/* ========================================
   XMind to Canvas - 思维导图转换器
   Modern, Dark Theme UI
   ======================================== */

:root {
  /* Colors - Deep Ocean Theme */
  --bg-primary: #0a0e17;
  --bg-secondary: #111827;
  --bg-tertiary: #1a2332;
  --bg-card: #151d2b;
  --bg-hover: #1e293b;
  
  --accent-primary: #3b82f6;
  --accent-secondary: #8b5cf6;
  --accent-gradient: linear-gradient(135deg, #3b82f6 0%, #8b5cf6 100%);
  --accent-glow: 0 0 30px rgba(59, 130, 246, 0.3);
  
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  
  --border-color: #1e293b;
  --border-hover: #334155;
  
  --success: #10b981;
  --warning: #f59e0b;
  --error: #ef4444;
  
  /* Typography */
  --font-sans: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  
  /* Spacing */
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;
  --spacing-2xl: 48px;
  
  /* Border Radius */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
  --transition-slow: 400ms 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: var(--font-sans);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
}

/* ========================================
   App Layout
   ======================================== */

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

/* ========================================
   Header
   ======================================== */

.header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-md) var(--spacing-xl);
  background: rgba(10, 14, 23, 0.8);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 100;
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-primary);
}

.logo-icon {
  width: 28px;
  height: 28px;
  color: var(--accent-primary);
}

.nav {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

.nav-link {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  color: var(--text-secondary);
  background: var(--bg-tertiary);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.nav-link:hover {
  color: var(--text-primary);
  background: var(--bg-hover);
  transform: translateY(-2px);
}

/* ========================================
   Main Content
   ======================================== */

.main {
  flex: 1;
  display: flex;
  flex-direction: column;
  padding: var(--spacing-xl);
  max-width: 1400px;
  margin: 0 auto;
  width: 100%;
}

/* ========================================
   Upload Section
   ======================================== */

.upload-section {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-2xl);
}

.upload-container {
  width: 100%;
  max-width: 600px;
}

.upload-zone {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-2xl) var(--spacing-xl);
  background: var(--bg-card);
  border: 2px dashed var(--border-color);
  border-radius: var(--radius-xl);
  cursor: pointer;
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
}

.upload-zone::before {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--accent-gradient);
  opacity: 0;
  transition: opacity var(--transition-normal);
}

.upload-zone:hover {
  border-color: var(--accent-primary);
  box-shadow: var(--accent-glow);
}

.upload-zone:hover::before {
  opacity: 0.05;
}

.upload-zone.dragover {
  border-color: var(--accent-primary);
  background: var(--bg-hover);
  box-shadow: var(--accent-glow);
}

.upload-zone.dragover::before {
  opacity: 0.1;
}

.upload-icon {
  width: 80px;
  height: 80px;
  margin-bottom: var(--spacing-lg);
  color: var(--accent-primary);
  position: relative;
  z-index: 1;
}

.upload-icon svg {
  width: 100%;
  height: 100%;
}

.upload-title {
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
  position: relative;
  z-index: 1;
}

.upload-desc {
  color: var(--text-secondary);
  margin-bottom: var(--spacing-xs);
  position: relative;
  z-index: 1;
}

.upload-hint {
  font-size: 0.875rem;
  color: var(--text-muted);
  position: relative;
  z-index: 1;
}

/* ========================================
   Preview Section
   ======================================== */

.preview-section {
  display: flex;
  flex-direction: column;
  flex: 1;
  gap: var(--spacing-md);
  animation: fadeIn 0.4s ease;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.preview-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--spacing-md);
}

.file-info {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.file-icon {
  width: 24px;
  height: 24px;
  color: var(--accent-primary);
}

.file-name {
  font-size: 1.125rem;
  font-weight: 500;
  color: var(--text-primary);
}

.preview-actions {
  display: flex;
  gap: var(--spacing-sm);
}

/* ========================================
   Buttons
   ======================================== */

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-md);
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  font-weight: 500;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.btn-primary {
  background: var(--accent-gradient);
  color: white;
  box-shadow: 0 4px 12px rgba(59, 130, 246, 0.25);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(59, 130, 246, 0.35);
}

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

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

/* ========================================
   Stats Bar
   ======================================== */

.stats-bar {
  display: flex;
  gap: var(--spacing-xl);
  padding: var(--spacing-md) var(--spacing-lg);
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
}

.stat {
  display: flex;
  align-items: baseline;
  gap: var(--spacing-xs);
}

.stat-value {
  font-size: 1.5rem;
  font-weight: 700;
  font-family: var(--font-mono);
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

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

/* ========================================
   Canvas Wrapper
   ======================================== */

.canvas-wrapper {
  flex: 1;
  display: flex;
  flex-direction: column;
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  overflow: hidden;
  min-height: 500px;
}

.canvas-toolbar {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--bg-tertiary);
  border-bottom: 1px solid var(--border-color);
}

.toolbar-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  background: transparent;
  border: none;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
}

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

.toolbar-btn svg {
  width: 18px;
  height: 18px;
}

.zoom-level {
  font-size: 0.8125rem;
  font-family: var(--font-mono);
  color: var(--text-muted);
  min-width: 48px;
  text-align: center;
}

.toolbar-divider {
  width: 1px;
  height: 20px;
  background: var(--border-color);
  margin: 0 var(--spacing-xs);
}

.canvas-container {
  flex: 1;
  overflow: auto;
  position: relative;
  background: 
    radial-gradient(circle at center, var(--bg-secondary) 0%, var(--bg-primary) 100%),
    repeating-linear-gradient(0deg, transparent, transparent 20px, var(--border-color) 20px, var(--border-color) 21px),
    repeating-linear-gradient(90deg, transparent, transparent 20px, var(--border-color) 20px, var(--border-color) 21px);
  background-size: 100% 100%, 21px 21px, 21px 21px;
  background-blend-mode: normal;
}

.canvas-svg {
  display: block;
  transform-origin: 0 0;
}

/* Canvas Node Styles */
.canvas-node {
  cursor: pointer;
  transition: filter var(--transition-fast);
}

.canvas-node:hover {
  filter: brightness(1.1);
}

.canvas-node rect {
  fill: var(--bg-tertiary);
  stroke: var(--border-hover);
  stroke-width: 1.5;
  rx: 8;
}

.canvas-node.root rect {
  fill: var(--accent-primary);
  stroke: var(--accent-primary);
}

.canvas-node.root text {
  fill: white;
}

.canvas-node text {
  fill: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 13px;
  dominant-baseline: middle;
  text-anchor: middle;
}

.canvas-edge {
  stroke: var(--border-hover);
  stroke-width: 1.5;
  fill: none;
}

/* ========================================
   Loading Overlay
   ======================================== */

.loading-overlay {
  position: fixed;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: rgba(10, 14, 23, 0.9);
  backdrop-filter: blur(8px);
  z-index: 1000;
}

.loading-spinner {
  width: 48px;
  height: 48px;
  border: 3px solid var(--border-color);
  border-top-color: var(--accent-primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

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

.loading-text {
  margin-top: var(--spacing-md);
  color: var(--text-secondary);
  font-size: 0.9375rem;
}

/* ========================================
   Footer
   ======================================== */

.footer {
  padding: var(--spacing-md) var(--spacing-xl);
  text-align: center;
  color: var(--text-muted);
  font-size: 0.875rem;
  border-top: 1px solid var(--border-color);
}

/* ========================================
   Utilities
   ======================================== */

.hidden {
  display: none !important;
}

/* ========================================
   Responsive
   ======================================== */

@media (max-width: 768px) {
  .header {
    padding: var(--spacing-sm) var(--spacing-md);
  }
  
  .main {
    padding: var(--spacing-md);
  }
  
  .upload-zone {
    padding: var(--spacing-xl) var(--spacing-md);
  }
  
  .upload-icon {
    width: 60px;
    height: 60px;
  }
  
  .upload-title {
    font-size: 1.25rem;
  }
  
  .preview-header {
    flex-direction: column;
    align-items: flex-start;
  }
  
  .preview-actions {
    width: 100%;
  }
  
  .preview-actions .btn {
    flex: 1;
    justify-content: center;
  }
  
  .stats-bar {
    justify-content: space-around;
  }
}