:root {
  --bg: #f4efe6;
  --surface: rgba(255, 255, 255, 0.82);
  --surface-strong: #fffdf9;
  --text: #1d2433;
  --muted: #546072;
  --primary: #005f73;
  --accent: #ee9b00;
  --border: rgba(29, 36, 51, 0.12);
  --shadow: 0 24px 60px rgba(10, 24, 35, 0.12);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Avenir Next", "Segoe UI", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at top left, rgba(238, 155, 0, 0.22), transparent 30%),
    linear-gradient(135deg, #f4efe6, #d9e7e8 52%, #edf3f4);
}

.app-shell {
  width: min(1080px, calc(100% - 32px));
  margin: 0 auto;
  padding: 48px 0 64px;
}

.hero,
.panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 24px;
  box-shadow: var(--shadow);
  backdrop-filter: blur(12px);
}

.hero {
  padding: 40px;
  margin-bottom: 24px;
}

.eyebrow {
  margin: 0 0 12px;
  text-transform: uppercase;
  letter-spacing: 0.18em;
  font-size: 0.78rem;
  color: var(--primary);
  font-weight: 700;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  max-width: 14ch;
  font-size: clamp(2.4rem, 6vw, 4.4rem);
  line-height: 0.95;
  margin-bottom: 16px;
}

.intro,
.panel-heading p,
label span,
#backend-info,
#result-output {
  color: var(--muted);
}

.panel {
  padding: 32px;
}

.calculator-form {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
  align-items: end;
  margin: 28px 0;
}

label {
  display: block;
}

label span {
  display: block;
  margin-bottom: 8px;
  font-size: 0.92rem;
  font-weight: 600;
}

input,
select,
button {
  width: 100%;
  border-radius: 14px;
  border: 1px solid var(--border);
  padding: 14px 16px;
  font: inherit;
}

input,
select {
  background: var(--surface-strong);
}

button {
  background: linear-gradient(135deg, var(--primary), #0a9396);
  color: white;
  border: 0;
  font-weight: 700;
  cursor: pointer;
  transition: transform 140ms ease, box-shadow 140ms ease;
  box-shadow: 0 14px 28px rgba(0, 95, 115, 0.22);
}

button:hover {
  transform: translateY(-1px);
}

.result-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.result-card {
  border-radius: 20px;
  border: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.72);
  padding: 20px;
}

pre {
  margin: 0;
  white-space: pre-wrap;
  word-break: break-word;
  font-family: "SFMono-Regular", "Menlo", monospace;
  font-size: 0.92rem;
}

@media (max-width: 820px) {
  .calculator-form,
  .result-grid {
    grid-template-columns: 1fr;
  }

  .app-shell {
    width: min(100% - 20px, 1080px);
    padding: 20px 0 40px;
  }

  .hero,
  .panel {
    padding: 20px;
    border-radius: 20px;
  }
}