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HTML

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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.

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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>

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!
Insecure Resource

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CSS

About CSS Preprocessors

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

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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-.

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JavaScript

About JavaScript Preprocessors

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

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Babel includes JSX processing.

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HTML 

              
                <div id='holder' style='background-color:#000; width:800px; height:300px; position:relative'>

  <div id='effect' style='position:absolute; width:800px; height:300px'></div>

</div>
!

CSS 

              
                html, body, div, span, applet, object, iframe,
h1, h2, h3, h4, h5, h6, p, blockquote, pre,
a, abbr, acronym, address, big, cite, code,
del, dfn, em, font, img, ins, kbd, q, s, samp,
small, strike, strong, sub, sup, tt, var,
b, u, i, center,
dl, dt, dd, ol, ul, li,
fieldset, form, label, legend,
table, caption, tbody, tfoot, thead, tr, th, td {
  margin: 0;
  padding: 0;
  border: 0;
  outline: 0;
  font-size: 100%;
  vertical-align: baseline;
  background: transparent;
  box-sizing: border-box;
}

body {
  overflow: hidden;
  background-color: #111;
}
!

JS 

              
                $( document ).ready( function() {

  var mobile = false;

  //---

  if ( isMobile.phone || isMobile.tablet ) {
      
    mobile = true;
      
  }
  
  //---

  var canvasWidth = 800;
  var canvasHeight = 300;

  //---

  var canvas = document.createElement( 'canvas' );
  canvas.setAttribute( 'width', canvasWidth );
  canvas.setAttribute( 'height', canvasHeight );
  canvas.oncontextmenu = function( e ) {
    e.preventDefault();
  };

  if ( !mobile ) {    

    canvas.addEventListener( 'mousemove', mouseMoveHandler );
    canvas.addEventListener( 'mousedown', mouseDownHandler );
    canvas.addEventListener( 'mouseup', mouseUpHandler );
    canvas.addEventListener( 'mouseenter', mouseEnterHandler ); 
    canvas.addEventListener( 'mouseleave', mouseLeaveHandler ); 

    $( canvas ).css( 'cursor', 'pointer' );

  } else {

    canvas.addEventListener( 'touchstart', touchStartHandler, false );
    canvas.addEventListener( 'touchend', touchEndHandler, false );
    canvas.addEventListener( 'touchmove', touchMoveHandler, false );
    canvas.addEventListener( 'touchcancel', touchCancelHandler, false );

  }

  document.getElementById( 'effect' ).appendChild( canvas );

  //---

  var ctx = canvas.getContext( '2d' );
  var imageData = ctx.getImageData( 0, 0, canvasWidth, canvasHeight );
  var pix = imageData.data;

  //---

  var MATHPI180 = Math.PI / 180;
  var MATHPI2 = Math.PI * 2;

  var center = { x:canvas.width / 2, y:canvas.height / 2 };

  //---

  var mouseActive = false;
  var mouseDown = false;
  var mousePos = { x:center.x, y:center.y };

  //---

  var rotationSpeed = -1.00;
  var rotationSpeedFactor = { x: 0, y: 0 };
  rotationSpeedFactor.x = rotationSpeed / center.x;
  rotationSpeedFactor.y = rotationSpeed / center.y;

  var fov = 300;
  var fovMin = 210;
  var fovMax = fov;

  var starHolderCount = 6666;
  var starHolder = [];
  var starBgHolder = [];
  var starSpeed = 20;
  var starSpeedMin = starSpeed;
  var starSpeedMax = 200;
  var starDistance = 8000;
  var starRotation = 0;

  var backgroundColor = { r:0, g:0, b:0, a:0 };

  var colorInvertValue = 0;

  //---

  function clearImageData() {

    for ( var i = 0, l = pix.length; i < l; i += 4 ) {

      pix[ i ] = backgroundColor.r;
      pix[ i + 1 ] = backgroundColor.g;
      pix[ i + 2 ] = backgroundColor.b;
      pix[ i + 3 ] = backgroundColor.a;

    }

  };

  function setPixel( x, y, r, g, b, a ) {

    var i = ( x + y * canvasWidth ) * 4;

    pix[ i ] = r;
    pix[ i + 1 ] = g;
    pix[ i + 2 ] = b;
    pix[ i + 3 ] = a;

  };

  function setPixelAdditive( x, y, r, g, b, a ) {

    var i = ( x + y * canvasWidth ) * 4;

    pix[ i ]     = pix[ i ] + r;
    pix[ i + 1 ] = pix[ i + 1 ] + g;
    pix[ i + 2 ] = pix[ i + 2 ] + b;
    pix[ i + 3 ] = a;

  };

  //---
  
  function drawLine( x1, y1, x2, y2, r, g, b, a ) {

    var dx = Math.abs( x2 - x1 );
    var dy = Math.abs( y2 - y1 );

    var sx = ( x1 < x2 ) ? 1 : -1;
    var sy = ( y1 < y2 ) ? 1 : -1;

    var err = dx - dy;

    var lx = x1;
    var ly = y1;    

    while ( true ) {

      if ( lx > 0 && lx < canvasWidth && ly > 0 && ly < canvasHeight ) {

        setPixel( lx, ly, r, g, b, a );

      }

      if ( ( lx === x2 ) && ( ly === y2 ) )
        break;

      var e2 = 2 * err;

      if ( e2 > -dx ) { 

        err -= dy; 
        lx += sx; 

      }

      if ( e2 < dy ) { 

        err += dx; 
        ly += sy; 

      }

    }

  };

  //---

  function addParticle( x, y, z, ox, oy, oz ) {

    var particle = {};
    particle.x = x;
    particle.y = y;
    particle.z = z;
    particle.ox = ox;
    particle.oy = oy;
    particle.x2d = 0;
    particle.y2d = 0;

    return particle;

  };

  function addParticles() {

    var i;

    var x, y, z;

    var colorValue;
    var particle;

    for ( i = 0; i < starHolderCount / 3; i++ ) {

      x = Math.random() * 24000 - 12000;
      y = Math.random() * 4500 - 2250;
      z = Math.round( Math.random() * starDistance );//Math.random() * 700 - 350;

      colorValue = Math.floor( Math.random() * 55 ) + 5;

      particle = addParticle( x, y, z, x, y, z );
      particle.color = { r:colorValue, g:colorValue, b:colorValue, a:255 };

      starBgHolder.push( particle );

    }

    for ( i = 0; i < starHolderCount; i++ ) {

      x = Math.random() * 10000 - 5000;
      y = Math.random() * 10000 - 5000;
      z = Math.round( Math.random() * starDistance );//Math.random() * 700 - 350;

      colorValue = Math.floor( Math.random() * 155 ) + 100;

      particle = addParticle( x, y, z, x, y, z );
      particle.color = { r:colorValue, g:colorValue, b:colorValue, a:255 };
      particle.oColor = { r:colorValue, g:colorValue, b:colorValue, a:255 };
      particle.w = 1;
      particle.distance = starDistance - z;
      particle.distanceTotal = Math.round( starDistance + fov - particle.w );

      starHolder.push( particle );

    }

  };

  //---

  window.requestAnimFrame = ( function() {

    return  window.requestAnimationFrame       ||
      window.webkitRequestAnimationFrame ||
      window.mozRequestAnimationFrame    ||
      function( callback ) {
      window.setTimeout( callback, 1000 / 60 );
    };

  } )();

  function animloop() {

    requestAnimFrame( animloop );
    render();

  };

  function render() {

    clearImageData();

    //---

    var i, j, l, k, m, n;

    //---

    var rx, rz;

    var star;
    var scale;

    //---

    if ( mouseActive ) {

      starSpeed += 2;

      if ( starSpeed > starSpeedMax )
        starSpeed = starSpeedMax;

    } else {

      starSpeed -= 1;

      if ( starSpeed < starSpeedMin )
        starSpeed = starSpeedMin;

    }

    //---

    if ( !mouseActive ) {

      fov += 0.5;

      if ( fov > fovMax )
        fov = fovMax;

    } else {

      fov -= 1;

      if ( fov < fovMin )
        fov = fovMin;

    }

    //---

    var warpSpeedValue;

    if ( mobile ) {

      warpSpeedValue = starSpeed * ( starSpeed / starSpeedMax );

    } else {

      warpSpeedValue = starSpeed * ( starSpeed / ( starSpeedMax / 2 ) );

    }

    //---

    for ( i = 0, l = starBgHolder.length; i < l; i++ ) {

      star = starBgHolder[ i ];

      scale = fov / ( fov + star.z ); 

      star.x2d = ( star.x * scale ) + center.x; 
      star.y2d = ( star.y * scale ) + center.y; 

      if ( star.x2d > 0 && star.x2d < canvasWidth && star.y2d > 0 && star.y2d < canvasHeight ) {

        setPixel( star.x2d | 0, star.y2d | 0, star.color.r, star.color.g, star.color.b, 255 );

      }


    }

    //---

    for ( i = 0, l = starHolder.length; i < l; i++ ) {

      star = starHolder[ i ];

      star.z -= starSpeed;
      star.distance += starSpeed;

      if ( star.z < -fov + star.w ) {

        star.z = starDistance;
        star.distance = 0;

      } 

      //---
      //star color

      var distancePercent = star.distance / star.distanceTotal;

      star.color.r = Math.floor( star.oColor.r * distancePercent );
      star.color.g = Math.floor( star.oColor.g * distancePercent );
      star.color.b = Math.floor( star.oColor.b * distancePercent );

      //---
      //star draw

      scale = fov / ( fov + star.z ); 

      star.x2d = ( star.x * scale ) + center.x; 
      star.y2d = ( star.y * scale ) + center.y; 

      if ( star.x2d > 0 && star.x2d < canvasWidth && star.y2d > 0 && star.y2d < canvasHeight ) {

        setPixelAdditive( star.x2d | 0, star.y2d | 0, star.color.r, star.color.g, star.color.b, 255 );

      }

      if ( starSpeed != starSpeedMin ) {

        var nz = star.z + warpSpeedValue;

        scale = fov / ( fov + nz ); 

        var x2d = ( star.x * scale ) + center.x; 
        var y2d = ( star.y * scale ) + center.y; 

        if ( x2d > 0 && x2d < canvasWidth && y2d > 0 && y2d < canvasHeight ) {

          drawLine( star.x2d | 0, star.y2d | 0, x2d | 0, y2d | 0, star.color.r, star.color.g, star.color.b, 255 );

        }

      }

      if ( mouseDown ) {

        //rotation
        var radians = MATHPI180 * starRotation;

        var cos = Math.cos( radians );
        var sin = Math.sin( radians );

        star.x = ( cos * ( star.ox - center.x ) ) + ( sin * ( star.oy - center.y ) ) + center.x,
          star.y = ( cos * ( star.oy - center.y ) ) - ( sin * ( star.ox - center.x ) ) + center.y;

      }

    }

    //---

    ctx.putImageData( imageData, 0, 0 );

    //---

    if ( mouseActive ) {

      center.x += ( mousePos.x - center.x ) * 0.015;

    } else {

      center.x += ( ( canvas.width / 2 ) - center.x ) * 0.015;

    }

    //---
    
    if ( mouseDown ) {

      starRotation -= 0.5;

    }

  };

  //---

  function mouseMoveHandler( event ) {

    mousePos = getMousePos( canvas, event );

  };

  function mouseEnterHandler( event ) {

    mouseActive = true;

  };

  function mouseLeaveHandler( event ) {

    mouseActive = false;

    mouseDown = false;

  };

  function mouseDownHandler( event ) {

    mouseDown = true;

    speed = 0;

  };

  function mouseUpHandler( event ) {

    mouseDown = false;

    speed = 0.25;

  };

  //---

  function getMousePos( canvas, event ) {

    var rect = canvas.getBoundingClientRect();

    return { x: event.clientX - rect.left, y: event.clientY - rect.top };

  };

  //---

  function touchStartHandler( event ) {

    event.preventDefault();

    mouseDown = true;
    mouseActive = true;

  };

  function touchEndHandler( event ) {

    event.preventDefault();

    mouseDown = false;
    mouseActive = false;

  };

  function touchMoveHandler( event ) {

    event.preventDefault();

    mousePos = getTouchPos( canvas, event );

  };

  function touchCancelHandler( event ) {

    mouseDown = false;
    mouseActive = false;

  };

  //---

  function getTouchPos( canvas, event ) {

    var rect = canvas.getBoundingClientRect();

    return { x: event.touches[ 0 ].clientX - rect.left, y: event.touches[ 0 ].clientY - rect.top };

  };

  //---

  addParticles();
  animloop();

} );
!
999px

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