:root {
    --bg: #ffffff;
    --bg-soft: #f7f7f7;
    --bg-card: #ffffff;
    --bg-hover: #fafafa;
    --bg-elev: #ffffff;
    --text: #0a0a0a;
    --text-2: #404040;
    --text-3: #737373;
    --text-4: #a3a3a3;
    --line: #ededed;
    --line-2: #d4d4d4;
    --known: #16a34a;
    --known-bg: #dcfce7;
    --hard: #ea580c;
    --hard-bg: #ffedd5;
    --correct: #16a34a;
    --wrong: #dc2626;
    --accent: #0a0a0a;
  }

  [data-theme="dark"] {
    --bg: #0a0a0a;
    --bg-soft: #141414;
    --bg-card: #141414;
    --bg-hover: #1a1a1a;
    --bg-elev: #161616;
    --text: #fafafa;
    --text-2: #d4d4d4;
    --text-3: #a3a3a3;
    --text-4: #737373;
    --line: #1f1f1f;
    --line-2: #2e2e2e;
    --known: #4ade80;
    --known-bg: rgba(74, 222, 128, 0.1);
    --hard: #fb923c;
    --hard-bg: rgba(251, 146, 60, 0.1);
    --correct: #4ade80;
    --wrong: #f87171;
    --accent: #fafafa;
  }

  html.no-theme-motion *,
  html.no-theme-motion *::before,
  html.no-theme-motion *::after {
    transition: none !important;
    animation: none !important;
  }

  * { box-sizing: border-box; margin: 0; padding: 0; }
  html {
    scroll-behavior: smooth;
    touch-action: manipulation;
  }

  body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
    min-height: 100vh;
    transition: none;
    touch-action: manipulation;
  }

  ::selection { background: var(--text); color: var(--bg); }

  button, a, input, select, textarea {
    font-family: inherit;
    touch-action: manipulation;
  }

  /* ============== GLOBAL ANIMATIONS ============== */
  @keyframes fadeInUp {
    from { opacity: 0; transform: translateY(14px); }
    to { opacity: 1; transform: translateY(0); }
  }

  @keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
  }

  @keyframes slideInLeft {
    from { opacity: 0; transform: translateX(-12px); }
    to { opacity: 1; transform: translateX(0); }
  }

  @keyframes pop {
    0% { transform: scale(1); }
    40% { transform: scale(1.18); }
    100% { transform: scale(1); }
  }

  @keyframes shake {
    0%, 100% { transform: translateX(0); }
    15%, 55% { transform: translateX(-7px); }
    35%, 75% { transform: translateX(7px); }
  }

  @keyframes flipReveal {
    0% { transform: rotateY(0); opacity: 1; }
    49% { transform: rotateY(90deg); opacity: 0; }
    50% { transform: rotateY(-90deg); opacity: 0; }
    100% { transform: rotateY(0); opacity: 1; }
  }

  @keyframes celebrate {
    0% { transform: scale(1); }
    40% { transform: scale(1.2); }
    70% { transform: scale(0.94); }
    100% { transform: scale(1); }
  }

  /* Note: animations always run, regardless of prefers-reduced-motion.
     If you experience motion sensitivity, the system reduce-motion is intentionally not respected here. */

  /* ============== TOP NAV ============== */
  .topnav {
    border-bottom: 1px solid var(--line);
    position: sticky;
    top: 0;
    z-index: 100;
    background: var(--bg);
    transition: box-shadow 0.2s, background 0.2s;
  }
  .topnav.scrolled {
    box-shadow: 0 1px 0 var(--line), 0 4px 12px rgba(0,0,0,0.04);
  }
  [data-theme="dark"] .topnav.scrolled {
    box-shadow: 0 1px 0 var(--line), 0 4px 16px rgba(0,0,0,0.4);
  }

  .topnav-inner {
    width: 100%;
    max-width: none;
    margin: 0 auto;
    padding: 14px 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 16px;
  }

  .topnav-left {
    display: flex;
    align-items: center;
    gap: 8px;
    min-width: 0;
  }

  .brand {
    font-weight: 600;
    font-size: 15px;
    letter-spacing: -0.015em;
    color: var(--text);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 10px;
    min-width: 0;
  }

  .brand span:last-child {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }

  .brand-mark {
    width: 22px; height: 22px;
    background: var(--text);
    color: var(--bg);
    border-radius: 5px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 12px;
    font-weight: 700;
    transition: transform 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
  }

  .brand:hover .brand-mark {
    transform: rotate(-8deg) scale(1.08);
  }

  .topnav-actions { display: flex; gap: 6px; align-items: center; }

  .nav-back {
    height: 36px;
    padding: 0 11px;
    border-radius: 8px;
    border: 1px solid var(--line);
    display: inline-flex;
    align-items: center;
    gap: 6px;
    color: var(--text-2);
    text-decoration: none;
    font-size: 13px;
    font-weight: 700;
    transition: background 0.16s, border-color 0.16s, color 0.16s;
  }

  .nav-back:hover {
    background: var(--bg-hover);
    border-color: var(--line-2);
    color: var(--text);
  }

  .demo-access-link {
    height: 36px;
    padding: 0 12px;
    border-radius: 8px;
    border: 1px solid var(--line);
    display: inline-flex;
    align-items: center;
    color: var(--text);
    text-decoration: none;
    font-size: 13px;
    font-weight: 700;
    transition: background 0.2s, border-color 0.2s;
  }

  .demo-access-link:hover {
    background: var(--bg-hover);
    border-color: var(--line-2);
  }

  .icon-btn {
    background: transparent;
    border: 1px solid var(--line);
    color: var(--text-2);
    width: 36px; height: 36px;
    border-radius: 8px;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    transition: all 0.18s cubic-bezier(0.4, 0, 0.2, 1);
  }
  .icon-btn:hover {
    border-color: var(--text-3);
    color: var(--text);
    transform: translateY(-1px);
  }
  .icon-btn:active {
    transform: translateY(0);
  }
  .icon-btn svg {
    transition: transform 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
  }
  #reset-progress:hover svg {
    transform: rotate(-180deg);
  }
  #theme-toggle:hover svg {
    transform: rotate(45deg);
  }

  /* ============== HEADER ============== */
  .hero {
    padding: 56px 24px 40px;
    border-bottom: 1px solid var(--line);
  }

  .hero-inner { max-width: 920px; margin: 0 auto; }

  .demo-banner {
    margin: 0 0 28px;
    padding: 14px 16px;
    border: 1px solid var(--line);
    border-radius: 12px;
    background: var(--bg-card);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    box-shadow: 0 10px 28px rgba(0,0,0,0.04);
    animation: fadeInUp 0.45s ease both;
  }

  .demo-banner strong {
    display: block;
    font-size: 14px;
    margin-bottom: 2px;
  }

  .demo-banner span {
    color: var(--text-3);
    font-size: 13px;
  }

  .demo-banner a {
    flex: 0 0 auto;
    color: var(--text);
    font-size: 13px;
    font-weight: 800;
    text-decoration: none;
    border-bottom: 1px solid currentColor;
  }

  .eyebrow {
    font-family: 'JetBrains Mono', monospace;
    font-size: 12px;
    color: var(--text-3);
    margin-bottom: 20px;
    animation: fadeInUp 0.5s ease 0.05s both;
  }

  h1.title {
    font-weight: 700;
    font-size: clamp(34px, 5vw, 48px);
    line-height: 1.05;
    letter-spacing: -0.03em;
    color: var(--text);
    margin-bottom: 14px;
    max-width: 720px;
    animation: fadeInUp 0.6s ease 0.1s both;
  }

  .subtitle {
    font-size: clamp(15px, 1.5vw, 17px);
    color: var(--text-3);
    max-width: 580px;
    line-height: 1.55;
    margin-bottom: 36px;
    animation: fadeInUp 0.6s ease 0.18s both;
  }

  /* ============== STATS — now meaningful ============== */
  .stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: 0;
    border-top: 1px solid var(--line);
    padding-top: 24px;
    animation: fadeInUp 0.6s ease 0.25s both;
  }

  .stat {
    padding-right: 24px;
  }

  .stat-value {
    font-size: 26px;
    font-weight: 600;
    line-height: 1;
    letter-spacing: -0.025em;
    color: var(--text);
    margin-bottom: 6px;
    font-feature-settings: "tnum";
    transition: color 0.3s ease;
  }

  .stat-value.known { color: var(--known); }
  .stat-value.hard { color: var(--hard); }

  .stat-value.bumping { animation: none; }

  .stat-label {
    font-size: 12px;
    color: var(--text-3);
  }

  /* Progress bar in stats */
  .progress-wrap {
    margin-top: 16px;
    padding-top: 16px;
    border-top: 1px solid var(--line);
    animation: fadeInUp 0.6s ease 0.32s both;
  }
  .progress-bar {
    height: 6px;
    background: var(--bg-soft);
    border-radius: 3px;
    overflow: hidden;
    display: flex;
    position: relative;
  }
  .progress-bar .seg-known {
    background: var(--known);
    height: 100%;
    transition: width 0.6s cubic-bezier(0.4, 0, 0.2, 1);
  }
  .progress-bar .seg-hard {
    background: var(--hard);
    height: 100%;
    transition: width 0.6s cubic-bezier(0.4, 0, 0.2, 1);
  }
  .progress-label {
    margin-top: 8px;
    font-size: 12px;
    color: var(--text-3);
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
  }
  .progress-label .legend {
    display: inline-flex;
    align-items: center;
    gap: 6px;
  }
  .progress-label .dot {
    width: 8px; height: 8px;
    border-radius: 50%;
    display: inline-block;
  }
  .dot.known { background: var(--known); }
  .dot.hard { background: var(--hard); }

  .source-file-card {
    margin-top: 18px;
    padding: 14px 16px;
    border: 1px solid var(--line);
    border-radius: 14px;
    background:
      linear-gradient(135deg, rgba(59,130,246,0.08), transparent 48%),
      var(--bg-card);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    animation: fadeInUp 0.6s ease 0.38s both;
  }

  .source-file-card strong {
    display: block;
    font-size: 14px;
    margin-bottom: 3px;
  }

  .source-file-card span {
    display: block;
    color: var(--text-3);
    font-size: 13px;
    line-height: 1.45;
  }

  .source-file-actions {
    display: flex;
    flex-wrap: wrap;
    justify-content: flex-end;
    gap: 8px;
    flex: 0 0 auto;
  }

  .source-file-actions a {
    min-height: 34px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 7px 12px;
    border-radius: 999px;
    border: 1px solid var(--line-2);
    background: var(--bg-elev);
    color: var(--text);
    text-decoration: none;
    font-size: 13px;
    font-weight: 800;
    transition: border-color 0.15s ease, transform 0.15s ease;
  }

  .source-file-actions a:hover,
  .source-file-actions a:focus-visible {
    border-color: var(--text-3);
    transform: translateY(-1px);
    outline: none;
  }

  /* ============== CONTROLS ============== */
  .controls {
    border-bottom: 1px solid var(--line);
    position: relative;
    top: auto;
    z-index: 1;
    background: var(--bg);
  }

  .controls-inner {
    max-width: 920px;
    margin: 0 auto;
    padding: 14px 24px;
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    align-items: center;
  }

  .search-box {
    flex: 1 1 240px;
    position: relative;
  }

  .search-box input {
    width: 100%;
    padding: 11px 14px 11px 40px;
    background: var(--bg-soft);
    border: 1px solid transparent;
    border-radius: 10px;
    font-family: inherit;
    font-size: 14px;
    color: var(--text);
    transition: all 0.15s;
  }

  .search-box input::placeholder { color: var(--text-4); }

  .search-box input:focus {
    outline: none;
    border-color: var(--text);
    background: var(--bg);
  }

  .search-box svg {
    position: absolute;
    left: 13px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-3);
    pointer-events: none;
  }

  .clear-btn {
    position: absolute;
    right: 8px;
    top: 50%;
    transform: translateY(-50%);
    background: transparent;
    border: none;
    width: 26px; height: 26px;
    border-radius: 6px;
    color: var(--text-3);
    cursor: pointer;
    display: none;
    align-items: center; justify-content: center;
  }
  .clear-btn:hover { background: var(--bg-hover); color: var(--text); }
  .clear-btn.show { display: flex; }

  .filter-group, .mode-toggle {
    display: flex;
    background: var(--bg-soft);
    border-radius: 10px;
    padding: 3px;
  }

  .filter-btn, .mode-btn {
    background: transparent;
    border: none;
    padding: 8px 13px;
    border-radius: 7px;
    font-size: 13px;
    font-weight: 500;
    color: var(--text-3);
    cursor: pointer;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    white-space: nowrap;
    position: relative;
  }

  .filter-btn:hover, .mode-btn:hover {
    color: var(--text);
    transform: translateY(-1px);
  }
  .filter-btn:active, .mode-btn:active {
    transform: translateY(0);
  }

  .filter-btn.active, .mode-btn.active {
    background: var(--bg);
    color: var(--text);
    font-weight: 600;
    box-shadow: 0 1px 2px rgba(0,0,0,0.04);
    transform: none;
  }

  [data-theme="dark"] .filter-btn.active,
  [data-theme="dark"] .mode-btn.active {
    background: var(--text);
    color: var(--bg);
    box-shadow: none;
  }

  /* Status filter chips (extra row) */
  .status-row {
    max-width: 920px;
    margin: 0 auto;
    padding: 0 24px 14px;
    display: flex;
    gap: 6px;
    align-items: center;
    flex-wrap: wrap;
  }

  .status-row .label {
    font-size: 12px;
    color: var(--text-3);
    margin-right: 4px;
  }

  .chip {
    background: transparent;
    border: 1px solid var(--line);
    color: var(--text-2);
    padding: 5px 11px;
    border-radius: 999px;
    font-size: 12px;
    font-weight: 500;
    cursor: pointer;
    transition: background 0.15s ease, border-color 0.15s ease, color 0.15s ease;
    display: inline-flex;
    align-items: center;
    gap: 6px;
  }

  .chip:hover {
    border-color: var(--text-3);
    color: var(--text);
    transform: translateY(-1px);
  }

  .chip.active {
    background: var(--text);
    color: var(--bg);
    border-color: var(--text);
    transform: none;
  }

  .chip .count {
    font-family: 'JetBrains Mono', monospace;
    font-size: 11px;
    opacity: 0.7;
  }

  /* ============== MAIN ============== */
  .container {
    max-width: 920px;
    margin: 0 auto;
    padding: 32px 24px 80px;
  }

  /* ============== CATEGORY / SUBTOPIC ============== */
  .category {
    margin-bottom: 56px;
    scroll-margin-top: 130px;
  }

  .category-header { margin-bottom: 24px; }

  .category-eyebrow {
    font-family: 'JetBrains Mono', monospace;
    font-size: 11px;
    color: var(--text-3);
    margin-bottom: 8px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
  }

  .category-title-block {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: 16px;
    flex-wrap: wrap;
  }

  .category-titles h2 {
    font-weight: 700;
    font-size: clamp(22px, 2.8vw, 28px);
    line-height: 1.1;
    letter-spacing: -0.025em;
    color: var(--text);
  }

  .category-meta {
    font-size: 13px;
    color: var(--text-3);
    margin-top: 6px;
  }
  .category-meta .dk-name {
    font-family: 'JetBrains Mono', monospace;
    font-size: 12px;
  }

  .category-count {
    font-size: 12px;
    color: var(--text-3);
    font-weight: 500;
    font-family: 'JetBrains Mono', monospace;
    flex-shrink: 0;
  }

  /* Subtopic block */
  .subtopic {
    margin-bottom: 32px;
    position: relative;
    animation: fadeInUp 0.5s ease both;
  }

  .subtopic-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    padding: 14px 16px;
    background: var(--bg-soft);
    border-radius: 10px;
    margin-bottom: 4px;
    cursor: pointer;
    user-select: none;
    transition: background 0.2s ease, transform 0.15s ease;
    position: relative;
    top: auto;
    z-index: 1;
  }

  .subtopic-header:hover {
    background: var(--bg-hover);
  }
  .subtopic-header:active {
    transform: scale(0.99);
  }

  .subtopic-title {
    font-size: 14px;
    font-weight: 600;
    color: var(--text);
    letter-spacing: -0.005em;
    display: flex;
    align-items: center;
    gap: 10px;
    transition: color 0.15s;
    flex: 1;
    min-width: 0;
  }

  .subtopic-title .toggle {
    color: var(--text-3);
    font-size: 10px;
    transition: transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
    flex-shrink: 0;
    width: 12px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
  }

  .subtopic.collapsed .toggle {
    transform: rotate(-90deg);
  }

  .subtopic .items {
    overflow: hidden;
    transition: max-height 0.4s cubic-bezier(0.4, 0, 0.2, 1);
  }

  .subtopic.collapsed .items {
    max-height: 0 !important;
    margin-bottom: 0;
  }

  .subtopic-ru {
    font-size: 12px;
    color: var(--text-3);
    font-weight: 400;
    margin-left: 4px;
  }

  .subtopic-count {
    font-family: 'JetBrains Mono', monospace;
    font-size: 11px;
    color: var(--text-3);
    background: var(--bg);
    padding: 3px 8px;
    border-radius: 5px;
    flex-shrink: 0;
  }

  /* ============== ITEMS ============== */
  /* Hierarchy: EN (primary, big) > RU (secondary, medium) > DK (tertiary, small grey) */
  .items {
    display: flex;
    flex-direction: column;
    padding: 0 4px;
  }

  .item {
    padding: 16px 12px;
    border-bottom: 1px solid var(--line);
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 16px;
    align-items: start;
    transition: background 0.2s ease, opacity 0.25s ease, transform 0.2s ease, padding-left 0.2s ease;
    border-radius: 8px;
    animation: fadeIn 0.4s ease both;
  }

  .item:hover {
    background: var(--bg-hover);
    padding-left: 16px;
  }

  .item:last-child { border-bottom: none; }

  .item.is-known { opacity: 0.86; }
  .item.is-known:hover { opacity: 1; }
  .item.is-hard {
    background: linear-gradient(90deg, rgba(234,88,12,0.05), transparent 42%);
  }
  .item.is-untouched .item-en {
    color: var(--text);
  }

  .item-content { min-width: 0; }

  .item-en-row {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 4px;
    flex-wrap: wrap;
  }

  .item-en {
    font-weight: 600;
    font-size: 18px;
    color: var(--text);
    line-height: 1.3;
    letter-spacing: -0.015em;
    flex: 1;
    min-width: 0;
  }

  /* RU is your second main language — make it readable, but lighter than EN */
  .item-ru {
    font-size: 15px;
    color: var(--text-2);
    line-height: 1.4;
    margin-bottom: 6px;
  }

  /* DK is reference only — small, muted, italic */
  .item-dk {
    font-family: 'JetBrains Mono', monospace;
    font-size: 12px;
    color: var(--text-4);
    font-style: italic;
    line-height: 1.3;
    display: inline-flex;
    align-items: center;
    gap: 6px;
  }

  /* Inline speak button — always visible, properly tappable on mobile */
  .speak-inline {
    background: var(--bg-soft);
    border: 1px solid var(--line);
    color: var(--text-2);
    cursor: pointer;
    padding: 6px;
    border-radius: 8px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    transition: background 0.15s ease, border-color 0.15s ease, color 0.15s ease;
    line-height: 0;
    flex-shrink: 0;
    width: 32px;
    height: 32px;
  }
  .speak-inline:hover {
    color: var(--text);
    background: var(--bg-hover);
    border-color: var(--text-3);
  }
  .speak-inline:active {
    transform: none;
  }
  .speak-inline.speaking {
    color: var(--known);
    border-color: var(--known);
    background: var(--known-bg);
    animation: pulse 0.8s ease infinite;
  }

  /* Status badge inline with English */
  .badge {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    font-size: 10px;
    font-weight: 600;
    padding: 2px 8px;
    border-radius: 999px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-family: 'JetBrains Mono', monospace;
    animation: fadeIn 0.3s ease both;
  }

  .badge.known { background: var(--known-bg); color: var(--known); }
  .badge.hard { background: var(--hard-bg); color: var(--hard); }
  .badge.cat {
    background: transparent;
    color: var(--text-3);
    border: 1px solid var(--line-2);
    font-weight: 500;
  }

  /* Item actions (mark) */
  .item-actions {
    display: flex;
    gap: 4px;
    align-items: center;
    flex-shrink: 0;
    padding-top: 2px;
  }

  .action-btn {
    background: transparent;
    border: 1px solid transparent;
    color: var(--text-4);
    width: 32px; height: 32px;
    border-radius: 8px;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    transition: all 0.18s cubic-bezier(0.4, 0, 0.2, 1);
    font-size: 16px;
  }

  .action-btn:hover {
    color: var(--text);
    background: var(--bg-soft);
  }

  .action-btn:active {
    transform: none;
  }

  .action-btn.active.known {
    color: var(--known);
    background: var(--known-bg);
  }
  .action-btn.active.hard {
    color: var(--hard);
    background: var(--hard-bg);
  }
  .action-btn.active.unknown {
    color: var(--text-3);
    background: var(--bg-soft);
    border-color: var(--line-2);
  }

  .action-btn.just-marked {
    animation: none;
  }

  .action-btn.speaking {
    color: var(--text);
    animation: pulse 0.8s ease infinite;
  }

  @keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.4; }
  }

  /* highlight on search */
  mark {
    background: var(--text);
    color: var(--bg);
    padding: 0 3px;
    border-radius: 2px;
    font-weight: 500;
  }

  /* ============== QUICK NAV ============== */
  .quick-nav {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
    margin: 0 0 32px;
    padding-bottom: 24px;
    border-bottom: 1px solid var(--line);
  }

  .nav-pill {
    background: transparent;
    border: 1px solid var(--line);
    color: var(--text-2);
    padding: 8px 14px;
    border-radius: 8px;
    text-decoration: none;
    font-size: 13px;
    font-weight: 500;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    display: inline-flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
  }

  .nav-pill:hover {
    border-color: var(--text);
    color: var(--text);
    background: var(--bg-soft);
    transform: translateY(-1px);
  }
  .nav-pill:active {
    transform: translateY(0);
  }

  .nav-pill .count {
    color: var(--text-4);
    font-size: 11px;
    font-family: 'JetBrains Mono', monospace;
  }

  /* ============== FLASHCARDS ============== */
  .flashcard-view, .quiz-view { display: none; }
  body.mode-list .list-view { display: block; animation: fadeIn 0.3s ease; }
  body.mode-flash .flashcard-view { display: block; animation: fadeInUp 0.4s ease; }
  body.mode-quiz .quiz-view { display: block; animation: fadeInUp 0.4s ease; }
  body:not(.mode-list) .list-view { display: none; }

  .flashcard-stage, .quiz-stage {
    max-width: 640px;
    margin: 32px auto;
  }

  .flash-progress, .quiz-progress {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 12px;
    color: var(--text-3);
    margin-bottom: 12px;
    font-family: 'JetBrains Mono', monospace;
  }

  .flash-progress .num, .quiz-progress .num { color: var(--text); font-weight: 600; }

  .flash-bar, .quiz-bar {
    height: 2px;
    background: var(--line);
    border-radius: 2px;
    overflow: hidden;
    margin-bottom: 28px;
  }

  .flash-bar-fill, .quiz-bar-fill {
    height: 100%;
    background: var(--text);
    transition: width 0.3s;
  }

  .flashcard {
    background: var(--bg);
    border: 1px solid var(--line);
    border-radius: 16px;
    padding: 64px 40px;
    min-height: 340px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    cursor: pointer;
    user-select: none;
    transition: border-color 0.2s ease, box-shadow 0.3s ease, transform 0.2s ease;
    position: relative;
    text-align: center;
    transform-style: preserve-3d;
    will-change: transform;
  }

  .flashcard:hover {
    border-color: var(--text-3);
    box-shadow: 0 4px 20px rgba(0,0,0,0.04);
    transform: translateY(-2px);
  }
  [data-theme="dark"] .flashcard:hover {
    box-shadow: 0 4px 24px rgba(0,0,0,0.4);
  }

  .flashcard.flipping {
    animation: flipReveal 0.5s cubic-bezier(0.4, 0, 0.2, 1);
  }

  .flash-side-label {
    position: absolute;
    top: 18px; right: 20px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 10px;
    color: var(--text-4);
    letter-spacing: 0.1em;
    text-transform: uppercase;
    transition: color 0.3s ease;
  }
  .flashcard.flipped .flash-side-label { color: var(--text-3); }

  .flash-actions {
    position: absolute;
    top: 14px; left: 14px;
    display: flex;
    gap: 4px;
  }

  .flash-lang {
    font-family: 'JetBrains Mono', monospace;
    font-size: 11px;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    color: var(--text-3);
    margin-bottom: 18px;
  }

  .flash-word {
    font-weight: 700;
    font-size: clamp(28px, 5vw, 42px);
    line-height: 1.1;
    letter-spacing: -0.03em;
    color: var(--text);
  }

  /* Smooth back/front fade instead of hard switch */
  .flash-front, .flash-back {
    transition: opacity 0.2s ease;
  }
  .flash-back { display: none; }
  .flashcard.flipped .flash-front { display: none; }
  .flashcard.flipped .flash-back { display: block; }

  .flash-back .flash-dk-text {
    font-family: 'JetBrains Mono', monospace;
    font-size: 18px;
    color: var(--text-3);
    margin-bottom: 14px;
    font-style: italic;
    display: inline-flex;
    align-items: center;
    gap: 8px;
  }

  .flash-back .flash-ru-text {
    font-size: 22px;
    color: var(--text);
    line-height: 1.3;
    font-weight: 500;
    letter-spacing: -0.015em;
  }

  .flash-hint {
    position: absolute;
    bottom: 16px; left: 0; right: 0;
    font-size: 11px;
    color: var(--text-4);
    font-family: 'JetBrains Mono', monospace;
    padding: 0 16px;
  }

  .flash-controls {
    display: flex;
    gap: 8px;
    justify-content: center;
    margin-top: 24px;
    flex-wrap: wrap;
  }

  .flash-btn {
    background: var(--bg);
    border: 1px solid var(--line-2);
    color: var(--text);
    padding: 11px 20px;
    border-radius: 10px;
    font-family: inherit;
    font-weight: 500;
    font-size: 13px;
    cursor: pointer;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  }

  .flash-btn:hover {
    background: var(--bg-soft);
    transform: translateY(-1px);
  }
  .flash-btn:active {
    transform: translateY(0);
  }

  .flash-btn.primary {
    background: var(--text);
    color: var(--bg);
    border-color: var(--text);
    font-weight: 600;
    padding: 11px 28px;
  }
  .flash-btn.primary:hover {
    opacity: 0.85;
    transform: translateY(-1px);
  }
  .flash-btn:disabled {
    opacity: 0.3;
    cursor: not-allowed;
    transform: none !important;
  }

  /* ============== QUIZ ============== */
  .quiz-card {
    background: var(--bg);
    border: 1px solid var(--line);
    border-radius: 16px;
    padding: 36px 32px;
  }

  .quiz-question-label {
    font-family: 'JetBrains Mono', monospace;
    font-size: 11px;
    color: var(--text-3);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: 16px;
    display: flex;
    align-items: center;
    gap: 8px;
  }

  .quiz-question {
    font-size: clamp(24px, 4vw, 30px);
    font-weight: 700;
    line-height: 1.2;
    letter-spacing: -0.025em;
    color: var(--text);
    margin-bottom: 28px;
    display: flex;
    align-items: center;
    gap: 10px;
    flex-wrap: wrap;
  }

  .quiz-options {
    display: flex;
    flex-direction: column;
    gap: 10px;
  }

  .quiz-option {
    background: var(--bg);
    border: 1.5px solid var(--line);
    color: var(--text);
    padding: 14px 18px;
    border-radius: 10px;
    text-align: left;
    cursor: pointer;
    font-size: 15px;
    font-weight: 500;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    display: flex;
    align-items: center;
    gap: 12px;
    animation: fadeInUp 0.3s ease both;
  }

  .quiz-option:nth-child(1) { animation-delay: 0.05s; }
  .quiz-option:nth-child(2) { animation-delay: 0.1s; }
  .quiz-option:nth-child(3) { animation-delay: 0.15s; }
  .quiz-option:nth-child(4) { animation-delay: 0.2s; }

  .quiz-option:hover:not(:disabled) {
    border-color: var(--text-3);
    background: var(--bg-soft);
    transform: translateX(3px);
  }

  .quiz-option:active:not(:disabled) {
    transform: scale(0.99);
  }

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

  .quiz-option .key {
    font-family: 'JetBrains Mono', monospace;
    font-size: 11px;
    color: var(--text-4);
    background: var(--bg-soft);
    border: 1px solid var(--line);
    padding: 2px 6px;
    border-radius: 4px;
    flex-shrink: 0;
    transition: all 0.2s;
  }

  .quiz-option.correct {
    border-color: var(--correct);
    background: var(--known-bg);
    color: var(--correct);
    animation: celebrate 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
  }
  .quiz-option.correct .key { background: var(--correct); color: white; border-color: var(--correct); }

  .quiz-option.wrong {
    border-color: var(--wrong);
    background: color-mix(in srgb, var(--wrong) 8%, transparent);
    color: var(--wrong);
    animation: shake 0.4s ease;
  }
  .quiz-option.wrong .key { background: var(--wrong); color: white; border-color: var(--wrong); }

  .quiz-feedback {
    margin-top: 20px;
    padding: 14px 16px;
    border-radius: 10px;
    background: var(--bg-soft);
    display: none;
    font-size: 14px;
  }
  .quiz-feedback.show {
    display: block;
    animation: fadeInUp 0.3s ease both;
  }
  .quiz-feedback .correct-answer {
    font-weight: 600;
    color: var(--text);
  }
  .quiz-feedback .ru-text {
    color: var(--text-3);
    font-size: 13px;
    margin-top: 4px;
  }

  .quiz-controls {
    display: flex;
    gap: 8px;
    justify-content: space-between;
    margin-top: 20px;
    flex-wrap: wrap;
  }

  .quiz-score {
    background: var(--bg-soft);
    border: 1px solid var(--line);
    border-radius: 10px;
    padding: 20px;
    margin-bottom: 20px;
    display: flex;
    justify-content: space-around;
    text-align: center;
    flex-wrap: wrap;
    gap: 16px;
  }

  .quiz-score-item .val {
    font-size: 24px;
    font-weight: 700;
    line-height: 1;
    margin-bottom: 4px;
    font-feature-settings: "tnum";
  }
  .quiz-score-item .lbl {
    font-size: 11px;
    color: var(--text-3);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-family: 'JetBrains Mono', monospace;
  }
  .quiz-score-item .val.correct { color: var(--correct); }
  .quiz-score-item .val.wrong { color: var(--wrong); }

  .quiz-empty {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-3);
  }
  .quiz-empty .big {
    font-size: 22px;
    color: var(--text);
    margin-bottom: 8px;
    font-weight: 600;
  }

  .quiz-direction-toggle {
    display: flex;
    gap: 0;
    background: var(--bg-soft);
    border-radius: 8px;
    padding: 3px;
    margin-bottom: 20px;
  }

  .quiz-direction-toggle button {
    background: transparent;
    border: none;
    padding: 8px 14px;
    border-radius: 6px;
    font-size: 12px;
    font-weight: 500;
    color: var(--text-3);
    cursor: pointer;
    flex: 1;
    transition: all 0.15s;
  }
  .quiz-direction-toggle button:hover { color: var(--text); }
  .quiz-direction-toggle button.active {
    background: var(--bg);
    color: var(--text);
    font-weight: 600;
    box-shadow: 0 1px 2px rgba(0,0,0,0.04);
  }
  [data-theme="dark"] .quiz-direction-toggle button.active {
    background: var(--text);
    color: var(--bg);
    box-shadow: none;
  }

  /* ============== EMPTY ============== */
  .empty {
    text-align: center;
    padding: 100px 20px;
    color: var(--text-3);
  }
  .empty .big {
    font-size: 22px;
    color: var(--text);
    margin-bottom: 8px;
    font-weight: 600;
    letter-spacing: -0.015em;
  }

  /* ============== TTS BANNER ============== */
  .tts-banner {
    max-width: 920px;
    margin: 0 auto;
    padding: 10px 24px;
    display: none;
    align-items: center;
    gap: 10px;
    font-size: 13px;
    color: var(--text-2);
    border-bottom: 1px solid var(--line);
  }
  .tts-banner.info { background: var(--bg-soft); }
  .tts-banner.warn { background: var(--hard-bg); color: var(--hard); }
  .tts-banner a { color: inherit; text-decoration: underline; }

  /* ============== TTS DIALOG ============== */
  .tts-dialog {
    position: fixed;
    inset: 0;
    z-index: 200;
    display: none;
    align-items: center;
    justify-content: center;
    padding: 20px;
  }
  .tts-dialog.open {
    display: flex;
    animation: fadeIn 0.2s ease;
  }

  .tts-dialog-backdrop {
    position: absolute;
    inset: 0;
    background: rgba(0,0,0,0.5);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
  }
  [data-theme="dark"] .tts-dialog-backdrop { background: rgba(0,0,0,0.7); }

  .tts-dialog-panel {
    position: relative;
    background: var(--bg);
    border: 1px solid var(--line);
    border-radius: 16px;
    width: 100%;
    max-width: 560px;
    max-height: 80vh;
    display: flex;
    flex-direction: column;
    box-shadow: 0 25px 80px rgba(0,0,0,0.25);
    animation: fadeInUp 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
  }

  .tts-dialog-header {
    padding: 20px 24px 14px;
    border-bottom: 1px solid var(--line);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
  }
  .tts-dialog-title {
    font-size: 17px;
    font-weight: 700;
    letter-spacing: -0.015em;
  }
  .tts-dialog-close {
    background: transparent;
    border: none;
    color: var(--text-3);
    width: 32px; height: 32px;
    border-radius: 8px;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    transition: all 0.15s;
  }
  .tts-dialog-close:hover { background: var(--bg-soft); color: var(--text); }

  .tts-status {
    padding: 14px 24px;
    font-size: 13px;
    color: var(--text-2);
    background: var(--bg-soft);
    border-bottom: 1px solid var(--line);
  }
  .tts-status .good { color: var(--known); font-weight: 700; margin-right: 4px; }
  .tts-status .warn { color: var(--hard); font-weight: 700; margin-right: 4px; }
  .tts-status .bad { color: var(--wrong); font-weight: 700; margin-right: 4px; }

  .tts-voice-list {
    overflow-y: auto;
    padding: 8px 16px 16px;
    flex: 1;
  }

  .tts-section-title {
    font-family: 'JetBrains Mono', monospace;
    font-size: 11px;
    color: var(--text-3);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    padding: 14px 8px 8px;
    font-weight: 600;
  }

  .tts-voice {
    width: 100%;
    background: var(--bg);
    border: 1px solid var(--line);
    border-radius: 10px;
    padding: 12px 14px;
    margin-bottom: 6px;
    cursor: pointer;
    text-align: left;
    transition: all 0.18s cubic-bezier(0.4, 0, 0.2, 1);
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 12px;
    align-items: center;
    position: relative;
  }
  .tts-voice:hover {
    border-color: var(--text-3);
    background: var(--bg-hover);
    transform: translateX(3px);
  }
  .tts-voice.selected {
    border-color: var(--text);
    background: var(--bg-soft);
  }
  .tts-voice-name {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
  }
  .tts-name {
    font-weight: 600;
    font-size: 14px;
    color: var(--text);
  }
  .tts-current {
    font-family: 'JetBrains Mono', monospace;
    font-size: 10px;
    color: var(--known);
    background: var(--known-bg);
    padding: 2px 6px;
    border-radius: 4px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
  }
  .tts-voice-meta {
    grid-column: 1;
    font-size: 12px;
    color: var(--text-3);
    font-family: 'JetBrains Mono', monospace;
    margin-top: 4px;
  }
  .tts-voice-test {
    grid-row: 1 / 3;
    grid-column: 2;
    background: transparent;
    border: 1px solid var(--line);
    color: var(--text-2);
    width: 36px; height: 36px;
    border-radius: 8px;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    transition: all 0.15s;
  }
  .tts-voice-test:hover {
    background: var(--text);
    color: var(--bg);
    border-color: var(--text);
    transform: scale(1.08);
  }
  .tts-voice-test.speaking {
    background: var(--known);
    color: white;
    border-color: var(--known);
    animation: pulse 0.8s ease infinite;
  }

  .tts-empty {
    text-align: center;
    padding: 20px;
    color: var(--text-3);
    font-size: 13px;
  }

  .tts-dialog-footer {
    padding: 14px 24px;
    border-top: 1px solid var(--line);
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 12px;
    font-size: 12px;
    color: var(--text-3);
    flex-wrap: wrap;
  }
  .tts-dialog-footer a {
    color: var(--text);
    text-decoration: underline;
    cursor: pointer;
  }

  /* ============== FOOTER ============== */
  footer {
    border-top: 1px solid var(--line);
    padding: 24px;
    text-align: center;
    color: var(--text-3);
    font-size: 13px;
  }

  footer .copyright { font-family: 'JetBrains Mono', monospace; font-size: 12px; }

  /* ============== RESPONSIVE ============== */
  @media (max-width: 640px) {
    .hero { padding: 36px 20px 28px; }
    .controls {
      position: static;
      top: auto;
      z-index: auto;
    }
    .controls-inner { padding: 12px 16px; }
    .container { padding: 28px 20px 60px; }
    .subtopic-header {
      position: relative;
      top: auto;
      z-index: 1;
    }
    .topnav-inner { padding: 12px 16px; }
    .topnav-left { gap: 6px; }
    .nav-back { width: 34px; padding: 0; justify-content: center; }
    .nav-back span { display: none; }
    .brand { font-size: 14px; gap: 8px; }
    .brand-mark { width: 21px; height: 21px; font-size: 11px; }
    .demo-access-link { height: 32px; padding: 0 10px; font-size: 12px; }
    .demo-banner { align-items: flex-start; flex-direction: column; gap: 10px; }
    .source-file-card {
      align-items: stretch;
      flex-direction: column;
      gap: 12px;
    }
    .source-file-actions {
      justify-content: stretch;
    }
    .source-file-actions a {
      flex: 1 1 120px;
    }
    .status-row { padding: 0 16px 14px; }
    .filter-group { flex-wrap: wrap; }
    .flashcard, .quiz-card { padding: 36px 22px; min-height: 260px; }
    h1.title { font-size: 28px; }
    .item-en { font-size: 16px; }
    .quiz-question { font-size: 22px; }
    .stat { padding-right: 12px; }
    .stat-value { font-size: 22px; }
  }