/* CalculateZScore — mobile-first stylesheet. System fonts only, no frameworks. */
:root{
  --navy:#0f2a4a; --navy-2:#14365e; --blue:#2563eb; --blue-dark:#1d4ed8;
  --sky:#eff6ff; --sky-2:#dbeafe; --ink:#1e293b; --muted:#5b6b82;
  --line:#e2e8f0; --bg:#ffffff; --bg-soft:#f8fafc;
  --green:#15803d; --red:#b91c1c; --amber:#b45309;
  --radius:12px; --shadow:0 6px 24px rgba(15,42,74,.08);
  --font:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;font-family:var(--font);color:var(--ink);background:var(--bg);
  font-size:1.0625rem;line-height:1.7;-webkit-text-size-adjust:100%}
img{max-width:100%;height:auto}
a{color:var(--blue);text-decoration:underline;text-underline-offset:2px}
a:hover{color:var(--blue-dark)}
:focus-visible{outline:3px solid var(--blue);outline-offset:2px;border-radius:4px}
.wrap{max-width:1080px;margin:0 auto;padding:0 1.1rem}
main{display:block;padding-bottom:3rem}
h1,h2,h3{line-height:1.25;color:var(--navy);letter-spacing:-.01em}
h1{font-size:2rem;margin:1.4rem 0 .6rem}
h2{font-size:1.45rem;margin:2.4rem 0 .7rem;padding-top:.4rem;border-top:1px solid var(--line)}
h2:first-of-type{border-top:0;padding-top:0}
h3{font-size:1.15rem;margin:1.6rem 0 .4rem}
p{margin:.7rem 0}
ul,ol{margin:.7rem 0;padding-left:1.4rem}
li{margin:.35rem 0}
.lede{font-size:1.2rem;color:var(--muted);margin:.4rem 0 1.4rem}
code,kbd{font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  background:var(--bg-soft);border:1px solid var(--line);border-radius:6px;padding:.1em .4em;font-size:.92em}

/* ---------- header ---------- */
.site-header{background:var(--navy);color:#fff;position:sticky;top:0;z-index:50;
  box-shadow:0 2px 10px rgba(0,0,0,.18)}
.header-inner{display:flex;align-items:center;justify-content:space-between;gap:.8rem;
  padding-top:.65rem;padding-bottom:.65rem}
.brand{display:flex;align-items:center;gap:.55rem;color:#fff;text-decoration:none;font-weight:800;
  font-size:1.2rem;letter-spacing:-.01em}
.brand em{font-style:normal;color:#93c5fd}
.brand svg{flex:0 0 auto}
.nav-toggle{display:inline-flex;align-items:center;justify-content:center;width:44px;height:44px;
  background:transparent;border:1px solid rgba(255,255,255,.35);border-radius:8px;color:#fff;cursor:pointer}
.nav-toggle svg{width:22px;height:22px}
#site-nav{display:none}
#site-nav.open{display:block}
#site-nav ul{list-style:none;margin:.6rem 0 0;padding:0;display:flex;flex-direction:column;gap:.1rem}
#site-nav a{display:block;color:#e2e8f0;text-decoration:none;padding:.65rem .4rem;border-radius:8px;font-weight:600}
#site-nav a:hover{background:rgba(255,255,255,.1);color:#fff}
#site-nav a[aria-current="page"]{background:rgba(255,255,255,.14);color:#fff}
@media(min-width:860px){
  .nav-toggle{display:none}
  #site-nav{display:block}
  #site-nav ul{flex-direction:row;gap:.2rem;margin:0;flex-wrap:wrap}
  #site-nav a{padding:.5rem .65rem;font-size:.98rem}
}

/* ---------- breadcrumbs ---------- */
.crumbs{font-size:.9rem;color:var(--muted);margin:1rem 0 0}
.crumbs a{color:var(--muted)}
.crumbs ol{list-style:none;display:flex;flex-wrap:wrap;gap:.4rem;margin:0;padding:0}
.crumbs li{margin:0}
.crumbs li+li::before{content:"›";margin-right:.4rem;color:#94a3b8}

/* ---------- tool card ---------- */
.tool-card{background:#fff;border:1px solid var(--line);border-radius:var(--radius);
  box-shadow:var(--shadow);padding:1.2rem;margin:1.2rem 0 1.6rem}
.tool-card h2{border:0;margin:0 0 .9rem;padding:0;font-size:1.3rem}
.tabs{display:flex;flex-wrap:wrap;gap:.5rem;margin-bottom:1.1rem}
.tab-btn{border:1px solid var(--line);background:var(--bg-soft);color:var(--ink);
  border-radius:999px;padding:.55rem 1rem;font:inherit;font-weight:700;cursor:pointer}
.tab-btn:hover{border-color:var(--blue)}
.tab-btn[aria-selected="true"]{background:var(--blue);border-color:var(--blue);color:#fff}
.tab-panel{display:none}
.tab-panel.active{display:block}
.field-grid{display:grid;grid-template-columns:1fr;gap:.9rem;margin-bottom:1rem}
@media(min-width:640px){.field-grid{grid-template-columns:repeat(3,1fr)}}
.field label{display:block;font-weight:700;margin-bottom:.3rem;font-size:.98rem}
.field .sym{color:var(--muted);font-weight:400}
.field input,.field select{width:100%;font:inherit;padding:.65rem .8rem;border:1.5px solid #cbd5e1;
  border-radius:8px;background:#fff;color:var(--ink)}
.field input:focus,.field select:focus{border-color:var(--blue);outline:2px solid var(--sky-2)}
.field .hint{font-size:.85rem;color:var(--muted);margin-top:.25rem}
.field-error{color:var(--red);font-size:.92rem;font-weight:600;margin:.2rem 0 .6rem;min-height:1.2em}
.results{display:grid;grid-template-columns:1fr 1fr;gap:.7rem;margin:1rem 0}
@media(min-width:640px){.results{grid-template-columns:repeat(4,1fr)}}
.result{background:var(--sky);border:1px solid var(--sky-2);border-radius:10px;padding:.7rem .9rem}
.result .k{font-size:.82rem;color:var(--muted);font-weight:700;text-transform:uppercase;letter-spacing:.04em}
.result .v{font-size:1.35rem;font-weight:800;color:var(--navy);font-variant-numeric:tabular-nums}
.interp{background:#f0fdf4;border:1px solid #bbf7d0;border-radius:10px;padding:.8rem 1rem;margin:.8rem 0;
  color:#14532d}
.steps{background:var(--navy);color:#e2e8f0;border-radius:10px;padding:1rem 1.1rem;margin:1rem 0;
  font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;font-size:.95rem;line-height:1.8;
  overflow-x:auto;white-space:pre-wrap}
.steps .hl{color:#93c5fd;font-weight:700}
.tool-actions{display:flex;flex-wrap:wrap;gap:.6rem;margin:.8rem 0}
.btn{display:inline-block;border:0;border-radius:8px;padding:.65rem 1.15rem;font:inherit;font-weight:700;
  cursor:pointer;text-decoration:none}
.btn-primary{background:var(--blue);color:#fff}
.btn-primary:hover{background:var(--blue-dark);color:#fff}
.btn-ghost{background:#fff;color:var(--blue);border:1.5px solid var(--blue)}
.btn-ghost:hover{background:var(--sky)}
.microcopy{font-size:.88rem;color:var(--muted);margin-top:.8rem}
.curve-wrap{margin:1rem 0}
.curve-wrap canvas{width:100%;height:auto;display:block;border:1px solid var(--line);border-radius:10px;background:#fff}
.curve-cap{font-size:.85rem;color:var(--muted);text-align:center;margin-top:.35rem}

/* ---------- content blocks ---------- */
.formula-hero{background:var(--sky);border:1px solid var(--sky-2);border-radius:var(--radius);
  text-align:center;padding:1.4rem 1rem;margin:1.2rem 0;font-size:1.7rem;font-weight:800;color:var(--navy)}
.def-block{background:var(--bg-soft);border-left:4px solid var(--blue);border-radius:0 10px 10px 0;
  padding:1rem 1.2rem;margin:1.4rem 0}
.notice{background:#fffbeb;border:1px solid #fde68a;border-radius:10px;padding:.9rem 1.1rem;margin:1.2rem 0}
.notice strong{color:var(--amber)}
.notice.medical{background:#fef2f2;border-color:#fecaca}
.notice.medical strong{color:var(--red)}
table.data{width:100%;border-collapse:collapse;margin:1rem 0;font-size:.98rem;display:block;overflow-x:auto}
table.data caption{text-align:left;font-weight:700;color:var(--navy);padding-bottom:.4rem}
table.data th,table.data td{border:1px solid var(--line);padding:.55rem .7rem;text-align:left;white-space:nowrap}
table.data thead th{background:var(--navy);color:#fff;white-space:normal}
table.data tbody tr:nth-child(even){background:var(--bg-soft)}
table.data td.num,table.data th.num{text-align:right;font-variant-numeric:tabular-nums}
figure.content-img{margin:1.6rem 0}
figure.content-img img{border-radius:var(--radius);box-shadow:var(--shadow);display:block}
figure.content-img figcaption{font-size:.88rem;color:var(--muted);text-align:center;margin-top:.4rem}

/* z-table */
.ztable-tools{display:flex;flex-wrap:wrap;gap:.8rem;align-items:end;margin:1rem 0}
#ztable{font-size:.85rem}
#ztable td{cursor:pointer;min-width:3.4rem}
#ztable td.sel{background:var(--blue);color:#fff;font-weight:800}
#ztable td.rowh,#ztable th{background:var(--navy);color:#fff;cursor:default;font-weight:700}
.ztable-readout{background:var(--sky);border:1px solid var(--sky-2);border-radius:10px;
  padding:.8rem 1rem;margin:.8rem 0;font-weight:600}

/* practice reveal */
.reveal{border:1px solid var(--line);border-radius:10px;padding:1rem;margin:1rem 0;background:var(--bg-soft)}
.reveal[hidden]{display:none}

/* ---------- share ---------- */
.share-wrap{display:flex;flex-wrap:wrap;align-items:center;gap:.5rem;margin:1.6rem 0;
  padding:.9rem 1rem;background:var(--bg-soft);border:1px solid var(--line);border-radius:10px}
.share-label{font-weight:700;color:var(--navy);margin-right:.3rem}
.share-btn{display:inline-flex;align-items:center;gap:.35rem;border:1px solid var(--line);
  background:#fff;border-radius:999px;padding:.4rem .85rem;font-size:.9rem;font-weight:700;
  color:var(--ink);text-decoration:none;cursor:pointer;font-family:inherit}
.share-btn:hover{border-color:var(--blue);color:var(--blue)}
.share-btn svg{width:15px;height:15px}

/* ---------- related cards ---------- */
.rel-grid{display:grid;grid-template-columns:1fr;gap:.9rem;margin:1.2rem 0}
@media(min-width:640px){.rel-grid{grid-template-columns:1fr 1fr}}
@media(min-width:960px){.rel-grid{grid-template-columns:1fr 1fr 1fr}}
.rel-card{border:1px solid var(--line);border-radius:var(--radius);padding:1rem 1.1rem;
  text-decoration:none;color:var(--ink);display:block;background:#fff}
.rel-card:hover{border-color:var(--blue);box-shadow:var(--shadow)}
.rel-card strong{display:block;color:var(--navy);margin-bottom:.25rem}
.rel-card span{font-size:.93rem;color:var(--muted)}

/* ---------- faq ---------- */
.faq h3{margin-bottom:.2rem}
.faq p{margin-top:.2rem}

/* ---------- footer ---------- */
.site-footer{background:var(--navy);color:#cbd5e1;margin-top:2rem;font-size:.95rem}
.site-footer a{color:#e2e8f0}
.footer-grid{display:grid;grid-template-columns:1fr;gap:1.4rem;padding:2.2rem 0 1.2rem}
@media(min-width:720px){.footer-grid{grid-template-columns:1.4fr 1fr 1fr}}
.footer-brand{display:flex;align-items:center;gap:.5rem;color:#fff;font-weight:800;font-size:1.1rem;
  text-decoration:none;margin-bottom:.5rem}
.footer-brand em{font-style:normal;color:#93c5fd}
.site-footer h4{color:#fff;font-size:1rem;margin:0 0 .5rem}
.site-footer ul{list-style:none;margin:0;padding:0}
.site-footer li{margin:.3rem 0}
.footer-note{border-top:1px solid rgba(255,255,255,.15);padding:1rem 0 1.6rem;font-size:.85rem;color:#94a3b8}
.footer-note p{margin:.3rem 0}

/* ---------- misc pages ---------- */
.narrow{max-width:760px}
.contact-form .field{margin-bottom:1rem}
.contact-form textarea{width:100%;font:inherit;padding:.65rem .8rem;border:1.5px solid #cbd5e1;
  border-radius:8px;min-height:140px}
.error-404{text-align:center;padding:3rem 0}
.error-404 h1{font-size:3rem}
.skip-link{position:absolute;left:-9999px;top:0;background:var(--blue);color:#fff;padding:.6rem 1rem;z-index:99}
.skip-link:focus{left:0}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}}