<div id="wrap" class="input">
  <header class="input-header">
    <h1>Input Text/Password Animation</h1>
  </header>
  <section class="input-content">
    <h2>Input Text/Password Animation<span>Only CSS</span></h2>
    <div class="input-content-wrap">
      <dl class="inputbox">
        <dt class="inputbox-title">Input Text</dt>
        <dd class="inputbox-content">
          <input id="input0" type="text" required/>
          <label for="input0">ID</label>
          <span class="underline"></span>
        </dd>
      </dl>
      <dl class="inputbox">
        <dt class="inputbox-title">Input Password</dt>
        <dd class="inputbox-content">
          <input id="input1" type="password" required/>
          <label for="input1">Password</label>
          <span class="underline"></span>
        </dd>
      </dl>
      <div class="btns">
          <button class="btn btn-confirm">Sign In</button>
          <button class="btn btn-cancel">Cancel</button>
      </div>
    </div>
  </section>
</div>

// color vars
$primary-color: #1a237e;
$dark-primary-color: #0f1041;
$accent-color: #2962ff;
$sub-yellow: #ffca00;

//common style
html,body{
  height: 100%;
  background: #e0e0e0;
  font-family:sans-serif;
  font-size:14px;
}
#wrap{
  width: 100%;
  max-width:900px;
  margin:0 auto 60px;
  box-shadow: 0 3px 6px rgba(0,0,0,0.25);
}

//layout
.input{
  &::before{
    content:'';
    display:block;
    position: absolute;
    top:0;
    left:0;
    width: 100%;
    height: 300px;
    background: $dark-primary-color;
  }
  &-header{
    position: relative;
    padding-top:80px;
    color: #fff;
    h1{
      padding-bottom:25px;
      font-size:3.25em;
      font-weight:100;
    }
  }
  &-content{
    position: relative;
    padding:44px 55px;
    background: #fff;
    z-index:10;
    
    h2{
      padding-bottom:45px;
      font-size:1.625em;
      font-weight:bold;
      vertical-align: middle;
      span{
        display: inline-block;
        margin-left:10px;
        padding:5px 6px 3px;
        border:1px solid $sub-yellow;
        border-radius:4px;
        font-size:0.85rem;
        vertical-align: middle;
        color: $sub-yellow;
      }
    }
    .inputbox{
      overflow: hidden;
      position: relative;
      padding:15px 0 28px 200px;
      &-title{
        position: absolute;
        top:15px;
        left: 0;
        width: 200px;
        height: 30px;
        color: #666;
        font-weight: bold;
        line-height: 30px;
      }
      &-content{
        position: relative;
        width: 100%;
        input{
          width: 100%;
          height: 30px;
          box-sizing: border-box;
          line-height: 30px;
          font-size:14px;
          border:0;
          background: none;
          border-bottom:1px solid #ccc;
          outline:none;
          border-radius: 0;
          -webkit-appearance: none;
          &:focus,&:valid{
            &~label{
              color: $accent-color;
              transform: translateY(-20px);
              font-size:0.825em;
              cursor:default;
            }
          }
          &:focus{
            &~.underline{
              width: 100%;
            }
          }
        }
        label{
          position: absolute;
          top:0;
          left:0;
          height: 30px;
          line-height: 30px;
          color:#ccc;
          cursor:text;
          transition: all 200ms ease-out;
          z-index:10;
        }
        .underline{
          content:'';
          display: block;
          position: absolute;
          bottom:-1px;
          left:0;
          width: 0;
          height: 2px;
          background: $accent-color;
          transition: all 200ms ease-out;
        }
      }
    }
    
    .btns{
      padding:30px 0 0 200px;
      .btn{
        display:inline-block;
        margin-right:2px;
        padding: 10px 25px;
        background: none;
        border:1px solid #c0c0c0;
        border-radius:2px;
        color: #666;
        font-size:1.125em;
        outline:none;
        transition: all 100ms ease-out;
        &:hover,&:focus{
          transform: translateY(-3px);
        }
        &-confirm{
        border:1px solid $accent-color;
        background: $accent-color;
        color: #fff;}
      }
    }
  }
}