CSS

.btn {
  border: 1px solid #333;
  text-align: center;
  padding: 10px;
  font-size: 2em;
  cursor: pointer;
  background-color: red;
  color: white;
}

.btn:hover {
  box-shadow: 3px 3px black;
}

.start {
  position: absolute;
  width: 30%;
  top: 20px;
  left: 35%;
  z-index: 1;
}

.gameArea {
  width: 60%;
  margin: auto;
  border: 1px solid #eee;
}

.cell {
  float: left;
}

.col {
  min-width: 100px;
  width: 19%;
  border: 1px solid #eee;
  padding: 0;
}

.main {
  height: 100vh;
  min-width: 800px;
}

.case {
  position: absolute;
  min-width: 100px;
  width: 10%;
  height: 60px;
  font-family: fantasy;
  font-size: 3em;
  text-align: center;
  padding-top: 40px;
  border: 1px solid #ccc;
  cursor: pointer;
  border-radius: 25px;
}

.sideVal {
  margin: auto;
  position: absolute;
  width: 100px;
  height: 35px;
  border: 1px solid black;
  text-align: center;
  font-size: 1.5em;
  border-radius: 5px;
}

.close {
  color: #333;
  float: right;
  font-size: 2em;
  font-weight: bold;
}

.close:hover {
  color: red;
  text-decoration: none;
  cursor: pointer;
}

.modal1,
.modal2 {
  display: none;
  position: fixed;
  background-color: rgb(0, 0, 0);
  background-color: rgba(0, 0, 0, 0.4);
  width: 100%;
  height: 100%;
  left: 0;
  top: 0;
  padding-top: 120px;
  z-index: 1;
}

.modal-content {
  background-color: #eee;
  margin: auto;
  min-height: 200px;
  padding: 30px;
  width: 50%;
  border-radius: 15px;
}

.modal-body,
.modal-body2 {
  text-align: center;
  font-size: 2em;
}

.deal {
  background-color: green;
}

.noDeal {
  background-color: red;
}

.offers {
  width: 40%;
  height: 50px;
  font-size: 2em;
  display: inline-block;
  color: white;
  text-align: center;
  padding: 2px;
  margin: 3%;
}

.offers:hover {
  color: aliceblue;
  font-weight: bold;
  cursor: pointer;
}


JavaScript

const app = function () {
  const vals = [100, 2, 3, 4, 5, 6, 7, 8, 10, 15, 20, 40, 50, 75, 1, 200];
  const page = {};
  const game = {};
  let sideVals = [];
  vals.sort(function (a, b) {
    return a - b;
  })
  game.offers = [100, 14, 4, 12, 2, 1].filter(function (x) {
    return x < vals.length;
  })
  game.offers.sort(function (a, b) {
    return b - a;
  })

  function init() {
    page.modal1 = document.querySelector('.modal1');
    page.modal2 = document.querySelector('.modal2');
    page.modalBody = document.querySelector('.modal-body');
    page.modalBody2 = document.querySelector('.modal-body2');
    page.start = document.querySelector('.start');
    page.start.addEventListener('click', startGame);
    page.con = document.querySelector('.gameArea');
    page.main = document.querySelector('.main');
    page.leftSide = document.querySelector('.leftSide');
    page.rightSide = document.querySelector('.rightSide');
    game.inPlay = false;
    document.querySelector('.close').addEventListener('click', closePopUp);
    window.onclick = function (e) {
      if (e.target == page.modal1) {
        closePopUp();
      }
    }
  }

  function closePopUp() {
    page.modal1.style.display = 'none';
    ///add offer logic
  }

  function startGame() {
    console.log('game started');
    page.start.style.display = 'none';
    buildGameBoard();
    game.lastOffer = false;
    game.inPlay = true;
    game.offerMade = 0;
    popUp('<h1>Select a Case</h1>Click any of the below cases');
  }

  function popUp(message) {
    console.log(message);
    page.modal1.style.display = "block";
    page.modalBody.innerHTML = message;
  }

  function buildGameBoard() {
    //build board  
    sideVal = [];
    const val2 = vals.slice(0);
    page.con.innerHTML = "";
    game.holdingArray = [];
    page.main.style.width = window.innerWidth + 'px';
    let tempCon = page.con.getBoundingClientRect();
    console.log(tempCon);
    let tempSide = page.rightSide.getBoundingClientRect();
    let spacer = (tempCon.width / 4) - 10;
    let ver = tempCon.top + 10;
    let hor = tempCon.left - (spacer / 1.2);
    let sideTop = 0;
    let leftHor = tempSide.width / 3;
    for (let x = 0; x < vals.length; x++) {
      sideVal[x] = document.createElement('div');
      sideVal[x].classList.add('sideVal');
      sideVal[x].textContent = vals[x];
      if (x == Math.round(vals.length / 2)) {
        sideTop = 0;
        leftHor = tempSide.left + (tempSide.width / 3);
      }
      sideVal[x].style.left = leftHor + 'px';
      sideVal[x].style.top = sideTop + 'px';
      sideTop += 40;
      if (x < (vals.length / 2)) {
        page.leftSide.appendChild(sideVal[x]);
      }
      else {
        page.rightSide.appendChild(sideVal[x]);
      }
      let maker = document.createElement('div');
      let ranIndex = Math.floor(Math.random() * val2.length);
      let temp = val2.splice(ranIndex, 1)[0];
      console.log(temp);
      console.log(val2);
      hor += spacer;
      maker.val = temp;
      maker.ind = x + 1;
      maker.classList.add('case');
      maker.textContent = x + 1;
      maker.style.left = hor + 'px';
      maker.style.top = ver + 'px';
      maker.addEventListener('click', checkCase);
      page.con.appendChild(maker);
      if ((x % 4) == 3) {
        ver += 130;
        hor = tempCon.left - (spacer / 1.2);
      }
    }

    function checkCase(e) {
      console.log(e.target.val);
    }
  }
  return {
    init: init
  }
}();
document.addEventListener('DOMContentLoaded', app.init);