mdb-ui-kit/scss/includes/_buttons.scss

// specification: https://www.google.com/design/spec/components/buttons.html

@mixin typo-button($colorContrast: false){
  font-size: $mdb-btn-font-size-base;
  font-weight: 500;
  text-transform: uppercase;
  //line-height: 1;
  letter-spacing: 0;

  @if ($colorContrast) {
    opacity: 0.87;
  }
}

// mdb default buttons are flat by default
// synchronized with mdl 11/23/15
.btn,
.input-group-btn .btn {
  border: none;
  border-radius: $border-radius-base;
  position: relative;
  padding: 8px 30px;
  margin: 10px 1px;
  @include typo-button();
  will-change: box-shadow, transform;
  transition: box-shadow 0.2s $mdb-animation-curve-fast-out-linear-in,
  background-color 0.2s $mdb-animation-curve-default,
  color 0.2s $mdb-animation-curve-default;
  outline: none;
  cursor: pointer;
  text-decoration: none;

  &::-moz-focus-inner {
    border: 0;
  }

  //---
  // btn-flat
  background: transparent;
  &:not(.btn-raised) {
    @include variations(unquote(".btn"), unquote(""), color, $mdb-text-color-primary);
    box-shadow: none;

    &:not(.btn-link) {
      &:hover,
      &:focus {
        // spec: flat/light bg Hover: 20% #999999
        background-color: rgba(#999999, (20/100));

        .theme-dark & {
          // spec: dark bg Hover: 15% #CCCCCC
          background-color: rgba(#CCCCCC, (15/100));
        }
      }
    }
  }

  //--
  // color variations
  &.btn-raised,
  &.btn-fab {
    @include background-variations(unquote(".btn"), unquote(""), $mdb-btn-background-color);
  }


  //---
  // btn-raised
  &.btn-raised {
    &:not(.btn-link) {
      @include shadow-2dp();

      &:hover {

        // Spec:
        //  - Raised Light/Light theme no hover.
        //  - Raised Dark/Dark theme Hover color: 600
        .theme-dark & {
          //// SASS conversion note: please mirror any content change in _mixins-shared.scss button-variations-content
          //@include alert-variations(unquote(".btn"), unquote(""), $mdb-btn-background-color);
        }
      }

      &.active,
      &:active {
        @include shadow-4dp();
      }

      &:focus:not(:active) {
        @include focus-shadow();
      }
    }
  }

  &.btn-fab {
    // see above for color variations
    border-radius: 50%;
    font-size: $mdb-btn-fab-font-size;
    height: $mdb-btn-fab-size;
    margin: auto;
    min-width: $mdb-btn-fab-size;
    width: $mdb-btn-fab-size;
    padding: 0;
    overflow: hidden;
    box-shadow: 0 1px 1.5px 0 rgba(0, 0, 0, 0.12), 0 1px 1px 0 rgba(0, 0, 0, 0.24);
    position: relative;
    line-height: normal;

    .ripple-container {
      border-radius: 50%;
    }

    &.btn-fab-mini,
    .btn-group-sm & {
      height: $mdb-btn-fab-size-mini;
      min-width: $mdb-btn-fab-size-mini;
      width: $mdb-btn-fab-size-mini;

      &.material-icons {
        top: ($mdb-btn-icon-size-mini - $mdb-btn-fab-font-size) / 2;
        left: ($mdb-btn-icon-size-mini - $mdb-btn-fab-font-size) / 2;
      }
    }

    i.material-icons {
      position: absolute;
      top: 50%;
      left: 50%;
      transform: translate(-($mdb-btn-fab-font-size / 2), -($mdb-btn-fab-font-size / 2));
      line-height: $mdb-btn-fab-font-size;
      width: $mdb-btn-fab-font-size;
    }
  }

  // Align icons inside buttons with text
  i.material-icons {
    vertical-align: middle;
  }


  // Size variations
  &.btn-lg,
  .btn-group-lg & {
    font-size: $mdb-btn-font-size-lg;
  }
  &.btn-sm,
  .btn-group-sm & {
    padding: 5px 20px;
    font-size: $mdb-btn-font-size-sm;
  }
  &.btn-xs,
  .btn-group-xs & {
    padding: 4px 15px;
    font-size: $mdb-btn-font-size-xs;
  }
}

// Disabled buttons and button groups
.btn,
.input-group-btn .btn,
.btn-group,
.btn-group-vertical {
  // have to ratchet up the specificity to kill drop shadows on disabled raised buttons
  fieldset[disabled][disabled] &,
  &.disabled,
  &:disabled,
  &[disabled][disabled] {
    // spec: light theme: Disabled text: 26% #000000
    color: rgba(#000000, (26/100));
    .theme-dark & {
      // spec: dark theme: Disabled text: 30% #FFFFFF
      color: rgba(#FFFFFF, (30/100));
    }

    // flat buttons lose transparency
    background: transparent;

    // no box-shadow on raised - need specificity
    &.btn-raised,
    &.btn-group-raised {
      &,
      &.active,
      &:active,
      &:focus:not(:active) {
        box-shadow: none;
      }
    }
  }
}

// btn-group variations
.btn-group,
.btn-group-vertical {

  position: relative;
  //border-radius: 2px;
  margin: 10px 1px;


  // spec: https://www.google.com/design/spec/components/buttons.html#buttons-toggle-buttons
  &.open {
    .dropdown-toggle {
      //box-shadow: none;
    }

    & > .dropdown-toggle.btn {
      @include variations(unquote(".btn"), unquote(""), background-color, $mdb-btn-background-color);
    }
  }

  .dropdown-menu {
    border-radius: 0 0 $border-radius-base $border-radius-base;
  }

  &.btn-group-raised {
    @include shadow-2dp();
  }

  & .btn + .btn,
  .btn,
  .btn:active,
  .btn-group {
    margin: 0;
  }
}