/* ═══════════════════════════════════════
   CSS ЗМІННІ ТА БАЗОВІ СТИЛІ
═══════════════════════════════════════ */
:root {
  --bg-primary: #0a1730;
  --bg-secondary: #0e1f3d;
  --bg-card: rgba(255,255,255,0.045);
  --bg-card-hover: rgba(255,255,255,0.075);
  --glass: rgba(255,255,255,0.06);
  --glass-border: rgba(255,255,255,0.12);
  --accent: #1e4fd6;
  --accent2: #6abf3a;
  --accent2-hover: #7bd048;
  --accent-teal: #0d8a72;
  --accent-teal-hover: #109e83;
  --accent3: #2f8fe0;
  --success: #34d399;
  --danger: #f87171;
  --warning: #fbbf24;
  --text-primary: #f4f6ff;
  --text-secondary: #93a3c4;
  --text-muted: #55658a;
  --radius: 18px;
  --radius-sm: 12px;
  --shadow: 0 8px 32px rgba(0,0,0,0.4);
  --transition: 0.25s cubic-bezier(0.4,0,0.2,1);
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

h1, h2, h3, h4 { font-weight: 800; letter-spacing: -0.01em; }
.btn, .lang-btn, .tab-btn, .mode-btn { font-family: 'Manrope', inherit; }

body {
  font-family: 'Manrope', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  overflow-x: hidden;
  position: relative;
}

/* Animated background */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background:
    linear-gradient(160deg, #0a1730 0%, #0e2249 45%, #123566 100%),
    radial-gradient(ellipse 80% 50% at 15% 15%, rgba(30,79,214,0.16) 0%, transparent 60%),
    radial-gradient(ellipse 60% 40% at 85% 75%, rgba(106,191,58,0.08) 0%, transparent 60%);
  pointer-events: none;
  z-index: 0;
}
/* Subtle dot-grid texture, echoing the main site's hero pattern */
body::after {
  content: '';
  position: fixed;
  inset: 0;
  background-image: radial-gradient(rgba(255,255,255,0.05) 1px, transparent 1px);
  background-size: 22px 22px;
  pointer-events: none;
  z-index: 0;
  opacity: 0.5;
}

/* ═══════════════════════════════════════
   GLASSMORPHISM УТИЛІТИ
═══════════════════════════════════════ */
.glass {
  background: var(--glass);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius);
}

.glass-card {
  background: var(--bg-card);
  backdrop-filter: blur(12px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius);
  transition: all var(--transition);
}

.glass-card:hover {
  background: var(--bg-card-hover);
  border-color: rgba(30,79,214,0.3);
  transform: translateY(-2px);
  box-shadow: 0 16px 48px rgba(30,79,214,0.15);
}

/* ═══════════════════════════════════════
   КНОПКИ
═══════════════════════════════════════ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 24px;
  border: none;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 700;
  cursor: pointer;
  transition: all var(--transition);
  text-decoration: none;
  white-space: nowrap;
}

.btn-primary {
  background: var(--accent2);
  color: #fff;
  box-shadow: 0 4px 16px rgba(106,191,58,0.35);
}
.btn-primary:hover { transform: translateY(-1px); box-shadow: 0 6px 22px rgba(106,191,58,0.45); background: var(--accent2-hover); }

.btn-teal {
  background: var(--accent-teal);
  color: #fff;
  box-shadow: 0 4px 16px rgba(13,138,114,0.35);
}
.btn-teal:hover { transform: translateY(-1px); background: var(--accent-teal-hover); }

.btn-ghost {
  background: rgba(255,255,255,0.06);
  color: #fff;
  border: 1px solid rgba(255,255,255,0.18);
}
.btn-ghost:hover { background: rgba(255,255,255,0.1); color: var(--text-primary); }

.btn-danger { background: rgba(248,113,113,0.15); color: var(--danger); border: 1px solid rgba(248,113,113,0.2); }
.btn-success { background: rgba(52,211,153,0.15); color: var(--success); border: 1px solid rgba(52,211,153,0.2); }

.btn-icon { width: 36px; height: 36px; padding: 0; justify-content: center; border-radius: 50%; }

/* ═══════════════════════════════════════
   INPUTS
═══════════════════════════════════════ */
.input, textarea, select {
  width: 100%;
  background: rgba(255,255,255,0.04);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-size: 15px;
  padding: 12px 16px;
  outline: none;
  transition: border-color var(--transition);
  font-family: inherit;
  resize: vertical;
}
.input:focus, textarea:focus, select:focus {
  border-color: var(--accent);
  background: rgba(30,79,214,0.05);
}
textarea { min-height: 120px; }
select option { background: #1a1a2e; }

label { display: block; font-size: 13px; color: var(--text-secondary); margin-bottom: 6px; }

/* ═══════════════════════════════════════
   ПРОГРЕС-БАР
═══════════════════════════════════════ */
.progress-bar {
  height: 6px;
  background: rgba(255,255,255,0.08);
  border-radius: 99px;
  overflow: hidden;
}
.progress-fill {
  height: 100%;
  background: var(--accent2);
  border-radius: 99px;
  transition: width 0.4s ease;
}

/* ═══════════════════════════════════════
   ЛОГОТИП (нижній лівий кут)
═══════════════════════════════════════ */
#company-brand {
  position: fixed;
  bottom: 16px;
  left: 16px;
  z-index: 1000;
  opacity: 0.3;
  pointer-events: none;
  transition: opacity var(--transition);
}
#company-brand:hover { opacity: 0.3; }
#company-logo {
  width: 77px;
  height: auto;
  display: block;
}
#company-logo img { width: 100%; height: auto; display: block; }
#company-name { display: none; }

/* ═══════════════════════════════════════
   ПЕРЕМИКАЧ МОВИ (нижній правий кут)
═══════════════════════════════════════ */
.lang-switch {
  position: fixed;
  bottom: 16px;
  right: 16px;
  z-index: 1000;
  display: flex;
  gap: 4px;
  background: var(--bg-card);
  backdrop-filter: blur(16px);
  border: 1px solid var(--glass-border);
  border-radius: 99px;
  padding: 4px;
}
.lang-btn {
  border: none;
  background: transparent;
  color: var(--text-secondary);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.03em;
  padding: 7px 14px;
  border-radius: 99px;
  cursor: pointer;
  transition: all var(--transition);
}
.lang-btn:hover { color: var(--text-primary); }
.lang-btn.active {
  background: var(--accent);
  color: #fff;
}
@media (max-width: 600px) {
  .lang-switch { bottom: 12px; right: 12px; }
  .lang-btn { padding: 6px 11px; font-size: 11px; }
}

/* ═══════════════════════════════════════
   ЕКРАНИ
═══════════════════════════════════════ */
.screen {
  display: none;
  min-height: 100vh;
  position: relative;
  z-index: 1;
  padding: 0 0 100px;
  animation: fadeIn 0.3s ease;
}
.screen.active { display: block; }

@keyframes fadeIn { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: translateY(0); } }

/* ═══════════════════════════════════════
   HEADER
═══════════════════════════════════════ */
.header {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 20px 24px;
  border-bottom: 1px solid var(--glass-border);
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(10,23,48,0.75);
  backdrop-filter: blur(20px);
}
.back-btn {
  width: 36px; height: 36px;
  background: var(--glass);
  border: 1px solid var(--glass-border);
  border-radius: 50%;
  color: var(--text-secondary);
  cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  font-size: 18px;
  transition: all var(--transition);
  flex-shrink: 0;
}
.back-btn:hover { background: var(--bg-card-hover); color: var(--text-primary); }
.header h2 { font-size: 18px; font-weight: 800; }

/* ═══════════════════════════════════════
   ГОЛОВНИЙ ЕКРАН
═══════════════════════════════════════ */
#screen-home .hero {
  text-align: center;
  padding: 56px 24px 40px;
}
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.14);
  border-radius: 999px;
  padding: 7px 16px 7px 7px;
  font-size: 13px;
  font-weight: 700;
  color: #fff;
  margin-bottom: 22px;
}
.hero-badge .dot {
  width: 22px; height: 22px;
  border-radius: 50%;
  background: var(--accent2);
  display: flex; align-items: center; justify-content: center;
  font-size: 12px;
  flex-shrink: 0;
}
#screen-home .hero h1 {
  font-size: clamp(30px, 6vw, 54px);
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  line-height: 1.15;
  margin-bottom: 14px;
}
#screen-home .hero h1 span { color: var(--accent2); }
#screen-home .hero p { color: var(--text-secondary); font-size: 16px; max-width: 500px; margin: 0 auto; font-weight: 500; }

.hero-stats {
  display: flex;
  justify-content: center;
  gap: 32px;
  flex-wrap: wrap;
  margin-top: 28px;
}
.hero-stats .stat b {
  display: block;
  font-size: 24px;
  font-weight: 800;
  color: #fff;
}
.hero-stats .stat span {
  font-size: 12px;
  color: var(--text-secondary);
  font-weight: 600;
}

.home-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 16px;
  padding: 0 24px;
  max-width: 1000px;
  margin: 0 auto;
}

.home-card {
  background: var(--bg-card);
  border: 1px solid var(--glass-border);
  backdrop-filter: blur(12px);
  border-radius: 20px;
  padding: 26px 22px;
  cursor: pointer;
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
}
.home-card::before {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--card-color, var(--accent));
  opacity: 0.05;
  transition: opacity var(--transition);
}
.home-card:hover {
  background: var(--bg-card-hover);
  border-color: var(--card-color, var(--accent));
  transform: translateY(-3px);
  box-shadow: 0 20px 48px rgba(0,0,0,0.3);
}
.home-card:hover::before { opacity: 0.12; }
.card-icon {
  width: 48px;
  height: 48px;
  border-radius: 14px;
  background: var(--card-color, var(--accent));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
  margin-bottom: 18px;
  position: relative;
  z-index: 1;
  box-shadow: 0 6px 16px rgba(0,0,0,0.25);
}
.home-card h3 { font-size: 18px; font-weight: 800; margin-bottom: 6px; position: relative; z-index: 1; }
.home-card p { font-size: 13px; color: var(--text-secondary); line-height: 1.5; font-weight: 500; position: relative; z-index: 1; }
.card-badge {
  display: inline-block;
  margin-top: 14px;
  font-size: 11px;
  font-weight: 700;
  padding: 4px 11px;
  border-radius: 99px;
  background: rgba(255,255,255,0.08);
  border: 1px solid rgba(255,255,255,0.1);
  color: var(--text-secondary);
  position: relative;
  z-index: 1;
}

.home-card.disabled {
  cursor: not-allowed;
  opacity: 0.5;
  filter: grayscale(0.3);
}
.home-card.disabled:hover {
  transform: none;
  box-shadow: none;
  border-color: var(--glass-border);
  background: var(--bg-card);
}

.section-label {
  max-width: 1000px;
  margin: 36px auto 14px;
  padding: 0 24px;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-secondary);
}
@media (max-width: 600px) { .section-label { padding: 0 16px; } }

/* ═══════════════════════════════════════
   НАЛАШТУВАННЯ МАТЕРІАЛУ
═══════════════════════════════════════ */
.material-setup { padding: 24px; max-width: 700px; margin: 0 auto; }
.material-setup h3 { font-size: 16px; margin-bottom: 16px; color: var(--text-secondary); }

.tab-bar {
  display: flex;
  gap: 4px;
  background: rgba(255,255,255,0.04);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
  padding: 4px;
  margin-bottom: 16px;
}
.tab-btn {
  flex: 1;
  padding: 8px 12px;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  border-radius: 8px;
  cursor: pointer;
  font-size: 13px;
  transition: all var(--transition);
}
.tab-btn.active {
  background: var(--accent);
  color: #fff;
}

.format-hint {
  font-size: 12px;
  color: var(--text-muted);
  margin-top: 6px;
  font-family: monospace;
  background: rgba(255,255,255,0.03);
  padding: 8px 12px;
  border-radius: 8px;
  border-left: 2px solid var(--accent);
}

/* ═══════════════════════════════════════
   ВИБІР ВПРАВИ
═══════════════════════════════════════ */
.exercise-picker {
  padding: 24px;
  max-width: 700px;
  margin: 0 auto;
}
.exercise-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 24px;
}
.exercise-item {
  display: flex;
  align-items: center;
  gap: 16px;
  background: var(--bg-card);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
  padding: 16px 20px;
  cursor: pointer;
  transition: all var(--transition);
}
.exercise-item:hover {
  background: var(--bg-card-hover);
  border-color: var(--accent);
}
.exercise-item .ex-icon { font-size: 24px; }
.exercise-item .ex-info h4 { font-size: 15px; font-weight: 500; }
.exercise-item .ex-info p { font-size: 12px; color: var(--text-secondary); margin-top: 2px; }

/* Saved sets */
.sets-list { display: flex; flex-direction: column; gap: 8px; margin-top: 12px; }
.set-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--bg-card);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
  padding: 12px 16px;
}
.set-item span { font-size: 14px; }
.set-item .set-meta { font-size: 12px; color: var(--text-secondary); }

/* ═══════════════════════════════════════
   ВПРАВИ
═══════════════════════════════════════ */
.exercise-area {
  padding: 24px;
  max-width: 700px;
  margin: 0 auto;
}

.streak-bar {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 20px;
  font-size: 14px;
  color: var(--warning);
  font-weight: 600;
}

.word-card {
  background: var(--glass);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius);
  padding: 40px 32px;
  text-align: center;
  margin-bottom: 24px;
  position: relative;
}
.word-card .word-main { font-size: clamp(28px, 6vw, 48px); font-weight: 700; margin-bottom: 8px; }
.word-card .word-sub { font-size: 14px; color: var(--text-secondary); }
.word-card .speak-btn {
  position: absolute;
  top: 16px; right: 16px;
  background: rgba(30,79,214,0.15);
  border: none;
  border-radius: 50%;
  width: 36px; height: 36px;
  display: flex; align-items: center; justify-content: center;
  cursor: pointer;
  font-size: 16px;
  transition: all var(--transition);
  color: var(--accent2);
}
.word-card .speak-btn:hover { background: rgba(30,79,214,0.3); }

.answer-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  margin-bottom: 16px;
}
.answer-btn {
  padding: 14px 16px;
  background: var(--bg-card);
  border: 1.5px solid var(--glass-border);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-size: 14px;
  cursor: pointer;
  transition: all var(--transition);
  text-align: left;
}
.answer-btn:hover { background: var(--bg-card-hover); border-color: var(--accent); }
.answer-btn.selected { border-color: var(--accent); background: rgba(30,79,214,0.14); }
.answer-btn.correct { background: rgba(52,211,153,0.15); border-color: var(--success); color: var(--success); }
.answer-btn.wrong { background: rgba(248,113,113,0.15); border-color: var(--danger); color: var(--danger); }
.audio-quiz-grid { display: flex; flex-direction: column; gap: 10px; margin-bottom: 16px; }
.audio-quiz-btn { display: flex; align-items: center; justify-content: center; gap: 8px; font-weight: 700; text-align: center; }
.audio-quiz-btn .quiz-play-icon { font-size: 16px; }

.feedback-box {
  padding: 14px 16px;
  border-radius: var(--radius-sm);
  margin: 12px 0;
  font-size: 14px;
  line-height: 1.5;
  display: none;
}
.feedback-box.show { display: block; }
.feedback-box.success { background: rgba(52,211,153,0.1); border: 1px solid rgba(52,211,153,0.2); color: var(--success); }
.feedback-box.error { background: rgba(248,113,113,0.1); border: 1px solid rgba(248,113,113,0.2); color: var(--danger); }
.feedback-box.warning { background: rgba(251,191,36,0.1); border: 1px solid rgba(251,191,36,0.2); color: var(--warning); }

/* Matching game */
.match-area {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}
.match-col { display: flex; flex-direction: column; gap: 8px; }
.match-item {
  padding: 12px 16px;
  background: var(--bg-card);
  border: 1.5px solid var(--glass-border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 14px;
  transition: all var(--transition);
  text-align: center;
}
.match-item:hover { border-color: var(--accent2); background: var(--bg-card-hover); }
.match-item.selected { border-color: var(--accent); background: rgba(30,79,214,0.12); }
.match-item.matched { border-color: var(--success); background: rgba(52,211,153,0.1); color: var(--success); pointer-events: none; }
.match-item.wrong-match { border-color: var(--danger); animation: shake 0.3s ease; }

@keyframes shake {
  0%,100%{transform:translateX(0)}
  25%{transform:translateX(-6px)}
  75%{transform:translateX(6px)}
}

/* Word order */
.word-chips { display: flex; flex-wrap: wrap; gap: 8px; margin: 16px 0; min-height: 48px; }
.chip {
  padding: 8px 14px;
  background: rgba(30,79,214,0.12);
  border: 1px solid rgba(30,79,214,0.2);
  border-radius: 99px;
  font-size: 14px;
  cursor: pointer;
  transition: all var(--transition);
  user-select: none;
}
.chip:hover { background: rgba(30,79,214,0.2); }
.chip.used { opacity: 0.3; pointer-events: none; }
.sentence-slots {
  min-height: 48px;
  background: rgba(255,255,255,0.03);
  border: 1.5px dashed var(--glass-border);
  border-radius: var(--radius-sm);
  padding: 8px 12px;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 12px;
  align-items: center;
}
.chip-placed {
  padding: 6px 12px;
  background: rgba(124,192,29,0.15);
  border: 1px solid rgba(124,192,29,0.3);
  border-radius: 99px;
  font-size: 14px;
  cursor: pointer;
}
.chip-placed:hover { background: rgba(248,113,113,0.15); border-color: var(--danger); }

/* Gap fill */
.gap-sentence { font-size: 18px; line-height: 2; margin: 20px 0; }
.gap-input {
  display: inline-block;
  width: 140px;
  background: rgba(30,79,214,0.08);
  border: none;
  border-bottom: 2px solid var(--accent);
  color: var(--text-primary);
  font-size: 16px;
  padding: 4px 8px;
  outline: none;
  text-align: center;
  border-radius: 0;
  font-family: inherit;
  min-width: 80px;
}

/* ═══════════════════════════════════════
   СТАТИСТИКА
═══════════════════════════════════════ */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 12px;
  padding: 24px;
  max-width: 900px;
  margin: 0 auto;
}
.stat-card {
  background: var(--bg-card);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius);
  padding: 20px;
  text-align: center;
}
.stat-card .stat-val { font-size: 32px; font-weight: 700; margin-bottom: 4px; }
.stat-card .stat-lbl { font-size: 12px; color: var(--text-secondary); }

.history-list { padding: 0 24px; max-width: 900px; margin: 0 auto; }
.history-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 0;
  border-bottom: 1px solid rgba(255,255,255,0.05);
  font-size: 14px;
}
.history-item:last-child { border-bottom: none; }
.day-chart {
  display: flex;
  align-items: flex-end;
  gap: 4px;
  height: 60px;
  padding: 24px;
  max-width: 900px;
  margin: 0 auto 8px;
}
.day-bar {
  flex: 1;
  background: rgba(30,79,214,0.2);
  border-radius: 4px 4px 0 0;
  transition: all var(--transition);
  position: relative;
  min-height: 4px;
}
.day-bar:hover { background: rgba(30,79,214,0.5); }
.day-bar span {
  position: absolute;
  bottom: -20px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 10px;
  color: var(--text-muted);
  white-space: nowrap;
}

/* ═══════════════════════════════════════
   АУДІЮВАННЯ
═══════════════════════════════════════ */
.audio-play-btn {
  width: 80px; height: 80px;
  border-radius: 50%;
  background: var(--accent);
  border: none;
  color: white;
  font-size: 32px;
  cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  margin: 24px auto;
  box-shadow: 0 8px 32px rgba(30,79,214,0.4);
  transition: all var(--transition);
}
.audio-play-btn:hover { transform: scale(1.05); box-shadow: 0 12px 40px rgba(30,79,214,0.6); }
.audio-play-btn:active { transform: scale(0.98); }

/* ═══════════════════════════════════════
   МОДУЛЬ "РАХУВАННЯ" (математика)
═══════════════════════════════════════ */
.math-cat-tabs {
  display: flex;
  gap: 8px;
  margin-bottom: 22px;
  flex-wrap: wrap;
}
.math-cat-btn {
  flex: 1;
  min-width: 120px;
  padding: 12px 14px;
  border: 1px solid var(--glass-border);
  background: var(--bg-card);
  color: var(--text-secondary);
  border-radius: 14px;
  font-family: 'Manrope', inherit;
  font-weight: 700;
  font-size: 13px;
  cursor: pointer;
  transition: all var(--transition);
  text-align: center;
}
.math-cat-btn.active {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.math-section-title {
  font-size: 13px;
  font-weight: 700;
  color: var(--text-secondary);
  margin: 18px 0 10px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.math-section-title:first-child { margin-top: 0; }

.chip-group { display: flex; flex-wrap: wrap; gap: 8px; }
.chip { position: relative; cursor: pointer; }
.chip input { position: absolute; opacity: 0; width: 0; height: 0; }
.chip span {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 9px 16px;
  border-radius: 999px;
  background: rgba(255,255,255,0.05);
  border: 1px solid var(--glass-border);
  color: var(--text-secondary);
  font-size: 13px;
  font-weight: 700;
  transition: all var(--transition);
  user-select: none;
}
.chip:hover span { border-color: var(--accent2); }
.chip input:checked + span {
  background: var(--accent2);
  border-color: var(--accent2);
  color: #fff;
}
.chip.chip-blue input:checked + span {
  background: var(--accent);
  border-color: var(--accent);
}

.math-count-row {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-top: 26px;
  padding-top: 20px;
  border-top: 1px solid var(--glass-border);
  flex-wrap: wrap;
}
.math-count-row label { font-size: 13px; font-weight: 700; color: var(--text-secondary); }
.math-count-row input[type=number] {
  width: 76px;
  text-align: center;
  padding: 9px 6px;
  border-radius: 10px;
  border: 1px solid var(--glass-border);
  background: rgba(255,255,255,0.06);
  color: #fff;
  font-size: 15px;
  font-weight: 700;
}
.math-count-row input[type=number]:focus { outline: none; border-color: var(--accent); }

.diff-slider-row { display: flex; align-items: center; gap: 12px; margin-bottom: 4px; }
.diff-slider {
  flex: 1;
  -webkit-appearance: none;
  appearance: none;
  height: 6px;
  border-radius: 99px;
  background: linear-gradient(90deg, var(--accent2) 0%, var(--accent2) var(--fill,50%), rgba(255,255,255,0.1) var(--fill,50%), rgba(255,255,255,0.1) 100%);
  outline: none;
}
.diff-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 20px; height: 20px;
  border-radius: 50%;
  background: #fff;
  border: 3px solid var(--accent2);
  cursor: pointer;
  box-shadow: 0 2px 6px rgba(0,0,0,0.4);
}
.diff-slider::-moz-range-thumb {
  width: 20px; height: 20px;
  border-radius: 50%;
  background: #fff;
  border: 3px solid var(--accent2);
  cursor: pointer;
}
.diff-badge {
  min-width: 28px;
  text-align: center;
  padding: 4px 9px;
  border-radius: 8px;
  background: var(--accent2);
  color: #fff;
  font-weight: 800;
  font-size: 13px;
}
.diff-desc {
  font-size: 12px;
  color: var(--text-secondary);
  margin-bottom: 16px;
  font-weight: 600;
}

.math-problem {
  background: var(--bg-card);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius);
  padding: 36px 20px;
  text-align: center;
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 10px;
  font-size: 30px;
  font-weight: 800;
  color: #fff;
  min-height: 100px;
}
.math-problem.system-eq { flex-direction: column; gap: 14px; }
.math-problem .op { color: var(--accent2); margin: 0 2px; }
/* Власний символ ділення — надійний рендер незалежно від шрифту (юнікод-÷ в деяких шрифтах "їде") */
.op-div {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.24em;
  vertical-align: middle;
  margin: 0 4px;
}
.op-div .dot { width: 0.15em; height: 0.15em; border-radius: 50%; background: currentColor; flex-shrink: 0; }
.op-div .bar { width: 0.7em; height: 0.14em; border-radius: 2px; background: currentColor; }
.math-prompt-text {
  font-size: 17px;
  font-weight: 600;
  color: var(--text-primary);
  text-align: center;
  margin-bottom: 20px;
  line-height: 1.5;
}
.math-prompt-text b { color: var(--accent2); }

/* Візуальний дріб — риска, чисельник над знаменником */
.frac-display {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  vertical-align: middle;
  line-height: 1.25;
}
.frac-display .fd-num, .frac-display .fd-den {
  padding: 0 6px;
  white-space: nowrap;
}
.frac-display .fd-num { border-bottom: 3px solid currentColor; padding-bottom: 3px; }
.frac-display .fd-den { padding-top: 3px; }
.frac-display .fd-whole { font-size: inherit; }

/* Зручне введення дробу: чисельник / риска / знаменник */
.frac-input {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  vertical-align: middle;
  gap: 4px;
}
.frac-input input {
  width: 68px;
  text-align: center;
  background: rgba(255,255,255,0.07);
  border: 1px solid var(--glass-border);
  border-radius: 10px;
  color: #fff;
  font-size: 18px;
  font-weight: 700;
  font-family: 'Manrope', inherit;
  padding: 8px 4px;
}
.frac-input input:focus { outline: none; border-color: var(--accent2); }
.frac-input .fi-bar { width: 100%; height: 3px; background: var(--text-secondary); border-radius: 2px; }
.frac-input.wide input { width: 96px; font-size: 15px; }

.math-answer-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 16px;
}
.math-answer-row .eq-sign { font-size: 26px; font-weight: 800; color: var(--text-secondary); }
.math-answer-row input[type=text].math-plain-input {
  width: 140px;
  text-align: center;
  background: rgba(255,255,255,0.07);
  border: 1px solid var(--glass-border);
  border-radius: 12px;
  color: #fff;
  font-size: 20px;
  font-weight: 700;
  font-family: 'Manrope', inherit;
  padding: 12px 10px;
}
.math-answer-row input[type=text].math-plain-input:focus { outline: none; border-color: var(--accent2); }
.math-hint {
  text-align: center;
  font-size: 12px;
  color: var(--text-muted);
  margin-bottom: 14px;
}

/* ═══════════════════════════════════════
   ГЕОМЕТРІЯ — SVG-СХЕМИ
═══════════════════════════════════════ */
.geo-figure-box {
  background: var(--bg-card);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius);
  padding: 20px;
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
}
.geo-svg { width: 100%; max-width: 300px; height: auto; display: block; }
.geo-shape { fill: rgba(106,191,58,0.14); stroke: var(--accent2); stroke-width: 3; stroke-linejoin: round; }
.geo-shape2 { fill: rgba(30,79,214,0.16); stroke: var(--accent); stroke-width: 3; stroke-linejoin: round; }
.geo-dash { stroke: var(--accent3); stroke-width: 2; stroke-dasharray: 6 5; fill: none; }
.geo-thin { stroke: rgba(255,255,255,0.45); stroke-width: 1.5; fill: none; }
.geo-label {
  fill: #fff;
  font-family: 'Manrope', sans-serif;
  font-weight: 800;
  font-size: 17px;
  text-anchor: middle;
  dominant-baseline: middle;
}
.geo-label-sm {
  fill: var(--text-secondary);
  font-family: 'Manrope', sans-serif;
  font-weight: 700;
  font-size: 13px;
  text-anchor: middle;
  dominant-baseline: middle;
}
.geo-unknown { fill: var(--accent2); font-weight: 900; }
.geo-center-label {
  fill: #fff;
  font-family: 'Manrope', sans-serif;
  font-weight: 800;
  font-size: 19px;
  text-anchor: middle;
  dominant-baseline: middle;
}
.geo-right-marker { fill: none; stroke: rgba(255,255,255,0.7); stroke-width: 2; }

/* ═══════════════════════════════════════
   RESULTS SCREEN
═══════════════════════════════════════ */
.results-screen {
  text-align: center;
  padding: 40px 24px;
  max-width: 500px;
  margin: 0 auto;
}
.results-emoji { font-size: 64px; margin-bottom: 16px; }
.results-title { font-size: 28px; font-weight: 700; margin-bottom: 8px; }
.results-subtitle { color: var(--text-secondary); font-size: 15px; margin-bottom: 32px; }
.results-stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-bottom: 28px;
}
.r-stat {
  background: var(--bg-card);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
  padding: 16px;
}
.r-stat .val { font-size: 28px; font-weight: 700; color: var(--accent2); }
.r-stat .lbl { font-size: 12px; color: var(--text-secondary); margin-top: 4px; }


/* ═══════════════════════════════════════
   RESPONSIVE
═══════════════════════════════════════ */
@media (max-width: 600px) {
  .home-grid { grid-template-columns: 1fr; padding: 0 16px; }
  .answer-grid { grid-template-columns: 1fr; }
  .match-area { grid-template-columns: 1fr; }
  .header { padding: 16px; }
  .exercise-area, .material-setup, .exercise-picker { padding: 16px; }
  #company-brand { bottom: 12px; left: 12px; }
  .results-stats { grid-template-columns: 1fr; }
}

/* Mode toggle */
.mode-toggle {
  display: flex;
  gap: 4px;
  background: rgba(255,255,255,0.04);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
  padding: 4px;
  margin-bottom: 16px;
  flex-wrap: wrap;
}
.mode-btn {
  flex: 1;
  padding: 7px 10px;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  border-radius: 6px;
  cursor: pointer;
  font-size: 12px;
  transition: all var(--transition);
  white-space: nowrap;
}
.mode-btn.active { background: rgba(30,79,214,0.2); color: var(--accent2); }

/* Toast */
.toast {
  position: fixed;
  bottom: 80px;
  right: 20px;
  background: var(--glass);
  backdrop-filter: blur(20px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
  padding: 12px 18px;
  font-size: 14px;
  z-index: 9999;
  transform: translateX(120%);
  transition: transform 0.3s ease;
  max-width: 280px;
}
.toast.show { transform: translateX(0); }
.toast.success { border-color: rgba(52,211,153,0.3); }
.toast.error { border-color: rgba(248,113,113,0.3); }

/* ═══════════════════════════════════════
   SCROLLBAR
═══════════════════════════════════════ */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.1); border-radius: 99px; }