Bootstrap sass: set font-size-base in em? - css

I have a responsive Bootstrap page with fixed-size divs containing text. To avoid the text overflowing the div as it changes size, I'm using this solution with media queries to change the default font size.
However, the $font-size-base variable in the Bootstrap sass variables is still defined in terms of pixels and therefore stuff using it doesn't obey this scaling. I tried changing the font-size-base to 1em, but this cause a whole cascade of errors of Incompatible units: 'px' and 'em'.
I could basically overwrite the font sizes I need to be variable in my custom sass file, but this seems like kind of a kludgy approach. Is there a cleaner way that I can make Bootstrap use ems for the font size so that it will change according to my media queries?

Related

Should root element font size affect elements other than text?

Learning about rem and try to make whole website responsive.
According to the value of 1rem, should I be scaling:
Font sizes and margins/paddings around text
margins/paddings/size of elements that do not directly contain text like components and images
Does this depend on the layout?
For example, I have an image in a card component. As user increases the font size, image or space around it might stay small next to a larger font.
Should I let this happen or scale image with the font size? I know the setting in the browser only changes font size. On Facebook, for instance, font size from browser settings does not affect the images or component sizes.
Should I then only worry about text?
I think this is entirely based on context/preference but,
Generally yes, if you are using 'em' for padding/margin (which you should be) this will scale automatically however to the font-size of its element.
Depends on the element, text is hard to read for some people as its small lines in unique shapes so this makes the most sense to scale however images and other elements are generally a lot easier to look at. - if the content of the element is something like an icon for button I would probably scale it with text as it is likely to be adjacent to some text so would look weird if the text scaled but the element didn't. Otherwise I would just use responsive web design such as flex/grid to fill the space of a page, this is "scaling" however less for accessibility and more for design.

Is there a way to set the default zoom for bootstrap

I bought a bootstrap 4 admin theme but its sizing (fonts, spacing, images) for desktop is to large was the feedback I got from client.
However if I change the zoom to 70% the sizing of all the elements is exactly what I need.
I want to make the 70% zoom default in the css for desktops but that only keeps it for my browser on my computer. Is there a css setting or other setting that allow me to do it for all computers.
Since the base theme will get updated by the original auhtor often
I have tried changing the css - font size, spacing, image sizes on so many CSS elements but surely there should be an easy way to simulate make it 70%.
You can adjust the css styles of your elements to fit the purpose.
Have a look at the current value and multiply them with 0.7
If the sizing is defined in rem you can just change the html sizes for the content to fit as rem is aquivalent to the sizes of the html wrapper

How to use EMs and percentages for responsive design?

I'm finally learning responsive design and I need to know the best practices for em and percentage units of measurement. If I were to set the font-size of the body to be 10px, would I run into problems down the line declaring all font-sizes em's (1em = 10px, 2.5em = 25px, etc.)?
Also, when is the correct time to use em units vs percentages? Are em units mainly for typography, and then percentages would be used for sizing, margin, padding, etc.?
I love the idea that I can scale font-size proportionally at media queries by changing the body font-size, but I don't think I would want my layout and spacing to shift based on the size of text (or do I?).
It is best practice to allow the browser's font size setting to affect your design–avoid setting the font-size of the body in pixels.
rem units are great for ensuring that everything scales proportionally to the browser font-size. em units are calculated based on the font-size of the parent element so they can become trickier to use when elements are nested. rem is always relative to the font-size of the html element (the root element). If you assume 1rem = 16px and build everything relative to that, then even if the user has set the browser so that 1rem = 20px, for example, then the entire design will scale up accordingly.
With responsive design, it is best practice to define media query "breakpoints" at screen widths where the content starts to become unusable (rather than at arbitrary widths based on popular devices). When your whole site is scaled up or down by the browser's font-size change, you will want the break points to also respect that font-size. However, since Safari treats rem media queries differently than other browsers, it is best to use em for media queries.
ok, first if you want using responsive design, i suggest strongly to you to use a framework like bootstrap or fondation to have a responsive design. You seem newbie in that way and responsivity is a bunch of css and preprocessor for most complicate cases.
But, to answer to your question, we dont resize fonts in media queries for most cases. Set per exemple your fonts in rem. So you must test on many devices your responsivity. By layout you must probably mean divs. Best practice is viweport vw (width) and vh (height) except if you want a proportionnal measure inside annother element. In that case, use %. Rem is better than em cause it is root em. The true size of a font difined in html. When the screen become too small on a device, you must collapsing your menu, and the text on your site must goes down in a div. I can continue like this a while, but like i said, use a framework, faster learning and faster development. Most devs like me use frameworks for their clients.

Increase JUST font size in css for mobiles, without setting a viewport

Normally when I am creating a responsive site, I do the normal thing of setting a viewport to the device width, and creating different layouts for different screen resolutions.
But I'm doing a few tweaks to an old site that has big chunky buttons, default font sizes and a simple layout, and actually it looks quite usable when viewed as a desktop-style fixed-width layout, even on small mobile devices.
Rather than specifying a viewport and completely rewriting all the css to make a series of mobile-friendly versions, I'd really like to just increase the main body element font size a little more for viewing on a screen that is physically small: for this particular layout, this would be very usable - if I could work out how to do it!
Is this what -webkit-text-size-adjust: is for? It seems like it should be an easy thing to tweak, but all my googling turns up full responsive design approaches, which are overkill for this particular small task.
A way to make it is to detect the screen width with javascript using the window.screen.width property, and then apply the styles that you want from there.
Here's an example using jquery, however the same can be achieved with native javascript if you don't want to use a library http://jsfiddle.net/UXV7Z/
You can apply as many filters in resolution as you need, just like you would using media queries
DONT use javascript for such a simple task to accomplish with modern CSS, just use:
font-size: calc(80px - 3vw);
and adjust the values accordingly. That will icrease the size on smaller devices and decrease it on wider devices, which makes sense for buttons and footers and what not, but if you want to decrease the size on smaller width screens for text like large titles that overflow just use:
font-size: calc(25px + 0.35vw);
Once again adjust the values to fit your needs. And see here to view the browser support for the CSS calc() function. All modern updated browsers support it

Rem/Em Confusion

I've been having a play around using em's/rem's today on a new site and have several things i'd like to discuss/ask on here.
For many years I have been totally a pixel based person with a few percentages thrown in when required.
I keep reading that em's and rem's are "the way" the web should be. Fair Enough which is why I gave it a go today.
So, first things first. Are the point of using em's/rem's for dimensions literally just for changing the dimensions of things relative to the main font size?
If so, then for what situation would you change the main font size? I have always set mine to be 16px and worked with it.
I located a Sass mixin that allows me to specify in pixels my dimensions for any property and it outputs it with rem and a pixel based fallback. I tweaked it to my liking first though.
So I then started building the site using the rem mixin for all my dimensions (margin, padding and a few heights). Yes everything scales when I alter the main font size but again, same question as number 2 here.
I used Compass Susy to set my grid up and used em's to specify it's settings, (I normally would have chosen pixels). I set the grid style within Susy to be the magic-grid which makes the grid static when the browser is wider than the grid but entirely flexible on the inside.
Surely everything that I have read about the benefits of using em's can be done using media queries? What do you guys do and most importantly what do the mainstream sites use?
Right, the next two questions are to do with images. I came across two situations today where using em's/rem's with an image somewhere in the equation resulted in a problem.
5a. I had an h2 set to inline block and added padding around and then the rem equivalent of 45px padding on the right. I set the line-height to a unitless value of 1.3. I then set an image to be the background of the h2 to appear over to the right to appear in the padding-right. At the standard base font size of 16px all is fine. However I increase or decrease that font size and the top and bottom of the image crop off. So question 2 again. I see why the image is getting cropped but it's how to deal with the relationship between em's/rem's and images that is bugging me.
5b. I had a div with a height set at the rem equivalent of 200px in height. I then added an image into there which had a height of 200px. The width of the image was set using the susy mixin span-columns to a specific column width and the height was set to auto. When the font size was altered I either ended up with an image too tall or too short. What is the best thing to do in this situation?
I was looking through some of the compass mixins available and for example this one:
#mixin pretty-bullets($bullet-icon, $width: image-width($bullet-icon), $height: image-height($bullet-icon), $line-height: 18px, $padding: 14px) {
margin-left: 0;
li {
padding-left: $padding;
background: image-url($bullet-icon) no-repeat ($padding - $width) / 2 ($line-height - $height) / 2;
list-style-type: none;
}
}
I can't add in all my em/rem stuff in there?
I think the over arching questions are:
Why are em's/rem's required in the first place?
How do you work with them in relation to images?
Any thoughts guys?
There is a lot to say about your post and it would probably be best to start with a few basics:
Why use em or rem units?
Em & rem units are used to size things relatively.
Em units: An em unit in a browser changes relative to it's parent's font-size, whether that is a span, p, div, body or html element. So when using em units for font sizes and for width or height, those dimensions will depend on the current parent's font-size.
Rem units: An rem unit in a browser is relative to the base font-size of the document. If you set that to 16px then 1rem is 16px, 2rem is 32px and so on. This means that you can change the scale of the entire document at a single point and anything that is using that relative measurement is going to increase/decrease accordingly.
The Point: These measurements are 'relative' so the answer to the question, "Why use em or rem units?", is for the em unit, simply use them when you want to size an element in a web page relative to it's parent and for the rem, use them when you want to size an element relative to the document.
That's a simple approach but it puts web design in the right context for the next question...
How should em & rem units be used in design and layout?
The answer to this question is also multifaceted but to put it in simple terms using em, rem or any 'relative' measurement to describe elements in your design is a move away from static pixel based design.
For the most part em, rem & percentages are used for creating flexible layouts and flexible layouts have a whole different approach to the web and using elements within them than pixel based design. For instance, if you have a container that needs to expand relative to the document width and it has an image in it, you'll probably want that image to resize along with the container or situate itself differently depending on the available space.
Here's where we get into 'Responsive' designs and layouts in an attempt to make 'Adaptive' sites & applications and also where Media Queries and other techniques come in.
Personally I use em's almost exclusively for type and margins & padding of elements. Dimensions I describe in percentages and then it's almost always only the widths. There's only so much you can control in a world where the devices, device dimensions and pixel ratios keep doubling every year.
So to sum up, sort of...
1) If you need static dimensions just stick with pixels. There is generally no real benefit to using relative measurements if you need specific fixed dimensions.
2) Em's & rem's are one of many tools and serve their purpose as other tools (pixels) serve theirs. They are a great tool and worth mastering so use them when you need to but only when the problem requires relative sizing.
3) You may want to split those Compass Susy questions into a more specific post and provide some example if you want help with that.
I hope that helps even if it doesn't answer all of the questions you have here.
Cheers
Ems/rems are used to make the site adaptive to different settings on the client end. My browser settings can increase or decrease the font size on your site, and using em/rem allows you to adapt to my settings. It's a trade off - as with everything else in web design - between your pixel-exact control and your willingness to design around change and user control. There is no right answer - but I like to remind myself that the entire technology of the web is weighted towards user control, and any attempt for me to be pixel-anal is fighting against the core technologies.
Ems/rems can be used in media-queries to set breakpoint widths, but they solve a different part of the adaptability formula - font size, rather than screen size. Your Susy grid can now adapt to both at once!
Images are a pain for any kind of responsive/adaptive design work. The same solutions you might use for a fluid layout will help with an em-based layout. Common solutions involve the background-size property (Compass has a mixin for it) and setting html images to a max-width of 100%. See CSS-Tricks Rundown of Handling Flexible Media. I have use this fluid-media mixin to handle the "intrinsic ratios" approach for background images and the like.
But, more often than not, I find a way to design with fewer images. I like that the technology pushes me towards simplicity in that area - so it doesn't bother me.

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