:root {
  /* Premium Professional Light Theme Palette */
  --color-bg: #ffffff; /* Crisp white base */
  --color-bg-secondary: #f8fafc; /* Very light slate */
  --color-bg-tertiary: #f1f5f9;
  
  --color-text: #0f172a; /* Deep slate text for high contrast but softer than black */
  --color-text-secondary: #475569;
  --color-text-tertiary: #64748b;
  
  --color-border: #e2e8f0;
  --color-border-light: #f1f5f9;
  
  /* Accent Colors */
  --color-primary: #0ea5e9; /* Professional vibrant blue */
  --color-primary-hover: #0284c7;
  --color-primary-light: rgba(14, 165, 233, 0.1);
  
  --color-success: #10b981; 
  --color-success-light: rgba(16, 185, 129, 0.1);
  
  --color-warning: #f59e0b;
  --color-warning-light: rgba(245, 158, 11, 0.1);
  
  --color-error: #ef4444; 
  --color-error-light: rgba(239, 68, 68, 0.1);
  
  --color-code-bg: #f8fafc;
  --color-code-text: #334155;
  
  /* Numbering / Badges */
  --color-stage-number: #f1f5f9;
  --color-stage-number-text: #475569;
  --color-stage-active: #0ea5e9;

  /* Typography */
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif;
  --font-mono: "JetBrains Mono", "Courier New", Courier, monospace;

  /* Spacing */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;

  /* Shadows - Clean, crisp, elevating */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -1px rgba(0, 0, 0, 0.03);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.05), 0 4px 6px -2px rgba(0, 0, 0, 0.025);
  --shadow-glow: 0 0 0 3px rgba(14, 165, 233, 0.15);

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 400ms cubic-bezier(0.4, 0, 0.2, 1);

  /* Border radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  background-color: var(--color-bg-tertiary); /* Soft background to make white panels pop */
  color: var(--color-text);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Clean Panels */
.glass-panel {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-md);
  border-radius: var(--radius-lg);
}

h1,h2,h3,h4,h5,h6 {
  font-weight: 600;
  line-height: 1.3;
  color: var(--color-text);
  margin-bottom: var(--space-4);
  letter-spacing: -0.015em;
}

h1 {
  font-size: 2.25rem;
  font-weight: 800;
  color: #0f172a;
}
h2 { font-size: 1.5rem; color: #1e293b; }
h3 { font-size: 1.25rem; color: #334155; }
h4 { font-size: 1.125rem; color: #475569; }

p {
  margin-bottom: var(--space-4);
  color: var(--color-text-secondary);
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: all var(--transition-fast);
}

a:hover {
  color: var(--color-primary-hover);
  text-decoration: underline;
}

pre, code {
  font-family: var(--font-mono);
}

code {
  background-color: var(--color-bg-tertiary);
  padding: var(--space-1) var(--space-2);
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
  font-size: 0.9em;
  color: #0f172a;
}

button {
  cursor: pointer;
  font-family: var(--font-sans);
  outline: none;
}

/* Layout */
.app-container {
  max-width: 1400px; /* Tighter width for professional feel */
  margin: 0 auto;
  padding: var(--space-6);
  width: 100%;
  flex: 1;
  display: flex;
  flex-direction: column;
}

.app-header {
  padding: var(--space-5) 0;
  margin-bottom: var(--space-5);
}

.header-content {
  max-width: 900px;
  text-align: left;
}

.app-header h1 {
  margin-bottom: var(--space-2);
}

.app-header p {
  color: var(--color-text-secondary);
  font-size: 1.05rem;
  margin-bottom: 0;
  max-width: 800px;
}

.app-footer {
  text-align: center;
  padding: var(--space-6);
  margin-top: auto;
  color: var(--color-text-tertiary);
  font-size: 0.875rem;
  border-top: 1px solid var(--color-border);
}

/* Tabs */
.app-tabs {
  display: flex;
  margin-bottom: var(--space-6);
  border-bottom: 2px solid var(--color-border);
  gap: var(--space-4);
}

.tab-button {
  background: none;
  border: none;
  padding: var(--space-3) var(--space-2);
  margin-bottom: -2px; /* Pull down to overlap border */
  font-size: 1rem;
  font-weight: 500;
  color: var(--color-text-secondary);
  border-bottom: 2px solid transparent;
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.tab-button:hover {
  color: var(--color-text);
}

.tab-button.active {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}

.tab-button svg {
  opacity: 0.7;
  transition: opacity var(--transition-fast);
}

.tab-button.active svg {
  opacity: 1;
}

.tab-content { display: none; animation: fadeIn var(--transition-fast); }
.tab-content.active { display: block; }

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(5px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Workspace layout */
.workspace {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-6);
  height: calc(100vh - 280px);
  min-height: 700px;
}

.editor-panel,
.compilation-panel {
  display: flex;
  flex-direction: column;
  overflow: hidden;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
}

.panel-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--space-3) var(--space-5);
  background-color: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
}

.panel-header h2 {
  margin-bottom: 0;
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-secondary);
  font-weight: 600;
}

.panel-actions {
  display: flex;
  gap: var(--space-2);
}

/* Editor */
.editor-container {
  flex: 1;
  overflow: hidden;
  border-bottom: 1px solid var(--color-border);
  background: #ffffff;
}

/* CodeMirror Default Light Theme Tweaks */
.CodeMirror {
  height: 100% !important;
  font-family: var(--font-mono);
  font-size: 0.95rem;
  line-height: 1.6;
}
.CodeMirror-gutters {
  background: var(--color-bg-secondary) !important;
  border-right: 1px solid var(--color-border) !important;
}
.CodeMirror-linenumber { color: var(--color-text-tertiary) !important; }

.input-section {
  padding: var(--space-4) var(--space-5);
  background-color: var(--color-bg);
}

.input-section h3 {
  margin-bottom: var(--space-1);
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-secondary);
}

.input-hint {
  color: var(--color-text-tertiary);
  font-size: 0.85rem;
  margin-bottom: var(--space-2);
}

#inputData {
  width: 100%;
  height: 80px;
  padding: var(--space-3);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: 0.9rem;
  resize: vertical;
  background-color: var(--color-bg);
  color: var(--color-text);
  transition: all var(--transition-fast);
}

#inputData:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: var(--shadow-glow);
}

/* Pipeline Progress tracker */
.pipeline-progress {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-5) var(--space-6);
  background: var(--color-bg-secondary);
  border-bottom: 1px solid var(--color-border);
  position: relative;
}
.pipeline-progress::after {
  content: '';
  position: absolute;
  top: 50%;
  left: var(--space-6);
  right: var(--space-6);
  height: 2px;
  background: var(--color-border);
  z-index: 1;
}
.pipeline-progress-bar {
  position: absolute;
  top: 50%;
  left: var(--space-6);
  height: 2px;
  background: var(--color-primary);
  z-index: 2;
  transition: width 0.5s ease;
  width: 0%;
}
.pipeline-node {
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--color-border);
  border: 3px solid var(--color-bg);
  z-index: 3;
  transition: all var(--transition-normal);
  box-shadow: 0 0 0 1px var(--color-border);
}
.pipeline-node.active {
  background: var(--color-primary);
  box-shadow: 0 0 0 2px var(--color-primary-light);
  transform: scale(1.2);
}
.pipeline-node.success {
  background: var(--color-success);
  box-shadow: 0 0 0 1px var(--color-border);
}
.pipeline-node.error {
  background: var(--color-error);
  box-shadow: 0 0 0 1px var(--color-border);
}

/* Compilation stages */
.compilation-panel { overflow: hidden; }

.compilation-stages {
  flex: 1;
  overflow-y: auto;
  padding: var(--space-4);
  background: var(--color-bg-tertiary); /* Distinct staging area */
}

.stage {
  margin-bottom: var(--space-3);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  background: var(--color-bg);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-fast);
}

.stage:hover {
  border-color: #cbd5e1;
}

.stage-header {
  background-color: var(--color-bg);
  padding: var(--space-3) var(--space-4);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px solid transparent;
}

.stage:not(.collapsed) .stage-header {
  border-bottom-color: var(--color-border);
  background-color: var(--color-bg-secondary);
}

.stage-title {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.stage-number {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 24px;
  height: 24px;
  background-color: var(--color-stage-number);
  color: var(--color-stage-number-text);
  border-radius: var(--radius-sm);
  font-size: 0.8rem;
  font-weight: 600;
}

.stage-title h3 {
  margin-bottom: 0;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--color-text);
}

.stage-toggle .icon-chevron {
  transition: transform var(--transition-normal);
  color: var(--color-text-tertiary);
  width: 18px;
  height: 18px;
}

.stage.collapsed .stage-toggle .icon-chevron {
  transform: rotate(-90deg);
}

.stage-content {
  padding: var(--space-4);
  background-color: var(--color-bg);
  max-height: 500px;
  overflow-y: auto;
  transition: max-height var(--transition-normal), padding var(--transition-normal), opacity var(--transition-normal);
}

.stage.collapsed .stage-content {
  max-height: 0;
  padding-top: 0;
  padding-bottom: 0;
  overflow: hidden;
  opacity: 0;
}

.stage-description {
  margin-bottom: var(--space-3);
  font-size: 0.85rem;
  color: var(--color-text-secondary);
}

.code-output {
  background-color: var(--color-code-bg);
  padding: var(--space-3);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  line-height: 1.5;
  overflow-x: auto;
  white-space: pre-wrap;
  word-wrap: break-word;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  color: var(--color-code-text);
}

/* Syntax Highlighting for Light Mode */
.token-keyword { color: #0284c7; font-weight: 600; }
.token-identifier { color: #0f172a; }
.token-number { color: #059669; }
.token-operator { color: #d97706; }
.token-string { color: #16a34a; }

.ast-node { color: #0284c7; font-weight: 500; }
.ast-prop { color: #7c3aed; }

.error-output {
  background-color: var(--color-error-light);
  color: #b91c1c;
  border-color: #fca5a5;
}

.optimization-log {
  background-color: var(--color-success-light);
  border: 1px solid #a7f3d0;
  color: #047857;
  padding: var(--space-3);
  margin-bottom: var(--space-3);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  border-radius: var(--radius-sm);
  white-space: pre-wrap;
}

/* Execution Results */
.execution-info {
  display: flex;
  justify-content: space-between;
  margin-bottom: var(--space-3);
  padding: var(--space-2) var(--space-3);
  background-color: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
}

.execution-metric {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: 0.85rem;
  font-family: var(--font-mono);
  color: var(--color-text-secondary);
}

.execution-metric svg { color: var(--color-primary); width: 14px; height: 14px; }

.output-section h4, .error-section h4 {
  margin-bottom: var(--space-2);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-tertiary);
  font-weight: 600;
}

.error-section { display: none; }

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  font-weight: 500;
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.btn svg { width: 14px; height: 14px; }

.btn-primary {
  background-color: var(--color-primary);
  color: white;
  box-shadow: var(--shadow-sm);
}
.btn-primary:hover:not(:disabled) {
  background-color: var(--color-primary-hover);
}
.btn-primary:disabled {
  background-color: #cbd5e1;
  color: #f1f5f9;
  cursor: not-allowed;
  box-shadow: none;
}

.btn-secondary {
  background-color: var(--color-bg);
  color: var(--color-text);
  border-color: var(--color-border);
}
.btn-secondary:hover {
  background-color: #f8fafc;
  border-color: #cbd5e1;
}

.btn-text {
  background: none;
  color: var(--color-text-tertiary);
  padding: var(--space-1) var(--space-2);
}
.btn-text:hover { color: var(--color-text); background-color: var(--color-bg-tertiary); }

/* Status indicators */
.success { color: #10b981 !important; }
.error { color: #ef4444 !important; }
.info { color: #0ea5e9 !important; }
.warning { color: #f59e0b !important; }

/* Custom Scrollbars */
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: var(--color-bg-tertiary); }
::-webkit-scrollbar-thumb { background: #cbd5e1; border-radius: 4px; border: 2px solid var(--color-bg-tertiary); }
::-webkit-scrollbar-thumb:hover { background: #94a3b8; }

/* Loading animation pulse */
.loading {
  display: inline-block;
  width: 14px;
  height: 14px;
  border: 2px solid rgba(255,255,255,0.3);
  border-top: 2px solid #fff;
  border-radius: 50%;
  animation: spin 1s linear infinite;
}
@keyframes spin { 100% { transform: rotate(360deg); } }

/* Typing Text Animation Class (added via JS) */
.typewriter {
  overflow: hidden;
  border-right: 2px solid var(--color-primary);
  white-space: pre-wrap;
  animation: typing 3.5s steps(40, end), blink-caret .75s step-end infinite;
}
@keyframes blink-caret { from, to { border-color: transparent } 50% { border-color: var(--color-primary); } }

/* Documentation Page - Clean Styling */
.documentation-container { display: grid; grid-template-columns: 240px 1fr; gap: var(--space-8); max-width: 1200px; margin: 0 auto; }
.doc-sidebar { position: sticky; top: var(--space-6); height: fit-content; }
.doc-nav { background-color: var(--color-bg); border: 1px solid var(--color-border); border-radius: var(--radius-md); padding: var(--space-4); box-shadow: var(--shadow-sm); }
.doc-nav h3 { font-size: 0.95rem; margin-bottom: var(--space-4); padding-bottom: var(--space-2); border-bottom: 1px solid var(--color-border-light); color: var(--color-text); text-transform: uppercase; letter-spacing: 0.05em; }
.doc-nav ul { list-style: none; }
.doc-nav li { margin-bottom: var(--space-1); }
.doc-nav a { display: block; padding: var(--space-2) var(--space-3); border-radius: var(--radius-sm); color: var(--color-text-secondary); transition: all var(--transition-fast); text-decoration: none; font-size: 0.95rem; border-left: 2px solid transparent;}
.doc-nav a:hover { background-color: var(--color-bg-tertiary); color: var(--color-text); }
.doc-nav a.active { background-color: var(--color-primary-light); color: var(--color-primary); font-weight: 500; border-left-color: var(--color-primary); border-radius: 0 var(--radius-sm) var(--radius-sm) 0;}
.doc-content { background-color: var(--color-bg); border: 1px solid var(--color-border); border-radius: var(--radius-lg); padding: var(--space-8); box-shadow: var(--shadow-sm); }
.doc-section { margin-bottom: var(--space-8); padding-bottom: var(--space-6); border-bottom: 1px solid var(--color-border-light); }
.doc-section:last-child { margin-bottom: 0; padding-bottom: 0; border-bottom: none; }
.doc-section h2 { font-size: 1.75rem; color: var(--color-text); margin-bottom: var(--space-4); }
.doc-section p { color: var(--color-text-secondary); font-size: 1rem; line-height: 1.7; }
.code-example { margin-bottom: var(--space-6); border: 1px solid var(--color-border); border-radius: var(--radius-md); overflow: hidden; }
.code-block { background-color: var(--color-code-bg); padding: var(--space-4); font-family: var(--font-mono); font-size: 0.9rem; border-bottom: 1px solid var(--color-border); color: var(--color-code-text); border-radius: 0; margin: 0; }
.code-example .code-output { background-color: #ffffff; padding: var(--space-4); }
.feature-list li { margin-bottom: var(--space-3); line-height: 1.6; color: var(--color-text-secondary); }
.feature-list li strong { color: var(--color-text); }
.feature-list li::before { color: var(--color-primary); }

@media (max-width: 1200px) {
  .workspace { grid-template-columns: 1fr; height: auto; }
  .editor-panel, .compilation-panel { height: 600px; }
}
@media (max-width: 768px) {
  .documentation-container { grid-template-columns: 1fr; }
  .doc-sidebar { position: static; }
  .app-tabs { overflow-x: auto; padding-bottom: var(--space-2); }
}