Gain insights into designing mobile-responsive web layouts using Flexbox. Delve into Box Model basics, Flexbox containers, and item alignment, and apply your knowledge to create stunning, mobile-first websites.

CBCA - CSS with Flexbox (Intermediate)-01.jpg

In this course, you will get hands-on experience in designing mobile-responsive web layouts using Flexbox. You will start with the basics like the Box Model and the process of layouting.

You will then move on to advanced concepts such as Flexbox containers, and aligning individual Flexbox items. Near the end of the course, you will put everything you just learned into practice. You will work on a project that focuses on developing a mobile-first website where you’ll experiment with page layout, headers, footers, and a lot more.

By the end of this course, you will be able to use Flexbox in your own projects to create beautiful layouts.

Designing Web Layouts with CSS and Flexbox

# Step 1: Class annotations and basic Flexbox styling below 768px

Let's add a couple of classes to refer to the individual elements: 

```html
   <header>
     <h2 class="logo">Title</h2>
     <div class="hamburger-box"></div>
     <nav class="main-navigation">
       <ul class="flex-container">
         <li class="flex-item">Home</li>
         <li class="flex-item">About</li>
         <li class="flex-item">Contact</li>
       </ul>
     </nav>
   </header>
```

To eliminate non-uniform behavior, let's add a basic reset:

```css
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
```

We have learned about better resets than this one, but for the sake of the exercise, this simple reset will do the job.

We will use two Flexboxes: 

1. The `header` component itself is a Flexbox with the title on the left and one form of menu on the right.
2. The `.flex-container` item is also a Flexbox, spacing the three menu items evenly.

Let's add some basic styles below `768px`:

```css
header {
    display: flex;
    justify-content: space-between;
    margin: 20px;
    height: 30px;
}

.logo {
    height: 30px;
    background-color: lightgreen;
}

.main-navigation {
    height: 30px;
    background-color: lightsteelblue;
    display: none;
}


.hamburger-box {
    display: inline-block;
    width: 30px;
    min-width: 30px;
    height: 30px;
    background-color: aqua;
}
```

Notice that initially, the hamburger menu is displayed, but the main navigation is not. To make the width of the hamburger menu stay at `30px` width, we set both the `width` and the `min-width` of the hamburger menu to `30px`.

# Step 2: `flex-basis`

It is also worth adding `flex-basis` values at this stage. Let's calculate the `flex-basis` value to match the breakpoint widths: 

- At `768px` width, there are two `20px` margins on the left and the right. Therefore, there is `728px` space to distribute
- At a proportion of 2:1, we get `485px` for the title and `243px` for the inner menu.

```css
.logo {
    height: 30px;
    flex-basis: 485px;
    background-color: lightgreen;
}

.main-navigation {
    height: 30px;
    background-color: lightsteelblue;
    display: none;
    flex-basis: 243px;
}
```

# Step 3: Responsive breakpoint at `768px`

Let's add a breakpoint at `768px`:

```css
@media screen and (min-width: 768px) {

}
```

We will now hide the hamburger menu and show the main menu:

```css
@media screen and (min-width: 768px) {
    .hamburger-box {
        display: none;
    }

    .main-navigation {
        display: block;
    }
}
```

Notice the logo and the main navigation are already positioned properly because of the `justify-content` rule that applies for all screen sizes.

# Step 4: Set flex-grow

The `flex-basis` property of the logo was set to approximately a 2:1 ratio with respect to the `flex-basis` of the `.main-navigation` element. We will set the `flex-grow` properties of these elements to the same ratio respectively.

```css
@media screen and (min-width: 768px) {
    .hamburger-box {
        display: none;
    }

    .logo {
        flex-grow: 2;
    }

    .main-navigation {
        display: block;
        flex-grow: 1;
    }
}
```

# Step 5: Style the inner menu

Remove the unordered list and space the elements evenly.

```css
    .flex-container {
        display: flex;
        justify-content: space-evenly;
    }

    .flex-item {
        display: inline-block;
        list-style: none;
    }
```

The final solution looks as follows:

# Step 1: Class annotations and basic Flexbox styling below 768px

Let's add a couple of classes to refer to the individual elements: 

```html
   <header>
     <h2>Title</h2>
     <div></div>
     <nav>
       <ul>
         <li>Home</li>
         <li>About</li>
         <li>Contact</li>
       </ul>
     </nav>
   </header>
```

To eliminate non-uniform behavior, let's add a basic reset:

```css
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
```

We have learned about better resets than this one, but for the sake of the exercise, this simple reset will do the job.

We will use two Flexboxes: 

1. The `header` component itself is a Flexbox with the title on the left and one form of menu on the right.
2. The `.flex-container` item is also a Flexbox, spacing the three menu items evenly.

Let's add some basic styles below `768px`:

```css
header {
    display: flex;
    justify-content: space-between;
    margin: 20px;
    height: 30px;
}

.logo {
    height: 30px;
    background-color: lightgreen;
}

.main-navigation {
    height: 30px;
    background-color: lightsteelblue;
    display: none;
}


.hamburger-box {
    display: inline-block;
    width: 30px;
    min-width: 30px;
    height: 30px;
    background-color: aqua;
}
```

Notice that initially, the hamburger menu is displayed, but the main navigation is not. To make the width of the hamburger menu stay at `30px` width, we set both the `width` and the `min-width` of the hamburger menu to `30px`.

# Step 2: `flex-basis`

It is also worth adding `flex-basis` values at this stage. Let's calculate the `flex-basis` value to match the breakpoint widths: 

- At `768px` width, there are two `20px` margins on the left and the right. Therefore, there is `728px` space to distribute
- At a proportion of 2:1, we get `485px` for the title and `243px` for the inner menu.

```css
.logo {
    height: 30px;
    flex-basis: 485px;
    background-color: lightgreen;
}

.main-navigation {
    height: 30px;
    background-color: lightsteelblue;
    display: none;
    flex-basis: 243px;
}
```

# Step 3: Responsive breakpoint at `768px`

Let's add a breakpoint at `768px`:

```css
@media screen and (min-width: 768px) {

}
```

We will now hide the hamburger menu and show the main menu:

```css
@media screen and (min-width: 768px) {
    .hamburger-box {
        display: none;
    }

    .main-navigation {
        display: block;
    }
}
```

Notice the logo and the main navigation are already positioned properly because of the `justify-content` rule that applies for all screen sizes.

# Step 4: Set flex-grow

The `flex-basis` property of the logo was set to approximately a 2:1 ratio with respect to the `flex-basis` of the `.main-navigation` element. We will set the `flex-grow` properties of these elements to the same ratio respectively.

```css
@media screen and (min-width: 768px) {
    .hamburger-box {
        display: none;
    }

    .logo {
        flex-grow: 2;
    }

    .main-navigation {
        display: block;
        flex-grow: 1;
    }
}
```

# Step 5: Style the inner menu

Remove the unordered list and space the elements evenly.

```css
    .flex-container {
        display: flex;
        justify-content: space-evenly;
    }

    .flex-item {
        display: inline-block;
        list-style: none;
    }
```

The final solution looks as follows:

This lesson contains the solution to the flex-grow and flex-basis exercise in lesson.

Getting Started

Using Flexbox Containers

Aligning Individual Flexbox Items

Designing a Mobile-first Website Using Flexbox

Flexbox Conclusion and Next Steps

Flex-grow and Flex-basis Solution

Step 1: Class annotations and basic Flexbox styling below 768px