/**
 * MiUtils Native Shell Architecture
 * Version: 1.0.0
 * Fixed viewport lock, non-scrolling body, inner scroll containers, header, card grids, buttons, inputs, toasts
 */

/* ==========================================================================
   1. Viewport Lockdown & Base Reset
   ========================================================================== */
*, *::before, *::after {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
  width: 100vw;
  height: 100vh;
  height: 100dvh; /* Dynamic viewport height for modern mobile browsers */
  overflow: hidden; /* BODY NEVER SCROLLS: Native App Contract */
  font-family: var(--mu-font-sans);
  font-size: 16px;
  line-height: 1.5;
  background-color: var(--mu-bg-app);
  color: var(--mu-text-primary);
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  color: var(--mu-primary);
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
}

/* ==========================================================================
   2. Fixed App Header (56px)
   ========================================================================== */
.mu-header {
  height: var(--mu-header-height, 56px);
  min-height: var(--mu-header-height, 56px);
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--mu-space-5);
  background-color: var(--mu-bg-surface);
  border-bottom: 1px solid var(--mu-border-subtle);
  z-index: var(--mu-z-header, 100);
  box-shadow: var(--mu-shadow-xs);
}

.mu-header-brand {
  display: flex;
  align-items: center;
  gap: var(--mu-space-3);
  min-width: 0;
}

.mu-brand-link {
  display: flex;
  align-items: center;
  gap: var(--mu-space-2);
  color: var(--mu-text-primary);
  text-decoration: none;
  font-weight: var(--mu-font-bold);
  font-size: var(--mu-text-lg);
  letter-spacing: -0.02em;
}
.mu-brand-link:hover {
  text-decoration: none;
  color: var(--mu-primary);
}

.mu-brand-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: var(--mu-radius-sm);
  background: var(--mu-primary);
  color: var(--mu-text-on-primary);
  font-size: 15px;
  flex-shrink: 0;
}

.mu-header-subtitle {
  font-size: var(--mu-text-xs);
  color: var(--mu-text-muted);
  font-weight: var(--mu-font-medium);
  padding: 3px 10px;
  background-color: var(--mu-bg-surface-secondary);
  border-radius: var(--mu-radius-pill);
  border: 1px solid var(--mu-border-subtle);
  white-space: nowrap;
}

.mu-back-link {
  display: inline-flex;
  align-items: center;
  gap: var(--mu-space-2);
  color: var(--mu-text-secondary);
  text-decoration: none;
  font-size: var(--mu-text-sm);
  font-weight: var(--mu-font-medium);
  padding: 6px 12px;
  border-radius: var(--mu-radius-sm);
  border: 1px solid var(--mu-border-subtle);
  background: var(--mu-bg-surface);
  transition: all var(--mu-transition-fast);
}
.mu-back-link:hover {
  text-decoration: none;
  color: var(--mu-text-primary);
  background: var(--mu-bg-surface-secondary);
  border-color: var(--mu-border-medium);
}

.mu-header-tool-title {
  font-size: var(--mu-text-base);
  font-weight: var(--mu-font-semibold);
  color: var(--mu-text-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.mu-header-actions {
  display: flex;
  align-items: center;
  gap: var(--mu-space-2);
  flex-shrink: 0;
}

/* ==========================================================================
   3. Workspace & Inner Scroll Panels
   ========================================================================== */
.mu-workspace {
  flex: 1;
  min-height: 0; /* Critical for flex child scroll containers */
  display: flex;
  overflow: hidden;
  position: relative;
  background-color: var(--mu-bg-app);
}

.mu-panel {
  flex: 1;
  height: 100%;
  overflow-y: auto;
  overflow-x: hidden;
  padding: var(--mu-space-6);
  -webkit-overflow-scrolling: touch;
}

/* Scrollbar Styling */
.mu-panel::-webkit-scrollbar,
.mu-scrollable::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}
.mu-panel::-webkit-scrollbar-track,
.mu-scrollable::-webkit-scrollbar-track {
  background: var(--mu-scrollbar-track);
}
.mu-panel::-webkit-scrollbar-thumb,
.mu-scrollable::-webkit-scrollbar-thumb {
  background: var(--mu-scrollbar-thumb);
  border-radius: var(--mu-radius-pill);
}
.mu-panel::-webkit-scrollbar-thumb:hover,
.mu-scrollable::-webkit-scrollbar-thumb:hover {
  background: var(--mu-scrollbar-thumb-hover);
}

/* Container Constraint */
.mu-container {
  width: 100%;
  max-width: 1240px;
  margin: 0 auto;
}

/* ==========================================================================
   4. Buttons & Interactive Controls
   ========================================================================== */
.mu-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--mu-space-2);
  padding: 8px 16px;
  font-family: inherit;
  font-size: var(--mu-text-sm);
  font-weight: var(--mu-font-medium);
  line-height: 1.4;
  border-radius: var(--mu-radius-sm);
  border: 1px solid transparent;
  cursor: pointer;
  background-color: var(--mu-bg-surface-secondary);
  color: var(--mu-text-primary);
  transition: all var(--mu-transition-fast);
  white-space: nowrap;
  user-select: none;
}
.mu-btn:hover {
  background-color: var(--mu-bg-surface-hover);
  text-decoration: none;
}
.mu-btn:active {
  background-color: var(--mu-bg-surface-active);
  transform: translateY(1px);
}
.mu-btn:disabled,
.mu-btn[disabled] {
  opacity: 0.5;
  cursor: not-allowed;
  pointer-events: none;
}

.mu-btn-primary {
  background-color: var(--mu-primary);
  color: var(--mu-text-on-primary);
  border-color: transparent;
}
.mu-btn-primary:hover {
  background-color: var(--mu-primary-hover);
  color: var(--mu-text-on-primary);
}
.mu-btn-primary:active {
  background-color: var(--mu-primary-active);
}

.mu-btn-secondary {
  background-color: var(--mu-bg-surface);
  color: var(--mu-text-primary);
  border-color: var(--mu-border-medium);
}
.mu-btn-secondary:hover {
  background-color: var(--mu-bg-surface-secondary);
  border-color: var(--mu-border-strong);
}

.mu-btn-danger {
  background-color: var(--mu-danger);
  color: var(--mu-text-on-primary);
  border-color: transparent;
}
.mu-btn-danger:hover {
  background-color: var(--mu-danger-hover);
}

.mu-btn-success {
  background-color: var(--mu-success);
  color: var(--mu-text-on-primary);
  border-color: transparent;
}
.mu-btn-success:hover {
  background-color: var(--mu-success-hover);
}

.mu-btn-icon {
  width: 36px;
  height: 36px;
  padding: 0;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--mu-radius-sm);
  background: var(--mu-bg-surface);
  border: 1px solid var(--mu-border-subtle);
  color: var(--mu-text-secondary);
  cursor: pointer;
  transition: all var(--mu-transition-fast);
  font-size: 15px;
}
.mu-btn-icon:hover {
  color: var(--mu-text-primary);
  background: var(--mu-bg-surface-secondary);
  border-color: var(--mu-border-medium);
}
.mu-btn-icon:active {
  transform: translateY(1px);
}

.mu-btn-sm {
  padding: 4px 10px;
  font-size: var(--mu-text-xs);
  height: 28px;
}
.mu-btn-lg {
  padding: 12px 24px;
  font-size: var(--mu-text-base);
  font-weight: var(--mu-font-semibold);
}

/* ==========================================================================
   5. Form Controls & Inputs
   ========================================================================== */
.mu-form-group {
  margin-bottom: var(--mu-space-4);
  display: flex;
  flex-direction: column;
}

.mu-label {
  font-size: var(--mu-text-sm);
  font-weight: var(--mu-font-semibold);
  color: var(--mu-text-secondary);
  margin-bottom: var(--mu-space-1);
}

.mu-input,
.mu-select,
.mu-textarea {
  width: 100%;
  font-family: inherit;
  font-size: var(--mu-text-sm);
  color: var(--mu-text-primary);
  background-color: var(--mu-bg-surface);
  border: 1px solid var(--mu-border-medium);
  border-radius: var(--mu-radius-sm);
  padding: 8px 12px;
  outline: none;
  transition: border-color var(--mu-transition-fast), box-shadow var(--mu-transition-fast);
}
.mu-input:focus,
.mu-select:focus,
.mu-textarea:focus {
  border-color: var(--mu-border-focus);
  box-shadow: 0 0 0 3px var(--mu-primary-subtle);
}
.mu-input::placeholder,
.mu-textarea::placeholder {
  color: var(--mu-text-muted);
}
.mu-input:disabled,
.mu-select:disabled,
.mu-textarea:disabled {
  background-color: var(--mu-bg-surface-secondary);
  color: var(--mu-text-muted);
  cursor: not-allowed;
}

.mu-input-mono,
.mu-textarea-mono {
  font-family: var(--mu-font-mono);
}

.mu-textarea {
  min-height: 100px;
  resize: vertical;
}

.mu-input-group {
  display: flex;
  align-items: stretch;
  position: relative;
}
.mu-input-group .mu-input {
  border-radius: var(--mu-radius-sm);
}

/* ==========================================================================
   6. Search Bar & Shortcut Badges
   ========================================================================== */
.mu-search-bar {
  position: relative;
  display: flex;
  align-items: center;
  width: 100%;
}

.mu-search-icon {
  position: absolute;
  left: 14px;
  color: var(--mu-text-muted);
  font-size: 15px;
  pointer-events: none;
}

.mu-search-input {
  width: 100%;
  height: 46px;
  padding: 10px 90px 10px 42px;
  font-size: var(--mu-text-base);
  background-color: var(--mu-bg-surface);
  border: 1px solid var(--mu-border-medium);
  border-radius: var(--mu-radius-md);
  color: var(--mu-text-primary);
  outline: none;
  box-shadow: var(--mu-shadow-xs);
  transition: all var(--mu-transition-fast);
}
.mu-search-input:focus {
  border-color: var(--mu-border-focus);
  box-shadow: 0 0 0 3px var(--mu-primary-subtle), var(--mu-shadow-sm);
}
.mu-search-input::placeholder {
  color: var(--mu-text-muted);
}

.mu-search-actions {
  position: absolute;
  right: 12px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.mu-search-clear {
  display: none;
  background: transparent;
  border: none;
  color: var(--mu-text-muted);
  cursor: pointer;
  padding: 4px;
  font-size: 14px;
  border-radius: 4px;
}
.mu-search-clear:hover {
  color: var(--mu-text-primary);
}

.mu-kbd-shortcut {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 2px 7px;
  font-family: var(--mu-font-mono);
  font-size: var(--mu-text-xs);
  color: var(--mu-text-muted);
  background-color: var(--mu-bg-surface-secondary);
  border: 1px solid var(--mu-border-subtle);
  border-radius: var(--mu-radius-xs);
  pointer-events: none;
  user-select: none;
}

/* ==========================================================================
   7. Category Filter Pills
   ========================================================================== */
.mu-filter-pills {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--mu-space-2);
  margin-top: var(--mu-space-4);
  margin-bottom: var(--mu-space-5);
}

.mu-pill-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  font-size: var(--mu-text-xs);
  font-weight: var(--mu-font-medium);
  border-radius: var(--mu-radius-pill);
  border: 1px solid var(--mu-border-subtle);
  background-color: var(--mu-bg-surface);
  color: var(--mu-text-secondary);
  cursor: pointer;
  transition: all var(--mu-transition-fast);
  user-select: none;
}
.mu-pill-btn:hover {
  background-color: var(--mu-bg-surface-secondary);
  color: var(--mu-text-primary);
  border-color: var(--mu-border-medium);
}
.mu-pill-btn.active {
  background-color: var(--mu-primary);
  color: var(--mu-text-on-primary);
  border-color: var(--mu-primary);
  box-shadow: var(--mu-shadow-xs);
}
.mu-pill-btn.active .mu-pill-count {
  background-color: rgba(255, 255, 255, 0.25);
  color: var(--mu-text-on-primary);
}

.mu-pill-count {
  font-size: 11px;
  font-weight: var(--mu-font-semibold);
  padding: 1px 6px;
  border-radius: var(--mu-radius-pill);
  background-color: var(--mu-bg-surface-secondary);
  color: var(--mu-text-muted);
  transition: all var(--mu-transition-fast);
}

/* ==========================================================================
   8. Tool Card Grid & Tool Cards
   ========================================================================== */
.mu-card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--mu-space-4);
}

.mu-tool-card {
  position: relative;
  display: flex;
  flex-direction: column;
  background-color: var(--mu-bg-surface);
  border: 1px solid var(--mu-border-subtle);
  border-radius: var(--mu-radius-md);
  padding: var(--mu-space-5);
  box-shadow: var(--mu-shadow-xs);
  transition: border-color var(--mu-transition-fast), box-shadow var(--mu-transition-fast), transform var(--mu-transition-fast);
  overflow: hidden;
  text-decoration: none;
  color: inherit;
}
.mu-tool-card:hover {
  border-color: var(--mu-border-medium);
  box-shadow: var(--mu-shadow-md);
  transform: translateY(-2px);
  text-decoration: none;
}

.mu-tool-card-top {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  margin-bottom: var(--mu-space-3);
}

.mu-tool-icon {
  width: 44px;
  height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--mu-radius-sm);
  background-color: var(--mu-primary-subtle);
  color: var(--mu-primary);
  font-size: 20px;
  flex-shrink: 0;
  transition: all var(--mu-transition-fast);
}
.mu-tool-card:hover .mu-tool-icon {
  background-color: var(--mu-primary);
  color: var(--mu-text-on-primary);
}

.mu-tool-category-badge {
  font-size: 11px;
  font-weight: var(--mu-font-semibold);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--mu-text-secondary);
  background-color: var(--mu-bg-surface-secondary);
  padding: 3px 8px;
  border-radius: var(--mu-radius-pill);
  border: 1px solid var(--mu-border-subtle);
}

.mu-tool-title {
  margin: 0 0 var(--mu-space-2) 0;
  font-size: var(--mu-text-base);
  font-weight: var(--mu-font-bold);
  color: var(--mu-text-primary);
  letter-spacing: -0.01em;
}

.mu-tool-desc {
  margin: 0 0 var(--mu-space-4) 0;
  font-size: var(--mu-text-xs);
  color: var(--mu-text-secondary);
  line-height: 1.5;
  flex: 1; /* Pushes bottom tags down */
}

.mu-tool-tags {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: auto;
  padding-top: var(--mu-space-3);
  border-top: 1px solid var(--mu-border-subtle);
}

.mu-tag {
  font-size: 11px;
  font-weight: var(--mu-font-medium);
  color: var(--mu-text-secondary);
  background-color: var(--mu-bg-surface-secondary);
  padding: 2px 8px;
  border-radius: var(--mu-radius-xs);
}

.mu-tool-launch-arrow {
  margin-left: auto;
  font-size: 13px;
  color: var(--mu-primary);
  transition: transform var(--mu-transition-fast);
}
.mu-tool-card:hover .mu-tool-launch-arrow {
  transform: translateX(3px);
}

/* ==========================================================================
   9. Badges & Status Chips
   ========================================================================== */
.mu-badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 3px 8px;
  font-size: var(--mu-text-xs);
  font-weight: var(--mu-font-medium);
  border-radius: var(--mu-radius-xs);
  border: 1px solid var(--mu-border-subtle);
  background-color: var(--mu-bg-surface-secondary);
  color: var(--mu-text-secondary);
}

.mu-badge-success {
  background-color: var(--mu-success-subtle);
  color: var(--mu-success);
  border-color: var(--mu-success-border);
}
.mu-badge-warning {
  background-color: var(--mu-warning-subtle);
  color: var(--mu-warning);
  border-color: var(--mu-warning-border);
}
.mu-badge-danger {
  background-color: var(--mu-danger-subtle);
  color: var(--mu-danger);
  border-color: var(--mu-danger-border);
}
.mu-badge-primary {
  background-color: var(--mu-primary-subtle);
  color: var(--mu-primary);
  border-color: var(--mu-primary-subtle-border);
}

/* ==========================================================================
   10. Toast Notification System
   ========================================================================== */
.mu-toast-container {
  position: fixed;
  bottom: 24px;
  right: 24px;
  z-index: var(--mu-z-toast, 400);
  display: flex;
  flex-direction: column-reverse;
  gap: var(--mu-space-2);
  pointer-events: none;
}

.mu-toast {
  pointer-events: auto;
  min-width: 260px;
  max-width: 400px;
  padding: 12px 16px;
  background-color: var(--mu-bg-surface);
  color: var(--mu-text-primary);
  border: 1px solid var(--mu-border-subtle);
  border-radius: var(--mu-radius-md);
  box-shadow: var(--mu-shadow-lg);
  display: flex;
  align-items: center;
  gap: var(--mu-space-3);
  font-size: var(--mu-text-sm);
  font-weight: var(--mu-font-medium);
  animation: muToastIn 200ms cubic-bezier(0.16, 1, 0.3, 1) forwards;
  transition: opacity 150ms ease, transform 150ms ease;
}

.mu-toast.mu-toast-exit {
  opacity: 0;
  transform: translateY(10px) scale(0.96);
}

.mu-toast-icon {
  font-size: 16px;
  flex-shrink: 0;
}
.mu-toast-success .mu-toast-icon { color: var(--mu-success); }
.mu-toast-error .mu-toast-icon { color: var(--mu-danger); }
.mu-toast-warning .mu-toast-icon { color: var(--mu-warning); }
.mu-toast-info .mu-toast-icon { color: var(--mu-primary); }

.mu-toast-content {
  flex: 1;
}

@keyframes muToastIn {
  from {
    opacity: 0;
    transform: translateY(16px) scale(0.96);
  }
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

/* ==========================================================================
   11. Empty State Component
   ========================================================================== */
.mu-empty-state {
  display: none;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 60px 20px;
  text-align: center;
  background-color: var(--mu-bg-surface);
  border: 1px dashed var(--mu-border-medium);
  border-radius: var(--mu-radius-lg);
  margin-top: var(--mu-space-4);
}
.mu-empty-state.visible {
  display: flex;
}

.mu-empty-icon {
  width: 56px;
  height: 56px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background-color: var(--mu-bg-surface-secondary);
  color: var(--mu-text-muted);
  font-size: 24px;
  margin-bottom: var(--mu-space-3);
}

.mu-empty-title {
  margin: 0 0 var(--mu-space-1) 0;
  font-size: var(--mu-text-base);
  font-weight: var(--mu-font-semibold);
  color: var(--mu-text-primary);
}

.mu-empty-desc {
  margin: 0 0 var(--mu-space-4) 0;
  font-size: var(--mu-text-sm);
  color: var(--mu-text-secondary);
  max-width: 360px;
}

/* ==========================================================================
   12. Hub Hero, Recent Tools & Footer
   ========================================================================== */
.mu-hub-hero {
  padding: var(--mu-space-2) 0 var(--mu-space-4) 0;
}

.mu-hub-hero-title {
  font-size: 1.75rem;
  font-weight: var(--mu-font-bold);
  color: var(--mu-text-primary);
  margin: 0 0 var(--mu-space-1) 0;
  letter-spacing: -0.02em;
}

.mu-hub-hero-desc {
  font-size: var(--mu-text-sm);
  color: var(--mu-text-secondary);
  margin: 0;
  max-width: 640px;
  line-height: 1.5;
}

.mu-recent-section {
  margin-top: var(--mu-space-4);
  margin-bottom: var(--mu-space-4);
  padding: var(--mu-space-3) var(--mu-space-4);
  background-color: var(--mu-bg-surface);
  border: 1px solid var(--mu-border-subtle);
  border-radius: var(--mu-radius-md);
}

.mu-recent-header {
  font-size: var(--mu-text-xs);
  font-weight: var(--mu-font-semibold);
  text-transform: uppercase;
  color: var(--mu-text-muted);
  margin-bottom: var(--mu-space-2);
  display: flex;
  align-items: center;
  gap: var(--mu-space-2);
  letter-spacing: 0.04em;
}

.mu-recent-list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--mu-space-2);
}

.mu-recent-item {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 12px;
  background-color: var(--mu-bg-surface-secondary);
  border: 1px solid var(--mu-border-subtle);
  border-radius: var(--mu-radius-sm);
  font-size: var(--mu-text-xs);
  font-weight: var(--mu-font-medium);
  color: var(--mu-text-primary);
  text-decoration: none;
  transition: all var(--mu-transition-fast);
}
.mu-recent-item:hover {
  background-color: var(--mu-bg-surface-hover);
  border-color: var(--mu-border-medium);
  text-decoration: none;
  transform: translateY(-1px);
}

.mu-recent-icon {
  color: var(--mu-primary);
  font-size: 13px;
}

.mu-recent-arrow {
  color: var(--mu-text-muted);
  font-size: 10px;
  margin-left: 2px;
}

.mu-hub-footer {
  margin-top: var(--mu-space-8);
  padding: var(--mu-space-5) 0 var(--mu-space-4) 0;
  border-top: 1px solid var(--mu-border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: var(--mu-text-xs);
  color: var(--mu-text-muted);
  flex-wrap: wrap;
  gap: var(--mu-space-3);
}

/* ==========================================================================
   13. Responsive Breakpoints (Down to 375px)
   ========================================================================== */
@media (max-width: 768px) {
  .mu-header {
    padding: 0 var(--mu-space-3);
  }

  .mu-header-subtitle {
    display: none; /* Conserve space on mobile */
  }

  .mu-panel {
    padding: var(--mu-space-4);
  }

  .mu-card-grid {
    grid-template-columns: 1fr;
    gap: var(--mu-space-3);
  }

  .mu-search-input {
    font-size: var(--mu-text-sm);
    height: 42px;
    padding-right: 75px;
  }

  .mu-toast-container {
    bottom: 12px;
    right: 12px;
    left: 12px;
  }
  .mu-toast {
    min-width: unset;
    width: 100%;
  }
}

@media (max-width: 480px) {
  .mu-header-brand .mu-brand-link span {
    font-size: var(--mu-text-base);
  }
  .mu-panel {
    padding: var(--mu-space-3);
  }
  .mu-pill-btn {
    padding: 5px 10px;
    font-size: 11px;
  }
}