/* Buttons — all 8 states */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  height: 40px;
  padding: 0 var(--space-5);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-paper-0);
  color: var(--color-ink-0);
  font-family: var(--font-ui);
  font-size: 14px;
  font-weight: 600;
  white-space: nowrap;
  cursor: pointer;
  transition: background var(--duration-fast) ease,
              border-color var(--duration-fast) ease,
              transform var(--duration-fast) ease,
              opacity var(--duration-fast) ease;
}

.btn svg { width: 16px; height: 16px; flex-shrink: 0; }

.btn:hover { background: var(--color-paper-2); border-color: var(--color-border-hover); }

.btn:focus-visible { outline: 2px solid var(--color-border-focus); outline-offset: 2px; }

.btn:active { transform: scale(0.97); }

.btn:disabled { opacity: 0.45; cursor: not-allowed; transform: none; }

.btn[data-state="loading"] { pointer-events: none; opacity: 0.7; }
.btn[data-state="loading"]::before {
  content: "";
  width: 14px; height: 14px;
  border: 2px solid currentColor;
  border-top-color: transparent;
  border-radius: 50%;
  animation: btn-spin 700ms linear infinite;
}
@keyframes btn-spin { to { transform: rotate(360deg); } }

.btn[data-state="error"] { border-color: var(--color-danger); color: var(--color-danger); animation: btn-shake 300ms var(--ease-out); }
.btn[data-state="success"] { border-color: var(--color-success); color: var(--color-success); }

@keyframes btn-shake {
  25% { transform: translateX(-3px); }
  75% { transform: translateX(3px); }
}

/* Variants */
.btn-primary {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: #fff;
}
.btn-primary:hover { background: var(--color-accent-hover); border-color: var(--color-accent-hover); }
.btn-primary:focus-visible { outline-offset: 3px; }

.btn-danger { color: var(--color-danger); }
.btn-danger:hover { background: var(--color-danger-dim); border-color: var(--color-danger); }

.btn-sm { height: 32px; padding: 0 var(--space-3); font-size: 13px; }
.btn-sm svg { width: 14px; height: 14px; }

.btn-icon { width: 40px; padding: 0; }
.btn-icon.btn-sm { width: 32px; }

.btn-row { display: flex; flex-wrap: wrap; gap: var(--space-2); margin-top: var(--space-4); }