Same height columns

HTML

<div class="same-height-columns">
    <!-- Column -->
    <div class="same-height-columns__column">
        <!-- Cover -->
        ...

        <!-- Content -->
        <div class="same-height-columns__content">...</div>

        <!-- Button sticks to the bottom -->
        ...
    </div>

    <!-- Repeat with other columns -->
    ...
</div>

CSS

.same-height-columns {
    display: flex;
}

.same-height-columns__column {
    flex: 1;
    /* Space between columns */
    margin: 0 8px;

    /* Layout each column */
    display: flex;
    flex-direction: column;
}

.same-height-columns__content {
    /* Take available height */
    flex: 1;
}