@import url('https://fonts.googleapis.com/css2?family=Outfit:wght@400;500;600;700&display=swap');

/* ── TOKENS ───────────────────────────────────────── */
:root {
  --es-primary:   #0d9488;
  --es-dark:      #0f766e;
  --es-soft:      #f0fdfa;
  --es-mid:       #5eead4;
  --es-ok:        #16a34a;
  --es-ok-soft:   #dcfce7;
  --es-warn:      #d97706;
  --es-warn-soft: #fef3c7;
  --es-info:      #2563eb;
  --es-info-soft: #eff6ff;
  --es-surface:   #fff;
  --es-bg:        #f8fffe;
  --es-border:    #ccede9;
  --es-text:      #134e4a;
  --es-muted:     #4a8c88;
  --es-r:         14px;
  --es-shadow:    0 2px 12px rgba(0,0,0,0.07);
  --es-shadow-lg: 0 6px 24px rgba(0,0,0,0.11);
  --ex-neutral-border: var(--es-border);
  --ex-state-answered: var(--es-info);
  --ex-state-answered-soft: var(--es-info-soft);
  --ex-state-correct: var(--es-ok);
  --ex-state-correct-soft: var(--es-ok-soft);
  --ex-state-incorrect: #dc2626;
  --ex-state-incorrect-soft: #fef2f2;
}

/* ── BASE ─────────────────────────────────────────── */
main { padding-top: 60px; }

/* ── HEADER ───────────────────────────────────────── */
.lesson-header {
  background: linear-gradient(135deg, var(--es-dark) 0%, var(--es-primary) 60%, #14b8a6 100%);
  color: #fff;
  padding: 2.5rem 1rem 2rem;
  text-align: center;
  margin-bottom: 1.25rem;
}
.lesson-header h1 {
  font-family: 'Outfit', sans-serif;
  font-size: clamp(1.55rem, 6vw, 2.5rem);
  font-weight: 700;
  margin-bottom: 0.45rem;
  line-height: 1.15;
}
.lesson-header p { opacity: 0.88; font-size: 0.97rem; }
.lesson-header .lang-badge {
  display: inline-block;
  background: rgba(255,255,255,0.18);
  border: 1px solid rgba(255,255,255,0.35);
  border-radius: 999px;
  padding: 0.25rem 1rem;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  margin-bottom: 0.85rem;
}

/* ── CONTAINER ────────────────────────────────────── */
.lesson-container {
  width: min(100%, 900px);
  margin: 0 auto;
  padding: 0 0.9rem 3.5rem;
}

/* ── PROGRESS ─────────────────────────────────────── */
.progress-bar-wrap {
  background: var(--es-surface);
  border-radius: var(--es-r);
  padding: 1rem 1.15rem;
  margin-bottom: 1.25rem;
  box-shadow: var(--es-shadow);
  border: 1px solid var(--es-border);
}
.progress-label {
  font-size: 0.88rem;
  color: var(--es-muted);
  margin-bottom: 0.55rem;
  font-weight: 500;
}
.progress-track {
  height: 10px;
  background: var(--es-border);
  border-radius: 999px;
  overflow: hidden;
}
.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--es-primary), #14b8a6 50%, var(--es-ok));
  border-radius: 999px;
  width: 0%;
  transition: width 0.4s cubic-bezier(.4,0,.2,1);
}
.progress-fill.all-done { animation: pop 0.5s ease; }

/* ── EXERCISE CARD ────────────────────────────────── */
.ex-card {
  background: var(--es-surface);
  border-radius: var(--es-r);
  padding: 1.15rem;
  margin-bottom: 1.15rem;
  box-shadow: var(--es-shadow);
  border: 1px solid var(--es-border);
  border-left: 4px solid var(--es-primary);
  transition: box-shadow 0.2s;
}
.ex-card:focus-within { box-shadow: var(--es-shadow-lg); }
.ex-card h2 {
  font-family: 'Outfit', sans-serif;
  color: var(--es-dark);
  font-size: 1.08rem;
  margin-bottom: 0.3rem;
  line-height: 1.3;
}
.ex-instructions {
  color: var(--es-muted);
  margin-bottom: 1rem;
  font-size: 0.92rem;
  line-height: 1.6;
}

/* ── Q ITEMS ──────────────────────────────────────── */
.q-list { display: grid; gap: 0.7rem; }
.q-item {
  background: var(--es-surface);
  border-radius: 10px;
  padding: 0.85rem 1rem;
  border: 2px solid var(--ex-neutral-border);
  line-height: 1.85;
  transition: border-color 0.25s, background 0.25s, opacity 0.3s;
}
.q-item.item-answered { border-color: var(--ex-state-answered); background: var(--ex-state-answered-soft); }
.q-item.item-correct { border-color: var(--ex-state-correct); background: var(--ex-state-correct-soft); }
.q-item.item-incorrect { border-color: var(--ex-state-incorrect); background: var(--ex-state-incorrect-soft); }

/* ── FILL INPUTS ──────────────────────────────────── */
.inline-input {
  display: inline-block;
  width: min(100%, 185px);
  padding: 0.2rem 0.4rem;
  border: none;
  border-bottom: 2px solid var(--es-primary);
  background: transparent;
  font-family: 'Inter', sans-serif;
  font-size: 0.94rem;
  color: var(--es-text);
  outline: none;
  vertical-align: middle;
  margin: 0 2px;
  transition: border-color 0.2s;
}
.wide-input { width: min(100%, 280px); }
.inline-input.correct {
  border-color: var(--ex-state-correct);
  background: var(--ex-state-correct-soft);
  border-radius: 4px 4px 0 0;
}
.inline-input.incorrect {
  border-color: var(--ex-state-incorrect);
  background: var(--ex-state-incorrect-soft);
  border-radius: 4px 4px 0 0;
  animation: incorrectPulse 0.42s ease;
}
.answer-tip {
  display: block;
  color: var(--es-muted);
  font-size: 0.8rem;
  font-weight: 600;
  line-height: 1.35;
  margin-top: 0.25rem;
}
.answer-tip:empty { display: none; }

/* ── SCORE ────────────────────────────────────────── */
.ex-score {
  margin-top: 0.85rem;
  font-size: 0.87rem;
  font-weight: 600;
  color: var(--es-muted);
  min-height: 1.2em;
}
.ex-score.has-results { color: var(--es-dark); }

/* ── CHOICE ───────────────────────────────────────── */
.choice-grid { display: grid; gap: 0.5rem; margin-top: 0.5rem; }
.choice-btn {
  width: 100%;
  border: 2px solid var(--es-border);
  border-radius: 10px;
  background: var(--es-surface);
  color: var(--es-text);
  padding: 0.7rem 0.9rem;
  font: inherit;
  font-size: 0.9rem;
  text-align: left;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.65rem;
  transition: border-color 0.18s, background 0.18s, transform 0.12s;
}
.choice-btn::before {
  content: '';
  width: 14px;
  min-width: 14px;
  height: 14px;
  border-radius: 50%;
  border: 2px solid var(--es-border);
  transition: border-color 0.18s, background 0.18s;
}
.choice-btn:hover, .choice-btn:focus {
  border-color: var(--es-primary);
  outline: none;
  transform: translateY(-1px);
}
.choice-btn:hover::before { border-color: var(--es-primary); }
.choice-btn.correct { border-color: var(--ex-state-correct); background: var(--ex-state-correct-soft); }
.choice-btn.correct::before { border-color: var(--ex-state-correct); background: var(--ex-state-correct); }
.choice-btn.incorrect { border-color: var(--ex-state-incorrect); background: var(--ex-state-incorrect-soft); animation: incorrectPulse 0.42s ease; }
.choice-btn.incorrect::before { border-color: var(--ex-state-incorrect); background: var(--ex-state-incorrect); }

/* ── DRAG CHIP BANK ───────────────────────────────── */
.chip-bank {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  padding: 0.75rem;
  background: var(--es-bg);
  border-radius: 10px;
  border: 1px solid var(--es-border);
  min-height: 52px;
  align-items: flex-start;
}

/* ── DRAG CHIPS ───────────────────────────────────── */
.drag-chip {
  border: 1px solid var(--es-mid);
  background: var(--es-soft);
  color: var(--es-dark);
  border-radius: 999px;
  padding: 0.4rem 0.85rem;
  font: inherit;
  font-size: 0.87rem;
  font-weight: 600;
  cursor: grab;
  touch-action: none;
  user-select: none;
  transition: transform 0.12s, box-shadow 0.12s, opacity 0.2s;
}
.drag-chip:hover { transform: translateY(-2px); box-shadow: 0 3px 8px rgba(220,38,38,0.2); }
.drag-chip:active { cursor: grabbing; }
.drag-chip.selected { outline: 3px solid var(--es-mid); transform: scale(1.05); }
.drag-chip.used { opacity: 0.32; cursor: default; transform: none; box-shadow: none; }

/* ── CLASSIFY ─────────────────────────────────────── */
.match-layout { display: grid; gap: 1rem; }
.classify-layout { display: grid; gap: 1rem; }
.classify-buckets { display: grid; gap: 0.75rem; }
.classify-bucket {
  min-height: 96px;
  border: 2px dashed var(--es-border);
  background: var(--es-surface);
  border-radius: 12px;
  padding: 0.75rem;
  transition: border-color 0.2s, background 0.2s;
}
.classify-bucket.over { border-color: var(--es-primary); background: var(--es-soft); }
.bucket-heading {
  margin: 0 0 0.55rem;
  color: var(--es-text);
  font-family: 'Outfit', sans-serif;
  font-size: 0.93rem;
  font-weight: 600;
}
.bucket-items { display: flex; flex-wrap: wrap; gap: 0.4rem; min-height: 40px; align-items: flex-start; }
.bucket-items .drag-chip.correct { border-color: var(--ex-state-correct); background: var(--ex-state-correct-soft); color: #166534; }
.bucket-items .drag-chip.incorrect { border-color: var(--ex-state-incorrect); background: var(--ex-state-incorrect-soft); color: var(--ex-state-incorrect); animation: incorrectPulse 0.42s ease; }

/* ── MATCH / DROP ZONES ───────────────────────────── */
.drop-list { display: grid; gap: 0.65rem; }
.drop-row { display: grid; gap: 0.4rem; }
.drop-prompt { color: var(--es-text); font-size: 0.92rem; line-height: 1.5; }
.drop-zone {
  min-height: 48px;
  border: 2px dashed var(--es-border);
  background: var(--es-bg);
  border-radius: 10px;
  padding: 0.6rem 0.8rem;
  color: var(--es-muted);
  font-size: 0.88rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  cursor: pointer;
  transition: border-color 0.2s, background 0.2s;
}
.drop-zone::before { content: '→'; opacity: 0.4; flex-shrink: 0; font-style: normal; }
.drop-zone.over { border-color: var(--es-primary); background: var(--es-soft); }
.drop-zone.correct { border-style: solid; border-color: var(--ex-state-correct); background: var(--ex-state-correct-soft); color: #166534; }
.drop-zone.correct::before { content: '✓'; color: var(--ex-state-correct); opacity: 1; }
.drop-zone.incorrect { border-style: solid; border-color: var(--ex-state-incorrect); background: var(--ex-state-incorrect-soft); color: var(--ex-state-incorrect); animation: incorrectPulse 0.42s ease; }
.drop-zone.incorrect::before { content: '✗'; color: var(--ex-state-incorrect); opacity: 1; }

/* ── WRITING ──────────────────────────────────────── */
.answer-area {
  width: 100%;
  min-height: 100px;
  resize: vertical;
  border: 2px solid var(--es-border);
  border-radius: 10px;
  padding: 0.75rem 1rem;
  font: inherit;
  font-size: 0.9rem;
  color: var(--es-text);
  background: var(--es-surface);
  outline: none;
  transition: border-color 0.2s, box-shadow 0.2s;
}
.answer-area:focus {
  border-color: var(--es-primary);
  box-shadow: 0 0 0 3px rgba(220,38,38,0.1);
}
.prompt-list {
  padding-left: 1.25rem;
  margin: 0 0 0.75rem;
  color: var(--es-text);
  line-height: 1.75;
  font-size: 0.92rem;
}

/* ── NOTES / RULES ────────────────────────────────── */
.see-why-card { border-left-color: var(--es-warn); }
.rules-card { border-left-color: var(--es-info); }
.toggle-btn {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.75rem;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
  font-family: 'Outfit', sans-serif;
  font-size: 1rem;
  font-weight: 700;
  text-align: left;
}
.see-why-card .toggle-btn { color: var(--es-warn); }
.rules-card .toggle-btn { color: var(--es-info); }
.toggle-btn i { transition: transform 0.25s ease; flex-shrink: 0; }
.toggle-btn[aria-expanded="true"] i { transform: rotate(180deg); }
.collapsible-body { margin-top: 1.1rem; }
.collapsible-body.hidden { display: none; }
.note-section, .rule-section { margin-bottom: 1.25rem; }
.note-section:last-child, .rule-section:last-child { margin-bottom: 0; }
.note-heading, .rule-heading {
  font-family: 'Outfit', sans-serif;
  font-size: 0.95rem;
  font-weight: 700;
  margin-bottom: 0.45rem;
  padding-bottom: 0.3rem;
  border-bottom: 2px solid var(--es-border);
}
.note-heading { color: #92400e; border-bottom-color: #fcd34d; }
.rule-heading { color: #1e3a8a; }
.note-list { padding-left: 1.2rem; margin: 0; }
.note-list li { margin-bottom: 0.45rem; font-size: 0.88rem; color: var(--es-text); line-height: 1.6; }
.ref-table { width: 100%; border-collapse: collapse; font-size: 0.83rem; margin-top: 0.5rem; }
.ref-table th {
  background: var(--es-bg);
  color: #1e3a8a;
  font-family: 'Outfit', sans-serif;
  font-weight: 700;
  padding: 0.45rem 0.6rem;
  border: 1px solid var(--es-border);
  text-align: left;
}
.ref-table td { padding: 0.45rem 0.6rem; border: 1px solid var(--es-border); vertical-align: top; }
.ref-table td:first-child { font-weight: 700; color: var(--es-dark); }
.vocab-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 0.5rem;
  margin-top: 0.75rem;
}
.vocab-item {
  background: var(--es-bg);
  border-radius: 8px;
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--es-border);
  font-size: 0.82rem;
}
.vocab-item strong { color: var(--es-dark); font-family: 'Outfit', sans-serif; }
.vocab-item span { color: var(--es-muted); }

/* ── WORD BANK ────────────────────────────────────── */
.word-bank {
  display: flex;
  flex-wrap: wrap;
  gap: 0.2rem 0;
  padding: 0.65rem 1rem;
  background: var(--es-soft);
  border: 1px solid var(--es-border);
  border-radius: 10px;
  margin-bottom: 1rem;
  line-height: 1.9;
}
.wb-word {
  font-weight: 600;
  color: var(--es-dark);
  transition: opacity 0.2s;
}
.wb-sep { color: var(--es-muted); user-select: none; }
.wb-word.wb-used { text-decoration: line-through; opacity: 0.55; }

/* ── ANIMATIONS ───────────────────────────────────── */
@keyframes incorrectPulse {
  0%   { box-shadow: 0 0 0 0 rgba(220,38,38,0.34); }
  65%  { box-shadow: 0 0 0 6px rgba(220,38,38,0); }
  100% { box-shadow: none; }
}
@keyframes pop {
  0%   { transform: scaleX(1); }
  50%  { transform: scaleX(1.015); }
  100% { transform: scaleX(1); }
}

/* ── TABLET ───────────────────────────────────────── */
@media (min-width: 600px) {
  .lesson-container { padding: 0 1.5rem 4rem; }
  .ex-card { padding: 1.6rem; margin-bottom: 1.4rem; }
  .choice-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .drop-row { grid-template-columns: minmax(0, 1fr) minmax(175px, 0.52fr); align-items: center; }
}

/* ── DESKTOP ──────────────────────────────────────── */
@media (min-width: 768px) {
  main { padding-top: 72px; }
  .lesson-header { padding: 3rem 1.5rem 2.25rem; }
  .match-layout { grid-template-columns: minmax(210px, 0.8fr) minmax(0, 1.2fr); align-items: start; }
  .classify-buckets { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .choice-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
}

/* ── SMALL MOBILE ─────────────────────────────────── */
@media (max-width: 420px) {
  .q-item { font-size: 0.9rem; padding: 0.8rem 0.75rem; }
  .inline-input { width: 125px; font-size: 0.88rem; }
  .wide-input { width: 100%; display: block; margin: 0.4rem 0; }
  .ref-table { display: block; overflow-x: auto; }
  .vocab-grid { grid-template-columns: 1fr 1fr; }
  .choice-btn { font-size: 0.88rem; padding: 0.65rem 0.75rem; }
}