.skeleton {
  background: linear-gradient(90deg, rgba(0,0,0,0.06) 25%, rgba(0,0,0,0.10) 37%, rgba(0,0,0,0.06) 63%);
  background-size: 400% 100%; animation: skeleton-shimmer 1.4s ease infinite; border-radius: 0.375rem;
}
@keyframes skeleton-shimmer { 0% { background-position: 100% 50%; } 100% { background-position: 0 50%; } }
:focus-visible { outline: 2px solid #C17F3E; outline-offset: 2px; }
@media (prefers-reduced-motion: reduce) { * { animation-duration: 0.001ms !important; transition-duration: 0.001ms !important; } }

.card-hover { transition: transform 0.15s ease, box-shadow 0.15s ease; }
.card-hover:hover { transform: translateY(-1px); box-shadow: 0 6px 18px -8px rgba(22,48,43,0.15); }

.status-badge { font-family: 'IBM Plex Mono', monospace; font-size: 0.7rem; padding: 0.15rem 0.55rem; border-radius: 9999px; border: 1px solid; white-space: nowrap; }
.status-in_progress { background: rgba(193,127,62,0.08); border-color: rgba(193,127,62,0.3); color: #C17F3E; }
.status-submitted, .status-auto_submitted { background: rgba(22,48,43,0.06); border-color: rgba(22,48,43,0.25); color: #16302B; }
.status-graded { background: rgba(47,111,79,0.1); border-color: rgba(47,111,79,0.4); color: #2F6F4F; }

.modal-backdrop { background: rgba(22,48,43,0.45); }

/* ---- Quiz-taking timer ---- */
.quiz-timer {
  font-family: 'IBM Plex Mono', monospace; font-variant-numeric: tabular-nums;
  font-weight: 600; font-size: 1.1rem; padding: 0.4rem 0.9rem; border-radius: 9999px;
  background: rgba(22,48,43,0.06); color: #16302B; transition: background 0.3s ease, color 0.3s ease;
}
.quiz-timer.is-urgent { background: rgba(162,62,46,0.12); color: #A23E2E; animation: pulse-timer 1s infinite; }
@keyframes pulse-timer { 0%, 100% { opacity: 1; } 50% { opacity: 0.6; } }

/* ---- Question card ---- */
.question-card { background: white; border: 1px solid rgba(42,42,40,0.1); border-radius: 0.75rem; padding: 1.25rem; }
.option-label {
  display: flex; align-items: center; gap: 0.65rem; padding: 0.6rem 0.75rem; border-radius: 0.5rem;
  border: 1px solid rgba(42,42,40,0.12); cursor: pointer; transition: all 0.15s ease;
}
.option-label:hover { border-color: rgba(193,127,62,0.4); background: rgba(193,127,62,0.03); }
.option-label.is-selected { border-color: #C17F3E; background: rgba(193,127,62,0.08); }
.option-label.is-correct { border-color: #2F6F4F; background: rgba(47,111,79,0.08); }
.option-label.is-incorrect { border-color: #A23E2E; background: rgba(162,62,46,0.08); }

.question-nav-dot {
  width: 30px; height: 30px; border-radius: 9999px; display: flex; align-items: center; justify-content: center;
  font-size: 0.75rem; font-family: 'IBM Plex Mono', monospace; border: 1px solid rgba(42,42,40,0.15); cursor: pointer;
}
.question-nav-dot.is-answered { background: rgba(47,111,79,0.12); border-color: rgba(47,111,79,0.4); color: #2F6F4F; }
.question-nav-dot.is-current { border-color: #16302B; border-width: 2px; font-weight: 700; }