:root{font-family:system-ui,sans-serif;color-scheme:light}body{margin:0;background:#f5f5f5;color:#1a1a1a}.nav-bar{display:flex;gap:1rem;padding:1rem 1.5rem;background:#fff;border-bottom:1px solid #e0e0e0}.nav-link{text-decoration:none;color:#444;font-weight:500}.nav-link--active{color:#1a1a1a;text-decoration:underline}.page{display:flex;justify-content:center;padding:2rem 1rem}.calculator{display:flex;flex-direction:column;gap:.5rem;width:100%;max-width:320px;background:#fff;padding:1.5rem;border-radius:8px;border:1px solid #e0e0e0}.calculator h1{font-size:1.25rem;margin:0 0 .5rem}.calculator input{padding:.5rem;font-size:1rem;border:1px solid #ccc;border-radius:4px}.calculator button{margin-top:.5rem;padding:.5rem;font-size:1rem;border:none;border-radius:4px;background:#2563eb;color:#fff;cursor:pointer}.calculator button:hover{background:#1d4ed8}.message{margin:.25rem 0 0;font-size:.95rem}.message--error{color:#b91c1c}.message--result{color:#15803d;font-weight:600}