highlighting works when "query_string" is used.

gistfile1.txt

{
  "query": {
    "query_string": {
      "query": "floats lsa light"
    }
  },
  "fields": [
    "dtmPosted",
    "postedBy",
    "url",
    "content",
    "title"
  ],
  "highlight": {
    "tags_schema": "styled",
    "order": "score",
    "number_of_fragments": 3,
    "fragment_size": 150,
    "fields": {
      "title": {},
      "content": {}
    }
  },
  "facets": {
    "price": {
      "range": {
        "field": "price",
        "ranges": [
          {
            "to": 49.99
          },
          {
            "from": 50,
            "to": 99.99
          },
          {
            "from": 100,
            "to": 999.99
          },
          {
            "from": 1000,
            "to": 4999.99
          },
          {
            "from": 5000,
            "to": 9999.99
          },
          {
            "from": 10000
          }
        ]
      }
    },
    "postedBy": {
      "terms": {
        "field": "postedBy",
        "order": "count",
        "size": 30
      }
    },
    "classId": {
      "terms": {
        "field": "classId",
        "order": "count",
        "size": 30
      }
    },
    "tags": {
      "terms": {
        "field": "tags",
        "order": "count",
        "size": 30
      }
    }
  }
}