Change CSS framework from PicoCSS to Bootstrap 5.3

assets/bs/litera/_bootswatch.scss

@@ -0,0 +1,98 @@
+// Litera 5.3.8
+// Bootswatch
+
+
+// Variables
+
+// Navbar
+
+.navbar {
+  font-size: $font-size-sm;
+}
+
+// Typography
+
+p {
+  font-family: $font-family-serif;
+}
+
+blockquote {
+  font-style: italic;
+}
+
+footer {
+  font-size: $font-size-sm;
+}
+
+.lead {
+  font-family: $font-family-sans-serif;
+  color: $gray-600;
+}
+
+// Tables
+
+table,
+.table {
+  font-size: $font-size-sm;
+}
+
+// Navs
+
+.nav,
+.breadcrumb,
+.pagination {
+  font-size: $font-size-sm;
+}
+
+.dropdown-menu {
+  font-size: $font-size-sm;
+}
+
+// Indicators
+
+.alert {
+  font-size: $font-size-sm;
+  color: $white;
+
+  &,
+  p {
+    font-family: $font-family-sans-serif;
+  }
+
+  a,
+  .alert-link {
+    font-weight: 400;
+    color: $white;
+    text-decoration: underline;
+  }
+
+  @each $color, $value in $theme-colors {
+    &-#{$color} {
+      @if $enable-gradients {
+        background: $value linear-gradient($value, mix($body-bg, $value, 15%)) repeat-x;
+      } @else {
+        background-color: $value;
+      }
+    }
+  }
+
+  &-light {
+    &,
+    a,
+    .alert-link {
+      color: $body-color;
+    }
+  }
+}
+
+.badge {
+  &.bg-light {
+    color: $dark;
+  }
+}
+
+// Containers
+
+.list-group {
+  font-size: $font-size-sm;
+}

assets/bs/litera/_variables.scss

@@ -0,0 +1,97 @@
+// Litera 5.3.8
+// Bootswatch
+
+$theme: "litera" !default;
+
+//
+// Color system
+//
+
+$white:    #fff !default;
+$gray-100: #f8f9fa !default;
+$gray-200: #e9ecef !default;
+$gray-300: #ddd !default;
+$gray-400: #ced4da !default;
+$gray-500: #adb5bd !default;
+$gray-600: #868e96 !default;
+$gray-700: #495057 !default;
+$gray-800: #343a40 !default;
+$gray-900: #212529 !default;
+$black:    #000 !default;
+
+$blue:    #4582ec !default;
+$indigo:  #6610f2 !default;
+$purple:  #6f42c1 !default;
+$pink:    #e83e8c !default;
+$red:     #d9534f !default;
+$orange:  #fd7e14 !default;
+$yellow:  #f0ad4e !default;
+$green:   #02b875 !default;
+$teal:    #20c997 !default;
+$cyan:    #17a2b8 !default;
+
+$primary:       $blue !default;
+$secondary:     $gray-500 !default;
+$success:       $green !default;
+$info:          $cyan !default;
+$warning:       $yellow !default;
+$danger:        $red !default;
+$light:         $gray-100 !default;
+$dark:          $gray-800 !default;
+
+$min-contrast-ratio:   1.85 !default;
+
+// Body
+
+$body-color:                $gray-800 !default;
+
+// Fonts
+
+// stylelint-disable value-keyword-case
+$font-family-sans-serif:      -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji" !default;
+$font-family-serif:           Georgia, Cambria, "Times New Roman", Times, serif !default;
+// stylelint-enable
+
+$font-size-base:              1.1rem !default;
+$headings-font-weight:        700 !default;
+
+// Tables
+
+$table-color:                 initial !default;
+
+$table-border-color:          rgba(0, 0, 0, .1) !default;
+
+$table-bg-scale:              0% !default;
+
+// Buttons
+
+$input-btn-padding-y:         .5rem !default;
+$input-btn-padding-x:         1.1rem !default;
+$btn-font-family:             $font-family-sans-serif !default;
+$btn-font-size:               .875rem !default;
+$btn-font-size-sm:            .688rem !default;
+
+$btn-border-radius:           1.078em !default;
+$btn-border-radius-lg:        2.688em !default;
+$btn-border-radius-sm:        .844em !default;
+
+// Forms
+
+$input-border-color:                    rgba(0, 0, 0, .1) !default;
+$input-group-addon-bg:                  $gray-200 !default;
+
+// Navbar
+
+// Tooltips
+
+$tooltip-font-size:                 11px !default;
+
+// Badges
+
+$badge-font-weight:                 400 !default;
+$badge-padding-y:                   .6em !default;
+$badge-padding-x:                   1.2em !default;
+
+// Alerts
+
+$alert-border-width:                0 !default;