Слайдер с размытыми градиентными не активными слайдами

Для эффекта размытия в местах сопряжения слайдов используется SVG c фильтром размытия

HTML

<a href="https://youtu.be/zf7nnM0XjkU" target="_blank" data-keyframers-credit style="color: #FFF"></a>
<script src="https://codepen.io/shshaw/pen/QmZYMG.js"></script>

<svg class="goo-filter" viewBox="0 0 1 1">
  <filter id="goo">
    <feGaussianBlur in="SourceGraphic" stdDeviation="10" result="blur" />
    <feColorMatrix in="blur" mode="matrix" values="1 0 0 0 0  0 1 0 0 0  0 0 1 0 0  0 0 0 50 -20" result="goo" />
<!--     <feBlend in="SourceGraphic" in2="goo" /> -->
  </filter>
</svg>

<main id="app">
  
  <section class="backgrounds">
    <div 
         class="background" 
         style="--primary: var(--pink); --secondary: var(--orange)">
    </div>
    <div 
         class="background" 
         data-active="true" style="--primary: var(--purple); --secondary: var(--pink)">
    </div>
    <div 
         class="background" 
         style="--primary: var(--green); --secondary: var(--cyan)">
    </div>
    <div 
         class="background" 
         style="--primary: var(--blue); --secondary: var(--purple)">
    </div>
  </section>
  
  <section class="content">
    <article>
      <header>
        <h1>Get the middle seat if you don't check in on time</h1>
      </header>
      <p>Lorem ipsum dolor sit amet consectetur adipisicing elit.</p>
    </article>
    <article data-active="true" >
      <header>
        <h1>Your boarding zone is "recruiter"</h1>
      </header>
      <p>Lorem ipsum dolor sit amet consectetur adipisicing elit. Voluptate, reiciendis.</p>
    </article>
    <article data-id="3" >
      <header>
        <h1>Check in for your flight online</h1>
      </header>
      <p>Lorem ipsum dolor sit amet consectetur adipisicing elit. Amet dignissimos corporis dolor.</p>
    </article>
    <article data-id="4">
      <header>
        <h1>Get through security eventually</h1>
      </header>
      <p>Lorem ipsum dolor sit amet consectetur, adipisicing elit. Sint eaque adipisci sit?</p>
    </article>
  </section>
</main>

SCSS

:root {
  --green: #37c4b1;
  --cyan: #25aad8;
  --blue: #4092e3;
  --purple: #7d54c1;
  --pink: #c776a3;
  --orange: #ee8877;
  --deep-purple: #281c4c;

  --duration: 0.7s;
  --ease: cubic-bezier(0.6, 0, 0.2, 1);
  --transition: transform var(--duration) var(--ease);
}

*,
*:before,
*:after {
  box-sizing: border-box;
  position: relative;
}

html,
body {
  height: 100%;
  width: 100%;
  margin: 0;
  padding: 0;
}

body {
  display: flex;
  justify-content: center;
  align-items: center;
  background-color: var(--deep-purple);
  overflow: hidden;
}

.goo-filter { position: absolute; visibility: hidden; }

#app {
  display: grid;
  grid-template-columns: 1fr;
  grid-template-rows: 1fr;
  height: 90vmin;
  width: 55vmin;

  > section {
    margin: 5vmin 8vmin;
    grid-area: 1 / 1; 
  }
}

section {
  display: grid;
  grid-template-columns: 1fr;
  grid-template-rows: 1fr;
  transform-style: preserve-3d;
  perspective: 800px;
  will-change: transform;

  > * {
    flex: 0 0 100%;
    grid-area: 1 / 1;
  }

}

.backgrounds {
  filter: url("#goo");
  pointer-events: none;
}

.background {
  will-change: transform;
  border-radius: 2vmin;
  background-image: linear-gradient(
    to bottom,
    var(--primary, blue),
    var(--secondary, pink)
  );

  &::before {
    content: "";
    position: absolute;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    margin: auto;
    z-index: 3;
    background-image: linear-gradient(to bottom, #4b3777, #331847);
    
    opacity: 0.8;
    transition: inherit;
    transition-property: opacity;
  }
  
  &[data-active] {
    &::before {
      opacity: 0.01;
    }
  }
}

article {
  display: flex;
  flex-direction: column;
}

.background,
article {
  will-change: transform;

  transition: var(--transition);
  transition-property: transform, transform-origin, z-index;
  padding: 5vmin;
  color: white;

  transform-origin: right center;
  transform: translateX(-90%) translateZ(-25vmin) rotateY(40deg);

  &[data-active] {
    transform-origin: center center;
    transform: translateX(0) translateZ(0) rotateY(0deg);
    z-index: 3;
  }

  &[data-active] ~ * {
    z-index: -1;
    transform-origin: left center;
    transform: translateX(140%) translateZ(-25vmin) rotateY(-40deg);
  }

  &[data-active] + * {
    z-index: 1;
    transform: translateX(90%) translateZ(-25vmin) rotateY(-40deg);
  }
}

article {
  opacity: 0;
  transition-property: transform, transform-origin, opacity, z-index;
  
  &[data-active] {
    opacity: 1;
  }
}

h1 {
  font-size: 4vmin;
  line-height: 1.2;
}

p {
  font-size: 2.5vmin;
  line-height: 1.4;
  color: rgba(white, 0.6);
}

JS

console.clear();

const elApp = document.querySelector("#app");
const elBackgrounds = Array.from(document.querySelectorAll(".background"));
const elArticles = Array.from(document.querySelectorAll(".content article"));

elArticles.forEach(article => {
  article.addEventListener("click", e => {
    const index = elArticles.indexOf(article);
    const bg = elBackgrounds[index];
    
    // Remove all data-active
    elApp.querySelectorAll("[data-active]").forEach(el => {
      el.removeAttribute("data-active");
    });
    
    article.setAttribute("data-active", true);
    bg.setAttribute('data-active', true);
  });
});