* {
      margin: 0;
      padding: 0;
      font-family: sans-serif;

    }

    body {
      overflow-x: hidden;
      background-color: rgb(19, 19, 19);

    }



    ul li {
      list-style-type: none;
      color: white;
      display: inline;
      padding: 20px;
      margin-top: 10px;
    }

    .landing-page-logo {
      border-radius: 100%;
      width: 6vw;
      margin-top: 15px;
      margin-left: 35px;
    }

    .landing-page-nav {
      display: flex;
      justify-content: space-between;
    }

    ul {
      padding-top: 30px;
       margin-top: 1%;
    }

    .landing-page-nav-link {
      text-decoration: none;
      color: white;
      cursor: pointer;
    }

    .background-color-a a {
      background-color: black;
      padding: 10px;
      border-radius: 5%;
      padding-left: 20px;
      padding-right: 20px;

    }

    .landing-page-nav-border a {
      color: black;
      padding-top: 10px;
      padding-bottom: 10px;
      background-color: yellow;
      border: 1px solid white;
      border-radius: 24px;
      cursor: pointer;
      padding-right: 20px;
      padding-left: 20px;
    }
    .center {
      display: flex;
      justify-content: center;
      padding-top: 50px;
      color: white;

    }

    .flex {
      display: flex;

    }



    /* button */
    .btn {
      margin: 10px;
      padding: 15px 30px;
      border: none;
      outline: none;
      color: #FFF;
      cursor: pointer;
      position: relative;
      z-index: 0;
      border-radius: 12px;
      margin-top: 1%;
      margin-left: 0px;

    }

    .btn::after {
      content: "";
      z-index: -1;
      position: absolute;
      width: 100%;
      height: 100%;
      background-color: #333;
      left: 0;
      top: 0;
      border-radius: 10px;
    }

    /* glow */
    .btn::before {
      content: "";
      background: linear-gradient(45deg,
          #FF0000, #FF7300, #FFFB00, #48FF00,
          #00FFD5, #002BFF, #FF00C8, #FF0000);
      position: absolute;
      top: -2px;
      left: -2px;
      background-size: 600%;
      z-index: -1;
      width: calc(100% + 4px);
      height: calc(100% + 4px);
      filter: blur(8px);
      animation: glowing 20s linear infinite;
      transition: opacity .3s ease-in-out;
      border-radius: 10px;
      opacity: 0;

    }

    @keyframes glowing {
      0% {
        background-position: 0 0;
      }

      50% {
        background-position: 400% 0;
      }

      100% {
        background-position: 0 0;
      }
    }

    /* hover */
    .btn:hover::before {
      opacity: 1;

    }

    .btn:active:after {
      background: transparent;

    }