Katex Boxed Equations

Goal

To render a bordered box with multiple equations.

Background

My previous article about dot products contains some boxed math expressions: some are inline and some take up the whole line.

For inline math, that’s simple: either $\fbox{text}$ or $\boxed{a=1}$ will do. For displayed math, these two KaTeX commands will ignore the newline command \\.

Solution

A simple Google search ‘“katex” AND “box”’ saved the day. It led me to this relevant Stack Overflow question, whose accepted answer suggested the use of custom CSS. I copied the CSS class name boxedmath for my blog.

/* boxed math expressions */
.boxedmath {
  border: 0.0625em solid currentcolor;
  padding: 0.5em;
}

I appended the above section into static/css/custom.css.