CSS not rendering same output in local vs server

[pmarxbraun]

Description

My font size are not the same in local vs server. (I've tried several servers, it's all the same).
My font size are the same running gatsby develop and gatsby serve.

Environment

System:
OS: macOS Mojave 10.14.6
CPU: (4) x64 Intel(R) Core(TM) i5-3210M CPU @ 2.50GHz
Shell: 3.2.57 - /bin/bash
Binaries:
Node: 12.16.3 - ~/.nvm/versions/node/v12.16.3/bin/node
npm: 6.14.8 - ~/.nvm/versions/node/v12.16.3/bin/npm
Languages:
Python: 2.7.10 - /usr/bin/python
Browsers:
Chrome: 86.0.4240.111
Safari: 14.0
npmPackages:
gatsby: ^2.18.12 => 2.18.12
gatsby-background-image: ^1.1.1 => 1.1.1
gatsby-image: ^2.3.1 => 2.3.1
gatsby-plugin-google-tagmanager: ^2.3.10 => 2.3.10
gatsby-plugin-manifest: ^2.4.18 => 2.4.18
gatsby-plugin-mdx: ^1.1.4 => 1.1.4
gatsby-plugin-react-helmet: ^3.3.4 => 3.3.4
gatsby-plugin-sharp: ^2.5.3 => 2.5.3
gatsby-remark-images: ^3.2.1 => 3.2.1
gatsby-source-filesystem: ^2.2.2 => 2.2.2
gatsby-transformer-sharp: ^2.4.3 => 2.4.3
npmGlobalPackages:
gatsby-cli: 2.12.111

My font sizes are declared as such

:root {
  --wechain-main-color: #f1b808;
  --wechain-heading-font: "Epilogue", sans-serif;
  --wechain-font: "Poppins", sans-serif;
  --heading: #2f284c;

  /* body font size */
  --text-base-size: 1em;

  /* type scale */
  --text-scale-ratio: 1.3;
  --text-xs: calc((1em / var(--text-scale-ratio)) / var(--text-scale-ratio));
  --text-sm: calc(var(--text-xs) * var(--text-scale-ratio));
  --text-md: calc(
    var(--text-sm) * var(--text-scale-ratio) * var(--text-scale-ratio)
  );
  --text-lg: calc(var(--text-md) * var(--text-scale-ratio));
  --text-xl: calc(var(--text-lg) * var(--text-scale-ratio));
  --text-xxl: calc(var(--text-xl) * var(--text-scale-ratio));

  --space-unit: 1em;
  --space-xs: calc(0.5 * var(--space-unit));
  --space-sm: calc(0.75 * var(--space-unit));
  --space-md: calc(1.25 * var(--space-unit));
  --space-lg: calc(2 * var(--space-unit));
  --space-xl: calc(3.25 * var(--space-unit));
  --space-xxl: calc(4.75 * var(--space-unit));
  --box-shadow-wechain: 0px 16px 40px rgba(112, 144, 176, 0.2);
}

@media (min-width: 64rem) {
  /* responsive decision applied to all text elements */
  :root {
    --text-base-size: 1em;
    --text-scale-ratio: 1.33;
    --space-unit: 1.25em; /* 👇 this responsive decision affects all margins and paddings */
  }
}

I've tried gatsby clean as well as disabling gatsby-plugin-offline as suggested in #461 with no luck.

Here's the sitelink if you wish to check it.

Thanks for your help

[pmarxbraun]

Any ideas guys ? :-(
I got the same issue event the most basic Gatsby site

I've checked all packages versions, Node(14.15), screen resolution,...
When building on other computers, I don't have this difference.
Thanks