:root {
  --neutral-50: #fafafa;
  --neutral-100: #f5f5f5;
  --neutral-200: #e5e5e5;
  --neutral-300: #d4d4d4;
  --neutral-400: #a3a3a3;
  --neutral-500: #737373;
  --neutral-600: #525252;
  --neutral-700: #404040;
  --neutral-800: #262626;
  --neutral-900: #171717;
  --blue-50: #eff6ff;
  --blue-100: #dbeafe;
  --blue-200: #bfdbfe;
  --blue-300: #93c5fd;
  --blue-500: #3b82f6;
  --blue-600: #2563eb;
  --blue-700: #1d4ed8;
  --purple-50: #faf5ff;
  --purple-100: #f3e8ff;
  --purple-200: #e9d5ff;
  --purple-300: #d8b4fe;
  --purple-500: #a855f7;
  --purple-600: #9333ea;
  --purple-700: #7e22ce;
  --amber-50: #fffbeb;
  --amber-200: #fde68a;
  --amber-700: #b45309;
  --emerald-50: #ecfdf5;
  --emerald-200: #a7f3d0;
  --emerald-700: #047857;
  --rose-50: #fff1f2;
  --rose-200: #fecdd3;
  --rose-700: #be123c;
  --radius-lg: 10px;
  --radius-xl: 12px;
  --radius-2xl: 16px;
  --shadow-md: 0 10px 25px -15px rgba(0, 0, 0, 0.25);
  --transition: 150ms ease;
}

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

body {
  font-family: ui-sans-serif, system-ui, -apple-system, "Segoe UI", sans-serif;
  background: var(--neutral-50);
  color: var(--neutral-900);
  min-height: 100vh;
}

a {
  color: inherit;
  text-decoration: none;
}

img, svg {
  display: block;
}

button {
  border: none;
  background: none;
  color: inherit;
  cursor: pointer;
  font: inherit;
}

input, textarea {
  font: inherit;
}

.container {
  max-width: 64rem;
  margin: 0 auto;
  padding: 0 24px;
}

.container-md {
  max-width: 48rem;
  margin: 0 auto;
  padding: 0 24px;
}

.container-sm {
  max-width: 42rem;
  margin: 0 auto;
  padding: 0 24px;
}

.nav {
  background: #fff;
  border-bottom: 1px solid var(--neutral-200);
  position: sticky;
  top: 0;
  z-index: 10;
}

.nav-inner {
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 20px;
}

.nav-link {
  font-size: 14px;
  color: var(--neutral-500);
  transition: color var(--transition);
}

.nav-link:hover {
  color: var(--neutral-900);
}

.nav-link.active {
  color: var(--neutral-900);
  font-weight: 600;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 16px;
  border-radius: var(--radius-lg);
  font-size: 14px;
  border: 1px solid transparent;
  transition: background var(--transition), color var(--transition), border-color var(--transition);
}

.btn-primary {
  background: var(--neutral-900);
  color: #fff;
}

.btn-primary:hover {
  background: var(--neutral-800);
}

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

.btn-secondary:hover {
  background: var(--neutral-200);
}

.btn-outline {
  border-color: var(--neutral-200);
  color: var(--neutral-600);
  background: #fff;
}

.btn-outline:hover {
  border-color: var(--neutral-300);
}

.btn-ghost {
  color: var(--neutral-500);
}

.btn-ghost:hover {
  color: var(--neutral-900);
}

.btn-xs {
  padding: 6px 10px;
  font-size: 12px;
  border-radius: 8px;
}

.btn-lg {
  padding: 12px 18px;
  font-size: 15px;
}

.btn-disabled,
.btn:disabled {
  background: var(--neutral-300);
  border-color: var(--neutral-300);
  color: #fff;
  cursor: not-allowed;
}

.page {
  padding: 48px 0;
}

.page-compact {
  padding: 32px 0;
}

.page-title {
  font-size: 24px;
  font-weight: 600;
  margin-bottom: 8px;
  letter-spacing: -0.01em;
}

.page-subtitle {
  font-size: 14px;
  color: var(--neutral-500);
}

.section-divider {
  border-bottom: 1px solid var(--neutral-200);
  padding-bottom: 24px;
  margin-bottom: 24px;
}

.filters {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.filters-between {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.pill {
  padding: 6px 14px;
  border-radius: 999px;
  border: 1px solid var(--neutral-200);
  background: #fff;
  font-size: 12px;
  color: var(--neutral-600);
  transition: border-color var(--transition), background var(--transition), color var(--transition);
}

.pill:hover {
  border-color: var(--neutral-300);
}

.pill.active {
  background: var(--neutral-900);
  color: #fff;
  border-color: var(--neutral-900);
}

.tag {
  padding: 4px 10px;
  border-radius: 8px;
  border: 1px solid;
  font-size: 12px;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.tag--learning { background: var(--blue-50); color: var(--blue-700); border-color: var(--blue-200); }
.tag--thinking { background: var(--purple-50); color: var(--purple-700); border-color: var(--purple-200); }
.tag--creation { background: var(--amber-50); color: var(--amber-700); border-color: var(--amber-200); }
.tag--product { background: var(--emerald-50); color: var(--emerald-700); border-color: var(--emerald-200); }
.tag--emotion { background: var(--rose-50); color: var(--rose-700); border-color: var(--rose-200); }

.card {
  background: #fff;
  border: 1px solid var(--neutral-200);
  border-radius: var(--radius-xl);
  padding: 24px;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.card:hover {
  border-color: var(--neutral-300);
  box-shadow: var(--shadow-md);
}

.card-sm {
  padding: 20px;
}

.card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 16px;
}

.card-title {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 8px;
}

.card-title:hover {
  color: var(--neutral-700);
}

.card-text {
  font-size: 14px;
  color: var(--neutral-600);
  line-height: 1.6;
}

.card-meta {
  font-size: 12px;
  color: var(--neutral-500);
  display: flex;
  align-items: center;
  gap: 16px;
}

.card-actions {
  display: flex;
  gap: 8px;
  opacity: 0;
  transition: opacity var(--transition);
}

.card:hover .card-actions {
  opacity: 1;
}

.list-stack {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.list-tight {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.inline-muted {
  color: var(--neutral-400);
  font-size: 12px;
}

.stat {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  color: var(--neutral-500);
  margin-bottom: 24px;
}

.back-link:hover {
  color: var(--neutral-900);
}

.thread {
  display: flex;
  flex-direction: column;
  gap: 28px;
}

.thread-item {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.thread-header {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 12px;
}

.avatar {
  width: 28px;
  height: 28px;
  border-radius: 999px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 11px;
  font-weight: 600;
}

.avatar.user { background: var(--neutral-900); color: #fff; }
.avatar.ai { background: var(--neutral-100); color: var(--neutral-700); }

.thread-body {
  margin-left: 38px;
  font-size: 14px;
  color: var(--neutral-700);
  line-height: 1.65;
  white-space: pre-wrap;
}

.thread-divider {
  height: 1px;
  background: var(--neutral-100);
  margin-left: 38px;
}

.mode-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.mode-card {
  border: 2px solid var(--neutral-200);
  border-radius: var(--radius-xl);
  padding: 16px;
  text-align: left;
  transition: border-color var(--transition), background var(--transition);
}

.mode-card:hover {
  border-color: var(--neutral-900);
}

.mode-card.purple:hover {
  border-color: var(--purple-300);
  background: var(--purple-50);
}

.mode-card.blue:hover {
  border-color: var(--blue-300);
  background: var(--blue-50);
}

.mode-icon {
  width: 32px;
  height: 32px;
  border-radius: 10px;
  background: var(--neutral-100);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 12px;
}

.mode-icon.purple { background: var(--purple-100); color: var(--purple-600); }
.mode-icon.blue { background: var(--blue-100); color: var(--blue-600); }
.mode-icon.neutral { background: var(--neutral-100); color: var(--neutral-600); }

.mode-title {
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 6px;
}

.mode-desc {
  font-size: 12px;
  color: var(--neutral-500);
  line-height: 1.5;
}

.card-section {
  padding: 24px 32px;
  border-bottom: 1px solid var(--neutral-200);
}

.card-section:last-child {
  border-bottom: none;
}

.centered {
  display: flex;
  align-items: center;
  justify-content: center;
}

.centered-column {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
}

.hero-icon {
  width: 56px;
  height: 56px;
  border-radius: 18px;
  background: var(--neutral-900);
  color: #fff;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.form-card {
  background: #fff;
  border: 1px solid var(--neutral-200);
  border-radius: var(--radius-xl);
  padding: 32px;
}

.label {
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 12px;
  display: block;
}

.textarea {
  width: 100%;
  min-height: 140px;
  padding: 12px 16px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--neutral-200);
  font-size: 14px;
  resize: none;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.textarea:focus {
  outline: none;
  border-color: var(--neutral-900);
  box-shadow: 0 0 0 2px rgba(23, 23, 23, 0.15);
}

.textarea::placeholder {
  color: var(--neutral-400);
}

.toggle-group {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.helper {
  font-size: 12px;
  color: var(--neutral-500);
  margin-top: 8px;
}

.workspace-card {
  display: flex;
  align-items: flex-start;
  gap: 16px;
}

.workspace-main {
  flex: 1;
}

.status-badge {
  padding: 2px 8px;
  border-radius: 999px;
  font-size: 11px;
}

.status-in-progress { background: var(--blue-50); color: var(--blue-700); }
.status-completed { background: var(--neutral-100); color: var(--neutral-600); }
.status-draft { background: var(--amber-50); color: var(--amber-700); }

.menu {
  position: relative;
}

.menu-btn {
  padding: 6px;
  border-radius: 8px;
  color: var(--neutral-400);
}

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

.menu-dropdown {
  position: absolute;
  right: 0;
  top: calc(100% + 6px);
  background: #fff;
  border: 1px solid var(--neutral-200);
  border-radius: 10px;
  box-shadow: 0 12px 25px -18px rgba(0, 0, 0, 0.4);
  min-width: 160px;
  opacity: 0;
  transform: translateY(-4px);
  pointer-events: none;
  transition: opacity var(--transition), transform var(--transition);
  z-index: 5;
}

.menu:hover .menu-dropdown,
.menu:focus-within .menu-dropdown {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}

.menu-item {
  display: block;
  width: 100%;
  text-align: left;
  padding: 10px 12px;
  font-size: 13px;
  color: var(--neutral-700);
  background: #fff;
}

.menu-item:hover {
  background: var(--neutral-100);
}

.menu-item.danger {
  color: var(--rose-700);
}

.builder {
  min-height: calc(100vh - 64px);
  display: flex;
  flex-direction: column;
}

.builder-header {
  background: #fff;
  border-bottom: 1px solid var(--neutral-200);
  position: sticky;
  top: 64px;
  z-index: 5;
}

.builder-header-inner {
  padding: 16px 0;
}

.builder-actions {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 12px;
}

.builder-mode {
  display: flex;
  align-items: center;
  gap: 10px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--neutral-100);
  margin-bottom: 12px;
}

.builder-title {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 16px;
  font-weight: 600;
}

.builder-body {
  flex: 1;
  overflow-y: auto;
  padding: 32px 0;
}

.builder-input {
  background: #fff;
  border-top: 1px solid var(--neutral-200);
  position: sticky;
  bottom: 0;
}

.input-shell {
  background: var(--neutral-50);
  border: 1px solid var(--neutral-200);
  border-radius: var(--radius-xl);
  transition: border-color var(--transition), background var(--transition);
}

.input-shell:focus-within {
  border-color: var(--neutral-300);
  background: #fff;
}

.input-textarea {
  width: 100%;
  min-height: 60px;
  max-height: 200px;
  padding: 12px 16px;
  border: none;
  background: transparent;
  resize: none;
  font-size: 14px;
}

.input-textarea:focus {
  outline: none;
}

.input-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 16px 12px;
  font-size: 12px;
  color: var(--neutral-400);
}

.empty-state {
  text-align: center;
  padding: 48px 0;
  color: var(--neutral-500);
}

.round-icon {
  width: 24px;
  height: 24px;
  border-radius: 999px;
  background: var(--neutral-100);
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.inline-icon {
  width: 16px;
  height: 16px;
}

.icon-sm {
  width: 14px;
  height: 14px;
}

.icon-xs {
  width: 12px;
  height: 12px;
}

.icon-lg {
  width: 20px;
  height: 20px;
}

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

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

@media (max-width: 900px) {
  .mode-grid {
    grid-template-columns: 1fr;
  }

  .nav-inner {
    flex-direction: column;
    gap: 8px;
    height: auto;
    padding: 12px 0;
  }

  .nav-links {
    flex-wrap: wrap;
    justify-content: center;
  }
}

@media (max-width: 700px) {
  .card-section {
    padding: 20px;
  }

  .filters-between {
    flex-direction: column;
    align-items: flex-start;
  }

  .builder-header {
    top: 0;
  }
}