.tab-section-h2 {
  font-size: 1.15rem;
  font-weight: 700;
  margin: 0 0 1rem;
  color: var(--text);
  letter-spacing: -0.02em;
}

.theme-toggle {
  position: absolute;
  top: 1rem;
  right: 1.5rem;
  z-index: 20;
  background: var(--card2);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 6px 10px;
  font-size: 1.1rem;
  line-height: 1;
  cursor: pointer;
  transition: background 0.2s, border-color 0.2s;
}
.theme-toggle:hover {
  background: var(--card);
  border-color: var(--border2);
}
.theme-toggle:focus-visible {
  outline: 2px solid var(--accent, #2563eb);
  outline-offset: 2px;
}

.tab-btn:focus-visible,
.card-btn:focus-visible,
.fq-opt:focus-visible,
.f-opt:focus-visible,
.mc-option:focus-visible,
.calc-inp:focus-visible,
.res-textarea:focus-visible,
.open-textarea:focus-visible,
.flashcard-scene:focus-visible,
.subject-btn:focus-visible,
.reset-all-btn:focus-visible,
.tab-reset-btn:focus-visible,
.back-link:focus-visible,
.btn-check:focus-visible,
.btn-model:focus-visible,
.btn:focus-visible {
  outline: 2px solid var(--accent, #2563eb);
  outline-offset: 2px;
}