Pen Settings

HTML

About HTML Preprocessors

HTML preprocessors can make writing HTML more powerful or convenient. For instance, Markdown is designed to be easier to write and read for text documents and you could write a loop in Pug.

Learn more · Versions

Adding Classes

In CodePen, whatever you write in the HTML editor is what goes within the <body> tags in a basic HTML5 template. So you don't have access to higher-up elements like the <html> tag. If you want to add classes there that can affect the whole document, this is the place to do it.

About the <head>

In CodePen, whatever you write in the HTML editor is what goes within the <body> tags in a basic HTML5 template. If you need things in the <head> of the document, put that code here.

!
Insecure Resource

The resource you are linking to is using the 'http' protocol, which may not work when the browser is using https.

CSS

About CSS Preprocessors

CSS preprocessors help make authoring CSS easier. All of them offer things like variables and mixins to provide convenient abstractions.

Learn more · Versions

CSS Base

About CSS Base

It's a common practice to apply CSS to a page that styles elements such that they are consistent across all browsers. We offer two of the most popular choices: normalize.css and a reset. Or, choose Neither and nothing will be applied.

Vendor Prefixing

About Vendor Prefixing

To get the best cross-browser support, it is a common practice to apply vendor prefixes to CSS properties and values that require them to work. For instance -webkit- or -moz-.

We offer two popular choices: Autoprefixer (which processes your CSS server-side) and -prefix-free (which applies prefixes via a script, client-side).

Add External Stylesheets/Pens

Any URLs added here will be added as <link>s in order, and before the CSS in the editor. You can use the CSS from another Pen by using its URL and the proper URL extension.

Powered by Algolia
About External Resources

You can apply CSS to your Pen from any stylesheet on the web. Just put a URL to it here and we'll apply it, in the order you have them, before the CSS in the Pen itself.

You can also link to another Pen here (use the .css URL Extension) and we'll pull the CSS from that Pen and include it. If it's using a matching preprocessor, use the appropriate URL Extension and we'll combine the code before preprocessing, so you can use the linked Pen as a true dependency.

Learn more

+ add another resource

JavaScript

About JavaScript Preprocessors

JavaScript preprocessors can help make authoring JavaScript easier and more convenient.

Learn more · Versions

Babel includes JSX processing.

Add External Scripts/Pens

Any URL's added here will be added as <script>s in order, and run before the JavaScript in the editor. You can use the URL of any other Pen and it will include the JavaScript from that Pen.

Powered by Algolia
About External Resources

You can apply a script from anywhere on the web to your Pen. Just put a URL to it here and we'll add it, in the order you have them, before the JavaScript in the Pen itself.

If the script you link to has the file extension of a preprocessor, we'll attempt to process it before applying.

You can also link to another Pen here, and we'll pull the JavaScript from that Pen and include it. If it's using a matching preprocessor, we'll combine the code before preprocessing, so you can use the linked Pen as a true dependency.

Learn more

+ add another resource

Packages

Add Packages

Search for and use JavaScript packages from npm here. By selecting a package, an import statement will be added to the top of the JavaScript editor for this package.

Powered by Algolia
About Packages

Using packages here is powered by esm.sh, which makes packages from npm not only available on a CDN, but prepares them for native JavaScript ESM usage.

All packages are different, so refer to their docs for how they work.

If you're using React / ReactDOM, make sure to turn on Babel for the JSX processing.

Behavior

Auto Save

If active, Pens will autosave every 30 seconds after being saved once.

Auto-Updating Preview

If enabled, the preview panel updates automatically as you code. If disabled, use the "Run" button to update.

Format on Save

If enabled, your code will be formatted when you actively save your Pen. Note: your code becomes un-folded during formatting.

Editor Settings

Code Indentation

Want to change your Syntax Highlighting theme, Fonts and more?

Visit your global Editor Settings.

HTML 

              
                <input type="range" value="50" min="0" max="100" style="--size:50" oninput="this.style='--size:'+this.value" role="img" aria-label="An interactive cartoon of a landscape painting with a tree. It slides and shows the contrast between summer and winter." />
!

CSS 

              
                input {
  --trunk: maroon;
  --ground: white;
  --sky: #dde;
  --sky2: #bbd;
  position: absolute;
  top: 45%;
  left: 50%;
  transform: translate(-50%, -50%);
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
  width: 70vmin;
  height: 50vmin;
  background:
    /* tree */
    conic-gradient(at 50% -20%, #0000 177deg, var(--trunk) 177.25deg 182.75deg, #0000 183deg) 30vmin 50% / 10vmin 30vmin,
    
    
    conic-gradient(at 110% 30%, #0000 237deg, var(--trunk) 237.25deg 245.75deg, #0000 247deg) 35vmin 60% / 10vmin 20vmin,
    conic-gradient(at 110% 40%, #0000 217deg, var(--trunk) 217.25deg 225.75deg, #0000 227deg) 38vmin 48% / 4vmin 10vmin,
    conic-gradient(at 110% 30%, #0000 287deg, var(--trunk) 287.25deg 295.75deg, #0000 297deg) 43vmin 60% / 3vmin 10vmin,
    
    conic-gradient(at 120% 30%, #0000 217deg, var(--trunk) 217.25deg 222.75deg, #0000 223deg) 35vmin 24% / 6vmin 14vmin,
    conic-gradient(at 110% 30%, #0000 277deg, var(--trunk) 277.25deg 282.75deg, #0000 283deg) 39.75vmin 34% / 4vmin 10vmin,
    conic-gradient(at 110% 40%, #0000 237deg, var(--trunk) 227.25deg 235.75deg, #0000 247deg) 41.75vmin 28% / 2vmin 8vmin,
    
    conic-gradient(at 120% 30%, #0000 207deg, var(--trunk) 207.25deg 212.75deg, #0000 213deg) 35vmin 10% / 3vmin 9vmin,
    conic-gradient(at 120% 30%, #0000 217deg, var(--trunk) 217.25deg 223.75deg, #0000 224deg) 35vmin 21% / 3vmin 9vmin,
    
    conic-gradient(at -40% 30%, #0000 95deg, var(--trunk) 0 100deg, #0000 0) 26vmin 50% / 9vmin 10vmin,
    conic-gradient(at -40% 10%, #0000 115deg, var(--trunk) 0 120deg, #0000 0) 28vmin 47% / 4vmin 6vmin,
    conic-gradient(at -40% 80%, #0000 36deg, var(--trunk) 0 40deg, #0000 0) 31vmin 60% / 9vmin 10vmin,
    
     conic-gradient(at -40% -20%, #0000 110deg, var(--trunk) 0 115deg, #0000 0) 27.5vmin 38% / 7.5vmin 6vmin,
    conic-gradient(at 0% -20%, #0000 160deg, var(--trunk) 0 165deg, #0000 0) 29vmin 30% / 7.5vmin 4vmin,
    
    conic-gradient(at 0% -20%, #0000 150deg, var(--trunk) 0 158deg, #0000 0) 31.5vmin 25% / 4vmin 6vmin,
    
    /* snow */
    radial-gradient(closest-side, white 40%, #0000 0) 70% 70% / 1vmin 1vmin,
    radial-gradient(closest-side, white 50%, #0000 0) 60% 60% / 1vmin 1vmin,
    radial-gradient(closest-side, white 60%, #0000 0) 80% 30% / 1vmin 1vmin,
    radial-gradient(closest-side, white 70%, #0000 0) 90% 60% / 1vmin 1vmin,
    radial-gradient(closest-side, white 40%, #0000 0) 50% 10% / 1vmin 1vmin,
    radial-gradient(closest-side, white 50%, #0000 0) 55% 25% / 1vmin 1vmin,
    radial-gradient(closest-side, white 60%, #0000 0) 65% 15% / 1vmin 1vmin,
    radial-gradient(closest-side, white 70%, #0000 0) 75% 34% / 1vmin 1vmin,
    radial-gradient(closest-side, white 40%, #0000 0) 85% 10% / 1vmin 1vmin,
    radial-gradient(closest-side, white 50%, #0000 0) 95% 77% / 1vmin 1vmin,
    radial-gradient(closest-side, white 60%, #0000 0) 72% 50% / 1vmin 1vmin,
    radial-gradient(closest-side, white 70%, #0000 0) 92% 35% / 1vmin 1vmin,
    
    radial-gradient(closest-side, white 40%, #0000 0) 5% 70% / 1vmin 1vmin,
    radial-gradient(closest-side, white 50%, #0000 0) 15% 60% / 1vmin 1vmin,
    radial-gradient(closest-side, white 60%, #0000 0) 25% 30% / 1vmin 1vmin,
    radial-gradient(closest-side, white 70%, #0000 0) 35% 60% / 1vmin 1vmin,
    radial-gradient(closest-side, white 40%, #0000 0) 45% 10% / 1vmin 1vmin,
    radial-gradient(closest-side, white 50%, #0000 0) 17% 25% / 1vmin 1vmin,
    radial-gradient(closest-side, white 60%, #0000 0) 37% 15% / 1vmin 1vmin,
    radial-gradient(closest-side, white 70%, #0000 0) 27% 34% / 1vmin 1vmin,
    radial-gradient(closest-side, white 40%, #0000 0) 46% 70% / 1vmin 1vmin,
    radial-gradient(closest-side, white 50%, #0000 0) 22% 77% / 1vmin 1vmin,
    radial-gradient(closest-side, white 60%, #0000 0) 28% 50% / 1vmin 1vmin,
    radial-gradient(closest-side, white 70%, #0000 0) 10% 10% / 1vmin 1vmin,
    /* background */
    radial-gradient(175vmin 50% at 35vmin 95%, var(--ground) 30%, #0000 30.25%),
    radial-gradient(farthest-side at 50% 70%, #bb6, #aa5 99%, #0000) 6.5vmin 84% / 11vmin 7vmin,
    radial-gradient(farthest-side at 50% 70%, #fff 99%, #0000 0) 7vmin 84% / 10vmin 8vmin,
    radial-gradient(farthest-side at 50% 110%, #def 99%, #0000 0) 38vmin 87% / 100vmin 10vmin,
    linear-gradient(var(--sky2), var(--sky))
    ;
  background-repeat: no-repeat;
  background-color: #f002;
  overflow: hidden;
  border: 5vmin ridge #963;
  box-shadow: 
    -21vmin 38vmin 0 -29.25vmin #fff,
    -26.75vmin 38vmin 0 -29.5vmin #222,
    -27vmin 40vmin 0 -29.75vmin #888,
    -26vmin 40vmin 0 -29.75vmin #fff,
    -22vmin 40vmin 0 -29.75vmin #888,
    -21.5vmin 41.5vmin 0 -29.75vmin #888,
    -22.5vmin 41.5vmin 0 -29.75vmin #fff,
    -27vmin 41.5vmin 0 -29.75vmin #888,
    -21vmin 43vmin 0 -29.75vmin #fff,
    -27vmin 43vmin 0 -29.75vmin #888,
    -25vmin 40vmin 0 -25vmin white,
    -24.75vmin 40.25vmin 0 -25vmin #0002,
    0 0 0 100vmax #def;
}

input::before {
  --trunk: brown;
  --ground: green;
  --sky2: #aef;
  --sky: #8ce;
  content: "";
  display: block;
  position: absolute;
  top: 0;
  left: 0;
  width: calc(var(--size) * 1%);
  height: 100%;
  background:
    /* leaves */
    radial-gradient(closest-side, #00c300 90%, #0000 0) 23vmin 27% / 9vmin 9vmin,
    radial-gradient(closest-side, #0b0 99%, #0000 0) 35vmin 30% / 10vmin 9vmin,
    radial-gradient(closest-side, #0b0 99%, #0000 0) 31vmin 42% / 10vmin 9vmin,
    radial-gradient(closest-side, #0b0 99%, #0000 0) 35vmin 49% / 7vmin 6vmin,
    radial-gradient(closest-side, #0b0 90%, #0000 0) 27vmin 23% / 12vmin 9vmin,
    radial-gradient(closest-side, #0b0 99%, #0000 0) 26vmin 47% / 9vmin 6vmin,
    radial-gradient(closest-side, #0b0 80%, #0000 0) 39vmin 50% / 9vmin 9vmin,
    radial-gradient(closest-side, #0b0 70%, #0000 0) 28vmin 57% / 9vmin 9vmin,
    radial-gradient(closest-side, #0b0 84%, #0000 0) 30.5vmin 10% / 9vmin 9vmin,
    /* tree */
    conic-gradient(at 50% -20%, #0000 177deg, var(--trunk) 177.25deg 182.75deg, #0000 183deg) 30vmin 50% / 10vmin 30vmin,
    
    conic-gradient(at 110% 30%, #0000 237deg, var(--trunk) 237.25deg 245.75deg, #0000 247deg) 35vmin 60% / 10vmin 20vmin,
    conic-gradient(at 110% 40%, #0000 217deg, var(--trunk) 217.25deg 225.75deg, #0000 227deg) 37.75vmin 48% / 4vmin 10vmin,
    conic-gradient(at 110% 30%, #0000 287deg, var(--trunk) 287.25deg 295.75deg, #0000 297deg) 42.75vmin 60% / 3vmin 10vmin,
    
    conic-gradient(at 120% 30%, #0000 217deg, var(--trunk) 217.25deg 222.75deg, #0000 223deg) 35vmin 24% / 6vmin 14vmin,
    conic-gradient(at 110% 30%, #0000 277deg, var(--trunk) 277.25deg 282.75deg, #0000 283deg) 40vmin 34% / 4vmin 10vmin,
    conic-gradient(at 110% 40%, #0000 237deg, var(--trunk) 227.25deg 235.75deg, #0000 247deg) 42vmin 28% / 2vmin 8vmin,
    
    conic-gradient(at 120% 30%, #0000 207deg, var(--trunk) 207.25deg 212.75deg, #0000 213deg) 35vmin 10% / 3vmin 9vmin,
    conic-gradient(at 120% 30%, #0000 217deg, var(--trunk) 217.25deg 223.75deg, #0000 224deg) 35vmin 21% / 3vmin 9vmin,
    
    conic-gradient(at -40% 30%, #0000 95deg, var(--trunk) 0 100deg, #0000 0) 26vmin 50% / 9vmin 10vmin,
    conic-gradient(at -40% 10%, #0000 115deg, var(--trunk) 0 120deg, #0000 0) 28vmin 47% / 4vmin 6vmin,
    conic-gradient(at -40% 80%, #0000 36deg, var(--trunk) 0 40deg, #0000 0) 31vmin 60% / 9vmin 10vmin,
    
     conic-gradient(at -40% -20%, #0000 110deg, var(--trunk) 0 115deg, #0000 0) 27.5vmin 38% / 7.5vmin 6vmin,
    conic-gradient(at 0% -20%, #0000 160deg, var(--trunk) 0 165deg, #0000 0) 29vmin 30% / 7.5vmin 4vmin,
    
    conic-gradient(at 0% -20%, #0000 150deg, var(--trunk) 0 158deg, #0000 0) 31.5vmin 25% / 4vmin 6vmin,
    /* leaves */
    radial-gradient(closest-side, #090 90%, #0000 0) 25vmin 22% / 12vmin 12vmin,
    
    radial-gradient(closest-side, #080 99%, #0000 0) 35vmin 25% / 9vmin 9vmin,
    radial-gradient(closest-side, #070 80%, #0000 0) 39vmin 50% / 9vmin 9vmin,
    radial-gradient(closest-side, #090 80%, #0000 0) 23vmin 47% / 10vmin 10vmin,
    radial-gradient(closest-side, #080 84%, #0000 0) 27.5vmin 57% / 9vmin 9vmin,
    radial-gradient(closest-side, #080 84%, #0000 0) 30.5vmin 60% / 9vmin 9vmin,
    radial-gradient(closest-side, #080 84%, #0000 0) 25.5vmin 35% / 9vmin 9vmin,
    radial-gradient(closest-side, #070 90%, #0000 0) 30vmin 42% / 16vmin 16vmin,
    /* sun */
    radial-gradient(circle at 14vmin 20%, #ff8e 4vmin, #fff0 12vmin),
    /* background */
    radial-gradient(175vmin 50% at 35vmin 95%, var(--ground) 30%, #0000 0),
    radial-gradient(farthest-side at 50% 70%, #0b0 99%, #0000) 6.5vmin 84% / 11vmin 7vmin,
    
    radial-gradient(farthest-side at 50% 110%, #0a0 99%, #0000 0) 38vmin 87% / 100vmin 10vmin,
    linear-gradient(var(--sky2), var(--sky))
    ;
  box-shadow:
    inset -2px 0, 0 0 0 2px;
  background-repeat: no-repeat;
  background-color: #f002;
}


input::after {
  content: "";
  display: block;
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  box-shadow: 
    inset 0 0 0 2vmin #ffd,
    inset 0 0 1vmin 1.5vmin;
}

/* hide the range handler */
input[type=range]::-webkit-slider-thumb {
  -webkit-appearance: none;
  background: transparent;
  border: 0 solid transparent;
  width: 10%;
  height: 10%;
  display: block;
}

input[type=range]::-moz-range-thumb {
  -webkit-appearance: none;
  background: transparent;
  border: 0 solid transparent;
  width: 10%;
  height: 10%;
  display: block;
}

input[type=range]::-ms-track {
  width: 100%;
  cursor: pointer;
  background: transparent; 
  border-color: transparent;
  color: transparent;
}
!

JS
!
999px

Console