:root {
  color-scheme: dark;
  --ink: #f6f4ef;
  --muted: #a9a7b5;
  --panel: rgba(28, 27, 39, 0.86);
  --panel-border: rgba(255, 255, 255, 0.1);
  --button: #2d2c3d;
  --button-hover: #3b394d;
  --accent: #e8b86d;
  --accent-ink: #2a1b12;
}

* { box-sizing: border-box; }

body {
  min-height: 100vh;
  margin: 0;
  display: grid;
  place-items: center;
  padding: 24px;
  color: var(--ink);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background:
    radial-gradient(circle at 15% 10%, rgba(118, 98, 182, 0.25), transparent 32%),
    radial-gradient(circle at 90% 90%, rgba(232, 184, 109, 0.13), transparent 35%),
    #111019;
}

.app { width: min(100%, 420px); }

.eyebrow {
  margin: 0 0 8px;
  color: var(--accent);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

h1 {
  margin: 0 0 18px;
  font-size: clamp(2rem, 8vw, 3rem);
  letter-spacing: -0.06em;
  line-height: 0.95;
}

.calculator {
  padding: 14px;
  border: 1px solid var(--panel-border);
  border-radius: 28px;
  background: var(--panel);
  box-shadow: 0 28px 80px rgba(0, 0, 0, 0.38), inset 0 1px rgba(255, 255, 255, 0.06);
  backdrop-filter: blur(18px);
}

.display {
  min-height: 132px;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  align-items: flex-end;
  gap: 10px;
  padding: 22px 18px;
  overflow: hidden;
  border-radius: 19px;
  background: rgba(11, 10, 17, 0.72);
}

.expression {
  width: 100%;
  min-height: 22px;
  overflow: hidden;
  color: var(--muted);
  font-size: 0.95rem;
  text-align: right;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.result {
  width: 100%;
  overflow: hidden;
  font-size: clamp(2.3rem, 12vw, 4rem);
  font-weight: 700;
  letter-spacing: -0.07em;
  text-align: right;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.keypad {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
  margin-top: 14px;
}

button {
  min-height: 62px;
  border: 0;
  border-radius: 17px;
  color: var(--ink);
  background: var(--button);
  font: inherit;
  font-size: 1.15rem;
  font-weight: 650;
  cursor: pointer;
  transition: transform 0.15s ease, background 0.15s ease, box-shadow 0.15s ease;
}

button:hover { background: var(--button-hover); }
button:active { transform: scale(0.95); }
button:focus-visible {
  outline: 3px solid rgba(232, 184, 109, 0.55);
  outline-offset: 2px;
}

.operator {
  color: var(--accent);
  background: rgba(111, 88, 149, 0.3);
}

.operator:hover { background: rgba(126, 99, 169, 0.42); }
.utility {
  color: #d2cedf;
  background: rgba(255, 255, 255, 0.08);
}

.equals {
  color: var(--accent-ink);
  background: var(--accent);
  box-shadow: 0 8px 24px rgba(232, 184, 109, 0.22);
}

.equals:hover { background: #f1c57d; }
.span-two { grid-column: span 2; }

.hint {
  margin: 16px 0 0;
  color: var(--muted);
  font-size: 0.78rem;
  text-align: center;
}

@media (max-width: 380px) {
  body { padding: 16px; }
  button { min-height: 56px; }
  .calculator { padding: 11px; }
}