diff --git a/packages/ui/src/components/accordion.css b/packages/ui/src/components/accordion.css
index 7bf287fe54..9763298981 100644
--- a/packages/ui/src/components/accordion.css
+++ b/packages/ui/src/components/accordion.css
@@ -36,7 +36,9 @@
         border-radius: var(--radius-md);
         overflow: clip;
         color: var(--text-strong);
-        transition: background-color 0.15s ease;
+        transition-property: background-color, border-color;
+        transition-duration: var(--transition-duration);
+        transition-timing-function: var(--transition-easing);
 
         /* text-12-regular */
         font-family: var(--font-family-sans);
@@ -58,6 +60,16 @@
       }
     }
 
+    [data-slot="accordion-arrow"] {
+      flex-shrink: 0;
+      width: 16px;
+      height: 16px;
+      display: flex;
+      align-items: center;
+      justify-content: center;
+      color: var(--text-weak);
+    }
+
     &[data-expanded] {
       [data-slot="accordion-trigger"] {
         border-bottom-left-radius: 0;
@@ -69,30 +81,29 @@
         border-top: none;
         border-bottom-left-radius: var(--radius-md);
         border-bottom-right-radius: var(--radius-md);
+        height: auto;
       }
     }
 
     [data-slot="accordion-content"] {
-      overflow: hidden;
+      display: grid;
+      grid-template-rows: 0fr;
+      transition-property: grid-template-rows, opacity;
+      transition-duration: var(--transition-duration);
+      transition-timing-function: var(--transition-easing);
       width: 100%;
+
+      > * {
+        overflow: hidden;
+      }
+
+      &[data-expanded] {
+        grid-template-rows: 1fr;
+      }
+
+      &[data-closed] {
+        grid-template-rows: 0fr;
+      }
     }
   }
 }
-
-@keyframes slideDown {
-  from {
-    height: 0;
-  }
-  to {
-    height: var(--kb-accordion-content-height);
-  }
-}
-
-@keyframes slideUp {
-  from {
-    height: var(--kb-accordion-content-height);
-  }
-  to {
-    height: 0;
-  }
-}
diff --git a/packages/ui/src/components/accordion.tsx b/packages/ui/src/components/accordion.tsx
index 535d38e3d0..e30be95e05 100644
--- a/packages/ui/src/components/accordion.tsx
+++ b/packages/ui/src/components/accordion.tsx
@@ -1,6 +1,7 @@
 import { Accordion as Kobalte } from "@kobalte/core/accordion"
-import { splitProps } from "solid-js"
+import { Accessor, createContext, splitProps, useContext } from "solid-js"
 import type { ComponentProps, ParentProps } from "solid-js"
+import { MorphChevron } from "./morph-chevron"
 
 export interface AccordionProps extends ComponentProps<typeof Kobalte> {}
 export interface AccordionItemProps extends ComponentProps<typeof Kobalte.Item> {}
@@ -8,6 +9,8 @@ export interface AccordionHeaderProps extends ComponentProps<typeof Kobalte.Head
 export interface AccordionTriggerProps extends ComponentProps<typeof Kobalte.Trigger> {}
 export interface AccordionContentProps extends ComponentProps<typeof Kobalte.Content> {}
 
+const AccordionItemContext = createContext<Accessor<boolean>>()
+
 function AccordionRoot(props: AccordionProps) {
   const [split, rest] = splitProps(props, ["class", "classList"])
   return (
@@ -22,17 +25,19 @@ function AccordionRoot(props: AccordionProps) {
   )
 }
 
-function AccordionItem(props: AccordionItemProps) {
-  const [split, rest] = splitProps(props, ["class", "classList"])
+function AccordionItem(props: AccordionItemProps & { expanded?: boolean }) {
+  const [split, rest] = splitProps(props, ["class", "classList", "expanded"])
   return (
-    <Kobalte.Item
-      {...rest}
-      data-slot="accordion-item"
-      classList={{
-        ...(split.classList ?? {}),
-        [split.class ?? ""]: !!split.class,
-      }}
-    />
+    <AccordionItemContext.Provider value={() => split.expanded ?? false}>
+      <Kobalte.Item
+        {...rest}
+        data-slot="accordion-item"
+        classList={{
+          ...(split.classList ?? {}),
+          [split.class ?? ""]: !!split.class,
+        }}
+      />
+    </AccordionItemContext.Provider>
   )
 }
 
@@ -84,9 +89,25 @@ function AccordionContent(props: ParentProps<AccordionContentProps>) {
   )
 }
 
+export interface AccordionArrowProps extends ComponentProps<"div"> {
+  expanded?: boolean
+}
+
+function AccordionArrow(props: AccordionArrowProps = {}) {
+  const [local, rest] = splitProps(props, ["expanded"])
+  const contextExpanded = useContext(AccordionItemContext)
+  const isExpanded = () => local.expanded ?? contextExpanded?.() ?? false
+  return (
+    <div data-slot="accordion-arrow" {...rest}>
+      <MorphChevron expanded={isExpanded()} />
+    </div>
+  )
+}
+
 export const Accordion = Object.assign(AccordionRoot, {
   Item: AccordionItem,
   Header: AccordionHeader,
   Trigger: AccordionTrigger,
   Content: AccordionContent,
+  Arrow: AccordionArrow,
 })
diff --git a/packages/ui/src/components/session-turn.css b/packages/ui/src/components/session-turn.css
index bf143cd4fd..c8372d32e8 100644
--- a/packages/ui/src/components/session-turn.css
+++ b/packages/ui/src/components/session-turn.css
@@ -106,10 +106,11 @@
 
   [data-component="user-message"] [data-slot="user-message-text"] {
     max-height: var(--user-message-collapsed-height, 64px);
+    transition: max-height 200ms cubic-bezier(0.25, 0, 0.5, 1);
   }
 
   [data-component="user-message"][data-expanded="true"] [data-slot="user-message-text"] {
-    max-height: none;
+    max-height: 2000px;
   }
 
   [data-component="user-message"][data-can-expand="true"] [data-slot="user-message-text"] {
@@ -141,17 +142,6 @@
     background: transparent;
     cursor: pointer;
     color: var(--text-weak);
-
-    [data-slot="icon-svg"] {
-      transition: transform 0.15s ease;
-    }
-  }
-
-  [data-component="user-message"][data-expanded="true"]
-    [data-slot="user-message-text"]
-    [data-slot="user-message-expand"]
-    [data-slot="icon-svg"] {
-    transform: rotate(180deg);
   }
 
   [data-component="user-message"] [data-slot="user-message-text"] [data-slot="user-message-expand"]:hover {
@@ -457,6 +447,7 @@
     gap: 16px;
     align-items: center;
     justify-content: flex-end;
+    color: var(--icon-base);
   }
 
   [data-slot="session-turn-accordion-content"] {
diff --git a/packages/ui/src/components/session-turn.tsx b/packages/ui/src/components/session-turn.tsx
index fe53c0939c..fc0a9f7192 100644
--- a/packages/ui/src/components/session-turn.tsx
+++ b/packages/ui/src/components/session-turn.tsx
@@ -548,7 +548,7 @@ export function SessionTurn(
                             data-slot="session-turn-collapsible-trigger-content"
                             variant="ghost"
                             size="small"
-                            onClick={props.onStepsExpandedToggle ?? (() => {})}
+                            onClick={props.onStepsExpandedToggle ?? (() => { })}
                             aria-expanded={props.stepsExpanded}
                           >
                             <Switch>
diff --git a/packages/ui/src/styles/index.css b/packages/ui/src/styles/index.css
index 3ed0310ef2..7c8548734d 100644
--- a/packages/ui/src/styles/index.css
+++ b/packages/ui/src/styles/index.css
@@ -33,8 +33,10 @@
 @import "../components/markdown.css" layer(components);
 @import "../components/message-part.css" layer(components);
 @import "../components/message-nav.css" layer(components);
+@import "../components/morph-chevron.css" layer(components);
 @import "../components/popover.css" layer(components);
 @import "../components/progress-circle.css" layer(components);
+@import "../components/reasoning-icon.css" layer(components);
 @import "../components/radio-group.css" layer(components);
 @import "../components/resize-handle.css" layer(components);
 @import "../components/select.css" layer(components);