.instrument {
  width: 100%;
  max-width: 800px;
  margin: 0 auto 50px;
  background: var(--panel);
  border: 1px solid var(--hairline);
  border-radius: var(--radius-lg);
  padding: 50px 40px;
  position: relative;
  box-shadow: var(--shadow-lg);
}

/* Corner ticks representing time instrument theme */
.instrument::before,
.instrument::after,
.tick-br,
.tick-bl {
  content: "";
  position: absolute;
  width: 16px;
  height: 16px;
  border: 1.5px solid var(--gold-dim);
  pointer-events: none;
}

.instrument::before { top: -1px; left: -1px; border-right: none; border-bottom: none; border-top-left-radius: var(--radius-lg); }
.instrument::after { top: -1px; right: -1px; border-left: none; border-bottom: none; border-top-right-radius: var(--radius-lg); }
.tick-bl { bottom: -1px; left: -1px; border-right: none; border-top: none; border-bottom-left-radius: var(--radius-lg); }
.tick-br { bottom: -1px; right: -1px; border-left: none; border-top: none; border-bottom-right-radius: var(--radius-lg); }

.eyebrow {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--gold);
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
}

.eyebrow::before {
  content: "";
  display: inline-block;
  width: 24px;
  height: 1px;
  background: var(--gold-dim);
}

h1 {
  font-family: var(--font-serif);
  font-weight: 500;
  font-size: clamp(32px, 5vw, 44px);
  line-height: 1.2;
  margin-bottom: 12px;
  letter-spacing: -0.02em;
  color: var(--ivory);
}

.subtitle {
  font-size: 15px;
  color: var(--ivory-dim);
  margin-bottom: 36px;
  max-width: 60ch;
  line-height: 1.6;
}

/* Calculator Form */
form.calc-form {
  display: flex;
  gap: 20px;
  align-items: flex-end;
  flex-wrap: wrap;
  padding-bottom: 36px;
  border-bottom: 1px solid var(--hairline);
  margin-bottom: 36px;
}

form.calc-form .field {
  flex: 1 1 220px;
}

form.calc-form button {
  flex: 0 0 auto;
}

.error {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--red);
  margin: -24px 0 24px;
  min-height: 18px;
}

/* Facts Grid */
.facts {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
  gap: 12px;
  margin-top: 24px;
}

.fact {
  background: var(--panel-light);
  border: 1px solid var(--hairline-light);
  border-radius: var(--radius-md);
  padding: 18px 20px;
  transition: border-color var(--transition-fast);
}

.fact:hover {
  border-color: var(--gold-dim);
}

.fact-label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--slate);
  margin-bottom: 8px;
}

.fact-value {
  font-family: var(--font-sans);
  font-size: 16px;
  font-weight: 600;
  color: var(--ivory);
}

/* Prose/Info Section styling */
.prose {
  margin-top: 60px;
  border-top: 1px solid var(--hairline);
  padding-top: 40px;
}

.prose h2 {
  font-family: var(--font-serif);
  font-weight: 500;
  font-size: 24px;
  color: var(--ivory);
  margin: 36px 0 16px;
}

.prose h2:first-of-type {
  margin-top: 0;
}

.prose p {
  font-size: 15px;
  line-height: 1.8;
  color: var(--ivory-dim);
  margin-bottom: 20px;
}

.prose strong {
  color: var(--ivory);
  font-weight: 600;
}

.prose ul, .prose ol {
  color: var(--ivory-dim);
  font-size: 15px;
  line-height: 1.8;
  padding-left: 24px;
  margin-bottom: 20px;
}

.prose li {
  margin-bottom: 8px;
}

.updated {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--slate);
  margin-bottom: 30px;
  display: block;
}

/* BMI specifics */
.bmi-unit-selector {
  margin-bottom: 24px;
}

.bmi-unit-selector select {
  max-width: 260px;
}

.bmi-fields-wrapper {
  display: flex;
  flex-direction: column;
  gap: 20px;
  width: 100%;
}