This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

firefox defaut css

  • 3 replies
  • 1 has this problem
  • 4 views
  • Last reply by Wayne

more options

I am trying to find out what the actual point sizes are for the H1-H6 headings, as well as the point sizes for the (now-obsolete) font sizes 1-7. I have found the heading information at this link, but it does not tell me what the sizes for font size 1-7 are. I started looking for the location of the default css for the browser in the hopes that it would answer this question. However, the answers on the net are anything but accurate and (I think) apply to some older versions of the browser. Is there a specific css file (or files) that contain the default css settings for FireFox, and if so, where is it/are they located?

I am in the process of converting some older web pages of mine from using font tags to using css instead. Without this information I cannot accurately modify the page as the layout changes as soon as I change a font tag to a css property.

I am trying to find out what the actual point sizes are for the H1-H6 headings, as well as the point sizes for the (now-obsolete) font sizes 1-7. I have found the heading information at this [http://zuga.net/articles/html-heading-elements/ link], but it does not tell me what the sizes for font size 1-7 are. I started looking for the location of the default css for the browser in the hopes that it would answer this question. However, the answers on the net are anything but accurate and (I think) apply to some older versions of the browser. Is there a specific css file (or files) that contain the default css settings for FireFox, and if so, where is it/are they located? I am in the process of converting some older web pages of mine from using font tags to using css instead. Without this information I cannot accurately modify the page as the layout changes as soon as I change a font tag to a css property.

Modified by Wayne

Chosen solution

Thank you both for answering. The question had nothing to do with forms, however. It is about the actual size of the FONT size attributes as compared to the H1-H6 header tags. The second answer was more helpful, but still not what I was looking for. I actually did find an answer by searching the web. I found three sites that each had part of the data I was looking for, and I was able to build a table of the results. From that I was able to see that looking at it from the standpoint of 'em's is the way to determine this. I also found that Firefox's numbers are different from the old FONT size and H1-H6 when using CSS to set the size. It's not always much of a difference, but enough to make the page look different. I am using this table as my guide in converting all of my old pages to HTML5/CSS compliance. I would post it in this message, but it is a html document and I don't know how it would display. It also uses the FONT tag for setting the size of the text for comparison to the H1-H6 tags, so I don't know how well that would go over here.

Read this answer in context 👍 0

All Replies (3)

more options

The :default CSS pseudo-class selects form elements that are the default in a group of related elements.

What this selector matches is defined in HTML Standard §4.16.3 Pseudo-classes — it may match the <button>, <input type="checkbox">, <input type="radio">, and <option> elements:

A default option element is the first one with the selected attribute, or the first enabled option in DOM order. multiple <select>s can have more than one selected option, so all will match :default. <input type="checkbox"> and <input type="radio"> match if they have the checked attribute. <button> matches if it is a <form>’s default submission button: the first <button> in DOM order that belongs to the form. (This also applies to <input> types that submit forms, like image or submit.)

more options

hii wayne


you visit this site for default css settings for FireFox.

Examine and edit CSS - Firefox Developer Tools | MDN I hope it helps.

more options

Chosen Solution

Thank you both for answering. The question had nothing to do with forms, however. It is about the actual size of the FONT size attributes as compared to the H1-H6 header tags. The second answer was more helpful, but still not what I was looking for. I actually did find an answer by searching the web. I found three sites that each had part of the data I was looking for, and I was able to build a table of the results. From that I was able to see that looking at it from the standpoint of 'em's is the way to determine this. I also found that Firefox's numbers are different from the old FONT size and H1-H6 when using CSS to set the size. It's not always much of a difference, but enough to make the page look different. I am using this table as my guide in converting all of my old pages to HTML5/CSS compliance. I would post it in this message, but it is a html document and I don't know how it would display. It also uses the FONT tag for setting the size of the text for comparison to the H1-H6 tags, so I don't know how well that would go over here.