:root {
  --paper: #f1efe9;
  --paper-deep: #e8e2d5;
  --card: #fffdf8;
  --white: #ffffff;
  --ink: #242422;
  --muted: #6f6a61;
  --line: #d9d2c3;
  --indigo: #3d5a80;
  --indigo-dark: #2f4765;
  --sage: #6d8261;
  --sage-soft: #e6ebdf;
  --mustard: #d9a441;
  --danger: #a4473f;
  --shadow: 0 10px 30px rgba(61, 55, 42, 0.07);
  --radius: 14px;
  --serif: "Hiragino Mincho ProN", "Yu Mincho", "Noto Serif CJK TC", "Songti TC", serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans TC", "PingFang TC", sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 85% 4%, rgba(217, 164, 65, 0.08), transparent 18rem),
    var(--paper);
  font-family: var(--sans);
  line-height: 1.6;
}
body::before {
  content: "語";
  position: fixed;
  right: -0.18em;
  top: 11rem;
  z-index: -1;
  color: rgba(61, 90, 128, 0.045);
  font-family: var(--serif);
  font-size: clamp(16rem, 34vw, 30rem);
  line-height: 1;
  pointer-events: none;
}
button, input { font: inherit; }
button { cursor: pointer; }
button:focus-visible, a:focus-visible { outline: 3px solid rgba(217, 164, 65, 0.75); outline-offset: 3px; }
.svg-sprite { display: none; }
.icon { width: 1.15rem; height: 1.15rem; fill: none; stroke: currentColor; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; vertical-align: -0.2rem; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.8rem clamp(1rem, 4vw, 3rem);
  border-bottom: 1px solid rgba(61, 90, 128, 0.16);
  background: rgba(241, 239, 233, 0.94);
  backdrop-filter: blur(14px);
}
.brand { display: inline-flex; align-items: center; gap: 0.75rem; color: var(--ink); text-decoration: none; }
.brand-mark {
  display: grid;
  place-items: center;
  width: 2.65rem;
  height: 2.65rem;
  border: 1.5px solid var(--indigo);
  border-radius: 50%;
  color: var(--indigo);
  font-family: var(--serif);
  font-size: 1.35rem;
}
.brand strong { display: block; letter-spacing: 0.14em; line-height: 1.1; }
.brand small { display: block; color: var(--muted); font-family: var(--serif); letter-spacing: 0.18em; }
.main-nav { display: flex; gap: 0.2rem; overflow-x: auto; scrollbar-width: none; }
.main-nav::-webkit-scrollbar { display: none; }
.main-nav button {
  border: 0;
  border-bottom: 2px solid transparent;
  background: transparent;
  color: var(--muted);
  padding: 0.55rem 0.7rem;
  white-space: nowrap;
}
.main-nav button.active { color: var(--indigo); border-bottom-color: var(--mustard); font-weight: 700; }

.app-shell { width: min(1180px, calc(100% - 2rem)); margin: 0 auto; padding: 2rem 0 4rem; }
.page-head { position: relative; margin: 1rem 0 1.5rem; }
.eyebrow { color: var(--sage); font-size: 0.78rem; font-weight: 800; letter-spacing: 0.22em; text-transform: uppercase; }
.page-head h1, .hero h1 { margin: 0.2rem 0 0.5rem; font-family: var(--serif); font-size: clamp(2.2rem, 6vw, 4.8rem); line-height: 1.12; font-weight: 600; }
.page-head p, .hero p { max-width: 720px; color: var(--muted); }
.jp-display { font-family: var(--serif); }

.card {
  position: relative;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--card);
  box-shadow: var(--shadow);
  padding: clamp(1rem, 3vw, 1.6rem);
  overflow: hidden;
}
.card h2, .card h3 { margin-top: 0; }
.muted { color: var(--muted); }
.small { font-size: 0.9rem; }
.section { margin-top: 1.5rem; }
.section-title { display: flex; align-items: end; justify-content: space-between; gap: 1rem; margin: 2rem 0 0.9rem; }
.section-title h2 { margin: 0; font-family: var(--serif); font-size: clamp(1.55rem, 3vw, 2.2rem); }
.section-title p { margin: 0; color: var(--muted); }

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.45fr) minmax(280px, 0.75fr);
  gap: 1.2rem;
  align-items: stretch;
}
.hero-main { min-height: 320px; display: flex; flex-direction: column; justify-content: flex-end; }
.hero-main::after {
  content: attr(data-watermark);
  position: absolute;
  right: 0.3rem;
  top: -2.3rem;
  color: rgba(61, 90, 128, 0.06);
  font-family: var(--serif);
  font-size: 11rem;
  line-height: 1;
}
.hero-stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 0.7rem; margin-top: 1.4rem; }
.stat { border-top: 2px solid var(--line); padding-top: 0.7rem; }
.stat strong { display: block; font-family: var(--serif); font-size: 1.8rem; line-height: 1; }
.stat span { color: var(--muted); font-size: 0.86rem; }
.progress-line { height: 5px; border-radius: 999px; background: #e3ded2; overflow: hidden; }
.progress-line > span { display: block; height: 100%; border-radius: inherit; background: var(--indigo); }
.progress-meta { display: flex; justify-content: space-between; color: var(--muted); font-size: 0.88rem; }
.today-kanji { text-align: center; display: flex; flex-direction: column; justify-content: center; }
.today-kanji .glyph { font-family: var(--serif); font-size: clamp(6rem, 16vw, 9rem); line-height: 1; color: var(--indigo); }
.today-kanji .reading { font-family: var(--serif); font-size: 1.25rem; }
.audio-actions { display: flex; justify-content: center; flex-wrap: wrap; gap: 0.5rem; margin-top: 1rem; }

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.45rem;
  border: 1px solid var(--indigo);
  border-radius: 999px;
  background: var(--indigo);
  color: #fff;
  padding: 0.62rem 1rem;
  font-weight: 700;
  text-decoration: none;
}
.btn:hover { background: var(--indigo-dark); }
.btn.secondary { background: transparent; color: var(--indigo); }
.btn.secondary:hover { background: rgba(61, 90, 128, 0.08); }
.btn.sage { border-color: var(--sage); background: var(--sage); }
.btn.ghost { border-color: var(--line); background: var(--white); color: var(--ink); }
.btn:disabled { cursor: not-allowed; opacity: 0.48; }
.btn.small-btn { padding: 0.42rem 0.75rem; font-size: 0.9rem; }

.grid { display: grid; gap: 1rem; }
.grid.two { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid.three { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid.four { grid-template-columns: repeat(4, minmax(0, 1fr)); }
.weekly-grid { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 1rem; }
.weekly-cell { border-left: 3px solid var(--sage); padding-left: 0.8rem; }
.weekly-cell strong { display: block; font-family: var(--serif); font-size: 2rem; line-height: 1.1; }
.quick-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 1rem; }
.quick-card { text-align: left; }
.quick-card .icon { width: 1.6rem; height: 1.6rem; color: var(--indigo); }
.quick-card h3 { margin-bottom: 0.3rem; }
.quick-card p { margin: 0; color: var(--muted); }

.badge-grid { display: flex; flex-wrap: wrap; gap: 0.9rem; }
.badge-seal {
  width: 7.3rem;
  min-height: 7.3rem;
  border: 1.5px solid var(--line);
  border-radius: 50%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 0.7rem;
  color: #aaa294;
  background: rgba(255,255,255,0.45);
  box-shadow: inset 0 0 0 5px var(--paper), inset 0 0 0 7px var(--line);
}
.badge-seal.earned { color: var(--indigo); border-color: var(--indigo); box-shadow: inset 0 0 0 5px var(--paper), inset 0 0 0 7px var(--indigo); }
.badge-seal strong { font-family: var(--serif); font-size: 0.95rem; line-height: 1.25; }
.badge-seal span { font-size: 0.68rem; line-height: 1.35; margin-top: 0.25rem; }

.tabs, .segmented { display: inline-flex; flex-wrap: wrap; gap: 0.35rem; padding: 0.3rem; border: 1px solid var(--line); border-radius: 999px; background: rgba(255,255,255,0.72); }
.tabs button, .segmented button { border: 0; border-radius: 999px; background: transparent; color: var(--muted); padding: 0.5rem 0.9rem; font-weight: 700; }
.tabs button.active, .segmented button.active { background: var(--indigo); color: white; }
.kana-grid { display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); gap: 0.65rem; margin-top: 1rem; }
.kana-cell {
  min-height: 6.2rem;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--white);
  color: var(--ink);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.15rem;
}
.kana-cell:hover { border-color: var(--indigo); transform: translateY(-1px); }
.kana-cell .glyph { font-family: var(--serif); font-size: 2.2rem; line-height: 1; }
.kana-cell .romaji { color: var(--muted); font-size: 0.86rem; letter-spacing: 0.08em; }
.kana-cell.empty { visibility: hidden; }
.focus-card { text-align: center; padding: clamp(1.4rem, 5vw, 3rem); }
.focus-glyph { font-family: var(--serif); font-size: clamp(7rem, 28vw, 14rem); line-height: 0.95; color: var(--indigo); }
.focus-prompt { color: var(--muted); letter-spacing: 0.08em; }
.option-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 0.8rem; margin-top: 1.2rem; }
.option-btn {
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--white);
  padding: 1rem;
  font-weight: 700;
}
.option-btn:hover { border-color: var(--indigo); }
.option-btn.correct { border-color: var(--sage); background: var(--sage-soft); }
.option-btn.wrong { border-color: var(--danger); background: #f7e9e6; }
.feedback { min-height: 1.8rem; margin-top: 1rem; font-weight: 700; }
.feedback.good { color: var(--sage); }
.feedback.bad { color: var(--danger); }

.level-heading { display: flex; align-items: baseline; gap: 1rem; margin: 2.2rem 0 1rem; border-bottom: 1px solid var(--line); padding-bottom: 0.6rem; }
.level-heading h2 { margin: 0; font-family: var(--serif); font-size: 2rem; }
.level-heading span { color: var(--muted); }
.lesson-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 1rem; }
.lesson-card { display: flex; flex-direction: column; gap: 0.8rem; }
.lesson-card header { display: flex; justify-content: space-between; gap: 1rem; }
.lesson-no { color: var(--mustard); font-weight: 900; letter-spacing: 0.15em; }
.lesson-card h3 { margin: 0; font-family: var(--serif); font-size: 1.45rem; }
.lesson-card .jp-title { color: var(--muted); font-family: var(--serif); }
.lesson-meta { display: flex; flex-wrap: wrap; gap: 0.45rem; }
.pill { display: inline-flex; align-items: center; border: 1px solid var(--line); border-radius: 999px; padding: 0.18rem 0.55rem; color: var(--muted); font-size: 0.82rem; background: rgba(255,255,255,0.65); }
.pill.done { border-color: var(--sage); color: var(--sage); background: var(--sage-soft); }
.lesson-card .btn { align-self: flex-start; margin-top: auto; }

.vocab-grid { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 0.8rem; }
.flip-card { min-height: 11.5rem; border: 0; background: transparent; perspective: 1000px; padding: 0; text-align: inherit; }
.flip-inner { position: relative; width: 100%; height: 100%; min-height: 11.5rem; transition: transform 0.55s; transform-style: preserve-3d; }
.flip-card.flipped .flip-inner { transform: rotateY(180deg); }
.flip-face {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.45rem;
  border: 1px solid var(--line);
  border-radius: 13px;
  background: var(--white);
  padding: 1rem;
  backface-visibility: hidden;
  box-shadow: var(--shadow);
}
.flip-face.back { transform: rotateY(180deg); background: var(--indigo); color: white; border-color: var(--indigo); }
.flip-face .word { font-family: var(--serif); font-size: 2rem; line-height: 1.2; text-align: center; }
.flip-face ruby { ruby-position: over; }
.flip-face rt { color: var(--muted); font-family: var(--sans); font-size: 0.72rem; letter-spacing: 0.04em; }
.flip-face.back rt { color: rgba(255,255,255,0.75); }
.flip-face .meaning { font-size: 1.15rem; font-weight: 800; text-align: center; }
.flip-face .tap { color: var(--muted); font-size: 0.78rem; }
.flip-face.back .tap { color: rgba(255,255,255,0.78); }

.sentence-list { display: grid; gap: 0.9rem; }
.sentence-card { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 1rem; align-items: center; }
.sentence-card .jp { font-family: var(--serif); font-size: clamp(1.35rem, 3vw, 1.9rem); line-height: 1.45; }
.sentence-card .kana { color: var(--indigo); margin-top: 0.15rem; }
.sentence-card .zh { color: var(--muted); border-top: 1px solid var(--line); margin-top: 0.7rem; padding-top: 0.7rem; }
.sentence-actions { display: flex; flex-direction: column; gap: 0.45rem; }
.grammar-box { border-left: 4px solid var(--mustard); background: #fffaf0; }
.exercise { margin-top: 1rem; }
.exercise h3 { display: flex; align-items: center; gap: 0.5rem; }
.match-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; }
.match-column { display: grid; gap: 0.55rem; }
.match-btn { border: 1px solid var(--line); background: var(--white); border-radius: 10px; padding: 0.8rem; font-weight: 700; }
.match-btn.selected { border-color: var(--mustard); box-shadow: 0 0 0 2px rgba(217,164,65,0.25); }
.match-btn.matched { border-color: var(--sage); background: var(--sage-soft); color: var(--sage); }
.result-banner { border: 1px solid var(--sage); background: var(--sage-soft); border-radius: 12px; padding: 1rem; margin-top: 1rem; }

.kanji-focus { text-align: center; }
.kanji-focus .focus-glyph { font-size: clamp(8rem, 30vw, 15rem); }
.kanji-nav { display: flex; justify-content: center; align-items: center; gap: 1rem; margin-top: 1rem; }
.stroke-box { margin: 1rem auto 0; max-width: 650px; text-align: left; border: 1px dashed #bfb6a3; border-radius: 10px; padding: 0.9rem 1rem; background: rgba(255,255,255,0.6); }
.kanji-strip { display: flex; gap: 0.45rem; overflow-x: auto; padding: 0.8rem 0.1rem; }
.kanji-chip { flex: 0 0 auto; width: 3.2rem; height: 3.2rem; border: 1px solid var(--line); border-radius: 50%; background: var(--white); font-family: var(--serif); font-size: 1.25rem; }
.kanji-chip.active { background: var(--indigo); color: white; border-color: var(--indigo); }

.review-word { font-family: var(--serif); font-size: clamp(3rem, 10vw, 6rem); line-height: 1.15; }
.review-answer { border-top: 1px solid var(--line); margin-top: 1.2rem; padding-top: 1.2rem; }
.rating-grid { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 0.7rem; margin-top: 1rem; }
.rating-grid button { border: 1px solid var(--line); border-radius: 11px; background: white; padding: 0.85rem 0.5rem; font-weight: 800; }
.rating-grid button small { display: block; color: var(--muted); font-weight: 500; }
.speaking-sentence { text-align: center; }
.speaking-sentence .jp { font-family: var(--serif); font-size: clamp(2rem, 6vw, 3.6rem); line-height: 1.35; }
.recorder-panel { display: flex; flex-wrap: wrap; justify-content: center; gap: 0.7rem; margin-top: 1.2rem; }
.score { font-family: var(--serif); font-size: 3rem; color: var(--indigo); }
.transcript { border: 1px solid var(--line); background: white; border-radius: 10px; padding: 0.8rem; margin-top: 1rem; }
.empty-state { text-align: center; padding: 2rem 1rem; color: var(--muted); }
.toast {
  position: fixed;
  left: 50%;
  bottom: 1.2rem;
  z-index: 50;
  transform: translate(-50%, 150%);
  max-width: min(92vw, 520px);
  border-radius: 999px;
  background: var(--ink);
  color: white;
  padding: 0.75rem 1.1rem;
  box-shadow: 0 14px 35px rgba(0,0,0,0.22);
  transition: transform 0.25s ease;
  text-align: center;
}
.toast.show { transform: translate(-50%, 0); }
.site-footer { border-top: 1px solid var(--line); color: var(--muted); padding: 1.4rem clamp(1rem, 4vw, 3rem); display: flex; justify-content: space-between; gap: 1rem; flex-wrap: wrap; }
.site-footer p { margin: 0; }
.noscript { padding: 1rem; text-align: center; }

@media (max-width: 860px) {
  .site-header { align-items: flex-start; flex-direction: column; gap: 0.35rem; }
  .main-nav { width: 100%; }
  .hero, .grid.two, .lesson-grid { grid-template-columns: 1fr; }
  .grid.three, .grid.four, .quick-grid { grid-template-columns: 1fr; }
  .weekly-grid { grid-template-columns: repeat(2, 1fr); }
  .vocab-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .sentence-card { grid-template-columns: 1fr; }
  .sentence-actions { flex-direction: row; }
  .rating-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 520px) {
  .app-shell { width: min(100% - 1rem, 1180px); padding-top: 1rem; }
  .hero-stats { grid-template-columns: 1fr 1fr 1fr; gap: 0.45rem; }
  .stat strong { font-size: 1.35rem; }
  .kana-grid { grid-template-columns: repeat(5, minmax(0, 1fr)); gap: 0.35rem; }
  .kana-cell { min-height: 4.7rem; border-radius: 9px; }
  .kana-cell .glyph { font-size: 1.55rem; }
  .option-grid { grid-template-columns: 1fr; }
  .vocab-grid { grid-template-columns: 1fr 1fr; }
  .flip-card, .flip-inner { min-height: 10rem; }
  .flip-face .word { font-size: 1.55rem; }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: 0.01ms !important; animation-duration: 0.01ms !important; }
}