:root {
  color-scheme: light;
  --ink: #10201b;
  --muted: #5e6b66;
  --panel: rgba(255, 252, 241, 0.9);
  --panel-strong: #fff9e8;
  --line: rgba(16, 32, 27, 0.16);
  --key: #f3ead2;
  --key-hover: #fff4d8;
  --operator: #164d3f;
  --operator-hover: #1e6755;
  --accent: #e36f3d;
  --accent-hover: #f08049;
  --shadow: 0 24px 70px rgba(16, 32, 27, 0.24);
}

* {
  box-sizing: border-box;
}

body {
  min-height: 100vh;
  margin: 0;
  font-family: Georgia, "Times New Roman", serif;
  color: var(--ink);
  background:
    radial-gradient(circle at 16% 18%, rgba(227, 111, 61, 0.28), transparent 28rem),
    radial-gradient(circle at 84% 10%, rgba(22, 77, 63, 0.3), transparent 24rem),
    linear-gradient(135deg, #efe1bf 0%, #d6e0cd 50%, #edc9a7 100%);
}

button {
  font: inherit;
}

.app-shell {
  display: grid;
  min-height: 100vh;
  place-items: center;
  padding: clamp(1rem, 4vw, 3rem);
}

.calculator {
  width: min(100%, 26rem);
  padding: clamp(1rem, 4vw, 1.5rem);
  border: 1px solid var(--line);
  border-radius: 2rem;
  background: var(--panel);
  box-shadow: var(--shadow);
  backdrop-filter: blur(18px);
}

.calculator__header {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1rem;
}

.eyebrow {
  margin: 0;
  color: var(--muted);
  font-family: "Trebuchet MS", Verdana, sans-serif;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

h1 {
  margin: 0;
  font-size: clamp(2.25rem, 9vw, 4rem);
  line-height: 0.9;
}

.display {
  display: block;
  width: 100%;
  min-height: 5.75rem;
  margin-bottom: 1rem;
  overflow: hidden;
  padding: 1rem;
  border: 1px solid var(--line);
  border-radius: 1.25rem;
  background: var(--panel-strong);
  font-family: "Trebuchet MS", Verdana, sans-serif;
  font-size: clamp(2.25rem, 11vw, 4.5rem);
  font-weight: 800;
  line-height: 1;
  text-align: right;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.keypad {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.7rem;
}

.key {
  min-height: clamp(3.4rem, 14vw, 4.5rem);
  border: 0;
  border-radius: 1rem;
  color: var(--ink);
  background: var(--key);
  box-shadow: inset 0 -0.18rem rgba(16, 32, 27, 0.14);
  cursor: pointer;
  font-family: "Trebuchet MS", Verdana, sans-serif;
  font-size: clamp(1.25rem, 5vw, 1.75rem);
  font-weight: 800;
  transition: transform 150ms ease, background 150ms ease, box-shadow 150ms ease;
}

.key:hover {
  background: var(--key-hover);
  transform: translateY(-1px);
}

.key:active {
  box-shadow: inset 0 0.08rem rgba(16, 32, 27, 0.18);
  transform: translateY(1px);
}

.key:focus-visible {
  outline: 3px solid rgba(227, 111, 61, 0.55);
  outline-offset: 3px;
}

.key--operator,
.key--utility {
  color: #fffaf0;
  background: var(--operator);
}

.key--operator:hover,
.key--utility:hover {
  background: var(--operator-hover);
}

.key--equals {
  grid-row: span 2;
  color: #fffaf0;
  background: var(--accent);
}

.key--equals:hover {
  background: var(--accent-hover);
}

.key--zero {
  grid-column: span 2;
}

.support-card {
  display: grid;
  gap: 0.85rem;
  margin-top: 1rem;
  padding: 1rem;
  border: 1px solid rgba(227, 111, 61, 0.36);
  border-radius: 1.35rem;
  background:
    linear-gradient(135deg, rgba(255, 249, 232, 0.96), rgba(243, 234, 210, 0.72)),
    radial-gradient(circle at top right, rgba(227, 111, 61, 0.22), transparent 9rem);
}

.support-card__eyebrow {
  margin: 0 0 0.3rem;
  color: var(--operator);
  font-family: "Trebuchet MS", Verdana, sans-serif;
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.support-card__title {
  margin: 0;
  font-size: clamp(1.45rem, 6vw, 2rem);
  line-height: 1;
}

.support-card__copy {
  margin: 0.45rem 0 0;
  color: var(--muted);
  font-family: "Trebuchet MS", Verdana, sans-serif;
  font-size: 0.95rem;
  line-height: 1.4;
}

.support-card__button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 3.2rem;
  padding: 0.85rem 1rem;
  border-radius: 999px;
  color: #fffaf0;
  background: var(--accent);
  box-shadow: inset 0 -0.18rem rgba(16, 32, 27, 0.18);
  font-family: "Trebuchet MS", Verdana, sans-serif;
  font-weight: 800;
  text-align: center;
  text-decoration: none;
  transition: transform 150ms ease, background 150ms ease, box-shadow 150ms ease;
}

.support-card__button:hover {
  background: var(--accent-hover);
  transform: translateY(-1px);
}

.support-card__button:active {
  box-shadow: inset 0 0.08rem rgba(16, 32, 27, 0.18);
  transform: translateY(1px);
}

.support-card__button:focus-visible {
  outline: 3px solid rgba(22, 77, 63, 0.45);
  outline-offset: 3px;
}

@media (max-width: 28rem) {
  .calculator__header {
    display: block;
  }

  .eyebrow {
    margin-bottom: 0.3rem;
  }

  .keypad {
    gap: 0.5rem;
  }
}