body {
  --bg: #09090b;
  --panel: rgba(24, 24, 27, 0.74);
  --panel-strong: rgba(39, 39, 42, 0.86);
  --border: rgba(255,255,255,0.12);
  --text: #fafafa;
  --muted: #a1a1aa;
  --primary: #00bc7d;
  --primary-dark: #0d542b;
  margin: 0;
  background:
    radial-gradient(circle at 50% -8%, rgba(0,188,125,0.2), transparent 34rem),
    radial-gradient(circle at 18% 24%, rgba(20,71,230,0.12), transparent 28rem),
    var(--bg);
  color: var(--text);
  font-family: "Plus Jakarta Sans", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

.cluster-header {
  background: rgba(9,9,11,0.88);
  backdrop-filter: blur(18px);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 20;
}

.cluster-nav,
.cluster-shell {
  max-width: 1180px;
  margin: 0 auto;
  padding: 0 24px;
}

.cluster-nav {
  align-items: center;
  display: flex;
  justify-content: space-between;
  min-height: 64px;
}

.cluster-logo {
  color: var(--text);
  font-size: 20px;
  font-weight: 900;
  text-decoration: none;
}

.cluster-links {
  display: flex;
  gap: 22px;
}

.cluster-links a {
  color: var(--muted);
  font-weight: 800;
  text-decoration: none;
}

.cluster-links a:hover {
  color: var(--text);
}

.cluster-hero {
  align-items: start;
  display: grid;
  gap: clamp(28px, 5vw, 64px);
  grid-template-columns: minmax(0, 1fr) minmax(320px, 420px);
  padding: 68px 24px 42px;
}

.cluster-hero > div:first-child {
  max-width: 760px;
  padding-top: 16px;
}

.cluster-kicker {
  color: var(--primary);
  font-size: 0.78rem;
  font-weight: 900;
  letter-spacing: 0.08em;
  margin: 0 0 14px;
  text-transform: uppercase;
}

.cluster-hero h1 {
  color: var(--text);
  font-size: clamp(3.2rem, 7vw, 6.8rem);
  font-weight: 900;
  letter-spacing: 0;
  line-height: 0.95;
  margin: 0;
  max-width: 820px;
}

.cluster-lead {
  color: var(--muted);
  font-size: 1.08rem;
  line-height: 1.75;
  margin: 24px 0 0;
  max-width: 680px;
}

.cluster-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 30px;
}

.cluster-button {
  align-items: center;
  background: var(--primary);
  border: 1px solid var(--primary);
  border-radius: 12px;
  box-shadow: 0 0 20px rgba(0,188,125,0.22);
  color: var(--primary-dark);
  display: inline-flex;
  font-weight: 900;
  min-height: 44px;
  padding: 0 18px;
  text-decoration: none;
}

.cluster-button.secondary {
  background: rgba(255,255,255,0.05);
  border-color: var(--border);
  box-shadow: none;
  color: var(--text);
}

.cluster-media,
.cluster-quiz-panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 16px;
  box-shadow: 0 24px 80px rgba(0,0,0,0.28);
}

.cluster-media {
  min-height: 300px;
  object-fit: cover;
  width: 100%;
}

.cluster-quiz-panel {
  margin-top: 8px;
  padding: 22px;
  position: sticky;
  top: 92px;
}

.cluster-section {
  padding: 32px 24px;
}

.cluster-section h2 {
  color: var(--text);
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  font-weight: 900;
  line-height: 1.1;
  margin: 0 0 16px;
}

.cluster-section > p {
  color: var(--muted);
  font-size: 1rem;
  line-height: 1.7;
  margin: 0 0 24px;
  max-width: 760px;
}

.cluster-grid {
  display: grid;
  gap: 14px;
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.verb-grid {
  grid-template-columns: repeat(5, minmax(0, 1fr));
}

.cluster-card,
.cluster-note,
.tense-table,
.example-list li,
.vt-public-quiz-card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  box-shadow: 0 16px 48px rgba(0,0,0,0.18);
}

.cluster-card {
  color: var(--text);
  display: block;
  padding: 18px;
  text-decoration: none;
  transition: border-color 0.2s ease, transform 0.2s ease;
}

.cluster-card:hover {
  border-color: rgba(0,188,125,0.5);
  transform: translateY(-2px);
}

.cluster-card strong {
  color: var(--primary);
  display: block;
  font-size: 18px;
  margin-bottom: 8px;
}

.cluster-card span,
.cluster-note,
.example-list li,
.cluster-footer,
.vt-public-quiz-subtitle,
.vt-public-quiz-prompt,
.vt-public-quiz-count,
.vt-public-quiz-feedback,
.vt-public-quiz-score span {
  color: var(--muted);
}

.cluster-note {
  line-height: 1.7;
  padding: 18px;
}

.tense-table {
  border-collapse: separate;
  border-spacing: 0;
  overflow: hidden;
  width: 100%;
}

.tense-table th,
.tense-table td {
  border-bottom: 1px solid var(--border);
  padding: 14px 16px;
  text-align: left;
}

.tense-table th {
  background: rgba(255,255,255,0.06);
  color: var(--text);
}

.tense-table td {
  color: var(--muted);
}

.example-list {
  display: grid;
  gap: 12px;
  margin: 22px 0 0;
  padding: 0;
}

.example-list li {
  border-left: 4px solid var(--primary);
  list-style: none;
  padding: 14px 16px;
}

.cluster-footer {
  border-top: 1px solid var(--border);
  margin-top: 44px;
  padding: 28px 24px;
  text-align: center;
}

.cluster-footer a {
  color: var(--primary);
}

.vt-public-quiz {
  margin: 0;
}

.vt-public-quiz-card {
  background: transparent;
  border: 0;
  box-shadow: none;
  padding: 0;
}

.vt-public-quiz-top {
  align-items: flex-start;
  display: flex;
  gap: 18px;
  justify-content: space-between;
}

.vt-public-quiz-kicker {
  color: var(--primary);
  font-size: 12px;
  font-weight: 900;
  letter-spacing: 0.08em;
  margin: 0 0 8px;
  text-transform: uppercase;
}

.vt-public-quiz-title,
.vt-public-quiz-question h3,
.vt-public-quiz-done h3 {
  color: var(--text);
  line-height: 1.2;
  margin: 0;
}

.vt-public-quiz-title {
  font-size: 1.45rem;
}

.vt-public-quiz-score {
  background: rgba(0,188,125,0.1);
  border: 1px solid rgba(0,188,125,0.24);
  border-radius: 10px;
  color: #d1fae5;
  min-width: 82px;
  padding: 10px;
  text-align: center;
}

.vt-public-quiz-score strong {
  display: block;
  font-size: 24px;
}

.vt-public-quiz-progress {
  background: rgba(255,255,255,0.08);
  border-radius: 999px;
  height: 8px;
  margin: 18px 0;
  overflow: hidden;
}

.vt-public-quiz-progress span {
  background: var(--primary);
  display: block;
  height: 100%;
}

.vt-public-quiz-choices {
  display: grid;
  gap: 10px;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.vt-public-quiz-choices button,
.vt-public-quiz-actions a,
.vt-public-quiz-actions button {
  border-radius: 8px;
  font-weight: 800;
  min-height: 40px;
  padding: 8px 10px;
}

.vt-public-quiz-choices button {
  background: rgba(255,255,255,0.05);
  border: 1px solid var(--border);
  color: var(--text);
}

.vt-public-quiz-choices button.is-correct {
  background: rgba(0,188,125,0.18);
  border-color: rgba(0,188,125,0.65);
  color: #d1fae5;
}

.vt-public-quiz-choices button.is-wrong {
  background: rgba(255,32,86,0.14);
  border-color: rgba(255,32,86,0.55);
  color: #ffe4e6;
}

.vt-public-quiz-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 18px;
}

.vt-public-quiz-actions a,
.vt-public-quiz-actions button {
  align-items: center;
  border: 1px solid var(--border);
  display: inline-flex;
  justify-content: center;
  padding: 0 16px;
  text-decoration: none;
}

.vt-public-quiz-actions a {
  background: var(--primary);
  border-color: var(--primary);
  color: var(--primary-dark);
}

.vt-public-quiz-actions a.secondary,
.vt-public-quiz-actions button {
  background: rgba(255,255,255,0.05);
  color: var(--text);
}

@media (max-width: 880px) {
  .cluster-hero,
  .cluster-grid,
  .verb-grid {
    grid-template-columns: 1fr;
  }

  .cluster-links {
    display: none;
  }

  .cluster-media {
    min-height: 220px;
  }

  .cluster-quiz-panel {
    position: static;
  }

  .vt-public-quiz-top,
  .vt-public-quiz-actions {
    flex-direction: column;
  }

  .vt-public-quiz-score {
    width: 100%;
  }

  .vt-public-quiz-choices {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 640px) {
  .cluster-hero {
    padding-top: 42px;
  }

  .cluster-hero h1 {
    font-size: 3.5rem;
  }
}