JSFiddle - React, Tailwind, and code Playground

HTML

<div>Testing greying out background. </div>

<div class="loading" align="center">
        <div class="main">
            <div class="small1">
              <div class="small ball smallball1"></div>
              <div class="small ball smallball2"></div>
              <div class="small ball smallball3"></div>
              <div class="small ball smallball4"></div>
            </div>

            <div class="small2">
              <div class="small ball smallball5"></div>
              <div class="small ball smallball6"></div>
              <div class="small ball smallball7"></div>
              <div class="small ball smallball8"></div>
            </div>

            <div class="bigcon">
              <div class="big ball"></div>
            </div>
        </div>
    </div>

CSS

body {
  padding: 0px;
  height:100%;
    background-color:#EBEBEB;
    filter:alpha(opacity=70);
    opacity:0.7;
  background-color: #EBEBEB;
}

.main {
    background-color:#EBEBEB;
    filter:alpha(opacity=70);
    opacity:0.7;
}

.main:before{
    position: absolute;
    content:"";
    width: 100%;
    background: rgba(193, 56, 50, 0.7); // Adjust your color
    height: 100%;
    left:0;
    z-index:-1;
}

.small2 {
  position: absolute;
  height: 100px;
  width: 100px;
  background-color: transparent;
  top: 50vh;
  left: 50%;
  transform: translate(-50%, -50%);
}

.small1 {
  position: absolute;
  height: 100px;
  width: 100px;
  top: 50vh;
  left: 50%;
  transform-origin: center;
  transform: translate(-50%, -50%) rotate(45deg);
  background-color: transparent;
}

.bigcon {
  position: absolute;
  height: 95px;
  width: 95px;
  top: 50vh;
  left: 50%;
  transform-origin: center;
  transform: translate(-50%, -50%) rotate(-45deg);
  background-color: transparent;
  animation: bigcon 2s infinite linear;
  animation-delay: 0.25s;
}

.ball {
  border-radius: 50%;
  position: absolute;
}

.small {
  width: 25px;
  height: 25px;
  animation: small 2s infinite ease;
  box-shadow: 0px 2px rgba(0,0,0,0.3);
  background-color: #46b9ff;
}

.small:nth-child(1) {
  top: 0%;
  left: 0%;
}

.small:nth-child(2) {
  top: 0%;
  right: 0%;
}

.small:nth-child(3) {
  right: 0%;
  bottom: 0%;
}

.small:nth-child(4) {
  bottom: 0%;
  left: 0%;
}

.big {
  width: 20px;
  height: 20px;
  border-radius: 15px;
  box-shadow:0px 0px 10px #54f7f8, 0px 0px 20px #54f7f8, 0px 0px 30px #54f7f8, 0px 0px 50px #54f7f8, 0px 0px 60px #54f7f8 ;
  z-index: 1;
  background-color: #54f7f8;
  animation: bigball 1s infinite linear;
}

.smallball1{
  animation-delay: -1.75s;
}
.smallball6{
  animation-delay: -1.5s;
}
.smallball2{
  animation-delay: -1.25s;
}
.smallball7{
  animation-delay: -1s;
}
.smallball3{
  animation-delay: -0.75s;
}
.smallball8{
  animation-delay: -0.5s;
}
.smallball4{
 ...

JavaScript

function ShowProgress() {
            setTimeout(function () {
                var loading = $(".loading");
                loading.show();
                $('#overlay').css({ 'display': 'block', opacity: 0.7, 'width': $(document).width(), 'height': $(document).height() });
                $('body').css({'overflow':'hidden'});
                $('#loading').css({ 'display': 'block' }).click(function () { $(this).css('display', 'none'); $('#screen').css('display', 'none') });            
            }, 5);
            $('#main').dialog({ modal: true });
        }


        $('form').live("submit", function () {       
            $(".overlay").show();
            ShowProgress();
        });