重要的目录结构

• /bootstrap/scss/**/*
• /bootstrap/js/**/*
• /bootstrap/build/**/*

需要的知识

• Sass/Scss, 重点是在 scss

下面会说，具体用到了哪些 scss 的知识点

对外暴露

• /bootstrap/scss/bootstrap.scss

/*!
 * Bootstrap v4.3.1 (https://getbootstrap.com/)
 * Copyright 2011-2020 The Bootstrap Authors
 * Copyright 2011-2020 Twitter, Inc.
 * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
 */

// Configuration

@import "functions";
@import "variables";
@import "mixins";
@import "utilities";


// Layout & components

@import "root";
@import "reboot";
@import "type";
@import "images";
@import "containers";
@import "grid";
@import "tables";
@import "forms";
@import "buttons";
@import "transitions";
@import "dropdown";
@import "button-group";
@import "nav";
@import "navbar";
@import "card";
@import "breadcrumb";
@import "pagination";
@import "badge";
@import "alert";
@import "progress";
@import "list-group";
@import "close";
@import "toasts";
@import "modal";
@import "tooltip";
@import "popover";
@import "carousel";
@import "spinners";


// Helpers

@import "helpers";


// Utilities

@import "utilities/api";

• /bootstrap/scss/bootstrap-utilities.scss

/*!
 * Bootstrap Utilities v4.3.1 (https://getbootstrap.com/)
 * Copyright 2011-2020 The Bootstrap Authors
 * Copyright 2011-2020 Twitter, Inc.
 * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
 */

// Configuration

@import "functions";
@import "variables";
@import "mixins";
@import "utilities";


// Utilities

@import "utilities/api";

• /bootstrap/scss/bootstrap-reboot.scss

/*!
 * Bootstrap Reboot v4.3.1 (https://getbootstrap.com/)
 * Copyright 2011-2020 The Bootstrap Authors
 * Copyright 2011-2020 Twitter, Inc.
 * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
 * Forked from Normalize.css, licensed MIT (https://github.com/necolas/normalize.css/blob/master/LICENSE.md)
 */

@import "functions";
@import "variables";
@import "mixins";
@import "reboot";

• /bootstrap/scss/bootstrap-grid.scss

/*!
 * Bootstrap Grid v4.3.1 (https://getbootstrap.com/)
 * Copyright 2011-2020 The Bootstrap Authors
 * Copyright 2011-2020 Twitter, Inc.
 * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
 */

html {
  box-sizing: border-box;
}

*,
*::before,
*::after {
  box-sizing: inherit;
}

@import "functions";
@import "variables";

@import "mixins/breakpoints";
@import "mixins/container";
@import "mixins/grid";
@import "mixins/utilities";

@import "vendor/rfs";

@import "containers";
@import "grid";

@import "utilities";
// Only use the utilities we need
// stylelint-disable-next-line scss/dollar-variable-default
$utilities: map-get-multiple(
  $utilities,
  (
    "display",
    "order",
    "flex",
    "flex-direction",
    "flex-grow",
    "flex-shrink"
    "flex-wrap",
    "justify-content",
    "align-items",
    "align-content",
    "align-self",
    "margin",
    "margin-x",
    "margin-y",
    "margin-top",
    "margin-right",
    "margin-bottom",
    "margin-left",
    "negative-margin",
    "negative-margin-x",
    "negative-margin-y",
    "negative-margin-top",
    "negative-margin-right",
    "negative-margin-bottom",
    "negative-margin-left",
    "padding",
    "padding-x",
    "padding-y",
    "padding-top",
    "padding-right",
    "padding-bottom",
    "padding-left",
  )
);

@import "utilities/api";