You Should Know CSS. My questions to level up your CSS skill

What is the characteristics of the following selector?

The pseudo -function helps the browser to select the highest featured selectioner from the given selector list. In this example, the most featured selector is

:is(#container, .content, main) {
  color: red;
}

<性> The calculation value of the attribute is :is(). Correct or wrong? #container @规则

Pseudo -pseudo -function will make the characteristics zero. Therefore, the color selector's characteristics are higher. This is why the calculation value of the <性> attribute is red.

.container {
  color: red;
}

:where(#container) {
  color: blue;
}

:where() .container If the <如果> attribute of the element is color, then red and

.container {
  display: inline;
  width: 1rem;
  height: 1rem;
  background-color: currentColor;
}

display inline width Case 1: <元> Elements are block -level elements. Their height attributes are equal to the

.child Case 2: <元> Elements are elastic items. Their width attributes are calculated according to the content.

<div class="parent">
  <div class="child"></div>
</div>
<div class="parent-flex">
  <div class="child"></div>
</div>

.parent {
  display: block;
}

.parent-flex {
  display: flex;
}

.child width <<> and width.

value of the .child attribute of the child element to the width replacement value.

In the case of the parent element display and

.parent {
  display: inline-grid;
}

.parent::before {
  content: "";
  display: inline;  
}

.parent::after {
  content: "";
  display: flex;
}

Inside the parent element of <>, the sub -element will be displayed in order in order. Instead, in the case of <情况>, the elements will be displayed one by one. block

<素> What are the calculation values ​​of .child and width attributes of elements? height

:is(#container, .content, main) {
  color: red;
}

.container {
  color: red;
}

:where(#container) {
  color: blue;
}

attribute of the element is equal to the .child attribute of the parent element. Therefore, the calculation value of the width attribute is 1600px. (Assuming the default font size of the browser is 16px, 100rem = 100 * 16px = 1600px) width width Inside the parent element of <>,

attribute of the display: grid element is 20rem / 2 = 10REM, that is, 10 * 16 = 160px. height .child <素> The border distance of the element will exceed the parent element in all cases. Correct or wrong? height

.child Error.

.container {
  display: inline;
  width: 1rem;
  height: 1rem;
  background-color: currentColor;
}

<div class="parent">
  <div class="child"></div>
</div>
<div class="parent-flex">
  <div class="child"></div>
</div>

display: flex Is the border folding in the elements of display: inline-flex and display: grid effective? display: inline-grid

, <<>, display: inline-flex and display: inline-grid, the border distance will be accumulated.

The position of pseudo elements is horizontal and vertical. Correct or wrong? display: flex display: inline-flex display: grid Correct. The browser will allocate all the space between the sub -element and the parent element. display: inline-grid

.parent {
  display: block;
}

.parent-flex {
  display: flex;
}

<初> is

The min-width calculation value of the element is

.parent {
  display: inline-grid;
}

.parent::before {
  content: "";
  display: inline;  
}

.parent::after {
  content: "";
  display: flex;
}

<div class="parent">
  <div class="child"></div>
</div>

, min-width, auto, .child or min-width values ​​are defined for elements, then the auto calculation value of its sub -element is 0.

How do we use <属> attributes to replace block attributes? inline inline-block table We should define table-* attributes for <元> element. min-width

. Correct or wrong? gap margin

.parent { 
  display: grid; 
  width: 100rem; 
  height: 20rem; 
}

value of the .parent attribute to gap alternative value.

Why is the calculation value of display attributes of <素> element? block

<div class="parent">
  <div class="child"></div>
</div>

Elements with <<> or absolute will be removed from the normal document stream. Therefore, the parent element cannot see it. This is why the calculation value of the <性> attribute is 0. fixed

In the following example, what is the role of isolation attributes?

:is(#container, .content, main) {
  color: red;
}

.container {
  color: red;
}

:where(#container) {
  color: blue;
}

We should remember that when the z-index attribute is used, what stack the browser uses.

By default, the roots stacking context is html element. This is why the pseudo element is behind the isolation: isolate element without <情况>. .parent

elements. Therefore, the pseudo element is displayed behind the text, but in front of the isolation element. .child .parent What is the location of the pseudo element?

.container {
  display: inline;
  width: 1rem;
  height: 1rem;
  background-color: currentColor;
}

place-items: center After the application <<> and

, position: absolute, bottom: 0 and top attributes is higher than right property. bottom left <性> What is the calculation value of the attribute? place-items

<性> Priority of attributes is higher than width attributes, but its values ​​must also be within the range of

<div class="parent">
  <div class="child"></div>
</div>
<div class="parent-flex">
  <div class="child"></div>
</div>

flex-basis <性> What is the calculation value of the attribute? width min-width max-width When using CSS custom attributes, we should define all the abbreviated parts. If we don't do this, the browser cannot be used.

This happened in our example. padding The abbreviation requires 4 values, but only 3 developers are defined. The browser cannot be set up. Therefore, the calculation value is 0.

.parent {
  display: block;
}

.parent-flex {
  display: flex;
}

attribute of the <素> element?

padding CSS custom attributes will from the same custom attribute inheritance values ​​defined by parent elements. If the custom attribute is omitted, the browser will use the return value.

In our example, the p attribute is omitted from the parent elements. Therefore, the browser uses the refund value, that is, the background-color keyword, the keyword from the

.parent {
  display: inline-grid;
}

.parent::before {
  content: "";
  display: inline;  
}

.parent::after {
  content: "";
  display: flex;
}

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