:root {
  --gray-50: #f9fafb;
  --gray-100: #f3f4f6;
  --gray-200: #e5e7eb;
  --gray-300: #d1d5db;
  --gray-400: #9ca3af;
  --gray-500: #6b7280;
  --gray-600: #4b5563;
  --gray-700: #374151;
  --gray-800: #1f2937;
  --gray-900: #111827;
  --gray-950: #030712;

  --emerald-50: #ecfdf5;
  --emerald-100: #d1fae5;
  --emerald-200: #a7f3d0;
  --emerald-300: #6ee7b7;
  --emerald-400: #34d399;
  --emerald-500: #10b981;
  --emerald-600: #059669;
  --emerald-700: #047857;
  --emerald-800: #065f46;
  --emerald-900: #064e3b;
  --emerald-950: #022c22;

  --accent-primary: var(--emerald-500);
  --accent-bright: var(--emerald-400);
  --accent-soft: rgba(16, 185, 129, 0.1);
  
  --sidebar-w: 420px;
  --header-h: 48px;
  --footer-h: 30px;
  
  --font-ui: 'Inter', -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
  --font-brand: 'Outfit', sans-serif;

  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --shadow-inner: inset 0 2px 4px 0 rgb(0 0 0 / 0.05);

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 24px;
}

.theme-dark {
  --bg-app: var(--gray-950);
  --bg-pane: var(--gray-900);
  --bg-sidebar: var(--gray-950);
  --bg-input: var(--gray-900);
  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-dim: rgba(255, 255, 255, 0.04);
  --text-main: var(--gray-200);
  --text-dim: var(--gray-400);
  --text-muted: var(--gray-500);
  --bg-viewport: #111;
  --bg-glass: rgba(17, 24, 39, 0.6);
  --blur: 12px;
}

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

body {
  font-family: var(--font-ui);
  background-color: var(--bg-app);
  color: var(--text-main);
  height: 100vh;
  overflow: hidden;
  -webkit-font-smoothing: antialiased;
}

#app-shell {
  height: 100vh;
  width: 100vw;
  overflow: hidden;
}

#main-workspace {
  height: 100%;
  display: grid;
  grid-template-columns: var(--sidebar-w) 1fr;
  overflow: hidden;
}

/* Sidebar Wrapper */
#sidebar {
  background-color: var(--bg-sidebar);
  border-right: 1px solid var(--border-subtle);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  z-index: 100;
}

.samples-link {
  display: block;
  padding: 0.95rem 1.5rem 0.9rem;
  border-bottom: 1px solid var(--border-subtle);
  color: var(--gray-100);
  text-decoration: none;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.035), rgba(255, 255, 255, 0.015));
  transition: background-color 0.2s, color 0.2s, border-color 0.2s;
  cursor: pointer;
}

.samples-link::before {
  content: "\2197";
  display: inline-block;
  margin-right: 0.55rem;
  color: var(--accent-bright);
  font-size: 0.82rem;
  transform: translateY(-0.02rem);
}

.samples-link-label {
  display: inline-block;
  font-size: 0.83rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.samples-link-meta {
  display: block;
  margin-top: 0.22rem;
  margin-left: 1.35rem;
  color: var(--text-dim);
  font-size: 0.7rem;
  font-weight: 500;
}

.samples-link:hover {
  color: #ffffff;
  border-bottom-color: rgba(255, 255, 255, 0.14);
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.07), rgba(16, 185, 129, 0.05));
}

.samples-link:hover .samples-link-meta {
  color: var(--gray-300);
}

.sidebar-brand {
  padding: 1.5rem;
  border-bottom: 1px solid var(--border-subtle);
  background: var(--gray-900);
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  cursor: pointer;
}

.logo {
  background: linear-gradient(135deg, var(--emerald-400), var(--emerald-600));
  color: white;
  font-weight: 800;
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 8px;
  font-family: var(--font-brand);
  font-size: 1rem;
  box-shadow: 0 4px 12px rgba(16, 185, 129, 0.25);
}

.brand .product {
  font-family: var(--font-brand);
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--gray-100);
  letter-spacing: -0.02em;
}

.brand .component {
  font-weight: 400;
  color: var(--gray-500);
}

/* Sidebar Controls */
.controls-section {
  padding: 1.25rem 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  border-bottom: 1px solid var(--border-subtle);
  background: rgba(0,0,0,0.1);
}

.section-label {
  display: block;
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
}

.control-group {
  width: 100%;
}

select {
  width: 100%;
  appearance: none;
  background-color: var(--gray-800);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  color: var(--gray-200);
  padding: 0.6rem 2rem 0.6rem 1rem;
  font-family: var(--font-ui);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  transition: border-color 0.2s;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%236b7280' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 0.75rem center;
}

select:hover { border-color: var(--gray-600); }
select:focus { outline: none; border-color: var(--accent-primary); }

.button-row {
  display: flex;
  gap: 0.5rem;
  width: 100%;
}

.button-row .btn-primary, .button-row .btn-secondary {
  flex: 1;
  padding: 0.6rem 0.5rem;
  justify-content: center;
}

/* Editor in Sidebar */
#editor-section {
  flex: 1;
  display: flex;
  flex-direction: column;
  background: var(--gray-950);
}

.pane-header {
  height: var(--header-h);
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1rem;
  background: rgba(255,255,255,0.02);
}

.pane-header .label {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
}

.editor-container {
  flex: 1;
  position: relative;
}

#markdown-input {
  width: 100%;
  height: 100%;
  background: transparent;
  border: none;
  resize: none;
  padding: 1.5rem;
  color: var(--gray-300);
  font-family: var(--font-mono);
  font-size: 0.9rem;
  line-height: 1.6;
  outline: none;
}

.status-indicator {
  font-size: 0.7rem;
  color: var(--emerald-500);
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.status-indicator::before {
  content: ''; width: 6px; height: 6px; background: currentColor; border-radius: 50%;
}

/* Preview Pane */
#preview-pane {
  display: flex;
  flex-direction: column;
  background-color: var(--bg-viewport);
  position: relative;
  height: 100vh;
}

#render-viewport {
  flex: 1;
  overflow: auto;
  padding: 1.25rem 2rem;
  display: grid;
  justify-items: center;
  align-items: start;
  position: relative;
  cursor: grab;
  user-select: none;
  scrollbar-gutter: stable; /* Prevent horizontal shifts when vertical scrollbar appears */
}

#render-viewport:active { cursor: grabbing; }

.canvas-center {
  display: block;
}

canvas {
  display: block;
  background-color: white;
  box-shadow: 0 30px 60px rgba(0,0,0,0.6), 0 0 0 1px rgba(255,255,255,0.06);
  opacity: 1;
  transition: opacity 0.18s ease;
}

canvas.canvas-pending {
  opacity: 0;
  box-shadow: none;
}

/* Toolbar & Pager */
.pager-controls, .zoom-controls {
  display: flex; align-items: center; gap: 0.75rem; 
  font-size: 0.875rem; color: var(--text-dim);
}

.icon-btn {
  background: transparent; border: 1px solid transparent; color: var(--gray-400);
  width: 28px; height: 28px; border-radius: 4px; display: flex; align-items: center; justify-content: center;
  cursor: pointer; transition: all 0.2s;
}

.icon-btn:hover:not(:disabled) { background: var(--gray-800); color: white; }
.icon-btn:disabled { opacity: 0.3; cursor: not-allowed; }

#pager-text {
  min-width: 80px; text-align: center; font-weight: 500;
}

/* Buttons */
.btn-primary, .btn-secondary {
  padding: 0.5rem 1rem; border-radius: var(--radius-sm); font-weight: 600; font-size: 0.875rem;
  cursor: pointer; transition: all 0.2s; display: flex; align-items: center; gap: 0.4rem; font-family: var(--font-ui);
}

.btn-primary { background-color: var(--accent-primary); color: white; border: 1px solid var(--accent-primary); }
.btn-primary:hover { background-color: var(--emerald-600); border-color: var(--emerald-600); box-shadow: 0 0 20px rgba(16, 185, 129, 0.3); }

.btn-secondary { background-color: var(--gray-800); color: var(--gray-200); border: 1px solid var(--border-subtle); }
.btn-secondary:hover { background-color: var(--gray-700); border-color: var(--gray-500); }

/* Footer / Status Bar */
#preview-footer {
  height: var(--footer-h); background: var(--gray-900); border-top: 1px solid var(--border-subtle);
  display: flex; align-items: center; padding: 0 1rem; font-size: 0.7rem; color: var(--text-muted);
  position: relative;
}

#font-progress-container {
  position: absolute; top: -2px; left: 0; right: 0; height: 2px; background: rgba(255,255,255,0.05);
}

#font-progress-bar { height: 100%; background: var(--accent-primary); width: 0%; transition: width 0.3s; }

/* AST Drawer */
#ast-drawer {
  position: absolute; right: 0; top: 0; bottom: 0; width: 450px;
  background: var(--bg-pane); border-left: 1px solid var(--border-subtle); backdrop-filter: blur(var(--blur));
  display: flex; flex-direction: column; transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  z-index: 200; box-shadow: -20px 0 50px rgba(0,0,0,0.4);
}

#ast-drawer.collapsed { transform: translateX(100%); }

.drawer-header {
  height: var(--header-h); padding: 0 1rem; display: flex; align-items: center; justify-content: space-between;
  border-bottom: 1px solid var(--border-subtle); font-weight: 600;
}

.ast-content { flex: 1; overflow: auto; padding: 1.5rem; }
pre { font-family: var(--font-mono); font-size: 0.8rem; color: var(--emerald-400); line-height: 1.5; }

/* Utilities */
.hidden { display: none !important; }

.loader {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  z-index: 150;
  width: 24px; height: 24px; border: 2px solid var(--accent-soft); border-radius: 50%;
  border-top-color: var(--accent-primary); animation: spin 0.8s linear infinite;
}

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

/* Scrollbars */
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--gray-700); border-radius: 10px; }
::-webkit-scrollbar-thumb:hover { background: var(--gray-600); }