/* ============================================================
   Mathagram.org — Exercise Engine Styles
   All 6 exercise types + completion screen
   ============================================================ */

/* ----- Container & Progress ----- */
.exercise-container {
  max-width: 700px;
  margin: 0 auto;
  padding: 24px 0;
}

.exercise-progress {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-muted);
  margin-bottom: 12px;
}

.exercise-question {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.5;
  margin-bottom: 20px;
}

/* ----- Next / Finish Button ----- */
.exercise-next-btn {
  width: 100%;
  margin-top: 20px;
  padding: 14px 24px;
  font-size: 1rem;
}

/* ============================================================
   1. Multiple Choice (.mc-options)
   ============================================================ */
.mc-options {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.mc-option {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px 20px;
  background: var(--color-white);
  border: 2px solid var(--color-border);
  border-radius: var(--radius);
  font-family: var(--font-sans);
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--color-text);
  cursor: pointer;
  transition: border-color 0.2s, background 0.2s, transform 0.15s,
    box-shadow 0.2s;
  text-align: center;
  line-height: 1.4;
}

.mc-option:hover:not(:disabled) {
  border-color: var(--color-primary);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

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

.mc-option.correct {
  background: var(--color-science-bg);
  border-color: var(--color-science);
  color: var(--color-science);
}

.mc-option.wrong {
  background: var(--color-data-bg);
  border-color: var(--color-data);
  color: var(--color-data);
}

/* ============================================================
   2. Matching (.match-area)
   ============================================================ */
.match-area {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.match-col {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.match-item {
  padding: 14px 18px;
  background: var(--color-white);
  border: 2px solid var(--color-border);
  border-radius: var(--radius);
  font-size: 0.925rem;
  font-weight: 500;
  color: var(--color-text);
  cursor: pointer;
  text-align: center;
  transition: border-color 0.2s, background 0.2s, transform 0.15s;
  user-select: none;
}

.match-item:hover:not(.matched) {
  border-color: var(--color-primary);
}

.match-item.selected {
  border-color: var(--color-primary);
  background: rgba(0, 229, 200, 0.08);
  transform: scale(1.03);
}

.match-item.matched {
  background: var(--color-science-bg);
  border-color: var(--color-science);
  color: var(--color-science);
  cursor: default;
  opacity: 0.85;
}

/* Shake animation for wrong match */
@keyframes shake {
  0%,
  100% {
    transform: translateX(0);
  }
  15% {
    transform: translateX(-6px);
  }
  30% {
    transform: translateX(6px);
  }
  45% {
    transform: translateX(-4px);
  }
  60% {
    transform: translateX(4px);
  }
  75% {
    transform: translateX(-2px);
  }
}

.match-item.wrong-flash {
  animation: shake 0.5s ease;
  border-color: var(--color-data);
  background: var(--color-data-bg);
}

/* ============================================================
   3. Fill in the Blank (.fill-blank-form)
   ============================================================ */
.fill-blank-form {
  display: flex;
  gap: 12px;
  align-items: stretch;
}

.fill-blank-input {
  flex: 1;
  padding: 12px 16px;
  font-family: var(--font-mono);
  font-size: 1rem;
  color: var(--color-text);
  background: var(--color-white);
  border: 2px solid var(--color-border);
  border-radius: var(--radius);
  outline: none;
  transition: border-color 0.2s, background 0.2s;
}

.fill-blank-input:focus {
  border-color: var(--color-primary);
}

.fill-blank-input.correct {
  border-color: var(--color-science);
  background: var(--color-science-bg);
}

.fill-blank-input.wrong {
  border-color: var(--color-data);
  background: var(--color-data-bg);
}

.fill-blank-btn {
  white-space: nowrap;
}

.fill-blank-reveal {
  margin-top: 12px;
  padding: 10px 16px;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-science);
  background: var(--color-science-bg);
  border-radius: var(--radius);
}

/* ============================================================
   4. Ordering (.ordering-list)
   ============================================================ */
.ordering-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 16px;
}

.ordering-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 16px;
  background: var(--color-white);
  border: 2px solid var(--color-border);
  border-radius: var(--radius);
  transition: border-color 0.2s, background 0.2s;
}

.ordering-item.correct {
  border-color: var(--color-science);
  background: var(--color-science-bg);
}

.ordering-item.wrong {
  border-color: var(--color-data);
  background: var(--color-data-bg);
}

.ordering-num {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--color-text-secondary);
  background: var(--color-bg);
  border-radius: 50%;
  flex-shrink: 0;
}

.ordering-label {
  flex: 1;
  font-size: 0.925rem;
  font-weight: 500;
  color: var(--color-text);
}

.ordering-arrows {
  display: flex;
  flex-direction: column;
  gap: 2px;
  flex-shrink: 0;
}

.ordering-arrow {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 22px;
  font-size: 0.65rem;
  color: var(--color-text-secondary);
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
}

.ordering-arrow:hover:not(:disabled) {
  background: var(--color-primary);
  color: var(--color-text);
}

.ordering-arrow:disabled {
  opacity: 0.35;
  cursor: default;
}

.ordering-check-btn {
  width: 100%;
}

/* ============================================================
   5. True / False (.tf-buttons)
   ============================================================ */
.tf-buttons {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.tf-btn {
  padding: 20px;
  font-family: var(--font-sans);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-text);
  background: var(--color-white);
  border: 2px solid var(--color-border);
  border-radius: var(--radius);
  cursor: pointer;
  transition: border-color 0.2s, background 0.2s, transform 0.15s,
    box-shadow 0.2s;
}

.tf-btn:hover:not(:disabled) {
  border-color: var(--color-primary);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.tf-btn:disabled {
  cursor: default;
}

.tf-btn.correct {
  background: var(--color-science-bg);
  border-color: var(--color-science);
  color: var(--color-science);
}

.tf-btn.wrong {
  background: var(--color-data-bg);
  border-color: var(--color-data);
  color: var(--color-data);
}

/* ============================================================
   6. Visual Diagram (.visual-diagram)
   ============================================================ */
.visual-diagram {
  padding: 24px;
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  margin-bottom: 20px;
  text-align: center;
  overflow-x: auto;
}

.visual-diagram img,
.visual-diagram svg {
  max-width: 100%;
  height: auto;
  margin: 0 auto;
}

/* ============================================================
   Lesson Complete Screen (.lesson-complete)
   ============================================================ */
.lesson-complete {
  text-align: center;
  padding: 40px 24px;
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  max-width: 480px;
  margin: 32px auto;
  box-shadow: var(--shadow-md);
}

.lesson-complete h2 {
  font-size: 1.5rem;
  font-weight: 800;
  margin-bottom: 8px;
}

.lesson-complete .grade-display {
  font-size: 4rem;
  font-weight: 800;
  line-height: 1;
  margin: 16px 0;
}

.grade-a {
  color: var(--color-science);
}

.grade-b {
  color: #14b8a6;
}

.grade-c {
  color: var(--color-xp);
}

.grade-d {
  color: var(--color-logic);
}

.grade-f {
  color: var(--color-data);
}

.lesson-complete .stars {
  font-size: 2rem;
  letter-spacing: 4px;
  margin-bottom: 12px;
}

.lesson-complete .xp-earned {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 20px;
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-xp);
  background: rgba(234, 179, 8, 0.1);
  border-radius: var(--radius);
  margin-bottom: 16px;
}

.lesson-complete .score-text {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  margin-bottom: 24px;
}

/* ============================================================
   Error state
   ============================================================ */
.exercise-error {
  padding: 16px;
  color: var(--color-data);
  font-weight: 500;
}

/* ============================================================
   Responsive — Mobile (max-width: 768px)
   ============================================================ */
@media (max-width: 768px) {
  .exercise-container {
    padding: 16px 0;
  }

  .exercise-question {
    font-size: 1.05rem;
  }

  /* MC: single column */
  .mc-options {
    grid-template-columns: 1fr;
  }

  /* Matching: single column (stacked) */
  .match-area {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  /* Fill blank: stack */
  .fill-blank-form {
    flex-direction: column;
  }

  /* TF: single column */
  .tf-buttons {
    grid-template-columns: 1fr;
  }

  /* Lesson complete */
  .lesson-complete {
    margin: 24px 16px;
    padding: 32px 16px;
  }

  .lesson-complete .grade-display {
    font-size: 3rem;
  }
}