* {
    margin: 0;
    padding: 0;
  
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    -khtml-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
  }
  
  :root {
    --background-color-dark: rgb(28, 28, 28);
    --background-color-light: rgb(216, 216, 216);
    --selected-field-dark: rgba(255, 255, 255, 0.2);
    --selected-field-light: rgba(0, 0, 0, 0.2);
  }
  
  html {
    height: 100%;
  }
  
  body {
    height: 99%;
  
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
  
    font-family: sans-serif;
    font-size: 2rem;
  
    background-color: var(--background-color-dark);
    color: var(--background-color-light);
  }
  
  span#turnt {
    margin-bottom: 1rem;
  }
  
  span#turnb {
    margin-top: 1rem;
    rotate: 180deg;
  }
  
  div#game {
    width: max(20rem, 35vw);
    height: max(20rem, 35vw);
  
    display: grid;
    grid-template-columns: repeat(3, 1fr);
  
    border: 3px var(--background-color-light) solid;
  }
  
  div.field {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
  
    border: 3px var(--background-color-light) solid;
  }
  
  div.cell {
    border: 3px var(--background-color-light) solid;
    transition: background-color 0.2s cubic-bezier(0.165, 0.84, 0.44, 1);
  }
  
  div.cell:not(.locked):not(.red):not(.blue) {
    cursor: pointer;
  }
  
  div.cell:hover:not(.locked):not(.red):not(.blue) {
    background-color: var(--selected-field-dark);
  }
  
  div.locked {
    pointer-events: none;
  
    background-color: rgba(255, 144, 0, 0.1);
  }
  
  div.red {
    background-color: red;
  }
  
  div.blue {
    background-color: blue;
  }
  
  div.field.red > div.cell,
  div.field.blue > div.cell {
    display: none;
  }