/* ====================================================
   LOADING STATES KOMPONENTY - HEJBNI KOSTROU
   
   Bezpečné UX vylepšení - pouze CSS/JS, neovlivňuje backend
   ==================================================== */

/* ====================================================
   1. CSS PROMĚNNÉ
   ==================================================== */

:root {
  --loading-spinner-color: #f57803;
  --loading-spinner-size: 40px;
  --loading-overlay-bg: rgba(255, 255, 255, 0.85);
  --loading-backdrop-bg: rgba(0, 0, 0, 0.3);
  --loading-transition: 0.2s ease-out;
  --skeleton-bg: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
  --skeleton-animation-duration: 1.5s;
}

/* ====================================================
   2. SPINNER KOMPONENTA
   ==================================================== */

.loading-spinner {
  display: inline-block;
  width: var(--loading-spinner-size);
  height: var(--loading-spinner-size);
  border: 4px solid rgba(245, 120, 3, 0.2);
  border-top-color: var(--loading-spinner-color);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

.loading-spinner--small {
  width: 20px;
  height: 20px;
  border-width: 2px;
}

.loading-spinner--large {
  width: 60px;
  height: 60px;
  border-width: 6px;
}

.loading-spinner--white {
  border-color: rgba(255, 255, 255, 0.3);
  border-top-color: white;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

/* ====================================================
   3. LOADING OVERLAY
   ==================================================== */

.loading-overlay {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--loading-overlay-bg);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  z-index: 100;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--loading-transition), visibility var(--loading-transition);
}

.loading-overlay.active {
  opacity: 1;
  visibility: visible;
}

.loading-overlay__text {
  font-size: clamp(0.9rem, 1vw, 1.1rem);
  color: #333;
  font-weight: 500;
}

/* Kontejner s relativní pozicí pro overlay */
.loading-container {
  position: relative;
}

/* ====================================================
   4. FULLSCREEN LOADING (pro navigaci mezi stránkami)
   ==================================================== */

.loading-fullscreen {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: var(--loading-backdrop-bg);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1.5rem;
  z-index: 9999;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--loading-transition), visibility var(--loading-transition);
}

.loading-fullscreen.active {
  opacity: 1;
  visibility: visible;
}

.loading-fullscreen__content {
  background: white;
  padding: 2rem 3rem;
  border-radius: 12px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.2);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
}

.loading-fullscreen__text {
  font-size: clamp(1rem, 1.2vw, 1.3rem);
  color: #333;
  font-weight: 600;
}

/* ====================================================
   5. BUTTON LOADING STATE
   ==================================================== */

.btn-loading {
  position: relative;
  pointer-events: none;
  opacity: 0.7;
}

.btn-loading::after {
  content: '';
  position: absolute;
  width: 16px;
  height: 16px;
  top: 50%;
  left: 50%;
  margin-top: -8px;
  margin-left: -8px;
  border: 2px solid transparent;
  border-top-color: currentColor;
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
}

.btn-loading .btn-text {
  visibility: hidden;
}

/* Alternativa: spinner vedle textu */
.btn-loading-inline {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}

.btn-loading-inline .loading-spinner {
  width: 16px;
  height: 16px;
  border-width: 2px;
}

/* ====================================================
   6. SKELETON LOADING (placeholder pro obsah)
   ==================================================== */

.skeleton {
  background: var(--skeleton-bg);
  background-size: 200% 100%;
  animation: skeleton-shimmer var(--skeleton-animation-duration) infinite;
  border-radius: 4px;
}

.skeleton-text {
  height: 1em;
  margin-bottom: 0.5em;
}

.skeleton-text:last-child {
  width: 80%;
}

.skeleton-title {
  height: 1.5em;
  width: 60%;
  margin-bottom: 1em;
}

.skeleton-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
}

.skeleton-table-row {
  display: flex;
  gap: 1rem;
  margin-bottom: 0.75rem;
}

.skeleton-table-cell {
  height: 2rem;
  flex: 1;
}

@keyframes skeleton-shimmer {
  0% {
    background-position: 200% 0;
  }
  100% {
    background-position: -200% 0;
  }
}

/* ====================================================
   7. PROGRESS BAR
   ==================================================== */

.loading-progress {
  width: 100%;
  max-width: 300px;
  height: 6px;
  background: rgba(245, 120, 3, 0.2);
  border-radius: 3px;
  overflow: hidden;
}

.loading-progress__bar {
  height: 100%;
  background: var(--loading-spinner-color);
  width: 0%;
  transition: width 0.3s ease-out;
}

/* Indeterminate progress */
.loading-progress--indeterminate .loading-progress__bar {
  width: 30%;
  animation: progress-indeterminate 1.5s ease-in-out infinite;
}

@keyframes progress-indeterminate {
  0% {
    transform: translateX(-100%);
  }
  100% {
    transform: translateX(400%);
  }
}

/* ====================================================
   8. TABLE LOADING
   ==================================================== */

.table-loading {
  position: relative;
  min-height: 100px;
}

.table-loading::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--loading-overlay-bg);
  z-index: 10;
}

.table-loading::after {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 40px;
  height: 40px;
  margin: -20px 0 0 -20px;
  border: 4px solid rgba(245, 120, 3, 0.2);
  border-top-color: var(--loading-spinner-color);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  z-index: 11;
}

/* ====================================================
   9. FORM LOADING
   ==================================================== */

.form-loading {
  position: relative;
}

.form-loading fieldset,
.form-loading input,
.form-loading select,
.form-loading textarea,
.form-loading button {
  pointer-events: none;
  opacity: 0.6;
}

/* ====================================================
   10. INLINE LOADING TEXT
   ==================================================== */

.loading-dots::after {
  content: '';
  animation: loading-dots 1.5s infinite;
}

@keyframes loading-dots {
  0%, 20% {
    content: '.';
  }
  40% {
    content: '..';
  }
  60%, 100% {
    content: '...';
  }
}

/* ====================================================
   11. SEARCH LOADING
   ==================================================== */

.search-loading {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1rem;
  color: #666;
  font-size: 0.9rem;
}

/* ====================================================
   12. MOBILE RESPONSIVITA
   ==================================================== */

@media (max-width: 768px) {
  :root {
    --loading-spinner-size: 32px;
  }

  .loading-fullscreen__content {
    padding: 1.5rem 2rem;
    margin: 1rem;
  }

  .loading-progress {
    max-width: 250px;
  }
}

/* ====================================================
   13. REDUCED MOTION (přístupnost)
   ==================================================== */

@media (prefers-reduced-motion: reduce) {
  .loading-spinner,
  .skeleton,
  .loading-progress--indeterminate .loading-progress__bar {
    animation: none;
  }

  .loading-spinner {
    border-style: dashed;
  }

  .skeleton {
    background: #e0e0e0;
  }

  .loading-progress--indeterminate .loading-progress__bar {
    width: 50%;
  }
}