:root {
  /* Color Palette - Dark Theme */
  --bg-primary: #0f1117;
  --bg-secondary: #1a1d27;
  --bg-tertiary: #252836;
  --bg-hover: #2d3044;
  
  --text-primary: #e4e6f0;
  --text-secondary: #9395a8;
  --text-muted: #5d5f72;
  
  --accent-primary: #6c5ce7;
  --accent-secondary: #a29bfe;
  --accent-glow: rgba(108, 92, 231, 0.3);
  
  --success: #00cec9;
  --warning: #fdcb6e;
  --error: #ff6b6b;
  
  --border-color: #2d3044;
  --border-radius: 12px;
  --border-radius-sm: 8px;
  
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.4);
  
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
}

/* Reset & Base */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.6;
}

/* Header */
.app-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 24px;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-left {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.app-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -0.5px;
}

.logo-icon {
  font-size: 1.8rem;
}

.logo-text {
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.app-subtitle {
  font-size: 0.75rem;
  color: var(--text-muted);
  letter-spacing: 0.5px;
  text-transform: uppercase;
}

.header-right {
  display: flex;
  align-items: center;
  gap: 20px;
}

.connection-status {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.status-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--error);
  transition: background var(--transition-fast);
}

.status-dot.connected {
  background: var(--success);
  box-shadow: 0 0 8px rgba(0, 206, 201, 0.5);
}

.status-dot.disconnected {
  background: var(--error);
}

.client-count {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.85rem;
  color: var(--text-secondary);
  background: var(--bg-tertiary);
  padding: 6px 12px;
  border-radius: 20px;
}

.count-icon {
  font-size: 1rem;
}

/* Main Content */
.app-main {
  max-width: 900px;
  margin: 0 auto;
  padding: 24px 16px;
}

/* Drop Zone */
.drop-zone-section {
  margin-bottom: 24px;
}

.drop-zone {
  border: 2px dashed var(--border-color);
  border-radius: var(--border-radius);
  padding: 48px 24px;
  text-align: center;
  cursor: pointer;
  transition: all var(--transition-normal);
  background: var(--bg-secondary);
}

.drop-zone:hover,
.drop-zone.drag-over {
  border-color: var(--accent-primary);
  background: var(--bg-tertiary);
  box-shadow: 0 0 20px var(--accent-glow);
}

.drop-zone-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.drop-icon {
  font-size: 3rem;
  margin-bottom: 8px;
}

.drop-title {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-primary);
}

.drop-subtitle {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 8px;
}

/* Tabs */
.tabs-container {
  display: flex;
  gap: 4px;
  background: var(--bg-secondary);
  padding: 4px;
  border-radius: var(--border-radius);
  margin-bottom: 20px;
  border: 1px solid var(--border-color);
}

.tab {
  flex: 1;
  padding: 10px 16px;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  border-radius: var(--border-radius-sm);
  transition: all var(--transition-fast);
}

.tab:hover {
  color: var(--text-primary);
  background: var(--bg-hover);
}

.tab.active {
  color: var(--text-primary);
  background: var(--accent-primary);
  box-shadow: var(--shadow-sm);
}

/* Tab Content */
.tab-content {
  display: none;
  animation: fadeIn 0.2s ease;
}

.tab-content.active {
  display: block;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Clipboard Section */
.clipboard-section {
  background: var(--bg-secondary);
  border-radius: var(--border-radius);
  border: 1px solid var(--border-color);
  overflow: hidden;
}

.clipboard-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 20px;
  border-bottom: 1px solid var(--border-color);
}

.clipboard-header h3 {
  font-size: 1rem;
  font-weight: 600;
}

.clipboard-status {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.clipboard-body {
  padding: 16px 20px;
}

#clipboardText {
  width: 100%;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-sm);
  color: var(--text-primary);
  font-family: inherit;
  font-size: 0.95rem;
  padding: 12px 16px;
  resize: vertical;
  transition: border-color var(--transition-fast);
}

#clipboardText:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

.clipboard-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 20px;
  border-top: 1px solid var(--border-color);
}

.clipboard-hint {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* Items Section */
.items-section {
  background: var(--bg-secondary);
  border-radius: var(--border-radius);
  border: 1px solid var(--border-color);
  overflow: hidden;
}

.items-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 20px;
  border-bottom: 1px solid var(--border-color);
}

.items-header h3 {
  font-size: 1rem;
  font-weight: 600;
}

.items-list {
  max-height: 500px;
  overflow-y: auto;
}

.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 48px 24px;
  text-align: center;
}

.empty-icon {
  font-size: 3rem;
  margin-bottom: 12px;
  opacity: 0.5;
}

.empty-state p {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.empty-hint {
  font-size: 0.85rem !important;
  color: var(--text-muted) !important;
  margin-top: 4px;
}

/* Item Card */
.item-card {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 16px 20px;
  border-bottom: 1px solid var(--border-color);
  transition: background var(--transition-fast);
}

.item-card:last-child {
  border-bottom: none;
}

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

.item-icon {
  font-size: 2rem;
  flex-shrink: 0;
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-tertiary);
  border-radius: var(--border-radius-sm);
}

.item-details {
  flex: 1;
  min-width: 0;
}

.item-name {
  font-weight: 600;
  font-size: 0.95rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.item-meta {
  display: flex;
  gap: 12px;
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-top: 4px;
}

.item-actions {
  display: flex;
  gap: 8px;
  flex-shrink: 0;
}

/* Text Item Preview */
.text-item-preview {
  background: var(--bg-tertiary);
  border-radius: var(--border-radius-sm);
  padding: 12px 16px;
  margin-top: 8px;
  font-size: 0.85rem;
  color: var(--text-secondary);
  max-height: 80px;
  overflow-y: auto;
  white-space: pre-wrap;
  word-break: break-word;
}

/* Share Text Section */
.share-text-section {
  background: var(--bg-secondary);
  border-radius: var(--border-radius);
  border: 1px solid var(--border-color);
  padding: 24px;
}

.share-text-section h3 {
  font-size: 1.1rem;
  margin-bottom: 8px;
}

.share-text-hint {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 20px;
}

.input-title {
  width: 100%;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-sm);
  color: var(--text-primary);
  font-family: inherit;
  font-size: 0.95rem;
  padding: 10px 16px;
  margin-bottom: 12px;
  transition: border-color var(--transition-fast);
}

.input-title:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

#shareTextInput {
  width: 100%;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-sm);
  color: var(--text-primary);
  font-family: inherit;
  font-size: 0.95rem;
  padding: 12px 16px;
  resize: vertical;
  margin-bottom: 16px;
  transition: border-color var(--transition-fast);
}

#shareTextInput:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

/* Buttons */
.btn {
  padding: 10px 20px;
  border: none;
  border-radius: var(--border-radius-sm);
  font-family: inherit;
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

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

.btn-primary:hover {
  background: var(--accent-secondary);
  box-shadow: 0 4px 12px var(--accent-glow);
}

.btn-secondary {
  background: var(--bg-tertiary);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

.btn-secondary:hover {
  background: var(--bg-hover);
  border-color: var(--accent-primary);
}

.btn-sm {
  padding: 6px 12px;
  font-size: 0.8rem;
}

.btn-icon {
  width: 36px;
  height: 36px;
  padding: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--border-radius-sm);
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.btn-icon:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
  border-color: var(--accent-primary);
}

.btn-icon.danger:hover {
  color: var(--error);
  border-color: var(--error);
}

/* Drag Overlay */
.drag-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(15, 17, 23, 0.9);
  z-index: 1000;
  display: none;
  align-items: center;
  justify-content: center;
  backdrop-filter: blur(4px);
}

.drag-overlay.visible {
  display: flex;
}

.drag-overlay-content {
  text-align: center;
  color: var(--accent-secondary);
}

.drag-overlay-icon {
  font-size: 5rem;
  margin-bottom: 16px;
  animation: pulse 1s ease infinite;
}

@keyframes pulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.1); }
}

.drag-overlay-content h2 {
  font-size: 2rem;
  font-weight: 700;
}

/* Toast Notifications */
.toast-container {
  position: fixed;
  bottom: 24px;
  right: 24px;
  z-index: 1000;
  display: flex;
  flex-direction: column-reverse;
  gap: 8px;
}

.toast {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-sm);
  padding: 12px 20px;
  box-shadow: var(--shadow-lg);
  animation: slideInRight 0.3s ease, fadeOut 0.3s ease 2.7s forwards;
  max-width: 350px;
  font-size: 0.9rem;
}

.toast.success {
  border-left: 4px solid var(--success);
}

.toast.error {
  border-left: 4px solid var(--error);
}

.toast.info {
  border-left: 4px solid var(--accent-primary);
}

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

@keyframes fadeOut {
  from { opacity: 1; }
  to { opacity: 0; }
}

/* Scrollbar */
::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: var(--bg-primary);
}

::-webkit-scrollbar-thumb {
  background: var(--bg-tertiary);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--bg-hover);
}

/* Responsive */
@media (max-width: 640px) {
  .app-header {
    flex-direction: column;
    gap: 12px;
    padding: 12px 16px;
  }
  
  .header-right {
    width: 100%;
    justify-content: space-between;
  }
  
  .app-main {
    padding: 16px 12px;
  }
  
  .drop-zone {
    padding: 32px 16px;
  }
  
  .tabs-container {
    flex-direction: column;
  }
  
  .tab {
    text-align: center;
  }
  
  .toast-container {
    left: 12px;
    right: 12px;
    bottom: 12px;
  }
  
  .toast {
    max-width: none;
  }
}

/* Upload progress bar */
.upload-progress {
  width: 100%;
  height: 4px;
  background: var(--bg-tertiary);
  border-radius: 2px;
  overflow: hidden;
  margin-top: 8px;
}

.upload-progress-bar {
  height: 100%;
  background: linear-gradient(90deg, var(--accent-primary), var(--accent-secondary));
  border-radius: 2px;
  transition: width 0.3s ease;
}

/* Login Overlay */
.login-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--bg-primary);
  z-index: 9999;
  display: none;
  align-items: center;
  justify-content: center;
  backdrop-filter: blur(8px);
}

.login-box {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  padding: 40px 36px;
  width: 100%;
  max-width: 400px;
  box-shadow: var(--shadow-lg);
  text-align: center;
}

.login-logo {
  margin-bottom: 32px;
}

.login-logo .logo-icon {
  font-size: 3rem;
  display: block;
  margin-bottom: 8px;
}

.login-logo h1 {
  font-size: 2rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 4px;
}

.login-subtitle {
  font-size: 0.8rem;
  color: var(--text-muted);
  letter-spacing: 1px;
  text-transform: uppercase;
}

.login-form {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.login-form input[type="text"],
.login-form input[type="password"] {
  width: 100%;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-sm);
  color: var(--text-primary);
  font-family: inherit;
  font-size: 1rem;
  padding: 12px 16px;
  transition: border-color var(--transition-fast);
}

.login-form input[type="text"]:focus,
.login-form input[type="password"]:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

.btn-login {
  width: 100%;
  padding: 12px 20px;
  font-size: 1rem;
  margin-top: 8px;
}

.login-error {
  display: none;
  background: rgba(255, 107, 107, 0.1);
  border: 1px solid var(--error);
  border-radius: var(--border-radius-sm);
  padding: 10px 16px;
  color: var(--error);
  font-size: 0.85rem;
  margin-bottom: 4px;
}

@media (max-width: 480px) {
  .login-box {
    margin: 16px;
    padding: 28px 24px;
  }
}