:root{
  --cream: #EDE4D3;
  --sawdust: #D9C9AE;
  --walnut: #3A2A1D;
  --charcoal: #2B2724;
  --orange: #E8622C;
  --orange-dark: #C44E1F;
  --blue: #3D5A73;
  --blue-light: #6B8AA3;
  --white: #FAF7F0;
}
*{box-sizing:border-box;}
html{scroll-behavior:smooth;}
body{
  margin:0;
  background:var(--cream);
  color:var(--charcoal);
  font-family:'Source Sans 3', sans-serif;
  line-height:1.6;
}
h1,h2,h3,.display{
  font-family:'Oswald', sans-serif;
  color:var(--walnut);
  text-transform:uppercase;
  letter-spacing:0.02em;
  margin:0;
}
.mono{ font-family:'IBM Plex Mono', monospace; }
a{color:var(--blue);}
p{max-width:680px;}

/* ===== Header ===== */
header{
  background:var(--walnut);
  padding:18px 24px;
  display:flex;
  align-items:center;
  justify-content:space-between;
}
.logo{
  color:var(--white);
  font-family:'Oswald', sans-serif;
  font-size:20px;
  font-weight:600;
  text-transform:uppercase;
  letter-spacing:0.03em;
  display:flex;
  align-items:baseline;
  gap:6px;
  text-decoration:none;
}
.logo span{color:var(--orange);}
nav{display:flex; gap:24px;}
nav a{
  color:var(--sawdust);
  text-decoration:none;
  font-size:14px;
  font-weight:600;
  text-transform:uppercase;
  letter-spacing:0.05em;
}
nav a:hover{color:var(--white);}

/* ===== Breadcrumb ===== */
.breadcrumb{
  max-width:1100px;
  margin:0 auto;
  padding:16px 24px 0;
  font-family:'IBM Plex Mono', monospace;
  font-size:12.5px;
  color:var(--blue);
}
.breadcrumb a{color:var(--blue); text-decoration:none;}
.breadcrumb a:hover{text-decoration:underline;}

/* ===== Hero ===== */
.hero{
  max-width:1100px;
  margin:0 auto;
  padding:40px 24px 40px;
  display:grid;
  grid-template-columns:1.1fr 0.9fr;
  gap:40px;
  align-items:center;
}
.hero h1{
  font-size:clamp(30px,4.4vw,46px);
  line-height:1.08;
  font-weight:700;
}
.hero h1 .accent{color:var(--orange);}
.hero p{
  font-size:18px;
  color:var(--charcoal);
  margin-top:16px;
}
.eyebrow{
  display:inline-block;
  font-family:'IBM Plex Mono', monospace;
  font-size:12px;
  font-weight:600;
  letter-spacing:0.12em;
  text-transform:uppercase;
  color:var(--orange-dark);
  background:rgba(232,98,44,0.12);
  padding:5px 10px;
  border-radius:3px;
  margin-bottom:14px;
}

/* ===== Quick-answer callout (for size pages) ===== */
.quick-answer{
  max-width:1100px;
  margin:0 auto;
  padding:0 24px 8px;
}
.quick-answer-box{
  background:var(--white);
  border-left:4px solid var(--orange);
  border-radius:4px;
  padding:18px 22px;
  font-size:17px;
  max-width:760px;
}
.quick-answer-box .actual-big{
  font-family:'IBM Plex Mono', monospace;
  font-weight:600;
  color:var(--orange-dark);
  font-size:19px;
}

/* ===== Ruler / diagram ===== */
.ruler-wrap{
  background:var(--white);
  border:1px solid var(--sawdust);
  border-radius:6px;
  padding:20px;
}
.ruler-caption{
  text-align:center;
  font-family:'IBM Plex Mono', monospace;
  font-size:12px;
  color:var(--blue);
  margin-top:8px;
  letter-spacing:0.04em;
}

/* ===== Section shell ===== */
section{
  max-width:1100px;
  margin:0 auto;
  padding:40px 24px;
}
.section-head{
  display:flex;
  align-items:baseline;
  justify-content:space-between;
  border-bottom:2px solid var(--walnut);
  padding-bottom:12px;
  margin-bottom:28px;
  flex-wrap:wrap;
  gap:10px;
}
.section-head h2{font-size:24px;}
.section-note{
  font-family:'IBM Plex Mono', monospace;
  font-size:12.5px;
  color:var(--blue);
}

/* ===== Size grid ===== */
.size-grid{
  display:grid;
  grid-template-columns:repeat(auto-fill, minmax(120px,1fr));
  gap:10px;
}
.size-btn{
  background:var(--white);
  border:1.5px solid var(--sawdust);
  border-radius:5px;
  padding:14px 8px;
  text-align:center;
  cursor:pointer;
  font-family:'Oswald', sans-serif;
  font-size:18px;
  font-weight:600;
  color:var(--walnut);
  transition:border-color .15s, background .15s;
  text-decoration:none;
  display:block;
}
.size-btn:hover{border-color:var(--blue-light);}
.size-btn.active{
  background:var(--orange);
  border-color:var(--orange-dark);
  color:var(--white);
}

/* ===== Result panel ===== */
.result{
  margin-top:28px;
  background:var(--white);
  border:1px solid var(--sawdust);
  border-radius:6px;
  padding:28px;
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:28px;
  align-items:center;
}
.result-fact{ font-size:15px; }
.result-fact .nominal-label{
  font-family:'IBM Plex Mono', monospace;
  font-size:13px;
  color:var(--charcoal);
  opacity:0.65;
  text-transform:uppercase;
  letter-spacing:0.05em;
}
.result-fact .nominal-val{
  font-family:'Oswald', sans-serif;
  font-size:30px;
  color:var(--walnut);
  font-weight:600;
  margin:2px 0 18px;
}
.result-fact .actual-label{
  font-family:'IBM Plex Mono', monospace;
  font-size:13px;
  color:var(--orange-dark);
  text-transform:uppercase;
  letter-spacing:0.05em;
}
.result-fact .actual-val{
  font-family:'IBM Plex Mono', monospace;
  font-size:34px;
  color:var(--orange-dark);
  font-weight:600;
  margin:4px 0 0;
}
.result-diagram svg{width:100%; height:auto; display:block;}

/* ===== Calculator cards ===== */
.calc-grid{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:24px;
}
.calc-card{
  background:var(--white);
  border:1px solid var(--sawdust);
  border-radius:6px;
  padding:24px;
}
.calc-card h3{ font-size:18px; margin-bottom:4px; }
.calc-card .calc-sub{
  font-size:13px;
  color:var(--charcoal);
  opacity:0.7;
  margin-bottom:18px;
  max-width:none;
}
.field-row{
  display:flex;
  gap:12px;
  margin-bottom:14px;
  flex-wrap:wrap;
}
.field{ flex:1; min-width:120px; }
.field label{
  display:block;
  font-family:'IBM Plex Mono', monospace;
  font-size:11.5px;
  text-transform:uppercase;
  letter-spacing:0.05em;
  color:var(--charcoal);
  opacity:0.7;
  margin-bottom:5px;
}
.field select, .field input{
  width:100%;
  padding:9px 10px;
  border:1.5px solid var(--sawdust);
  border-radius:4px;
  font-family:'IBM Plex Mono', monospace;
  font-size:14px;
  background:var(--cream);
  color:var(--charcoal);
}
.field select:focus, .field input:focus{
  outline:2px solid var(--blue-light);
  outline-offset:1px;
}
.calc-output{
  margin-top:14px;
  padding:14px 16px;
  background:var(--cream);
  border-left:3px solid var(--orange);
  border-radius:4px;
  font-family:'IBM Plex Mono', monospace;
  font-size:14px;
}
.calc-output .big{
  font-size:22px;
  font-weight:600;
  color:var(--walnut);
  display:block;
  margin-bottom:3px;
}

/* ===== Why section (explainer text) ===== */
.why-grid{
  display:grid;
  grid-template-columns:repeat(3, 1fr);
  gap:20px;
}
.why-card{
  background:var(--white);
  border:1px solid var(--sawdust);
  border-radius:6px;
  padding:20px;
}
.why-card .why-num{
  font-family:'IBM Plex Mono', monospace;
  color:var(--orange-dark);
  font-size:13px;
  font-weight:600;
  letter-spacing:0.05em;
}
.why-card h3{ font-size:16px; margin:8px 0 8px; }
.why-card p{ font-size:14px; margin:0; max-width:none; }

/* ===== Reference table ===== */
table{
  width:100%;
  border-collapse:collapse;
  background:var(--white);
  border:1px solid var(--sawdust);
  border-radius:6px;
  overflow:hidden;
}
thead th{
  background:var(--walnut);
  color:var(--white);
  font-family:'Oswald', sans-serif;
  text-transform:uppercase;
  font-size:13px;
  letter-spacing:0.05em;
  padding:12px 16px;
  text-align:left;
}
tbody td{
  padding:11px 16px;
  border-bottom:1px solid var(--sawdust);
  font-size:14.5px;
}
tbody tr:last-child td{border-bottom:none;}
tbody tr.current-row{ background: rgba(232,98,44,0.08); }
td.nom{font-family:'Oswald', sans-serif; font-weight:600; color:var(--walnut);}
td.act{font-family:'IBM Plex Mono', monospace; color:var(--orange-dark); font-weight:600;}

/* ===== Related links ===== */
.related-grid{
  display:grid;
  grid-template-columns:repeat(auto-fill, minmax(160px,1fr));
  gap:10px;
}
.related-link{
  background:var(--white);
  border:1px solid var(--sawdust);
  border-radius:5px;
  padding:12px 14px;
  text-decoration:none;
  display:block;
  transition:border-color .15s;
}
.related-link:hover{ border-color:var(--blue-light); }
.related-link .rl-nom{
  font-family:'Oswald', sans-serif;
  font-weight:600;
  color:var(--walnut);
  font-size:15px;
}
.related-link .rl-act{
  font-family:'IBM Plex Mono', monospace;
  font-size:12.5px;
  color:var(--orange-dark);
  display:block;
  margin-top:2px;
}

footer{
  text-align:center;
  padding:32px 24px 48px;
  font-size:13px;
  color:var(--charcoal);
  opacity:0.6;
}

@media (max-width:760px){
  .hero{grid-template-columns:1fr;}
  .result{grid-template-columns:1fr;}
  .calc-grid{grid-template-columns:1fr;}
  .why-grid{grid-template-columns:1fr;}
  nav{display:none;}
}