webawesome/src/components/button/button.css

@layer wa-component {
  :host {
    --background-color: var(--wa-color-fill-loud, var(--wa-color-neutral-fill-loud));
    --background-color-hover: color-mix(in oklab, var(--background-color), var(--wa-color-mix-hover));
    --background-color-active: color-mix(in oklab, var(--background-color), var(--wa-color-mix-active));

    --border-color: transparent;
    --border-color-hover: var(--border-color);
    --border-color-active: var(--border-color);
    --border-width: max(1px, var(--wa-form-control-border-width));

    --box-shadow: initial;

    --text-color: var(--wa-color-on-loud, var(--wa-color-neutral-on-loud));
    --text-color-hover: var(--text-color);
    --text-color-active: var(--text-color);

    display: inline-block;
    position: relative;
  }
}

.button {
  border-radius: var(--wa-form-control-border-radius);
  border-style: var(--wa-border-style);
  border-width: var(--border-width);
  box-shadow: var(--box-shadow);
  align-items: center;
  justify-content: center;
  text-decoration: none;
  user-select: none;
  -webkit-user-select: none;
  white-space: nowrap;
  vertical-align: middle;
  transition-property: background, border, box-shadow, color;
  transition-duration: var(--wa-transition-fast);
  transition-timing-function: var(--wa-transition-easing);
  cursor: pointer;
  padding: 0 var(--wa-space, var(--wa-space-m));
  font-family: inherit;
  font-size: var(--wa-size, var(--wa-font-size-m));
  font-weight: var(--wa-font-weight-action);
  line-height: calc(var(--wa-form-control-height) - var(--border-width) * 2);
  height: var(--wa-form-control-height);
  width: 100%;

  display: inline-flex;
  background-color: var(--background-color);
  border-color: var(--border-color, var(--background-color));
  color: var(--text-color);
}

/* Interactive states */
.button:not(.disabled):not(.loading):hover {
  background-color: var(--background-color-hover, var(--background-color));
  border-color: var(--border-color-hover, var(--border-color, var(--background-color-hover)));
  color: var(--text-color-hover, var(--text-color));
}

.button:not(.disabled):not(.loading):active {
  background-color: var(--background-color-active, var(--background-color));
  border-color: var(--border-color-active, var(--border-color, var(--background-color-active)));
  color: var(--text-color-active, var(--text-color));
}

/* Focus states */
.button:focus {
  outline: none;
}

.button:focus-visible {
  outline: var(--wa-focus-ring);
  outline-offset: var(--wa-focus-ring-offset);
}

/* Disabled state */
.button.disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

/* When disabled, prevent mouse events from bubbling up from children */
.button.disabled * {
  pointer-events: none;
}

/* Keep it last so Safari doesn't stop parsing this block */
.button::-moz-focus-inner {
  border: 0;
}

/* Pill modifier */
:host([pill]) .button {
  border-radius: var(--wa-border-radius-pill);
}

/*
 * Label
 */

.prefix,
.suffix {
  flex: 0 0 auto;
  display: flex;
  align-items: center;
  pointer-events: none;
}

.label {
  display: inline-block;
}

.label::slotted(wa-icon) {
  vertical-align: -2px;
}

/*
 * Caret modifier
 */

wa-icon[part~='caret'] {
  display: flex;
  align-self: center;
  align-items: center;

  &::part(svg) {
    width: 0.875em;
    height: 0.875em;
  }

  .button:has(&) .suffix {
    display: none;
  }
}

/*
 * Loading modifier
 */

.loading {
  position: relative;
  cursor: wait;

  .prefix,
  .label,
  .suffix,
  .caret {
    visibility: hidden;
  }

  wa-spinner {
    --indicator-color: currentColor;
    --track-color: color-mix(in oklab, currentColor, transparent 90%);

    position: absolute;
    font-size: 1em;
    height: 1em;
    width: 1em;
    top: calc(50% - 0.5em);
    left: calc(50% - 0.5em);
  }
}

/*
 * Badges
 */
button ::slotted(wa-badge) {
  border-color: var(--wa-color-surface-default);
  position: absolute;
  inset-block-start: 0;
  inset-inline-end: 0;
  translate: 50% -50%;
  pointer-events: none;
}

:host(:dir(rtl)) ::slotted(wa-badge) {
  translate: -50% -50%;
}

/*
* Button spacing
*/

slot[name='prefix']::slotted(*) {
  margin-inline-end: var(--wa-space);
}

slot[name='suffix']::slotted(*),
.button:not(.visually-hidden-label) [part~='caret'] {
  margin-inline-start: var(--wa-space);
}

/*
 * Button group border radius modifications
 */

/* Remove border radius from all grouped buttons by default */
:host(.wa-button-group__button) .button {
  border-radius: 0;
}

/* Horizontal orientation */
:host(.wa-button-group__horizontal.wa-button-group__button-first) .button {
  border-start-start-radius: var(--wa-form-control-border-radius);
  border-end-start-radius: var(--wa-form-control-border-radius);
}

:host(.wa-button-group__horizontal.wa-button-group__button-last) .button {
  border-start-end-radius: var(--wa-form-control-border-radius);
  border-end-end-radius: var(--wa-form-control-border-radius);
}

/* Vertical orientation */
:host(.wa-button-group__vertical) {
  flex: 1 1 auto;
}

:host(.wa-button-group__vertical) .button {
  width: 100%;
  justify-content: start;
}

:host(.wa-button-group__vertical.wa-button-group__button-first) .button {
  border-start-start-radius: var(--wa-form-control-border-radius);
  border-start-end-radius: var(--wa-form-control-border-radius);
}

:host(.wa-button-group__vertical.wa-button-group__button-last) .button {
  border-end-start-radius: var(--wa-form-control-border-radius);
  border-end-end-radius: var(--wa-form-control-border-radius);
}

/* Handle pill modifier for button groups */
:host([pill]) .wa-button-group__horizontal.wa-button-group__button-first {
  border-start-start-radius: var(--wa-border-radius-pill);
  border-end-start-radius: var(--wa-border-radius-pill);
}

:host([pill]) .wa-button-group__horizontal.wa-button-group__button-last {
  border-start-end-radius: var(--wa-border-radius-pill);
  border-end-end-radius: var(--wa-border-radius-pill);
}

:host([pill]) .wa-button-group__vertical.wa-button-group__button-first {
  border-start-start-radius: var(--wa-border-radius-pill);
  border-start-end-radius: var(--wa-border-radius-pill);
}

:host([pill]) .wa-button-group__vertical.wa-button-group__button-last {
  border-end-start-radius: var(--wa-border-radius-pill);
  border-end-end-radius: var(--wa-border-radius-pill);
}