:root {
  --font-scale: 1;
  --bg-color: #0b0f19;
  --surface-color: #131b2e;
  --surface-color-subtle: #19233c;
  --border-color: #23304d;
  --border-color-focus: #4f46e5;
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent-primary: #6366f1;
  --accent-primary-hover: #4f46e5;
  --accent-success: #10b981;
  --accent-warning: #f59e0b;
  --accent-danger: #f43f5e;
  --font-main: 'Outfit', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'Fira Code', monospace;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.25);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.35), 0 2px 4px -1px rgba(0, 0, 0, 0.25);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -2px rgba(0, 0, 0, 0.3);
}

html[data-font-size="sm"] {
  --font-scale: 0.88;
}

html[data-font-size="md"] {
  --font-scale: 1;
}

html[data-font-size="lg"] {
  --font-scale: 1.15;
}

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

body {
  font-family: var(--font-main);
  background-color: var(--bg-color);
  color: var(--text-primary);
  line-height: 1.5;
  min-height: 100vh;
  padding: 10px 14px;
  font-size: calc(14px * var(--font-scale));
}

.app-container {
  max-width: 1320px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

/* Header */
.app-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 8px 16px;
  background-color: var(--surface-color);
  border: 1px solid var(--border-color);
  border-radius: 10px;
  box-shadow: var(--shadow-sm);
}

.logo-group {
  display: flex;
  align-items: center;
  gap: 12px;
}

.logo-icon {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, #4f46e5 0%, #7c3aed 100%);
  color: #ffffff;
  font-family: var(--font-mono);
  font-size: 22px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 8px;
  box-shadow: 0 0 12px rgba(99, 102, 241, 0.35);
}

.logo-text h1 {
  font-size: calc(18px * var(--font-scale));
  font-weight: 700;
  letter-spacing: -0.4px;
  color: #ffffff;
  line-height: 1.1;
}

.tagline {
  font-size: calc(11.5px * var(--font-scale));
  color: var(--text-secondary);
}

.header-controls {
  display: flex;
  align-items: center;
  gap: 12px;
}

/* Text Size Control */
.text-size-widget {
  display: flex;
  align-items: center;
  gap: 3px;
  background-color: var(--bg-color);
  padding: 2px 6px;
  border-radius: 6px;
  border: 1px solid var(--border-color);
}

.widget-label {
  font-size: 11px;
  color: var(--text-muted);
  font-weight: 600;
  margin-right: 2px;
  letter-spacing: 0.4px;
}

.size-btn {
  background: transparent;
  border: 1px solid transparent;
  color: var(--text-secondary);
  font-family: var(--font-mono);
  font-size: 11.5px;
  font-weight: 600;
  padding: 2px 7px;
  border-radius: 5px;
  cursor: pointer;
  transition: all 0.15s ease;
}

.size-btn:hover {
  color: #ffffff;
  background-color: var(--surface-color);
}

.size-btn.active {
  background-color: var(--accent-primary);
  color: #ffffff;
  border-color: var(--accent-primary);
}

.header-badges {
  display: flex;
  gap: 8px;
  align-items: center;
}

.badge {
  font-size: calc(10.5px * var(--font-scale));
  font-weight: 600;
  padding: 3px 8px;
  border-radius: 9999px;
  letter-spacing: 0.4px;
}

.badge-lisp {
  background-color: #1e1b4b;
  color: #a5b4fc;
  border: 1px solid #3730a3;
}

.badge-status {
  background-color: #064e3b;
  color: #6ee7b7;
  border: 1px solid #047857;
}

/* Main Layout */
.main-layout {
  display: grid;
  grid-template-columns: 1fr 1.05fr;
  gap: 14px;
  align-items: start;
}

@media (max-width: 1024px) {
  .main-layout {
    grid-template-columns: 1fr;
  }
}

/* Cards */
.card {
  background-color: var(--surface-color);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 14px 18px;
  box-shadow: var(--shadow-md);
  display: flex;
  flex-direction: column;
  gap: 11px;
}

.card-header {
  display: flex;
  align-items: center;
  gap: 10px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border-color);
}

.step-indicator {
  width: 22px;
  height: 22px;
  background-color: var(--accent-primary);
  color: #ffffff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 11.5px;
}

.card-header h2 {
  font-size: calc(15px * var(--font-scale));
  font-weight: 600;
  color: #ffffff;
}

/* Mode Tabs */
.mode-tabs {
  display: flex;
  gap: 4px;
  background-color: var(--bg-color);
  padding: 3px;
  border-radius: 8px;
  overflow-x: auto;
}

.tab-btn {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 4px;
  padding: 5px 8px;
  background: transparent;
  color: var(--text-secondary);
  border: none;
  border-radius: 6px;
  font-family: var(--font-main);
  font-size: calc(12px * var(--font-scale));
  font-weight: 500;
  cursor: pointer;
  white-space: nowrap;
  transition: all 0.15s ease;
}

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

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

.tab-icon {
  font-family: var(--font-mono);
  font-size: 12px;
}

/* Template Forms */
.template-panel {
  background-color: var(--surface-color-subtle);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 10px 12px;
}

.template-view {
  display: none;
}

.template-view.active {
  display: block;
}

.template-grid {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.template-row {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.field-group {
  display: flex;
  flex-direction: column;
  gap: 4px;
  flex: 1;
  min-width: 120px;
}

.field-group label {
  font-size: calc(11px * var(--font-scale));
  font-weight: 500;
  color: var(--text-secondary);
}

.math-input, .math-select {
  background-color: var(--bg-color);
  border: 1px solid var(--border-color);
  color: #ffffff;
  padding: 6px 10px;
  border-radius: 6px;
  font-family: var(--font-mono);
  font-size: calc(13px * var(--font-scale));
  outline: none;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.math-input:focus, .math-select:focus {
  border-color: var(--border-color-focus);
  box-shadow: 0 0 0 2px rgba(99, 102, 241, 0.25);
}

.fraction-divider {
  text-align: center;
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 11px;
  user-select: none;
}

/* Live Preview */
.preview-box {
  display: flex;
  flex-direction: column;
  gap: 3px;
  background-color: #0d1424;
  border: 1px solid #1e293b;
  border-left: 3px solid var(--accent-primary);
  padding: 8px 12px;
  border-radius: 6px;
}

.preview-label {
  font-size: 10px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-muted);
}

.math-preview {
  font-family: var(--font-mono);
  font-size: calc(13.5px * var(--font-scale));
  color: #a5b4fc;
  word-break: break-all;
}

/* Preset Chips */
.presets-section {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.presets-label {
  font-size: calc(11.5px * var(--font-scale));
  font-weight: 600;
  color: var(--text-secondary);
}

.preset-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.chip {
  background-color: var(--surface-color-subtle);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-family: var(--font-main);
  font-size: calc(11px * var(--font-scale));
  padding: 4px 9px;
  border-radius: 5px;
  cursor: pointer;
  transition: all 0.15s ease;
}

.chip:hover {
  background-color: #243254;
  color: #ffffff;
  border-color: #3b82f6;
}

.chip.active {
  background: linear-gradient(135deg, #4f46e5 0%, #6366f1 100%);
  color: #ffffff;
  border-color: #818cf8;
  box-shadow: 0 0 10px rgba(99, 102, 241, 0.4);
  font-weight: 600;
}

/* Action Bar (Hidden in Static Showcase Mode) */
.action-bar {
  display: flex;
}

body.static-mode .action-bar {
  display: none !important;
}

.btn-primary {
  width: 100%;
  padding: 9px 16px;
  background: linear-gradient(135deg, #4f46e5 0%, #6366f1 100%);
  color: #ffffff;
  border: none;
  border-radius: 8px;
  font-family: var(--font-main);
  font-size: calc(13.5px * var(--font-scale));
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  box-shadow: 0 2px 8px rgba(99, 102, 241, 0.3);
  transition: all 0.15s ease;
}

.btn-primary:hover {
  background: linear-gradient(135deg, #4338ca 0%, #4f46e5 100%);
  box-shadow: 0 4px 12px rgba(99, 102, 241, 0.45);
}

/* Output Card States */
.empty-state {
  text-align: center;
  padding: 36px 16px;
  color: var(--text-muted);
}

.empty-icon {
  font-size: 28px;
  margin-bottom: 8px;
}

.loading-state {
  text-align: center;
  padding: 36px 16px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  color: var(--text-secondary);
}

.spinner {
  width: 28px;
  height: 28px;
  border: 2.5px solid rgba(99, 102, 241, 0.2);
  border-top-color: var(--accent-primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

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

.hidden {
  display: none !important;
}

/* Result Hero */
.result-hero {
  background: linear-gradient(135deg, #111827 0%, #172554 100%);
  border: 1.5px solid #2563eb;
  border-radius: 10px;
  padding: 12px 14px;
  box-shadow: 0 4px 12px rgba(37, 99, 235, 0.15);
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.result-meta {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: calc(12.5px * var(--font-scale));
  color: #93c5fd;
}

.equals-sign {
  font-size: 16px;
  font-weight: bold;
}

.result-formula {
  font-family: var(--font-mono);
  font-size: calc(17px * var(--font-scale));
  font-weight: 600;
  color: #ffffff;
  padding: 6px 10px;
  background: rgba(0, 0, 0, 0.3);
  border-radius: 6px;
  word-break: break-all;
}

.result-actions {
  display: flex;
  justify-content: flex-end;
}

.copy-btn {
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.2);
  color: #ffffff;
  padding: 4px 9px;
  border-radius: 5px;
  font-size: 11px;
  font-family: var(--font-main);
  cursor: pointer;
}

.copy-btn:hover {
  background: rgba(255, 255, 255, 0.2);
}

/* Transparency Drawer */
.trace-drawer {
  background-color: var(--surface-color-subtle);
  border: 1px solid var(--border-color);
  border-radius: 10px;
  padding: 12px 14px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.drawer-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.algorithm-badge-group {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.aic-badge {
  font-family: var(--font-mono);
  font-size: calc(11px * var(--font-scale));
  font-weight: 600;
  padding: 3px 8px;
  background-color: #064e3b;
  color: #6ee7b7;
  border: 1px solid #059669;
  border-radius: 5px;
}

.algorithm-title {
  font-size: calc(15px * var(--font-scale));
  font-weight: 600;
  color: #ffffff;
}

.algorithm-desc {
  font-size: calc(12.5px * var(--font-scale));
  color: var(--text-secondary);
}

/* Cascade Section */
.cascade-section h4, .call-tree-section h4 {
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-muted);
  margin-bottom: 6px;
}

.cascade-timeline {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.timeline-step {
  display: flex;
  align-items: center;
  gap: 10px;
  background-color: var(--bg-color);
  padding: 6px 10px;
  border-radius: 6px;
  font-size: calc(12px * var(--font-scale));
  border-left: 3px solid var(--text-muted);
}

.timeline-step.success {
  border-left-color: var(--accent-success);
}

.timeline-step.failed {
  border-left-color: var(--accent-danger);
}

.step-badge {
  font-family: var(--font-mono);
  font-size: 10px;
  padding: 1px 5px;
  border-radius: 3px;
  font-weight: 600;
}

.step-badge.fail {
  background-color: #450a0a;
  color: #fca5a5;
}

.step-badge.pass {
  background-color: #064e3b;
  color: #6ee7b7;
}

/* Call Tree Viewer */
.call-tree-viewer {
  background-color: #070b14;
  border: 1px solid #1e293b;
  border-radius: 6px;
  padding: 10px;
  font-family: var(--font-mono);
  font-size: calc(12px * var(--font-scale));
  color: #e2e8f0;
  max-height: 220px;
  overflow-y: auto;
}

.tree-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 6px;
}

.toggle-tree-btn {
  background: transparent;
  border: none;
  color: var(--accent-primary);
  font-size: 11.5px;
  cursor: pointer;
}

.tree-node-row {
  padding: 2px 0;
  display: flex;
  align-items: baseline;
  gap: 5px;
}

.node-fn {
  color: #38bdf8;
  font-weight: 600;
}

.node-args {
  color: #94a3b8;
}

.node-res {
  color: #34d399;
}

/* Raw Trace Accordion */
.raw-trace-details {
  border-top: 1px solid var(--border-color);
  padding-top: 8px;
}

.raw-trace-details summary {
  cursor: pointer;
  color: var(--text-muted);
  font-size: 11px;
  font-weight: 500;
}

.raw-trace-pre {
  margin-top: 6px;
  background-color: #050811;
  border: 1px solid #1e293b;
  border-radius: 5px;
  padding: 8px 10px;
  font-family: var(--font-mono);
  font-size: 10.5px;
  color: #94a3b8;
  max-height: 140px;
  overflow-y: auto;
  white-space: pre-wrap;
}

/* Footer */
.app-footer {
  text-align: center;
  color: var(--text-muted);
  font-size: 11px;
  padding: 4px 0;
}