.container-example {
    display: flex;
    align-items: center;
    justify-content: center;
}
DOCUMENTATION FROM: https://developer.mozilla.org/en-US/docs/Web/CSS/display
START POINT proterties ARE display, flex, flex-flow, place-items, place-content, place-self, gap, box-sizing:
display       — values flex, grid
flex          — shorthand for flex-grow, flex-shrink, and flex-basis.
flex-flow     — shorthand property for flex-direction and flex-wrap properties.
place-items   — shorthand property sets the align-items and justify-items properties.
place-content — shorthand for align-content and justify-content. 
place-self    — shorthand property sets both the align-self and justify-self properties. 
gap           — shorthand for row-gap and column-gap.
box-sizing    — values 
                «content-box» and 
                «border-box» (when width = border + padding + width, and height = border + padding + height )
inline-block  — It is equivalent to `inline flow-root`.
inline-flex   — It is equivalent to `inline flex`.
align-content — property sets the distribution of space between and around content 
                items along a flexbox's cross-axis or a grid's block axis.
align-items
align-self
flex
flex-wrap
flex-direction
justify-content
justify-items
justify-self
place-content
place-items   — shorthand property sets the align-items and justify-items properties, respectively. 
                If the second value is not set, the first value is also used for it.
place-self