:root {
  --sidebar-w: 279px;
  --bg: #f1f5f9;
  --panel: #fff;
  --border: rgba(148, 163, 184, 0.28);
  --text: #0f172a;
  --muted: #64748b;
  --accent: #4f46e5;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: Inter, system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
}

.demo-top {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 10px 16px;
  background: rgba(255, 255, 255, 0.92);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(8px);
}

.demo-top h1 {
  margin: 0;
  font-size: 14px;
  font-weight: 700;
}

.demo-top p {
  margin: 2px 0 0;
  font-size: 12px;
  color: var(--muted);
}

.demo-top a {
  font-size: 12px;
  font-weight: 600;
  color: var(--accent);
  text-decoration: none;
}

.demo-stage {
  display: flex;
  justify-content: center;
  padding: 24px 16px 40px;
}

.sidebar-mock {
  width: var(--sidebar-w);
  height: min(720px, calc(100vh - 100px));
  display: flex;
  flex-direction: column;
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  background: var(--panel);
  box-shadow: 0 18px 40px rgba(15, 23, 42, 0.12);
}

.stack {
  font-size: 12px;
}

.stack-slab--agent {
  flex-shrink: 0;
  border-bottom: 1px solid var(--border);
}

.stack-toolbar {
  padding: 8px 10px 6px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.stack-row {
  display: flex;
  align-items: center;
  gap: 6px;
  min-width: 0;
}

.stack-row--agent {
  flex-wrap: nowrap;
}

.stack-row--view {
  flex-wrap: wrap;
}

.stack-select {
  flex: 1 1 auto;
  min-width: 0;
  height: 30px;
  padding: 0 8px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #fff;
  font: inherit;
  font-size: 11px;
  color: #334155;
}

.stack-btn {
  flex-shrink: 0;
  width: 30px;
  height: 30px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #fff;
  font: inherit;
  font-size: 14px;
  line-height: 1;
  cursor: pointer;
  color: #475569;
}

.stack-util-btns {
  display: flex;
  gap: 4px;
  flex-wrap: wrap;
}

.stack-util-btn {
  width: 26px;
  height: 26px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: #f8fafc;
  font-size: 10px;
  color: #64748b;
  cursor: default;
}

.stack-view-chips {
  display: none;
  flex: 1 1 100%;
  gap: 4px;
  flex-wrap: wrap;
}

.stack-view-chip {
  border: 1px solid var(--border);
  border-radius: 999px;
  background: #fff;
  padding: 3px 8px;
  font: inherit;
  font-size: 10px;
  font-weight: 600;
  color: #64748b;
  cursor: pointer;
}

.stack-view-chip.is-active {
  border-color: #818cf8;
  background: #eef2ff;
  color: #3730a3;
}

.stack-divider {
  height: 1px;
  background: var(--border);
}

.stack-avatar-block {
  padding: 8px 10px 10px;
}

.stack-avatar-preview {
  height: 88px;
  border-radius: 10px;
  background: linear-gradient(135deg, #c7d2fe 0%, #e9d5ff 55%, #fbcfe8 100%);
  border: 1px solid rgba(129, 140, 248, 0.35);
  margin-bottom: 8px;
}

.stack-note-toggle {
  display: flex;
  align-items: center;
  gap: 6px;
  width: 100%;
  padding: 6px 8px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #f8fafc;
  font: inherit;
  font-size: 11px;
  font-weight: 600;
  color: #475569;
  cursor: pointer;
  text-align: left;
}

.stack-note-chevron {
  font-size: 10px;
  color: #94a3b8;
}

.stack-slab--tools {
  flex-shrink: 0;
  padding: 6px 10px;
  border-bottom: 1px solid var(--border);
  background: #fafbfc;
}

.stack-tools-row {
  display: flex;
  align-items: center;
  gap: 4px;
  flex-wrap: wrap;
}

.stack-tool-btn {
  width: 30px;
  height: 30px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #fff;
  font-size: 14px;
  line-height: 1;
  cursor: pointer;
  color: #475569;
}

.stack-tool-btn.is-active {
  border-color: #818cf8;
  background: #eef2ff;
}

.stack-tool-btn--wide {
  width: auto;
  padding: 0 8px;
  font-size: 10px;
  font-weight: 600;
}

.stack-slab--menu {
  flex: 1;
  min-height: 0;
  display: flex;
  flex-direction: column;
}

.stack-before-tree {
  flex-shrink: 0;
  padding: 8px 10px 6px;
  border-bottom: 1px solid var(--border);
}

.stack-search {
  display: flex;
  align-items: center;
  gap: 6px;
  height: 30px;
  padding: 0 10px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #fff;
  color: #94a3b8;
  font-size: 11px;
}

.stack-tree {
  flex: 1;
  min-height: 0;
  overflow: auto;
  padding: 6px 8px 10px;
}

.stack-tree ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.stack-tree-branch > ul {
  padding-left: 14px;
}

.stack-tree-node {
  display: flex;
  align-items: center;
  gap: 4px;
  min-width: 0;
  padding: 3px 6px;
  border-radius: 6px;
  font-size: 11px;
  line-height: 1.35;
  color: #334155;
}

.stack-tree-node:hover {
  background: rgba(148, 163, 184, 0.12);
}

.stack-tree-node.is-active {
  background: #eef2ff;
  color: #312e81;
  font-weight: 600;
}

.stack-tree-toggle {
  width: 14px;
  border: 0;
  background: transparent;
  font-size: 9px;
  color: #64748b;
  cursor: pointer;
  padding: 0;
}

.stack-tree-label {
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.stack-tree-badge {
  flex-shrink: 0;
  margin-left: auto;
  font-size: 9px;
  color: #94a3b8;
}

.stack-tree-branch.is-collapsed > ul {
  display: none;
}

.stack-hint {
  flex-shrink: 0;
  padding: 6px 10px;
  border-top: 1px dashed var(--border);
  font-size: 10px;
  color: var(--muted);
  background: #f8fafc;
}

/* ── v01 current (default) ── */

.stack--v01 .stack-avatar-preview {
  display: block;
}

/* ── v02 compact ── */

.stack--v02 .stack-toolbar {
  gap: 4px;
  padding: 6px 8px;
}

.stack--v02 .stack-row--view .stack-select--view,
.stack--v02 .stack-util-btns {
  display: none;
}

.stack--v02 .stack-row--agent .stack-select--agent {
  font-size: 10px;
}

.stack--v02 .stack-avatar-preview {
  display: none;
}

.stack--v02 .stack-avatar-block {
  padding-top: 0;
}

.stack--v02 .stack-slab--tools {
  padding: 4px 8px;
}

.stack--v02 .stack-tool-btn {
  width: 28px;
  height: 28px;
}

/* ── v03 cards ── */

.stack--v03 {
  background: #e2e8f0;
  gap: 6px;
  padding: 6px;
  border: 0;
}

.stack--v03 .stack-slab--agent,
.stack--v03 .stack-slab--tools,
.stack--v03 .stack-slab--menu {
  border: 1px solid var(--border);
  border-radius: 10px;
  background: #fff;
  overflow: hidden;
}

.stack--v03 .stack-slab--menu {
  flex: 1;
}

.stack--v03 .stack-divider {
  display: none;
}

/* ── v04 unified ── */

.stack--v04 .stack-slab--agent,
.stack--v04 .stack-slab--tools,
.stack--v04 .stack-before-tree {
  border-bottom: 0;
}

.stack--v04 .stack-divider {
  display: none;
}

.stack--v04 .stack-toolbar,
.stack--v04 .stack-avatar-block,
.stack--v04 .stack-slab--tools,
.stack--v04 .stack-before-tree {
  padding-left: 12px;
  padding-right: 12px;
}

.stack--v04 .stack-slab--tools {
  background: transparent;
  padding-top: 0;
  padding-bottom: 4px;
}

/* ── v05 hero ── */

.stack--v05 .stack-slab--agent {
  position: relative;
  border-bottom: 0;
}

.stack--v05 .stack-toolbar {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 2;
  padding: 8px;
  background: linear-gradient(180deg, transparent, rgba(15, 23, 42, 0.72));
}

.stack--v05 .stack-select,
.stack--v05 .stack-btn {
  border-color: rgba(255, 255, 255, 0.35);
  background: rgba(255, 255, 255, 0.92);
}

.stack--v05 .stack-row--view {
  display: none;
}

.stack--v05 .stack-divider,
.stack--v05 .stack-note-toggle {
  display: none;
}

.stack--v05 .stack-avatar-block {
  padding: 0;
}

.stack--v05 .stack-avatar-preview {
  height: 148px;
  margin: 0;
  border-radius: 0;
  border: 0;
}

/* ── v06 chips ── */

.stack--v06 .stack-select--view {
  display: none;
}

.stack--v06 .stack-view-chips {
  display: flex;
}

.stack--v06 .stack-util-btns {
  display: none;
}

/* ── v07 merged tools ── */

.stack--v07 .stack-slab--tools {
  display: none;
}

.stack--v07 .stack-before-tree {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 8px 10px;
  border-bottom: 1px solid var(--border);
}

.stack--v07 .stack-search {
  flex: 1;
  min-width: 0;
}

.stack--v07 .stack-tools-inline {
  display: flex;
  gap: 4px;
}

.stack--v07 .stack-tools-inline .stack-tool-btn {
  width: 28px;
  height: 28px;
}

/* ── v08 split ── */

.stack--v08 {
  display: grid;
  grid-template-columns: 92px 1fr;
  grid-template-rows: auto 1fr;
  height: min(720px, calc(100vh - 100px));
}

.stack--v08 .stack-slab--agent {
  grid-column: 1;
  grid-row: 1 / span 2;
  border-right: 1px solid var(--border);
  border-bottom: 0;
}

.stack--v08 .stack-toolbar {
  padding: 8px 6px;
}

.stack--v08 .stack-row--view,
.stack--v08 .stack-divider,
.stack--v08 .stack-avatar-preview,
.stack--v08 .stack-note-toggle {
  display: none;
}

.stack--v08 .stack-select--agent {
  font-size: 9px;
  height: 26px;
  padding: 0 4px;
}

.stack--v08 .stack-btn--picker {
  width: 100%;
  margin-top: 4px;
}

.stack--v08 .stack-avatar-block {
  padding: 8px 6px;
}

.stack--v08 .stack-avatar-block::after {
  content: "Aya";
  display: block;
  text-align: center;
  font-size: 10px;
  font-weight: 700;
  color: #475569;
  margin-top: 6px;
}

.stack--v08 .stack-slab--tools {
  grid-column: 2;
  grid-row: 1;
}

.stack--v08 .stack-slab--menu {
  grid-column: 2;
  grid-row: 2;
  min-height: 0;
}

.stack--v08 .stack-hint {
  grid-column: 1 / -1;
}

/* ── v09 minimal ── */

.stack--v09 .stack-select,
.stack--v09 .stack-btn,
.stack--v09 .stack-tool-btn,
.stack--v09 .stack-note-toggle,
.stack--v09 .stack-search {
  border: 0;
  background: transparent;
  box-shadow: none;
}

.stack--v09 .stack-slab--agent,
.stack--v09 .stack-slab--tools,
.stack--v09 .stack-before-tree {
  border-bottom-color: rgba(148, 163, 184, 0.15);
}

.stack--v09 .stack-divider {
  display: none;
}

.stack--v09 .stack-avatar-preview {
  background: #f1f5f9;
  border: 0;
}

.stack--v09 .stack-tool-btn.is-active {
  background: rgba(99, 102, 241, 0.1);
}

/* ── v10 accent bands ── */

.stack--v10 .stack-slab--agent {
  border-bottom: 0;
  background: linear-gradient(135deg, #4f46e5 0%, #6366f1 55%, #818cf8 100%);
  color: #fff;
}

.stack--v10 .stack-select,
.stack--v10 .stack-btn {
  border-color: rgba(255, 255, 255, 0.35);
  background: rgba(255, 255, 255, 0.94);
}

.stack--v10 .stack-divider {
  background: rgba(255, 255, 255, 0.25);
}

.stack--v10 .stack-avatar-block {
  background: rgba(255, 255, 255, 0.08);
}

.stack--v10 .stack-note-toggle {
  border-color: rgba(255, 255, 255, 0.35);
  background: rgba(255, 255, 255, 0.12);
  color: #fff;
}

.stack--v10 .stack-slab--tools {
  background: linear-gradient(135deg, #64748b 0%, #78859a 55%, #94a3b8 100%);
  border-bottom: 0;
}

.stack--v10 .stack-tool-btn {
  border-color: rgba(255, 255, 255, 0.35);
  background: rgba(255, 255, 255, 0.9);
}

.stack--v10 .stack-tool-btn.is-active {
  background: #fff;
}

.stack-tools-inline {
  display: none;
}