<div id="app">
  <div class="navigation">
    <ul>
      <li v-for="(link, index) in links">
        <a :href="link.url">
          {{ link.text }}
        </a>
        <span class="removeHover">
            <button @click="removeLink(index)">X</button>
          </span>
      </li>
    </ul>
  </div>
  <div class="navigation--input">
    <label for="" >Link Title</label>
    <input v-model="newLink" type="text">
    <label for="">Link URL</label>
    <input v-model="newURL" @keyup.enter="addLink" type="text">
    <span class="error" v-if="isEmpty" v-model="error">Error! {{ error}}</span>
    <button @click="addLink">Add to Navigation</button>
  </div>
</div>

body {
  padding: 0;
  margin: 0;
}
.navigation {
  background-color: #ddd;
  width: 100%;
  margin: 0;
  
  ul {
    margin: 0;
    padding: 20px 0;
    text-align:center;
  }
  
  li {
    display: inline-block;
    padding: 0 20px;
    position: relative;
    
    a {
      color: #555;
      text-decoration: none;
      
      &:hover {
        border-bottom: 2px solid;
      }
    }
  }
  
  &--input {
    width: 20%;
    text-align: center;
    padding: 40px 0;
    margin: 0 auto;
    
    input {
      margin: 10px auto 0 auto;
      border-radius: 5px;
      border: 1px solid #ddd;
      padding: 5px;
      display: block;
      width: 100%;
    }
    
    button {
      margin-top: 20px;
      background-color: cornflowerblue;
      padding: 10px 24px;
      border-radius: 3px;
      color: #fff;
      transition: all .3s ease-out;
      
      &:hover {
        background-color: navy;
      }
    }
    
    label {
      text-align: left;
      display: block;
      &:not(:first-child){
        margin-top: 20px;
      }
    }
  }
}
.removeHover {
    opacity: 0;
    z-index: 2;
    transition: all .3s ease-out;
    // &:hover {
    //   opacity: 1;
    // }
  li:hover &{
        opacity: 1;
      }
  
    button {
      position: absolute;
      text-align: center;
      border-radius: 50%;
      background-color: lightcoral;
      color: #fff;
      font-size: .5em;
      top: 0;
      right: 0;
      margin-top: -11px;
      padding: 5px;
      outline: none;
      &:hover {
        background-color: coral;
      }
  }
}

.error {
    width: 100%;
    display: block;
    background-color: #ff000029;
    padding: 10px 5px;
  margin-top: 14px;
  border-radius: 3px;
}

new Vue({
  el: '#app',
  data: {
    isEmpty: false,
    error: '',
    newLink: '',
    newURL: '',
    links: [
      { text: 'Home', url: 'http://google.com' },
      { text: 'Work', url: 'http://dribbble.com'},
      { text: 'Blog', url: 'http://medium.com'},
      { text: 'Test', url: 'ham' }
    ]
  },
  methods: {
    addLink: function() {
      
      var text = this.newLink.trim()
      var url = this.newURL.trim()
      
      if ((text !== '') && (url !== '')) {
        this.isEmpty = false
        this.links.push({ text: text, url: url })
        this.newLink = ""
        this.newURL = ""
        
      } else {
        this.isEmpty = true
        this.error = 'Complete all boxes!'
      }
    },
    removeLink: function(index) {
      this.links.splice(index, 1)
    }
  }
})