Change dropdown fields background colour upon checkbox click

I'm making multiple fields with drop downs in them. When I click my checkbox to disable the fields, the dropdown fields have a lighter colour on both the text field background and the text itself when compared to the text (non-dropdown) fields. Any idea how to make the colours as the same?

My code looks like this:

        <form
          v-on:submit.prevent
          :disabled="isDisabled(option)"
        >
          <div class="right">
           <button class="button default link small">
            <input
              type="checkbox"
              v-model="index.Enabled"
              @change="formUpdated('', index)"
            >
            <label :for="`status-${index}`">Enabled</label>
           </button>
         </div>

          <div class="row">
              <label class="bold">thing</label>
            </div>
            <div class="clg5 cmd6 csm8 cxs12">
              <select v-model="thing.thing2"
                :disabled="isDisabled(option)"
                @keydown.enter="$event.stopPropagation()"
              >
                <option disabled value="">Please select one</option>
                <option>option 1</option>
                <option>option 2</option>
              </select>
            </div>
          </div>
         </form>