bootstrap/scss/buttons/_button.scss

@use "sass:color";
@use "sass:list";
@use "sass:map";
@use "sass:meta";
@use "../colors" as *;
@use "../config" as *;
@use "../theme" as *;
@use "../variables" as *;
@use "../theme" as *;
@use "../functions" as *;
@use "../vendor/rfs" as *;
@use "../mixins/border-radius" as *;
@use "../mixins/box-shadow" as *;
@use "../mixins/focus-ring" as *;
@use "../mixins/gradients" as *;
@use "../mixins/transition" as *;
@use "button-variables" as *;

// scss-docs-start btn-variants
$button-variants: (
  "solid": (
    "base": (
      "bg": "bg",
      "color": "contrast",
      "border-color": "bg"
    ),
    "hover": (
      "bg": "bg",
      "border-color": "bg",
      "color": "contrast"
    ),
    "active": (
      "bg": "bg",
      "border-color": "bg",
      "color": "contrast"
    )
  ),
  "outline": (
    "base": (
      "bg": "transparent",
      "color": "text",
      "border-color": "border"
    ),
    "hover": (
      "bg": "bg",
      "color": "contrast",
      "border-color": "bg"
    ),
    "active": (
      "bg": "bg",
      "color": "contrast",
      "border-color": "bg"
    )
  ),
  "subtle": (
    "base": (
      "bg": "bg-subtle",
      "color": "text",
      "border-color": "transparent"
    ),
    "hover": (
      "bg": ("bg-muted", "bg-subtle"),
      "color": "text"
    ),
    "active": (
      "bg": "bg-subtle",
      "color": "text"
    )
  ),
  "text": (
    "base": (
      "color": "text",
      "bg": "transparent",
      "border-color": "transparent"
    ),
    "hover": (
      "color": "text",
      "bg": "bg-subtle"
    ),
    "active": (
      "color": "text",
      "bg": "bg-subtle"
    )
  )
) !default;
// scss-docs-end btn-variants


// Helper function to get nested map values using dot notation
@function get-nested-value($map, $keys) {
  $value: $map;
  @each $key in $keys {
    @if type-of($value) == "map" {
      $value: map-get($value, $key);
    } @else {
      @return null;
    }
  }
  @return $value;
}

// Helper function to split dot notation string into list
@function split-keys($key) {
  $keys: ();
  $parts: str-slice($key, 1);
  @each $part in $parts {
    $keys: append($keys, $part);
  }
  @return $keys;
}

// Main button style generator mixin
// scss-docs-start btn-variant-mixin
@mixin button-variant($color, $variant) {
  $variant-styles: map.get($button-variants, $variant);

  @if $variant-styles {
    // Base properties
    @each $property, $value in map.get($variant-styles, "base") {
      @if $value == "transparent" {
        --#{$prefix}btn-#{$property}: transparent;
      } @else {
        --#{$prefix}btn-#{$property}: var(--#{$prefix}#{$color}-#{$value});
      }
    }

    // Hover state
    &:hover {
      @each $property, $value in map.get($variant-styles, "hover") {
        @if $value == "transparent" {
          --#{$prefix}btn-hover-#{$property}: transparent;
        } @else if meta.type-of($value) == "list" {
          $first-value: list.nth($value, 1);
          $second-value: list.nth($value, 2);
          --#{$prefix}btn-hover-#{$property}: color-mix(in oklch, var(--#{$prefix}#{$color}-#{$first-value}) 50%, var(--#{$prefix}#{$color}-#{$second-value}));
        } @else if $value == "bg-subtle" {
          --#{$prefix}btn-hover-#{$property}: var(--#{$prefix}#{$color}-#{$value});
        } @else {
          --#{$prefix}btn-hover-#{$property}: oklch(from var(--#{$prefix}#{$color}-#{$value}) calc(l * .95) calc(c * 1.1) h);
        }
      }
    }

    &:focus-visible {
      outline-color: var(--#{$prefix}#{$color}-focus-ring);
    }

    // Active state
    &:active,
    &.active {
      @each $property, $value in map.get($variant-styles, "active") {
        @if $value == "transparent" {
          --#{$prefix}btn-active-#{$property}: transparent;
        } @else if $value == "bg-subtle" {
          --#{$prefix}btn-active-#{$property}: var(--#{$prefix}#{$color}-#{$value});
        } @else {
          --#{$prefix}btn-active-#{$property}: oklch(from var(--#{$prefix}#{$color}-#{$value}) calc(l * .9) calc(c * 1.15) h);
        }
      }
    }
  }
}
// scss-docs-end btn-variant-mixin

// Generate all button variants
@each $color, $_ in $new-theme-colors {
  @each $variant, $_ in $button-variants {
    .btn-#{$color}-#{$variant} {
      @include button-variant($color, $variant);
    }
  }
}

// scss-docs-start btn-size-mixin
@mixin button-size($padding-y, $padding-x, $font-size, $border-radius) {
  --#{$prefix}btn-padding-y: #{$padding-y};
  --#{$prefix}btn-padding-x: #{$padding-x};
  @include rfs($font-size, --#{$prefix}btn-font-size);
  --#{$prefix}btn-border-radius: #{$border-radius};
}
// scss-docs-end btn-size-mixin


//
// Base styles
//

@layer components {
  .btn {
    // scss-docs-start btn-css-vars
    --#{$prefix}btn-padding-x: #{$btn-padding-x};
    --#{$prefix}btn-padding-y: #{$btn-padding-y};
    --#{$prefix}btn-font-family: #{$btn-font-family};
    @include rfs($btn-font-size, --#{$prefix}btn-font-size);
    --#{$prefix}btn-font-weight: #{$btn-font-weight};
    --#{$prefix}btn-line-height: #{$btn-line-height};
    --#{$prefix}btn-color: #{$btn-color};
    --#{$prefix}btn-bg: transparent;
    --#{$prefix}btn-border-width: #{$btn-border-width};
    --#{$prefix}btn-border-color: transparent;
    --#{$prefix}btn-border-radius: #{$btn-border-radius};
    --#{$prefix}btn-hover-border-color: transparent;
    --#{$prefix}btn-box-shadow: #{$btn-box-shadow};
    --#{$prefix}btn-disabled-opacity: #{$btn-disabled-opacity};
    // --#{$prefix}btn-focus-box-shadow: 0 0 0 #{$btn-focus-width} rgba(var(--#{$prefix}btn-focus-shadow-rgb), .5);
    // scss-docs-end btn-css-vars

    display: inline-block;
    padding: var(--#{$prefix}btn-padding-y) var(--#{$prefix}btn-padding-x);
    font-family: var(--#{$prefix}btn-font-family);
    @include font-size(var(--#{$prefix}btn-font-size));
    font-weight: var(--#{$prefix}btn-font-weight);
    line-height: var(--#{$prefix}btn-line-height);
    color: var(--#{$prefix}btn-color);
    text-align: center;
    text-decoration: if($link-decoration == none, null, none);
    white-space: $btn-white-space;
    vertical-align: middle;
    cursor: if($enable-button-pointers, pointer, null);
    user-select: none;
    border: var(--#{$prefix}btn-border-width) solid var(--#{$prefix}btn-border-color);
    @include border-radius(var(--#{$prefix}btn-border-radius));
    @include gradient-bg(var(--#{$prefix}btn-bg));
    @include box-shadow(var(--#{$prefix}btn-box-shadow));
    @include transition($btn-transition);

    &:hover {
      color: var(--#{$prefix}btn-hover-color);
      text-decoration: if($link-hover-decoration == underline, none, null);
      background-color: var(--#{$prefix}btn-hover-bg);
      border-color: var(--#{$prefix}btn-hover-border-color);
    }

    .btn-check + &:hover {
      // override for the checkbox/radio buttons
      color: var(--#{$prefix}btn-color);
      background-color: var(--#{$prefix}btn-bg);
      border-color: var(--#{$prefix}btn-border-color);
    }

    &:focus-visible {
      @include focus-ring(true);
      --#{$prefix}focus-ring-offset: 1px;
    }

    .btn-check:focus-visible + & {
      @include focus-ring(true);
    }

    .btn-check:checked + &,
    :not(.btn-check) + &:active,
    &:first-child:active,
    &.active,
    &.show {
      color: var(--#{$prefix}btn-active-color);
      background-color: var(--#{$prefix}btn-active-bg);
      // Remove CSS gradients if they're enabled
      background-image: if($enable-gradients, none, null);
      border-color: var(--#{$prefix}btn-active-border-color);
      @include box-shadow(var(--#{$prefix}btn-active-shadow));

      &:focus-visible {
        @include focus-ring(true);
      }
    }

    .btn-check:checked:focus-visible + & {
      @include focus-ring(true);
    }

    &:disabled,
    &.disabled,
    fieldset:disabled & {
      color: var(--#{$prefix}btn-disabled-color);
      pointer-events: none;
      background-color: var(--#{$prefix}btn-disabled-bg);
      background-image: if($enable-gradients, none, null);
      border-color: var(--#{$prefix}btn-disabled-border-color);
      opacity: var(--#{$prefix}btn-disabled-opacity);
      @include box-shadow(none);
    }
  }

  //
  // Link buttons
  //

  // Make a button look and behave like a link
  .btn-link {
    --#{$prefix}btn-font-weight: #{$font-weight-normal};
    --#{$prefix}btn-color: #{$btn-link-color};
    --#{$prefix}btn-bg: transparent;
    --#{$prefix}btn-border-color: transparent;
    --#{$prefix}btn-hover-color: #{$btn-link-hover-color};
    --#{$prefix}btn-hover-border-color: transparent;
    --#{$prefix}btn-active-color: #{$btn-link-hover-color};
    --#{$prefix}btn-active-border-color: transparent;
    --#{$prefix}btn-disabled-color: #{$btn-link-disabled-color};
    --#{$prefix}btn-disabled-border-color: transparent;
    --#{$prefix}btn-box-shadow: 0 0 0 #000; // Can't use `none` as keyword negates all values when used with multiple shadows
    // --#{$prefix}btn-focus-shadow-rgb: #{$btn-link-focus-shadow-rgb};

    text-decoration: $link-decoration;
    @if $enable-gradients {
      background-image: none;
    }

    &:hover,
    &:focus-visible {
      text-decoration: $link-hover-decoration;
    }

    &:focus-visible {
      color: var(--#{$prefix}btn-color);
    }

    &:hover {
      color: var(--#{$prefix}btn-hover-color);
    }

    // No need for an active state here
  }


  //
  // Button Sizes
  //

  .btn-lg {
    @include button-size($btn-padding-y-lg, $btn-padding-x-lg, $btn-font-size-lg, $btn-border-radius-lg);
  }

  .btn-sm {
    @include button-size($btn-padding-y-sm, $btn-padding-x-sm, $btn-font-size-sm, $btn-border-radius-sm);
  }

  .btn-check {
    position: absolute;
    clip: rect(0, 0, 0, 0);
    pointer-events: none;

    &[disabled],
    &:disabled {
      + .btn {
        pointer-events: none;
        filter: none;
        opacity: .65;
      }
    }
  }
}