/* ===== Screen State Management ===== */
.screen { display: none; }
.screen.active { display: block; }

/* ===== FAQ Accordion ===== */
details summary { cursor: pointer; list-style: none; }
details summary::-webkit-details-marker { display: none; }
details[open] .faq-chevron { transform: rotate(90deg); }

/* ===== Theme Toggle ===== */
.theme-btn { color: #6b7280; }
.theme-btn.active { background: #0d9488; color: #fff; }
.theme-btn:hover:not(.active) { color: #4b5563; background: #f3f4f6; }
.dark .theme-btn:hover:not(.active) { color: #d1d5db; background: #374151; }

/* ===== UI Language Toggle ===== */
.ui-lang-btn { color: #6b7280; }
.ui-lang-btn.active { background: #0d9488; color: #fff; }
.ui-lang-btn:hover:not(.active) { color: #4b5563; background: #f3f4f6; }
.dark .ui-lang-btn:hover:not(.active) { color: #d1d5db; background: #374151; }

/* ===== Drop Zone Active State ===== */
.drop-zone.drag-over { border-color: #0d9488 !important; background: rgba(13, 148, 136, 0.04) !important; }
.dark .drop-zone.drag-over { background: rgba(13, 148, 136, 0.1) !important; }

/* ===== Collapsible ===== */
.collapsible-body { display: none; }
.collapsible.open .collapsible-body { display: block; }
.collapsible.open .collapsible-arrow { transform: rotate(90deg); }

/* ===== Transitions ===== */
.bar-fill { transition: height 0.4s ease; min-height: 3px; }
.progress-fill { transition: width 0.4s ease; }

/* ===== Copy Feedback ===== */
#btn-copy.copy-success {
  animation: copy-pop 0.34s ease;
  box-shadow: 0 10px 28px -14px rgba(13, 148, 136, 0.8);
}

.copy-toast {
  position: fixed;
  top: 20px;
  right: 20px;
  z-index: 80;
  max-width: min(320px, calc(100vw - 32px));
  padding: 10px 14px;
  border-radius: 14px;
  background: rgba(17, 24, 39, 0.94);
  color: #f9fafb;
  border: 1px solid rgba(255, 255, 255, 0.08);
  box-shadow: 0 18px 50px -24px rgba(0, 0, 0, 0.45);
  font-size: 12px;
  font-weight: 600;
  line-height: 1.4;
  pointer-events: none;
  opacity: 0;
  transform: translateY(-8px) scale(0.98);
}

.dark .copy-toast {
  background: rgba(3, 7, 18, 0.96);
  border-color: rgba(45, 212, 191, 0.18);
}

#copy-feedback.copy-visible {
  animation: copy-toast-in 0.28s ease forwards;
}

@keyframes copy-pop {
  0% { transform: scale(1); }
  40% { transform: scale(1.08); }
  100% { transform: scale(1); }
}

@keyframes copy-toast-in {
  0% {
    opacity: 0;
    transform: translateY(-8px) scale(0.98);
  }
  100% {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

@media (prefers-reduced-motion: reduce) {
  #btn-copy.copy-success,
  #copy-feedback.copy-visible {
    animation: none;
  }
}

/* ===== Custom Scrollbar ===== */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: #d1d5db; border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: #9ca3af; }
.dark ::-webkit-scrollbar-thumb { background: #374151; }
.dark ::-webkit-scrollbar-thumb:hover { background: #4b5563; }