html, body {
  margin: 0;
  min-height: 100%;
  background: #235390;
  font-family: 'Nunito', system-ui, sans-serif;
}

body {
  padding: 12px;
}

#vtRoot {
  max-width: 1360px;
  margin: 0 auto;
  min-height: calc(100vh - 24px);
}

@media (min-width: 1200px){
  body { padding-left: 20px; padding-right: 20px; }
  .vt-body { padding-left: 36px; padding-right: 36px; }
}
@media (max-width: 720px){
  body { padding: 0; }
  #vtRoot { min-height: 100vh; }
  .vt-root { border-radius: 0; }
}


:root {
  --bg: #FFFFFF;
  --bg-deep: #F7F7F7;
  --surface: #FFFFFF;
  --surface-2: #F0F0F0;
  --surface-3: #E8E8E8;
  --ink: #3C3C3C;
  --ink-2: #4B4B4B;
  --ink-dim: #777777;
  --ink-faint: #AFAFAF;
  --rule: #E5E5E5;
  --rule-soft: #F0F0F0;
  --accent: #58CC02;
  --accent-dark: #58A700;
  --accent-soft: #D7FFB8;
  --blue: #1CB0F6;
  --blue-dark: #1899D6;
  --blue-soft: #DDF4FF;
  --der: #1CB0F6;
  --der-soft: #DDF4FF;
  --die: #FF4B4B;
  --die-soft: #FFDFE0;
  --das: #58CC02;
  --das-soft: #D7FFB8;
  --warn: #FFC800;
  --warn-soft: #FFF4CC;
  --radius: 12px;
  --radius-lg: 16px;
  --serif: 'Nunito', system-ui, sans-serif;
  --sans: 'Nunito', system-ui, sans-serif;
  --mono: 'Nunito', system-ui, sans-serif;
  --shadow: 0 2px 0 #E5E5E5;
  --shadow-btn: 0 4px 0 var(--btn-shadow, #58A700);
}

* { box-sizing: border-box; }

.vt-root {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  min-height: 100%;
  border-radius: 20px;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  line-height: 1.5;
  position: relative;
  box-shadow: 0 8px 0 rgba(0, 0, 0, 0.15);
}

.vt-root * { box-sizing: border-box; }
.vt-root ::selection { background: var(--accent-soft); color: var(--ink); }

/* ---- Header ---- */
.vt-header {
  padding: 20px 24px 16px;
  background: var(--accent);
  color: #fff;
  position: relative;
}

.vt-titlerow {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

.vt-title {
  font-family: var(--sans);
  font-weight: 800;
  font-size: 28px;
  letter-spacing: -0.02em;
  margin: 0;
  line-height: 1.05;
  color: #fff;
}

.vt-title em {
  font-style: normal;
  color: #D7FFB8;
}

.vt-eyebrow {
  font-family: var(--sans);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.85);
  margin-bottom: 4px;
}

.vt-eyebrow em { font-style: normal; }

.vt-overall {
  display: flex;
  align-items: baseline;
  gap: 10px;
  font-family: var(--sans);
  font-size: 13px;
  font-weight: 700;
  color: rgba(255, 255, 255, 0.9);
  white-space: nowrap;
  background: rgba(0, 0, 0, 0.12);
  padding: 8px 14px;
  border-radius: 999px;
}

.vt-overall b {
  color: #fff;
  font-weight: 800;
  font-size: 18px;
}

/* ---- Chapter rail ---- */
.vt-rail {
  margin-top: 14px;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding-bottom: 4px;
  scrollbar-width: thin;
  scrollbar-color: rgba(255,255,255,0.4) transparent;
}

.vt-rail::-webkit-scrollbar { height: 4px; }
.vt-rail::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.45); border-radius: 4px; }

.vt-chip {
  flex: 0 0 auto;
  background: rgba(255, 255, 255, 0.15);
  border: 2px solid transparent;
  border-radius: 14px;
  padding: 8px 14px 10px;
  text-align: left;
  cursor: pointer;
  font-family: var(--sans);
  color: rgba(255, 255, 255, 0.85);
  min-width: 130px;
  position: relative;
  transition: transform 0.15s, background 0.15s, border-color 0.15s;
}

.vt-chip:hover {
  background: rgba(255, 255, 255, 0.25);
  transform: translateY(-1px);
}

.vt-chip:active { transform: translateY(1px); }

.vt-chip.is-active {
  background: #fff;
  color: var(--ink);
  border-color: #fff;
  box-shadow: 0 4px 0 rgba(0, 0, 0, 0.12);
}

.vt-chip-num {
  font-size: 10px;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: inherit;
  opacity: 0.7;
}

.vt-chip.is-active .vt-chip-num { color: var(--accent-dark); opacity: 1; }

.vt-chip-title {
  font-size: 13px;
  font-weight: 700;
  margin-top: 2px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 160px;
}

.vt-chip-progress {
  margin-top: 6px;
  height: 6px;
  background: rgba(0, 0, 0, 0.08);
  border-radius: 999px;
  overflow: hidden;
}

.vt-chip.is-active .vt-chip-progress { background: var(--rule-soft); }

.vt-chip-progress > div {
  height: 100%;
  background: var(--accent);
  border-radius: 999px;
  transition: width 0.35s ease;
}

.vt-chip.is-active .vt-chip-progress > div { background: var(--accent); }

/* ---- Tabs ---- */
.vt-tabs {
  display: flex;
  gap: 4px;
  background: var(--bg-deep);
  padding: 10px 16px;
  border-bottom: 2px solid var(--rule);
  overflow-x: auto;
  scrollbar-width: none;
}

.vt-tabs::-webkit-scrollbar { display: none; }

.vt-tab {
  background: transparent;
  border: none;
  border-radius: 12px;
  padding: 10px 16px;
  font-family: var(--sans);
  font-weight: 700;
  font-size: 14px;
  color: var(--ink-dim);
  cursor: pointer;
  position: relative;
  white-space: nowrap;
  transition: color 0.15s, background 0.15s, transform 0.12s;
}

.vt-tab:hover {
  color: var(--ink);
  background: var(--surface-2);
}

.vt-tab:active { transform: scale(0.97); }

.vt-tab.is-active {
  color: var(--accent-dark);
  background: var(--accent-soft);
}

/* ---- Body ---- */
.vt-body {
  flex: 1;
  padding: 24px;
  min-height: 480px;
  background: var(--bg);
}

/* ---- Generic UI ---- */
.vt-row { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.vt-row + .vt-row { margin-top: 10px; }
.vt-spacer { flex: 1; }

.vt-hint {
  font-size: 12px;
  font-weight: 600;
  color: var(--ink-faint);
}

.vt-rule { height: 2px; background: var(--rule); margin: 18px 0; border-radius: 2px; }

.vt-select {
  font-family: var(--sans);
  font-size: 14px;
  font-weight: 700;
  background: var(--surface);
  color: var(--ink);
  border: 2px solid var(--rule);
  border-radius: 12px;
  padding: 10px 12px;
  cursor: pointer;
  transition: border-color 0.15s;
}

.vt-select:hover { border-color: var(--ink-faint); }

.vt-select:focus-visible,
.vt-btn:focus-visible,
.vt-chip:focus-visible,
.vt-tab:focus-visible,
.vt-typeinput:focus-visible {
  outline: 3px solid var(--blue);
  outline-offset: 2px;
}

.vt-btn {
  font-family: var(--sans);
  font-weight: 800;
  font-size: 14px;
  background: var(--surface);
  color: var(--blue-dark);
  border: 2px solid var(--rule);
  border-bottom-width: 4px;
  border-bottom-color: #D0D0D0;
  border-radius: 14px;
  padding: 10px 18px;
  cursor: pointer;
  transition: transform 0.1s, filter 0.15s, background 0.15s;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  user-select: none;
}

.vt-btn:hover { filter: brightness(0.98); }
.vt-btn:active { transform: translateY(2px); border-bottom-width: 2px; }

.vt-btn-primary {
  background: var(--accent);
  border-color: var(--accent);
  border-bottom-color: var(--accent-dark);
  color: #fff;
}

.vt-btn-primary:hover { filter: brightness(1.03); }

.vt-btn-ghost {
  background: transparent;
  border-bottom-color: var(--rule);
}

.vt-btn:disabled { opacity: 0.45; cursor: default; transform: none; }
.vt-btn.is-on {
  background: var(--accent-soft);
  border-color: var(--accent);
  border-bottom-color: var(--accent-dark);
  color: var(--accent-dark);
}

.vt-iconbtn {
  width: 44px;
  height: 44px;
  border-radius: 14px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--blue-soft);
  border: 2px solid var(--blue);
  border-bottom-width: 4px;
  border-bottom-color: var(--blue-dark);
  cursor: pointer;
  color: var(--blue-dark);
  font-size: 18px;
  flex-shrink: 0;
  transition: transform 0.1s, background 0.15s;
}

.vt-iconbtn:hover { filter: brightness(1.02); }
.vt-iconbtn:active { transform: translateY(2px); border-bottom-width: 2px; }
.vt-iconbtn:disabled { opacity: 0.4; cursor: default; transform: none; }

.vt-iconbtn.is-speaking {
  animation: vt-pulse 0.6s ease infinite;
  background: var(--accent-soft);
  border-color: var(--accent);
  border-bottom-color: var(--accent-dark);
  color: var(--accent-dark);
}

@keyframes vt-pulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.08); }
}

.vt-pill {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 11px;
  font-weight: 800;
  padding: 3px 8px;
  border-radius: 999px;
  letter-spacing: 0.03em;
  text-transform: uppercase;
}

.vt-pill-core { background: var(--warn-soft); color: #B8860B; }
.vt-pill-known { background: var(--das-soft); color: var(--accent-dark); }
.vt-pill-learning { background: var(--blue-soft); color: var(--blue-dark); }
.vt-pill-new { background: var(--surface-2); color: var(--ink-dim); }
.vt-pill-der { background: var(--der-soft); color: var(--blue-dark); }
.vt-pill-die { background: var(--die-soft); color: #CC3D3D; }
.vt-pill-das { background: var(--das-soft); color: var(--accent-dark); }

/* ---- Flashcard ---- */
.vt-cardwrap { display: flex; flex-direction: column; align-items: center; padding-top: 6px; }

.vt-progressline {
  font-size: 12px;
  font-weight: 800;
  color: var(--ink-faint);
  letter-spacing: 0.08em;
  margin-bottom: 14px;
  text-transform: uppercase;
}

.vt-card {
  width: 100%;
  max-width: 560px;
  min-height: 260px;
  background: var(--surface);
  border: 2px solid var(--rule);
  border-bottom-width: 6px;
  border-bottom-color: #D8D8D8;
  border-radius: var(--radius-lg);
  padding: 28px 28px 56px;
  cursor: pointer;
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  transition: transform 0.2s, border-color 0.2s, box-shadow 0.2s;
  user-select: none;
}

.vt-card:hover {
  transform: translateY(-2px);
  border-color: var(--blue);
  border-bottom-color: var(--blue-dark);
}

.vt-card:active { transform: translateY(2px); border-bottom-width: 3px; }

.vt-card-corner-tl { position: absolute; top: 14px; left: 16px; display: flex; gap: 6px; align-items: center; }
.vt-card-corner-tr { position: absolute; top: 14px; right: 16px; display: flex; gap: 6px; align-items: center; }

.vt-card-section {
  font-size: 11px;
  font-weight: 800;
  color: var(--ink-faint);
  margin-bottom: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.vt-card-term {
  font-weight: 800;
  font-size: 34px;
  letter-spacing: -0.02em;
  line-height: 1.15;
  margin: 4px 0 8px;
  color: var(--ink);
}

.vt-card-term .vt-art-der { color: var(--der); font-weight: 800; }
.vt-card-term .vt-art-die { color: var(--die); font-weight: 800; }
.vt-card-term .vt-art-das { color: var(--das); font-weight: 800; }

.vt-card-flipnote {
  font-size: 12px;
  font-weight: 700;
  color: var(--ink-faint);
  margin-top: 12px;
}

.vt-card-back-trans {
  font-size: 22px;
  font-weight: 800;
  color: var(--accent-dark);
  margin-bottom: 14px;
}

.vt-card-example {
  font-size: 16px;
  font-weight: 600;
  color: var(--ink-2);
  max-width: 460px;
  line-height: 1.45;
  border-top: 2px dashed var(--rule);
  padding-top: 14px;
  margin-top: 4px;
}

.vt-card-example-en {
  margin-top: 8px;
  font-weight: 600;
  font-size: 14px;
  color: var(--ink-dim);
}

.vt-card-speak { position: absolute; bottom: 14px; right: 16px; }

.vt-card-forvo {
  position: absolute;
  bottom: 18px;
  left: 16px;
  font-size: 11px;
  font-weight: 800;
  color: var(--ink-faint);
  text-decoration: none;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.vt-card-forvo:hover { color: var(--blue-dark); }

.vt-cardnav { display: flex; align-items: center; gap: 16px; margin-top: 22px; }
.vt-statusrow { display: flex; gap: 8px; flex-wrap: wrap; justify-content: center; }

/* ---- Quiz / Type ---- */
.vt-qsetup, .vt-qarea { max-width: 580px; margin: 0 auto; }

.vt-scorebar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 12px;
  font-weight: 800;
  color: var(--ink-dim);
  margin-bottom: 16px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.vt-scorebar b { color: var(--ink); font-size: 16px; text-transform: none; }

.vt-qprompt {
  background: var(--bg-deep);
  border: 2px solid var(--rule);
  border-radius: var(--radius-lg);
  padding: 28px 24px;
  text-align: center;
  margin-bottom: 16px;
  position: relative;
}

.vt-qprompt-label {
  font-size: 11px;
  font-weight: 800;
  color: var(--ink-faint);
  margin-bottom: 12px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.vt-qprompt-main {
  font-weight: 800;
  font-size: 28px;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

.vt-qprompt-example {
  font-size: 14px;
  font-weight: 600;
  color: var(--ink-dim);
  margin-top: 10px;
  line-height: 1.45;
}

.vt-qprompt-speak { position: absolute; top: 14px; right: 14px; }

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

.vt-option {
  text-align: left;
  background: var(--surface);
  border: 2px solid var(--rule);
  border-bottom-width: 4px;
  border-bottom-color: #D8D8D8;
  border-radius: 14px;
  padding: 14px 16px;
  font-family: var(--sans);
  font-size: 15px;
  font-weight: 700;
  color: var(--ink);
  cursor: pointer;
  transition: transform 0.1s, border-color 0.12s, background 0.12s;
}

.vt-option:hover:not(:disabled) {
  border-color: var(--blue);
  border-bottom-color: var(--blue-dark);
  background: var(--blue-soft);
}

.vt-option:active:not(:disabled) { transform: translateY(2px); border-bottom-width: 2px; }
.vt-option:disabled { cursor: default; }

.vt-option.is-correct {
  border-color: var(--accent);
  border-bottom-color: var(--accent-dark);
  background: var(--accent-soft);
  color: var(--accent-dark);
}

.vt-option.is-wrong {
  border-color: var(--die);
  border-bottom-color: #CC3D3D;
  background: var(--die-soft);
  color: #CC3D3D;
}

.vt-typeinput {
  width: 100%;
  font-family: var(--sans);
  font-size: 20px;
  font-weight: 700;
  background: var(--surface);
  color: var(--ink);
  border: 2px solid var(--rule);
  border-bottom-width: 4px;
  border-bottom-color: #D8D8D8;
  border-radius: 14px;
  padding: 14px 16px;
  transition: border-color 0.15s;
}

.vt-typeinput:focus {
  outline: none;
  border-color: var(--blue);
  border-bottom-color: var(--blue-dark);
}

.vt-typeinput.is-correct {
  border-color: var(--accent);
  border-bottom-color: var(--accent-dark);
  background: var(--accent-soft);
}

.vt-typeinput.is-wrong {
  border-color: var(--die);
  border-bottom-color: #CC3D3D;
  background: var(--die-soft);
}

.vt-typefeedback { margin-top: 10px; font-size: 15px; font-weight: 700; }
.vt-typefeedback.ok { color: var(--accent-dark); }
.vt-typefeedback.partial { color: #B8860B; }
.vt-typefeedback.bad { color: #CC3D3D; }

.vt-qend { text-align: center; padding: 30px 0; }

.vt-qend-score {
  font-weight: 800;
  font-size: 56px;
  color: var(--accent);
  letter-spacing: -0.03em;
  line-height: 1;
}

.vt-qend-label {
  font-size: 13px;
  font-weight: 800;
  color: var(--ink-faint);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-top: 10px;
}

/* ---- Match ---- */
.vt-matchhead {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 12px;
  font-weight: 800;
  color: var(--ink-dim);
  margin-bottom: 16px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  max-width: 640px;
  margin-left: auto;
  margin-right: auto;
}

.vt-matchgrid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  max-width: 640px;
  margin: 0 auto;
}

.vt-matchcol { display: flex; flex-direction: column; gap: 10px; }

.vt-matchcard {
  background: var(--surface);
  border: 2px solid var(--rule);
  border-bottom-width: 4px;
  border-bottom-color: #D8D8D8;
  border-radius: 14px;
  padding: 14px;
  font-size: 15px;
  font-weight: 700;
  cursor: pointer;
  text-align: left;
  transition: transform 0.1s, all 0.12s;
  min-height: 52px;
  display: flex;
  align-items: center;
}

.vt-matchcard.is-de { font-size: 16px; font-weight: 800; }

.vt-matchcard:hover:not(.is-matched):not(.is-selected) {
  border-color: var(--blue);
  border-bottom-color: var(--blue-dark);
  background: var(--blue-soft);
}

.vt-matchcard:active:not(.is-matched) { transform: translateY(2px); border-bottom-width: 2px; }

.vt-matchcard.is-selected {
  border-color: var(--blue);
  border-bottom-color: var(--blue-dark);
  background: var(--blue-soft);
}

.vt-matchcard.is-matched {
  border-color: var(--accent);
  border-bottom-color: var(--accent-dark);
  background: var(--accent-soft);
  color: var(--accent-dark);
  opacity: 0.75;
  cursor: default;
}

.vt-matchcard.is-wrong {
  border-color: var(--die);
  border-bottom-color: #CC3D3D;
  background: var(--die-soft);
  animation: vt-shake 0.35s ease;
}

@keyframes vt-shake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-4px); }
  75% { transform: translateX(4px); }
}

/* ---- Artikel trainer ---- */
.vt-artwrap { display: flex; flex-direction: column; align-items: center; padding-top: 6px; max-width: 580px; margin: 0 auto; }

.vt-artprogress {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 12px;
  font-weight: 800;
  color: var(--ink-dim);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 18px;
}

.vt-artstats { display: flex; gap: 10px; flex-wrap: wrap; }
.vt-artstat { display: flex; align-items: center; gap: 4px; }
.vt-artstat b { font-size: 14px; font-weight: 800; text-transform: none; }

.vt-artcard {
  width: 100%;
  background: var(--bg-deep);
  border: 2px solid var(--rule);
  border-bottom-width: 6px;
  border-bottom-color: #D8D8D8;
  border-radius: var(--radius-lg);
  padding: 32px 24px 28px;
  text-align: center;
  position: relative;
}

.vt-artnoun {
  font-weight: 800;
  font-size: 40px;
  letter-spacing: -0.02em;
  line-height: 1.1;
  margin: 8px 0 4px;
}

.vt-artnoun.is-revealed .vt-art-prefix { font-weight: 800; }
.vt-artnoun.is-revealed .vt-art-prefix.vt-art-der { color: var(--der); }
.vt-artnoun.is-revealed .vt-art-prefix.vt-art-die { color: var(--die); }
.vt-artnoun.is-revealed .vt-art-prefix.vt-art-das { color: var(--das); }

.vt-artplural { font-size: 14px; font-weight: 700; color: var(--ink-dim); margin-top: 4px; }
.vt-arttrans { font-size: 15px; font-weight: 700; color: var(--ink-dim); margin-top: 14px; }

.vt-artexample {
  font-size: 15px;
  font-weight: 600;
  color: var(--ink-2);
  margin-top: 16px;
  max-width: 480px;
  margin-left: auto;
  margin-right: auto;
  border-top: 2px dashed var(--rule);
  padding-top: 14px;
  line-height: 1.45;
}

.vt-arthint {
  margin-top: 16px;
  background: var(--warn-soft);
  border-left: 4px solid var(--warn);
  padding: 12px 14px;
  text-align: left;
  font-size: 14px;
  font-weight: 600;
  color: var(--ink-2);
  border-radius: 0 12px 12px 0;
}

.vt-arthint b { color: #B8860B; font-weight: 800; }

.vt-artbuttons {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 10px;
  margin-top: 24px;
}

.vt-artbtn {
  font-weight: 800;
  font-size: 24px;
  padding: 18px 0;
  border-radius: 14px;
  border: 2px solid;
  border-bottom-width: 5px;
  background: var(--surface);
  cursor: pointer;
  transition: transform 0.1s, background 0.12s;
}

.vt-artbtn[data-art="der"] { color: var(--der); border-color: var(--der); border-bottom-color: var(--blue-dark); }
.vt-artbtn[data-art="die"] { color: var(--die); border-color: var(--die); border-bottom-color: #CC3D3D; }
.vt-artbtn[data-art="das"] { color: var(--das); border-color: var(--das); border-bottom-color: var(--accent-dark); }

.vt-artbtn:hover:not(:disabled) { filter: brightness(1.02); transform: translateY(-1px); }
.vt-artbtn:active:not(:disabled) { transform: translateY(3px); border-bottom-width: 2px; }
.vt-artbtn:disabled { opacity: 0.5; cursor: default; transform: none; }

.vt-artbtn.is-correct[data-art="der"],
.vt-artbtn.is-correct[data-art="die"],
.vt-artbtn.is-correct[data-art="das"] {
  background: var(--accent);
  border-color: var(--accent);
  border-bottom-color: var(--accent-dark);
  color: #fff;
}

.vt-artbtn.is-wrong {
  background: var(--die-soft);
  color: #CC3D3D;
  border-color: var(--die);
  border-bottom-color: #CC3D3D;
}

.vt-artnav { margin-top: 20px; display: flex; justify-content: center; gap: 10px; flex-wrap: wrap; }

.vt-artmodeselect { display: flex; gap: 8px; margin-bottom: 18px; flex-wrap: wrap; justify-content: center; }

.vt-artmodebtn {
  background: var(--surface);
  border: 2px solid var(--rule);
  border-bottom-width: 4px;
  border-bottom-color: #D8D8D8;
  border-radius: 12px;
  padding: 8px 14px;
  font-family: var(--sans);
  font-size: 13px;
  font-weight: 800;
  color: var(--ink-dim);
  cursor: pointer;
  transition: transform 0.1s;
}

.vt-artmodebtn.is-on {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
  border-bottom-color: var(--accent-dark);
}

.vt-artmodebtn:active { transform: translateY(2px); border-bottom-width: 2px; }

/* ---- Stats ---- */
.vt-statsgrid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
  margin-bottom: 24px;
}

.vt-statcard {
  background: var(--bg-deep);
  border: 2px solid var(--rule);
  border-bottom-width: 4px;
  border-bottom-color: #D8D8D8;
  border-radius: var(--radius-lg);
  padding: 16px;
  transition: transform 0.15s;
}

.vt-statcard:hover { transform: translateY(-2px); }

.vt-statcard .vt-statnum {
  font-weight: 800;
  font-size: 32px;
  letter-spacing: -0.02em;
  line-height: 1;
}

.vt-statcard .vt-statlabel {
  font-size: 11px;
  font-weight: 800;
  color: var(--ink-faint);
  margin-top: 6px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.vt-chaptertable { display: flex; flex-direction: column; gap: 0; border-top: 2px solid var(--rule); }

.vt-chrow {
  display: grid;
  grid-template-columns: 30px 1fr 240px 50px;
  align-items: center;
  gap: 14px;
  padding: 12px 4px;
  border-bottom: 2px solid var(--rule-soft);
  font-size: 14px;
  font-weight: 700;
  cursor: pointer;
  transition: background 0.12s, transform 0.12s;
  border-radius: 8px;
}

.vt-chrow:hover { background: var(--accent-soft); transform: translateX(4px); }

.vt-chrow-num { color: var(--ink-faint); font-size: 12px; font-weight: 800; }
.vt-chrow-title { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }

.vt-chrow-bar {
  height: 10px;
  background: var(--surface-2);
  overflow: hidden;
  display: flex;
  border-radius: 999px;
}

.vt-chrow-bar .seg-known { background: var(--accent); transition: width 0.35s; }
.vt-chrow-bar .seg-learning { background: var(--blue); transition: width 0.35s; }

.vt-chrow-pct { color: var(--ink-dim); text-align: right; font-size: 13px; font-weight: 800; }

.vt-empty {
  text-align: center;
  color: var(--ink-faint);
  padding: 50px 20px;
  font-size: 16px;
  font-weight: 700;
}

.vt-storage-note {
  margin-top: 18px;
  padding: 12px 14px;
  background: var(--blue-soft);
  border-left: 4px solid var(--blue);
  font-size: 13px;
  font-weight: 600;
  color: var(--ink-dim);
  border-radius: 0 12px 12px 0;
}

@media (max-width: 680px) {
  body { padding: 8px; }
  .vt-header { padding: 16px; }
  .vt-tabs { padding: 8px 12px; }
  .vt-body { padding: 16px; }
  .vt-statsgrid { grid-template-columns: repeat(2, 1fr); }
  .vt-chrow { grid-template-columns: 22px 1fr 90px 40px; gap: 8px; font-size: 12px; }
  .vt-title { font-size: 22px; }
  .vt-card-term { font-size: 26px; }
  .vt-artnoun { font-size: 30px; }
  .vt-matchgrid { gap: 8px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation: none !important;
    transition: none !important;
  }
}



/* ===== Standalone interactive upgrade ===== */
html, body { min-height: 100%; }
body { padding: 18px; background: radial-gradient(circle at 15% 10%, #58cc02 0, #235390 36%, #12345f 100%); }
#vtRoot { max-width: 1180px; min-height: calc(100vh - 36px); }
.vt-root { border-radius: 28px; box-shadow: 0 18px 0 rgba(0,0,0,.18), 0 28px 80px rgba(0,0,0,.25); }
.vt-header { padding: 26px 30px 18px; background: linear-gradient(135deg, #58CC02 0%, #1CB0F6 100%); }
.vt-title { font-size: clamp(32px, 5vw, 58px); }
.vt-eyebrow { font-size: 12px; }
.vt-overall { font-size: 16px; padding: 10px 16px; }
.vt-overall b { font-size: 24px; }
.vt-chip { min-width: 152px; border-radius: 18px; }
.vt-tabs { padding: 14px 22px; gap: 8px; }
.vt-tab { font-size: 16px; padding: 12px 20px; border-radius: 16px; }
.vt-body { padding: clamp(18px, 3.2vw, 38px); }
.vt-topbar { max-width: 900px; margin: 0 auto 18px; }
.vt-big-stage { padding-top: 0; }
.vt-supercard {
  max-width: 840px;
  min-height: clamp(360px, 52vh, 560px);
  border-radius: 30px;
  border-width: 3px;
  border-bottom-width: 10px;
  padding: 54px clamp(22px, 4vw, 58px) 86px;
  background:
    radial-gradient(circle at 88% 15%, rgba(28,176,246,.14), transparent 28%),
    radial-gradient(circle at 10% 85%, rgba(88,204,2,.14), transparent 28%),
    linear-gradient(180deg, #ffffff 0%, #fbfffa 100%);
  box-shadow: 0 18px 40px rgba(20, 40, 80, .08);
}
.vt-supercard:hover { transform: translateY(-4px); box-shadow: 0 24px 50px rgba(20,40,80,.13); }
.vt-supercard.is-flipped { border-color: var(--accent); border-bottom-color: var(--accent-dark); }
.vt-hero-word, .vt-supercard .vt-card-term {
  font-size: clamp(48px, 8.4vw, 94px);
  line-height: .98;
  letter-spacing: -.055em;
  max-width: 100%;
  overflow-wrap: anywhere;
}
.vt-card-term-back { font-size: clamp(34px, 4.7vw, 58px) !important; line-height: 1.05; }
.vt-card-back-trans { font-size: clamp(28px, 4vw, 46px); margin: 10px 0 18px; }
.vt-card-example { max-width: 700px; font-size: clamp(17px, 2vw, 24px); }
.vt-card-example-en { font-size: clamp(15px, 1.6vw, 18px); }
.vt-card-flipnote { font-size: 16px; margin-top: 24px; background: var(--blue-soft); color: var(--blue-dark); padding: 9px 14px; border-radius: 999px; }
.vt-card-section { font-size: 13px; margin-bottom: 20px; }
.vt-pill { font-size: 13px; padding: 5px 11px; }
.vt-card-corner-tl, .vt-card-corner-tr { top: 18px; }
.vt-card-corner-tl { left: 22px; }
.vt-card-corner-tr { right: 22px; }
.vt-card-forvo { left: 24px; bottom: 25px; font-size: 13px; background: var(--surface-2); padding: 9px 12px; border-radius: 999px; }
.vt-speak-big { width: auto; min-width: 72px; height: 54px; gap: 8px; padding: 0 16px; border-radius: 18px; font-weight: 900; }
.vt-speak-big span { font-size: 14px; }
.vt-card-speak { right: 24px; bottom: 20px; position: absolute; }
.vt-wide-nav { gap: 22px; margin-top: 26px; }
.vt-wide-nav .vt-iconbtn { width: 56px; height: 56px; border-radius: 18px; font-size: 24px; }
.vt-wide-nav .vt-btn { font-size: 16px; padding: 14px 22px; }
.vt-smallbtn { padding: 6px 12px !important; font-size: 12px !important; }
.vt-mode-title { margin: 0 0 8px; font-size: clamp(30px, 5vw, 48px); letter-spacing: -.03em; text-align:center; }
.vt-mode-copy { max-width: 640px; text-align: center; color: var(--ink-dim); font-weight: 700; margin: 0 auto 24px; }
.vt-artcard { max-width: 780px; margin: 0 auto; }
.vt-artnoun { font-size: clamp(52px, 8vw, 90px); }
.vt-arttrans { font-size: clamp(26px, 4vw, 42px); }
.vt-qsetup, .vt-qarea { max-width: 820px; }
.vt-qprompt { border-radius: 26px; }
.vt-qprompt-main { font-size: clamp(36px, 6vw, 70px); }
.vt-options { gap: 14px; }
.vt-option { font-size: 19px; border-radius: 18px; padding: 17px 18px; }
.vt-matchgrid { max-width: 980px; margin: 22px auto 0; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 14px; }
.vt-matchcard { min-height: 86px; font-size: clamp(16px, 2vw, 22px); }
.vt-typeinput { font-size: 28px; min-height: 68px; border-radius: 18px; }
.vt-mini-notice { position:absolute; left:50%; bottom:24px; transform:translateX(-50%) translateY(18px); opacity:0; pointer-events:none; background:#111827; color:#fff; padding:12px 18px; border-radius:999px; font-size:14px; font-weight:800; box-shadow:0 12px 35px rgba(0,0,0,.22); transition:opacity .2s ease, transform .2s ease; z-index:99; max-width:min(760px, calc(100% - 32px)); text-align:center; }
.vt-mini-notice.is-showing { opacity:1; transform:translateX(-50%) translateY(0); }
.vt-iconbtn.is-speaking { animation: vt-soundwave .58s ease infinite; background: var(--accent-soft); border-color: var(--accent); border-bottom-color: var(--accent-dark); color: var(--accent-dark); }
@keyframes vt-soundwave { 0%,100% { transform: scale(1); } 50% { transform: scale(1.08); } }
@media (max-width: 760px){ body{padding:8px;} #vtRoot{min-height:calc(100vh - 16px);} .vt-matchgrid{grid-template-columns:1fr 1fr;} .vt-supercard{min-height:390px;} .vt-card-forvo{bottom:18px;} .vt-card-speak{bottom:14px;} .vt-speak-big span{display:none;} .vt-speak-big{min-width:54px;width:54px;padding:0;} }

  

/* ---- Small study packs + backup tools ---- */
.vt-studybar {
  display: grid;
  grid-template-columns: minmax(160px, 1fr) minmax(210px, 1.4fr) auto auto;
  gap: 10px;
  align-items: center;
  margin-bottom: 14px;
}
.vt-pack-note {
  max-width: 840px;
  margin: 0 auto 14px;
  padding: 12px 16px;
  border: 2px solid var(--blue-soft);
  border-radius: 18px;
  background: linear-gradient(90deg, var(--blue-soft), #fff);
  color: var(--ink-2);
  font-size: 14px;
  font-weight: 800;
  display: flex;
  gap: 10px;
  align-items: center;
  justify-content: space-between;
}
.vt-pack-note b { color: var(--blue-dark); }
.vt-pack-pill {
  display:inline-flex;
  align-items:center;
  justify-content:center;
  min-width: 42px;
  padding: 5px 10px;
  border-radius: 999px;
  background: #fff;
  border: 2px solid var(--blue-soft);
  color: var(--blue-dark);
  font-weight: 900;
}
.vt-pack-dots {
  display: flex;
  gap: 4px;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  margin-top: 9px;
}
.vt-pack-dot {
  width: 8px;
  height: 8px;
  border-radius: 999px;
  background: var(--surface-3);
}
.vt-pack-dot.is-learning { background: var(--blue); }
.vt-pack-dot.is-known { background: var(--accent); }
.vt-save-panel {
  max-width: 920px;
  margin: 22px auto 0;
  padding: 18px;
  border: 2px solid var(--rule);
  border-radius: 22px;
  background: #fff;
  box-shadow: var(--shadow);
}
.vt-save-panel h3 { margin: 0 0 6px; font-size: 22px; }
.vt-save-panel p { margin: 0 0 12px; color: var(--ink-dim); font-weight: 700; }
.vt-save-actions { display:flex; gap:10px; flex-wrap:wrap; align-items:center; }
.vt-file-input { display:none; }
.vt-save-ok { color: var(--accent-dark); font-weight:900; }
.vt-save-warn { color: #b45309; font-weight:900; }
.vt-progress-mini { color: var(--ink-dim); font-size: 13px; font-weight: 800; text-align: center; margin-top: 8px; }
@media (max-width: 760px){
  .vt-studybar { grid-template-columns: 1fr; }
  .vt-pack-note { align-items:flex-start; flex-direction:column; }
}


/* ---- Block paragraph / reading mode ---- */
.vt-read-card {
  max-width: 1220px;
  margin: 0 auto;
  background: linear-gradient(135deg, #ffffff 0%, #f7fff1 48%, #eef8ff 100%);
  border: 2px solid var(--rule);
  border-radius: 24px;
  padding: 26px;
  box-shadow: 0 8px 0 rgba(0,0,0,0.08);
}
.vt-read-head {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 16px;
  margin-bottom: 16px;
  flex-wrap: wrap;
}
.vt-read-title {
  margin: 0;
  font-size: 28px;
  line-height: 1.1;
  font-weight: 900;
  color: var(--ink);
}
.vt-read-sub {
  margin-top: 6px;
  font-size: 13px;
  font-weight: 800;
  color: var(--ink-dim);
  letter-spacing: .03em;
}
.vt-read-level {
  background: var(--accent-soft);
  color: var(--accent-dark);
  border-radius: 999px;
  padding: 8px 12px;
  font-size: 12px;
  font-weight: 900;
  white-space: nowrap;
}
.vt-read-text {
  background: rgba(255,255,255,.82);
  border: 2px solid var(--rule-soft);
  border-radius: 20px;
  padding: 22px;
  font-size: 22px;
  line-height: 1.72;
  font-weight: 750;
  color: var(--ink);
}
.vt-read-text mark {
  background: #DDF4FF;
  color: #0b74a5;
  border-radius: 10px;
  padding: 1px 6px;
  font-weight: 900;
}

.vt-term-mark {
  position: relative;
  cursor: help;
  border-bottom: 2px dotted rgba(11,116,165,.35);
  transition: transform .12s ease, background .12s ease;
}
.vt-term-mark:hover,
.vt-term-mark:focus {
  background: #C8EDFF;
  transform: translateY(-1px);
  outline: none;
}
.vt-term-mark::after {
  content: attr(data-tip);
  position: absolute;
  left: 50%;
  bottom: calc(100% + 10px);
  transform: translateX(-50%) translateY(4px);
  opacity: 0;
  pointer-events: none;
  z-index: 20;
  min-width: 170px;
  max-width: 280px;
  white-space: normal;
  background: #1f2937;
  color: #fff;
  border-radius: 14px;
  padding: 10px 12px;
  font-size: 13px;
  line-height: 1.35;
  font-weight: 850;
  box-shadow: 0 8px 18px rgba(0,0,0,.2);
}
.vt-term-mark::before {
  content: '';
  position: absolute;
  left: 50%;
  bottom: calc(100% + 4px);
  transform: translateX(-50%) translateY(4px);
  opacity: 0;
  pointer-events: none;
  z-index: 21;
  border: 6px solid transparent;
  border-top-color: #1f2937;
}
.vt-term-mark:hover::after,
.vt-term-mark:hover::before,
.vt-term-mark:focus::after,
.vt-term-mark:focus::before {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}
.vt-read-layout {
  display: grid;
  grid-template-columns: minmax(620px, 1fr) minmax(360px, 420px);
  gap: 24px;
  align-items: start;
}
.vt-read-main { min-width: 0; }
.vt-read-side {
  position: sticky;
  top: 14px;
  min-width: 0;
}
.vt-read-side .vt-chat-panel {
  margin-top: 0;
}
.vt-read-side .vt-chat-log {
  max-height: 520px;
}
@media (max-width: 1120px){
  .vt-read-layout { grid-template-columns: 1fr; }
  .vt-read-side { position: static; }
  .vt-read-side .vt-chat-log { max-height: 310px; }
}

/* All-word hover in reading paragraphs */
.vt-word-tip {
  position: relative;
  display: inline-block;
  border-radius: 8px;
  padding: 0 1px;
  cursor: help;
  transition: background .12s ease, transform .12s ease;
}
.vt-word-tip:not(.vt-term-mark) {
  border-bottom: 1.5px dotted rgba(120,120,120,.25);
}
.vt-word-tip:not(.vt-term-mark):hover,
.vt-word-tip:not(.vt-term-mark):focus {
  background: var(--warn-soft);
  outline: none;
}
.vt-word-tip::after {
  content: attr(data-tip);
  position: absolute;
  left: 50%;
  bottom: calc(100% + 10px);
  transform: translateX(-50%) translateY(4px);
  opacity: 0;
  pointer-events: none;
  z-index: 60;
  min-width: 150px;
  max-width: 300px;
  white-space: normal;
  background: #1f2937;
  color: #fff;
  border-radius: 14px;
  padding: 10px 12px;
  font-size: 13px;
  line-height: 1.35;
  font-weight: 850;
  box-shadow: 0 8px 18px rgba(0,0,0,.2);
}
.vt-word-tip::before {
  content: '';
  position: absolute;
  left: 50%;
  bottom: calc(100% + 4px);
  transform: translateX(-50%) translateY(4px);
  opacity: 0;
  pointer-events: none;
  z-index: 61;
  border: 6px solid transparent;
  border-top-color: #1f2937;
}
.vt-word-tip:hover::after,
.vt-word-tip:hover::before,
.vt-word-tip:focus::after,
.vt-word-tip:focus::before {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}
.vt-word-tip.vt-term-mark {
  background: #DDF4FF;
  color: #0b74a5;
  border-bottom: 2px dotted rgba(11,116,165,.35);
  padding: 1px 6px;
  font-weight: 900;
}
.vt-word-tip.vt-term-mark:hover,
.vt-word-tip.vt-term-mark:focus {
  background: #C8EDFF;
  transform: translateY(-1px);
  outline: none;
}
.vt-word-tip.is-unknown::after { content: attr(data-tip); }

.vt-read-en {
  margin-top: 14px;
  background: #fff;
  border: 2px dashed var(--rule);
  border-radius: 18px;
  padding: 16px 18px;
  color: var(--ink-2);
  font-size: 15px;
  line-height: 1.65;
  font-weight: 700;
}
.vt-read-words {
  margin-top: 16px;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.vt-read-word {
  border: 2px solid var(--rule);
  border-radius: 999px;
  padding: 7px 11px;
  background: #fff;
  font-size: 13px;
  font-weight: 850;
  color: var(--ink);
}
.vt-read-word span {
  color: var(--ink-dim);
  font-weight: 750;
}

.vt-ai-panel {
  margin-top: 18px;
  padding: 16px;
  border: 2px solid var(--blue-soft);
  border-radius: 20px;
  background: rgba(221,244,255,.55);
}
.vt-ai-panel h4 {
  margin: 0 0 6px;
  font-size: 17px;
  font-weight: 900;
  color: var(--ink);
}
.vt-ai-panel p {
  margin: 0 0 12px;
  font-size: 13px;
  font-weight: 750;
  color: var(--ink-dim);
}
.vt-ai-grid {
  display: grid;
  grid-template-columns: minmax(180px, 1fr) auto auto auto;
  gap: 10px;
  align-items: center;
}
.vt-ai-input {
  width: 100%;
  min-height: 48px;
  border: 2px solid var(--rule);
  border-radius: 14px;
  padding: 10px 12px;
  font-family: var(--sans);
  font-size: 14px;
  font-weight: 750;
  outline: none;
  background: #fff;
}
.vt-ai-input:focus {
  border-color: var(--blue);
  box-shadow: 0 0 0 4px var(--blue-soft);
}
.vt-ai-check {
  display: flex;
  gap: 7px;
  align-items: center;
  font-size: 13px;
  font-weight: 850;
  color: var(--ink-dim);
  white-space: nowrap;
}
.vt-ai-status {
  margin-top: 10px;
  font-size: 13px;
  font-weight: 850;
  color: var(--blue-dark);
}
.vt-ai-error {
  color: #b91c1c;
}
.vt-ai-good {
  color: var(--accent-dark);
}
.vt-ai-badge {
  background: var(--blue-soft);
  color: var(--blue-dark);
  border-radius: 999px;
  padding: 8px 12px;
  font-size: 12px;
  font-weight: 900;
  white-space: nowrap;
}
.vt-ai-questions {
  margin-top: 14px;
  padding: 14px 18px;
  border: 2px dashed var(--rule);
  border-radius: 18px;
  background: rgba(255,255,255,.72);
  font-size: 15px;
  font-weight: 750;
}
.vt-ai-questions b { font-weight: 900; }
.vt-ai-questions ol { margin: 8px 0 0 20px; padding: 0; }
@media (max-width: 760px){
  .vt-ai-grid { grid-template-columns: 1fr; }
  .vt-ai-check { white-space: normal; }
}


/* ---- AI tutor chat ---- */
.vt-chat-panel {
  margin-top: 16px;
  background: #fff;
  border: 2px solid var(--rule);
  border-radius: 18px;
  padding: 16px;
  box-shadow: var(--shadow);
}
.vt-chat-panel h4 {
  margin: 0 0 4px;
  font-size: 18px;
  font-weight: 900;
  color: var(--ink);
}
.vt-chat-panel p {
  margin: 0 0 12px;
  color: var(--ink-dim);
  font-weight: 700;
  font-size: 13px;
}
.vt-chat-quick {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin: 8px 0 12px;
}
.vt-chat-chip {
  border: 2px solid var(--rule);
  background: var(--bg-deep);
  color: var(--blue-dark);
  border-radius: 999px;
  padding: 8px 10px;
  font-weight: 900;
  cursor: pointer;
  box-shadow: 0 2px 0 var(--rule);
}
.vt-chat-chip:hover { background: var(--blue-soft); border-color: var(--blue); }
.vt-chat-log {
  min-height: 88px;
  max-height: 310px;
  overflow-y: auto;
  background: linear-gradient(180deg, #FFFFFF, #F8FCFF);
  border: 2px solid var(--rule-soft);
  border-radius: 16px;
  padding: 12px;
}
.vt-chat-empty {
  color: var(--ink-dim);
  font-weight: 800;
  font-size: 14px;
  text-align: center;
  padding: 20px 8px;
}
.vt-chat-msg {
  max-width: 86%;
  margin: 8px 0;
  padding: 10px 12px;
  border-radius: 16px;
  font-size: 14px;
  line-height: 1.45;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}
.vt-chat-msg.user {
  margin-left: auto;
  background: var(--blue);
  color: #fff;
  border-bottom-right-radius: 6px;
  font-weight: 800;
}
.vt-chat-msg.assistant {
  margin-right: auto;
  background: var(--accent-soft);
  color: var(--ink);
  border-bottom-left-radius: 6px;
  border: 2px solid #C6F6A6;
  font-weight: 700;
}
.vt-chat-form {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 10px;
  margin-top: 12px;
  align-items: end;
}
.vt-chat-input {
  width: 100%;
  min-height: 58px;
  resize: vertical;
  border: 2px solid var(--rule);
  border-radius: 14px;
  padding: 12px 14px;
  font: 800 15px var(--sans);
  color: var(--ink);
  outline: none;
}
.vt-chat-input:focus { border-color: var(--blue); box-shadow: 0 0 0 4px var(--blue-soft); }
.vt-chat-status {
  margin-top: 8px;
  font-size: 12px;
  font-weight: 900;
  color: var(--blue-dark);
}
.vt-chat-error { color: #d23b3b; }

@media (max-width: 700px){
  .vt-read-card { padding: 18px; }
  .vt-read-title { font-size: 22px; }
  .vt-read-text { font-size: 19px; padding: 16px; }
}


/* ===== Full-width reading/tutor layout fix ===== */
@media (min-width: 1000px){
  body {
    padding: 12px;
    background:
      radial-gradient(circle at 6% 8%, #58cc02 0, rgba(88,204,2,.75) 16%, transparent 32%),
      linear-gradient(135deg, #0a8f5a 0%, #123c75 45%, #233b82 100%);
  }
  #vtRoot {
    width: calc(100vw - 24px);
    max-width: 1660px;
    margin-left: auto;
    margin-right: auto;
  }
  .vt-body {
    padding-left: clamp(20px, 2.2vw, 42px);
    padding-right: clamp(20px, 2.2vw, 42px);
  }
  .vt-read-page {
    width: 100%;
    max-width: 1540px !important;
    margin-left: auto;
    margin-right: auto;
  }
  .vt-read-page .vt-mode-copy {
    max-width: 860px;
  }
  .vt-read-page .vt-studybar,
  .vt-read-page .vt-pack-note {
    max-width: 1240px;
    margin-left: auto;
    margin-right: auto;
  }
  .vt-read-card {
    width: 100%;
    max-width: 1540px;
    padding: clamp(22px, 2vw, 34px);
  }
  .vt-read-layout {
    grid-template-columns: minmax(720px, 1fr) minmax(390px, 450px);
    gap: clamp(22px, 2.2vw, 36px);
  }
  .vt-read-text {
    font-size: clamp(22px, 1.45vw, 27px);
    line-height: 1.62;
    padding: clamp(22px, 2vw, 32px);
  }
  .vt-read-side {
    width: 100%;
    min-width: 0;
  }
  .vt-read-side .vt-chat-panel {
    width: 100%;
    overflow: hidden;
    border-radius: 24px;
    padding: 18px;
  }
  .vt-read-side .vt-chat-log {
    max-height: min(58vh, 560px);
  }
  .vt-chat-form {
    grid-template-columns: minmax(0, 1fr) auto;
  }
  .vt-chat-input {
    min-width: 0;
  }
  .vt-chat-quick {
    flex-wrap: wrap;
  }
}

@media (min-width: 1500px){
  #vtRoot { max-width: 1700px; }
  .vt-read-page, .vt-read-card { max-width: 1600px !important; }
  .vt-read-layout { grid-template-columns: minmax(840px, 1fr) 460px; }
}

@media (max-width: 999px){
  .vt-read-page { max-width: 100% !important; }
  .vt-read-layout { grid-template-columns: 1fr; }
  .vt-read-side { position: static; }
}


/* ===== vNext: true full-screen reading layout ===== */
body {
  padding: 0 !important;
  overflow-x: hidden;
}
#vtRoot {
  width: 100vw !important;
  max-width: none !important;
  margin: 0 !important;
  border-radius: 0 !important;
  min-height: 100vh !important;
}
.vt-root {
  border-radius: 0 !important;
}
.vt-body {
  padding-left: clamp(16px, 3vw, 56px) !important;
  padding-right: clamp(16px, 3vw, 56px) !important;
}
.vt-read-page {
  width: 100% !important;
  max-width: none !important;
}
.vt-read-card {
  width: 100% !important;
  max-width: none !important;
}
.vt-read-page .vt-studybar,
.vt-read-page .vt-pack-note {
  max-width: 1320px !important;
}
@media (min-width: 760px){
  .vt-read-layout {
    grid-template-columns: minmax(0, 1fr) clamp(340px, 28vw, 520px) !important;
    gap: clamp(18px, 2.5vw, 44px) !important;
  }
  .vt-read-side {
    position: sticky !important;
    top: 16px !important;
  }
  .vt-read-text {
    font-size: clamp(21px, 1.55vw, 30px) !important;
    line-height: 1.64 !important;
  }
}
@media (min-width: 1300px){
  .vt-read-layout {
    grid-template-columns: minmax(760px, 1fr) clamp(420px, 27vw, 540px) !important;
  }
}
@media (max-width: 759px){
  .vt-read-layout { grid-template-columns: 1fr !important; }
  .vt-read-side { position: static !important; }
}

  

/* ===== Duolingo-style visual refresh ===== */
html, body {
  background:
    radial-gradient(circle at 15% 20%, rgba(88,204,2,.22), transparent 28%),
    radial-gradient(circle at 85% 15%, rgba(28,176,246,.22), transparent 26%),
    linear-gradient(180deg, #02c82a 0%, #159fe7 100%);
}

:root {
  --bg: #f7fff5;
  --bg-deep: #eef8eb;
  --surface: #ffffff;
  --surface-2: #f5fbff;
  --surface-3: #edf7ff;
  --rule: #dfeee1;
  --rule-soft: #edf6ef;
}

.vt-root {
  background:
    linear-gradient(180deg, #fbfffb 0%, #f3fff5 18%, #f8fdff 100%);
  box-shadow: 0 16px 0 rgba(18, 56, 101, 0.18), 0 28px 55px rgba(8, 34, 74, 0.20);
}

.vt-body {
  background:
    radial-gradient(circle at 12% 14%, rgba(88,204,2,.07), transparent 20%),
    radial-gradient(circle at 88% 8%, rgba(28,176,246,.07), transparent 20%),
    linear-gradient(180deg, #fbfffb 0%, #f6fff7 45%, #f8fdff 100%);
}

.vt-tabs {
  background: linear-gradient(180deg, #f1faf0 0%, #ebf7ee 100%);
}

.vt-tab {
  color: #60717a;
}

.vt-tab:hover {
  background: #ffffff;
}

.vt-tab.is-active {
  background: linear-gradient(180deg, #dff8cf 0%, #c9f0b0 100%);
  color: var(--accent-dark);
  box-shadow: 0 4px 0 #b6e09a;
}

.vt-topbar, .vt-qprompt, .vt-artcard, .vt-statcard, .vt-read-card, .vt-panel, .vt-matchcard, .vt-typebox {
  background: rgba(255,255,255,.88);
  backdrop-filter: blur(2px);
}

.vt-supercard {
  background:
    radial-gradient(circle at 88% 14%, rgba(28,176,246,.18), transparent 24%),
    radial-gradient(circle at 12% 86%, rgba(88,204,2,.20), transparent 26%),
    linear-gradient(180deg, #ffffff 0%, #f5fff2 52%, #f3fbff 100%);
  border-color: #c7ecb1;
  border-bottom-color: #9bd85e;
  box-shadow: 0 24px 50px rgba(20,40,80,.10);
  overflow: hidden;
}

.vt-supercard::before {
  content: "";
  position: absolute;
  inset: 0 auto auto 0;
  width: 100%;
  height: 12px;
  background: linear-gradient(90deg, #58cc02 0%, #7ddc3b 32%, #1cb0f6 100%);
}

.vt-supercard::after {
  content: "";
  position: absolute;
  right: -36px;
  top: 68px;
  width: 150px;
  height: 150px;
  border-radius: 50%;
  background: radial-gradient(circle at 35% 35%, rgba(255,255,255,.7), rgba(28,176,246,.15) 55%, rgba(28,176,246,.04) 75%, transparent 76%);
  pointer-events: none;
}

.vt-supercard.is-flipped {
  border-color: #9edc71;
  border-bottom-color: #58a700;
}

.vt-hero-word, .vt-supercard .vt-card-term {
  text-shadow: 0 2px 0 rgba(255,255,255,.9);
}

.vt-card-flipnote {
  background: linear-gradient(180deg, #dff4ff 0%, #ccecff 100%);
  box-shadow: 0 4px 0 #b3dff4;
}

.vt-card-example {
  background: rgba(255,255,255,.55);
  border: 2px dashed #d8e9d5;
  border-radius: 18px;
  padding: 16px 18px;
  margin-top: 18px;
}

.vt-card-example-en {
  background: rgba(244,250,255,.78);
  border-radius: 14px;
  padding: 12px 14px;
  margin-top: 12px;
}

.vt-pack-dot {
  box-shadow: 0 0 0 3px rgba(255,255,255,.8);
}

.vt-btn, .vt-iconbtn, .vt-option, .vt-matchcard, .vt-input, .vt-select, select, textarea {
  border-radius: 16px;
}

.vt-btn-primary, .vt-btn--primary {
  box-shadow: 0 5px 0 #58a700;
}

.vt-mini-notice {
  background: linear-gradient(180deg, #101827 0%, #0b1320 100%);
}


/* Natural B1 reading: keep paragraph breaks and avoid wall-of-text feeling */
.vt-read-text { white-space: pre-wrap; }


/* ===== Sentence Builder + Grammar Click + Answer Practice ===== */
.vt-builder-wrap { max-width: 1050px; margin: 0 auto; }
.vt-builder-card {
  background: rgba(255,255,255,.92);
  border: 2px solid var(--rule);
  border-bottom: 7px solid #d6e8d2;
  border-radius: 28px;
  padding: clamp(18px, 3vw, 34px);
  box-shadow: 0 18px 40px rgba(20,40,80,.07);
}
.vt-builder-prompt {
  background: linear-gradient(180deg, #effaff 0%, #e1f6ff 100%);
  border: 2px solid #c8ecff;
  border-radius: 22px;
  padding: 18px 20px;
  font-size: clamp(20px, 2.4vw, 30px);
  font-weight: 900;
  color: #155b7e;
  margin: 16px 0;
}
.vt-builder-meta { font-size: 13px; font-weight: 900; color: var(--ink-dim); text-transform: uppercase; letter-spacing: .05em; }
.vt-builder-target {
  min-height: 86px;
  background: #fbfffb;
  border: 2px dashed #cfe8c9;
  border-radius: 22px;
  padding: 15px;
  display: flex;
  flex-wrap: wrap;
  align-items: flex-start;
  gap: 9px;
  margin: 16px 0;
}
.vt-builder-bank {
  min-height: 100px;
  background: #ffffff;
  border: 2px solid var(--rule);
  border-radius: 22px;
  padding: 16px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}
.vt-tile {
  border: 2px solid #dce8dc;
  border-bottom: 5px solid #cbdccb;
  background: #fff;
  border-radius: 15px;
  padding: 10px 14px;
  font-weight: 900;
  font-size: 18px;
  cursor: pointer;
  transition: transform .12s ease, background .12s ease, border-color .12s ease;
}
.vt-tile:hover { transform: translateY(-2px); border-color: var(--blue); background: var(--blue-soft); }
.vt-tile:active { transform: translateY(2px); border-bottom-width: 2px; }
.vt-tile.is-selected { background: var(--accent-soft); border-color: var(--accent); border-bottom-color: var(--accent-dark); color: var(--accent-dark); }
.vt-builder-feedback {
  margin-top: 14px;
  padding: 12px 14px;
  border-radius: 16px;
  font-weight: 900;
}
.vt-builder-feedback.ok { background: var(--accent-soft); color: var(--accent-dark); }
.vt-builder-feedback.bad { background: var(--die-soft); color: #b91c1c; }
.vt-grammar-box, .vt-answer-box {
  background: linear-gradient(180deg, #ffffff 0%, #f8fffb 100%);
  border: 2px solid var(--rule);
  border-bottom: 5px solid #dcecdc;
  border-radius: 20px;
  padding: 15px;
  margin: 0 0 14px;
}
.vt-grammar-box h4, .vt-answer-box h4 { margin: 0 0 6px; font-size: 18px; }
.vt-grammar-word { font-size: 26px; font-weight: 900; color: var(--blue-dark); margin: 4px 0 8px; }
.vt-grammar-line { font-size: 14px; font-weight: 800; color: var(--ink-2); margin: 5px 0; }
.vt-grammar-line b { color: var(--ink); }
.vt-grammar-empty { color: var(--ink-dim); font-weight: 800; font-size: 14px; }
.vt-answer-select, .vt-answer-input {
  width: 100%;
  border: 2px solid var(--rule);
  border-radius: 14px;
  padding: 10px 12px;
  font: inherit;
  font-weight: 800;
  margin-top: 8px;
}
.vt-answer-input { min-height: 76px; resize: vertical; }
.vt-answer-feedback {
  margin-top: 10px;
  background: #f8fbff;
  border: 2px solid #dbeafe;
  border-radius: 16px;
  padding: 12px;
  font-weight: 800;
  white-space: pre-wrap;
}
.vt-answer-status { font-size: 13px; font-weight: 900; color: var(--blue-dark); margin-top: 8px; }
.vt-answer-error { color: #b91c1c; }


/* ===== Patch: readable long words + bilingual labels ===== */
.vt-artnoun, .vt-card-term, .vt-hero-word, .vt-qprompt-main {
  max-width: 100%;
  overflow-wrap: anywhere;
  word-break: normal;
  hyphens: auto;
}
.vt-artnoun {
  font-size: clamp(34px, 6.2vw, 72px) !important;
  line-height: 1.02 !important;
  padding: 0 8px;
}
.vt-artcard { overflow: hidden; }
.vt-tab small {
  display: block;
  font-size: 10px;
  line-height: 1;
  margin-top: 2px;
  opacity: .72;
  font-weight: 900;
}
.vt-chip-en {
  font-size: 10px;
  font-weight: 900;
  opacity: .72;
  margin-top: 1px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.vt-chip.is-active .vt-chip-en { color: var(--ink-dim); opacity: 1; }
.vt-mode-subtitle {
  margin: -4px auto 18px;
  text-align: center;
  font-weight: 900;
  color: var(--ink-dim);
  font-size: 15px;
}
.vt-bilingual-note {
  font-size: 13px;
  font-weight: 900;
  color: var(--ink-dim);
  margin-top: 4px;
}
.vt-builder-ai-panel {
  background: linear-gradient(180deg, #f8fdff 0%, #effaff 100%);
  border: 2px solid #c8ecff;
  border-bottom: 5px solid #b5e5ff;
  border-radius: 20px;
  padding: 14px;
  margin-top: 16px;
}
.vt-builder-ai-panel h4 { margin: 0 0 5px; font-size: 17px; }
.vt-builder-ai-panel p { margin: 0 0 10px; color: var(--ink-dim); font-weight: 800; }


/* ===== Front page word search + Groq lookup ===== */
.vt-search-page {
  max-width: 1160px;
  margin: 0 auto;
}
.vt-search-hero {
  background:
    radial-gradient(circle at 88% 10%, rgba(28,176,246,.16), transparent 26%),
    radial-gradient(circle at 8% 92%, rgba(88,204,2,.18), transparent 28%),
    linear-gradient(180deg, #ffffff 0%, #f4fff1 100%);
  border: 2px solid var(--rule);
  border-bottom: 8px solid #cfe7c9;
  border-radius: 30px;
  padding: clamp(20px, 3vw, 34px);
  box-shadow: 0 20px 45px rgba(20,40,80,.08);
}
.vt-search-title {
  margin: 0;
  font-size: clamp(30px, 5vw, 56px);
  line-height: 1;
  letter-spacing: -.04em;
  font-weight: 950;
  color: var(--ink);
}
.vt-search-title span { color: var(--accent-dark); }
.vt-search-copy {
  margin: 10px 0 20px;
  color: var(--ink-dim);
  font-size: 16px;
  font-weight: 800;
  max-width: 780px;
}
.vt-search-grid {
  display: grid;
  grid-template-columns: minmax(220px, 1fr) auto;
  gap: 12px;
  align-items: center;
}
.vt-search-input {
  width: 100%;
  min-height: 62px;
  border: 2px solid var(--rule);
  border-bottom: 5px solid #d8e8d5;
  border-radius: 18px;
  padding: 14px 18px;
  font: 900 22px var(--sans);
  color: var(--ink);
  background: #fff;
  outline: none;
}
.vt-search-input:focus {
  border-color: var(--blue);
  border-bottom-color: var(--blue-dark);
  box-shadow: 0 0 0 5px var(--blue-soft);
}
.vt-search-keyrow {
  display: grid;
  grid-template-columns: minmax(220px, 1fr) auto auto auto;
  gap: 10px;
  align-items: center;
  margin-top: 12px;
}
.vt-search-note {
  margin-top: 12px;
  color: var(--ink-dim);
  font-size: 13px;
  font-weight: 800;
}
.vt-search-results {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(320px, 420px);
  gap: 18px;
  margin-top: 22px;
  align-items: start;
}
.vt-search-panel {
  background: rgba(255,255,255,.9);
  border: 2px solid var(--rule);
  border-radius: 24px;
  padding: 18px;
  box-shadow: var(--shadow);
}
.vt-search-panel h3 {
  margin: 0 0 6px;
  font-size: 22px;
  font-weight: 950;
}
.vt-search-panel p {
  margin: 0 0 12px;
  color: var(--ink-dim);
  font-weight: 800;
}
.vt-search-card {
  border: 2px solid var(--rule-soft);
  border-bottom: 5px solid #e1ecdf;
  background: #fff;
  border-radius: 20px;
  padding: 16px;
  margin-top: 12px;
}
.vt-search-card-title {
  display: flex;
  gap: 10px;
  justify-content: space-between;
  align-items: flex-start;
  font-size: 22px;
  font-weight: 950;
  line-height: 1.18;
}
.vt-search-meta {
  margin-top: 8px;
  display: flex;
  gap: 7px;
  flex-wrap: wrap;
  align-items: center;
  color: var(--ink-dim);
  font-size: 12px;
  font-weight: 900;
}
.vt-search-translation {
  margin-top: 12px;
  font-size: 18px;
  font-weight: 900;
  color: var(--accent-dark);
}
.vt-search-example {
  margin-top: 10px;
  padding: 12px 14px;
  background: var(--surface-2);
  border-radius: 16px;
  font-weight: 750;
  color: var(--ink-2);
}
.vt-search-groq {
  white-space: pre-wrap;
  line-height: 1.55;
  font-size: 15px;
  font-weight: 750;
  color: var(--ink);
  background: linear-gradient(180deg, #f8fdff 0%, #ffffff 100%);
  border: 2px solid var(--blue-soft);
  border-radius: 18px;
  padding: 14px;
  overflow-wrap: anywhere;
}
.vt-search-empty {
  padding: 26px 14px;
  text-align: center;
  color: var(--ink-dim);
  font-weight: 900;
}

/* Organised Groq answer cards */
.vt-search-groq { display: grid; gap: 12px; white-space: normal; background: transparent; border: 0; padding: 0; font-size: inherit; font-weight: inherit; overflow-wrap: normal; }
.vt-groq-intro {
  background: linear-gradient(180deg, #eefaff 0%, #ffffff 100%);
  border: 2px solid var(--blue-soft);
  border-radius: 18px;
  padding: 14px 16px;
  font-size: 16px;
  font-weight: 850;
  line-height: 1.45;
  color: var(--ink);
}
.vt-groq-card {
  background: #fff;
  border: 2px solid var(--rule-soft);
  border-bottom: 5px solid #dfeee1;
  border-radius: 18px;
  padding: 14px 16px;
}
.vt-groq-card.is-primary {
  border-color: var(--accent-soft);
  border-bottom-color: #b6e09a;
  background: linear-gradient(180deg, #fbfff8 0%, #ffffff 100%);
}
.vt-groq-label {
  font-size: 12px;
  letter-spacing: .08em;
  text-transform: uppercase;
  font-weight: 950;
  color: var(--accent-dark);
  margin-bottom: 8px;
}
.vt-groq-chip {
  display: inline-flex;
  align-items: center;
  border-radius: 999px;
  padding: 5px 9px;
  margin-right: 8px;
  background: var(--blue-soft);
  color: var(--blue-dark);
  font-size: 12px;
  font-weight: 950;
}
.vt-groq-list { margin: 0; padding-left: 20px; display: grid; gap: 7px; }
.vt-groq-list li { padding-left: 2px; font-size: 15px; line-height: 1.45; font-weight: 780; }
.vt-groq-text { margin: 0; font-size: 15px; line-height: 1.5; font-weight: 780; color: var(--ink); }
.vt-groq-example-de { font-size: 17px; font-weight: 950; color: var(--ink); line-height: 1.45; }
.vt-groq-example-en { margin-top: 8px; background: var(--surface-2); border-radius: 14px; padding: 10px 12px; color: var(--ink-dim); font-size: 14px; font-weight: 800; line-height: 1.45; }
.vt-groq-mini-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 8px; }
.vt-groq-mini { background: var(--surface-2); border-radius: 14px; padding: 10px 12px; }
.vt-groq-mini b { display: block; color: var(--ink-dim); font-size: 11px; letter-spacing: .06em; text-transform: uppercase; margin-bottom: 3px; }
.vt-groq-mini span { color: var(--ink); font-weight: 900; }
@media (max-width: 520px){ .vt-groq-mini-grid { grid-template-columns: 1fr; } }
@media (max-width: 900px){
  .vt-search-grid,
  .vt-search-keyrow,
  .vt-search-results { grid-template-columns: 1fr; }
}

/* ---- added for the hosted version ---- */
.mw-footer {
  max-width: 1360px;
  margin: 12px auto 4px;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
  justify-content: space-between;
  align-items: center;
  color: rgba(255, 255, 255, 0.82);
  font-size: 13px;
}
.mw-footer-actions { display: flex; flex-wrap: wrap; gap: 4px 14px; }
.mw-link {
  background: none;
  border: 0;
  padding: 0;
  color: inherit;
  font: inherit;
  text-decoration: underline;
  text-underline-offset: 3px;
  cursor: pointer;
}
.mw-link:hover { color: #fff; }
/* With the server providing the AI, the key boxes are not needed. */
.server-ai #groqKeyInput, .server-ai #builderGroqKey, .server-ai #wordSearchGroqKey,
.server-ai .vt-ai-check, .server-ai #groqSaveKey, .server-ai #groqClearKey,
.server-ai [id$="SaveKey"], .server-ai [id$="ClearKey"] { display: none !important; }