Content helpers
Besides basic typography classes, helper classes are an extra set of additional predefined classes, that can be applied to different content or layout elements and components. Helper classes are custom additions mostly, written especially for current layout, except common BS helpers. Below is a summarized table with all available classes, descriptions and content type. Flex utilities are moved to a separate page and include various examples.
Borders
.border-0 Any element Use this class to remove all borders from an element
.border-[side]-0 Any element Use this class to remove specific borders. Available [side] options: left, right, top, bottom.
.border-width-0 Any element Sets border width to 0. Useful for inheriting other border properties
.border Any element Adds a border to an element with pre-defined BS's default width and color properties
.border-[size] Any element Adds the border to an element. Available [size] options: 1 - default border width (1px); 2 - double width (2px); 3 - tripple width (3px)
.border-[side]-[size] Any element Same as .border-[size], but for specific [side]: left, right, top, bottom
.border-[color] Any element Changes color of all element's borders. Supports all available color classes, including transparent option
.border-[side]-[color] Any element If you need to change color of some specific border, use this class combination. Options for [side]: left, right, top, bottom
.rounded Any element Rounds all borders. Default value is defined in $border-radius variable
.rounded-[side] Any element Rounds borders of specific [side]: top, bottom, left, right
.rounded-0 Any element Removes rounded corners from all borders
.rounded-[side]-0 Any element Removes rounded corners from specific [side]: top, bottom, left, right
.rounded-round Any element Adds 100px border radius to all borders
.rounded-[side]-round Any element Adds 100px border radius to specific [side]: top, bottom, left, right
.rounded-circle Any element Adds 50% border radius to all borders
Transformations
.rotate-[value] Any element Rotates element clockwise. Options for [value]: 45, 90, 180 degrees
.rotate-[value]-inverse Any element Same as .rotate-[value], but rotation is counterclockwise. Options for [value] are the same as well
.spinner Any element Adds infinite clockwise rotation
.spinner-reverse Any element Adds infinite counterclockwise rotation
Positioning
.position-[value] Any element Changes element's positiion. Available options for [value]: relative, static, absolute, fixed, sticky
.fixed-[top, bottom] Any element Position an element at the top (bottom) of the viewport, from edge to edge
.top-[0, auto] All except static Resets top property for fixed, absolute and relative opsitions
.bottom-[0, auto] All except static Resets bottom property for fixed, absolute and relative opsitions
.left-[0, auto] All except static Resets left property for fixed, absolute and relative opsitions
.right-[0, auto] All except static Resets right property for fixed, absolute and relative opsitions
Alignment
.float-[side] Any element Element floating. Options for [side]: left, right sides
.float-[breakpoint]-[side] Any element Responsive variations of element floating. Options for [breakpoint]: sm, md, lg, xlg screen sizes
.float-none Any element Removes floating
.clearfix Any element Easily clear floats by adding .clearfix to the element
.text-[side] Inline element, text Element alignment. Options for [side]: left, center, right sides
.text-[breakpoint]-[side] Inline element, text Responsive variations of element alignment. Options for [breakpoint]: sm, md, lg, xlg screen sizes
.align-[value] Inline element, table Vertical alignment. Options for [value]: baseline, top, middle, bottom, text-top and text-bottom
Images
.img-fluid Images only Applies max-width: 100%; and height: auto; to the image so that it scales nicely to the parent element
.img-thumbnail Images only Adds grey frame with white background color
Sizing
.wmin-[size] Any element Sets a minimum width of the element in pixels. Available options for [size]: 200, 250, 300, 350, 400, 450, 500, 550, 600 pixels
.wmin-[breakpoint]-[size] Any element Responsive variations of width utilities. Options for [breakpoint]: sm, md, lg, xlg screen sizes
.w-[25, 50, 75, 100] Any element Sets a width of the element in percents
.w-auto Any element Sets the width of an element to auto (width reset)
.w-[breakpoint]-auto Any element Responsive variations of width reset utility. Options for [breakpoint]: sm, md, lg, xlg screen sizes
.h-[25, 50, 75, 100] Any element Sets a height of the element in percents
.h-auto Any element Sets the height of an element to auto (height reset)
Visibility
.overflow-[value] Containers Content overflow utility. Available options for [value]: hidden - hides content, visible - shows content, auto - makes content scrollable
.visible Containers Makes the element invisible for the user, but visible for screen readers
.invisible Containers Can be used to toggle only the visibility of an element, meaning its display is not modified and the element can still affect the flow of the document
.text-hide Text only Helps replace an element's text content with a background image
.sr-only Any element Hides an element to all devices except screen readers
Display
.d-block Any element Displays an element as a block element
.d-[breakpoint]-block Any element Responsive variations of d-block utility. Options for [breakpoint]: sm, md, lg, xlg screen sizes
.d-inline-block Any element Displays an element as an inline-level block container
.d-[breakpoint]-inline-block Any element Responsive variations of d-inline-block utility. Options for [breakpoint]: sm, md, lg, xlg screen sizes
.d-inline Any element Displays an element as an inline container
.d-[breakpoint]-inline Any element Responsive variations of d-inline utility. Options for [breakpoint]: sm, md, lg, xlg screen sizes
.d-table Any element Displays an element as a table element
.d-[breakpoint]-table Any element Responsive variations of d-table utility. Options for [breakpoint]: sm, md, lg, xlg screen sizes
.d-table-cell Any element Displays an element as a table cell element
.d-[breakpoint]-table-cell Any element Responsive variations of d-table-cell utility. Options for [breakpoint]: sm, md, lg, xlg screen sizes
.d-flex Any element Displays an element as a block-level flex container
.d-[breakpoint]-flex Any element Responsive variations of d-flex utility. Options for [breakpoint]: sm, md, lg, xlg screen sizes
.d-inline-flex Any element Displays an element as an inline-level flex container
.d-[breakpoint]-inline-flex Any element Responsive variations of d-inline-flex utility. Options for [breakpoint]: sm, md, lg, xlg screen sizes
.d-none Any element Hides the element (has no effect on layout)
.d-[breakpoint]-none Any element Responsive variations of d-none utility. Options for [breakpoint]: sm, md, lg, xlg screen sizes
Spacing
.m-[size] Any element Adds margin property to all sides. Available [size] are: 0, 1 ~ 5px, 2 ~ 10px, 3 ~ 20px, 4 ~ 30px, 5 ~ 40px, auto
.m-[breakpoint]-[size] Any element Responsive variations of .m-[size] utility. Options for [breakpoint]: sm, md, lg, xlg screen sizes
.m[l,r,t,b,x,y]-[size] Any element Adds margin property to the specific side: l - left, r - right, t - top, b - bottom, x - horizontal, y - vertical. Options for the size are the same
.m[l,r,t,b]-[breakpoint]-[size] Any element Same as for .m-[breakpoint]-[size], except x and y options
.p-[size] Any element Adds padding property to all sides. Available [size] are: 0, 1 ~ 5px, 2 ~ 10px, 3 ~ 20px, 4 ~ 30px, 5 ~ 40px, auto
.p-[breakpoint]-[size] Any element Responsive variations of .p-[size] utility. Options for [breakpoint]: sm, md, lg, xlg screen sizes
.p[l,r,t,b,x,y]-[size] Any element Adds padding property to the specific side: l - left, r - right, t - top, b - bottom, x - horizontal, y - vertical. Options for the size are the same
.p[l,r,t,b]-[breakpoint]-[size] Any element Same as for .p-[breakpoint]-[size], except x and y options
.ml-2 Inline elements Adds extra left margin to the element (mostly for icons and badges)
.mr-2 Inline elements Adds extra right margin to the element (mostly for icons and badges)
Text
.font-size-[value] Text Sets/overrides font size. Available [value] options: base ~ 13px, xs ~ 11px; sm - 12px, lg ~ 14px
.line-height-[value] Text Makes it 20px despite the font size. Available [value] options: base, xs; sm, lg
Misc
.cursor-[value] Any element Changes cursor style. Available [value] options: move, pointer and default styles
.shadow-0 Any element Removes shadow from element
[data-fouc] jQuery plugins This is an attribute that partially helps to fix FOUC issue. It sets opacity to 0 and other properties to match styled component size. So that you won't see unstyled content flashing when plugin gets initialized.
Enable flex behaviors
Apply display utilities to create a flexbox container and transform direct children elements into flex items. Flex containers and items are able to be modified further with additional flex properties. The .d-flex class makes the flex container a block-level element. The .d-inline-flex class makes the flex container an atomic inline-level element. Please note: an anonymous flex item that contains only white space is not rendered, as if it were designated display: none. Also clear and vertical-align properties have no effect on flex items, and float causes the display property of the element to compute to block.

Flexbox container

I'm a flexbox container!

Inline flexbox container

I'm an inline flexbox container!
Display classes
.d-flex Displays an element as a block-level flex container
.d-[breakpoint]-flex Responsive variations of .d-flex class. Options for [breakpoint]: sm, md, lg, lg screen sizes
.d-inline-flex Displays an element as an inline-level flex container
.d-[breakpoint]-inline-flex Responsive variations of .d-inline-flex class. Options for [breakpoint]: sm, md, lg, lg screen sizes
Flex direction

Set the direction of flex items in a flex container with direction utilities. In most cases you can omit the horizontal class here as the browser default is row. However, you may encounter situations where you needed to explicitly set this value (like responsive layouts). Use .flex-row to set a horizontal direction (the browser default), or .flex-row-reverse to start the horizontal direction from the opposite side. Use .flex-column to set a vertical direction, or .flex-column-reverse to start the vertical direction from the opposite side.

Row direction

Flex item 1
Flex item 2
Flex item 3
Flex item 4

Reverse row direction

Flex item 1
Flex item 2
Flex item 3
Flex item 4

Column direction

Flex item 1
Flex item 2
Flex item 3
Flex item 4

Reverse column direction

Flex item 1
Flex item 2
Flex item 3
Flex item 4
Flex row classes
.flex-row Default value. The flexible items are displayed horizontally, as a row
.flex-[breakpoint]-row Responsive variations of .flex-row class. Options for [breakpoint]: sm, md, lg, lg screen sizes
.flex-row-reverse Same as row, but in reverse order
.flex-[breakpoint]-row-reverse Responsive variations of .flex-row-reverse class. Options for [breakpoint]: sm, md, lg, lg screen sizes
Flex column classes
.flex-column The flexible items are displayed vertically, as a column
.flex-[breakpoint]-column Responsive variations of .flex-column class. Options for [breakpoint]: sm, md, lg, lg screen sizes
.flex-column-reverse Same as column, but in reverse order
.flex-[breakpoint]-column-reverse Responsive variations of .flex-column-reverse class. Options for [breakpoint]: sm, md, lg, lg screen sizes
Justify content
Use justify-content utilities on flexbox containers to change the alignment of flex items on the main axis (the x-axis to start, y-axis if flex-direction: column). Choose from start (browser default), end, center, between, or around values. The alignment is done after the lengths and auto margins are applied, meaning that, if in a Flexbox layout there is at least one flexible element, with flex-grow different from 0, it will have no effect as there won't be any available space.

Beginning (start) of the container

Flex item
Flex item
Flex item

Center of the container

Flex item
Flex item
Flex item

End of the container

Flex item
Flex item
Flex item

With space between the lines

Flex item
Flex item
Flex item

With space before, between, and after the lines

Flex item
Flex item
Flex item
Justify content classes
.justify-content-[value] Aligns the flex container's items when the items don't use all available space on the main-axis (horizontally). Available options for [value]: start (browser default), end, center, between, or around.
.justify-content-[breakpoint]-[value] Responsive variations of .justify-content-[value] classes. Options for [breakpoint]: sm, md, lg, xl screen sizes
Align items
Use align-items utilities on flexbox containers to change the alignment of flex items on the cross axis (the y-axis to start, x-axis if flex-direction: column). Choose from start, end, center, baseline, or stretch (browser default). Basically it works like justify-content, but in the perpendicular direction. Tip: use the align-self property of each item to override the align-items property.

Beginning (start) of the container

Flex item
Flex item
Flex item

Center of the container

Flex item
Flex item
Flex item

End of the container

Flex item
Flex item
Flex item

WBaseline of the container

Flex item
Flex item
Flex item

Fit the container

Flex item
Flex item
Flex item
Align items classes
.align-items-[value] Alignment of items inside flex container. Options for [value]: start, end, center, baseline, or stretch (browser default).
.align-items-[breakpoint]-[value] Responsive variations of .align-items-[value] classes. Options for [breakpoint]: sm, md, lg, xl screen sizes
Align self
Use align-self utilities on flexbox items to individually change their alignment on the cross axis (the y-axis to start, x-axis if flex-direction: column). Choose from the same options as align-items: start, end, center, baseline, or stretch (browser default). The property doesn't apply to block-level boxes, or to table cells.

Beginning (start) of the container

Flex item
Aligned flex item
Flex item

Center of the container

Flex item
Aligned flex item
Flex item

End of the container

Flex item
Aligned flex item
Flex item

Baseline of the container

Flex item
Aligned flex item
Flex item

Fit the container

Flex item
Aligned flex item
Flex item
Align self classes
.align-self-[value] Alignment of the selected item inside flex container. Options for [value]: start, end, center, baseline, or stretch (browser default).
.align-self-[breakpoint]-[value] Responsive variations of .align-self-[value] classes. Options for [breakpoint]: sm, md, lg, xl screen sizes.
Auto margins
Flexbox can do some pretty awesome things when you mix flex alignments with auto margins. Shown below are three examples of controlling flex items via auto margins: default (no auto margin), pushing two items to the right (.mr-auto), and pushing two items to the left (.ml-auto). Unfortunately, IE10 and IE11 do not properly support auto margins on flex items whose parent has a non-default justify-content value.

Right auto margin

Flex item 1
Flex item 2
Flex item 3

Left auto margin

Flex item 1
Flex item 2
Flex item 3

Bottom auto margin

Flex item 1
Flex item 2
Flex item 3

Top auto margin

Flex item 1
Flex item 2
Flex item 3
Auto margin classes
.m[t,b,l,r]-auto Pushes flex items to specified side, where "l" is left, "r" is right, "t" is top and "b" is bottom.
.m[t,b,l,r]-[breakpoint]-auto Responsive variations of .m[t,b,l,r]-auto classes. Options for [breakpoint]: sm, md, lg, xl screen sizes
Flex wrap
The flex-wrap classes specify whether flex items are forced into a single line or can be wrapped onto multiple lines. If wrapping is allowed, this property also enables you to control the direction in which lines are stacked. Note: if the elements are not flexible items, the flex-wrap property has no effect. Supports 2 directions: default and reversed.

No wrap

Flex item
Flex item
Flex item
Flex item

Wrap - default direction

Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item

Wrap - reversed direction

Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex wrap classes
.flex-nowrap The flex items are laid out in a single line - may cause the flex container to overflow
.flex-[breakpoint]-nowrap Responsive variations of .flex-nowrap class. Options for [breakpoint]: sm, md, lg, xl screen sizes
.flex-wrap The flex items break into multiple lines
.flex-[breakpoint]-wrap Responsive variations of .flex-wrap class. Options for [breakpoint]: sm, md, lg, xl screen sizes
.flex-wrap-reverse Behaves the same as .flex-wrap, but in reverse order
.flex-[breakpoint]-wrap-reverse Responsive variations of .flex-wrap-reverse class. Options for [breakpoint]: sm, md, lg, xl screen sizes
Flex order
Change the visual order of specific flex items with a handful of order utilities. We only provide options for making an item first or last, as well as a reset to use the DOM order. As order takes any integer value (e.g., 5), add custom CSS for any additional values needed. Elements with the same order value are laid out in the order in which they appear in the source code. Note: If the element is not a flexible item, the order property has no effect.

Default order

Flex item 1
Flex item 2
Flex item 3

Custom order

Flex item 1
Flex item 2
Flex item 3

Default order

Flex item 1
Flex item 2
Flex item 3

Custom order

Flex item 1
Flex item 2
Flex item 3
Flex order classes
.order-[value] Specify the order used to lay out flex items in their flex container. Values for [value]: 1, 2, ... 12.
.order-[breakpoint]-[value] Responsive variations of .order-[value] classes. Options for [breakpoint]: sm, md, lg, xl screen sizes
Align content
Use align-content utilities on flexbox containers to align flex items together on the cross axis. Choose from start (browser default), end, center, between, around, or stretch. To demonstrate these utilities, we’ve enforced flex-wrap: wrap and increased the number of flex items. Note: this property has no effect on single rows of flex items.

Start of the flex container

Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item

End of the flex container

Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item

Center of the flex container

Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item

Evenly in the flex container

Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item

Evenly with half-size spaces on either end

Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item

Stretch to take up the remaining space

Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Flex item
Align content classes
.align-content-[value] Similar to align-items, but instead of aligning flex items, it aligns flex lines. Options for [value] are similar to .justify-content-[value] classes
.align-content-[breakpoint]-[value] Responsive variations of .align-content-[value] classes. Options for [breakpoint]: sm, md, lg, xl screen sizes