/* ─── Flashcards · Q&A ─── */
.qna {
  display: flex;
  flex-direction: column;
  gap: 22px;
}

.qna__head {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 32px;
  align-items: end;
}
@media (max-width: 820px) {
  .qna__head { grid-template-columns: 1fr; }
}
.qna__kicker {
  font-family: var(--ff-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--vermillion);
  margin-bottom: 8px;
  text-transform: uppercase;
}
.qna__title {
  font-family: var(--ff-serif);
  font-weight: 500;
  font-size: 32px;
  line-height: 1.15;
  margin: 0 0 12px;
  color: var(--ink);
}
.qna__lede {
  font-family: var(--ff-sans);
  font-size: 14px;
  line-height: 1.55;
  color: var(--ink-soft);
  max-width: 66ch;
  margin: 0;
}
.qna__lede b { font-family: var(--ff-mono); font-size: 11px; background: var(--ink); color: var(--paper); padding: 2px 5px; letter-spacing: 0.08em; }

.qna__stats {
  display: flex;
  gap: 22px;
  font-family: var(--ff-serif);
}
.qna__stats div {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  border-left: 1px solid var(--paper-edge);
  padding-left: 22px;
}
.qna__stats b {
  font-size: 32px;
  font-weight: 500;
  line-height: 1;
  color: var(--ink);
}
.qna__stats span {
  font-family: var(--ff-mono);
  font-size: 10px;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin-top: 4px;
}

/* ─── Module tabs ─── */
.qna__modules {
  display: grid;
  grid-template-columns: repeat(9, minmax(0, 1fr));
  gap: 6px;
  background: var(--paper-edge);
  border: 1px solid var(--paper-edge);
  padding: 1px;
}
@media (max-width: 1180px) {
  .qna__modules { grid-template-columns: repeat(5, 1fr); }
}
@media (max-width: 760px) {
  .qna__modules { grid-template-columns: repeat(3, 1fr); }
}
.qna__modules button {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 3px;
  padding: 12px 12px;
  background: rgba(255,255,255,0.7);
  border: 0;
  cursor: pointer;
  font: inherit;
  color: inherit;
  text-align: left;
  transition: background 0.15s;
  min-height: 72px;
}
.qna__modules button:hover { background: #fff; }
.qna__modules button.on {
  background: var(--ink);
  color: var(--paper);
}
.qna__modules button .label {
  font-family: var(--ff-serif);
  font-size: 15px;
  font-weight: 500;
  line-height: 1.1;
  white-space: nowrap;
}
.qna__modules button .rank {
  font-family: var(--ff-mono);
  font-size: 9px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-mute);
  line-height: 1.3;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 100%;
}
.qna__modules button.on .rank { color: var(--paper-edge); }
.qna__modules button .prog {
  font-family: var(--ff-mono);
  font-size: 10px;
  color: var(--vermillion);
  margin-top: auto;
  letter-spacing: 0.05em;
}
.qna__modules button.on .prog { color: var(--paper); }

/* ─── Toolbar ─── */
.qna__toolbar {
  display: flex;
  gap: 14px;
  align-items: center;
  flex-wrap: wrap;
}
.qna__toolbar .seg {
  display: flex;
  border: 1px solid var(--paper-edge);
  background: rgba(255,255,255,0.3);
}
.qna__toolbar .seg button {
  padding: 8px 16px;
  background: transparent;
  border: 0;
  font-family: var(--ff-sans);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--ink-soft);
  cursor: pointer;
  border-right: 1px solid var(--paper-edge);
}
.qna__toolbar .seg button:last-child { border-right: 0; }
.qna__toolbar .seg button.on { background: var(--ink); color: var(--paper); }

.qna__ghost {
  padding: 8px 14px;
  background: transparent;
  border: 1px solid var(--paper-edge);
  font-family: var(--ff-sans);
  font-size: 12px;
  color: var(--ink-soft);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}
.qna__ghost:hover { background: rgba(255,255,255,0.5); color: var(--ink); }

.qna__counter {
  margin-left: auto;
  font-family: var(--ff-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--ink-mute);
}
.qna__counter b {
  font-family: var(--ff-serif);
  font-size: 18px;
  font-weight: 500;
  color: var(--ink);
}
.qna__counter .sep { margin: 0 8px; color: var(--paper-edge); }

/* ─── Progress bar ─── */
.qna__bar {
  height: 2px;
  background: var(--paper-edge);
  position: relative;
  overflow: hidden;
}
.qna__bar-fill {
  position: absolute;
  inset: 0 auto 0 0;
  background: var(--vermillion);
  transition: width 0.25s ease;
}

/* ─── Stage ─── */
.qna__stage {
  display: grid;
  grid-template-columns: 48px 1fr 48px;
  gap: 16px;
  align-items: stretch;
  min-height: 460px;
}
@media (max-width: 600px) {
  .qna__stage { grid-template-columns: 36px 1fr 36px; min-height: 420px; }
}

.qna__nav-btn {
  background: transparent;
  border: 1px solid var(--paper-edge);
  color: var(--ink-mute);
  display: grid;
  place-items: center;
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
}
.qna__nav-btn:hover {
  background: var(--ink);
  color: var(--paper);
  border-color: var(--ink);
}
.qna__nav-btn svg { width: 18px; height: 18px; }

/* ─── Flip card ─── */
.flip {
  perspective: 1800px;
  cursor: pointer;
  outline: none;
}
.flip:focus-visible .flip__inner {
  box-shadow: 0 0 0 2px var(--vermillion), 0 30px 60px -30px rgba(0,0,0,0.35);
}
.flip__inner {
  position: relative;
  width: 100%;
  height: 100%;
  min-height: 460px;
  transition: transform 0.6s cubic-bezier(0.22, 1, 0.36, 1);
  transform-style: preserve-3d;
  box-shadow: 0 1px 0 rgba(0,0,0,0.04), 0 30px 60px -36px rgba(0,0,0,0.25);
}
.flip.is-flipped .flip__inner { transform: rotateY(180deg); }

.flip__face {
  position: absolute;
  inset: 0;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  transform: translateZ(0);
  padding: 36px 44px;
  display: flex;
  flex-direction: column;
  border: 1px solid var(--paper-edge);
  background: #fff;
  background-image:
    radial-gradient(1000px 700px at 12% 0%, rgba(255,255,255,0.9) 0%, transparent 50%),
    radial-gradient(900px 700px at 90% 100%, rgba(214,200,168,0.35) 0%, transparent 60%),
    linear-gradient(180deg, #fcf7eb, #f2ead6);
  overflow: hidden;
}
.flip__back {
  transform: rotateY(180deg) translateZ(0);
  background:
    radial-gradient(900px 700px at 90% 0%, rgba(178,53,28,0.06) 0%, transparent 50%),
    linear-gradient(180deg, #f7efde, #ebe1c8);
}
body.theme-ink .flip__face {
  background: linear-gradient(180deg, #231d16, #1a1511);
  border-color: var(--paper-edge);
}
body.theme-ink .flip__back {
  background: linear-gradient(180deg, #2a2119, #1c1612);
}

/* big ghost kanji on face */
.flip__qmark, .flip__amark {
  position: absolute;
  top: 40%;
  right: 40px;
  transform: translateY(-50%);
  font-family: var(--ff-kanji);
  font-size: 320px;
  line-height: 1;
  color: var(--paper-edge);
  opacity: 0.55;
  pointer-events: none;
  user-select: none;
  font-weight: 400;
  z-index: 0;
}
.flip__amark { color: rgba(178, 53, 28, 0.12); }
body.theme-ink .flip__qmark { color: rgba(166, 124, 42, 0.16); }
body.theme-ink .flip__amark { color: rgba(217, 83, 51, 0.14); }
@media (max-width: 600px) {
  .flip__qmark, .flip__amark { font-size: 220px; right: 20px; }
}

.flip__meta {
  position: relative;
  z-index: 1;
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 18px;
}
.flip__module {
  font-family: var(--ff-mono);
  font-size: 10px;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--vermillion);
}
.flip__idx {
  font-family: var(--ff-kanji);
  font-size: 16px;
  letter-spacing: 0.2em;
  color: var(--ink-mute);
}

.flip__q {
  position: relative;
  z-index: 1;
  margin: 24px 0 0;
  font-family: var(--ff-serif);
  font-weight: 500;
  font-size: 34px;
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--ink);
  max-width: 22ch;
  text-wrap: pretty;
}
@media (max-width: 600px) {
  .flip__q { font-size: 24px; }
}

.flip__tags {
  position: relative;
  z-index: 1;
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  margin-top: 20px;
}
.flip__tag {
  font-family: var(--ff-mono);
  font-size: 10px;
  letter-spacing: 0.08em;
  color: var(--ink-mute);
  padding: 3px 8px;
  border: 1px solid var(--paper-edge);
  background: rgba(255,255,255,0.5);
}

.flip__hint {
  position: relative;
  z-index: 1;
  margin-top: auto;
  font-family: var(--ff-mono);
  font-size: 10px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ink-faint);
  padding-top: 20px;
  border-top: 1px dashed var(--paper-edge);
}

.flip__q-small {
  position: relative;
  z-index: 1;
  font-family: var(--ff-serif);
  font-style: italic;
  font-size: 15px;
  line-height: 1.4;
  color: var(--ink-mute);
  margin-bottom: 18px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--paper-edge);
  max-width: 60ch;
}

.flip__a {
  position: relative;
  z-index: 1;
  margin: 0;
  font-family: var(--ff-serif);
  font-size: 18px;
  line-height: 1.55;
  color: var(--ink);
  max-width: 58ch;
  text-wrap: pretty;
  overflow-y: auto;
  flex: 1;
}
@media (max-width: 600px) {
  .flip__a { font-size: 15px; }
}

/* known tint */
.flip.is-known .flip__face {
  border-color: var(--gold);
  box-shadow: inset 0 0 0 1px rgba(166, 124, 42, 0.35);
}
.flip.is-known .flip__face::before {
  content: "✓ 覚";
  position: absolute;
  top: 24px;
  left: -6px;
  background: var(--gold);
  color: var(--paper);
  font-family: var(--ff-kanji);
  font-size: 12px;
  letter-spacing: 0.1em;
  padding: 4px 12px 4px 14px;
  z-index: 2;
  box-shadow: 2px 2px 0 rgba(0,0,0,0.08);
}

/* ─── Actions ─── */
.qna__actions {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  align-items: center;
}
.qna__mark {
  padding: 10px 16px;
  background: transparent;
  border: 1px solid var(--paper-edge);
  font-family: var(--ff-sans);
  font-size: 16px;
  color: var(--ink-soft);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 10px;
  transition: background-color 0.15s, border-color 0.15s, color 0.15s;
}
.qna__mark .tick {
  font-family: var(--ff-mono);
  font-size: 14px;
  color: var(--ink-mute);
}
.qna__mark:hover { background: rgba(255,255,255,0.5); }
.qna__mark.on {
  background: var(--gold);
  color: var(--paper);
  border-color: var(--gold);
}
.qna__mark.on .tick { color: var(--paper); }

.qna__actions .kbd, .qna__mark .kbd {
  font-family: var(--ff-mono);
  font-size: 9px;
  letter-spacing: 0.1em;
  padding: 2px 6px;
  border: 1px solid currentColor;
  opacity: 0.5;
  margin-left: 4px;
}

/* ─── Dot nav ─── */
.qna__dots {
  display: flex;
  gap: 4px;
  flex-wrap: wrap;
  padding-top: 16px;
  border-top: 1px solid var(--paper-edge);
}
.qna__dots .dot {
  width: 14px;
  height: 14px;
  border: 1px solid var(--paper-edge);
  background: transparent;
  cursor: pointer;
  padding: 0;
  transition: background-color 0.15s, border-color 0.15s, transform 0.15s;
}
.qna__dots .dot:hover { background: var(--ink-faint); }
.qna__dots .dot.known { background: var(--gold); border-color: var(--gold); }
.qna__dots .dot.on {
  background: var(--vermillion);
  border-color: var(--vermillion);
  transform: scale(1.15);
}