:root {
  --bg: radial-gradient(1200px 600px at 10% 10%, #f0f4ff 0%, #ffffff 40%, #fefefe 100%);
  --calc-ar: 4 / 7;
}
html, body {
  height: 100%;
}
body {
  background: var(--bg);
}

html body {
  padding-top: 0;
}

.calc-wrap {
  aspect-ratio: var(--calc-ar);
  width: min(100vw, calc(100vh * var(--calc-ar)));
  height: auto;
}
.card, .card-body {
  height: 100%;
}
.card-body {
  display: flex;
  flex-direction: column;
}
.calc-display {
  width: 100%;
  min-height: 90px;
  padding: 16px 18px;
  border-radius: 0.5rem;
  background: #0b1220;
  color: #e9f2ff;
  font-size: 2.5rem;
  line-height: 1.2;
  text-align: right;
  overflow: hidden;
  word-wrap: break-word;
}
.calc-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  grid-template-rows: repeat(10, 1fr);
  gap: 10px;
  flex: 1;
}
.calc-grid .btn {
  width: 100%;
  height: 100%;
  padding: 0;
  font-size: 1.1rem;
  border-radius: 0.6rem;
}

.col-span-2 {
  grid-column: span 2;
}
@media (max-width: 575.98px) {
  .calc-wrap {
    width: min(100vw, calc(100vh * var(--calc-ar)));
  }
  .calc-display {
    min-height: 70px;
    font-size: 1.5rem;
  }
  .calc-grid {
    gap: 7px;
  }
  .calc-grid .btn {
    font-size: 0.95rem;
  }
}
/* Make the calculator slightly wider on medium screens while keeping height-filled behavior */
@media (min-width: 576px) and (max-width: 991.98px) {
  :root { --calc-ar: 4 / 10; }
}
/* Make the calculator wider on large screens to reduce narrowness */
@media (min-width: 992px) {
  :root { --calc-ar: 4 / 7; }
}