DEV Community: FSCSS

Did you know st-core.fscss doesn't need a runtime in production?

FSCSS — Wed, 08 Apr 2026 22:29:31 +0000

The <script> tag for FSCSS is a browser compiler- great for development, but optional for production.

You can compile your .fscss file down to plain .css ahead of time. The browser gets standard CSS. No runtime. No wait.

Compile with the CLI

npm install -g fscss
fscss style.fscss style.css

That's it. style.css is now pure clip-path math and CSS variables — no FSCSS runtime needed.

Prefer a GUI? There's a VS Code extension

FSCSS for VS Code gives you:

Syntax highlighting for .fscss files
Autocomplete + snippets
Auto Compile on Save — outputs to filename.fscss.css automatically
Command Palette: FSCSS: Compile

Why bother compiling?

	Dev (runtime)	Prod (compiled)
Setup	Drop in a `<script>` tag	One CLI command
Performance	JS parses before render	Instant CSS render
JS disabled	Chart won't show	Chart still works
Bundle size	Runtime included	Zero runtime cost

Repo → github.com/fscss-ttr/st-core.fscss ⭐ MIT

Building a Data-Driven Chart UI with Zero JavaScript (Pure CSS + FSCSS)

FSCSS — Wed, 01 Apr 2026 23:35:28 +0000

Most modern web charts rely on heavy JavaScript libraries. While powerful, they often come with a performance cost and complex integration steps.
What if you could build a fully styled, data-driven chart UI using Pure CSS?
By using FSCSS and its utility system, st-core (statistic core)_, we can transform raw data into visual interfaces directly within our stylesheets.

1. The Setup

First, include the FSCSS runtime and import the st-core helpers.

<script src="https://cdn.jsdelivr.net/npm/fscss@1.1.24/exec.min.js" async></script> 

<style>
@import((*) from st-core) 

/* Initialize design tokens, layout base, and colors */
@st-root() 
@st-container(body) 
</style>

2. Attaching the Components

st-core.fscss uses directive-like helpers to generate the complex logic needed for backgrounds, lines, and markers.

@st-chart-fill(.chart-fill)    /* Area under the line */
@st-chart-line(.chart-line)    /* The actual trend line */
@st-chart-dot(.chart-dot, 70, 60) /* Data point marker at x=70, y=60 */

3. Mapping Data to UI

This is where the magic happens. The @st-chart-points helper maps your numeric data points into CSS variables. These variables are then used to calculate a clip-path that draws the chart.

.chart {
  width: 300px;
  height: 400px;
  border-radius: 25px;
  border: 2px solid var(--st-accent);
  position: relative;
  overflow: hidden;
  background: var(--st-surface);

  /* The Data: These points define the shape of the graph */
  @st-chart-points(20, 25, 21, 37, 30, 60, 27, 50)
}

4. Customizing the Visuals

Because this is CSS, customization is trivial. You can use filters, transitions, and standard properties to polish the UI.

/* Add a glow to the line */
.chart-line {
  @st-chart-line-width(2px);
  filter: drop-shadow(0 0 8px var(--st-accent));
}

/* Style the tooltip and point */
.chart-dot {
  position: relative;
  --st-accent: #c4a8ff; /* Local theme override */
}

.chart-dot:after {
  content: attr(data-point); /* Pulls data from HTML attribute */
  background: var(--st-accent);
  padding: 6px 8px;
  border-radius: var(--st-radius-sm);
  /* ... positioning ... */
}

5. The Final HTML Structure

The HTML remains incredibly clean. No Canvas elements, no complex SVG strings—just a few semantic divs.

<div class="chart">
  <div class="chart-fill"></div>
  <div class="chart-line"></div>
  <div class="chart-dot" data-point="$405.67"></div>
</div>

Why This Matters

Zero JS Overhead: The browser handles the rendering logic via CSS variables and clip-paths.
Declarative Data: You define data where you define your styles.
Fully Themeable: Since it uses CSS variables (--st-accent, etc.), switching to dark mode or changing brand colors is instantaneous. This approach shifts the paradigm: CSS isn't just styling the UI, it’s generating the UI from data.

Check out the project here: st-core on GitHub

FSCSS Toast System (Dynamic UI Without Repetition)

FSCSS — Sun, 22 Mar 2026 17:39:25 +0000

A clean, scalable toast/notification system built with FSCSS using events + arrays + dynamic selectors.

No repeated classes. No manual variants.
Just structured, reusable styling.

Features

Dynamic toast types (success, error, warning, info)
Centralized color logic using @event
Auto-generated class variants with @arr
Clean and scalable structure
Modern UI styling (glass + soft colors)

Define Toast Color Logic

@event toast-color(type){

if type:success{
  return: #38d9a9;
}

el-if type:error{
  return: #ff6b6b;
}

el-if type:warning{
  return: #f7b267;
}

el{
  return: #74c0fc;
}

}

This acts like a function:

type → color

Base Toast Component

.toast{
  padding: 12px 16px;
  border-radius: 10px;
  color: #fff;
  font-size: 14px;

  background: rgba(255,255,255,0.05);
  backdrop-filter: blur(8px);

  border-left: 4px solid currentColor;

  display: flex;
  gap: 10px;
  align-items: center;

  min-width: 220px;
}

Generate Toast Variants

@arr toast-types[success,error,warning,info]
@arr i[1,2,3,4]

.toast-@arr.toast-types[@arr.i[]]{

  $type: @arr.toast-types[@arr.i[]];

  color: @event.toast-color($type);
}

💡 Why the Index Mapping?

FSCSS currently resolves:

Selector → index ("1, 2, 3...")
Value → actual array value ("success, error...")

So we map them together:

index → value → selector

Result:

.toast-success { color: ... }
.toast-error { color: ... }

Usage

<div class="toast toast-success">Operation successful</div>

<div class="toast toast-error">Something went wrong</div>

<div class="toast toast-warning">Check your input</div>

<div class="toast toast-info">New update available</div>

✨ Optional: Add Icons

<div class="toast toast-success">✔ Operation successful</div>
<div class="toast toast-error">✖ Something went wrong</div>
<div class="toast toast-warning">⚠ Check your input</div>
<div class="toast toast-info">ℹ New update available</div>

🔥 How It Works

Flow:

Class → Array Mapping → Event Logic → Final Style

Example:

toast-success
→ mapped to "success"
→ passed into @event
→ returns color
→ applied to UI

Why This Pattern Matters

Avoids repetitive CSS
Centralizes UI logic
Scales easily as types grow
Keeps styling consistent

Takeaway

This approach shows how FSCSS can:

Handle UI state
Generate variants automatically
Apply logic inside styling

Without relying on JavaScript.

Next Ideas

Add animations (slide-in, fade)
Create stacked notifications (top-right)
Build theme variations (dark/light)
Auto-inject icons via "@event"

Clean. Scalable. Powerful.

Welcome to structured CSS ❤️

FSCSS tutorial Follow

Figured Shorthand Cascading Style Sheet

⚡ Creating Custom Functions in FSCSS (Yes, CSS Can Do This)

FSCSS — Fri, 20 Mar 2026 16:24:13 +0000

One thing about FSCSS is that you can define your own functions… inside your styles. Here’s a simple example of how that works. 👇

Custom randint Function

@define randint(array){
@random(@use(array)) 
}

What this function does:

Takes an array as an argument.
Returns a random value directly from that array.

Step 1: Defining Arrays
First, we set up our possible values:

@arr sizes[ 100px, 150px, 200px ]

Step 2: Using the Function
We call our custom function and assign it to a variable:

$height: @randint(@arr.sizes);

Now $height dynamically becomes either 100px, 150px, or 200px (randomly selected at compile).

Why This Is Interesting

Reusable Logic: You can create complex logic once and use it across your entire design system.
Dynamic Design Systems: Build layouts that feel organic and varied rather than static and repetitive.

Example Usage

Applying that logic to a class is straightforward:

.box { 
  height: $height; 
  width: $height; 
  background: #2c5364; 
}

Every compile can produce a slightly different UI!

https://www.npmjs.com/package/fscss

FSCSS Import System You Actually Wanted

FSCSS — Tue, 10 Mar 2026 15:09:22 +0000

FSCSS v1.1.16+: Import System

JavaScript-Style Imports

@import((
flex-center,
flex-wrap, 
flex-x
) from flex-control)
@import((
circle-progress as clp,
progress-range as pr,
progress-root as p-root
) from circle-progress)
@import((*) from st-core)

@p-root() 
@clp(.progress)
.p-72{
  @pr(72) 
}
.container {
  @flex-center()
}

Named imports. Aliases.

5 Ways to Import

Named imports

@import((flex-x, flex-center) from flex-control)

Aliases (when names clash)

@import((circle-progress as cp) from circle-progress)

Everything (when you're lazy)

@import((*) from themes)

Remote (CDN friendly)

@import((btn) from "https://cdn.example/buttons.fscss")

Built-in libs (no quotes needed)

@import((*) from icon-mask)

Also: It's Faster Now

v1.1.16+ CDN loads quicker than older versions.

The Error Messages Actually Make Sense

@import((* as all) from "style.fscss")
// Warning: syntax error at @import((* as all) from "style.fscss"): unexpected *

No more cryptic parser errors at 2am.

Same modular architecture. Way less noise.

👉 https://github.com/fscss-ttr/fscss-modules/

how it feels when simple code yields impressive results?

FSCSS — Thu, 26 Feb 2026 23:04:46 +0000

You ever write something small…

Almost too simple…
Then you refresh the browser and just stare at it like
“Wait… I built this?” 😅

That’s the feeling.

Today I was playing with FSCSS and its simple plugin system, nothing complex, nothing heavy, just clean structure and small utilities working together.

And somehow…
It turns into a clean, responsive landing page.
No bloated configs.
Just focused structure.

FSCSS plugs → simple syntax → real UI.

Here’s a small example landing page built using FSCSS:

Version: 1.1.13
It’s simple.

But sometimes simple becomes powerful when it’s reusable.

That’s what I love about building tools.
You don’t always need 10,000 lines of code to create impact.

Sometimes you just need the right abstraction.
FSCSS keeps evolving, small, practical, useful.

And honestly?

Create Dynamic Shapes with FSCSS: A Quick Guide for Devs

FSCSS — Sat, 06 Sep 2025 10:37:38 +0000

Create Dynamic Shapes with FSCSS

If you’re looking to add some flair to your web projects, this FSCSS-powered shape generator is a lightweight way to create dynamic, colorful shapes with minimal code. Let’s dive into how it works and why it’s a neat tool for developers.

🔹 The Code

Here’s the complete snippet to generate 10 unique shapes with FSCSS:

<!-- Container for shapes -->
<section class="shapes" id="shapes"></section>

<style>
  /* Import FSCSS initialization and themes */
  @import(exec(_init themes))

  /* Define arrays for shapes and colors */
  @arr list[cross, star, diamond, cloud, teardrop, triangle, hexagon, trapeziod, crescent, arrow, square]
  @arr colors[red, blue, green, orange, purple, pink, brown, teal, gold, violet, gray]

  /* Style shapes using arrays */
  .shape:nth-child(@arr.list[]){
    %2(width, height [: 100px;])
    clip-path: @event.shape(@arr.list[]);
  }
  .shape:nth-child(@arr.colors[]){
    background: @arr.colors[];
    display: inline-block;
  }
</style>

<script>
  // Dynamically generate 10 shape divs
  const shapeContainer = document.getElementById("shapes");
  for (let i = 0; i < 10; i++) {
    const shape = document.createElement("div");
    shape.className = "shape";
    shapeContainer.appendChild(shape);
  }
</script>

<!-- FSCSS CDN -->
<script src="https://cdn.jsdelivr.net/npm/fscss@1.1.6" async></script>

🚀 Why It’s Cool

FSCSS Magic

→ The @arr and @event directives let you loop through shapes and colors effortlessly, reducing repetitive CSS.

Dynamic & Scalable

→ The JavaScript loop creates

s on the fly, and FSCSS applies unique shapes and colors based on array indices.

Lightweight

→ Minimal code for a visually engaging result, perfect for prototypes or creative UI elements.

⚙️ How It Works

HTML → A simple acts as the container for dynamically generated shapes.
FSCSS → Uses arrays (list for shapes, colors for backgrounds) and the @event.shape function imported to apply clip-path styles dynamically.
JavaScript → Creates 10
elements with the shape class, appended to the container.
Styling → Each shape gets a unique clip-path and color, displayed inline for a grid-like effect.

🎨 Try It Out

Drop this code into your HTML, ensure the FSCSS library is loaded, and watch colorful shapes come to life!

It’s great for:

UI experiments
Loading animations
Interactive backgrounds

📚 Learn More

Check out the FSCSS for more on @arr, @event and much more.
Share your tweaks or use cases in the comments! 🚀

Ditch the Repetition! Introducing @arr for Smart CSS with FSCSS

FSCSS — Thu, 31 Jul 2025 19:51:02 +0000

Hey everyone! 👋 Ever find yourself writing the same CSS properties over and over for different elements? Or manually creating nth-child rules for a series of items? There's a smarter way!

I wanted to share a super-handy feature from FSCSS that's a game-changer for writing clean, efficient styles: the @arr array declaration.

What is `@arr`?

It's a simple, powerful way to declare and reuse lists of values directly in your CSS. Think of it as a variable for a series of values—perfect for colors, spacings, font stacks, or any repeatable pattern.

🔧 The Basic Syntax
Declaring an array is as simple as:

@arr(arrayName[value1, value2, value3,...])

You can then use it in some ways:

@arr.arrayName[]: Iterates through the values, perfect for applying a different value to each element in a sequence.
@arr.arrayName(separator): Expands all values at once, great for creating a single string like a font stack or a list of properties.
@rr.arrayName[index], 1-Indexed: Access begins from index [1], not [0].FSCSS arrays are 1-indexed Accessing out-of-bound indexes returns undefined

Let's dive into some examples to see how this works in practice.

🎨 Example 1: Sequential Styling
Imagine you have a list and want to give each item a different color without writing a separate rule for each one.

Before @arr:

ul li:nth-child(1) {
  color: red;
}
ul li:nth-child(2) {
  color: green;
}
ul li:nth-child(3) {
  color: blue;
}

With @arr:
First, declare your color array:

@arr(colors[red, green, blue])

Then, use the [] syntax to iterate through it with your selector:

ul li:nth-child(@arr.colors[]) {
  background-color: @arr.colors[];
}

Result:

The first li gets background-color: red;
The second gets background-color: green;
The third gets background-color: blue;

So clean! ✨

🖋️ Example 2: Creating a Font Stack
This is perfect for consolidating fallback fonts into a single, reusable variable.

Declare your font array:

@arr(fonts[Arial, 'Helvetica Neue', sans-serif])

Then, use the () syntax to expand all values into a single property:

body {
  font-family: @arr.fonts(,);
}

Result:

font-family: Arial, 'Helvetica Neue', sans-serif;

No more re-typing that long list of fonts!

📏 Example 3: Dynamic CSS with Prefixes
You can even add custom prefixes and suffixes when you expand an array, which is great for generating dynamic properties.

Declare a margins array:

@arr(margins[10px, 20px, 30px])

Use the () syntax with a custom prefix margin::

div {
  content: "margin: @arr.margins(;margin: );";
}

Result:

content: "margin: 10px; margin: 20px; margin: 30px;";

This is a powerful pattern for generating responsive units or dynamic classes.

✨ Why This Matters

DRY (Don't Repeat Yourself): Define your values once and reuse them everywhere.
Maintainability: Need to change a color or a font? Update the array declaration, and it's changed everywhere.
Readability: Your CSS becomes much cleaner and easier to understand.
Automation: @arr handles the repetition for you, saving you time and effort.

If you're using FSCSS, give @arr a try—it'll simplify your workflow and make your stylesheets much smarter.

learn more about FSCSS

What are your favorite ways to use arrays in your CSS

ANIMATION SHORTHAND FSCSS

FSCSS — Sat, 25 Jan 2025 22:33:39 +0000

FSCSS $(@keyframes ...) method

FSCSS $(@keyframes...) method

FSCSS — Sat, 25 Jan 2025 07:32:51 +0000

FSCSS $() method,
Syntax: $(@keyframes...)
Parameters: $(@keyframes animation-name, selectors &[animation settings])

CSS moon night

FSCSS — Thu, 23 Jan 2025 08:08:13 +0000

HTML AND CSS MOON NIGHT EFFECT

CSS Background Shake Animation

FSCSS — Tue, 31 Dec 2024 07:27:54 +0000

ln.run

DEV Community: FSCSS

Did you know st-core.fscss doesn't need a runtime in production?

Compile with the CLI

Prefer a GUI? There's a VS Code extension

Why bother compiling?

Building a Data-Driven Chart UI with Zero JavaScript (Pure CSS + FSCSS)

1. The Setup

2. Attaching the Components

3. Mapping Data to UI

4. Customizing the Visuals

5. The Final HTML Structure

Why This Matters

FSCSS Toast System (Dynamic UI Without Repetition)

Features

Define Toast Color Logic

Base Toast Component

Generate Toast Variants

Usage

✨ Optional: Add Icons

🔥 How It Works

Why This Pattern Matters

Takeaway

Next Ideas

FSCSS tutorial Follow

⚡ Creating Custom Functions in FSCSS (Yes, CSS Can Do This)

Custom randint Function

Why This Is Interesting

Example Usage

FSCSS Import System You Actually Wanted

5 Ways to Import

No more cryptic parser errors at 2am.

👉 https://github.com/fscss-ttr/fscss-modules/

how it feels when simple code yields impressive results?

Create Dynamic Shapes with FSCSS: A Quick Guide for Devs

Create Dynamic Shapes with FSCSS

🔹 The Code

🚀 Why It’s Cool

FSCSS Magic

Dynamic & Scalable

Lightweight

⚙️ How It Works

🎨 Try It Out

📚 Learn More

Ditch the Repetition! Introducing @arr for Smart CSS with FSCSS

What is @arr?

learn more about FSCSS

ANIMATION SHORTHAND FSCSS

FSCSS $(@keyframes...) method

CSS moon night

CSS Background Shake Animation

What is `@arr`?