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CSS

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HTML 

              
                h1
  = "Example for "
  a(href="https://kizu.dev/counters-and-stones/", target="_blank") my article
  = " about counters logic in CSS."

//- Variables shoule be odd, not all render ok,
//- but 3x3, 13x13, 15x15, 19x19 are fine
//- (those > 13x13 can be buggy in Edge)
- const rows = 13;
- const columns = 13;
- const winCombo = 5;

form.board(style=`--rows:${rows};--columns:${columns}`)
  - for (var i = 1; i <= rows * columns; i++)
    input(id=`Black${i}`, type='radio', style=`--stone:B${i};--notstone:W${i}`)
  - for (var i = 1; i <= rows * columns; i++)
    input(id=`White${i}`, type='radio', style=`--stone:W${i};--notstone:B${i}`)
  header
    p
      = 'Current turn: '
      span
      
    button(type='reset') Restart
  section
    - for (var i = 1; i <= rows * columns; i++)
      label(for=`Black${i}`, style=`--stone:B${i}`): span
  section
    - for (var i = 1; i <= rows * columns; i++)
      label(for=`White${i}`, style=`--stone:W${i}`): span
  footer
    button(type='reset') Play again!

//- Here we have selectors which should has parts based on the board dimensions
//- and the number of stones in a row required to win.
//- I generate those selectors there so you'd need to change only the variables here and leave everything else to CSS.
- let check1 = ''
- let check2 = ''
- for (var i = 1; i < winCombo; i++)
  - check1 += `:not(:nth-child(${ columns }n-${ i - 1 }))`
  - check2 += `:not(:nth-child(${ columns }n+${ i }))`

style.
  /* ⋯ */ #{ check1 }[id^=W]:checked #{' + :checked'.repeat(winCombo - 1)} ~ footer,
  /* ⋰ */ #{ check2 }[id^=W]:checked #{ ('+' + '*+'.repeat(columns - 2) + ':checked').repeat(winCombo - 1) } ~ footer,
  /* ⋮  */ [id^=W]:checked #{ ('+' + '*+'.repeat(columns - 1) + ':checked').repeat(winCombo - 1) } ~ footer,
  /* ⋱ */ #{ check1 }[id^=W]:checked #{ ('+' + '*+'.repeat(columns) + ':checked').repeat(winCombo - 1) } ~ footer {
    --endgame: grid;
    --endmessage: 'White won!';
  }

  /* ⋯ */ #{ check1 }#{':checked + '.repeat(winCombo - 1)} [id^=B]:checked ~ footer,
  /* ⋰ */ #{ check2 }#{ (':checked+' + '*+'.repeat(columns - 2)).repeat(winCombo - 1) } [id^=B]:checked ~ footer,
  /* ⋮  */ #{ (':checked+' + '*+'.repeat(columns - 1)).repeat(winCombo - 1) } [id^=B]:checked ~ footer,
  /* ⋱ */ #{ check1 }#{ (':checked+' + '*+'.repeat(columns)).repeat(winCombo - 1) } [id^=B]:checked ~ footer {
    --endgame: grid;
    --endmessage: 'Black won!';
  }
!

CSS 

              
                /* Turn-passing counters magic omg */
.board > input {
  counter-increment: var(--stone) 10;
}
.board > input:checked {
  counter-increment: White 10 Black -10 var(--stone) 100 var(--notstone) -10;
}
.board > input[id^=White]:checked {
  counter-increment: White -10 Black 10 var(--stone) 100 var(--notstone) -10;
}

.board {
  --stone-size: 30px;
  --playfield-width: calc(var(--columns) * var(--stone-size));
  --playfield-height: calc(var(--rows) * var(--stone-size));

  counter-reset: White 0 Black 10;
}

/* Visually hiding inputs */
.board > input {
  position: fixed;
  top: -99em;
  left: -99em;
  clip: rect(1px,1px,1px,1px);
  width: 1px;
  height: 1px;
  opacity: 0;
}

/* Stones! */
.board > section > label {
  visibility: hidden;

  position: relative;

  display: flex;
  flex-wrap: wrap;

  box-sizing: border-box;
  height: var(--stone-size);
  width: var(--stone-size);

  cursor: pointer;

  font-size: var(--stone-size);
}
.board > section > label > span,
.board > section > label > span:before {
  visibility: visible;
  content: '';

  position: relative;

  display: flex;
  flex-wrap: wrap;
  flex-grow: 1;

  width: 0;
  height: var(--stone-size);
}
.board > section > label:hover > span:before {
  width: var(--stone-size);
}
.board > section > label > span:before {
  border-radius: 50%;
  box-shadow:
    inset -0.3em -0.1em 0.8em 0em #000,
    inset -.2em -0.3em 0.4em 0.25em #000,
    inset 1em 0 #AAA;
  background: rgba(0,0,0,0.5);
  transform: scale(0.95)
}
.board > section > label[for^=White] > span:before {
  box-shadow:
    inset -1px -1px 1.9px #000,
    inset 1em 0 #FFF;
  background: rgba(0,0,0,0.3);
  transform: scale(0.98)
}
.board > section > label:after,
.board > section > label > span:after {
  content: counter(Black) counter(var(--stone));

  flex-basis: 100%;
  font-size: 10px;
  position: relative;
  padding-left: calc(100% - 3.5ch);
  box-sizing: border-box;
}
.board > section > label[for^=White]:after {
  content: counter(White) counter(var(--stone));
}
.board > section > label > span:after {
  visibility: hidden;
  content: counter(var(--stone));

  padding-left: calc(100% - 2.5ch);
}

/* Layout and other misc stuff */
.board {
  position: relative;

  display: grid;
  grid-template-columns: 1fr min-content 1fr;

  padding: 0;
  margin: auto;
}

/* Label wrappers */
.board > section {
  display: grid;
  grid-column: 2;
  grid-row: 1;
  grid-template-columns: repeat(var(--columns), var(--stone-size));

  width: var(--playfield-width);
  height: var(--playfield-height);
}

/* Turn marker & reset */
.board > header {
  display: flex;
  flex-wrap: wrap;
  padding: var(--stone-size) calc(0.5 * var(--stone-size));
  justify-content: space-between;
  align-items: center;
  grid-column: 2;
  grid-row: 2;
}
.board > header > button {
  visibility: hidden;
}
.board > :checked ~ header > button {
  visibility: inherit;
}

/* Turn marker logic */
.board > header > p {
  margin: 0;
}
.board > header > p > span {
  display: inline-flex;
  flex-wrap: wrap;
  width: var(--stone-size);
  height: var(--stone-size);
  overflow: hidden;
  vertical-align: middle;
  font-size: var(--stone-size);
}
.board > header > p > span:before {
  content: "";
  position: relative;

  flex-grow: 1;

  width: 0;
  height: 100%;

  border-radius: 50%;
  box-shadow:
    inset -1px -1px 1.9px #000,
    inset 1em 0 #FFF;
  background: rgba(0,0,0,0.3);

  transform: scale(0.98)
}
.board > header > p > span:after {
  content: counter(White);

  position: relative;
  flex-basis: 100%;

  box-sizing: border-box;
  height: 100%;
  padding-left: calc(100% - 1.5ch);

  color: transparent;

  border-radius: 50%;
  box-shadow:
    inset -0.3em -0.1em 0.8em 0em #000,
    inset -.2em -0.3em 0.4em 0.25em #000,
    inset 1em 0 #AAA;
  background: rgba(0,0,0,0.5);

  transform: scale(0.95)
}

/* The block with the win message */
.board > footer {
  grid-column: 2;
  grid-row: 1;

  z-index: 99;

  display: var(--endgame, none);

  justify-content: center;
  text-align: center;
  align-content: center;

  grid-gap: 1em;
  margin: calc(-0.5 * var(--stone-size));

  font: 40px/1.5 Hevetica Neue, Arial, sans-serif;
  color: #000;

  background: rgba(255,255,255,0.9);
}
.board > footer:before {
  content: var(--endmessage);
}

/* New game after win button */
.board > footer > button {
  font-size: 1em;
  border: 2px solid;
  padding: 0.5em 1em;
  border-radius: 9em;
  background: #FFF;
  cursor: pointer;
}

/* The board visuals */
.board:before {
  content: "";

  grid-column: 2;
  grid-row: 1;

  width: calc(var(--playfield-width) + var(--stone-size));
  height: calc(var(--playfield-height) + var(--stone-size));
  margin: calc(-0.5 * var(--stone-size));

  --dotsSizeX: calc(var(--stone-size) * (var(--columns) + 1) - var(--stone-size) * 8);
  --dotsSizeY: calc(var(--stone-size) * (var(--rows) + 1) - var(--stone-size) * 8);
  --dotsPositionX: calc(var(--stone-size) * (var(--columns) + 1) / 2);
  --dotsPositionY: calc(var(--stone-size) * (var(--rows) + 1) / 2);
  background:
    radial-gradient(closest-side circle, #000 3px, transparent 4px)
      var(--dotsPositionX) var(--dotsPositionY)/var(--dotsSizeX) var(--dotsSizeY),
    radial-gradient(closest-side circle, #000 3px, transparent 4px)
      50%,
    linear-gradient(#DCB35C calc(var(--stone-size) - 2px), transparent 0)
      0 0/100% calc(var(--stone-size) * var(--rows) + 2px),
    linear-gradient(to right, #DCB35C calc(var(--stone-size) - 2px), transparent 0)
      0 0/calc(var(--stone-size) * var(--columns) + 2px) 100%,
    linear-gradient(#000 var(--stone-size), transparent 0)
      0 0/100% calc(var(--stone-size) * var(--rows)),
    linear-gradient(to right, #000 var(--stone-size), transparent 0)
      0 0/calc(var(--stone-size) * var(--columns)) 100%,
    linear-gradient(#000 2px, transparent 0)
      -1px -1px/var(--stone-size) var(--stone-size),
    linear-gradient(to right, #000 2px, transparent 0)
      -1px -1px/var(--stone-size) var(--stone-size)
    #DCB35C;
}

/* Some visual styles for the page */
html, body {
  padding: 0;
  margin: 0;
}

body {
  min-height: 100vh;
  text-align: center;
}

h1 {
  margin-bottom: 1em;
}
!

JS 

              
                // JS? What JS? HTML & CSS only, yep yep.
!
999px

Console