Classes, IDs, Display, Background Images

CSS Two

class Attribute

  • The class attribute lets us add one or more CSS classes to an element
  • Multiple elements may all use the same class saving you the need to write the same CSS rules multiple times
  • If multiple classes that contain competing CSS declarations are applied to an element, the class lower in the sheet takes precedence 
  • You can give multiple classes to one element, just separate the names with a space
  • To select classes in CSS, use a period before the class name
<p class="hero-text">
  Content content content.
</p>
<p class="hero-text red">
  More content.
</p>
.hero-text {
  font-size: 25px;
}

.red {
  color: red;
}

id Attribute

  • The id attribute can also be used to apply CSS styles to elements
  • ids differ from classes in that they should be used only once in a document
  • ids supersede class meaning that for an element with both an id and a class, the styles assigned to the id will always beat out class styles
<button class="form-btn" id="submit">Submit</button>
#submit {
  background-color: green;
}

.form-btn {
  background-color: white;
  border: 3px solid blue;
}

button {
  padding: 10px 20px;
  border: none;
  background-color: blue;
}

CSS Specificity

When an element has conflicting styles added to it, CSS specificity determines which style is used.

 

It works like a point system. The highest score styling block is applied.

Selecting the element: 1 point

Selecting the class: 10 points

Selecting the id: 100 points

Inline Styling: 1000 points

<div class="example" id="test"></div>

HTML

CSS

#test {
    height: 100px;
    width: 100px;
    background-color: cyan;
}

.example {
    height: 100px;
    width: 100px;
    background-color: blanchedalmond
}

Display Properties

Specifies the display behavior of an element

block - Stacks vertically and takes full width available, unless otherwise specified. Can change height and width.

inline - allows horizontal stacking. Size is only what it needs for its content. Can't change height or width.

inline-block - allows horizontal stacking. Can change height and width.

Background Images

  • background-image adds an image to the background of the element. Note that the size of the image can make this tricky.
  • background-position moves the image from its original place
  • background-repeat helps control what happens if the background image is too small. The default is to repeat horizontally and vertically, but other options include no-repeat, space, and round
  • background-size helps control the size of the image being used.
  • background-attachment helps control how the background moves when scrolling. Options include fixed, local and scroll.
div {
  width: 100vw;
  height: 200px;
  background-image: url(“https://image.com/cat”);
  background-position: center;
  background-repeat: no-repeat;
  background-size: contain;
  background-attachment: fixed;
}

Day 3: CSS Two

By Devmountain

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Day 3: CSS Two

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