:root{color-scheme:dark;--bg:#121a2c;--card:#1c2740;--ink:#f5f6ff;--muted:#c0cce4;--line:#425171;--mint:#7fe8cb;--coral:#ffb49f;--dark:#10241f;font-family:system-ui,sans-serif;color:var(--ink);background:var(--bg)}
*{box-sizing:border-box}
body{margin:0}
.shell{width:min(1080px,calc(100% - 34px));margin-inline:auto}
.top,.head{display:flex;justify-content:space-between;align-items:center;gap:10px}
.top{height:67px;border-bottom:1px solid var(--line)}
a{color:var(--mint)}
.brand{display:inline-flex;align-items:center;gap:8px;text-decoration:none;color:var(--ink);font-weight:820}
.brand span{background:var(--mint);color:var(--dark);padding:4px 11px;border-radius:8px;font:italic 800 1.2rem Georgia,serif}
.intro{padding:48px 0 29px}
.eyebrow{color:var(--mint);font-size:.75rem;font-weight:820;letter-spacing:.12em;text-transform:uppercase;margin:0 0 8px}
h1,h2,p{margin-top:0}
h1{font-size:clamp(2.9rem,8.8vw,6.7rem);line-height:.89;letter-spacing:-.086em;margin-bottom:20px}
h2{font-size:clamp(1.45rem,4vw,2.17rem);letter-spacing:-.043em;margin-bottom:9px}
p{line-height:1.53}
.intro p:last-child,.guide p:not(.eyebrow){color:var(--muted);max-width:64ch}
.card{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:clamp(15px,3.4vw,29px);margin-bottom:15px}
.head{align-items:flex-start}
.fields{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:9px}
.fields.observed{grid-template-columns:repeat(2,minmax(0,1fr))}
label{font-size:.88rem;font-weight:730}
input,select,button{font:inherit}
input,select{display:block;width:100%;color:var(--ink);background:#172236;border:1px solid var(--line);border-radius:8px;margin:5px 0 10px;padding:8px}
button{background:#263753;border:1px solid var(--line);border-radius:8px;color:var(--ink);font-weight:750;font-size:.85rem;padding:8px 10px;cursor:pointer}
button.primary{background:var(--mint);color:var(--dark);border-color:var(--mint)}
:focus-visible{outline:3px solid var(--mint);outline-offset:3px}
#notice,#precision,#observedResult{color:var(--muted);font-size:.89rem;margin:9px 0}
#required{color:var(--mint);font-weight:750;margin-bottom:0}
.table-wrap{overflow:auto;border:1px solid var(--line);border-radius:8px}
table{width:100%;min-width:435px;border-collapse:collapse;text-align:left;font-variant-numeric:tabular-nums}
th,td{border-bottom:1px solid var(--line);padding:8px 10px}
th{font-size:.83rem;background:#172236}
#intervalChart svg{width:100%;display:block;height:auto;margin-top:7px}
.chart-axis{stroke:#657697;stroke-width:1.5}
.chart-a{stroke:var(--mint);fill:var(--mint)}
.chart-b{stroke:var(--coral);fill:var(--coral)}
.chart-label{fill:var(--muted);font:14px system-ui,sans-serif}
footer{border-top:1px solid var(--line);padding:15px 0 24px;color:var(--muted);font-size:.85rem}
@media(max-width:680px){.fields{grid-template-columns:repeat(2,minmax(0,1fr))}.head{flex-wrap:wrap}.intro{padding-top:34px}}
@media(max-width:390px){.fields,.fields.observed{grid-template-columns:1fr}}