:root {
  color-scheme: light;
  --navy: #123b5d;
  --blue: #1d6fa3;
  --cyan: #0f96a8;
  --ink: #162632;
  --muted: #5c6d79;
  --line: #d9e3ea;
  --soft: #f3f7fa;
  --white: #ffffff;
  --warning: #fff5d9;
  --warning-border: #e9b949;
  --danger: #fff0ef;
  --danger-border: #d9534f;
  --green: #137a52;
  --green-soft: #eaf8f1;
  --red: #b4232c;
  --red-soft: #fff0f1;
  --purple: #7654a6;
  --shadow: 0 18px 50px rgba(18, 59, 93, 0.1);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: linear-gradient(180deg, #eef6fa 0, #ffffff 34rem);
  color: var(--ink);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.55;
}

.site-header, main, footer { width: min(1080px, calc(100% - 2rem)); margin-inline: auto; }

.site-header {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  padding: 3rem 0 2rem;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 76px;
  height: 76px;
  border-radius: 20px;
  background: var(--navy);
  color: white;
  font-size: 0.86rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  box-shadow: var(--shadow);
}

h1, h2, h3, p { margin-top: 0; }
h1 { max-width: 800px; margin-bottom: 0.35rem; color: var(--navy); font-size: clamp(1.85rem, 4vw, 3rem); line-height: 1.08; }
h2 { margin-bottom: 0.35rem; color: var(--navy); font-size: clamp(1.3rem, 3vw, 1.85rem); }
h3 { margin-bottom: 0.2rem; }
.eyebrow, .step-label { margin-bottom: 0.35rem; color: var(--blue); font-size: 0.75rem; font-weight: 800; letter-spacing: 0.1em; text-transform: uppercase; }
.subtitle { margin-bottom: 0; color: var(--muted); }

main { display: grid; gap: 1.5rem; }
.calculator-tabs { display: grid; grid-template-columns: 1fr 1fr; gap: 0.45rem; border: 1px solid var(--line); border-radius: 17px; background: #e8f0f5; padding: 0.4rem; }
.tab-button { border: 0; border-radius: 12px; background: transparent; color: var(--muted); cursor: pointer; font: inherit; font-weight: 800; padding: 0.8rem 1rem; }
.tab-button.active { background: var(--white); color: var(--navy); box-shadow: 0 4px 14px rgba(18,59,93,0.12); }
.tab-button:focus-visible { outline: 3px solid rgba(29,111,163,0.25); }
.hypertension-panel { display: grid; gap: 1.5rem; }
.tab-panel-hidden { display: none !important; }
[hidden] { display: none !important; }
.calculator-card, .results, .evidence-card {
  border: 1px solid rgba(217, 227, 234, 0.9);
  border-radius: 24px;
  background: rgba(255, 255, 255, 0.96);
  box-shadow: var(--shadow);
  padding: clamp(1.25rem, 4vw, 2.25rem);
}

.section-heading, .age-result { display: flex; align-items: center; justify-content: space-between; gap: 1rem; }
.text-button { border: 0; background: none; color: var(--blue); font: inherit; font-weight: 700; cursor: pointer; }

form { display: grid; gap: 1.25rem; margin-top: 1.5rem; }
fieldset { min-width: 0; margin: 0; border: 0; padding: 0; }
legend { margin-bottom: 0.65rem; font-weight: 750; }
.input-row { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 1rem; max-width: 620px; }
.bp-input-row { grid-template-columns: repeat(3, minmax(0, 1fr)); max-width: 820px; }
.patient-bp-fieldset { border-top: 1px solid var(--line); padding-top: 1.15rem; }
.optional-label { border-radius: 999px; background: var(--soft); color: var(--muted); font-size: 0.7rem; font-weight: 700; padding: 0.25rem 0.5rem; vertical-align: middle; }
.field-help { margin: -0.3rem 0 0.75rem; color: var(--muted); font-size: 0.82rem; }
.input-row label, .select-label { display: grid; gap: 0.4rem; color: var(--muted); font-size: 0.88rem; font-weight: 650; }
.select-label { max-width: 620px; }
.reference-model-tabs { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 0.65rem; max-width: 820px; }
.reference-model-tab {
  min-width: 0;
  border: 1px solid #b9cbd7;
  border-radius: 14px;
  background: var(--white);
  color: var(--navy);
  cursor: pointer;
  font: inherit;
  padding: 0.9rem 1rem;
  text-align: left;
}
.reference-model-tab span { display: block; font-weight: 800; }
.reference-model-tab small { display: block; margin-top: 0.2rem; color: var(--muted); font-size: 0.74rem; line-height: 1.35; }
.reference-model-tab.active { border-color: var(--blue); background: #eef7fd; box-shadow: 0 0 0 2px rgba(29, 111, 163, 0.14); }
.reference-model-tab.active::after { content: "Selected"; display: inline-block; margin-top: 0.45rem; border-radius: 999px; background: var(--navy); color: white; font-size: 0.66rem; font-weight: 800; padding: 0.18rem 0.48rem; }
.reference-model-tab:focus-visible { outline: 3px solid rgba(29, 111, 163, 0.22); outline-offset: 2px; }
.other-reference-label { margin-top: 0.85rem; }
.other-reference-label select.active { border-color: var(--blue); background: #eef7fd; box-shadow: 0 0 0 2px rgba(29, 111, 163, 0.14); }
input, select {
  width: 100%;
  border: 1px solid #b9cbd7;
  border-radius: 12px;
  background: white;
  color: var(--ink);
  font: inherit;
  font-size: 1.05rem;
  padding: 0.78rem 0.9rem;
}
input:focus, select:focus { outline: 3px solid rgba(29, 111, 163, 0.18); border-color: var(--blue); }
.primary-button {
  width: fit-content;
  border: 0;
  border-radius: 13px;
  background: var(--navy);
  color: white;
  cursor: pointer;
  font: inherit;
  font-weight: 750;
  padding: 0.85rem 1.3rem;
}
.primary-button:hover { background: #0c2d48; }
.error-message { margin: 0; color: #a32622; font-weight: 650; }

.results { display: grid; gap: 1.4rem; scroll-margin-top: 1rem; }
.age-result { border-bottom: 1px solid var(--line); padding-bottom: 1.2rem; }
.cga-display { margin: 0; color: var(--navy); font-size: 1.35rem; white-space: nowrap; }
.cga-display strong { font-size: 1.85rem; }
.warning { border-left: 5px solid var(--warning-border); border-radius: 10px; background: var(--warning); padding: 1rem 1.1rem; }
.warning.danger { border-color: var(--danger-border); background: var(--danger); }
.method-badge { border-radius: 999px; background: #e5f4f6; color: #0a6572; font-size: 0.78rem; font-weight: 750; padding: 0.4rem 0.7rem; }
.contemporary-badge { background: #e8f6ee; color: #17663a; }
.bp-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1rem; margin-top: 1.2rem; }
.bp-card { overflow: hidden; position: relative; border: 1px solid var(--line); border-radius: 18px; padding: 1.2rem; }
.bp-card::before { content: ""; position: absolute; inset: 0 0 auto; height: 5px; background: var(--blue); }
.bp-card.dbp::before { background: var(--cyan); }
.bp-card.map::before { background: var(--navy); }
.abbreviation { color: var(--muted); font-size: 0.82rem; }
dl { margin: 1rem 0 0; }
dl div { display: flex; align-items: baseline; justify-content: space-between; gap: 0.5rem; border-top: 1px solid var(--line); border-radius: 8px; padding: 0.65rem 0.5rem; }
.centile-0 { background: #fff3f3; border-left: 4px solid var(--red); }
.centile-0 dt, .centile-0 dd strong { color: var(--red); }
.centile-1 { background: #eef7fd; border-left: 4px solid var(--blue); }
.centile-1 dt, .centile-1 dd strong { color: var(--blue); }
.centile-2 { background: #f5f1fb; border-left: 4px solid var(--purple); }
.centile-2 dt, .centile-2 dd strong { color: var(--purple); }
.htn-centile-0 { background: #eef7fd; border-left: 4px solid var(--blue); }
.htn-centile-0 dt, .htn-centile-0 dd strong { color: var(--blue); }
.htn-centile-1 { background: #fff7e8; border-left: 4px solid #c26a00; }
.htn-centile-1 dt, .htn-centile-1 dd strong { color: #9a5300; }
.htn-centile-2 { background: var(--red-soft); border-left: 4px solid var(--red); }
.htn-centile-2 dt, .htn-centile-2 dd strong { color: var(--red); }
dt { color: var(--muted); font-size: 0.84rem; }
dd { margin: 0; }
dd strong { color: var(--navy); font-size: 1.35rem; }
dd span { color: var(--muted); font-size: 0.72rem; }
.fine-print { margin: 0.8rem 0 0; color: var(--muted); font-size: 0.8rem; }
.model-note { margin: 1rem 0 0; border-radius: 10px; background: var(--soft); color: #344d5d; font-size: 0.84rem; padding: 0.8rem 0.9rem; }
.patient-comparison { margin-top: 1.4rem; border-top: 1px solid var(--line); padding-top: 1.3rem; }
.comparison-heading { display: flex; align-items: center; justify-content: space-between; gap: 1rem; }
.comparison-heading h3 { color: var(--navy); font-size: 1.2rem; }
.comparison-rule { border-radius: 999px; background: var(--red-soft); color: var(--red); font-size: 0.75rem; font-weight: 750; padding: 0.4rem 0.7rem; }
.comparison-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 0.85rem; margin-top: 1rem; }
.comparison-card { display: flex; gap: 0.8rem; border: 1px solid; border-radius: 16px; padding: 1rem; }
.comparison-card.low { border-color: #efb8bc; background: var(--red-soft); color: var(--red); }
.comparison-card.acceptable { border-color: #a8d9c1; background: var(--green-soft); color: var(--green); }
.comparison-card.high { border-color: #efce96; background: #fff7e8; color: #9a5300; }
.comparison-card.below-95 { border-color: #a8d9c1; background: var(--green-soft); color: var(--green); }
.comparison-card.elevated { border-color: #efce96; background: #fff7e8; color: #9a5300; }
.comparison-card.markedly-elevated { border-color: #efb8bc; background: var(--red-soft); color: var(--red); }
.status-icon { display: grid; place-items: center; flex: 0 0 auto; width: 34px; height: 34px; border-radius: 50%; background: currentColor; color: white; font-weight: 900; }
.comparison-name, .comparison-value, .comparison-status, .comparison-threshold { margin: 0; }
.comparison-name { color: var(--ink); font-size: 0.8rem; font-weight: 700; }
.comparison-value strong { font-size: 1.45rem; }
.comparison-status { font-size: 1.05rem; font-weight: 850; }
.comparison-threshold { color: var(--muted); font-size: 0.76rem; }
.comparison-caution { margin: 0.9rem 0 0; color: var(--muted); font-size: 0.8rem; }
.htn-intro { margin: 0.35rem 0 0; }
.htn-button { background: #8f3f18; }
.htn-button:hover { background: #6f2f11; }
.htn-badge { background: #fff0e6; color: #8f3f18; }
.htn-rule { background: #fff7e8; color: #8f3f18; }
.htn-evidence > p { color: var(--muted); margin-bottom: 0; }

.evidence-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 1.5rem; margin-top: 1rem; }
.evidence-grid p { margin-bottom: 0; color: var(--muted); }
details { margin-top: 1.4rem; border-top: 1px solid var(--line); padding-top: 1rem; }
summary { color: var(--blue); cursor: pointer; font-weight: 750; }
.details-content { margin-top: 1rem; color: #374b59; }
.details-content li { margin-bottom: 0.55rem; }
footer { padding: 1.5rem 0 3rem; color: var(--muted); font-size: 0.82rem; text-align: center; }

@media (max-width: 720px) {
  .site-header { align-items: flex-start; padding-top: 1.6rem; }
  .brand-mark { width: 58px; height: 58px; border-radius: 15px; flex: 0 0 auto; }
  .bp-grid, .evidence-grid, .comparison-grid { grid-template-columns: 1fr; }
  .bp-input-row { grid-template-columns: 1fr; }
  .age-result, .section-heading { align-items: flex-start; }
  .age-result { flex-direction: column; }
  .cga-display { white-space: normal; }
}

@media (max-width: 460px) {
  .site-header { gap: 0.8rem; }
  .eyebrow { display: none; }
  .input-row { grid-template-columns: 1fr; }
  .reference-model-tab { padding: 0.75rem; }
  .reference-model-tab small { font-size: 0.68rem; }
  .method-badge { display: none; }
}

@media print {
  body { background: white; }
  .calculator-card, .evidence-card, footer, .text-button { display: none; }
  .results { box-shadow: none; border: 0; }
}