:root {
  /* Brand - Indigo */
  --brand-50: #EEF0FB;
  --brand-100: #DDE0F7;
  --brand-600: #5E6AD2;
  --brand-700: #4A56C0;
  --brand-fg: var(--brand-600);

  /* Neutrals */
  --neutral-0: #FFFFFF;
  --neutral-50: #F8FAFC;
  --neutral-100: #F1F5F9;
  --neutral-200: #E2E8F0;
  --neutral-300: #CBD5E1;
  --neutral-400: #94A3B8;
  --neutral-500: #64748B;
  --neutral-600: #475569;
  --neutral-700: #334155;
  --neutral-800: #1E293B;
  --neutral-900: #0F172A;

  /* Semantic */
  --bg-canvas: var(--neutral-50);
  --bg-surface: var(--neutral-0);
  --text-primary: var(--neutral-900);
  --text-muted: var(--neutral-600);
  --border-default: var(--neutral-200);
  
  --success-fg: #15803D;
  --success-bg: #DCFCE7;
  --error-fg: #B91C1C;
  --error-bg: #FEE2E2;
  --info-fg: #1D4ED8;
  --info-bg: #DBEAFE;

  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --radius-md: 6px;
  --radius-lg: 8px;
  --shadow-sm: 0 1px 2px 0 rgba(15, 23, 42, 0.05), 0 1px 3px 0 rgba(15, 23, 42, 0.06);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);

  --duration-150: 150ms;
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  background: var(--bg-canvas);
  color: var(--text-primary);
  -webkit-font-smoothing: antialiased;
}

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

.topbar {
  height: 64px;
  background: var(--bg-surface);
  border-bottom: 1px solid var(--border-default);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 32px;
  position: sticky;
  top: 0;
  z-index: 10;
}

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

.logo-icon {
  color: var(--brand-600);
  width: 32px;
  height: 32px;
}

.logo-text {
  font-size: 20px;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.content {
  flex: 1;
  padding: 48px 24px;
}

.container {
  max-width: 1000px;
  margin: 0 auto;
}

.card {
  background: var(--bg-surface);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.card-header {
  padding: 24px 24px 16px;
}

.card-title {
  margin: 0;
  font-size: 18px;
  font-weight: 600;
}

.card-desc {
  margin: 4px 0 0;
  font-size: 14px;
  color: var(--text-muted);
}

.card-body {
  padding: 0 24px 24px;
}

.text-input {
  width: 100%;
  min-height: 200px;
  padding: 16px;
  border: 1px solid var(--border-default);
  border-radius: var(--radius-md);
  font-family: inherit;
  font-size: 15px;
  line-height: 1.5;
  resize: vertical;
  background: var(--bg-canvas);
  transition: border-color var(--duration-150) var(--ease-out);
}

.text-input:focus {
  outline: none;
  border-color: var(--brand-600);
  box-shadow: 0 0 0 3px var(--brand-50);
}

.input-actions {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 12px;
  margin-top: 16px;
  flex-wrap: wrap;
}

.spacer {
  flex: 1;
}

.sample-text-selector {
  display: flex;
  align-items: center;
  gap: 8px;
}

.sample-text-selector .label {
  font-size: 12px;
  font-weight: 600;
  color: var(--neutral-400);
  text-transform: uppercase;
}

.sample-btn {
  background: var(--neutral-100);
  border: 1px solid var(--neutral-200);
  padding: 4px 10px;
  border-radius: 4px;
  font-size: 12px;
  font-weight: 500;
  cursor: pointer;
  color: var(--neutral-600);
  transition: all var(--duration-150) var(--ease-out);
}

.sample-btn:hover {
  background: var(--neutral-200);
  color: var(--neutral-900);
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  height: 40px;
  padding: 0 20px;
  border-radius: var(--radius-md);
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--duration-150) var(--ease-out);
  border: 1px solid transparent;
}

.btn-primary {
  background: var(--brand-600);
  color: white;
}

.btn-primary:hover:not(:disabled) {
  background: var(--brand-700);
}

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

.btn-secondary:hover:not(:disabled) {
  background: var(--neutral-50);
  border-color: var(--neutral-300);
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.results-section {
  margin-top: 48px;
}

.results-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
}

.result-card {
  display: flex;
  flex-direction: column;
}

.result-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: 12px;
}

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

.result-icon {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.result-card--brand .result-icon {
  background: var(--brand-50);
  color: var(--brand-600);
}

.result-card--info .result-icon {
  background: var(--info-bg);
  color: var(--info-fg);
}

.result-card--success .result-icon {
  background: var(--success-bg);
  color: var(--success-fg);
}

.result-title {
  margin: 0;
  font-size: 16px;
  font-weight: 600;
}

.result-body {
  flex: 1;
}

.result-text {
  margin: 0;
  font-size: 14px;
  line-height: 1.6;
  white-space: pre-wrap;
  color: var(--neutral-700);
}

.icon-btn {
  background: none;
  border: none;
  color: var(--neutral-500);
  cursor: pointer;
  padding: 8px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--duration-150) var(--ease-out);
}

.icon-btn:hover {
  background: var(--neutral-100);
  color: var(--neutral-900);
}

.success-text {
  color: var(--success-fg);
}

.alert {
  margin-top: 24px;
  padding: 16px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 14px;
}

.alert-error {
  background: var(--error-bg);
  color: var(--error-fg);
  border: 1px solid #FCA5A5;
}

.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  padding: 80px 24px;
  color: var(--neutral-400);
}

.empty-icon {
  margin-bottom: 24px;
  color: var(--neutral-200);
}

.empty-state h3 {
  margin: 0;
  font-size: 18px;
  font-weight: 600;
  color: var(--neutral-700);
}

.empty-state p {
  margin: 8px 0 0;
  font-size: 14px;
  max-width: 400px;
  line-height: 1.5;
}

.footer {
  padding: 32px;
  text-align: center;
  font-size: 13px;
  color: var(--neutral-400);
  border-top: 1px solid var(--border-default);
  background: var(--bg-surface);
}

.spinner {
  animation: spin 1s linear infinite;
}

@keyframes spin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

@media (max-width: 768px) {
  .results-grid {
    grid-template-columns: 1fr;
  }
  
  .topbar {
    padding: 0 16px;
  }
  
  .content {
    padding: 24px 16px;
  }
}