:root{
  --bg:#eef3f7;
  --surface:#ffffff;
  --surface-2:#f7fafc;
  --ink:#17212b;
  --muted:#5e6d7c;
  --accent:#1769d6;
  --accent-2:#0f8b6f;
  --accent-ink:#ffffff;
  --gold:#f2b84b;
  --border:#d8e1ea;
  --border-strong:#b9c8d6;
  --warn:#b46910;
  --shadow:0 18px 45px rgba(23,33,43,.10);
  --shadow-soft:0 8px 22px rgba(23,33,43,.07);
}
*{box-sizing:border-box}
html{min-height:100%}
body{
  margin:0;
  min-height:100%;
  background:
    linear-gradient(180deg,#ddeaf4 0,#eef3f7 260px,#f7f9fb 100%);
  color:var(--ink);
  font:16px/1.5 system-ui,-apple-system,Segoe UI,Roboto,Helvetica,Arial,sans-serif;
}
a{color:var(--accent);text-decoration-thickness:1px;text-underline-offset:3px}
a:hover{color:#0d4f9e}
.wrap{max-width:1080px;margin:0 auto;padding:28px 18px 52px}

.topbar{
  position:sticky;
  top:0;
  z-index:10;
  background:rgba(255,255,255,.88);
  border-bottom:1px solid rgba(216,225,234,.85);
  backdrop-filter:blur(14px);
}
.topbar-inner{max-width:1080px;margin:0 auto;padding:12px 18px;display:flex;align-items:center;gap:20px;flex-wrap:wrap}
.brand{display:inline-flex;align-items:center;gap:10px;font-weight:850;color:var(--ink);text-decoration:none;font-size:1.12rem;letter-spacing:0}
.brand:before{content:"";width:30px;height:30px;border-radius:8px;background:linear-gradient(135deg,var(--accent),var(--accent-2));box-shadow:inset 0 0 0 1px rgba(255,255,255,.45)}
.topnav{display:flex;gap:6px;flex-wrap:wrap}
.topnav a{
  color:#334353;
  text-decoration:none;
  font-size:.88rem;
  font-weight:650;
  padding:7px 9px;
  border-radius:8px;
}
.topnav a:hover{background:#edf4fb;color:var(--accent)}

.hero{
  position:relative;
  padding:34px 0 26px;
  border-bottom:1px solid rgba(216,225,234,.7);
  margin-bottom:24px;
}
.hero:before{
  content:"";
  display:block;
  width:68px;
  height:5px;
  margin-bottom:14px;
  border-radius:999px;
  background:linear-gradient(90deg,var(--accent),var(--accent-2),var(--gold));
}
.hero h1{font-size:clamp(2rem,4vw,3.35rem);line-height:1.02;margin:0 0 10px;font-weight:900;max-width:760px;letter-spacing:0}
.hero p{color:var(--muted);margin:0;max-width:760px;font-size:1.03rem}

.grid{display:grid;gap:20px;grid-template-columns:1fr}
@media(min-width:860px){.grid{grid-template-columns:minmax(320px,380px) 1fr;align-items:start}}
.card{
  background:rgba(255,255,255,.94);
  border:1px solid var(--border);
  border-radius:8px;
  padding:20px;
  box-shadow:var(--shadow-soft);
}
.grid .card:first-child{position:sticky;top:78px}
.card h2{font-size:1.02rem;margin:0 0 14px;font-weight:800}

textarea{
  width:100%;
  min-height:188px;
  resize:vertical;
  font:14px/1.55 ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  padding:12px;
  border:1px solid var(--border-strong);
  border-radius:8px;
  background:#fbfdff;
  color:var(--ink);
  box-shadow:inset 0 1px 2px rgba(23,33,43,.04);
}
textarea:focus,.field input:focus,.field select:focus,input[type=text]:focus{
  outline:3px solid rgba(242,184,75,.42);
  border-color:var(--gold);
  background:#fff;
}
.field{display:block;margin-bottom:12px;font-size:.86rem;color:var(--muted);font-weight:700}
.field input,.field select{
  display:block;
  width:100%;
  margin-top:5px;
  padding:10px 11px;
  border:1px solid var(--border-strong);
  border-radius:8px;
  background:#fbfdff;
  font-size:1rem;
  color:var(--ink);
}
.row{display:flex;gap:8px;flex-wrap:wrap;align-items:center}
input[type=text]{
  flex:1 1 auto;
  min-width:140px;
  padding:10px 11px;
  border:1px solid var(--border-strong);
  border-radius:8px;
  background:#fbfdff;
  font-size:14px;
}
button{
  cursor:pointer;
  border:1px solid transparent;
  border-radius:8px;
  padding:10px 14px;
  font-size:14px;
  font-weight:800;
  background:linear-gradient(135deg,var(--accent),#1257b2);
  color:var(--accent-ink);
  box-shadow:0 8px 16px rgba(23,105,214,.18);
}
button.secondary{background:#f4f7fb;color:#263544;border-color:var(--border);box-shadow:none}
button.link{background:none;color:var(--accent);padding:4px 7px;font-weight:750;border:0;box-shadow:none}
button:hover{transform:translateY(-1px);filter:saturate(1.06)}
button:active{transform:translateY(0)}

.headline{
  display:inline-block;
  font-size:clamp(1.9rem,4vw,2.65rem);
  line-height:1.05;
  font-weight:900;
  color:var(--accent);
  margin:2px 0 8px;
}
.headline small{display:block;margin-top:5px;font-size:.86rem;color:var(--muted);font-weight:700}
.stats{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px;margin-top:14px}
.stat{
  min-width:0;
  background:linear-gradient(180deg,#ffffff,#f6f9fc);
  border:1px solid var(--border);
  border-radius:8px;
  padding:11px;
}
.stat .k{font-size:.76rem;color:var(--muted);font-weight:750;text-transform:uppercase;letter-spacing:.02em}
.stat .v{font-size:1.08rem;font-weight:850;overflow-wrap:anywhere}
.subhead{font-size:.95rem;margin:20px 0 8px;font-weight:850}
svg{display:block;margin-top:8px;background:#fbfdff;border:1px solid var(--border);border-radius:8px;padding:8px}

table{width:100%;border-collapse:collapse;font-size:14px;margin-top:8px;background:#fff;border:1px solid var(--border);border-radius:8px;overflow:hidden}
th,td{text-align:right;padding:8px 10px;border-bottom:1px solid var(--border)}
tr:last-child td{border-bottom:0}
th:first-child,td:first-child{text-align:left}
th{background:#f3f7fb;color:#425263;font-size:.78rem;text-transform:uppercase;letter-spacing:.02em}
.muted{color:var(--muted)}
.saved-item{display:flex;align-items:center;justify-content:space-between;gap:8px;padding:9px 0;border-bottom:1px solid var(--border)}
.saved-item .name{font-weight:800}
details{margin-top:14px}
summary{cursor:pointer;font-weight:800}
.formula{font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;background:#f3f7fb;padding:9px 11px;border-radius:8px;display:inline-block;margin:8px 0;border:1px solid var(--border)}

.site-foot{border-top:1px solid var(--border);background:rgba(255,255,255,.86);margin-top:24px}
.site-foot .wrap{padding:18px}
.cardlist{list-style:none;padding:0;margin:0;display:grid;grid-template-columns:repeat(auto-fit,minmax(210px,1fr));gap:10px}
.cardlist li{min-width:0}
.cardlist a{
  display:flex;
  align-items:center;
  min-height:44px;
  padding:10px 12px;
  border:1px solid var(--border);
  border-radius:8px;
  background:linear-gradient(180deg,#fff,#f7fafc);
  color:#223242;
  font-weight:800;
  text-decoration:none;
}
.cardlist a:before{content:"";width:7px;height:22px;border-radius:999px;background:var(--accent-2);margin-right:10px;flex:0 0 auto}
.cardlist a:hover{border-color:#9db9d6;box-shadow:var(--shadow-soft);transform:translateY(-1px);color:var(--accent)}
.cardlist .desc{color:var(--muted);font-size:.9rem}
.content-guide{
  margin-top:26px;
  padding-top:26px;
  border-top:1px solid rgba(216,225,234,.85);
}
.guide-grid{display:grid;gap:18px;grid-template-columns:1fr}
@media(min-width:860px){.guide-grid{grid-template-columns:minmax(0,1fr) 310px;align-items:start}}
.guide-main,.guide-side{
  background:rgba(255,255,255,.94);
  border:1px solid var(--border);
  border-radius:8px;
  padding:20px;
  box-shadow:var(--shadow-soft);
}
.guide-main .eyebrow{
  margin:0 0 8px;
  color:var(--accent-2);
  font-size:.76rem;
  font-weight:850;
  letter-spacing:.08em;
  text-transform:uppercase;
}
.guide-main h2{font-size:1.55rem;line-height:1.18;margin:0 0 10px;font-weight:900}
.guide-main h3,.guide-side h3{font-size:1rem;margin:18px 0 8px;font-weight:850}
.guide-main p,.guide-side p{color:#334353;margin:0 0 12px}
.guide-main ol{margin:0;padding-left:22px;color:#334353}
.guide-main li{margin:7px 0}
.formula-block{
  margin:16px 0;
  padding:13px 14px;
  border:1px solid #c8d9e8;
  border-left:5px solid var(--accent);
  border-radius:8px;
  background:#f6fafd;
  font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  color:#17212b;
  overflow-wrap:anywhere;
}
.guide-side details{
  margin:0 0 9px;
  padding:10px 11px;
  border:1px solid var(--border);
  border-radius:8px;
  background:#fbfdff;
}
.guide-side summary{font-size:.92rem}
.guide-side details p{margin:8px 0 0;font-size:.92rem;color:var(--muted)}
.related-links{list-style:none;margin:0;padding:0;display:grid;gap:8px}
.related-links a{
  display:block;
  padding:9px 10px;
  border:1px solid var(--border);
  border-radius:8px;
  background:#f7fafc;
  color:#263544;
  font-weight:750;
  text-decoration:none;
}
.related-links a:hover{border-color:#9db9d6;color:var(--accent)}

@media(max-width:620px){
  .wrap{padding:20px 12px 40px}
  .topbar-inner{padding:10px 12px;gap:10px}
  .topnav{overflow:auto;flex-wrap:nowrap;width:100%;padding-bottom:2px}
  .topnav a{white-space:nowrap}
  .hero{padding:24px 0 20px}
  .card{padding:16px}
  .grid .card:first-child{position:static}
  .stats{grid-template-columns:1fr}
  button{flex:1 1 auto}
}
@media print{
  .topbar,.site-foot,.no-print,textarea{display:none!important}
  body{background:#fff}
  .wrap{max-width:100%;padding:0}
  .grid{display:block}
  .card{border:none;padding:6px 0;box-shadow:none}
  svg{border:1px solid #ddd}
}