/* Study-режими: кнопки в папці, оверлей, флешкартки, тест. */

/* ---------- study bar (folder view) ---------- */

.study-bar { display: flex; gap: 12px; margin: 24px 0 4px; }

.study-btn {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 14px 18px;
  border: 1px solid var(--rule);
  border-radius: 12px;
  background: var(--paper-raised);
  text-align: left;
  cursor: pointer;
  box-shadow: 0 1px 3px rgba(31, 27, 22, .05);
  transition: border-color .15s, transform .1s;
}

.study-btn:hover:not(:disabled) { border-color: var(--vermilion); transform: translateY(-1px); }

.study-btn:disabled { opacity: .45; cursor: not-allowed; }

.study-btn-title { font: 600 16px var(--font-word); color: var(--ink); }

.study-btn-sub { font-size: 12px; color: var(--ink-faint); letter-spacing: .02em; }

/* ---------- study overlay (flashcards + quiz) ---------- */

#study-overlay {
  position: fixed;
  inset: 0;
  z-index: 30;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  background:
    url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='140' height='140'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2'/%3E%3C/filter%3E%3Crect width='140' height='140' filter='url(%23n)' opacity='0.035'/%3E%3C/svg%3E"),
    rgba(247, 243, 236, .97);
}

:root[data-theme="dark"] #study-overlay { background: rgba(16,13,9,.97); }

#study-overlay[hidden] { display: none; }

.study-panel {
  width: min(540px, 100%);
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.study-head {
  display: flex;
  align-items: center;
  gap: 14px;
}

.study-mode {
  font: 600 13px var(--font-ui);
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--vermilion);
}

.study-progress {
  font-size: 13px;
  color: var(--ink-soft);
  font-variant-numeric: tabular-nums;
}

.study-close {
  margin-left: auto;
  width: 34px;
  height: 34px;
  border: 1px solid var(--rule);
  border-radius: 50%;
  background: var(--paper-raised);
  font-size: 20px;
  line-height: 1;
  color: var(--ink-soft);
  cursor: pointer;
  transition: color .15s, border-color .15s;
}

.study-close:hover { color: var(--vermilion); border-color: var(--vermilion); }

.study-body { animation: rise .3s ease both; }

/* flashcard */

.flashcard {
  min-height: 320px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 18px;
  padding: 40px 32px;
  border: 1px solid var(--rule);
  border-radius: 18px;
  background: var(--paper-raised);
  box-shadow: 0 14px 44px rgba(31, 27, 22, .09);
  text-align: center;
  cursor: pointer;
}

.flashcard.revealed { cursor: default; }

.flashcard-word { font: 600 40px var(--font-word); color: var(--ink); }

.flashcard-hint { font: italic 400 14px var(--font-text); color: var(--ink-faint); }

.flashcard-divider { width: 40px; height: 1px; background: var(--rule); }

.flashcard-def { font: 400 19px/1.5 var(--font-text); color: var(--ink); max-width: 42ch; }

.flashcard-example {
  font: italic 400 16px/1.5 var(--font-text);
  color: var(--ink-soft);
  max-width: 42ch;
}

.flashcard-actions { display: flex; gap: 12px; }

.flashcard-actions[hidden] { display: none; }

.rate-btn {
  padding: 13px 26px;
  border-radius: 10px;
  border: 1px solid var(--rule);
  font: 600 15px var(--font-ui);
  cursor: pointer;
  transition: transform .1s, background .15s;
}

.rate-btn:active { transform: scale(.97); }

.rate-known { background: var(--success); border-color: var(--success); color: #fff; }

.rate-unknown { background: var(--paper-raised); color: var(--ink-soft); }

.rate-unknown:hover { border-color: var(--vermilion); color: var(--vermilion); }

/* quiz */

.quiz-word {
  font: 600 34px var(--font-word);
  color: var(--ink);
  text-align: center;
  margin-bottom: 6px;
}

.quiz-prompt {
  text-align: center;
  font: italic 400 14px var(--font-text);
  color: var(--ink-faint);
  margin-bottom: 20px;
}

.quiz-options { display: flex; flex-direction: column; gap: 12px; }

.quiz-option {
  padding: 15px 18px;
  border: 1px solid var(--rule);
  border-radius: 12px;
  background: var(--paper-raised);
  font: 400 15.5px/1.45 var(--font-text);
  color: var(--ink);
  text-align: left;
  cursor: pointer;
  transition: border-color .15s, background .15s;
}

.quiz-option:hover:not(:disabled) { border-color: var(--vermilion); }

.quiz-option:disabled { cursor: default; }

.quiz-option.correct {
  border-color: var(--success);
  background: var(--success-soft);
  color: var(--success);
}

.quiz-option.wrong {
  border-color: var(--vermilion);
  background: #f6e4df;
  color: var(--vermilion-dark);
}

:root[data-theme="dark"] .quiz-option.wrong { background: #2e1a17; }

.quiz-next {
  align-self: center;
  margin-top: 20px;
  padding: 12px 32px;
  border: 0;
  border-radius: 10px;
  background: var(--ink);
  color: var(--paper);
  font: 600 15px var(--font-ui);
  cursor: pointer;
}

.quiz-next[hidden] { display: none; }

/* study done */

.study-done {
  text-align: center;
  padding: 60px 24px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
}

.study-done h3 { font: 600 30px var(--font-word); }

.study-done p { font: 400 17px var(--font-text); color: var(--ink-soft); }

.study-done-score {
  font: 600 42px var(--font-word);
  color: var(--vermilion-dark);
  font-variant-numeric: tabular-nums;
}

.study-done-actions { display: flex; gap: 12px; margin-top: 8px; }

.study-done button {
  padding: 12px 26px;
  border-radius: 10px;
  border: 1px solid var(--rule);
  background: var(--paper-raised);
  font: 600 14.5px var(--font-ui);
  color: var(--ink);
  cursor: pointer;
}

.study-done button.primary { background: var(--ink); color: var(--paper); border-color: var(--ink); }

@media (max-width: 720px) {
  .flashcard { min-height: 280px; padding: 32px 22px; }
  .flashcard-word { font-size: 34px; }
  .flashcard-def { font-size: 18px; }
  .quiz-word { font-size: 30px; }
  .rate-btn { flex: 1; padding: 13px 12px; }
  .flashcard-actions { align-self: stretch; }
}