Bold All Titles & Labels in Forms

Looking to bold the labels/titles of all form entry field types. I was provided with this code:

div.title span {
    font-weight: bold !important;
}

Which work for the Checkbox, Phone and Name titles/labels, but the Email, Text and Text area categories of the form did not turn bold with the CSS code provided. To clarify - I do not need the "First Name" & "Last Name" subtitles bolded.

Website:
https://www.coorlasarch.com/design-guide

Thanks in advance for your attention to this,
Stephen

Try removing removing div, it should work: 

.title span {
    font-weight: bold !important;
}