* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --primary: #6366f1;
  --primary-hover: #4f46e5;
  --secondary: #64748b;
  --danger: #ef4444;
  --success: #22c55e;
  --warning: #f59e0b;
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-tertiary: #334155;
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --border-color: #334155;
  --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
}

.app {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* Header */
.header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 2rem;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
}

.header-brand h1 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary);
}

.header-brand .subtitle {
  font-size: 0.75rem;
  color: var(--text-secondary);
  margin-left: 0.5rem;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.625rem 1.25rem;
  border: none;
  border-radius: 0.5rem;
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s;
}

.btn-primary {
  background: var(--primary);
  color: white;
}

.btn-primary:hover {
  background: var(--primary-hover);
}

.btn-secondary {
  background: var(--bg-tertiary);
  color: var(--text-primary);
}

.btn-secondary:hover {
  background: var(--secondary);
}

.btn-danger {
  background: var(--danger);
  color: white;
}

.btn-danger:hover {
  background: #dc2626;
}

.btn-small {
  padding: 0.375rem 0.75rem;
  font-size: 0.875rem;
}

.btn-close {
  background: none;
  border: none;
  color: var(--text-secondary);
  font-size: 1.5rem;
  cursor: pointer;
  line-height: 1;
}

.btn-close:hover {
  color: var(--text-primary);
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

/* Main Content Layout */
.main-content {
  display: flex;
  flex: 1;
}

/* Sidebar */
.sidebar {
  width: 260px;
  background: var(--bg-secondary);
  border-right: 1px solid var(--border-color);
  padding: 1rem;
  overflow-y: auto;
}

.sidebar-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--border-color);
}

.sidebar-header h2 {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.folder-list {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.folder-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.625rem 0.75rem;
  border-radius: 0.5rem;
  cursor: pointer;
  transition: background 0.2s;
}

.folder-item:hover {
  background: var(--bg-tertiary);
}

.folder-item.active {
  background: var(--primary);
  color: white;
}

.folder-icon {
  font-size: 1.125rem;
}

.folder-name {
  flex: 1;
  font-size: 0.875rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.folder-item.subfolder {
  padding-left: 2rem;
}

.folder-actions {
  display: none;
  gap: 0.25rem;
}

.folder-item:hover .folder-actions {
  display: flex;
}

.folder-action-btn {
  background: none;
  border: none;
  color: var(--text-secondary);
  cursor: pointer;
  padding: 0.25rem;
  font-size: 0.75rem;
}

.folder-action-btn:hover {
  color: var(--text-primary);
}

/* Content Area */
.content {
  flex: 1;
  padding: 1.5rem;
  overflow-y: auto;
}

.content-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
  gap: 1rem;
}

.breadcrumb {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--text-primary);
}

.content-controls {
  display: flex;
  gap: 0.75rem;
  align-items: center;
}

.search-box input {
  padding: 0.5rem 1rem;
  border: 1px solid var(--border-color);
  border-radius: 0.5rem;
  background: var(--bg-secondary);
  color: var(--text-primary);
  font-size: 0.875rem;
  width: 200px;
}

.search-box input:focus {
  outline: none;
  border-color: var(--primary);
}

.filter-controls select {
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--border-color);
  border-radius: 0.5rem;
  background: var(--bg-secondary);
  color: var(--text-primary);
  font-size: 0.875rem;
  cursor: pointer;
}

.filter-controls select:focus {
  outline: none;
  border-color: var(--primary);
}

/* Files Grid */
.files-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: 1rem;
}

.file-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 0.75rem;
  overflow: hidden;
  cursor: pointer;
  transition: all 0.2s;
}

.file-card:hover {
  border-color: var(--primary);
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

.file-thumbnail {
  height: 140px;
  background: var(--bg-tertiary);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.file-thumbnail img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.file-thumbnail .file-icon {
  font-size: 3rem;
  color: var(--text-secondary);
}

.file-info {
  padding: 0.75rem;
}

.file-name {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  margin-bottom: 0.25rem;
}

.file-meta {
  font-size: 0.75rem;
  color: var(--text-secondary);
}

/* Empty State */
.empty-state {
  grid-column: 1 / -1;
  text-align: center;
  padding: 4rem 2rem;
  color: var(--text-secondary);
}

.empty-icon {
  font-size: 4rem;
  margin-bottom: 1rem;
  opacity: 0.5;
}

.text-muted {
  color: var(--text-secondary);
  font-size: 0.875rem;
}

/* Pagination */
.pagination {
  display: flex;
  justify-content: center;
  gap: 0.5rem;
  margin-top: 2rem;
}

.pagination button {
  padding: 0.5rem 1rem;
  border: 1px solid var(--border-color);
  border-radius: 0.375rem;
  background: var(--bg-secondary);
  color: var(--text-primary);
  cursor: pointer;
}

.pagination button:hover:not(:disabled) {
  background: var(--bg-tertiary);
}

.pagination button.active {
  background: var(--primary);
  border-color: var(--primary);
}

.pagination button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

/* Modal */
.modal {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.7);
  z-index: 1000;
  align-items: center;
  justify-content: center;
}

.modal.active {
  display: flex;
}

.modal-content {
  background: var(--bg-secondary);
  border-radius: 1rem;
  width: 90%;
  max-width: 600px;
  max-height: 90vh;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.modal-content.modal-small {
  max-width: 400px;
}

.modal-content.modal-large {
  max-width: 900px;
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 1.5rem;
  border-bottom: 1px solid var(--border-color);
}

.modal-header h3 {
  font-size: 1.125rem;
  font-weight: 600;
}

.modal-body {
  padding: 1.5rem;
  overflow-y: auto;
  flex: 1;
}

.modal-footer {
  display: flex;
  justify-content: flex-end;
  gap: 0.75rem;
  padding: 1rem 1.5rem;
  border-top: 1px solid var(--border-color);
}

/* Upload Area */
.upload-area {
  border: 2px dashed var(--border-color);
  border-radius: 0.75rem;
  padding: 3rem 2rem;
  text-align: center;
  transition: all 0.2s;
}

.upload-area.dragover {
  border-color: var(--primary);
  background: rgba(99, 102, 241, 0.1);
}

.upload-icon {
  font-size: 3rem;
  margin-bottom: 1rem;
  color: var(--text-secondary);
}

.upload-area p {
  margin-bottom: 0.5rem;
}

.upload-folder {
  margin-top: 1.5rem;
  display: flex;
  align-items: center;
  gap: 1rem;
}

.upload-folder label {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.upload-folder select {
  flex: 1;
  padding: 0.5rem;
  border: 1px solid var(--border-color);
  border-radius: 0.5rem;
  background: var(--bg-tertiary);
  color: var(--text-primary);
}

.upload-preview {
  margin-top: 1.5rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.upload-preview-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 0.75rem;
  background: var(--bg-tertiary);
  border-radius: 0.5rem;
  font-size: 0.875rem;
}

.upload-preview-item .remove-file {
  background: none;
  border: none;
  color: var(--text-secondary);
  cursor: pointer;
  font-size: 1rem;
}

.upload-preview-item .remove-file:hover {
  color: var(--danger);
}

/* Form Groups */
.form-group {
  margin-bottom: 1rem;
}

.form-group label {
  display: block;
  margin-bottom: 0.5rem;
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.form-group input,
.form-group select {
  width: 100%;
  padding: 0.625rem 0.75rem;
  border: 1px solid var(--border-color);
  border-radius: 0.5rem;
  background: var(--bg-tertiary);
  color: var(--text-primary);
  font-size: 0.875rem;
}

.form-group input:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--primary);
}

/* Preview Modal */
.preview-body {
  display: flex;
  gap: 1.5rem;
}

.preview-container {
  flex: 1;
  min-height: 300px;
  background: var(--bg-tertiary);
  border-radius: 0.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.preview-container img {
  max-width: 100%;
  max-height: 400px;
  object-fit: contain;
}

.preview-container .doc-preview {
  text-align: center;
  padding: 2rem;
}

.preview-container .doc-preview .icon {
  font-size: 4rem;
  margin-bottom: 1rem;
}

.preview-info {
  width: 250px;
}

.preview-info-item {
  margin-bottom: 1rem;
}

.preview-info-item label {
  display: block;
  font-size: 0.75rem;
  color: var(--text-secondary);
  margin-bottom: 0.25rem;
  text-transform: uppercase;
}

.preview-info-item span {
  font-size: 0.875rem;
  color: var(--text-primary);
  word-break: break-all;
}

/* Context Menu */
.context-menu {
  display: none;
  position: fixed;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 0.5rem;
  padding: 0.5rem 0;
  min-width: 150px;
  z-index: 1001;
  box-shadow: var(--shadow);
}

.context-menu.active {
  display: block;
}

.context-menu-item {
  padding: 0.5rem 1rem;
  font-size: 0.875rem;
  cursor: pointer;
}

.context-menu-item:hover {
  background: var(--bg-tertiary);
}

.context-menu-item[data-action="delete"] {
  color: var(--danger);
}

/* Toast Notifications */
.toast-container {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  z-index: 1002;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.toast {
  padding: 1rem 1.5rem;
  border-radius: 0.5rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow);
  animation: slideIn 0.3s ease;
  max-width: 350px;
}

.toast.success {
  border-color: var(--success);
}

.toast.error {
  border-color: var(--danger);
}

.toast.warning {
  border-color: var(--warning);
}

@keyframes slideIn {
  from {
    transform: translateX(100%);
    opacity: 0;
  }
  to {
    transform: translateX(0);
    opacity: 1;
  }
}

/* Loading Spinner */
.loading {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2rem;
}

.spinner {
  width: 40px;
  height: 40px;
  border: 3px solid var(--border-color);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

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

/* Responsive */
@media (max-width: 768px) {
  .main-content {
    flex-direction: column;
  }

  .sidebar {
    width: 100%;
    border-right: none;
    border-bottom: 1px solid var(--border-color);
    max-height: 200px;
  }

  .content-header {
    flex-direction: column;
    align-items: flex-start;
  }

  .content-controls {
    width: 100%;
    flex-wrap: wrap;
  }

  .search-box {
    width: 100%;
  }

  .search-box input {
    width: 100%;
  }

  .preview-body {
    flex-direction: column;
  }

  .preview-info {
    width: 100%;
  }

  .files-grid {
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  }
}

/* Tags */
.tag-list {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.tag-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 0.75rem;
  border-radius: 0.5rem;
  cursor: pointer;
  transition: background 0.2s;
}

.tag-item:hover {
  background: var(--bg-tertiary);
}

.tag-item.active {
  background: var(--bg-tertiary);
}

.tag-color {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  flex-shrink: 0;
}

.tag-name {
  flex: 1;
  font-size: 0.875rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.tag-count {
  font-size: 0.75rem;
  color: var(--text-secondary);
  background: var(--bg-primary);
  padding: 0.125rem 0.5rem;
  border-radius: 1rem;
}

/* Tag badges on file cards */
.file-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem;
  margin-top: 0.5rem;
}

.tag-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  padding: 0.125rem 0.5rem;
  border-radius: 1rem;
  font-size: 0.625rem;
  color: white;
  max-width: 100%;
}

.tag-badge span {
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* Color picker */
.color-picker {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.color-option {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  cursor: pointer;
  border: 3px solid transparent;
  transition: all 0.2s;
}

.color-option:hover {
  transform: scale(1.1);
}

.color-option.selected {
  border-color: white;
  box-shadow: 0 0 0 2px var(--bg-primary);
}

/* Tag checkboxes in modal */
.tag-checkboxes {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  max-height: 300px;
  overflow-y: auto;
}

.tag-checkbox {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.5rem;
  border-radius: 0.5rem;
  cursor: pointer;
  transition: background 0.2s;
}

.tag-checkbox:hover {
  background: var(--bg-tertiary);
}

.tag-checkbox input {
  width: 18px;
  height: 18px;
  cursor: pointer;
}

.tag-checkbox .tag-color {
  width: 16px;
  height: 16px;
}

.tag-checkbox .tag-label {
  flex: 1;
  font-size: 0.875rem;
}

/* Preview tags section */
.preview-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.375rem;
  margin-top: 0.5rem;
}

.preview-tags .tag-badge {
  font-size: 0.75rem;
  padding: 0.25rem 0.625rem;
}

/* Empty tag list */
.tag-list-empty {
  padding: 1rem;
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.75rem;
}