style.css

* {
    box-sizing: border-box;
  }
  
  body {
    margin: 0;
    padding: 0;
    font-family: Arial, Helvetica, sans-serif;
  }
  
  .header {
    position: relative;
    top: -20px;
    width: 100%;
    background-color: #011627;
    color: #fdfffc;
  }
  
  .header h2 {
    padding: 0.5em;
  }
  
  div.n-queen {
    position: absolute;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 70%;
    max-width: 450px;
    /* border: 1px solid red; */
  }
  
  .inputbox {
    position: relative;
    top: 1.5em;
    bottom: 2em;
  }
  
  .numberbox {
    width: 100%;
    font-size: 14px;
    padding: 4px;
    border: none;
    border-bottom: 2px solid #2ec4b6;
    outline: none;
    background: transparent;
  }
  
  .inputbox label {
    position: absolute;
    top: 4px;
    left: 0px;
    color: #2ec4b6;
    font-size: 14px;
    pointer-events: none;
    transition: 0.3s;
  }
  
  .inputbox input:focus ~ label,
  .inputbox input:disabled ~ label,
  .inputbox input:valid ~ label {
    top: -9px;
    font-size: 12px;
    font-weight: 400;
  }
  
  .slider-container {
    position: absolute;
    left: 5%;
    width: 90%;
    /* text-align: center; */
    margin: 0 auto;
    top: 4em;
    /* border: 2px solid red; */
  }
  
  .slider {
    -webkit-appearance: none;
    width: 100%;
    margin: 0 auto;
    height: 7px;
    border-radius: 7px;
    background: linear-gradient(90deg, #e8eddf 60%, #e8eddf 60%);
    outline: none;
  }
  
  .slider::after {
    content: "SLOW";
    position: absolute;
    top: -10px;
    font-size: 14px;
    font-weight: 500;
    color: #fa7921;
  }
  
  .slider::before {
    content: "FAST";
    position: absolute;
    top: -10px;
    right: 0px;
    font-size: 14px;
    font-weight: 500;
    color: #fa7921;
  }
  
  /* Google chrome */
  .slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 20px;
    height: 20px;
    position: relative;
    top: -2px;
    cursor: pointer;
    background-color: #fa7921;
    border-radius: 50%;
    z-index: 2;
  }
  
  .slider::-webkit-slider-runnable-track {
    -webkit-appearance: none;
    height: 15px;
    width: 15px;
    z-index: 1;
    color: #ffba08;
  }
  
  /* Mozilla firefox */
  .slider::-moz-range-thumb {
    width: 20px;
    height: 20px;
    background-color: #fa7921;
    cursor: pointer;
    position: relative;
    top: -2px;
    border-radius: 50%;
    z-index: 2;
  }
  
  .slider::-webkit-slider-thumb:hover {
    box-shadow: 0 0 0 2px white, 0 0 0 4px #fa7921;
  }
  
  #progress-bar {
    width: 60%;
    height: 7px;
    background: #ffd200;
    border-radius: 7px;
    position: absolute;
    top: 7px;
  }
  
  .play-button {
    position: relative;
    top: 80px;
    left: 35%;
    border: none;
    outline: none;
    color: #fdfffc;
    width: 80px;
    height: 35px;
    background-color: #f72585;
    border-radius: 10px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease-in-out;
    /* z-index: 1; */
  }
  
  .play-button:hover {
    opacity: 0.8;
    transform: scale(1.05);
  }
  
  .queen-arrangement {
    position: relative;
    top: 140px;
    text-align: center;
    font-size: 18px;
    font-weight: 500;
    color: #247ba0;
  }
  
  #n-queen-board {
    position: relative;
    display: flex;
    width: 80%;
    top: 150px;
    margin: 0 auto;
    flex-wrap: wrap;
    justify-content: center;
  }
  
  #n-queen-board div {
    position: relative;
    display: flex;
    justify-content: center;
    flex-direction: column;
    margin: 0 10px;
    box-shadow: 0 4px 8px 0 rgb(0, 0, 0, 0.2);
    border-radius: 3px;
    bottom: 10px;
  }
  
  table {
    position: relative;
    border-collapse: collapse;
    margin: -10px 10px;
    padding: 10px;
    margin-bottom: 10px;
    align-self: center;
  }
  
  td {
    width: 35px;
    height: 35px;
    text-align: center;
  }
  
  h4 {
    position: relative;
    top: -5px;
    padding: 8px;
    width: 95%;
    background-color: #0582ca;
    align-self: center;
    color: #fdfffc;
    text-align: center;
    border-radius: 4px 4px 0 0;
  }