/* ═══════════════════════════════════════════════════════════
   QUIZ BUZZERS — Question Bank
   Custom CSS — Dark/Light Theme
   ═══════════════════════════════════════════════════════════ */

/* ── FONTS & ROOT VARIABLES ── */
@import url('https://fonts.googleapis.com/css2?family=Playfair+Display:wght@700;900&family=DM+Mono:wght@300;400;500&family=DM+Sans:wght@300;400;500;600&display=swap');

:root {
  /* Dark theme (default) */
  --bg-base:       #0e0f14;
  --bg-surface:    #15161d;
  --bg-elevated:   #1c1e28;
  --bg-hover:      #23253200;
  --bg-row-alt:    #13141a;
  --bg-row-hover:  #1e2130;

  --accent:        #f0a500;
  --accent-dim:    #c48400;
  --accent-glow:   rgba(240,165,0,0.15);
  --accent-text:   #fff8e6;

  --text-primary:  #e8eaf0;
  --text-secondary:#8b90a8;
  --text-muted:    #4a4f66;
  --text-inverse:  #0e0f14;

  --border:        rgba(255,255,255,0.07);
  --border-strong: rgba(255,255,255,0.14);

  --correct:       #22c55e;
  --incorrect:     #ef4444;
  --correct-bg:    rgba(34,197,94,0.1);
  --incorrect-bg:  rgba(239,68,68,0.1);

  --shadow-sm:     0 2px 8px rgba(0,0,0,0.4);
  --shadow-md:     0 4px 20px rgba(0,0,0,0.5);
  --shadow-lg:     0 8px 40px rgba(0,0,0,0.6);

  --font-display:  'Playfair Display', Georgia, serif;
  --font-body:     'DM Sans', system-ui, sans-serif;
  --font-mono:     'DM Mono', 'Courier New', monospace;

  --radius-sm:     6px;
  --radius-md:     10px;
  --radius-lg:     16px;

  --transition:    0.18s ease;
}

[data-theme="light"] {
  --bg-base:       #f4f5f9;
  --bg-surface:    #ffffff;
  --bg-elevated:   #f0f1f7;
  --bg-row-alt:    #f8f9fc;
  --bg-row-hover:  #eef0f8;

  --accent:        #d4890a;
  --accent-dim:    #b37208;
  --accent-glow:   rgba(212,137,10,0.12);
  --accent-text:   #3d2000;

  --text-primary:  #1a1c2e;
  --text-secondary:#505470;
  --text-muted:    #9499b8;
  --text-inverse:  #ffffff;

  --border:        rgba(0,0,0,0.08);
  --border-strong: rgba(0,0,0,0.16);

  --shadow-sm:     0 2px 8px rgba(0,0,0,0.08);
  --shadow-md:     0 4px 20px rgba(0,0,0,0.12);
  --shadow-lg:     0 8px 40px rgba(0,0,0,0.16);
}

/* ── RESET & BASE ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { font-size: 15px; scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  background: var(--bg-base);
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.6;
  transition: background var(--transition), color var(--transition);
}

/* ── SCROLLBAR ── */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: var(--bg-base); }
::-webkit-scrollbar-thumb { background: var(--text-muted); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-secondary); }


/* ═══════════════════════════════════
   HEADER
   ═══════════════════════════════════ */
.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 28px;
  background: var(--bg-surface);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-sm);
}

.header-left { display: flex; align-items: center; gap: 14px; }

.logo-mark {
  width: 40px; height: 40px;
  background: var(--accent);
  color: var(--text-inverse);
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 900;
  display: flex; align-items: center; justify-content: center;
  border-radius: var(--radius-sm);
  letter-spacing: -0.5px;
  flex-shrink: 0;
}

.site-title {
  font-family: var(--font-display);
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.3px;
  line-height: 1.1;
}

.site-subtitle {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--text-secondary);
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.header-right { display: flex; align-items: center; gap: 10px; }

.stats-pill {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--accent);
  background: var(--accent-glow);
  border: 1px solid var(--accent-dim);
  padding: 4px 12px;
  border-radius: 999px;
}

.icon-btn {
  width: 36px; height: 36px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  font-size: 1rem;
  transition: all var(--transition);
}
.icon-btn:hover { border-color: var(--accent); color: var(--accent); background: var(--accent-glow); }

.theme-icon { line-height: 1; }


/* ═══════════════════════════════════
   TOOLBAR
   ═══════════════════════════════════ */
.toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 28px;
  background: var(--bg-surface);
  border-bottom: 1px solid var(--border);
  gap: 12px;
  flex-wrap: wrap;
}

.mode-tabs { display: flex; gap: 4px; }

.mode-tab {
  display: flex; align-items: center; gap: 6px;
  padding: 7px 16px;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  background: transparent;
  color: var(--text-secondary);
  font-family: var(--font-body);
  font-size: 0.85rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition);
}
.mode-tab:hover { background: var(--bg-elevated); color: var(--text-primary); }
.mode-tab.active {
  background: var(--accent-glow);
  border-color: var(--accent);
  color: var(--accent);
}
.tab-icon { font-size: 0.9rem; }

.toolbar-right { display: flex; gap: 8px; }

.action-btn {
  padding: 7px 14px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-strong);
  background: var(--bg-elevated);
  color: var(--text-secondary);
  font-family: var(--font-body);
  font-size: 0.82rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition);
  white-space: nowrap;
}
.action-btn:hover { border-color: var(--accent); color: var(--accent); background: var(--accent-glow); }
.action-btn:active { transform: scale(0.97); }


/* ═══════════════════════════════════
   FILTERS BAR
   ═══════════════════════════════════ */
.filters-bar {
  display: flex;
  align-items: flex-end;
  gap: 12px;
  padding: 14px 28px;
  background: var(--bg-surface);
  border-bottom: 1px solid var(--border);
  flex-wrap: wrap;
}

.filter-group { display: flex; flex-direction: column; gap: 4px; }

.filter-label {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
}

.filter-input,
.filter-select {
  height: 34px;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  background: var(--bg-elevated);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 0.84rem;
  padding: 0 10px;
  transition: border-color var(--transition), background var(--transition);
  outline: none;
}
.filter-input:focus,
.filter-select:focus { border-color: var(--accent); background: var(--bg-elevated); box-shadow: 0 0 0 2px var(--accent-glow); }

.filter-select { padding-right: 28px; appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6'%3E%3Cpath d='M0 0l5 6 5-6z' fill='%238b90a8'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 8px center;
  cursor: pointer;
}

.search-wrap { position: relative; }
.search-input { width: 240px; padding-right: 28px; }
.search-clear {
  position: absolute; right: 8px; top: 50%; transform: translateY(-50%);
  font-size: 0.75rem; color: var(--text-muted); cursor: pointer;
  display: none;
}
.search-clear.visible { display: block; }
.search-clear:hover { color: var(--accent); }

.clear-btn {
  height: 34px;
  padding: 0 14px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-strong);
  background: transparent;
  color: var(--text-muted);
  font-family: var(--font-body);
  font-size: 0.82rem;
  cursor: pointer;
  transition: all var(--transition);
  align-self: flex-end;
}
.clear-btn:hover { color: var(--incorrect); border-color: var(--incorrect); background: var(--incorrect-bg); }


/* ═══════════════════════════════════
   COLUMN PANEL
   ═══════════════════════════════════ */
.col-panel {
  padding: 14px 28px;
  background: var(--bg-surface);
  border-bottom: 1px solid var(--border);
  animation: slideDown 0.15s ease;
}
@keyframes slideDown { from { opacity:0; transform:translateY(-6px); } to { opacity:1; transform:translateY(0); } }

.col-panel-title {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  margin-bottom: 10px;
}

.col-checks { display: flex; flex-wrap: wrap; gap: 8px; }

.col-check-label {
  display: flex; align-items: center; gap: 6px;
  padding: 5px 12px;
  border-radius: 999px;
  border: 1px solid var(--border-strong);
  background: var(--bg-elevated);
  color: var(--text-secondary);
  font-size: 0.8rem;
  cursor: pointer;
  transition: all var(--transition);
  user-select: none;
}
.col-check-label:hover { border-color: var(--accent); color: var(--accent); }
.col-check-label input { display: none; }
.col-check-label.checked { background: var(--accent-glow); border-color: var(--accent); color: var(--accent); }


/* ═══════════════════════════════════
   MAIN CONTENT
   ═══════════════════════════════════ */
.main-content { padding: 20px 28px 40px; }

.mode-section { display: none; }
.mode-section.active { display: block; }


/* ═══════════════════════════════════
   TABLE MODE
   ═══════════════════════════════════ */
.table-wrapper {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-md);
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.84rem;
}

.data-table thead {
  background: var(--bg-elevated);
  position: sticky;
  top: 0;
  z-index: 10;
}

.data-table th {
  padding: 12px 14px;
  text-align: left;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-secondary);
  border-bottom: 1px solid var(--border-strong);
  white-space: nowrap;
  user-select: none;
}

.data-table th.sortable { cursor: pointer; }
.data-table th.sortable:hover { color: var(--accent); background: var(--accent-glow); }

.sort-indicator {
  display: inline-block;
  margin-left: 5px;
  opacity: 0.3;
  font-size: 0.7rem;
}
th.sort-asc .sort-indicator,
th.sort-desc .sort-indicator { opacity: 1; color: var(--accent); }

.data-table tbody tr {
  border-bottom: 1px solid var(--border);
  transition: background var(--transition);
}
.data-table tbody tr:nth-child(even) { background: var(--bg-row-alt); }
.data-table tbody tr:hover { background: var(--bg-row-hover); }

.data-table td {
  padding: 11px 14px;
  color: var(--text-primary);
  vertical-align: top;
  max-width: 400px;
}

.data-table td.col-num {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-muted);
  white-space: nowrap;
}

.data-table td.col-question { max-width: 480px; line-height: 1.5; }
.data-table td.col-answer { font-weight: 500; color: var(--accent); }

.subject-badge {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  padding: 2px 8px;
  border-radius: 999px;
  background: var(--bg-elevated);
  border: 1px solid var(--border-strong);
  color: var(--text-secondary);
  white-space: nowrap;
}

.highlight {
  background: var(--accent);
  color: var(--text-inverse);
  border-radius: 2px;
  padding: 0 1px;
}

/* Empty state */
.empty-state {
  padding: 60px 20px;
  text-align: center;
  color: var(--text-muted);
}
.empty-icon { font-size: 2.5rem; display: block; margin-bottom: 12px; }

/* Pagination */
.pagination {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 0 0;
  flex-wrap: wrap;
  gap: 10px;
}
.page-info {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
}
.page-controls { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }

.page-btn {
  height: 32px;
  padding: 0 12px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-strong);
  background: var(--bg-elevated);
  color: var(--text-secondary);
  font-family: var(--font-body);
  font-size: 0.8rem;
  cursor: pointer;
  transition: all var(--transition);
}
.page-btn:hover:not(:disabled) { border-color: var(--accent); color: var(--accent); }
.page-btn:disabled { opacity: 0.35; cursor: not-allowed; }

.page-nums { display: flex; gap: 4px; }
.page-num-btn {
  width: 32px; height: 32px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-strong);
  background: var(--bg-elevated);
  color: var(--text-secondary);
  font-size: 0.8rem;
  font-family: var(--font-mono);
  cursor: pointer;
  transition: all var(--transition);
  display: flex; align-items: center; justify-content: center;
}
.page-num-btn:hover { border-color: var(--accent); color: var(--accent); }
.page-num-btn.active { background: var(--accent); border-color: var(--accent); color: var(--text-inverse); font-weight: 500; }
.page-ellipsis { padding: 0 4px; color: var(--text-muted); font-size: 0.8rem; display:flex;align-items:center; }


/* ═══════════════════════════════════
   FLASHCARD MODE
   ═══════════════════════════════════ */
.flashcard-container {
  max-width: 700px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.fc-header { display: flex; align-items: center; justify-content: space-between; }

.fc-counter {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.fc-controls { display: flex; gap: 8px; }

.flashcard {
  height: 320px;
  perspective: 1200px;
  cursor: pointer;
  outline: none;
}
.flashcard:focus { outline: 2px solid var(--accent); outline-offset: 4px; border-radius: var(--radius-lg); }

.fc-inner {
  width: 100%; height: 100%;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 0.5s cubic-bezier(0.4, 0, 0.2, 1);
  border-radius: var(--radius-lg);
}
.flashcard.flipped .fc-inner { transform: rotateY(180deg); }

.fc-front, .fc-back {
  position: absolute; inset: 0;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-strong);
  padding: 36px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  box-shadow: var(--shadow-md);
  overflow: auto;
}

.fc-front {
  background: linear-gradient(135deg, var(--bg-surface) 0%, var(--bg-elevated) 100%);
}
.fc-back {
  background: linear-gradient(135deg, var(--accent-glow) 0%, var(--bg-elevated) 100%);
  border-color: var(--accent);
  transform: rotateY(180deg);
}

.fc-label {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--text-muted);
}
.fc-back .fc-label { color: var(--accent-dim); }

.fc-meta {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-secondary);
  display: flex; gap: 10px; flex-wrap: wrap;
}
.meta-tag {
  padding: 2px 8px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 999px;
}

.fc-text {
  font-size: 1.05rem;
  color: var(--text-primary);
  line-height: 1.6;
  flex: 1;
}
.fc-back .fc-text {
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--accent);
}

.fc-hint {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  color: var(--text-muted);
  text-align: center;
}

.fc-nav {
  display: flex;
  align-items: center;
  gap: 14px;
}
.fc-nav-btn { flex-shrink: 0; }
.fc-progress {
  flex: 1;
  height: 4px;
  background: var(--bg-elevated);
  border-radius: 2px;
  overflow: hidden;
}
.fc-progress-bar {
  height: 100%;
  background: var(--accent);
  border-radius: 2px;
  transition: width 0.3s ease;
}

.fc-footer {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-muted);
  text-align: center;
}


/* ═══════════════════════════════════
   QUIZ MODE
   ═══════════════════════════════════ */
.quiz-container {
  max-width: 680px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.quiz-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px;
}

.quiz-score-board {
  display: flex;
  align-items: center;
  gap: 12px;
  background: var(--bg-surface);
  border: 1px solid var(--border);
  padding: 10px 18px;
  border-radius: var(--radius-md);
}
.score-item { text-align: center; }
.score-num { font-family: var(--font-display); font-size: 1.6rem; font-weight: 700; line-height: 1; color: var(--accent); display:block; }
.score-lbl { font-family: var(--font-mono); font-size: 0.62rem; text-transform: uppercase; color: var(--text-muted); letter-spacing: 0.1em; }
.score-sep { font-size: 1.4rem; color: var(--text-muted); }
.score-pct {
  font-family: var(--font-mono);
  font-size: 1rem;
  font-weight: 500;
  color: var(--correct);
  min-width: 50px;
  text-align: center;
}

.quiz-controls { display: flex; gap: 8px; }

.quiz-progress-bar-wrap {
  height: 4px;
  background: var(--bg-elevated);
  border-radius: 2px;
  overflow: hidden;
}
.quiz-progress-bar {
  height: 100%;
  background: var(--accent);
  border-radius: 2px;
  transition: width 0.4s ease;
}

.quiz-card {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-md);
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.quiz-q-meta {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-secondary);
  display: flex; gap: 8px; flex-wrap: wrap;
}

.quiz-q-num {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-muted);
}

.quiz-question {
  font-size: 1.1rem;
  line-height: 1.65;
  color: var(--text-primary);
  font-weight: 400;
}

.quiz-input-area { display: flex; gap: 10px; }

.quiz-input {
  flex: 1;
  height: 44px;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  background: var(--bg-elevated);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 0.95rem;
  padding: 0 14px;
  outline: none;
  transition: border-color var(--transition);
}
.quiz-input:focus { border-color: var(--accent); box-shadow: 0 0 0 2px var(--accent-glow); }

.quiz-submit-btn {
  height: 44px;
  padding: 0 20px;
  border-radius: var(--radius-sm);
  border: none;
  background: var(--accent);
  color: var(--text-inverse);
  font-family: var(--font-body);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: background var(--transition), transform var(--transition);
}
.quiz-submit-btn:hover { background: var(--accent-dim); }
.quiz-submit-btn:active { transform: scale(0.97); }

.quiz-reveal {
  background: var(--bg-elevated);
  border-radius: var(--radius-md);
  padding: 18px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  animation: fadeIn 0.2s ease;
}
@keyframes fadeIn { from { opacity:0; transform:translateY(6px); } to { opacity:1; transform:translateY(0); } }

.quiz-reveal-label {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
}

.quiz-reveal-answer {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--accent);
}

.quiz-feedback {
  font-size: 0.9rem;
  font-weight: 500;
  padding: 6px 12px;
  border-radius: var(--radius-sm);
}
.quiz-feedback.correct { background: var(--correct-bg); color: var(--correct); }
.quiz-feedback.incorrect { background: var(--incorrect-bg); color: var(--incorrect); }

.quiz-next-btn {
  align-self: flex-start;
  padding: 8px 18px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-strong);
  background: var(--bg-surface);
  color: var(--text-secondary);
  font-family: var(--font-body);
  font-size: 0.85rem;
  cursor: pointer;
  transition: all var(--transition);
}
.quiz-next-btn:hover { border-color: var(--accent); color: var(--accent); }

.quiz-finished {
  text-align: center;
  padding: 50px 20px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 18px;
  animation: fadeIn 0.3s ease;
}
.finished-icon { font-size: 3rem; color: var(--accent); }
.quiz-finished h2 { font-family: var(--font-display); font-size: 1.8rem; }
.finished-score { font-family: var(--font-mono); font-size: 1.1rem; color: var(--text-secondary); }


/* ═══════════════════════════════════
   STATS MODE
   ═══════════════════════════════════ */
.stats-container { display: flex; flex-direction: column; gap: 24px; }

.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 14px;
}

.stat-card {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 24px;
  text-align: center;
  box-shadow: var(--shadow-sm);
  transition: border-color var(--transition), box-shadow var(--transition);
}
.stat-card:hover { border-color: var(--accent); box-shadow: 0 0 0 2px var(--accent-glow); }

.stat-num {
  font-family: var(--font-display);
  font-size: 2.4rem;
  font-weight: 700;
  color: var(--accent);
  line-height: 1;
}
.stat-lbl {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-secondary);
  margin-top: 6px;
}

.charts-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 18px;
}

.chart-card {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow: var(--shadow-sm);
}
.chart-card.chart-wide { grid-column: 1 / -1; }

.chart-title {
  font-family: var(--font-display);
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 18px;
}

.bar-chart { display: flex; flex-direction: column; gap: 8px; }

.bar-row {
  display: grid;
  grid-template-columns: 170px 1fr 44px;
  align-items: center;
  gap: 10px;
}

.bar-label {
  font-family: var(--font-body);
  font-size: 0.78rem;
  color: var(--text-secondary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.bar-track {
  height: 10px;
  background: var(--bg-elevated);
  border-radius: 5px;
  overflow: hidden;
}
.bar-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent-dim), var(--accent));
  border-radius: 5px;
  transition: width 0.6s cubic-bezier(0.4, 0, 0.2, 1);
  width: 0;
}

.bar-count {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-muted);
  text-align: right;
}


/* ═══════════════════════════════════
   LOADING OVERLAY
   ═══════════════════════════════════ */
.loading-overlay {
  position: fixed; inset: 0;
  background: var(--bg-base);
  z-index: 999;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 20px;
  transition: opacity 0.3s ease;
}
.loading-overlay.hidden { opacity: 0; pointer-events: none; }

.loading-spinner {
  width: 40px; height: 40px;
  border: 3px solid var(--border-strong);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

.loading-text {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-secondary);
  letter-spacing: 0.05em;
}


/* ═══════════════════════════════════
   TOAST
   ═══════════════════════════════════ */
.toast {
  position: fixed;
  bottom: 28px;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: var(--bg-elevated);
  border: 1px solid var(--border-strong);
  color: var(--text-primary);
  padding: 10px 22px;
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  opacity: 0;
  pointer-events: none;
  transition: all 0.25s ease;
  z-index: 9999;
  white-space: nowrap;
  box-shadow: var(--shadow-lg);
}
.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}


/* ═══════════════════════════════════
   RESPONSIVE
   ═══════════════════════════════════ */
@media (max-width: 768px) {
  .site-header { padding: 12px 16px; }
  .toolbar { padding: 8px 16px; }
  .filters-bar { padding: 12px 16px; }
  .main-content { padding: 16px; }
  .search-input { width: 180px; }
  .site-title { font-size: 1.1rem; }
  .fc-front, .fc-back { padding: 22px; }
  .quiz-card { padding: 22px; }
  .bar-row { grid-template-columns: 120px 1fr 36px; }

  .mode-tab span:not(.tab-icon) { display: none; }
  .mode-tab { padding: 7px 12px; }
}

@media (max-width: 480px) {
  .flashcard { height: 280px; }
  .stats-grid { grid-template-columns: 1fr 1fr; }
  .charts-row { grid-template-columns: 1fr; }
  .quiz-input-area { flex-direction: column; }
  .quiz-submit-btn { width: 100%; }
}