:root{
  --paper:#f6f4ee; --panel:#ffffff; --ink:#151b23; --muted:#5a6470;
  --line:#e2ddca; --line-soft:#ece8d9;
  --accent:#e2621f; --accent-dark:#b74d16; --accent-soft:#fbe4d1;
  --blue:#20415a; --blue-soft:#e6edf1;
  --warn:#8a5813; --warn-soft:#fbf0da;
  --danger:#a3372b; --danger-soft:#fbe9e6;
  --ink-inverse:#f6f4ee;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;background:var(--paper);color:var(--ink);
  font-family:"Inter",sans-serif;line-height:1.55;-webkit-font-smoothing:antialiased;
}
h1,h2,h3{font-family:"Fraunces",serif;font-weight:700;letter-spacing:-0.015em;margin:0}
p{margin:0}
button,input,select,textarea{font:inherit;color:inherit}
button{cursor:pointer}
a{color:inherit;text-decoration:none}
img{max-width:100%;display:block}
button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
.wrap{width:min(1100px,calc(100% - 48px));margin:0 auto}

/* ---------- header ---------- */
.site-header{position:sticky;top:0;z-index:40;background:rgba(246,244,238,.94);backdrop-filter:blur(10px);border-bottom:1px solid var(--line)}
.header-row{display:flex;align-items:center;gap:30px;min-height:72px}
.brand{display:flex;align-items:center;gap:10px;font-family:"Fraunces",serif;font-weight:700;font-size:1.35rem;color:var(--ink)}
.brand-mark{width:28px;height:28px;flex:none}
.desktop-nav{display:flex;align-items:center;gap:28px;margin-left:auto}
.nav-link{border:0;background:none;padding:8px 0;font-size:.92rem;font-weight:600;color:var(--muted);position:relative}
.nav-link:hover{color:var(--ink)}
.nav-link[aria-current="page"]{color:var(--ink)}
.nav-link[aria-current="page"]::after{content:"";position:absolute;left:0;right:0;bottom:0;height:2px;background:var(--accent)}
.header-cta{margin-left:8px}
.menu-toggle{display:none;margin-left:auto;border:0;background:transparent;color:var(--ink);padding:8px}
.mobile-nav{display:none;padding:6px 0 16px;border-top:1px solid var(--line)}
.mobile-nav.open{display:grid;gap:2px}
.mobile-nav .nav-link{text-align:left;padding:10px 2px}

/* ---------- buttons ---------- */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;border:1.5px solid transparent;border-radius:3px;padding:12px 20px;font-size:.92rem;font-weight:700;transition:background .15s,border-color .15s,color .15s,transform .12s}
.btn-primary{background:var(--accent);color:#fff}
.btn-primary:hover{background:var(--accent-dark);transform:translateY(-1px)}
.btn-outline{background:transparent;border-color:var(--ink);color:var(--ink)}
.btn-outline:hover{background:var(--ink);color:var(--ink-inverse)}
.btn-small{padding:10px 15px;font-size:.85rem}

/* ---------- hero ---------- */
.hero{padding:76px 0 60px;border-bottom:1px solid var(--line)}
.hero-grid{display:grid;grid-template-columns:1.12fr .88fr;gap:56px;align-items:center}
.hero h1{font-size:3.15rem;line-height:1.04;margin-bottom:18px}
.hero .lede{color:var(--muted);font-size:1.08rem;line-height:1.68;max-width:46ch}
.hero-actions{display:flex;flex-wrap:wrap;gap:12px;margin-top:28px}
.hero-figure{border:1px solid var(--line);background:var(--panel);border-radius:6px;padding:20px;box-shadow:0 1px 0 var(--line)}
.hero-figure svg{width:100%;height:auto;display:block}
.hero-figure figcaption{margin-top:12px;font-size:.82rem;color:var(--muted)}

.ruler{display:flex;margin-top:38px;border-top:1px solid var(--line-soft)}
.ruler div{flex:1;padding:16px 4px 0;border-right:1px solid var(--line-soft)}
.ruler div:last-child{border-right:0}
.ruler strong{display:block;font-family:"Fraunces",serif;font-weight:700;font-size:1.65rem;color:var(--accent)}
.ruler span{display:block;color:var(--muted);font-size:.83rem;margin-top:3px}

/* ---------- sections ---------- */
.section{padding:64px 0}
.section-tint{background:var(--blue-soft)}
.section-head{max-width:640px;margin-bottom:32px}
.section-head h2{font-size:2rem;margin-bottom:12px}
.section-head p{color:var(--muted);line-height:1.65}

.feature-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:1px;background:var(--line);border:1px solid var(--line);border-radius:6px;overflow:hidden}
.feature-card{background:var(--panel);padding:26px}
.feature-card .num{font-family:"Fraunces",serif;font-weight:700;color:var(--accent);font-size:1rem}
.feature-card h3{margin:12px 0 8px;font-size:1.1rem}
.feature-card p{color:var(--muted);font-size:.9rem;line-height:1.6}

/* ---------- page hero (sub pages) ---------- */
.page-hero{padding:50px 0 32px;border-bottom:1px solid var(--line)}
.page-hero h1{font-size:2.35rem;margin:4px 0 12px}
.page-hero p{color:var(--muted);max-width:60ch;line-height:1.6}

/* ---------- calculator ---------- */
.calc-section{padding:50px 0 74px}
.calc-layout{display:grid;grid-template-columns:minmax(300px,.82fr) minmax(400px,1.18fr);gap:24px;align-items:start}
.panel{border:1px solid var(--line);border-radius:6px;background:var(--panel)}
.calc-inputs{padding:24px}
.panel-title{font-size:1.15rem;margin-bottom:18px}
.input-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:14px}
.field-wide{grid-column:1/-1}
.field label{display:block;margin-bottom:6px;color:var(--muted);font-size:.78rem;font-weight:600}
.field input,.field select{width:100%;min-height:44px;padding:9px 12px;border:1.5px solid #d0c9b3;border-radius:4px;background:#fff}
.field input:focus,.field select:focus{border-color:var(--accent)}
.helptext{margin:18px 0 0;padding:12px 13px;border:1px solid #e6cda3;border-radius:4px;background:var(--accent-soft);color:var(--accent-dark);font-size:.83rem;line-height:1.55}
.error-text{margin-top:14px;padding:12px 13px;border:1px solid #e5b6ae;border-radius:4px;background:var(--danger-soft);color:var(--danger);font-size:.85rem}
.warn-text{margin-top:22px;padding:12px 13px;border:1px solid #e9cf8e;border-radius:4px;background:var(--warn-soft);color:var(--warn);font-size:.83rem;line-height:1.55}
.hidden{display:none!important}

.diagram-card{overflow:hidden}
.diagram-header{padding:15px 20px;border-bottom:1px solid var(--line)}
.diagram-header strong{display:block;font-size:.98rem;font-family:"Fraunces",serif}
.diagram-header span{font-size:.78rem;color:var(--muted)}
.diagram-wrap{padding:15px;background:#fff;overflow:auto}
#stairSvg{display:block;width:100%;min-width:420px;background:#fbfaf5;border-radius:4px}

.results{margin-top:20px}
.primary-results{display:grid;grid-template-columns:repeat(4,1fr);gap:1px;background:var(--line);border:1px solid var(--line);border-radius:6px;overflow:hidden}
.result-card{background:var(--panel);padding:15px;border-top:3px solid var(--accent)}
.result-card span{display:block;color:var(--muted);font-size:.72rem;font-weight:600}
.result-card strong{display:block;margin-top:6px;font-size:1.2rem;font-family:"Fraunces",serif}
.result-card em{display:block;margin-top:4px;font-style:normal;font-size:.7rem;font-weight:700;color:var(--accent)}
.result-card em.flag{color:var(--danger)}
.secondary-results{display:grid;grid-template-columns:repeat(4,1fr);background:var(--panel);border:1px solid var(--line);border-top:0;border-radius:0 0 6px 6px;overflow:hidden}
.secondary-results div{padding:13px 15px;border-right:1px solid var(--line)}
.secondary-results div:last-child{border-right:0}
.secondary-results small{display:block;color:var(--muted);font-size:.72rem}
.secondary-results strong{display:block;margin-top:4px;font-size:.94rem;font-family:"Fraunces",serif}

.action-row{display:flex;flex-wrap:wrap;gap:10px;margin-top:20px}
.status-message{min-height:20px;margin-top:10px;color:var(--blue);font-size:.83rem}

/* ---------- guides ---------- */
.guide-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:18px}
.guide-card{border:1px solid var(--line);border-radius:6px;background:var(--panel);padding:24px;display:flex;gap:18px}
.guide-mark{flex:0 0 auto;font-family:"Fraunces",serif;font-weight:700;color:var(--accent);font-size:1.15rem;line-height:1;padding-top:2px}
.guide-card h3{font-size:1.05rem;margin-bottom:7px}
.guide-card p{color:var(--muted);font-size:.9rem;line-height:1.65}

/* ---------- about ---------- */
.about-layout{display:grid;grid-template-columns:.85fr 1.15fr;gap:38px;align-items:start}
.about-figure{border:1px solid var(--line);background:var(--panel);border-radius:6px;padding:20px}
.about-figure svg{width:100%;height:auto}
.about-copy h2{font-size:1.6rem;margin-bottom:14px}
.about-copy p{color:var(--muted);line-height:1.7;margin-bottom:15px}

/* ---------- faq ---------- */
.faq-list{display:grid;gap:10px;max-width:820px}
.faq-item{border:1px solid var(--line);border-radius:6px;background:var(--panel);overflow:hidden}
.faq-question{width:100%;display:flex;align-items:center;justify-content:space-between;gap:16px;border:0;background:transparent;padding:18px 20px;text-align:left;font-weight:700;font-size:.96rem}
.faq-question svg{flex:none;transition:transform .15s}
.faq-item.open .faq-question svg{transform:rotate(180deg)}
.faq-answer{display:none;padding:0 20px 20px;color:var(--muted);line-height:1.7;font-size:.9rem}
.faq-item.open .faq-answer{display:block}

/* ---------- contact ---------- */
.contact-layout{display:grid;grid-template-columns:.9fr 1.1fr;gap:32px;align-items:start}
.contact-panel{border:1px solid var(--line);border-radius:6px;background:var(--panel);padding:26px}
.contact-copy h2{font-size:1.5rem;margin-bottom:14px}
.contact-copy p{color:var(--muted);line-height:1.7;margin-bottom:15px}

/* ---------- legal ---------- */
.legal-layout{max-width:780px}
.legal-layout h2{font-size:1.2rem;margin:28px 0 8px}
.legal-layout h2:first-child{margin-top:0}
.legal-layout p{color:var(--muted);line-height:1.75}

.nf-code{font-family:"Fraunces",serif;font-weight:700;font-size:.9rem;color:var(--accent)}

/* ---------- footer ---------- */
.site-footer{padding:38px 0 26px;background:var(--ink);color:#d9d4c6}
.footer-row{display:flex;justify-content:space-between;align-items:flex-start;gap:30px;flex-wrap:wrap}
.footer-brand{font-family:"Fraunces",serif;font-weight:700;font-size:1.1rem;color:#fff}
.footer-copy{max-width:520px;margin-top:10px;color:#aba692;font-size:.82rem;line-height:1.65}
.footer-links{display:flex;flex-wrap:wrap;gap:15px}
.footer-link{border:0;background:none;padding:0;color:#d9d4c6;font-size:.83rem;font-weight:500}
.footer-link:hover{color:#fff}
.footer-bottom{margin-top:26px;padding-top:18px;border-top:1px solid #3a4048;color:#847f6d;font-size:.76rem}

@media(max-width:860px){
  .desktop-nav,.header-cta{display:none}
  .menu-toggle{display:inline-flex}
  .hero-grid,.calc-layout,.about-layout,.contact-layout{grid-template-columns:1fr;gap:26px}
  .feature-grid{grid-template-columns:1fr}
  .guide-grid{grid-template-columns:1fr}
  .primary-results{grid-template-columns:repeat(2,1fr)}
  .secondary-results{grid-template-columns:repeat(2,1fr)}
  .secondary-results div:nth-child(-n+2){border-bottom:1px solid var(--line)}
  .ruler{flex-wrap:wrap}
  .ruler div{flex:0 0 50%;margin-bottom:12px}
}
@media(max-width:560px){
  .hero h1{font-size:2.2rem}
  .input-grid{grid-template-columns:1fr}
  .field-wide{grid-column:auto}
  .action-row .btn{flex:1 1 130px}
  .primary-results,.secondary-results{grid-template-columns:1fr 1fr}
}

@media print{
  .site-header,.site-footer,.no-print{display:none!important}
  body{background:#fff}
  .calc-section{padding:0}
  .calc-layout{grid-template-columns:1fr}
  .panel{border:0}
  .calc-inputs{padding:0 0 16px}
}