.btn-calculate{display:flex;align-items:center;justify-content:center;width:100%;min-height:48px;padding:clamp(.75rem,1.5vw,.875rem) clamp(1rem,2vw,1.25rem);background:var(--brand-primary);border:none;border-radius:10px;color:#fff;font-size:clamp(.8125rem,1.2vw + .1rem,.875rem);font-weight:700;box-shadow:var(--shadow-sm);cursor:pointer;transition:background-color .2s ease,box-shadow .2s ease,opacity .2s ease}.btn-calculate:hover:not(:disabled){background:var(--brand-primary-dark);box-shadow:var(--shadow-md)}.btn-calculate:active:not(:disabled){opacity:.9}.btn-calculate:disabled{opacity:.4;cursor:not-allowed;background:var(--bg-tertiary);color:var(--text-muted)}.btn-calculate .btn-loading{display:flex;align-items:center;gap:.5rem}.btn-calculate .spin{animation:spin 1s linear infinite}