How can I change font size in Bootstrap?

Question

I want to resize down my whole Bootstrap project and I can't change font size. I'm using StarAdmin template.

I was trying to change font size in my style.css , but when I update "font-size", the website still apply old values.

html {
    font-family: sans-serif;
    line-height: 1.15;
    -webkit-text-size-adjust: 100%;
    -webkit-tap-highlight-color: rgba(0, 0, 0, 0);
}

article, aside, figcaption, figure, footer, header, hgroup, main, nav, section {
    display: block;
}

body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji";
    font-size: 0.8rem;  // <===== changed value but nothing happend
    font-weight: 400;
    line-height: 1.5;
    color: #212529;
    text-align: left;
    background-color: #fff;
}

I would like to just change "basic" font size to resize my whole webpage.

Answer 1

Add important to all css properties which you want to override
see code for demo

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji";
  font-size: 0.8rem !important;  // <===== Add Important
  font-weight: 400;
  line-height: 1.5;
  color: #212529;
  text-align: left;
  background-color: #fff; }