.nbc-calc { width: 100%; }
.nbc-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; margin-bottom: 16px; }
.nbc-input {
    width: 100%; padding: 12px 14px; border: 1px solid var(--border); border-radius: 8px;
    font-size: 16px; font-family: 'Courier New', monospace; color: var(--navy); font-weight: 600;
    background: var(--white); outline: none; box-sizing: border-box; letter-spacing: 0.5px;
}
.nbc-input:focus { border-color: var(--teal); }
.nbc-error-msg { font-size: 13px; color: #dc2626; margin: 8px 0 0; text-align: center; }
@media (max-width: 600px) { .nbc-grid { grid-template-columns: 1fr; } }