style.css

* {
    color: white;
    font-family: sans-serif;
    transition: 0.2s ease-in-out;
    user-select: none;
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

.align {
    display: flex;
    justify-content: center;
    align-items: center;
}

body {
    width: 100vw;
    text-align: center;
    padding-top: 5vh;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: #000;
}


section {
    position: absolute;
    width: 100vw;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 2px;
    flex-wrap: wrap;
    overflow: hidden;
  }
  section::before {
    content: "";
    position: absolute;
    width: 100%;
    height: 100%;
    background: linear-gradient(#000, #0f0, #000);
    animation: animate 5s linear infinite;
  }
  
  @keyframes animate {
    0% {
      transform: translateY(-100%);
    }
    100% {
      transform: translateY(100%);
    }
  }
  
  section span {
    position: relative;
    display: block;
    width: calc(6.25vw - 2px);
    height: calc(6.25vw - 2px);
    background: #181818;
    z-index: 0;
    transition: 1.5s;
    text-align: center;
  }
  
  section span:hover {
    background: #0f0;
    transition: 0s;
  }
  
  section .outerbox {
    position: absolute;
    width: 340px;
    height: 100%;
    background: #333333;
    z-index: 1000;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 40px;
    border-radius: 4px;
    box-shadow: 0 15px 35px rgba(0, 0, 0, 9);
    color: rgb(34, 40, 142);
  }
  
  section .outerbox .content {
    position: relative;
    width: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    gap: 10px;
  }

  section .game-container {
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
  }

  section .game-container span {
    margin: 0 10px;
  }

  section .game-container .tic-tac-toe-span {
    position: relative;
    display: block;
    width: calc(6.25vw - 2px);
    height: calc(6.25vw - 2px);
    background: #333333;
    z-index: 0;
    transition: 1.5s;
  }

  section .game-container .tic-tac-toe-span:hover {
    background: #0f0;
    transition: 0s;
  }
  
.turn-container {
    width: 170px;
    height: 80px;
    margin: auto;
    display: grid;
    grid-template-columns: 1fr 1fr;
    grid-template-rows: 1fr 1fr;
    position: relative;
}

.turn-container h3 {
    margin: 0;
    grid-column-start: 1;
    grid-column-end: 3;
}

.turn-container .turn-box {
    border: 3px solid #061d12;
    font-size: 1.6rem;
    font-weight: 700;
}

.turn-container .turn-box:nth-child(even) {
    border-right: none;
}

.bg {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 85px;
    height: 40px;
    background-color: #2568a2;
    z-index: -1;
}

.main-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: repeat(3, 1fr);
    height: 250px;
    width: 250px;
    margin: 30px auto;
    border: 2px solid #06020b;
}

.box {
    cursor: pointer;
    font-size: 2rem;
    font-weight: 700;
    border: 2px solid #0dee0d;
}

.box:hover {
    background-color: #181e17;
}

#play-again {
    background-color: #0f120f;
    padding: 10px 25px;
    border: none;
    font-size: 1.2rem;
    border-radius: 5px;
    cursor: pointer;
    display: none;
}

#play-again:hover {
    padding: 10px 40px;
    background-color: #1b241d;
    color: #299b29;
}