; color: var(--punch); font-weight: 900; }

.card-back .breakdown { text-align: left; max-width: 30rem; width: 100%; }

/* grammar 讲解 block */
.detail {
  font-size: 0.85rem;
  color: var(--ink-soft);
  background: var(--paper);
  border-left: 4px solid var(--punch);
  padding: 0.5rem 0.85rem;
  margin: 0.55rem 0 0.4rem;
  line-height: 1.85;
}

/* grammar: boxed features */
.grid-wide { display: block; border-top: none; }

.grid-wide .tcard {
  background: var(--white);
  border: 2px solid var(--ink);
  padding: 1rem 1.15rem 0.9rem;
  margin-bottom: 1.1rem;
}

.gex-line { display: flex; align-items: flex-start; gap: 0.6rem; margin-top: 0.55rem; }

.gex-line .speak { margin-top: 0.15rem; }

.gex-body { min-width: 0; }

.gex { font-size: 0.98rem; font-weight: 700; }

.gex-zh { color: var(--muted); font-size: 0.82rem; }

.tcard-foot { display: inline-flex; align-items: center; gap: 0.4rem; margin-left: 0.4em; vertical-align: middle; }

.kind { display: none; }

/* pitch accent: punch-orange overline, tick on the drop */

.pitch { display: inline-flex; align-items: baseline; font-size: 0.9rem; font-weight: 500; margin-left: 0.5em; }

.pitch .mora { padding: 0.1em 0.02em; border-top: 2.5px solid transparent; }

.pitch .hi { border-top-color: var(--punch); }

.pitch .drop { border-right: 2.5px solid var(--punch); }

.accent-num { color: var(--punch); font-size: 0.68rem; font-weight: 900; vertical-align: super; margin-left: 0.2em; }

/* ---------- speak button ---------- */

.speak {
  border: 2px solid var(--ink);
  background: var(--white);
  color: var(--ink);
  width: 1.9rem;
  height: 1.9rem;
  font-size: 0.78rem;
  line-height: 1;
  flex-shrink: 0;
  vertical-align: middle;
}

.speak:hover { background: var(--ink); color: var(--white); }

.speak:active { transform: scale(0.94); }

/* ---------- sentences ---------- */

.sentence-list { list-style: none; border-top: 1px solid var(--hairline); }

.sentence-list li {
  display: flex;
  align-items: flex-start;
  gap: 0.7rem;
  padding: 0.65rem 0.1rem;
  border-bottom: 1px solid var(--hairline);
}

.sentence-ja { font-size: 1.05rem; font-weight: 700; }

.sentence-en { color: var(--muted); font-size: 0.82rem; }

/* ---------- lesson detail header ---------- */

.lesson-head { border-bottom: 4px solid var(--ink); padding-bottom: 0.6rem; margin-bottom: 0.4rem; }

.lesson-head .page-title { margin-bottom: 0; }

.lesson-head .lesson-date { display: block; }

.back-link { font-size: 0.8rem; font-weight: 800; letter-spacing: 0.1em; display: inline-block; margin-bottom: 1.1rem; color: var(--punch); }

/* ---------- review ---------- */

.progress { height: 6px; background: var(--hairline); margin-bottom: 0.7rem; }

.progress-fill { height: 100%; background: var(--punch); transition: width 0.25s ease; }

.review-status { color: var(--muted); font-size: 0.78rem; font-weight: 800; letter-spacing: 0.2em; text-align: center; margin-bottom: 1.1rem; }

.bigcard {
  background: var(--white);
  border: 2px solid var(--ink);
  padding: 2.8rem 1.5rem 2.4rem;
  text-align: center;
  min-height: 16rem;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 1rem;
}

.card-front { font-size: 2.7rem; font-weight: 900; letter-spacing: -0.02em; line-height: 1.4; }

.card-front.is-grammar { font-size: 1.8rem; }

.card-front.is-sentence { font-size: 1.35rem; font-weight: 800; line-height: 1.7; }

.card-hint { color: var(--muted); font-size: 0.78rem; font-weight: 700; letter-spacing: 0.25em; }

.card-tag {
  align-self: center;
  color: var(--punch);
  font-size: 0.72rem;
  font-weight: 900;
  letter-spacing: 0.45em;
  padding-left: 0.45em;
}

.card-back { display: flex; flex-direction: column; gap: 0.55rem; align-items: center; }

.card-back .pitch { font-size: 1.3rem; margin-left: 0; }

.card-back .meaning { font-size: 1rem; color: var(--ink-soft); font-weight: 600; }

.card-back .example { color: var(--ink-soft); font-size: 0.95rem; font-weight: 600; }

.card-back .detail { text-align: left; max-width: 30rem; }

.card-back .gex-line { text-align: left; max-width: 30rem; width: 100%; justify-content: center; }

.sentence-answer { font-size: 1.7rem; font-weight: 900; line-height: 1.55; letter-spacing: -0.01em; }

.reveal-btn {
  margin-top: 1.4rem;
  width: 100%;
  border: none;
  background: var(--ink);
  color: var(--paper);
  font-size: 0.95rem;
  font-weight: 900;
  letter-spacing: 0.45em;
  padding: 0.9rem 0 0.9rem 0.45em;
}

.reveal-btn:hover { background: var(--punch); }

.reveal-btn:active { transform: translateY(1px); }

.grade-row {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  margin-top: 1.4rem;
  border: 2px solid var(--ink);
  background: var(--ink);
  gap: 2px;
}

.grade-btn {
  border: none;
  background: var(--white);
  color: var(--ink);
  padding: 0.8rem 0.2rem;
  font-size: 0.92rem;
  font-weight: 900;
}

.grade-btn:hover { background: var(--paper); }

.grade-btn:active { transform: none; background: var(--hairline); }

.b-again { background: var(--punch); color: #fff; }

.b-again:hover { background: #E04400; }

.b-good:hover { background: var(--ink); color: #fff; }

/* ---------- review done ---------- */

.review-done { text-align: center; padding: 3.5rem 0; }

.combo { color: var(--punch); font-weight: 900; letter-spacing: 0.05em; }

.bonus-btn {
  display: inline-block;
  margin-top: 1.6rem;
  border: 2px solid var(--ink);
  background: var(--white);
  color: var(--ink);
  font-size: 0.95rem;
  font-weight: 900;
  letter-spacing: 0.15em;
  padding: 0.75rem 2.2rem;
  cursor: pointer;
}

.bonus-btn:hover { background: var(--punch); border-color: var(--punch); color: #fff; }

.review-done .bonus-btn { display: block; margin: 1.8rem auto 0; }

.review-done .note-link { margin-top: 1.1rem; }

/* confetti burst on completion */

.confetti { position: fixed; inset: 0; pointer-events: none; overflow: hidden; z-index: 99; }

.confetti-bit {
  position: absolute;
  top: -3vh;
  width: 10px;
  height: 16px;
  animation: confetti-fall linear forwards;
}

@keyframes confetti-fall {
  to { top: 105vh; transform: rotate(660deg); }
}

.big-stamp {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 6rem;
  height: 6rem;
  background: var(--punch);
  color: #fff;
  font-size: 2.6rem;
  font-weight: 900;
  transform: rotate(-8deg);
  margin-bottom: 1.3rem;
  animation: stamp-in 0.35s cubic-bezier(0.2, 1.6, 0.4, 1);
}

@keyframes stamp-in {
  from { transform: rotate(-8deg) scale(2.1); opacity: 0; }
  to { transform: rotate(-8deg) scale(1); opacity: 1; }
}

.done-title { font-size: 1.9rem; font-weight: 900; letter-spacing: -0.02em; }

.review-done .sub { color: var(--muted); font-size: 0.88rem; font-weight: 600; margin-top: 0.6rem; }

/* ---------- responsive & a11y ---------- */

@media (max-width: 480px) {
  .today-count { font-size: 4.4rem; }
  .card-front { font-size: 2.1rem; }
  .grade-row { grid-template-columns: repeat(2, 1fr); }
}

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