diff --git a/.storybook/preview.jsx b/.storybook/preview.jsx
index 4e3f734fc6..878de70d71 100644
--- a/.storybook/preview.jsx
+++ b/.storybook/preview.jsx
@@ -2,7 +2,7 @@ import { withThemeByClassName } from "@storybook/addon-themes";
 import React, { useLayoutEffect } from "react";
 import darksideCss from "@navikt/ds-css/darkside/index.css?inline";
 import defaultCss from "@navikt/ds-css/index.css?inline";
-import { UNSAFE_AkselTheme } from "@navikt/ds-react/Provider";
+import { UNSAFE_AkselTheme } from "../@navikt/core/react/src/provider";
 import "./layout.css";
 
 export const parameters = {
diff --git a/@navikt/core/css/darkside/accordion.darkside.css b/@navikt/core/css/darkside/accordion.darkside.css
index b44af6e4eb..a5c9d3f369 100644
--- a/@navikt/core/css/darkside/accordion.darkside.css
+++ b/@navikt/core/css/darkside/accordion.darkside.css
@@ -1,198 +1,182 @@
-.navds-accordion {
-  --__ac-accordion-header-shadow-color: var(--ac-accordion-header-border, var(--a-border-divider));
-}
-
-/*************************
- * Header *
- *************************/
+/* ---------------------------- Accordion header ---------------------------- */
 .navds-accordion__header {
-  --__ac-accordion-header-shadow: inset 2px 0 0 0 var(--a-transparent), inset -2px 0 0 0 var(--a-transparent),
-    inset 0 2px 0 0 var(--__ac-accordion-header-shadow-color);
-
   width: 100%;
   display: flex;
   justify-content: flex-start;
   align-items: flex-start;
-  gap: var(--a-spacing-2);
-  padding: var(--a-spacing-3);
-  margin: 0;
+  gap: var(--ax-spacing-3);
+  padding: var(--ax-spacing-3);
   text-align: left;
-  background: var(--ac-accordion-header-bg, var(--a-surface-transparent));
   cursor: pointer;
   border: none;
   position: relative;
-  box-shadow: var(--__ac-accordion-header-shadow);
-  z-index: 1;
-}
+  border-radius: var(--ax-border-radius-large);
+  background: transparent;
+  color: var(--ax-text-accent);
 
-.navds-accordion__header:hover {
-  background-color: var(--ac-accordion-header-bg-hover, var(--a-surface-hover));
-  text-decoration: underline;
-  color: var(--ac-accordion-header-text-hover, inherit);
-}
+  > * {
+    font-weight: var(--ax-font-weight-regular);
+  }
 
-.navds-accordion--small .navds-accordion__header {
-  padding: var(--a-spacing-2) var(--a-spacing-3);
-}
+  @media (forced-colors: active) {
+    border: 1px solid buttonborder;
+    background-color: canvas;
+    color: canvastext;
+  }
 
-.navds-accordion--medium .navds-accordion__header {
-  padding: var(--a-spacing-3);
-}
+  &:hover {
+    background-color: var(--ax-bg-accent-hoverA);
+    color: var(--ax-text-accent-strong);
+
+    &::before,
+    &::after {
+      display: none;
+    }
+
+    > .navds-accordion__icon-wrapper {
+      background-color: var(--ax-bg-accent-strong-hover);
+      color: var(--ax-text-accent-contrast);
+    }
+
+    @media (forced-colors: active) {
+      background-color: canvas;
+      border: 1px solid highlight;
+      color: highlight;
+    }
+  }
 
-.navds-accordion--large .navds-accordion__header {
-  padding: var(--a-spacing-4) var(--a-spacing-3);
-}
+  &:focus-visible {
+    outline: 2px solid var(--ax-border-focus);
+    outline-offset: 2px;
+    z-index: 1;
 
-.navds-accordion__item:last-child > :where(.navds-accordion__header) {
-  box-shadow:
-    var(--__ac-accordion-header-shadow),
-    inset 0 -2px 0 0 var(--__ac-accordion-header-shadow-color);
+    &::before,
+    &::after {
+      display: none;
+    }
+  }
 }
 
-.navds-accordion__item:last-child:where(.navds-accordion__item--open) :where(.navds-accordion__header) {
-  box-shadow:
-    inset 2px 0 0 0 var(--a-transparent),
-    inset -2px 0 0 0 var(--a-transparent),
-    inset 0 2px 0 0 var(--a-transparent),
-    inset 0 2px 0 0 var(--__ac-accordion-header-shadow-color);
+.navds-accordion--small .navds-accordion__header {
+  padding-block: var(--a-spacing-2);
 }
 
-.navds-accordion__item:last-child:where(.navds-accordion__item--open) {
-  box-shadow:
-    inset 2px 0 0 0 var(--a-transparent),
-    inset -2px 0 0 0 var(--a-transparent),
-    inset 0 2px 0 0 var(--a-transparent),
-    inset 0 -2px 0 0 var(--__ac-accordion-header-shadow-color);
+.navds-accordion__header::before,
+.navds-accordion__header::after {
+  content: "";
+  display: block;
+  position: absolute;
+  top: 0;
+  left: 0;
+  right: 0;
+  width: 100%;
+  height: 1px;
+  background-color: var(--ax-border-subtleA);
 }
 
-.navds-accordion__item--open > :where(.navds-accordion__header) {
-  box-shadow: var(--__ac-accordion-header-shadow);
+.navds-accordion__item:last-child > .navds-accordion__content {
+  border-bottom: 1px solid transparent;
 }
 
-.navds-accordion__header:focus-visible {
-  outline: 2px solid transparent;
-  outline-offset: 3px;
-  box-shadow: var(--a-shadow-focus);
-  border-radius: var(--a-border-radius-large);
+.navds-accordion__header::after {
+  top: initial;
+  bottom: 0;
 }
 
-@supports not selector(:focus-visible) {
-  .navds-accordion__header:focus {
-    outline: none;
-    box-shadow: var(--a-shadow-focus);
-    border-radius: var(--a-border-radius-large);
-  }
+.navds-accordion__item[data-expanded="true"] > .navds-accordion__header::after,
+.navds-accordion__item:not(:last-child) > .navds-accordion__header::after {
+  display: none;
 }
 
-.navds-accordion__header-content {
-  overflow: hidden;
-  text-overflow: ellipsis;
+.navds-accordion__item[data-expanded="false"]:has(.navds-accordion__header:where(:hover, :focus-visible))
+  + .navds-accordion__item
+  > .navds-accordion__header::before {
+  display: none;
 }
 
-/*************************
- * Icon *
- *************************/
+/* ------------------------- Accordion chevron icon ------------------------- */
 .navds-accordion__icon-wrapper {
-  display: grid;
-  place-content: center;
-  border-radius: var(--a-border-radius-medium);
-  height: var(--a-spacing-6);
-  width: var(--a-spacing-6);
+  border-radius: var(--ax-border-radius-large);
+  width: 22px;
+  height: 22px;
   align-self: center;
-}
-
-.navds-accordion__header:hover > .navds-accordion__icon-wrapper {
-  background-color: var(--ac-accordion-header-icon-bg-hover, var(--a-surface-neutral-subtle-hover));
+  background-color: var(--ax-bg-accent-moderateA);
+  color: var(--ax-text-accent-strong);
 }
 
 .navds-accordion__header-chevron {
-  border-radius: var(--a-border-radius-medium);
-  font-size: 1.5rem;
-  height: 1.75rem;
+  height: inherit;
+  width: inherit;
   flex-shrink: 0;
-  transition: transform 150ms ease-in-out;
-  align-self: center;
+  transition: transform 250ms cubic-bezier(0.2, 0, 0, 1);
 }
 
-:where(.navds-accordion__header):hover > :where(.navds-accordion__icon-wrapper) > :where(.navds-accordion__header-chevron) {
-  transform: translateY(1px);
+.navds-accordion__item[data-expanded="true"] > .navds-accordion__header .navds-accordion__header-chevron {
+  transform: rotateX(-180deg);
 }
 
-.navds-accordion__item--open
-  > :where(.navds-accordion__header)
-  > :where(.navds-accordion__icon-wrapper)
-  > :where(.navds-accordion__header-chevron) {
-  transform: translateY(0) rotate(-180deg);
-}
-
-.navds-accordion__item--open
-  > :where(.navds-accordion__header):hover
-  > :where(.navds-accordion__icon-wrapper)
-  > :where(.navds-accordion__header-chevron) {
-  transform: translateY(-1px) rotate(-180deg);
-}
-
-/*************************
- * Variant/Default *
- *************************/
-.navds-accordion__item--open {
-  background-color: var(--ac-accordion-item-bg-open, var(--a-transparent));
-}
-
-/*************************
- * Variant/Neutral *
- *************************/
-.navds-accordion__item--open.navds-accordion__item--neutral {
-  background-color: var(--ac-accordion-neutral-item-bg-open, var(--a-surface-neutral-subtle));
-}
-
-/*************************
- * Content *
- *************************/
-
+/* ---------------------------- Accordion content --------------------------- */
 .navds-accordion__content {
-  padding: var(--a-spacing-1) var(--a-spacing-3) var(--a-spacing-5);
-  animation: fadeAccordionContent 250ms ease;
-}
-
-.navds-accordion--indent > :where(.navds-accordion__item) > :where(.navds-accordion__content) {
-  padding: var(--a-spacing-1) var(--a-spacing-3) var(--a-spacing-5) var(--a-spacing-11);
-}
+  --__acx-accordion-content-line-width: 2px;
 
-.navds-accordion__content--closed {
+  padding-inline: var(--ax-spacing-6) var(--ax-spacing-3);
   display: none;
+  overflow: hidden;
+  padding-block: 0;
+  max-height: 0;
+  border-color: transparent;
+  transition: all 250ms cubic-bezier(0.2, 0, 0, 1) allow-discrete;
+  animation: navds-accordion-content-animation 250ms cubic-bezier(0.2, 0, 0, 1);
 }
 
-.navds-accordion__item--no-animation :where(.navds-accordion__content) {
+.navds-accordion__item--no-animation {
   animation: none;
 }
 
-@keyframes fadeAccordionContent {
+@keyframes navds-accordion-content-animation {
   0% {
-    opacity: 0.25;
-    transform: translateY(-8px);
+    opacity: 0.01;
   }
 
-  40% {
-    opacity: 0.7;
+  20% {
+    opacity: 0.01;
   }
 
   100% {
     opacity: 1;
-    transform: translateY(0);
   }
 }
 
-@media (forced-colors: active) {
-  .navds-accordion__header {
-    border: 1px solid buttonborder;
-    background-color: canvas;
-    color: canvastext;
+.navds-accordion--indent > .navds-accordion__item > .navds-accordion__content {
+  padding-inline: var(--ax-spacing-6) var(--ax-spacing-3);
+}
+
+.navds-accordion--indent > .navds-accordion__item .navds-accordion__content-inner {
+  box-shadow: -2px 0 0 0 var(--ax-border-subtleA);
+  padding-block: var(--ax-spacing-2);
+
+  /* Aligns content with heading-section */
+  padding-inline: calc(var(--ax-spacing-5) + 2px) var(--ax-spacing-5);
+
+  @media (forced-colors: active) {
+    border-left: 1px solid canvastext;
   }
+}
 
-  .navds-accordion__header:hover {
-    background-color: canvas;
-    border: 1px solid highlight;
-    color: highlight;
+.navds-accordion__item[data-expanded="true"] > .navds-accordion__content {
+  display: block;
+  opacity: 1;
+  overflow: visible;
+  max-height: fit-content;
+  padding-block: var(--ax-spacing-2);
+  padding-block-end: var(--ax-spacing-6);
+  border-color: var(--ax-border-subtleA);
+}
+
+@starting-style {
+  .navds-accordion__item[data-expanded="true"]:not(.navds-accordion__item--no-animation) > .navds-accordion__content {
+    padding-block: 0;
+    max-height: 0;
+    border-color: transparent;
   }
 }
diff --git a/@navikt/core/react/src/accordion/Accordion.tsx b/@navikt/core/react/src/accordion/Accordion.tsx
index a6d4802b4b..024548df92 100644
--- a/@navikt/core/react/src/accordion/Accordion.tsx
+++ b/@navikt/core/react/src/accordion/Accordion.tsx
@@ -31,6 +31,7 @@ interface AccordionComponent
 
 export interface AccordionProps extends React.HTMLAttributes<HTMLDivElement> {
   /**
+   * @deprecated Prop will be removed in future versions. "default" will be the only variant.
    * @default "default"
    */
   variant?: "default" | "neutral";
diff --git a/@navikt/core/react/src/accordion/AccordionContent.tsx b/@navikt/core/react/src/accordion/AccordionContent.tsx
index 168958b7e3..30b125f0bb 100644
--- a/@navikt/core/react/src/accordion/AccordionContent.tsx
+++ b/@navikt/core/react/src/accordion/AccordionContent.tsx
@@ -1,5 +1,6 @@
 import cl from "clsx";
 import React, { forwardRef, useContext } from "react";
+import { UNSAFE_useAkselTheme } from "../provider";
 import { BodyLong } from "../typography";
 import { AccordionItemContext } from "./AccordionItem";
 
@@ -15,6 +16,8 @@ const AccordionContent = forwardRef<HTMLDivElement, AccordionContentProps>(
   ({ children, className, ...rest }, ref) => {
     const context = useContext(AccordionItemContext);
 
+    const themeContext = UNSAFE_useAkselTheme(false);
+
     if (context === null) {
       console.error(
         "<Accordion.Content> has to be used within an <Accordion.Item>",
@@ -38,7 +41,11 @@ const AccordionContent = forwardRef<HTMLDivElement, AccordionContentProps>(
           !context.open || undefined
         } /* Added to fix bug with Radio component, where label text inside a span sometimes is ignored by screen readers after hiding/displaying the RadioGroup inside an Accordion */
       >
-        {children}
+        {themeContext ? (
+          <div className="navds-accordion__content-inner">{children}</div>
+        ) : (
+          children
+        )}
       </BodyLong>
     );
   },
diff --git a/@navikt/core/react/src/accordion/AccordionHeader.tsx b/@navikt/core/react/src/accordion/AccordionHeader.tsx
index f3e73e6d89..98e26ae47f 100644
--- a/@navikt/core/react/src/accordion/AccordionHeader.tsx
+++ b/@navikt/core/react/src/accordion/AccordionHeader.tsx
@@ -1,6 +1,7 @@
 import cl from "clsx";
 import React, { forwardRef, useContext } from "react";
 import { ChevronDownIcon } from "@navikt/aksel-icons";
+import { UNSAFE_useAkselTheme } from "../provider";
 import { Heading } from "../typography";
 import { composeEventHandlers } from "../util/composeEventHandlers";
 import { AccordionContext } from "./AccordionContext";
@@ -19,6 +20,8 @@ const AccordionHeader = forwardRef<HTMLButtonElement, AccordionHeaderProps>(
     const itemContext = useContext(AccordionItemContext);
     const accordionContext = useContext(AccordionContext);
 
+    const themeContext = UNSAFE_useAkselTheme(false);
+
     if (itemContext === null) {
       console.error(
         "<Accordion.Header> has to be used within an <Accordion.Item>, which in turn must be within an <Accordion>",
@@ -26,6 +29,13 @@ const AccordionHeader = forwardRef<HTMLButtonElement, AccordionHeaderProps>(
       return null;
     }
 
+    let headingSize = accordionContext?.headingSize ?? "small";
+
+    if (themeContext) {
+      /* Fallback to "medium" Accordion-size if any other sizes are used */
+      headingSize = accordionContext?.size === "small" ? "xsmall" : "small";
+    }
+
     return (
       <button
         ref={ref}
@@ -42,7 +52,7 @@ const AccordionHeader = forwardRef<HTMLButtonElement, AccordionHeaderProps>(
           />
         </span>
         <Heading
-          size={accordionContext?.headingSize ?? "small"}
+          size={headingSize}
           as="span"
           className="navds-accordion__header-content"
         >
diff --git a/@navikt/core/react/src/accordion/AccordionItem.tsx b/@navikt/core/react/src/accordion/AccordionItem.tsx
index e049a9fa32..4434aa4a69 100644
--- a/@navikt/core/react/src/accordion/AccordionItem.tsx
+++ b/@navikt/core/react/src/accordion/AccordionItem.tsx
@@ -65,6 +65,7 @@ const AccordionItem = forwardRef<HTMLDivElement, AccordionItemProps>(
           "navds-accordion__item--neutral": context?.variant === "neutral",
           "navds-accordion__item--no-animation": !shouldAnimate.current,
         })}
+        data-expanded={_open}
         ref={ref}
         {...omit(rest, ["onClick"])}
       >