//https://w3c.github.io/mathml-core/#dfn-user-agent-stylesheet

 /* The <math> element */
 math {
   direction: ltr;
   text-indent: 0;
   letter-spacing: normal;
   line-height: normal;
   word-spacing: normal;
   font-family: math;
   font-size: inherit;
   font-style: normal;
   font-weight: normal;
   display: inline math;
   math-shift: normal;
   math-style: compact;
   math-depth: 0;
 }
 math[display="block" i] {
   display: block math;
   math-style: normal;
 }
 math[display="inline" i] {
   display: inline math;
   math-style: compact;
 }

 /* <mrow>-like elements */
 semantics > :not(:first-child) {
   display: none;
 }
 maction > :not(:first-child) {
   display: none;
 }
 merror {
   border: 1px solid red;
   background-color: lightYellow;
 }
 mphantom {
   visibility: hidden;
 }

 /* Token elements */
 mi {
   text-transform: math-auto;
 }

 /* Tables */
 mtable {
   display: inline-table;
   math-style: compact;
 }
 mtr {
   display: table-row;
 }
 mtd {
   display: table-cell;
   /* Centering inside table cells should rely on box alignment properties.
      See https://github.com/w3c/mathml-core/issues/156 */
   text-align: center;
   padding: 0.5ex 0.4em;
 }

 /* Fractions */
 mfrac {
   padding-inline-start: 1px;
   padding-inline-end: 1px;
 }
 mfrac > * {
   math-depth: auto-add;
   math-style: compact;
 }
 mfrac > :nth-child(2) {
   math-shift: compact;
 }

 /* Other rules for scriptlevel, displaystyle and math-shift */
 mroot > :not(:first-child) {
   math-depth: add(2);
   math-style: compact;
 }
 mroot, msqrt {
   math-shift: compact;
 }
 msub > :not(:first-child),
 msup > :not(:first-child),
 msubsup > :not(:first-child),
 mmultiscripts > :not(:first-child),
 munder > :not(:first-child),
 mover > :not(:first-child),
 munderover > :not(:first-child) {
   math-depth: add(1);
   math-style: compact;
 }
 munder[accentunder="true" i] > :nth-child(2),
 mover[accent="true" i] > :nth-child(2),
 munderover[accentunder="true" i] > :nth-child(2),
 munderover[accent="true" i] > :nth-child(3) {
   font-size: inherit;
 }
 msub > :nth-child(2),
 msubsup > :nth-child(2),
 mmultiscripts > :nth-child(even),
 mmultiscripts > mprescripts ~ :nth-child(odd),
 mover[accent="true" i] > :first-child,
 munderover[accent="true" i] > :first-child {
   math-shift: compact;
 }
 mmultiscripts > mprescripts ~ :nth-child(even) {
   math-shift: inherit;
 }