StickyTableHeadersFix.css

/**

* Makes table headers sticky on small screens for Template:Sticky header
* and MediaWiki:Gadget-StickyTableHeaders.css.
* 
* See documentation:
* {@link https://en.wikipedia.org/wiki/User:Jroberson108/StickyTableHeadersFix}
*/

/**

* Apply Template:Sticky header/styles.css to smaller screens.
*/

@media screen and (max-width: 639px) {

 /**
  * Make top sticky.
  */
 .sticky-header > thead > tr:first-child,
 .sticky-header > caption + tbody > tr:first-child,
 .sticky-header > tbody:first-child > tr:first-child,
 .sticky-header-multi > thead {
   position: sticky; /* Was "static". */
   top: 0;
   z-index: 10;
 }
 /* Timeless overflowed tables not sticky. */
 body.skin-timeless .content-table-wrapper.overflowed .sticky-header > thead > tr:first-child,
 body.skin-timeless .content-table-wrapper.overflowed .sticky-header > caption + tbody > tr:first-child,
 body.skin-timeless .content-table-wrapper.overflowed .sticky-header > tbody:first-child > tr:first-child,
 body.skin-timeless .content-table-wrapper.overflowed .sticky-header-multi > thead {
   position: static; /* Reset to prior. */
 }

 /**
  * Fix scrolling data shows through sticky's transparent background.
  */
 /* Plain table headers. */
 .sticky-header:not(.wikitable),
 .sticky-header-multi:not(.wikitable) {
   background-color: var(--color-inverted, #fff);
 }
 /* Plain table headers. */
 .sticky-header:not(.wikitable) > *, /* For thead, tbody. */
 .sticky-header:not(.wikitable) > thead > tr:first-child,
 .sticky-header:not(.wikitable) > caption + tbody > tr:first-child,
 .sticky-header:not(.wikitable) > tbody:first-child > tr:first-child,
 .sticky-header-multi:not(.wikitable) > thead,
 /* Wikitable and plain table .sorttop rows after sort. */
 .sticky-header-multi > thead {
   background-color: inherit;
 }

 /**
  * Fix missing borders due to sticky position and wikitable collapsed borders.
  * https://bugs.webkit.org/show_bug.cgi?id=128486
  *
  * Skip rare plain table separated borders, which sometimes shows scrolling
  * data through sticky's 2px "border-spacing".
  *
  * Skip very rare Timeless plain table ".mw-datatable" collapsed boarders.
  */
 .sticky-header.wikitable,
 .sticky-header-multi.wikitable {
   border-collapse: separate; /* Was "collapse". */
   border-spacing: 0;
   border-width: 0 1px 1px 0;
 }
 .sticky-header.wikitable td,
 .sticky-header.wikitable th,
 .sticky-header-multi.wikitable td,
 .sticky-header-multi.wikitable th {
   border-width: 1px 0 0 1px;
 }
 body.skin-timeless .content-table-wrapper:not(.overflowed) .sticky-header.wikitable,
 body.skin-timeless .content-table-wrapper:not(.overflowed) .sticky-header-multi.wikitable {
   border-bottom-width: 0.2em;
   padding: 0;
 }
 /* Adjust  borders. */
 .sticky-header.static-row-numbers.wikitable tr::before,
 .sticky-header-multi.static-row-numbers.wikitable tr::before {
   border-left-width: 1px;
 }
 .sticky-header.static-row-numbers.wikitable > thead > tr:first-child::before,
 .sticky-header.static-row-numbers.wikitable > caption + tbody > tr:first-child::before,
 .sticky-header.static-row-numbers.wikitable > tbody:first-child > tr:first-child::before,
 .sticky-header-multi.static-row-numbers.wikitable > thead > tr:first-child::before,
 .sticky-header-multi.static-row-numbers.wikitable > caption + tbody > tr:first-child::before,
 .sticky-header-multi.static-row-numbers.wikitable > tbody:first-child > tr:first-child::before,
 /* Sortbotton #1: all. When supported, consolidate #1-2 to tr:nth-child(1 of .sortbottom)::before */
 .sticky-header.static-row-numbers.wikitable .sortbottom::before,
 .sticky-header-multi.static-row-numbers.wikitable .sortbottom::before {
   border-top-width: 1px;
 }
 /* Sortbottom #2: all minus 1st. */
 .sticky-header.static-row-numbers.wikitable .sortbottom ~ .sortbottom::before,
 .sticky-header-multi.static-row-numbers.wikitable .sortbottom ~ .sortbottom::before {
   border-top-width: 0;
 }
 /* After sort, "tbody:first-of-type" targets "tbody>tr:first-child". */
 .sticky-header.static-row-numbers.wikitable > tbody:first-of-type > tr:not(.static-row-header)::before,
 .sticky-header-multi.static-row-numbers.wikitable > tbody:first-of-type > tr:not(.static-row-header)::before {
   border-bottom-width: 0;
   border-right-width: 0;
 }
 /* Timeless overflowed tables not sticky. */
 body.skin-timeless .content-table-wrapper.overflowed .sticky-header.wikitable,
 body.skin-timeless .content-table-wrapper.overflowed .sticky-header-multi.wikitable {
   border-collapse: collapse; /* Reset to prior. */
   border-width: 1px; /* Reset to prior. */
 }

}

/**

* For small screens, override global CSS so sticky tables works.
*
* Issues on all targeted skins <=639px wide:
* - Windows and Android: when sticky table wider than main content area, table
*   overflowed and its horizontal scroll replaced with page-level, which
*   messes up page layout.
* - Android (some): zoom out for sticky to work causing readability issues.
* - iPhone: no known issues.
*/

@media screen and (max-width: 639px) {

 body:not(.skin-timeless) .sticky-header,
 body:not(.skin-timeless) .sticky-header-multi,
 body:not(.skin-timeless) .jquery-tablesorter,
 body:not(.skin-timeless) .mw-sticky-header {
   display: table; /* Was "block". */
 }
 body.skin-minerva .sticky-header > caption,
 body.skin-minerva .sticky-header-multi > caption,
 body.skin-minerva .jquery-tablesorter > caption,
 body.skin-minerva .mw-sticky-header > caption {
   display: table-caption; /* Was "block". */
 }

}