body {
  font-family: 'Montserrat', sans-serif;
  background: #1e293b;
  color: #f8fafc;
}

.app {
  min-width: 100vw;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
}

header { 
  display: flex;
  flex-direction: column;
  align-items: center;
  margin: 1rem;
  text-align: center;
  
  h1 {
    font-weight: 600;
    font-size: 2rem;
    margin-bottom: 0.5rem;
    
    @media (min-width: 768px) {
      font-size: 3rem;
    }
  }
  
  p {
    color: #94a3b8;
  }
}

.tag-list {
  width: 30rem;
  max-width: 90vw;
  display: flex;
  flex-shrink: 0;
  flex-direction: column;
  gap: 1rem 0;
  position: relative;
  padding: 1.5rem 0;
  overflow: hidden;
}

.loop-slider {
  .inner {
    display: flex;
    width: fit-content;
    animation-name: loop;
    animation-timing-function: linear;
    animation-iteration-count: infinite;
    animation-direction: var(--direction);
    animation-duration: var(--duration);
  }
}

.tag {
  display: flex;
  align-items: center;
  gap: 0 0.2rem;
  color: #e2e8f0;
  font-size: 0.9rem;
  background-color: #334155;
  border-radius: 0.4rem;
  padding: 0.7rem 1rem;
  margin-right: 1rem; // Must used margin-right instead of gap for the loop to be smooth
  box-shadow: 
    0 0.1rem 0.2rem rgb(0 0 0 / 20%),
    0 0.1rem 0.5rem rgb(0 0 0 / 30%),
    0 0.2rem 1.5rem rgb(0 0 0 / 40%);
  
  span {
    font-size: 1.2rem;
    color: #64748b;
  }
}

.fade {
  pointer-events: none;
  background: linear-gradient(90deg, #1e293b, transparent 30%, transparent 70%, #1e293b);
  position: absolute;
  inset: 0;
}

@keyframes loop {
  0% {
    transform: translateX(0);
  }
  100% {
    transform: translateX(-50%);
  }
}
View Compiled
import React from 'https://cdn.skypack.dev/react';
import ReactDOM from 'https://cdn.skypack.dev/react-dom';

const COLORS = ['#bbf7d0', '#99f6e4', '#bfdbfe', '#ddd6fe', '#f5d0fe', '#fed7aa', '#fee2e2'];
const TAGS = ['HTML', 'CSS', 'JavaScript', 'Typescript', 'Tailwind', 'React', 'Next.js', 'Gatsby', 'UI/UX', 'SVG', 'animation', 'webdev'];
const DURATION = 15000;
const ROWS = 5;
const TAGS_PER_ROW = 5;

const random = (min, max) => Math.floor(Math.random() * (max - min)) + min;
const shuffle = (arr) => [...arr].sort( () => .5 - Math.random() );

const InfiniteLoopSlider = ({children, duration, reverse = false}) => {
  return (
    <div className='loop-slider' style={{
        '--duration': `${duration}ms`,
        '--direction': reverse ? 'reverse' : 'normal'
      }}>
      <div className='inner'>
        {children}
        {children}
      </div>
    </div>
  );
};

const Tag = ({ text }) => (
  <div className='tag'><span>#</span> {text}</div>
);

const App = () => (
  <div className='app'>
    <header>
      <h1>Infinite Scroll Animation</h1>
      <p>CSS only, content independent, bi-directional, customizable</p>
    </header>
    <div className='tag-list'>
      {[...new Array(ROWS)].map((_, i) => (
        <InfiniteLoopSlider key={i} duration={random(DURATION - 5000, DURATION + 5000)} reverse={i % 2}>
          {shuffle(TAGS).slice(0, TAGS_PER_ROW).map(tag => (
            <Tag text={tag} key={tag}/>
          ))}
        </InfiniteLoopSlider>
      ))}
      <div className='fade'/>
    </div>
  </div>
);

ReactDOM.render(
  <App/>,
  document.body
);
View Compiled
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