:root {
  --font-main: 'Satoshi', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --bg-canvas: #ffffff;
  --bg-soft: #f4f4f5;
  --bg-subtle: #fafafa;
  --text-black: #0f172a;
  --text-muted: #52525b;
  --text-light: #a1a1aa;
  --border-hairline: rgba(0, 0, 0, 0.08);
  --border-strong: rgba(0, 0, 0, 0.14);

  /* Warm study highlight tones */
  --anchor-bg: rgba(245, 158, 11, 0.14);
  --anchor-bg-hover: rgba(245, 158, 11, 0.24);
  --anchor-border: rgba(217, 119, 6, 0.48);

  /* Purposeful semantic close/reset accent */
  --danger-bg: rgba(239, 68, 68, 0.1);
  --danger-bg-hover: rgba(239, 68, 68, 0.16);
  --danger-text: #dc2626;

  --ease-smooth: cubic-bezier(0.22, 1, 0.36, 1);
}

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

body {
  font-family: var(--font-main);
  background: var(--bg-canvas);
  color: var(--text-black);
  height: 100vh;
  height: 100dvh;
  width: 100vw;
  overflow: hidden;
  -webkit-font-smoothing: antialiased;
}

.hidden {
  display: none !important;
}

/* Unified Button Convention */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.35rem;
  font-family: inherit;
  font-weight: 600;
  border-radius: 999px;
  cursor: pointer;
  transition: background 0.16s ease, color 0.16s ease, border-color 0.16s ease, opacity 0.16s ease, transform 0.12s ease;
  border: 1px solid transparent;
  white-space: nowrap;
}

.btn:active {
  transform: scale(0.98);
}

.btn:disabled {
  opacity: 0.45;
  cursor: not-allowed;
  transform: none;
}

.btn-primary {
  background: var(--text-black);
  color: #ffffff;
  padding: 0.5rem 1.1rem;
  font-size: 0.84rem;
}

.btn-primary:hover {
  opacity: 0.88;
}

.btn-secondary {
  background: var(--bg-soft);
  color: var(--text-black);
  border-color: var(--border-hairline);
  padding: 0.32rem 0.72rem;
  font-size: 0.75rem;
}

.btn-secondary:hover {
  background: #e4e4e7;
}

/* Full-Viewport Split Shell (Claude-inspired spacious proportions) */
.workspace-shell {
  display: flex;
  width: 100vw;
  height: 100vh;
  height: 100dvh;
  overflow: hidden;
  background: var(--bg-canvas);
}

/* Left Column: Full-Bleed Main Pane */
.main-pane {
  flex: 1 1 100%;
  min-width: 0;
  height: 100vh;
  height: 100dvh;
  display: flex;
  flex-direction: column;
  background: var(--bg-canvas);
  transition: flex-basis 0.42s var(--ease-smooth);
}

.workspace-shell.has-open-bucket .main-pane {
  flex: 1 1 50%;
}

/* Lightweight Top Title Bar inside Left Pane */
.pane-topbar {
  height: 52px;
  padding: 0 2.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-shrink: 0;
}

.topbar-left {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  min-width: 0;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  flex-shrink: 0;
}

.brand-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--text-black);
  flex-shrink: 0;
}

.brand-name {
  font-weight: 700;
  font-size: 0.94rem;
  letter-spacing: -0.01em;
  color: var(--text-black);
  flex-shrink: 0;
}

/* Collapsible Left Navigation Sidebar (Crisp White & Lightweight) */
.nav-sidebar {
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  width: 260px;
  background: #ffffff;
  border-right: 1px solid var(--border-hairline);
  z-index: 80;
  transform: translateX(-100%);
  transition: transform 0.34s var(--ease-smooth);
}

.workspace-shell.is-sidebar-open .nav-sidebar {
  transform: translateX(0);
}

.sidebar-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.16);
  opacity: 0;
  pointer-events: none;
  z-index: 75;
  transition: opacity 0.28s ease;
}

.workspace-shell.is-sidebar-open .sidebar-backdrop {
  opacity: 1;
  pointer-events: auto;
}

.nav-sidebar-inner {
  height: 100%;
  display: flex;
  flex-direction: column;
  padding: 0.75rem 0.9rem 1rem;
  gap: 0.85rem;
}

.nav-sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 36px;
  padding: 0 0.35rem;
}

.nav-new-chat-btn {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--bg-subtle);
  color: var(--text-black);
  border: 1px solid var(--border-hairline);
  padding: 0.5rem 0.7rem;
  border-radius: 10px;
  font-family: inherit;
  font-size: 0.83rem;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.15s ease, border-color 0.15s ease;
}

.nav-new-chat-btn svg {
  width: 15px;
  height: 15px;
  stroke: currentColor;
  stroke-width: 1.9;
  fill: none;
  stroke-linecap: round;
}

.nav-new-chat-btn:hover {
  background: var(--bg-soft);
  border-color: var(--border-strong);
}

.nav-section {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  flex: 1;
  overflow-y: auto;
  margin-top: 0.25rem;
}

.nav-section-label {
  font-size: 0.68rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  color: var(--text-light);
  padding: 0 0.5rem 0.15rem;
}

.nav-thread-list {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
}

.nav-thread-row {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  border-radius: 8px;
  padding-right: 0.25rem;
  transition: background 0.15s ease;
}

.nav-thread-row.active,
.nav-thread-row:hover {
  background: var(--bg-soft);
}

.nav-thread-item {
  flex: 1;
  min-width: 0;
  text-align: left;
  background: transparent;
  border: none;
  border-radius: 8px;
  padding: 0.48rem 0.6rem;
  font-family: inherit;
  font-size: 0.83rem;
  font-weight: 500;
  color: var(--text-muted);
  cursor: pointer;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.nav-thread-row.active .nav-thread-item,
.nav-thread-row:hover .nav-thread-item {
  color: var(--text-black);
}

.nav-thread-delete {
  width: 28px;
  height: 28px;
  border: none;
  background: transparent;
  color: var(--text-muted);
  border-radius: 6px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  opacity: 0;
  flex-shrink: 0;
  transition: opacity 0.14s ease, color 0.14s ease, background 0.14s ease;
}

.nav-thread-row.active .nav-thread-delete,
.nav-thread-row:hover .nav-thread-delete {
  opacity: 1;
}

@media (hover: none), (max-width: 860px) {
  .nav-thread-delete {
    opacity: 1;
  }
}

.nav-thread-row.active .nav-thread-delete:hover,
.nav-thread-row:hover .nav-thread-delete:hover,
.nav-thread-delete:hover {
  opacity: 1;
  color: #ffffff;
  background: var(--text-black);
}

.nav-thread-delete svg {
  width: 14px;
  height: 14px;
  stroke: currentColor;
  stroke-width: 1.9;
  fill: none;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.nav-sidebar-footer {
  padding-top: 0.65rem;
  border-top: 1px solid var(--border-hairline);
}

.nav-mode-btn {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.48rem 0.6rem;
  border-radius: 8px;
  border: 1px solid transparent;
  background: transparent;
  font-family: inherit;
  font-size: 0.79rem;
  font-weight: 500;
  color: var(--text-muted);
  cursor: pointer;
  text-align: left;
  transition: background 0.15s ease, color 0.15s ease;
}

.nav-mode-btn:hover {
  background: var(--bg-soft);
  color: var(--text-black);
}

.mode-status-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--text-light);
  flex-shrink: 0;
}

.mode-status-dot.is-live {
  background: #16a34a;
}

.btn-sidebar-toggle {
  width: 28px;
  height: 28px;
  background: transparent;
  color: var(--text-muted);
  margin-left: -4px;
}

.btn-sidebar-toggle svg,
#btn-close-sidebar svg {
  width: 16px;
  height: 16px;
  stroke-width: 1.75;
}

.btn-sidebar-toggle:hover {
  background: rgba(0, 0, 0, 0.05);
  color: var(--text-black);
}

.topic-title {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--text-black);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* Floating Text-Selection "Clarify ↗" Pill */
.selection-clarify-btn {
  position: fixed;
  z-index: 60;
  background: var(--text-black);
  color: #ffffff;
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: 999px;
  padding: 0.34rem 0.78rem;
  font-family: inherit;
  font-size: 0.76rem;
  font-weight: 600;
  letter-spacing: 0.01em;
  cursor: pointer;
  box-shadow: 0 6px 18px rgba(0, 0, 0, 0.16);
  transform: translate(-50%, -100%);
  transition: opacity 0.14s ease, transform 0.14s ease;
  white-space: nowrap;
}

.selection-clarify-btn:hover {
  transform: translate(-50%, -100%) scale(1.03);
}

.selection-clarify-btn.is-below {
  transform: translate(-50%, 0);
}

.selection-clarify-btn.is-below:hover {
  transform: translate(-50%, 0) scale(1.03);
}

/* Blank Empty State (Claude / ChatGPT Centered Greeting + Centered Composer) */
.main-pane.is-empty-thread .main-scroll {
  flex: 0 0 auto;
  margin-top: auto;
  overflow: visible;
  padding: 0 2.25rem 1.35rem;
}

.main-pane.is-empty-thread .prompt-dock {
  margin-bottom: auto;
  padding-top: 0;
}

.empty-thread-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 0;
}

.empty-state-title {
  font-size: clamp(1.55rem, 2.8vw, 1.95rem);
  font-weight: 500;
  letter-spacing: -0.025em;
  line-height: 1.25;
  color: var(--text-black);
}

/* Subtle Loading / Thinking Indicator */
.thinking-indicator {
  font-size: 0.86rem;
  color: var(--text-muted);
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.35rem 0;
}

.thinking-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--text-black);
  animation: pulseDot 1.1s infinite ease-in-out;
}

@keyframes pulseDot {
  0%, 100% { opacity: 0.25; transform: scale(0.9); }
  50% { opacity: 1; transform: scale(1.1); }
}

/* AI Settings Modal (antigravity.google inspired sculptural minimal dialog) */
.settings-modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(9, 9, 11, 0.32);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1.25rem;
}

.settings-modal-card {
  position: relative;
  width: 100%;
  max-width: 400px;
  background: #ffffff;
  border: 1px solid rgba(0, 0, 0, 0.08);
  border-radius: 24px;
  padding: 1.85rem 1.75rem 1.65rem;
  box-shadow: 0 24px 60px rgba(0, 0, 0, 0.12);
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.settings-modal-close {
  position: absolute;
  top: 1.05rem;
  right: 1.05rem;
  width: 32px;
  height: 32px;
  border-radius: 999px;
  color: var(--text-muted);
}

.settings-modal-close:hover {
  background: var(--bg-soft);
  color: var(--text-black);
}

.settings-modal-intro {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
  padding-right: 1.75rem;
}

.settings-modal-title {
  font-size: 1.25rem;
  font-weight: 500;
  letter-spacing: -0.025em;
  line-height: 1.2;
  color: var(--text-black);
}

.settings-modal-desc {
  font-size: 0.88rem;
  line-height: 1.55;
  color: var(--text-muted);
}

.settings-modal-form {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.settings-field {
  display: flex;
  flex-direction: column;
}

.settings-input {
  width: 100%;
  height: 46px;
  border: 1px solid var(--border-strong);
  background: var(--bg-subtle);
  border-radius: 14px;
  padding: 0 1rem;
  font-family: inherit;
  font-size: 0.9rem;
  color: var(--text-black);
  outline: none;
  transition: border-color 0.16s ease, background 0.16s ease, box-shadow 0.16s ease;
}

.settings-input:focus {
  background: #ffffff;
  border-color: var(--text-black);
  box-shadow: 0 0 0 3px rgba(15, 23, 42, 0.06);
}

.settings-key-masked {
  -webkit-text-security: disc;
  text-security: disc;
}

.settings-connected-view {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 0.85rem;
  padding: 0.65rem 0.5rem 0.25rem;
}

.settings-connected-icon {
  width: 48px;
  height: 48px;
  border-radius: 16px;
  background: var(--text-black);
  color: #ffffff;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.settings-connected-icon svg {
  width: 22px;
  height: 22px;
  stroke: currentColor;
  stroke-width: 2;
  fill: none;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.settings-connected-text {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.settings-connected-title {
  font-size: 1.15rem;
  font-weight: 500;
  letter-spacing: -0.02em;
  color: var(--text-black);
}

.settings-connected-sub {
  font-size: 0.86rem;
  color: var(--text-muted);
  line-height: 1.45;
}

.settings-feedback {
  font-size: 0.81rem;
  line-height: 1.45;
  padding: 0.6rem 0.85rem;
  border-radius: 12px;
  border: 1px solid var(--border-hairline);
  background: var(--bg-subtle);
  color: var(--text-muted);
}

.settings-feedback.is-error {
  background: var(--danger-bg);
  border-color: rgba(239, 68, 68, 0.25);
  color: var(--danger-text);
}

.chat-error-banner {
  background: var(--danger-bg);
  border: 1px solid rgba(239, 68, 68, 0.24);
  color: var(--danger-text);
  border-radius: 12px;
  padding: 0.75rem 1rem;
  font-size: 0.84rem;
  line-height: 1.5;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
}

.settings-modal-actions {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  width: 100%;
  margin-top: 0.15rem;
}

.settings-btn {
  flex: 1 1 0%;
  height: 44px;
  padding: 0 1rem;
  border-radius: 999px;
  font-size: 0.88rem;
  font-weight: 500;
  letter-spacing: -0.01em;
  justify-content: center;
}

.settings-btn-solid {
  background: var(--text-black);
  color: #ffffff;
  border: 1px solid var(--text-black);
}

.settings-btn-solid:hover {
  opacity: 0.88;
}

.settings-btn-outline {
  background: #ffffff;
  color: var(--text-black);
  border: 1px solid var(--border-strong);
}

.settings-btn-outline:hover {
  background: var(--bg-soft);
  border-color: rgba(0, 0, 0, 0.24);
}

.settings-btn-disconnect {
  background: var(--danger-bg);
  color: var(--danger-text);
  border: 1px solid rgba(239, 68, 68, 0.18);
}

.settings-btn-disconnect:hover {
  background: var(--danger-bg-hover);
}

/* Main Scrollable Canvas */
.main-scroll {
  flex: 1;
  overflow-y: auto;
  overflow-x: hidden;
  padding: 2rem 2.25rem 1.5rem;
}

.main-scroll::-webkit-scrollbar,
.bucket-thread::-webkit-scrollbar {
  width: 6px;
}

.main-scroll::-webkit-scrollbar-thumb,
.bucket-thread::-webkit-scrollbar-thumb {
  background: rgba(0, 0, 0, 0.14);
  border-radius: 999px;
}

.chat-stream {
  display: flex;
  flex-direction: column;
  gap: 1.75rem;
  /* Full reading width when no bucket is open */
  width: min(720px, 100%);
  margin: 0 auto;
  transition: width 0.42s var(--ease-smooth);
}

/* With the bucket open, use the width the half-pane allows (no sudden re-wrap on wide screens) */
.workspace-shell.has-open-bucket .chat-stream {
  width: min(720px, calc(50vw - 5.5rem));
}

.msg-card {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.msg-user {
  align-self: flex-end;
  background: var(--bg-soft);
  color: var(--text-black);
  border: 1px solid var(--border-hairline);
  padding: 0.7rem 1.05rem;
  border-radius: 16px;
  max-width: 82%;
  font-size: 0.94rem;
  line-height: 1.55;
}

.msg-assistant {
  background: transparent;
  line-height: 1.75;
  font-size: 0.98rem;
  color: var(--text-black);
}

.msg-body p,
.bucket-a p {
  margin-bottom: 0.85rem;
}

.msg-body p:last-child,
.bucket-a p:last-child {
  margin-bottom: 0;
}

.msg-heading {
  font-size: 1.02rem;
  font-weight: 700;
  color: var(--text-black);
  margin: 0.9rem 0 0.45rem;
  line-height: 1.35;
}

.msg-heading:first-child {
  margin-top: 0;
}

.msg-list {
  margin: 0.35rem 0 0.85rem 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.msg-list:last-child {
  margin-bottom: 0;
}

.inline-code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  font-size: 0.86em;
  background: var(--bg-soft);
  border: 1px solid var(--border-hairline);
  border-radius: 5px;
  padding: 0.1rem 0.35rem;
}

.msg-code-block {
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  font-size: 0.84rem;
  line-height: 1.55;
  background: var(--bg-subtle);
  border: 1px solid var(--border-hairline);
  border-radius: 10px;
  padding: 0.75rem 0.95rem;
  margin-bottom: 0.85rem;
  overflow-x: auto;
}

.msg-code-block:last-child {
  margin-bottom: 0;
}

sup,
sub {
  font-size: 0.74em;
  line-height: 0;
}

.msg-main-actions {
  margin-top: 0.45rem;
  display: flex;
  align-items: center;
}

/* Highlighted Anchor Phrase */
.concept-anchor {
  background: var(--anchor-bg);
  color: var(--text-black);
  border-bottom: 1.5px solid var(--anchor-border);
  padding: 0.06rem 0.34rem;
  border-radius: 5px;
  cursor: pointer;
  font-weight: 500;
  transition: background 0.16s ease, box-shadow 0.16s ease;
}

.concept-anchor:hover {
  background: var(--anchor-bg-hover);
}

.concept-anchor.active-anchor {
  background: var(--anchor-bg-hover);
  box-shadow: 0 0 0 2px rgba(217, 119, 6, 0.22);
}

.bucket-pill-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 0.68rem;
  font-weight: 600;
  background: var(--text-black);
  color: #ffffff;
  min-width: 18px;
  height: 18px;
  padding: 0 0.38rem;
  border-radius: 999px;
  margin-left: 0.32rem;
  vertical-align: middle;
  line-height: 1;
}

/* Collapsible "N Clarifications" Drawer Pill under Main Explanation */
.folded-buckets-group {
  margin-top: 0.85rem;
  display: flex;
  flex-direction: column;
}

.folded-group-toggle {
  align-self: flex-start;
  max-width: 100%;
  display: inline-flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.65rem;
  background: var(--bg-subtle);
  border: 1px solid var(--border-hairline);
  border-radius: 999px;
  padding: 0.38rem 0.75rem 0.38rem 0.85rem;
  font-family: inherit;
  font-size: 0.8rem;
  color: var(--text-muted);
  cursor: pointer;
  transition: background 0.16s ease, border-color 0.16s ease;
}

.folded-group-toggle:hover {
  background: var(--bg-soft);
  border-color: var(--border-strong);
}

.folded-group-meta {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  min-width: 0;
  overflow: hidden;
}

.folded-group-count {
  font-weight: 700;
  color: var(--text-black);
  white-space: nowrap;
}

.folded-group-dot {
  color: var(--text-light);
  flex-shrink: 0;
}

.folded-group-names {
  color: var(--text-muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.folded-group-chevron {
  width: 14px;
  height: 14px;
  stroke: var(--text-muted);
  stroke-width: 2.2;
  fill: none;
  stroke-linecap: round;
  stroke-linejoin: round;
  flex-shrink: 0;
  transition: transform 0.24s var(--ease-smooth);
}

.folded-buckets-group.is-expanded .folded-group-chevron {
  transform: rotate(180deg);
}

.folded-group-list {
  display: grid;
  grid-template-rows: 0fr;
  opacity: 0;
  transition: grid-template-rows 0.28s var(--ease-smooth), opacity 0.22s ease, margin-top 0.28s var(--ease-smooth);
  margin-top: 0;
}

.folded-buckets-group.is-expanded .folded-group-list {
  grid-template-rows: 1fr;
  opacity: 1;
  margin-top: 0.55rem;
}

.folded-group-list-inner {
  overflow: hidden;
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
}

.folded-summary-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  background: var(--bg-subtle);
  border: 1px solid var(--border-hairline);
  border-radius: 12px;
  padding: 0.7rem 0.95rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  cursor: pointer;
  transition: background 0.16s ease, border-color 0.16s ease, transform 0.16s ease;
}

.folded-summary-item strong {
  color: var(--text-black);
  font-weight: 600;
}

.folded-summary-item:hover {
  background: var(--bg-soft);
  border-color: var(--border-strong);
}

.folded-open-label {
  font-size: 0.76rem;
  font-weight: 600;
  color: var(--text-black);
  background: #ffffff;
  border: 1px solid var(--border-hairline);
  padding: 0.25rem 0.65rem;
  border-radius: 999px;
  white-space: nowrap;
}

/* Left Column Bottom Composer Dock */
.prompt-dock {
  padding: 0.5rem 2rem 1.25rem;
  flex-shrink: 0;
}

.prompt-dock-inner {
  width: min(720px, 100%);
  margin: 0 auto;
  transition: width 0.42s var(--ease-smooth);
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
}

.workspace-shell.has-open-bucket .prompt-dock-inner {
  width: min(720px, calc(50vw - 5.5rem));
}

.suggestion-chips {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  flex-wrap: nowrap;
  overflow-x: auto;
  scrollbar-width: none;
}

.suggestion-chips::-webkit-scrollbar {
  display: none;
}

.try-chip {
  background: var(--bg-subtle);
  border: 1px solid var(--border-hairline);
  border-radius: 999px;
  padding: 0.28rem 0.7rem;
  font-family: inherit;
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-muted);
  cursor: pointer;
  white-space: nowrap;
  flex-shrink: 0;
  transition: all 0.15s ease;
}

.try-chip:hover {
  background: var(--text-black);
  color: #ffffff;
  border-color: var(--text-black);
}

.prompt-composer {
  display: flex;
  align-items: flex-end;
  gap: 0.6rem;
  background: var(--bg-subtle);
  border: 1px solid var(--border-strong);
  border-radius: 16px;
  padding: 0.45rem 0.55rem 0.45rem 1.1rem;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.03);
  transition: border-color 0.18s ease, background 0.18s ease, box-shadow 0.18s ease;
}

.prompt-composer:focus-within {
  background: #ffffff;
  border-color: rgba(0, 0, 0, 0.28);
  box-shadow: 0 4px 18px rgba(0, 0, 0, 0.06);
}

.prompt-input {
  flex: 1;
  border: none;
  background: transparent;
  font-family: inherit;
  font-size: 0.93rem;
  line-height: 1.5;
  color: var(--text-black);
  outline: none;
  resize: none;
  overflow-y: hidden;
  max-height: 148px;
  padding: 0.28rem 0;
  display: block;
}

.prompt-submit {
  flex-shrink: 0;
}

/* Right Column: Full-Height Side Workbench (50% viewport width when open) */
.side-workbench {
  flex: 0 0 0%;
  width: 0%;
  height: 100vh;
  opacity: 0;
  pointer-events: none;
  background: var(--bg-canvas);
  padding: 0;
  overflow: hidden;
  transition:
    flex-basis 0.42s var(--ease-smooth),
    width 0.42s var(--ease-smooth),
    opacity 0.28s ease,
    padding 0.42s var(--ease-smooth);
}

.workspace-shell.has-open-bucket .side-workbench {
  flex: 0 0 50%;
  width: 50%;
  opacity: 1;
  pointer-events: auto;
  padding: 0.75rem 0.85rem 0.75rem 0.25rem;
}

/* Darker Modal Card with clean straight borders (no shadow) */
.side-workbench-card {
  width: 100%;
  height: 100%;
  min-width: 420px;
  background: #ececef;
  border: 1px solid rgba(0, 0, 0, 0.12);
  border-radius: 14px;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  box-shadow: none;
}

/* Sleek Single-Line Top Bar */
.sheet-grab-bar {
  display: none;
}

.bucket-header {
  height: 50px;
  padding: 0 0.85rem 0 1.2rem;
  border-bottom: 1px solid rgba(0, 0, 0, 0.08);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  flex-shrink: 0;
}

.bucket-header-title {
  display: flex;
  align-items: center;
  min-width: 0;
  font-size: 0.92rem;
}

.bucket-concept-name {
  font-weight: 700;
  color: var(--text-black);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.bucket-actions {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  flex-shrink: 0;
}

.btn-icon {
  width: 32px;
  height: 32px;
  padding: 0;
  border-radius: 8px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  border: 1px solid transparent;
  transition: background 0.15s ease, color 0.15s ease, transform 0.12s ease;
}

.btn-icon svg {
  width: 15px;
  height: 15px;
  stroke: currentColor;
  stroke-width: 2;
  fill: none;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.btn-icon-close {
  background: transparent;
  color: var(--text-black);
}

.btn-icon-close:hover {
  background: rgba(0, 0, 0, 0.07);
}

.btn-icon-close svg {
  width: 18px;
  height: 18px;
  stroke-width: 2.2;
}

/* Spacious Side Conversation Canvas */
.bucket-thread {
  flex: 1;
  overflow-y: auto;
  padding: 1.35rem 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 1.1rem;
}

/* Top-most Left Response Bubble for Summary */
.bucket-summary-bubble {
  align-self: flex-start;
  max-width: 86%;
  background: #ffffff;
  border: 1px solid rgba(0, 0, 0, 0.08);
  border-radius: 14px 14px 14px 4px;
  padding: 0.75rem 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.bucket-summary-label {
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-black);
}

.bucket-summary-bubble p {
  font-size: 0.86rem;
  line-height: 1.55;
  color: var(--text-black);
  font-weight: 500;
}

.bucket-qa-card {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.bucket-q {
  align-self: flex-end;
  background: var(--text-black);
  color: #ffffff;
  padding: 0.55rem 0.95rem;
  border-radius: 14px 14px 4px 14px;
  font-weight: 500;
  font-size: 0.87rem;
  line-height: 1.45;
  max-width: 85%;
}

.bucket-a {
  align-self: flex-start;
  background: rgba(255, 255, 255, 0.78);
  border: 1px solid rgba(0, 0, 0, 0.07);
  border-radius: 14px 14px 14px 4px;
  padding: 0.85rem 1.05rem;
  font-size: 0.91rem;
  line-height: 1.65;
  color: var(--text-black);
  max-width: 92%;
}

.bucket-card-footer {
  display: flex;
  align-items: center;
  justify-content: flex-start;
  margin-top: -0.25rem;
}

/* Dedicated Bucket Follow-Up Composer at Bottom of Right Pane */
.bucket-footer {
  padding: 0.75rem 1.25rem 1rem;
  background: transparent;
  flex-shrink: 0;
}

.bucket-form {
  display: flex;
  align-items: flex-end;
  gap: 0.5rem;
  background: #ffffff;
  border: 1px solid rgba(0, 0, 0, 0.14);
  border-radius: 14px;
  padding: 0.38rem 0.45rem 0.38rem 0.95rem;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.03);
  transition: border-color 0.16s ease, box-shadow 0.16s ease;
}

.bucket-form:focus-within {
  border-color: rgba(0, 0, 0, 0.3);
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.06);
}

.bucket-input {
  flex: 1;
  border: none;
  background: transparent;
  font-family: inherit;
  font-size: 0.88rem;
  line-height: 1.5;
  color: var(--text-black);
  outline: none;
  resize: none;
  overflow-y: hidden;
  max-height: 132px;
  padding: 0.25rem 0;
  display: block;
}

.bucket-submit {
  flex-shrink: 0;
}

/* Mobile & Narrow Screens: iOS-Style Peek Bottom Sheet + Native Document Pull-to-Refresh */
@media (max-width: 860px) {
  body {
    height: auto;
    min-height: 100dvh;
    overflow-x: hidden;
    overflow-y: auto;
    overscroll-behavior-y: auto;
  }

  .workspace-shell {
    position: relative;
    height: auto;
    min-height: 100dvh;
    overflow: visible;
  }

  .main-pane {
    height: auto;
    min-height: 100dvh;
  }

  /* Keep Main Chat 100% width with zero re-wrapping when sheet opens */
  .workspace-shell.has-open-bucket .main-pane {
    flex: 1 1 100%;
  }

  .workspace-shell.has-open-bucket .chat-stream,
  .workspace-shell.has-open-bucket .prompt-dock-inner {
    width: min(720px, 100%);
  }

  /* Subtle dim over the top peek area when bottom sheet is open */
  .main-pane::after {
    content: '';
    position: fixed;
    inset: 0;
    background: rgba(15, 23, 42, 0.22);
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.34s var(--ease-smooth);
    z-index: 20;
  }

  .workspace-shell.has-open-bucket .main-pane::after {
    opacity: 1;
  }

  .pane-topbar {
    position: sticky;
    top: 0;
    z-index: 15;
    background: var(--bg-canvas);
    height: 48px;
    padding: 0 1.15rem;
  }

  .main-scroll {
    flex: 1;
    overflow: visible;
    padding: 1rem 1.15rem 0.75rem;
  }

  .main-pane.is-empty-thread .main-scroll {
    flex: 0 0 auto;
    margin-top: auto;
    padding: 0 1.15rem 1.1rem;
  }

  .prompt-dock {
    position: sticky;
    bottom: 0;
    z-index: 15;
    padding: 0.4rem 1.15rem 0.85rem;
    background: var(--bg-canvas);
  }

  .main-pane.is-empty-thread .prompt-dock {
    position: static;
    margin-bottom: auto;
    padding: 0 1.15rem 2.5rem;
  }

  .suggestion-chips {
    padding-bottom: 0.15rem;
  }

  /* Transform Side Workbench into an iOS Bottom Sheet (78% height, 22% top peek) */
  .side-workbench,
  .workspace-shell.has-open-bucket .side-workbench {
    position: fixed;
    left: 0;
    right: 0;
    bottom: 0;
    width: 100%;
    height: 78vh;
    height: 78dvh;
    flex: none;
    padding: 0;
    background: transparent;
    z-index: 30;
    opacity: 1;
    transform: translateY(104%);
    pointer-events: none;
    transition: transform 0.42s cubic-bezier(0.32, 0.72, 0, 1);
  }

  .workspace-shell.has-open-bucket .side-workbench {
    transform: translateY(0);
    pointer-events: auto;
  }

  .side-workbench-card {
    min-width: 0;
    width: 100%;
    height: 100%;
    border-radius: 22px 22px 0 0;
    border-bottom: none;
    box-shadow: 0 -8px 30px rgba(0, 0, 0, 0.12);
  }

  /* iOS Grab Handle Pill at Top of Bottom Sheet */
  .sheet-grab-bar {
    display: flex;
    justify-content: center;
    padding: 0.65rem 0 0.25rem;
    flex-shrink: 0;
    cursor: grab;
    touch-action: none;
  }

  .sheet-grab-pill {
    width: 38px;
    height: 4.5px;
    border-radius: 999px;
    background: rgba(0, 0, 0, 0.2);
  }

  .bucket-header {
    height: 44px;
    padding: 0 0.75rem 0 1.15rem;
    touch-action: none;
  }

  .bucket-thread {
    padding: 1.1rem 1.15rem;
  }

  .bucket-footer {
    padding: 0.6rem 1rem 0.85rem;
  }
}