How do you use em REM CSS?
Basically that both rem and em are scalable and relative units of size, but with em, the unit is relative to the font size of its parent element, while the rem unit is only relative to the root font size of the HTML document. The “r” in rem stands for “root”.
How do you use em units?
0:010:58Should You Use Rem Or Em Units - YouTubeYouTubeStart of suggested clipEnd of suggested clipSo an em is just going to scale based on the current font size while an rem scales off of the rootMoreSo an em is just going to scale based on the current font size while an rem scales off of the root font size so in our example we have a normal container where the font size never changed. So an rem.
How does em font-size work?
An em is a unit of measurement, relative to the size of the font; therefore, in a typeface set at a font-size of 16px, one em is 16px. The em square is the “box” that each glyph is sized relative to. So, at 12 points, the em square is 12 points wide.
Which unit is best for CSS?
Pixels are the most commonly used and accepted unit. And it's considered the base of measurement for many other units. It provides the most consistent result among various devices. The box element in the following example has a height of 150px and width of 150px, and it will remain the same on all screen sizes.
Is em better than px?
Unlike PX, relative units like %, EM, and REM are better suited to responsive design and also help meet accessibility standards. Relative units scale better on different devices because they can scale up and down according to another element's size.
What is em unit based on?
Originally the unit was derived from the width of the capital “M” in the given typeface. The article goes on to explain that although the em unit was originally based on the width of the letter “M”, this is no longer the case, and now the em unit generally refers to the point size of the font.
How is em calculated?
An em is equal to the computed font-size of that element's parent. For example, If there is a div element defined with font-size: 16px then for that div and for its children 1em = 16px . If font-size is not defined explicitly, that element will inherit it from the parent element.
Are em responsive?
The px vs em debate is a long one but em units have proven themselves useful in responsive web design. Using em units should be familiar to most web developers, but worth reviewing. An em unit is a relative unit of measurement based on the parent element.
How many pixels is 1em?
16pxSo, by default 1em = 16px, and 2em = 32px.
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What is the hardest part of CSS?
The hardest thing about using CSS is getting all of the files involved synchronized with each other. There are two ingredients: a web page that refers to the CSS page, and the CSS page that gives the formatting.
What is the purpose of em measurement unit?
The em is simply the font size. In an element with a 2in font, 1em thus means 2in. Expressing sizes, such as margins and paddings, in em means they are related to the font size, and if the user has a big font (e.g., on a big screen) or a small font (e.g., on a handheld device), the sizes will be in proportion.
What is the use of em?
The tag is used to define emphasized text. The content inside is typically displayed in italic. A screen reader will pronounce the words in with an emphasis, using verbal stress.
How are em calculated?
An em is equal to the computed font-size of that element's parent. For example, If there is a div element defined with font-size: 16px then for that div and for its children 1em = 16px . If font-size is not defined explicitly, that element will inherit it from the parent element.
What does em stand for in measurement?
Em is traditionally defined as the width of the uppercase M in the current face and point size. It is more properly defined as simply the current point size. For example, in 12-point type, em is a distance of 12 points.
What About rems and Sass?
The rem unit in CSS always inherits its value from the base font size setting on the root element of the document, irrespective of the computed font size. In HTML, the root element is always the html element. So you could use rems, but this would mean you’ll have to control all components on the page using the font size on that element. It could work on certain projects, but I think this technique works best when focusing the resizability on an isolated component, rather than the whole document.
What is the padding value of 2EM?
The padding value of 2em is equal to 40px (20*2) . As mentioned, this type of calculation would apply to any child elements as well — unless any of those child elements had an explicitly defined font-size value, in which case the em value would be calculated based on that. If no font size is defined anywhere in the CSS, the em unit will be equal to the browser’s default font size for the document, which is usually 16px.
How does font size work in Simurai?
The technique basically works like this: The font-size property is used, as Simurai refers to it, as a “trojan horse”, creating the base unit for the various elements inside our component, or module. Since em units, as described above, are calculated based on the root-defined font-size on the parent element, this makes the entire component easily resizable by simply changing the font-size on the parent element.
What is the teardrop in the top right corner?
The teardrop-like thing in the top right corner is a pseudo-element, which likewise benefits from the base font-size on the parent.
What is an EM unit in CSS?
In CSS, an em unit is equal to the computed font-size for the element to which the em is applied. When em units are declared on child elements that don’t have a font-size defined, they will inherit their font-size from their parent, or from another ancestor element, possibly going all the way back to the root element on the document.
Can you use a preprocessor like Sass?
As for using a preprocessor like Sass, I think that’s a side point. Ultimately, your compiled stylesheet will use whatever units you’re using in your Sass code, and the inheritance will work the same way.
Do you have to use px units to set the root font size?
As described in the discussion on Simurai’s original article, you don’t have to use px units to set the root font-size. You can use ems for that too, but just remember that this will be inherited in the same way from its parent, possibly coming from the document’s default value for font-size.
How big is a font in em?
You could set font-size: 10px on the body, then every 1em is 10px. Then just operate as normal except add the override on child li elements and such. This is how I started using em without changing my way of thinking too much.
Why use px instead of em?
I think the reason many people used px instead of em and still do is because they desire control. They dont want or cant cater for a user setting personal font preferences. It’s very hard to code a design that looks good across many font sizes. The other reason is that px is more reliable (assumption, not 100% sure) in dictating font sizes across different browsers.
How big is a H1 to 2em?
Sizing your h1 to 2em with a body fontsize of 16px will give you the equivalent of 32px as far as I know but I believe it would be better to set your body using percents up front and then changing that percentage within media queries to adapt to different screen sizes. Lets say body { font-size: 100%/1.5 } then h1 { font-size: 3em; 163=48 } h2 { font-size: 2.25em; 162.25=36 }.
Why do I prefer emto rem?
I actually prefer emto rem, because (as you mentioned above) relative space is much easier when using em. Also, by using em, you can easily tie line-height and bottom margin to the font-size (as it shouldbe), not to the root. Congrats on the switch! Your life will (probably) be easier now, I know mine is.
Can ems grow font size?
There are still a few obnoxious things with ems, like the cascading. If you decide that list items should be font-size: 1.1emand then have nested lists, it will cascade and grow the font size of the child lists. You probably didn’t want that. You can fix it with li li { font-size: 1em; }but that’s the kind of thing that can grind your gourd. That’s where rem’s can come in, but that can be tricky as well since there is less browser support (IE 9+).
Can you use media queries to adjust font size?
Hey Becky, you can always use media queries to adjust when you get to smaller font sizes. Even if sizes stay relational as expected, you’ll find that depending on your screen-size/viewport sometimes things need further tweaking anyway.
Do you have to change font size for different screen sizes?
You’re going to need to change font sizes for different screen sizes
What does rem stand for in CSS?
There are several units used by CSS to express length. The older ones, supported by all browsers, are: rem - “r” stands for “root”: “root em” -, which is equal to the font size fixed to the root element (almost always <html> ). vh and vw - Many responsive web design techniques rely heavily on percentage rules.
What is vmin and vmax?
vmin and vmax - These units are related to the maximum or minimum value of vh and vw. For example, if the browser was set to 1200px wide and the height 600px, 1vmin would be 6px and 1vmax would be 12px. However, if the width was set to 700px and the height set to 1080px, vmin would equal 7px and vmax 10.8px.
What is the font size of a paragraph?
A paragraph with font-size: 24px will show up as 24px on a phone, tablet, or desktop screen.
What is vh in CSS?
However, CSS percentage measures are not always the best solution for all problems. The measure vh is equal to 1/100 of the height of the viewport. So, for example, if the height of the browser is 800px, 1vh equals 8px and, similarly, if the width of the viewport is 650px, 1vw is equivalent to 6.5px.
What is length in CSS?
take length. CSS has a way to express length in multiple units. Length is a combination of a number and unit with no whitespace. E.g. 5px, 0.9em etc.
What is the width of the inner pargraph?
Since the parent’s width is 400px, the width of the inner pargraph would be 300px, or 75% of 400px.
What are the two types of units used for CSS?
There are two general kinds of units used for length and size in CSS: relative and absolute.
How many cm should a laser printer be?
On a laser printer, 1cm should be exactly 1 centimeter. But on low-resolution devices, such as computer screens, CSS doesn't require that. And indeed, the result tends to be different from one device to another and from one CSS implementation to another.
What does EM mean in a font?
The em is simply the font size. In an element with a 2in font, 1em thus means 2in. Expressing sizes, such as margins and paddings, in em means they are related to the font size, and if the user has a big font (e.g., on a big screen) or a small font (e.g., on a handheld device), the sizes will be in proportion.
What is the difference between EM and ex units?
It's better to use relative units, such as em, instead. The em and ex units depend on the font and may be different for each element in the document. The em is simply the font size. In an element with a 2in font, 1em thus means 2in.
What is a px in CSS?
The px unit is the magic unit of CSS. It is not related to the current font and usually not related to physical centimeters or inches either. The px unit is defined to be small but visible, and such that a horizontal 1px wide line can be displayed with sharp edges (no anti-aliasing). What is sharp, small and visible depends on the device and the way it is used: do you hold it close to your eyes, like a mobile phone, at arms length, like a computer monitor, or somewhere in between, like an e-book reader? The px is thus not defined as a constant length, but as something that depends on the type of device and its typical use.
What is raster image in CSS?
CSS also defines that raster images (such as photos) are, by default, displayed with one image pixel mapping to 1px. A photo with a 600 by 400 resolution will be 600px wide and 400px high. The pixels in the photo thus do not map to pixels of the display device (which may be very small), but map to px units. That makes it possible to exactly align images to other elements of a document, as long as you use px units in your style sheet, and not pt, cm, etc.
What is high resolution in CSS?
CSS doesn't define what “high resolution” means. But as low-end printers nowadays start at 300 dpi and high-end screens are at 200 dpi, the cut-off is probably somewhere in between.
What is the purpose of the ex unit?
The ex unit is rarely used. Its purpose is to express sizes that must be related to the x-height of a font. The x-height is, roughly, the height of lowercase letters such as a, c, m, or o. Fonts that have the same size (and thus the same em) may vary wildly in the size of their lowercase letters, and when it is important that some image, e.g., matches the x-height, the ex unit is available.
What Are Ems in Css?
When to Use em in CSS
- Em units works well with modular CSS techniques such as component-level styling or encapsulated sections of code in general. For example, they can be used to ensure that a component’s (e.g. a card’s) elements are all sized relative to each other, and allow it to be easily resized. The technique basically works like this: The font-size property is u...
Some Notes, Flaws, etc.
- As you can see from using the range slider in the demo, this type of flexible resizing isn’t always something you’ll want to use. It can be somewhat restricting. You may have to tweak some of the em values to get them how you like, and, as in the case of the parent border in the demo, you may not want the resize-ability to apply to all elements. You can overcome this easily by simply avoid…
What About Rems and Sass?
- The rem unit in CSS always inherits its value from the base font size setting on the root element of the document, irrespective of the computed font size. In HTML, the root element is always the htmlelement. So you could use rems, but this would mean you’ll have to control all components on the page using the font size on that element. It could work on certain projects, but I think this tec…
Conclusion
- As already mentioned, Simurai deserves the credit for making this technique more widely known. Of course, as he mentions, this is nothing new and the basic concept has been used by many experienced developers for years — but maybe not so much in the context of web components, or modules. As Simurai says, I think this is a nice method to use when building a CSS framework o…