client/src/components/Board.vue

   1 <script>
   2 import { getSquareId, getSquareFromId } from "@/utils/squareId";
   3 import { ArrayFun } from "@/utils/array";
   4 import { store } from "@/store";
   5 export default {
   6   name: "my-board",
   7   // Last move cannot be guessed from here, and is required for highlights.
   8   // vr: object to check moves, print board...
   9   // userColor is left undefined for an external observer
  10   props: [
  11     "vr",
  12     "lastMove",
  13     "analyze",
  14     "score",
  15     "incheck",
  16     "orientation",
  17     "userColor",
  18     "vname"
  19   ],
  20   data: function() {
  21     return {
  22       mobileBrowser: ("ontouchstart" in window),
  23       possibleMoves: [], //filled after each valid click/dragstart
  24       choices: [], //promotion pieces, or checkered captures... (as moves)
  25       selectedPiece: null, //moving piece (or clicked piece)
  26       start: null, //pixels coordinates + id of starting square (click or drag)
  27       startArrow: null,
  28       movingArrow: { x: -1, y: -1 },
  29       arrows: [], //object of {start: x,y / end: x,y}
  30       circles: {}, //object of squares' ID --> true (TODO: use a set?)
  31       click: "",
  32       clickTime: 0,
  33       settings: store.state.settings
  34     };
  35   },
  36   render(h) {
  37     if (!this.vr) {
  38       // Return empty div of class 'game' to avoid error when setting size
  39       return h("div", {
  40         class: {
  41           game: true
  42         }
  43       });
  44     }
  45     const [sizeX, sizeY] = [V.size.x, V.size.y];
  46     // Precompute hints squares to facilitate rendering
  47     let hintSquares = ArrayFun.init(sizeX, sizeY, false);
  48     this.possibleMoves.forEach(m => {
  49       hintSquares[m.end.x][m.end.y] = true;
  50     });
  51     // Also precompute in-check squares
  52     let incheckSq = ArrayFun.init(sizeX, sizeY, false);
  53     this.incheck.forEach(sq => {
  54       incheckSq[sq[0]][sq[1]] = true;
  55     });
  56
  57     const lm = this.lastMove;
  58     const showLight = (
  59       this.settings.highlight &&
  60       ["all","highlight"].includes(V.ShowMoves)
  61     );
  62     const showCheck = (
  63       this.settings.highlight &&
  64       ["all","highlight","byrow"].includes(V.ShowMoves)
  65     );
  66     const orientation = !V.CanFlip ? "w" : this.orientation;
  67     // Ensure that squares colors do not change when board is flipped
  68     const lightSquareMod = (sizeX + sizeY) % 2;
  69     const showPiece = (x, y) => {
  70       return (
  71         this.vr.board[x][y] != V.EMPTY &&
  72         (!this.vr.enlightened || this.analyze || this.score != "*" ||
  73           (!!this.userColor && this.vr.enlightened[this.userColor][x][y]))
  74       );
  75     };
  76     const inHighlight = (x, y) => {
  77       return showLight && !!lm && (
  78         (lm.end.x == x && lm.end.y == y) ||
  79         (lm.start.x == x && lm.start.y == y));
  80     };
  81     const inShadow = (x, y) => {
  82       return (
  83         !this.analyze &&
  84         this.score == "*" &&
  85         this.vr.enlightened &&
  86         (!this.userColor || !this.vr.enlightened[this.userColor][x][y])
  87       );
  88     };
  89     // Create board element (+ reserves if needed by variant)
  90     let elementArray = [];
  91     const gameDiv = h(
  92       "div",
  93       {
  94         "class": {
  95           game: true,
  96           clearer: true
  97         }
  98       },
  99       [...Array(sizeX).keys()].map(i => {
 100         const ci = orientation == "w" ? i : sizeX - i - 1;
 101         return h(
 102           "div",
 103           {
 104             "class": {
 105               row: true
 106             },
 107             style: { opacity: this.choices.length > 0 ? "0.5" : "1" }
 108           },
 109           [...Array(sizeY).keys()].map(j => {
 110             const cj = orientation == "w" ? j : sizeY - j - 1;
 111             const squareId = "sq-" + ci + "-" + cj;
 112             let elems = [];
 113             if (showPiece(ci, cj)) {
 114               elems.push(
 115                 h("img", {
 116                   "class": {
 117                     piece: true,
 118                     ghost:
 119                       !!this.selectedPiece &&
 120                       this.selectedPiece.parentNode.id == squareId
 121                   },
 122                   attrs: {
 123                     src:
 124                       "/images/pieces/" +
 125                       this.vr.getPpath(
 126                         this.vr.board[ci][cj],
 127                         // Extra args useful for some variants:
 128                         this.userColor,
 129                         this.score,
 130                         this.orientation) +
 131                       V.IMAGE_EXTENSION
 132                   }
 133                 })
 134               );
 135             }
 136             if (this.settings.hints && hintSquares[ci][cj]) {
 137               elems.push(
 138                 h("img", {
 139                   "class": {
 140                     "mark-square": true
 141                   },
 142                   attrs: {
 143                     src: "/images/mark.svg"
 144                   }
 145                 })
 146               );
 147             }
 148             if (!!this.circles[squareId]) {
 149               elems.push(
 150                 h("img", {
 151                   "class": {
 152                     "circle-square": true
 153                   },
 154                   attrs: {
 155                     src: "/images/circle.svg"
 156                   }
 157                 })
 158               );
 159             }
 160             const lightSquare = (ci + cj) % 2 == lightSquareMod;
 161             return h(
 162               "div",
 163               {
 164                 "class": {
 165                   board: true,
 166                   ["board" + sizeY]: true,
 167                   "light-square": lightSquare,
 168                   "dark-square": !lightSquare,
 169                   [this.settings.bcolor]: true,
 170                   "in-shadow": inShadow(ci, cj),
 171                   "highlight-light": inHighlight(ci, cj) && lightSquare,
 172                   "highlight-dark": inHighlight(ci, cj) && !lightSquare,
 173                   "incheck-light":
 174                     showCheck && lightSquare && incheckSq[ci][cj],
 175                   "incheck-dark":
 176                     showCheck && !lightSquare && incheckSq[ci][cj]
 177                 },
 178                 attrs: {
 179                   id: getSquareId({ x: ci, y: cj })
 180                 }
 181               },
 182               elems
 183             );
 184           })
 185         );
 186       })
 187     );
 188     if (!!this.vr.reserve) {
 189       const playingColor = this.userColor || "w"; //default for an observer
 190       const shiftIdx = playingColor == "w" ? 0 : 1;
 191       let myReservePiecesArray = [];
 192       for (let i = 0; i < V.RESERVE_PIECES.length; i++) {
 193         const qty = this.vr.reserve[playingColor][V.RESERVE_PIECES[i]];
 194         myReservePiecesArray.push(
 195           h(
 196             "div",
 197             {
 198               "class": { board: true, ["board" + sizeY]: true },
 199               attrs: { id: getSquareId({ x: sizeX + shiftIdx, y: i }) },
 200               style: { opacity: qty > 0 ? 1 : 0.35 }
 201             },
 202             [
 203               h("img", {
 204                 "class": { piece: true, reserve: true },
 205                 attrs: {
 206                   src:
 207                     "/images/pieces/" +
 208                     this.vr.getReservePpath(i, playingColor) +
 209                     ".svg"
 210                 }
 211               }),
 212               h("sup", { "class": { "reserve-count": true } }, [ qty ])
 213             ]
 214           )
 215         );
 216       }
 217       let oppReservePiecesArray = [];
 218       const oppCol = V.GetOppCol(playingColor);
 219       for (let i = 0; i < V.RESERVE_PIECES.length; i++) {
 220         const qty = this.vr.reserve[oppCol][V.RESERVE_PIECES[i]];
 221         oppReservePiecesArray.push(
 222           h(
 223             "div",
 224             {
 225               "class": { board: true, ["board" + sizeY]: true },
 226               attrs: { id: getSquareId({ x: sizeX + (1 - shiftIdx), y: i }) },
 227               style: { opacity: qty > 0 ? 1 : 0.35 }
 228             },
 229             [
 230               h("img", {
 231                 "class": { piece: true, reserve: true },
 232                 attrs: {
 233                   src:
 234                     "/images/pieces/" +
 235                     this.vr.getReservePpath(i, oppCol) +
 236                     ".svg"
 237                 }
 238               }),
 239               h("sup", { "class": { "reserve-count": true } }, [ qty ])
 240             ]
 241           )
 242         );
 243       }
 244       const myReserveTop = (
 245         (playingColor == 'w' && orientation == 'b') ||
 246         (playingColor == 'b' && orientation == 'w')
 247       );
 248       // Center reserves, assuming same number of pieces for each side:
 249       const nbReservePieces = myReservePiecesArray.length;
 250       const marginLeft = ((100 - nbReservePieces * (100 / sizeY)) / 2) + "%";
 251       const reserveTop =
 252         h(
 253           "div",
 254           {
 255             "class": {
 256               game: true,
 257               "reserve-div": true
 258             },
 259             style: {
 260               "margin-left": marginLeft
 261             }
 262           },
 263           [
 264             h(
 265               "div",
 266               {
 267                 "class": {
 268                   row: true,
 269                   "reserve-row": true
 270                 }
 271               },
 272               myReserveTop ? myReservePiecesArray : oppReservePiecesArray
 273             )
 274           ]
 275         );
 276       var reserveBottom =
 277         h(
 278           "div",
 279           {
 280             "class": {
 281               game: true,
 282               "reserve-div": true
 283             },
 284             style: {
 285               "margin-left": marginLeft
 286             }
 287           },
 288           [
 289             h(
 290               "div",
 291               {
 292                 "class": {
 293                   row: true,
 294                   "reserve-row": true
 295                 }
 296               },
 297               myReserveTop ? oppReservePiecesArray : myReservePiecesArray
 298             )
 299           ]
 300         );
 301       elementArray.push(reserveTop);
 302     }
 303     elementArray.push(gameDiv);
 304     if (!!this.vr.reserve) elementArray.push(reserveBottom);
 305     const boardElt = document.querySelector(".game");
 306     // boardElt might be undefine (at first drawing),
 307     // but it won't be used in this case.
 308     const squareWidth = (!!boardElt ? boardElt.offsetWidth / sizeY : 42);
 309     if (this.choices.length > 0 && !!boardElt) {
 310       // No choices to show at first drawing
 311       const offset = [boardElt.offsetTop, boardElt.offsetLeft];
 312       const maxNbeltsPerRow = Math.min(this.choices.length, sizeY);
 313       let topOffset = offset[0] + (sizeY / 2) * squareWidth - squareWidth / 2;
 314       let choicesHeight = squareWidth;
 315       if (this.choices.length >= sizeY) {
 316         // A second row is required (Eightpieces variant)
 317         topOffset -= squareWidth / 2;
 318         choicesHeight *= 2;
 319       }
 320       const choices = h(
 321         "div",
 322         {
 323           attrs: { id: "choices" },
 324           "class": { row: true },
 325           style: {
 326             top: topOffset + "px",
 327             left:
 328               offset[1] +
 329               (squareWidth * Math.max(sizeY - this.choices.length, 0)) / 2 +
 330               "px",
 331             width: (maxNbeltsPerRow * squareWidth) + "px",
 332             height: choicesHeight + "px"
 333           }
 334         },
 335         [ h(
 336           "div",
 337           {
 338             "class": { "full-width": true }
 339           },
 340           this.choices.map(m => {
 341             // A "choice" is a move
 342             const applyMove = (e) => {
 343               e.stopPropagation();
 344               // Force a delay between move is shown and clicked
 345               // (otherwise a "double-click" bug might occur)
 346               if (Date.now() - this.clickTime < 200) return;
 347               this.choices = [];
 348               this.play(m);
 349             };
 350             const onClick =
 351               this.mobileBrowser
 352                 ? { touchend: applyMove }
 353                 : { mouseup: applyMove };
 354             return h(
 355               "div",
 356               {
 357                 "class": {
 358                   board: true,
 359                   ["board" + sizeY]: true
 360                 },
 361                 style: {
 362                   width: (100 / maxNbeltsPerRow) + "%",
 363                   "padding-bottom": (100 / maxNbeltsPerRow) + "%"
 364                 }
 365               },
 366               [
 367                 h("img", {
 368                   attrs: {
 369                     src:
 370                       "/images/pieces/" +
 371                       // orientation: extra arg useful for some variants:
 372                       this.vr.getPPpath(m, this.orientation) +
 373                       V.IMAGE_EXTENSION
 374                   },
 375                   "class": { "choice-piece": true },
 376                   on: onClick
 377                 })
 378               ]
 379             );
 380           })
 381         ) ]
 382       );
 383       elementArray.unshift(choices);
 384     }
 385     if (
 386       !this.mobileBrowser &&
 387       (this.arrows.length > 0 || this.movingArrow.x >= 0)
 388     ) {
 389       let svgArrows = [];
 390       const arrowWidth = squareWidth / 4;
 391       this.arrows.forEach(a => {
 392         const endPoint = this.adjustEndArrow(a.start, a.end, squareWidth);
 393         svgArrows.push(
 394           h(
 395             "path",
 396             {
 397               "class": { "svg-arrow": true },
 398               attrs: {
 399                 d: (
 400                   "M" + a.start.x + "," + a.start.y + " " +
 401                   "L" + endPoint.x + "," + endPoint.y
 402                 ),
 403                 style: "stroke-width:" + arrowWidth + "px"
 404               }
 405             }
 406           )
 407         );
 408       });
 409       if (this.movingArrow.x >= 0) {
 410         const endPoint =
 411           this.adjustEndArrow(this.startArrow, this.movingArrow, squareWidth);
 412         svgArrows.push(
 413           h(
 414             "path",
 415             {
 416               "class": { "svg-arrow": true },
 417               attrs: {
 418                 d: (
 419                   "M" + this.startArrow.x + "," + this.startArrow.y + " " +
 420                   "L" + endPoint.x + "," + endPoint.y
 421                 ),
 422                 style: "stroke-width:" + arrowWidth + "px"
 423               }
 424             }
 425           )
 426         );
 427       }
 428       // Add SVG element for drawing arrows
 429       elementArray.push(
 430         h(
 431           "svg",
 432           {
 433             attrs: {
 434               id: "arrowCanvas",
 435               stroke: "none"
 436             }
 437           },
 438           [
 439             h(
 440               "defs",
 441               {},
 442               [
 443                 h(
 444                   "marker",
 445                   {
 446                     attrs: {
 447                       id: "arrow",
 448                       markerWidth: (2 * arrowWidth) + "px",
 449                       markerHeight: (3 * arrowWidth) + "px",
 450                       markerUnits: "userSpaceOnUse",
 451                       refX: "0",
 452                       refY: (1.5 * arrowWidth) + "px",
 453                       orient: "auto"
 454                     }
 455                   },
 456                   [
 457                     h(
 458                       "path",
 459                       {
 460                         "class": { "arrow-head": true },
 461                         attrs: {
 462                           d: (
 463                             "M0,0 L0," + (3 * arrowWidth) + " L" +
 464                             (2 * arrowWidth) + "," + (1.5 * arrowWidth) + " z"
 465                           )
 466                         }
 467                       }
 468                     )
 469                   ]
 470                 )
 471               ]
 472             )
 473           ].concat(svgArrows)
 474         )
 475       );
 476     }
 477     let onEvents = {};
 478     // NOTE: click = mousedown + mouseup
 479     if (this.mobileBrowser) {
 480       onEvents = {
 481         on: {
 482           touchstart: this.mousedown,
 483           touchmove: this.mousemove,
 484           touchend: this.mouseup
 485         }
 486       };
 487     } else {
 488       onEvents = {
 489         on: {
 490           mousedown: this.mousedown,
 491           mousemove: this.mousemove,
 492           mouseup: this.mouseup,
 493           contextmenu: this.blockContextMenu
 494         }
 495       };
 496     }
 497     return h("div", onEvents, elementArray);
 498   },
 499   methods: {
 500     blockContextMenu: function(e) {
 501       e.preventDefault();
 502       e.stopPropagation();
 503       return false;
 504     },
 505     cancelResetArrows: function() {
 506       this.startArrow = null;
 507       this.arrows = [];
 508       this.circles = {};
 509     },
 510     adjustEndArrow: function(start, end, squareWidth) {
 511       // Simple heuristic for now, just remove 1/3 square.
 512       // TODO: should depend on the orientation.
 513       const delta = [end.x - start.x, end.y - start.y];
 514       const dist = Math.sqrt(delta[0] * delta[0] + delta[1] * delta[1]);
 515       const fracSqWidth = squareWidth / 3;
 516       return {
 517         x: end.x - delta[0] * fracSqWidth / dist,
 518         y: end.y - delta[1] * fracSqWidth / dist
 519       };
 520     },
 521     mousedown: function(e) {
 522       e.preventDefault();
 523       if (!this.mobileBrowser && e.which != 3)
 524         // Cancel current drawing and circles, if any
 525         this.cancelResetArrows();
 526       if (this.mobileBrowser || e.which == 1) {
 527         // Mouse left button
 528         if (!this.start) {
 529           // NOTE: classList[0] is enough: 'piece' is the first assigned class
 530           const withPiece = (e.target.classList[0] == "piece");
 531           // Emit the click event which could be used by some variants
 532           this.$emit(
 533             "click-square",
 534             getSquareFromId(withPiece ? e.target.parentNode.id : e.target.id)
 535           );
 536           // Start square must contain a piece.
 537           if (!withPiece) return;
 538           let parent = e.target.parentNode; //surrounding square
 539           // Show possible moves if current player allowed to play
 540           const startSquare = getSquareFromId(parent.id);
 541           this.possibleMoves = [];
 542           const color = this.analyze ? this.vr.turn : this.userColor;
 543           if (this.vr.canIplay(color, startSquare))
 544             this.possibleMoves = this.vr.getPossibleMovesFrom(startSquare);
 545           // For potential drag'n drop, remember start coordinates
 546           // (to center the piece on mouse cursor)
 547           const rect = parent.getBoundingClientRect();
 548           this.start = {
 549             x: rect.x + rect.width / 2,
 550             y: rect.y + rect.width / 2,
 551             id: parent.id
 552           };
 553           // Add the moving piece to the board, just after current image
 554           this.selectedPiece = e.target.cloneNode();
 555           Object.assign(
 556             this.selectedPiece.style,
 557             {
 558               position: "absolute",
 559               top: 0,
 560               display: "inline-block",
 561               zIndex: 3000
 562             }
 563           );
 564           parent.insertBefore(this.selectedPiece, e.target.nextSibling);
 565         } else {
 566           this.processMoveAttempt(e);
 567         }
 568       } else if (e.which == 3) {
 569         // Mouse right button
 570         let elem = e.target;
 571         // Next loop because of potential marks
 572         while (elem.tagName == "IMG") elem = elem.parentNode;
 573         // To center the arrow in square:
 574         const rect = elem.getBoundingClientRect();
 575         this.startArrow = {
 576           x: rect.x + rect.width / 2,
 577           y: rect.y + rect.width / 2,
 578           id: elem.id
 579         };
 580       }
 581     },
 582     mousemove: function(e) {
 583       if (!this.selectedPiece && !this.startArrow) return;
 584       e.preventDefault();
 585       if (!!this.selectedPiece) {
 586         // There is an active element: move it around
 587         const [offsetX, offsetY] =
 588           this.mobileBrowser
 589             ? [e.changedTouches[0].pageX, e.changedTouches[0].pageY]
 590             : [e.clientX, e.clientY];
 591         Object.assign(
 592           this.selectedPiece.style,
 593           {
 594             left: offsetX - this.start.x + "px",
 595             top: offsetY - this.start.y + "px"
 596           }
 597         );
 598       }
 599       else {
 600         let elem = e.target;
 601         // Next loop because of potential marks
 602         while (elem.tagName == "IMG") elem = elem.parentNode;
 603         // To center the arrow in square:
 604         if (elem.id != this.startArrow.id) {
 605           const rect = elem.getBoundingClientRect();
 606           this.movingArrow = {
 607             x: rect.x + rect.width / 2,
 608             y: rect.y + rect.width / 2
 609           };
 610         }
 611       }
 612     },
 613     mouseup: function(e) {
 614       e.preventDefault();
 615       if (this.mobileBrowser || e.which == 1) {
 616         if (!this.selectedPiece) return;
 617         // Drag'n drop. Selected piece is no longer needed:
 618         this.selectedPiece.parentNode.removeChild(this.selectedPiece);
 619         delete this.selectedPiece;
 620         this.selectedPiece = null;
 621         this.processMoveAttempt(e);
 622       } else if (e.which == 3) {
 623         // Mouse right button
 624         this.movingArrow = { x: -1, y: -1 };
 625         this.processArrowAttempt(e);
 626       }
 627     },
 628     processMoveAttempt: function(e) {
 629       // Obtain the move from start and end squares
 630       const [offsetX, offsetY] =
 631         this.mobileBrowser
 632           ? [e.changedTouches[0].pageX, e.changedTouches[0].pageY]
 633           : [e.clientX, e.clientY];
 634       let landing = document.elementFromPoint(offsetX, offsetY);
 635       // Next condition: classList.contains(piece) fails because of marks
 636       while (landing.tagName == "IMG") landing = landing.parentNode;
 637       if (this.start.id == landing.id) {
 638         if (this.click == landing.id) {
 639           // Second click on same square: cancel current move
 640           this.possibleMoves = [];
 641           this.start = null;
 642           this.click = "";
 643         } else this.click = landing.id;
 644         return;
 645       }
 646       this.start = null;
 647       // OK: process move attempt, landing is a square node
 648       let endSquare = getSquareFromId(landing.id);
 649       let moves = this.findMatchingMoves(endSquare);
 650       this.possibleMoves = [];
 651       if (moves.length > 1) {
 652         this.clickTime = Date.now();
 653         this.choices = moves;
 654       } else if (moves.length == 1) this.play(moves[0]);
 655       // else: forbidden move attempt
 656     },
 657     processArrowAttempt: function(e) {
 658       // Obtain the arrow from start and end squares
 659       const [offsetX, offsetY] = [e.clientX, e.clientY];
 660       let landing = document.elementFromPoint(offsetX, offsetY);
 661       // Next condition: classList.contains(piece) fails because of marks
 662       while (landing.tagName == "IMG") landing = landing.parentNode;
 663       if (this.startArrow.id == landing.id)
 664         // Draw (or erase) a circle
 665         this.$set(this.circles, landing.id, !this.circles[landing.id]);
 666       else {
 667         // OK: add arrow, landing is a new square
 668         const rect = landing.getBoundingClientRect();
 669         this.arrows.push({
 670           start: {
 671             x: this.startArrow.x,
 672             y: this.startArrow.y
 673           },
 674           end: {
 675             x: rect.x + rect.width / 2,
 676             y: rect.y + rect.width / 2
 677           }
 678         });
 679       }
 680       this.startArrow = null;
 681     },
 682     findMatchingMoves: function(endSquare) {
 683       // Run through moves list and return the matching set (if promotions...)
 684       return (
 685         this.possibleMoves.filter(m => {
 686           return (endSquare[0] == m.end.x && endSquare[1] == m.end.y);
 687         })
 688       );
 689     },
 690     play: function(move) {
 691       this.$emit("play-move", move);
 692     }
 693   }
 694 };
 695 </script>
 696
 697 <style lang="sass" scoped>
 698 // NOTE: no variants with reserve of size != 8
 699 .game.reserve-div
 700   margin-bottom: 18px
 701 .reserve-count
 702   padding-left: 40%
 703 .reserve-row
 704   margin-bottom: 15px
 705
 706 .full-width
 707   width: 100%
 708
 709 .game
 710   user-select: none
 711   width: 100%
 712   margin: 0
 713   .board
 714     cursor: pointer
 715
 716 #choices
 717   user-select: none
 718   margin: 0
 719   position: absolute
 720   z-index: 300
 721   overflow-y: inherit
 722   background-color: rgba(0,0,0,0)
 723   img
 724     cursor: pointer
 725     background-color: #e6ee9c
 726     &:hover
 727       background-color: skyblue
 728     &.choice-piece
 729       width: 100%
 730       height: auto
 731       display: block
 732
 733 img.ghost
 734   position: absolute
 735   opacity: 0.5
 736   top: 0
 737
 738 #arrowCanvas
 739   pointer-events: none
 740   position: absolute
 741   top: 0
 742   left: 0
 743   width: 100%
 744   height: 100%
 745
 746 .svg-arrow
 747   opacity: 0.65
 748   stroke: #5f0e78
 749   fill: none
 750   marker-end: url(#arrow)
 751
 752 .arrow-head
 753   fill: #5f0e78
 754
 755 .incheck-light
 756   background-color: rgba(204, 51, 0, 0.7) !important
 757 .incheck-dark
 758   background-color: rgba(204, 51, 0, 0.9) !important
 759
 760 .light-square.lichess
 761   background-color: #f0d9b5;
 762 .dark-square.lichess
 763   background-color: #b58863;
 764
 765 .light-square.chesscom
 766   background-color: #e5e5ca;
 767 .dark-square.chesscom
 768   background-color: #6f8f57;
 769
 770 .light-square.chesstempo
 771   background-color: #dfdfdf;
 772 .dark-square.chesstempo
 773   background-color: #7287b6;
 774
 775 // TODO: no predefined highlight colors, but layers. How?
 776
 777 .light-square.lichess.highlight-light
 778   background-color: #cdd26a
 779 .dark-square.lichess.highlight-dark
 780   background-color: #aaa23a
 781
 782 .light-square.chesscom.highlight-light
 783   background-color: #f7f783
 784 .dark-square.chesscom.highlight-dark
 785   background-color: #bacb44
 786
 787 .light-square.chesstempo.highlight-light
 788   background-color: #9f9fff
 789 .dark-square.chesstempo.highlight-dark
 790   background-color: #557fff
 791
 792 </style>