If you're going to use a flex container, keep in mind that all child elements will become flex items and stack vertically or horizontally, depending on flex-direction.
So, if we consider this code:
<div class="flex-container"><b>Lorem ipsum dolor sit amet</b> consectetur adipiscing elit. <span>Nunc at lectus vitae libero</span> pulvinar fringilla. <i>Nullam vel vestibulum orci.</i></div>
Although, the <b>, <span> and <i> elements are inline-level in a block formatting content...
.flex-container {
display: block;
flex-direction: row;
background-color: lightgreen;
}
span { color: red; }
<div class="flex-container"><b>Lorem ipsum dolor sit amet</b> consectetur adipiscing elit. <span>Nunc at lectus vitae libero</span> pulvinar fringilla. <i>Nullam vel vestibulum orci.</i></div>
ALL child elements are blockified in a flex formatting context...
.flex-container1 {
display: flex;
flex-direction: row;
background-color: lightgreen;
}
.flex-container2 {
display: flex;
flex-direction: column;
background-color: lightgreen;
}
span { color: red; }
<div class="flex-container1"><b>Lorem ipsum dolor sit amet</b> consectetur adipiscing elit. <span>Nunc at lectus vitae libero</span> pulvinar fringilla. <i>Nullam vel vestibulum orci.</i></div>
<hr>
<div class="flex-container2"><b>Lorem ipsum dolor sit amet</b> consectetur adipiscing elit. <span>Nunc at lectus vitae libero</span> pulvinar fringilla. <i>Nullam vel vestibulum orci.</i></div>
What you may want to do is wrap your text in its own block-level container within the flex container.
.flex-container1 {
display: flex;
flex-direction: row;
background-color: lightgreen;
}
.flex-container2 {
display: flex;
flex-direction: column;
background-color: lightgreen;
}
span {
color: red;
}
<div class="flex-container1">
<div>
<b>Lorem ipsum dolor sit amet</b> consectetur adipiscing elit. <span>Nunc at lectus vitae libero</span> pulvinar fringilla. <i>Nullam vel vestibulum orci.</i>
</div>
</div>
<hr>
<div class="flex-container2">
<div>
<b>Lorem ipsum dolor sit amet</b> consectetur adipiscing elit. <span>Nunc at lectus vitae libero</span> pulvinar fringilla. <i>Nullam vel vestibulum orci.</i>
</div>
</div>