:root{font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,Microsoft YaHei,sans-serif;color:#172033;background:#dbe4ed;font-synthesis:none;text-rendering:optimizeLegibility;--desk-top: #eef3f7;--desk-bottom: #cbd7e3;--shell-top: #30373d;--shell: #191e22;--shell-edge: #111519;--lcd-top: #c9d6c2;--lcd-bottom: #aebfa9;--lcd-ink: #17251a;--lcd-muted: rgba(23, 37, 26, .58);--key-top: #596168;--key-bottom: #3a4147;--key-depth: #252b30;--utility-top: #c6cdd2;--utility-bottom: #89939a;--utility-depth: #626b72;--operator-top: #f0a04a;--operator-bottom: #d4771c;--operator-depth: #9b5012;--focus: #f6c178;--error: #6f1d14}*{box-sizing:border-box}html,body,#app{min-width:320px;min-height:100%;margin:0}body{min-height:100vh;min-height:100dvh;overflow-x:hidden;background:radial-gradient(circle at 50% -10%,#ffffffeb 0,#fff0 46%),linear-gradient(150deg,var(--desk-top),var(--desk-bottom))}button{font:inherit}.app-shell{min-height:100vh;min-height:100dvh;display:grid;place-items:center;padding:clamp(24px,6vh,64px) 20px}.calculator{width:min(100%,370px);padding:22px;border:1px solid rgba(255,255,255,.13);border-radius:30px;color:#f8fafc;background:linear-gradient(145deg,rgba(255,255,255,.08),transparent 24%),linear-gradient(160deg,var(--shell-top),var(--shell) 58%,var(--shell-edge));box-shadow:inset 1px 1px #ffffff24,inset -1px -1px #00000057,0 34px 65px #26323f47,0 11px 22px #1c242c40}.calculator-brand{display:flex;align-items:center;justify-content:space-between;margin:0 4px 13px;color:#f5f7f9a8;font-size:10px;font-weight:800;letter-spacing:.15em;line-height:1}.calculator-display{min-height:106px;display:flex;flex-direction:column;align-items:flex-end;justify-content:center;gap:5px;margin-bottom:19px;padding:14px 17px 12px;overflow:hidden;border:1px solid rgba(32,54,37,.28);border-radius:12px;color:var(--lcd-ink);background:linear-gradient(155deg,rgba(255,255,255,.24),transparent 34%),linear-gradient(155deg,var(--lcd-top),var(--lcd-bottom));box-shadow:inset 0 5px 10px #2237274f,inset 0 -1px #ffffff54,0 1px #ffffff14}.display-expression{width:100%;min-height:17px;overflow:hidden;color:var(--lcd-muted);font-family:Courier New,ui-monospace,monospace;font-size:12px;font-weight:700;line-height:1.25;text-align:right;text-overflow:ellipsis;white-space:nowrap}.display-value,.display-error{width:100%;overflow:hidden;font-family:Courier New,ui-monospace,monospace;font-size:clamp(34px,10vw,42px);font-weight:700;line-height:1.05;letter-spacing:-.07em;text-align:right;text-overflow:ellipsis;white-space:nowrap}.display-error{color:var(--error);font-family:inherit;font-size:19px;letter-spacing:-.02em}.calculator-keypad{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:12px 11px}.calculator-key{position:relative;min-width:0;min-height:58px;padding:0;border:1px solid rgba(255,255,255,.09);border-radius:13px;color:#f7fafc;background:linear-gradient(var(--key-top),var(--key-bottom));box-shadow:0 5px 0 var(--key-depth),0 8px 12px #0000002e,inset 0 1px #ffffff29;cursor:pointer;font-size:19px;font-weight:800;line-height:1;text-shadow:0 1px 1px rgba(0,0,0,.38);transform:translateY(0);transition:transform 80ms ease,box-shadow 80ms ease,filter .12s ease;-webkit-tap-highlight-color:transparent;touch-action:manipulation}.calculator-key:hover:not(:disabled){filter:brightness(1.08)}.calculator-key:active:not(:disabled),.calculator-key.is-active:not(:disabled){transform:translateY(4px);box-shadow:0 1px 0 var(--key-depth),0 3px 6px #0000002e,inset 0 1px #ffffff1c}.calculator-key:focus-visible{outline:3px solid var(--focus);outline-offset:3px}.calculator-key:disabled{cursor:wait;filter:saturate(.55) brightness(.76)}.key-utility{color:#171c20;background:linear-gradient(var(--utility-top),var(--utility-bottom));box-shadow:0 5px 0 var(--utility-depth),0 8px 12px #00000029,inset 0 1px #ffffff61;text-shadow:0 1px 0 rgba(255,255,255,.42)}.key-utility:active:not(:disabled),.key-utility.is-active:not(:disabled){box-shadow:0 1px 0 var(--utility-depth),0 3px 6px #00000029,inset 0 1px #ffffff40}.key-operator{color:#fffaf3;background:linear-gradient(var(--operator-top),var(--operator-bottom));box-shadow:0 5px 0 var(--operator-depth),0 8px 12px #0003,inset 0 1px #ffffff38}.key-operator:active:not(:disabled),.key-operator.is-active:not(:disabled){box-shadow:0 1px 0 var(--operator-depth),0 3px 6px #0000002e,inset 0 1px #ffffff2b}.key-wide-utility,.key-zero{grid-column:span 2}.backspace-icon{width:25px;height:25px;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}.visually-hidden{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}@media (max-width: 420px){.app-shell{align-items:center;padding:18px 12px calc(18px + env(safe-area-inset-bottom))}.calculator{width:min(100%,356px);padding:19px;border-radius:26px}.calculator-display{min-height:98px;margin-bottom:17px}.calculator-keypad{gap:10px 9px}.calculator-key{min-height:54px;border-radius:12px}}@media (max-height: 620px){.app-shell{padding-block:12px}.calculator{padding:17px}.calculator-display{min-height:88px;margin-bottom:14px}.calculator-key{min-height:48px}}@media (prefers-reduced-motion: reduce){.calculator-key{transition:none}}