CSS Tips: Flexbox, Shadows, Variables

1. Introduction to CSS

Cascading Style Sheets (CSS), the language used to mark up HTML code and give it a visual style, is one of the most effective ways to increase the attractiveness of a website. It can also lead to increased user engagement, retention, and satisfaction. In fact, there are whole career fields dedicated to the improvement of user experiences, known as User Interface (UI) design and User Experience (UX) design.

Some web developers are familiar with the common CSS properties, such as element sizing, fonts, and colors, but are not as well versed in less-used properties and values such as flexbox, clip-path, and transform. This article will provide some insight into the less-used and unique CSS properties.

2. CSS Variables

The first topic today is CSS variables. Variables are not often used by smaller developers. CSS variables allow you to give your website a well-defined structure, where you can easily reuse CSS properties throughout the project.

You can use variables to define things, such as color palettes. Then, you can use these colors for backgrounds anywhere else in the HTML. You can expand this and define variables for primary-text, quoted-text, etc. You can also use variables to define spacing (e.g. 32px or 2rem), which you can then apply to margins, padding, font sizes, and more.

For example, here are some variables defined at the root of the website, which allows for any subsequent CSS rules to use those variables:

:root {
    --primary-color: black;
    --secondary-color: white;
}

body {
    background-color: var(--primary-color);
    color: var(--secondary-color);
}

3. CSS Box Shadows

Box shadows were once my mortal enemy. No matter how hard I tried, I just couldn't get them to work how I wanted. Because of this, my favorite discovery has been CSSMatic's box shadow generator. It provides a tool to generate box shadows using their simple sliders. Surprisingly, this is the reason I learned how box shadows work! You can use the sliders and watch how the CSS code changes in the image that the tool displays. Through this, you should understand that the basic structure for box shadows is:

box-shadow: inset horizontal vertical blur spread color;

Now, let's look at some basic examples! You can copy and paste the following code into a site like CodePen or your own HTML files. Feel free to play around with the code, experiment, and learn.

Box Shadow #1

<div class="shadow-examples">
    <div class="box effect1">
        <h3>Effect 1</h3>
    </div>
</div>

.box h3 {
    text-align: center;
    position: relative;
    top: 80px;
}
.box {
    width: 70%;
    height: 200px;
    background: #fff;
    margin: 40px auto;
}
.effect1 {
    box-shadow: 0 10px 6px -6px #777;
}

Box Shadow #2

<div class="shadow-examples">
    <div class="box effect2">
        <h3>Effect 2</h3>
    </div>
</div>

.box h3 {
    text-align: center;
    position: relative;
    top: 80px;
}
.box {
    width: 70%;
    height: 200px;
    background: #fff;
    margin: 40px auto;
}
.effect2 {
    box-shadow: 10px 10px 5px -5px rgba(0, 0, 0, 0.75);
}

Try these box shadows out on your own and see how changing each shadow value works.

4. CSS Flex Box

Now, let's move on to the best part of this article: flex box. The flex box is by far my favorite new toy. I originally stumbled across this solution after looking for more efficient ways of centering content horizontally AND vertically. I had used other methods before, but flex box throws those out the window. The best part of it all is that flex box is dead simple.

Flex Box pertains to the parent div of any element. You want the parent to be the flex box and the children's behavior modified by the parent's attributes. It's easier to see this in action that explained, so let's see an example.

Flex Box

<div class="flex-examples">
    <div class="sm-box">
        <h3>1</h3>
    </div>
    <div class="sm-box">
        <h3>2</h3>
    </div>
</div>

.flex-examples {
    display: flex;
    flex-wrap: wrap;
    justify-content: flex-start;
    align-items: center;
    padding: 10px;
    background-color: #f2f2f2;
}
.sm-box {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 20%;
    height: 100px;
    background: #fff;
    margin: 40px 10px;
}

You may notice that we no longer need to use the top property for the h3 elements in our code. This is because we set the display box to be a flex container for the small boxes, AND we made the small boxes flex containers for their elements (the h3 tags). You can nest flex boxes to center content that is inside centered content.

For the example above, we designated the justify-content property to be flex-start so that the boxes stack from the left side of the screen. You can change this property to center to make the boxes appear in the center of the screen.

For an interactive example, check out this CodePen from LandonScropp. Resize the window with dice to see how they collapse and re-align.

5. Even More CSS

For more inspiration, you can visit CodePen, Dribbble, or UI Movement to browse the collections of amazing web designers.