Theming

Svelte Flow comes with minimal default styles and was designed to be fully customizable. Many of our users fully transform the look and feel of Svelte Flow to match their own brand or design system. This guide will introduce you to the different ways you can customize Svelte Flow’s appearance.

Default styles

Svelte Flow’s default styles are enough to get going with the built-in nodes. They provide some sensible defaults for styles like padding, border radius, and animated edges. You can see what they look like below:

import '@xyflow/svelte/dist/style.css';

Base styles

If you just want to load the very basic styles that are necessary for Svelte Flow to work, you can import the base styles instead:

import '@xyflow/svelte/dist/base.css';

Customization

There are different ways how you can customize the appearance of Svelte Flow:

• Work with scoped CSS within your custom nodes and edges
• Override the built-in classes with custom CSS
• Override the CSS variables Svelte Flow uses
• Pass inline styles through style props

Working with built-in classes

If you want to override the default styles, you can do so by overriding the built-in CSS classes. You can find a list of all the classes used by Svelte Flow below:

Built in dark and light mode

You can choose one of the built-in color modes by using the colorMode prop (‘dark’, ‘light’ or ‘system’) as seen in the dark mode example.

import { SvelteFlow } from '@xyflow/svelte';
 
<SvelteFlow colorMode="dark" nodes={[...]} edges={[...]} />

When you use the colorMode prop, Svelte Flow adds a class to the root element (.svelte-flow) that you can use to style your flow based on the color mode:

.dark .svelte-flow__node {
  background: #777;
  color: white;
}
 
.light .svelte-flow__node {
  background: white;
  color: #111;
}

CSS variables

If you don’t want to replace the default styles entirely but just want to tweak the overall look and feel, you can override some of the CSS variables we use throughout the library.

These variables are mostly self-explanatory. Below is a table of all the variables you might want to tweak and their default values for reference:

These variables are used to define the defaults for the various elements of Svelte Flow. This means they can still be overridden by inline styles or custom classes on a per-element basis. If you want to override a variable, you can do so by adding:

.svelte-flow {
  --xy-node-background-color-default: #ff5050;
}

TailwindCSS

Custom nodes and edges are just Svelte components, and you can use any styling solution you’d like to style them. For example, you might want to use Tailwind  to style your nodes:

<script lang="ts">
  import { Handle, Position, type NodeProps } from '@xyflow/svelte';
 
  let { data }: NodeProps = $props();
</script>
 
<div class="px-4 py-2 shadow-md rounded-md bg-background border-2 border-stone-400">
  <div class="flex">
    <div class="rounded-full w-12 h-12 flex justify-center items-center bg-card">
      {data.emoji}
    </div>
    <div class="ml-2">
      <div class="text-lg font-bold">{data.name}</div>
      <div class="text-gray-500">{data.job}</div>
    </div>
  </div>
  <Handle
    type="target"
    position={Position.Top}
    class="w-16 !bg-teal-500 rounded-none border-none"
  />
  <Handle
    type="source"
    position={Position.Bottom}
    class="w-16 !bg-teal-500 rounded-none border-none"
  />
</div>

import '@xyflow/svelte/dist/style.css';
import 'tailwind.css';

For a complete example of using Tailwind with Svelte Flow, check out the tailwind example!