CristinaSolana

const options = {
  root: null, // use null for viewport
  rootMargin: '0px',
  threshold: 1.0
};
const observer = new IntersectionObserver(callback, options);
const target = document.querySelector('#someSection');

observer.observe(target);

CristinaSolana

<picture>
    <source media="(min-width: 1200px)"
        srcset="https://res.cloudinary.com/demo/image/upload/c_scale,w_900,dpr_auto,f_auto/sample.jpg">
    <source media="(min-width: 900px)"
        srcset="https://res.cloudinary.com/demo/image/upload/c_scale,w_600,dpr_auto,f_auto/sample.jpg">
    <img src="https://res.cloudinary.com/demo/image/upload/c_scale,w_300,dpr_auto,f_auto/sample.jpg">
</picture>

CristinaSolana

// Global Vars

$basefontsize: 16 !default;

// Mixins

// input pixel value unitless: 8 vs 8px
// ex. @include rem(padding, 8 12 16 24)

@mixin rem($property, $px: $basefontsize) {

CristinaSolana

1. Clone your fork:

git clone git@github.com:YOUR-USERNAME/YOUR-FORKED-REPO.git

2. Add remote from original repository in your forked repository:

cd into/cloned/fork-repo
git remote add upstream git://github.com/ORIGINAL-DEV-USERNAME/REPO-YOU-FORKED-FROM.git
git fetch upstream