Bootstrap 4类列表 v4.1.0

Complete list of all Bootstrap 4 classes with description, examples, and links to documentation.

Click each column header to sort alphabetically.

Class Name	Preview	Description	Category
.align-*		A set of utility classes that are equivelant to writing the css property `vertical-align:middle;` You can use this on inline and table cell elements. `.align-(baseline, top, middle, bottom)`	Utility
.align-content-*		Added to the parent flexbox container to determing how the elements are aligned horizontally. `.align-content-(start (browser default), end, center, between, around, or stretch)`	Utility
.align-items-*		Class added to flexbox child items to specify if it should align towards the top or bottom of the container (start, end)	Utility
.align-self-*		Used on flexbox items to align them vertically in relation to the parent container. If columns are used the items will align verticall. (start, end, center, baseline, or stretch (browser default)	Utility
.align-text-*		A set of utility classes that are equivelant to writing the css property `vertical-align:text-bottom;` You can use this on inline and table cell elements. `.align-text-(top, bottom)`	Utility
.badge-*		Used for labels and counters in applications `.badge-(light, dark primary, secondary, transparent, white, warning, success, info, danger)`	Badge
.bg-*		Background color utility classes: `.bg-(light, dark primary, secondary, transparent, white, warning, success, info, danger)`	Utilities
.border-*		A versatile border utility class that lets you add/remove borders on a side or change a border color. `.border-(light, dark primary, secondary, transparent, white, warning, success, info, danger, 0, top-0, right-0, bottom-0, left-0, top, right, bottom, left)`	Utility
.btn-outline-*		A button variation to have outlined buttons instead of a solid background. `.btn-outline-(light, dark primary, secondary, transparent, white, warning, success, info, danger)`	Buttons
.carousel-control-*		When you have an image carousel with pagination you will use this class on the previous and next anchor links. `.carousel-control-(prev, next)`	Carousel
.carousel-fade	n/a	Animates the slide transition with a crossfade instead of a slide	Utility
.col		Flexbox items are automatically equal width so this class is used when you want your columns to be equal width and then go 100% on the xs breakpoint.	Grid
.col-*		This class is used for grid columns to determin the column width and the breakpoint you would like it to be active. The classes work from the breakpoint you set and everything larger. `.col-(sm, md, lg, xl)-(1-12)`	Grid
.custom-range		Changes the default styling of a form input range	Forms
.d-flex	n/a	Sets the element to have have the style property `display:flex;`	Utility
.d-none	n/a	Sets the element to have have the style property `display:none;`	Utility
.d--	n/a	A responsive display utility class that lets you specify when a display property is applied to the element. `.d-(sm, md, lg, xl)-(none, inline, inline-block, block, table, table-cell, table-row, flex, inline-flex )`	Utility
.d-print-*	n/a	Changes the display of elements when you print the document. `.d-print-(flex, inline-flex, table, table-cell, table-row)`	Utility
.fixed-*	n/a	This class makes an element fixed to the top/bottom of the browser window. Here is what the CSS ruleset looks like. `.fixed-bottom {position: fixed;right: 0;bottom: 0;left: 0;z-index: 1030;}`	Utility
.flex---*	n/a	Change the flexbox items layout, alignment, or size. `.flex-(sm, md, lg, xl)-(row, row-reverse, column)`	Utility
.flex-fill-*	n/a	Add to all sibling elements you would like to force into equal widths and fill all available horizontal space. `.flex-fill-(sm, md, lg, xl)`	Utility
.flex-(grow\|shrink)-*	n/a	Forces an element to grow or shrink to use more or less of the space available `.flex-(grow, shrink)-(0, 1)`	Utility
.float--	n/a	Responsive utility to float an element. `.float-(sm, md, lg, xl)-(none, left, right)`	Utility
.form-control-plaintext		Use the `.form-control-plaintext` class to remove the default form field styling and preserve the correct margin and padding.	Forms
.form-row		Works similar to a grid `.row` but is more compact to make the form look more uniform	Forms
.h-*		Height utility class that makes the element a percentage height of its parent element. `h-(25,50,78,100, auto)`	Utility
.invalid-feedback		This class can be added with server side form validation to add a feedback message to an invalid field	Forms
.is-*	n/a	If you do server side form validation you can use this class to set feedback colors on inputs or error message. `.is-(valid, invalid)`	Forms
.justify-content--		Class specifies where the flex items will be positioned inside the container. `.justify-content-(sm, md, lg, xl)-(start, end, center, between, around)`	Utility
.m--*	n/a	Applies margin to an element using responsive breakpoints {property}{sides}-{breakpoint}-{size} `m(t,b,r,l,x,y)-(sm, md, lg, xl)-(0, 1, 2, 3, 4, 5)`	Utility
.p--*	n/a	Applies padding to an element using responsive breakpoints {property}{sides}-{breakpoint}-{size} `p(t,b,r,l,x,y)-(sm, md, lg, xl)-(0, 1, 2, 3, 4, 5)`	Utility
.progress-bar-animated		When this class is added to a progressbar the progress will be animated using css3 animations	Progress
.nav-fill		Makes all nav items use all available horizontal space. Nav items are different widths baded on their content.	Navs
.nav-justified		Makes all nav items equal width and use all available horizontal space.	Navs
.navbar-collapse	n/a	The nav links that are collapsed and shown when toggled on mobile widths.	Navbar
.navbar-expand-*	n/a	Since the navbar is displayed collapse on mobile first, this class specifies what breakpoint you want the navbar to not be collapsed	Navbar
.navbar-text	n/a	Vertically centers text inside a navbar	Navbar
.navbar-toggler-icon		The cheeseburger navigation icon is set using an svg background image of three horizontal lines	Navbar
.no-gutters	n/a	Removes the negative margin on the `.row` and padding from the child columns. Helpful when you want an image to expand to the edges of the browser without padding on the left and right edges.	Grid
.order--		This class is used to control how the elements are ordered on the page regardless of their order in the source code. So you can rearrange your layout as needed.	Grid
.rounded-*		The .img-rounded class was renamed to this and is primarily used with images. However, the class just adds a border radius so you could use this on other elements that you would like a radius applied.	Images
.visible	n/a	Hides the visibility of an element but does not change their display property.	Utility
.w-*		Width utility class that makes the element a percentage width of its parent element. `w-(25,50,78,100, auto)`	Utility
.was-validated		This class is set by Bootstrap's javascript to apply sub class validation styles to the form inputs.	Forms
.alert-heading		This class is added to headings inside alerts. It applies color:inherit so the colors match.	Alerts
.blockquote		Add to blockquote elements to apply the proper spacing and bottom margin to seperate it from other text.	Blockquotes
.blockquote-footer		Wrapping class for citation text underneath a blockquote. Used to lighten the text color.	Blockquotes
.btn-group-lg		Increases the default button group size	Button Group
.btn-group-sm		Decreases the default button group size	Button Group
.btn-group-toggle		This class replaces an input checkbox with a custom style that is toggable on click	Button Group
.btn-lg		Increases the default button size	Buttons
.btn-outline-*		Transparent background with colored text and border (danger\|info\|primary\|secondary\|success\|warning)	Buttons
.card		The class added to the div that wraps each individual card	Cards
.card-body		This class is added to the first child div inside the div.card parent	Cards
.card-columns		The .card-columns class is added to the wrapping div of of masonry-like collection of cards	Cards
.card-*		First add .card-inverse and then add one of the contextual background colors (danger\|info\|primary\|secondary\|success\|warning)	Cards
.card-deck		Similar to columns Bootstrap card decks are equal height and width	Cards
.card-footer		Wrap class for a card footer content area	Cards
.card-group		The parent wrapping class around a group of cards. Groups are similar to decks but they have no margin between each card.	Cards
.card-header		Wrap class for a card header content area	Cards
.card-header-pills		Class added in combination with .nav-pills to add pill navigation to a card header	Cards
.card-header-tabs		Class added in combination with .nav-pills to add tab navigation to a card header	Cards
.card-img		Add this class to the image you would like to have as a card background image. Used with creating cards with image overlays.	Cards
.card-img-bottom		Similar to a card footer you can cap the bottom of a card with an image	Cards
.card-img-overlay		Wrapper class used to create a card that has a background image overlay	Cards
.card-img-top		Similar to a card header you can cap the top of a card with an image	Cards
.card-inverse		Inverts the default colors to use light text on a dark background color	Cards
.card-link		Adds spacing around links added inside cards	Cards
.card-subtitle		Class added to card subtitles that adjusts the default heading styles	Cards
.card-text		This class wraps the container around card text	Cards
.card-title		The class added to titles inside cards. It applies the proper spacing.	Cards
.carousel-item		The wrapper class applied to each individual carousel item	Carousel
.clearfix	n/a	Clears the floats of any child elements. Add this class to the parent element wrapping the floating elements.	Utility
.col-form-label		Class added to form labels to apply consistent padding and margins	Forms
.col-form-label-lg		Increases the font size and spacing of a form label	Forms
.col-form-label-sm		Decreases the font size and spacing of a form label	Forms
.col-xl-*	n/a	Set column width for anything greater than 1200px. Specify the column span by adding 1-12 at the end	Grid system
.custom-checkbox		Parent class that converts a default form checkbox into a custom HTML/CSS checkbox	Forms
.custom-control	n/a	Used on all custom form inputs and adds base styles like padding and display:inline	Forms
.custom-control-inline		Custom form checkboxes are set to be display:block. Use this class to make the checkbox inline	Forms
.custom-control-input	n/a	This class is added to the default input that is going to be replaced. It adds the following: position: absolute; z-index: -1; opacity: 0;	Forms
.custom-control-label		When creating a custom form checkbox, this class replaces the default checkbox with custom elements using :before and :after	Forms
.custom-file		Class added to a label of grouped elements to create a custom file upload input	Forms
.custom-file-control		Similar to the custom-control-indicator class this class is added to a div to build a custom file input using CSS :before and :after.	Forms
.custom-file-input	n/a	This class is added to the default input type="file" and hides it using CSS	Forms
.custom-file-label		When creating a custom form file browser, this class replaces the default file browser with custom elements using :after	Forms
.custom-radio		This class is added to the parent label tag along with .custom-control class to specify what kind of custom input it will be	Forms
.custom-select		Class added to a select tag to create a custom select menu	Forms
.custom-select-sm		Decreases the font size and padding on a custom select	Forms
.custom-select-lg		Increases the relative size of a custom form select	Forms
.d-*		Append the following to change the element display property (block, inline, inline-block)	Utility
.disabled		Add this class to anchor tags to disable the click functionality but still have them visible.	Buttons
.display-*		This set of classes increases the font size of headings in 4 stages. These classes are used for headings outside of the main content of the page like jumbotrons and page headers. Append (1-4) to the end to adjust size.	Typography
.dropdown-divider		Class adds a horizontal line between dropdown link items	Dropdowns
.dropdown-item		This class is added to each link item shown in a dropdown menu	Dropdowns
.dropdown-item-text	n/a	Removes the interactivity from a dropdown so it does not appear clickable	Dropdowns
.dropdown-toggle-split		Class added to the notched dropdown navigation. Great for providing additional actions but still having a primary action.	Dropdowns
.dropleft		Dropdown menu that opens left of the button	Dropdowns
.dropright		Dropdown menu that opens right of the button	Dropdowns
.dropup		Displays the dropdown menu above the button instead of below.	Dropdowns
.embed-responsive-*	n/a	Class used to adjust responsive embed aspect ratio. Append one of the following for the desired aspect ratio (21by9, 16by9, 4by3, 1by1)	Utility
.embed-responsive-item	n/a	By default responsive embeds apply to iframe, object, embed, and video tags. You can add .embed-responsive-item to any other element to have the same responsive styles applied	Utility
.figure-caption		Added to a figure figcaption element to apply font styling	Content
.figure-img		Classed added to images inside a figure to apply some margin	Content
.font-*		(italic, weight-bold, weight-light, weight-normal, monospace)	Utility
.form-check		The parent class of form checkboxes	Forms
.form-check-inline		Class used for a horizontal group of checkmarks or radio buttons	Forms
.form-check-input		This class is added to the input tag for checkboxes and radio buttons. Adds styles for positioning and margins.	Forms
.form-check-label		This class is added to checkbox and radio button labels	Forms
.form-control-file		The class added to input type="file" to apply font and spacing	Forms
.form-control-*		Apply this class to form elements to increase or decrease its size relative to the default sizing .form-control-(lg, sm)	Forms
.form-inline		Use this class to have a series of labels and form elements on a single horizontal row	Forms
.form-text		This class is used for help text alongside form elements. You can add .text-muted to make the text lighter in color	Forms
.has-*		The .has-(success, warning, danger) is added to the parent form element container to apply visual feedback to the user on form validation.	Forms
.img-fluid		This class is applied to images you would like to be responsive or fluid width across various screen sizes. This was .img-responsive in v3	Images
.input-group-*		This class lets you extend form controls by adding text or buttons to the left or right of the input. .input-group-(addon\|btn)	Input Group
.input-group-append		This class adds margin-left: -1px; to the input set to left of the group to compensate for the 1px border	Input Group
.input-group-prepend		This class adds margin-right: -1px; to the input set to right of the group to compensate for the 1px border	Input Group
.input-group-text		This class adds the background color and text styles to the text inside an input group	Forms
.jumbotron-fluid		A default jumbotron is not full width but adding this class removes the rounded corners and makes it extend to 100% of its parent	Jumbotron
.list-group-flush		When adding a list group to a card add this class to the list group to remove the border. Otherwise you will have a double border.	Cards
.list-group-item-action		Add this class to each anchor in a list-group to remove the default anchor text color	List Group
.list-inline		Change ul or ol list to be listed horizontally with a little margin between each li	Typography
.m*-#		Sometimes you need to add some margin or padding to element without writing a custom CSS selector. Set margin or padding, the side to apply the spacing, and lastly the size of the spacing (m,p)-(t\|r\|b\|l\|x\|y\|a)-(0,1,2,1.5,3)	Utility
.media-bottom		Add this class the div wrapping the media object image to align it to the bottom	Media Object
.media-left		Add this class the div wrapping the media object image to align it to the left	Media Object
.media-middle		Add this class the div wrapping the media object image to center it vertically	Media Object
.media-right		Add this class the div wrapping the media object image to align it to the right	Media Object
.nav-item		If your nav uses a list add this class to each list item for the proper spacing	Navs
.nav-link		Each anchor link inside your nav is given this class in order to have the proper styling	Navs
.nav-pills		Use this class along with .nav to make each nav link into a button	Navs
.navbar-light		Add this class to your navbar if you would like it to have a light background and dark text	Navbar
.navbar-toggler		The infamous cheeseburger icon to signify a navigation menu on mobile	Navbar
.offset--		Used to offset a grid column from its original position	Grid System
.p*-#		Sometimes you need to add some margin or padding to element without writing a custom CSS selector. Set margin or padding, the side to apply the spacing, and lastly the size of the spacing (m,p)-(t\|r\|b\|l\|x\|y\|a)-(0,1,2,1.5,3)	Utilities
.page-item		This class is added to each li inside the ul.pagination and floats the li's'	Pagination
.page-link		This class is added to each anchor link containing the numbers	Pagination
.pagination-sm		Decreases the font size and spacing of a pagination nav	Pagination
.pagination-lg		Increases the font size and spacing of a pagination nav	Pagination
.position-*	N/A	Not responsive, but a group of utility classes to add common position values. .position-(absolute, fixed, relative, static, sticky)	Utilities
.shadow-*		Adds a black CSS box shadow to an element. `.shadow-(none, sm, lg)`	Utility
.pos-f-t	n/a	Positions an element fixed to the top of the viewport and full width.	Utility
.sr-only	n/a	Hide element to all devices except screen readers	Utilities
.sr-only-focusable	n/a	Combine .sr-only with .sr-only-focusable to show the element again when it’s focused by a user using a keyboard	Utilities
.table-*		Adds a 1px stroke around the rows, columns, and table outline. You can also remove the borders entirely. `.table-(bordered, borderless)`	Tables
.table-*		Contextual classes of different color styles to provide user feedback (active\|danger\|info\|primary\|secondary\|success\|warning)	Tables
.table-hover		Adds a background color when you hover a table row	Tables
.table-reflow		The table header becomes the first column of the table to the left	Tables
.table-sm		Removes vertical padding between table rows so it does not take as much vertical space. Good for tables with a lot of rows.	Tables
.table-striped		Adds a light background color to every other table row for a striped effect	Tables
.text--		Aligns text left, right or center use choose breakpoint (xs\|sm\|md\|lg\|xl) then alignment (left, right, center)	Utilities
.thead-dark		The default table head styling of light background and dark text	Tables
.thead-light		Inverts the table head to have a dark background and light text	Tables
.alert		The .alert class adds base styling with padding and margin.	Alerts
.alert-*		Change the color of the alert to provide user feedback. (primary, secondary, success, danger, warning, info, light, dark)	Alerts
.alert-dismissible		Similar to a well it is a box with a border and padding. This class and a child element with a .close class lets the user close the alert.	Alerts
.alert-link		When you add links inside alert this class matches the font color to the parent alert class.	Alerts
.active		Tables contextual class to change row color	Tables
.bg-danger		Similar to the contextual text color classes, easily set the background of an element to any contextual class. Anchor components will darken on hover, just like the text classes.	Helper Classes
.bg-info		Similar to the contextual text color classes, easily set the background of an element to any contextual class. Anchor components will darken on hover, just like the text classes.	Helper Classes
.bg-primary		Similar to the contextual text color classes, easily set the background of an element to any contextual class. Anchor components will darken on hover, just like the text classes.	Helper Classes
.bg-success		Similar to the contextual text color classes, easily set the background of an element to any contextual class. Anchor components will darken on hover, just like the text classes.	Helper Classes
.bg-warning		Similar to the contextual text color classes, easily set the background of an element to any contextual class. Anchor components will darken on hover, just like the text classes.	Helper Classes
.breadcrumb		Indicate the current page's location within a navigational hierarchy.	Breadcrumbs
.btn		This class sets the spacing and size of the button.	Buttons
.btn-block		By default buttons are inline this class makes it block to span the full width of its parent.	Buttons
.btn-danger		Defaults to a red background button	Buttons
.btn-group		Smushes multiple buttons together to make a pill shape. Each button is separated by a vertical line.	Button groups
.btn-group-vertical		Make a set of buttons appear vertically stacked rather than horizontally.	Button groups
.btn-info		Button for information on a topic like terms and conditions. Default is light blue.	Buttons
.btn-link		Keeps the spacing set with the .btn class but removes the outer border.	Buttons
.btn-lg		Fancy larger or smaller buttons? Add .btn-lg, .btn-sm, or .btn-xs for additional sizes.	Buttons
.btn-primary		Use for the primary action in a set.	Buttons
.btn-sm		Fancy larger or smaller buttons? Add .btn-lg, .btn-sm, or .btn-xs for additional sizes.	Buttons
.btn-success		Defaults to a green background button with dark border.	Buttons
.btn-toolbar		Used to create a row of buttons similar pagination row	Button groups
.btn-warning		Defaults to a yellow background button with dark border.	Buttons
.carousel		parent carousel class making it position relative	Carousel
.carousel-caption		Caption for each slide item	Carousel
.carousel-indicators		parent classed added to an ordered list for the little circles showing what slide you are on	Carousel
.carousel-inner		The div wrapper that contains the carousel slide items	Carousel
.close		Use the generic close icon for dismissing content like modals and alerts.	Helper Classes
.col--		span 1-12 column. Extra small devices Phones ( < 768px), Small devices Tablets (≥768px), Medium devices Desktops (≥992px), Large devices Desktops (≥1200px). Column device Column numeric values can be 1-12.	Grid system
.col--pull-		Easily change the order of our built-in grid columns with .col--push- and .col--pull- modifier classes. Pull numeric values can be 0-12.	Grid system
.col--push-		Easily change the order of our built-in grid columns with .col--push- and .col--pull- modifier classes. Push numeric values can be 0-12.	Grid system
.collapse		hides content on hide and show component	Collapse
.collapsing		applied during transitions on hide and show component	Collapse
.container		Fixed width container with widths determined by screen sites. Equal margin on the left and right.	Grid system
.container-fluid		Spans the full width of the screen	Grid system
.dropdown		This class gives you the ability to add a dropdown to navbar, tabs, and pills so you can display a dropdown of additional navigation.	Dropdowns
.dropdown-header		Used to add headers inside the dropdown menu	Dropdown
.dropdown-menu		Adds the default styles for the dropdown menu container	Dropdown
.dropdown-toggle		This class is added to the button that will have the toggle action applied that will hide and show the dropdown menu	Dropdown
.embed-responsive		The default responsive iframe embed styles	Embed
.embed-responsive-16by9		Div wrapper class to make child iframe responsive	Embed
.embed-responsive-4by3		Div wrapper class to make child iframe responsive	Embed
.fade		To have your alerts use animation when closing, make sure they have the .fade and .in classes already applied to them.	Alerts
.form-control		Class added input, textarea, and select to make them 100% and responsive	Forms
.form-group		A div wrapper class that goes around a form input and label	Forms
.h1 - .h6		Apply heading styles to other elements. Make a paragraph look like an h1	Typography
.img-thumbnail		Adds rounded corners and an inset border to an image	Images
.info		Tables contextual class to change row color" target="_blank" href="https://getbootstrap.com/docs/4.1/content/tables/#contextual-classes	Tables
.initialism		Add .initialism to an abbreviation for a slightly smaller font-size.	Typography
.input-group		Wrapper class used to enhance an input and label group by adding a button in front or behind as help text	Input groups
.invisible		Make something invisible	Helper Classes
.jumbotron		A content section that is used to showcase important content. Commonly used on home pages and category pages.	Jumbotron
.lead		Increase the font size and line height of a paragraph. Good to use on the first paragraph of an article to improve readability.	Typography
.list-group		Wrapper ul class that contains li with borders	List group
.list-group-item		Class added to each li in a list-group	List group
.list-group-item-text		Class added to an anchor or p for a .list-group-item text under a heading	List group
.list-group-item-*		Change color of list group item by adding one of the following: default, warning, info, danger, primary	List group
.list-inline		Overrides a lists default style to be inline and block	Typography
.list-unstyled		Removes all bullet styling from a ul or ol list	Typography
.mark		For highlighting a run of text due to its relevance in another context, use the mark tag.	Typography
.media		Media components are image heading and description text items. Blog comments, portfolio projects, album covers, etc.	Media object
.media-body		The class added for the media description copy block	Media object
.modal		The parent wrapper class of modal content	Modal
.modal-backdrop		Added by the modal javascript to make the area around the modal clickable to hide the modal	Modal
.modal-body		The modal body content class : Header - Body - Footer	Modal
.modal-content		modal-content contains modal-body, modal-header, and modal-footer	Modal
.modal-dialog		The secondary wrapper class of the entire modal content	Modal
.modal-dialog-centered		Vertically and horizontally centers a modal dialog	Modal
.modal-footer		The footer of the modal that contains action buttons or help text	Modal
.modal-header		The header section of the modal that contains the title and close button	Modal
.modal-lg		Makes a modal wider	Modal
.modal-open		Javascript adds this class to the body tag to prevent scrolling with the modal is open	Modal
.modal-sm		Makes the modal not as wide	Modal
.modal-title		The title of the modal	Modal
.nav		nav base class added all types of navigation: tabs, pills, justified, disabled links	Navs
.nav-tabs		Class added to enable Bootstrap tabs	Tab
.navbar		Navigation header class	Navbar
.navbar-brand		Most navbars contain a logo or brand. This class is added to the anchor	Navbar
.navbar-nav		The wrapper class of the navigation elements excluding the brand	Navbar
.next		Used in the carousel control to identity the next control	Carousel
.pagination		The wrapper class that contains all of the page navigation	Pagination
.pre-scrollable		You may optionally add the .pre-scrollable class, which will set a max-height of 350px and provide a y-axis scrollbar.	Code
.progress		The parent class wrapper of a progress bar	Progress bars
.progress-bar		The class applied to the progress bar graphic that moves	Progress bars
.progress-bar-striped		Changes progress to a striped version	Progress bars
.row		used a parent wrapper of any vertical columns	Grid system
.small		Create lighter, secondary text in any heading with a generic tag or the .small class.	Typography
.sr-only		Hide an element to all devices except screen readers with .sr-only.	Helper Classes
.success		Tables contextual class to change row color	Tables
.tab-pane		Class added to the div that will act as a tab content area	Tab
.table		Adding this class to a HTML table applies the Bootstrap styles	Tables
.table-sm		Removes some padding from the table cells	Tables
.table-bordered		Adds borders to a table and its cells	Tables
.table-responsive-*		Makes a table responsive by cropping a wide table and makes it scrollable horizontally. .table-responsive or .table-responsive-(lg, md, sm, xl)	Tables
.text-capitalize		Capitalize the text or title case	Typography
.text-justify		Full justifys the text	Typography
.text-lowercase		Changes text to lowercase	Typography
.text-nowrap		Prevents the text from wrapping	Typography
.text-*		Changes text color to a contextual color or grayscale value `.text-(primary, secondary, success, danger, warning, info, light, dark, body, muted, white, black-50, white-50)`	Color
.text-uppercase		Makes text uppercase	Typography
.tooltip		This class is used by the tooltip javascript as the wrapper of the toolitp	Tooltip
.tooltip-inner		The wrapper class of tooltip text. This is generated by the Bootstrap javascript Some tooltip text!	Tooltip

Pixels to Rem Conversion Table

If you are working with a PSD file set in pixels you will often need to convert this to Rems. In Bootstrap 4 the default font size is 16px or 1 Rem

Pixels	Rems
Pixels	Rems
1	0.0625
2	0.125
3	0.1875
4	0.25
5	0.3125
6	0.375
7	0.4375
8	0.5
9	0.5625
10	0.625
11	0.6875
12	0.75
13	0.8125
14	0.875
15	0.9375
16	1
17	1.0625
18	1.125
19	1.1875
20	1.25
21	1.3125
22	1.375
23	1.4375
24	1.5
25	1.5625
26	1.625
27	1.6875
28	1.75
29	1.8125
30	1.875
31	1.9375
32	2
33	2.0625
34	2.125
35	2.1875
36	2.25
37	2.3125
38	2.375
39	2.4375
40	2.5
41	2.5625
42	2.625
43	2.6875
44	2.75
45	2.8125
46	2.875
47	2.9375
48	3
49	3.0625
50	3.125

Common Units of Measure - 15px, 16px (1rem), and 30px Multiples List

The Bootstrap grid defaults to 15px padding on the left and right of each column. So that makes a 30px gutter between two columns. When you are working on a design you will probably want to work with these common units of measure to determine heights of objects.

Multiples of 15px	Multiples of 30px	Multiples of 16px
2	15	30	16
3	30	60	32
4	45	90	48
5	60	120	64
6	75	150	80
7	90	180	96
8	105	210	112
9	120	240	128
10	135	270	144
11	150	300	160
12	165	330	176
13	180	360	192
14	195	390	208
15	210	420	224
16	225	450	240
17	240	480	256
18	255	510	272
19	270	540	288
20	285	570	304
21	300	600	320
22	315	630	336
23	330	660	352
24	345	690	368
25	360	720	384
26	375	750	400
27	390	780	416
28	405	810	432
29	420	840	448
30	435	870	464
31	450	900	480
32	465	930	496
33	480	960	512
34	495	990	528
35	510	1020	544
36	525	1050	560
37	540	1080	576
38	555	1110	592
39	570	1140	608
40	585	1170	624
41	600	1200	640
42	615	1230	656
43	630	1260	672
44	645	1290	688
45	660	1320	704
46	675	1350	720
47	690	1380	736
48	705	1410	752
49	720	1440	768
50	735	1470	784
51	750	1500	800
52	765	1530	816
53	780	1560	832
54	795	1590	848
55	810	1620	864
56	825	1650	880
57	840	1680	896
58	855	1710	912
59	870	1740	928
60	885	1770	944
61	900	1800	960
62	915	1830	976
63	930	1860	992
64	945	1890	1008
65	960	1920	1024
66	975	1950	1040
67	990	1980	1056
68	1005	2010	1072
69	1020	2040	1088
70	1035	2070	1104
71	1050	2100	1120
72	1065	2130	1136
73	1080	2160	1152
74	1095	2190	1168
75	1110	2220	1184
76	1125	2250	1200
77	1140	2280	1216
78	1155	2310	1232
79	1170	2340	1248
80	1185	2370	1264
81	1200	2400	1280
82	1215	2430	1296
83	1230	2460	1312
84	1245	2490	1328
85	1260	2520	1344
86	1275	2550	1360
87	1290	2580	1376
88	1305	2610	1392
89	1320	2640	1408
90	1335	2670	1424
91	1350	2700	1440
92	1365	2730	1456
93	1380	2760	1472
94	1395	2790	1488
95	1410	2820	1504
96	1425	2850	1520
97	1440	2880	1536
98	1455	2910	1552
99	1470	2940	1568
100	1485	2970	1584

Sources: Bootstrap 4 Classes List