index.css

* {
    padding: 0;
    margin: 0;
    box-sizing: border-box;
    font-family: 'Roboto', sans-serif;
  }
  
  .container {
    position: relative;
    width: 100%;
    min-height: 100vh;
    overflow: hidden;
    background-image: url(https://photoshop-kopona.com/uploads/posts/2019-02/1550441916_32.jpg);
    background-repeat: no-repeat;
    background-size: cover;
  
  }
  
  .container:before {
    content: "";
    position: absolute;
    width: 2000px;
    height: 2000px;
    border-radius: 50%;
    top: -10%;
    right: 48%;
    transform: translateY(-50%);
    z-index: 6;
    transition: 1.8s ease-in-out;
    background: #820f2a;
  }
  
  .forms-container {
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
  }
  
  .signin-signup {
    position: absolute;
    top: 50%;
    left: 75%;
    transform: translate(-50%, -50%);
    width: 50%;
    display: grid;
    grid-template-columns: 1fr;
    z-index: 5;
    transition: 1s 0.7s ease-in-out;
  }
  nav {
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    padding: 0 5rem;
    overflow: hidden;
    grid-column: 1 / 2;
    grid-row: 1 / 2;
    transition: 0.2s 0.7s ease-in-out;
  }
  
  nav.sign-in-form {
    z-index: 2;
  }
  
  nav.sign-up-form {
    z-index: 1;
    opacity: 0;
  }

  .title {
    font-size: 2.2rem;
    color: var(--title);
    margin-bottom: 10px;
  }
  
  .input-field {
    width: 85%;
    height: 55px;
    margin: 10px 0;
    border-radius: 55px;
    display: grid;
    grid-template-columns: 15% 70% 15%;
    padding: 0 0.4rem;
    box-shadow: rgb(0 0 0 / 16%) 0px 1px 4px;
      background: #ffffff26;
  }
  
  input:-webkit-autofill,
  input:-webkit-autofill:hover,
  input:-webkit-autofill:focus,
  input:-webkit-autofill:active {
      transition: background-color 5000s ease-in-out 0s;
  }
  .input-field i {
    text-align: center;
    line-height: 55px;
    color: var(--input-icon);
    font-size: 1.1rem;
  }

  #togglePassword {
    text-align: center;
  }
  
  #toggleReg {
    text-align: center;
  }
  
  .input-field input {
    background: none;
    outline: none;
    border: none;
    line-height: 1;
    font-weight: 600;
    font-size: 1.1rem;
  }
  
  .input-field input::placeholder {
    font-weight: 500;
  }
  
  .btn {
    width: 150px;
    height: 49px;
    border: none;
    outline: none;
    border-radius: 49px;
    cursor: pointer;
    text-transform: uppercase;
    font-weight: 600;
    margin: 10px 0;
    transition: 0.5s;
    background-color: transparent;
    border: 5px solid #820f2a;
    color: black;
    
  }
  
  .btn:hover {
    color: #fff;
    background-color: #820f2a;
  }
  .panels-container {
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    
  }
  
  .panel {
    display: flex;
    flex-direction: column;
    text-align: center;
    z-index: 7;
  }
  
  .left-panel {
    pointer-events: all;
    margin-top: 120px;
  }

  
  .panel .content {
    color: #fff;
  }
  
  .panel h3 {
    font-weight: 600;
    line-height: 1;
    font-size: 1.5rem;
  }
  
  .panel p {
    font-size: 0.95rem;
    padding: 0.7rem 0;
  }
  
  .btn.transparent {
    margin: 0;
    background: none;
    border: 2px solid #fff;
    width: 130px;
    height: 41px;
    font-weight: 600;
    font-size: 0.8rem;
  }
  
  /* ANIMATION */
  
  .container.sign-up-mode:before {
    transform: translate(100%, -50%);
    transition: 10s;
    right: 52%;
  }
  
  .container.sign-up-mode .left-panel .image,
  .container.sign-up-mode .left-panel .content {
    transform: translateX(-800px);
  }
  
  .container.sign-up-mode .left-panel {
    pointer-events: none;
  }
  
  .container.sign-up-mode .signin-signup {
    left: 25%;
  }
  
  .container.sign-up-mode nav.sign-in-form {
    z-index: 1;
    opacity: 0;
  }
  
  .container.sign-up-mode nav.sign-up-form {
    z-index: 2;
    opacity: 1;
  }
  /* MEDIA SCREEN */
  
  @media (max-width: 870px) {
    .container {
      min-height: 800px;
      height: 100vh;
    }
  
    .container::before {
      width: 1500px;
      height: 1500px;
      left: 30%;
      bottom: 68%;
      transform: translateX(-50%);
      right: initial;
      top: initial;
      transition: 2s ease-in-out;
    }
    
    .signup {
      width: 100%;
      left: 50%;
      top: 86%;
      transform: translate(-50%, -100%);
      transition: 1s 0.8s ease-in-out;
    }
    .signin {
      width: 100%;
      left: 50%;
      top: 80%;
      transform: translate(-50%, -100%);
      transition: 1s 0.8s ease-in-out;
    }
  
    .panels-container {
      grid-template-columns: 1fr;
      grid-template-rows: 1fr 2fr 1fr;
     
    }
  
    .panel {
      flex-direction: row;
      align-items: center;
      margin-bottom: 50px;
    }
   img{
     height: 80px;
     width: 150px;
   }
    .panel .content {
      padding-right: 15%;
      transition: 0.9s 0.8s ease-in-out;
    }
  
    .panel h3 {
      font-size: 1.2rem;
    }
  
    .panel p {
      font-size: 0.7rem;
      padding: 0.5rem 0;
    }
  
    .btn.transparent {
      width: 110px;
      height: 35px;
      font-size: 0.7rem;
    }
    .left-panel {
      grid-row: 1 / 2;
        margin:auto;
    }
  
    .container.sign-up-mode:before {
      transform: translate(-50%, 100%);
      bottom: 32%;
      right: initial;
    }
  
    .container.sign-up-mode .left-panel .image,
    .container.sign-up-mode .left-panel .content {
      transform: translateY(-300px);
    }
  
    .container.sign-up-mode .signin-signup {
      top: 5%;
      transform: translate(-50%, 0);
      left: 50%;
    }
  }
  
  @media (max-width: 570px) {
   nav {
      padding: 0 1.5rem;
    }
    .panel .content {
      padding: 0.5rem 1rem;
    }
  
    .panel p {
      opacity: 0;
      padding: 1px;
    }
    .container:before {
      bottom: 75%;
      left: 50%;
    }
    .left-panel{
      margin: auto;
    }
  
    .container.sign-up-mode:before {
      bottom: 24%;
      left: 50%;
    }
  
  }
  
.social-container a {
    padding: 10px;
    text-align: center;
    text-decoration: none;
    margin: 5px 2px;
    border-radius: 50%;
    display: inline-flex;
    justify-content: center;
    margin: 0 5px;
    height: 40px;
    width: 40px;
    font-size: 25px;
}

.fa-facebook {
    background: #3B5998;
    color: white;
}

.fa-twitter {
    background: #55ACEE;
    color: white;
}

.fa-google {
    background: #dd4b39;
    color: white;
}

.fa-linkedin {
    background: #007bb5;
    color: white;
}
#box{
  position: absolute;
  height: 100vh;
  width: 100%;
  z-index: 7;
  display: none;
  transition: 5s;
}

#success{
  background-image: url('https://cdn.dribbble.com/users/2185205/screenshots/7886140/media/90211520c82920dcaf6aea7604aeb029.gif');
  background-position: fixed;
  background-size: cover;
  background-repeat: no-repeat;
  background-position: center;
  height: 300px;
  width: 300px;
  background-color: tomato;
  z-index: 8;
  margin: auto;
  border-radius: 20px;
}
#success h1{
  position: absolute;
  margin: 30px 60px;
}
#success h3{
  position: absolute;
  margin: 230px 40px;
}