/* ============================================================
   Button component – Workspace / GM3 inspired
   Variants:
   - .btn
   - .btn--filled
   - .btn--tonal
   - .btn--outlined
   - .btn--text
   - .btn--icon
   - .btn--fab
   - Sizes: .btn--sm .btn--lg
   - State: .is-loading
   ============================================================ */
/* =========================
   Base button
   ========================= */
.btn {
  --btn-h: 40px;
  --btn-px: 16px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  height: var(--btn-h);
  padding: 0 var(--btn-px);
  border-radius: var(--r-pill);
  border: 1px solid transparent;
  font-size: var(--fs-14);
  font-weight: var(--fw-500);
  line-height: 1;
  cursor: pointer;
  user-select: none;
  transition: background var(--dur-2) var(--ease-out), color var(--dur-2) var(--ease-out), border-color var(--dur-2) var(--ease-out), box-shadow var(--dur-2) var(--ease-out), transform var(--dur-1) var(--ease-out);
}
.btn:focus-visible {
  box-shadow: var(--focus-ring);
}
.btn:active {
  transform: translateY(1px);
}
.btn:disabled,
.btn.is-disabled {
  opacity: 0.5;
  cursor: not-allowed;
  pointer-events: none;
}
/* =========================
   Filled (Primary)
   ========================= */
.btn--filled {
  background: var(--c-primary);
  color: var(--c-on-primary);
  box-shadow: var(--e-1);
}
.btn--filled:hover {
  filter: brightness(0.96);
}
.btn--filled:active {
  box-shadow: var(--e-0);
}
/* =========================
   Tonal (Workspace light blue)
   ========================= */
.btn--tonal {
  background: rgba(11, 87, 208, 0.12);
  color: var(--c-primary);
}
.btn--tonal:hover {
  background: rgba(11, 87, 208, 0.18);
}
.btn--tonal:active {
  background: rgba(11, 87, 208, 0.24);
}
/* =========================
   Outlined
   ========================= */
.btn--outlined {
  background: var(--c-surface);
  color: var(--c-text-2);
  border-color: var(--c-outline-strong);
}
.btn--outlined:hover {
  background: rgba(0, 0, 0, 0.04);
}
.btn--outlined:focus-visible {
  border-color: var(--focus-border);
}
/* =========================
   Text button
   ========================= */
.btn--text {
  background: transparent;
  color: var(--c-primary);
}
.btn--text:hover {
  background: rgba(11, 87, 208, 0.08);
}
/* =========================
   Icon button (round)
   ========================= */
.btn--icon {
  width: 40px;
  height: 40px;
  padding: 0;
  border-radius: var(--r-pill);
  background: transparent;
  color: var(--c-text-2);
}
.btn--icon:hover {
  background: rgba(0, 0, 0, 0.05);
}
/* =========================
   Floating Action Button
   ========================= */
.btn--fab {
  width: 56px;
  height: 56px;
  padding: 0;
  border-radius: var(--r-16);
  background: var(--c-primary);
  color: var(--c-on-primary);
  box-shadow: var(--e-2);
}
.btn--fab:hover {
  filter: brightness(0.96);
}
.btn--fab:focus-visible {
  box-shadow: var(--focus-ring), var(--e-2);
}
/* =========================
   Size modifiers
   ========================= */
.btn--sm {
  --btn-h: 32px;
  --btn-px: 12px;
  font-size: var(--fs-13);
}
.btn--lg {
  --btn-h: 48px;
  --btn-px: 20px;
  font-size: var(--fs-16);
}
/* =========================
   Loading state
   ========================= */
.btn.is-loading {
  position: relative;
  color: transparent;
  pointer-events: none;
  --btn-spinner: var(--c-text-2);
}
/* Variant-specific spinner colors */
.btn--filled.is-loading,
.btn--fab.is-loading {
  --btn-spinner: var(--c-on-primary);
}
.btn--tonal.is-loading,
.btn--text.is-loading {
  --btn-spinner: var(--c-primary);
}
.btn--outlined.is-loading {
  --btn-spinner: var(--c-text-2);
}
.btn.is-loading::after {
  content: "";
  position: absolute;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  border: 2px solid var(--btn-spinner);
  border-top-color: transparent;
  animation: btn-spin 0.8s linear infinite;
}
@keyframes btn-spin {
  to {
    transform: rotate(360deg);
  }
}