*{box-sizing:border-box}
html,body{margin:0;height:100%}
body{background:#075071;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Arial,sans-serif}
.calc{max-width:460px;margin:0 auto;height:100dvh;display:flex;flex-direction:column;padding:14px;gap:10px}
.calc-display{flex:0 0 auto;min-height:120px;display:flex;align-items:flex-end;justify-content:flex-end;color:#fff;font-size:56px;font-weight:600;padding:20px 12px;overflow:hidden;white-space:nowrap}
.calc-grid{flex:1 1 auto;display:grid;grid-template-columns:repeat(4,1fr);grid-auto-rows:1fr;gap:10px}
.calc-key{border:0;border-radius:16px;font-size:26px;font-weight:700;color:#102a38;background:#f5f9fb;cursor:pointer;-webkit-tap-highlight-color:transparent;user-select:none}
.calc-key:active{filter:brightness(.92)}
.calc-key.op{background:#f28c28;color:#fff}
.calc-key.fn{background:#2a82a8;color:#fff}