bulma/sass/elements/button.sass

=button-small
  border-radius: $radius-small
  font-size: $size-small
=button-medium
  font-size: $size-medium
=button-large
  font-size: $size-large

.button
  +control
  +unselectable
  cursor: pointer
  justify-content: center
  padding-left: 1em
  padding-right: 1em
  text-align: center
  white-space: nowrap
  strong
    color: inherit
  .icon,
  .tag
    &:first-child
      margin-left: -2px
      margin-right: 4px
    &:last-child
      margin-left: 4px
      margin-right: -2px
  &:hover,
  &:focus,
  &.is-active
    color: $control-hover
  &:active
    box-shadow: inset 0 1px 2px rgba($black, 0.2)
  // Colors
  @each $name, $pair in $colors
    $color: nth($pair, 1)
    $color-invert: nth($pair, 2)
    &.is-#{$name}
      background-color: $color
      border-width: 0
      color: $color-invert
      &:hover,
      &:focus,
      &.is-active
        background-color: darken($color, 5%)
        border-color: transparent
        color: $color-invert
      &.is-inverted
        background-color: $color-invert
        color: $color
        &:hover
          background-color: darken($color-invert, 5%)
      &.is-loading
        &:after
          border-color: transparent transparent $color-invert $color-invert !important
      &.is-outlined
        background-color: transparent
        border-color: $color
        border-width: 1px
        color: $color
        &:hover,
        &:focus
          background-color: $color
          border-color: $color
          color: $color-invert
  &.is-link
    background-color: transparent
    border-width: 0
    color: $text
    text-decoration: underline
    &:hover,
    &:focus
      background-color: $background
      color: $text-strong
  // Sizes
  &.is-small
    +button-small
  &.is-medium
    +button-medium
  &.is-large
    +button-large
  // Modifiers
  &[disabled],
  &.is-disabled
    opacity: 0.5
  &.is-fullwidth
    display: flex
    width: 100%
  &.is-loading
    color: transparent !important
    pointer-events: none
    &:after
      +loader
      +center(16px)
      position: absolute !important