.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  border: 2px solid transparent;
  border-radius: var(--radius-md);
  font-family: var(--font-base);
  font-size: var(--text-base);
  font-weight: 600;
  line-height: 1;
  cursor: pointer;
  text-decoration: none;
  transition: background var(--transition), color var(--transition),
              border-color var(--transition), opacity var(--transition);
  white-space: nowrap;
  user-select: none;
}

.btn:disabled {
  opacity: .5;
  cursor: not-allowed;
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}
.btn-primary:hover:not(:disabled) { background: var(--color-primary-dark); border-color: var(--color-primary-dark); }

.btn-outline {
  background: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}
.btn-outline:hover:not(:disabled) { background: var(--color-primary); color: #fff; }

.btn-ghost {
  background: var(--color-bg);
  color: var(--color-neutral);
  border-color: var(--color-border);
}
.btn-ghost:hover:not(:disabled) { background: #dee2e6; }

.btn-danger {
  background: var(--color-danger);
  color: #fff;
  border-color: var(--color-danger);
}
.btn-danger:hover:not(:disabled) { background: var(--color-primary-dark); }

.btn-success {
  background: var(--color-success);
  color: #fff;
  border-color: var(--color-success);
}
.btn-success:hover:not(:disabled) { background: #1e8449; }

.btn-sm {
  padding: var(--space-2) var(--space-4);
  font-size: var(--text-sm);
}

.btn-full { width: 100%; }

.btn-icon {
  padding: var(--space-2);
  border-radius: var(--radius-sm);
}

/* Loading spinner w przycisku */
.btn.loading { pointer-events: none; opacity: .75; }
.btn.loading::after {
  content: '';
  width: 1em; height: 1em;
  border: 2px solid currentColor;
  border-top-color: transparent;
  border-radius: 50%;
  animation: spin .6s linear infinite;
  margin-left: var(--space-2);
}

@keyframes spin { to { transform: rotate(360deg); } }