/* ============================================================
   Button Component
   ============================================================ */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  font-family: var(--font-sans);
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  line-height: 1;
  border-radius: var(--radius-lg);
  border: 1px solid transparent;
  cursor: pointer;
  transition:
    background-color var(--duration-fast) var(--ease-in-out),
    color var(--duration-fast) var(--ease-in-out),
    border-color var(--duration-fast) var(--ease-in-out),
    box-shadow var(--duration-fast) var(--ease-in-out),
    transform var(--duration-fast) var(--ease-in-out),
    opacity var(--duration-fast) var(--ease-in-out);
  text-decoration: none;
  white-space: nowrap;
  user-select: none;
  position: relative;
  overflow: hidden;
}

.btn:active:not(:disabled) { transform: translateY(1px); }
.btn:disabled { opacity: 0.5; cursor: not-allowed; pointer-events: none; }

/* ── Variants ─────────────────────────────────────────────── */
.btn-primary {
  background: var(--color-primary);
  color: var(--color-primary-fg);
  box-shadow: 0 1px 3px rgba(99, 79, 230, 0.3), inset 0 1px 0 rgba(255,255,255,0.1);
}
.btn-primary:hover {
  background: var(--color-primary-hover);
  box-shadow: 0 4px 12px rgba(99, 79, 230, 0.4);
  text-decoration: none;
}

.btn-secondary {
  background: var(--color-surface);
  color: var(--color-text);
  border-color: var(--color-border);
}
.btn-secondary:hover {
  background: var(--color-surface-2);
  border-color: var(--color-text-subtle);
  text-decoration: none;
}

.btn-ghost {
  background: transparent;
  color: var(--color-text-muted);
  border-color: transparent;
}
.btn-ghost:hover {
  background: var(--color-bg-subtle);
  color: var(--color-text);
  text-decoration: none;
}

.btn-danger {
  background: var(--color-error);
  color: white;
}
.btn-danger:hover { opacity: 0.85; text-decoration: none; }

/* ── Sizes ────────────────────────────────────────────────── */
.btn-sm {
  padding: var(--space-1) var(--space-3);
  font-size: var(--text-xs);
  border-radius: var(--radius-md);
}
.btn-lg {
  padding: var(--space-3) var(--space-6);
  font-size: var(--text-base);
  border-radius: var(--radius-xl);
}
.btn-icon {
  width: 36px;
  height: 36px;
  padding: 0;
  border-radius: var(--radius-lg);
  flex-shrink: 0;
}
.btn-icon.btn-sm { width: 28px; height: 28px; border-radius: var(--radius-md); }

/* ── Loading state ────────────────────────────────────────── */
.btn-loading { pointer-events: none; }
.btn-loading::after {
  content: '';
  width: 14px;
  height: 14px;
  border: 2px solid currentColor;
  border-top-color: transparent;
  border-radius: 50%;
  animation: btn-spin 0.6s linear infinite;
}
@keyframes btn-spin { to { transform: rotate(360deg); } }