/* SteelInfo: plain, fast, 2019-style stylesheet. No web fonts, no gradients. */
:root{
  color-scheme:light;
  --bg:#eef0f3;--panel:#fff;--text:#222;--muted:#666;--line:#d5d9de;--line2:#e7e9ec;
  --brand:#1d3557;--brand2:#264b7a;--accent:#e76f24;--link:#1a5fb4;--link-h:#0d3f80;
  /* accent-ink: orange for text on light backgrounds; accent-btn: orange behind white text (both ≥ 4.5:1) */
  --accent-ink:#c2410c;--accent-btn:#c2410c;--accent-btn-h:#9a3412;
  --th:#f3f5f7;--stripe:#fafbfc;--hl:#fff4d6;--ok:#2e7d32;--fail:#c62828;--sheet:#fff;--ad:#f7f7f7;
}
:root[data-theme="dark"]{
  color-scheme:dark;
  --bg:#15181c;--panel:#1e2227;--text:#e3e6ea;--muted:#9aa3ad;--line:#353b43;--line2:#2b3037;
  --brand:#14253d;--brand2:#1d3557;--link:#7db3f5;--link-h:#a9cdfa;--th:#252a31;--stripe:#22262c;--hl:#3b3420;--ad:#23272d;
  --accent-ink:#f08a4b;--ok:#66bb6a;--fail:#ef6f6c;
}
*{box-sizing:border-box}
[hidden]{display:none!important}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--text);font:15px/1.55 "Segoe UI",Arial,Helvetica,sans-serif}
a{color:var(--link);text-decoration:none}a:hover{color:var(--link-h);text-decoration:underline}
h1,h2,h3{font-weight:600;line-height:1.25;color:var(--text)}
h1{font-size:26px;margin:4px 0 10px}h2{font-size:19px;margin:28px 0 10px;padding-bottom:6px;border-bottom:1px solid var(--line)}
h3{font-size:16px;margin:20px 0 8px}
small{font-size:12px}
.wrap{max-width:1240px;margin:0 auto;padding:0 16px}
.skip{position:absolute;left:-999px}.skip:focus{left:8px;top:8px;background:#fff;padding:6px;z-index:9}

/* top bar + header */
.topbar{background:#0f1f33;color:#b9c4d2;font-size:12px}
.topbar .wrap{display:flex;justify-content:space-between;align-items:center;min-height:30px;gap:10px}
.topbar a{color:#d6dde6;margin-left:14px}
.theme-btn{background:none;border:1px solid #4a5a6e;color:#d6dde6;font-size:11px;padding:2px 8px;margin-left:14px;border-radius:3px;cursor:pointer}
.theme-btn[aria-pressed="true"]{background:#4a5a6e;color:#fff}
.hdr{background:var(--brand);color:#fff}
.hdr>.wrap{display:flex;align-items:center;gap:20px;padding-top:12px;padding-bottom:12px}
.logo{display:flex;align-items:center;gap:9px;color:#fff;font-size:24px;letter-spacing:-.5px}
.logo:hover{text-decoration:none;color:#fff}.logo svg{width:34px;height:34px}.logo b{color:var(--accent)}
.search{flex:1;max-width:560px;display:flex;position:relative;margin-left:auto}
.search input{flex:1;border:1px solid #0b1626;border-right:0;padding:8px 10px;font-size:14px;border-radius:3px 0 0 3px;min-width:0;background:#fff;color:#222}
.search button{border:0;background:var(--accent-btn);color:#fff;padding:0 16px;font-size:14px;border-radius:0 3px 3px 0;cursor:pointer}
.search button:hover{background:var(--accent-btn-h)}
.sugg{position:absolute;top:100%;left:0;right:0;background:var(--panel);border:1px solid var(--line);z-index:50;max-height:360px;overflow:auto;box-shadow:0 4px 10px rgba(0,0,0,.15)}
.sugg a{display:flex;justify-content:space-between;padding:6px 10px;color:var(--text);border-bottom:1px solid var(--line2)}
.sugg a:hover,.sugg a.on{background:var(--th);text-decoration:none}.sugg small{color:var(--muted)}
.menu-btn{display:none;background:none;border:1px solid #4a6487;color:#fff;padding:6px 10px;border-radius:3px}
.nav{background:var(--brand2);border-top:1px solid #345c8f}
.nav .wrap{display:flex;align-items:center}
.nav-l{list-style:none;margin:0;padding:0;display:flex;flex-wrap:wrap}
.nav-l>li>a{display:block;color:#e8eef6;padding:10px 14px;font-size:14px}
.nav-l>li>a:hover{background:#1d3e66;text-decoration:none;color:#fff}
.caret{display:inline-block;border:4px solid transparent;border-top-color:#e8eef6;margin-left:4px;vertical-align:-2px}
.has-mm{position:relative}
.mm{display:none;position:absolute;left:0;top:100%;background:var(--panel);border:1px solid var(--line);box-shadow:0 6px 16px rgba(0,0,0,.18);z-index:40;padding:14px;gap:22px;width:760px}
.has-mm:hover .mm,.has-mm:focus-within .mm{display:flex}
.mm-col{flex:1}.mm-h{font-size:11px;text-transform:uppercase;letter-spacing:.5px;color:var(--muted);margin-bottom:6px;font-weight:600}
.mm ul{list-style:none;margin:0;padding:0}.mm li a{display:flex;align-items:center;gap:8px;padding:4px 0;color:var(--text);font-size:14px}
.ico{width:16px;height:16px;fill:var(--muted);color:var(--muted);flex:none}.ico-l{width:40px;height:40px;fill:var(--brand2);flex:none}
:root[data-theme="dark"] .ico-l{fill:#7da3d1}
.cmp-pill{margin-left:auto;background:var(--accent-btn);color:#fff;padding:4px 12px;border-radius:3px;font-size:13px}
.cmp-pill:hover{color:#fff}

/* layout */
.lb{padding-top:14px}
.layout{display:grid;grid-template-columns:minmax(0,1fr) 300px;gap:20px;padding-top:14px;padding-bottom:30px}
.layout.wide{grid-template-columns:minmax(0,1fr)}
.content{background:var(--panel);border:1px solid var(--line);padding:18px 24px 26px;border-radius:3px;min-width:0}
.side{min-width:0}.side>*{margin-bottom:16px}
.sticky{position:sticky;top:10px}
.panel{background:var(--panel);border:1px solid var(--line);border-radius:3px}
.panel-h{background:var(--th);border-bottom:1px solid var(--line);padding:8px 12px;font-weight:600;font-size:14px}
.fam-list{list-style:none;margin:0;padding:4px 0}.fam-list a{display:flex;gap:8px;align-items:center;padding:5px 12px;color:var(--text);font-size:14px}
.fam-list a:hover{background:var(--th);text-decoration:none}.fam-list .on a{background:var(--hl);font-weight:600}
.sponsors{list-style:none;margin:0;padding:6px 12px}.sponsors li{padding:6px 0;border-bottom:1px solid var(--line2)}.sponsors span{display:block;font-size:12px;color:var(--muted)}

/* ads (space reserved to avoid layout shift) */
.ad{background:var(--ad);border:1px dashed var(--line);display:flex;flex-direction:column;align-items:stretch;justify-content:center;position:relative;overflow:hidden;margin:0 auto}
.ad-lbl{position:absolute;top:2px;right:6px;font-size:10px;color:var(--muted);text-transform:uppercase;letter-spacing:.5px}
.ad-leader{width:100%;max-width:728px;min-height:90px}
.ad-sidebar{width:300px;min-height:250px}.ad-tall{width:300px;min-height:600px}
.ad-inline{width:100%;min-height:120px;margin:22px 0}
.ad-house{display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center;flex:1;padding:10px;color:var(--muted)}
.ad-house strong{color:var(--text);font-size:15px}.ad-house span{font-size:12px}
.ad-house:hover{text-decoration:none;background:var(--th)}

/* breadcrumbs, titles */
.crumbs{font-size:13px;color:var(--muted);margin-bottom:8px}.crumbs i{font-style:normal;margin:0 4px}
.title-row{display:flex;flex-wrap:wrap;align-items:center;gap:8px}.title-row h1{margin-right:6px}
.sub{font-weight:400;color:var(--muted);font-size:19px}
.badge{display:inline-block;background:var(--th);border:1px solid var(--line);color:var(--text);font-size:12px;padding:2px 8px;border-radius:3px}
.lead{font-size:16px;color:var(--text)}
.note{font-size:13px;color:var(--muted)}
.aka{font-size:13px;color:var(--muted);margin-top:-6px}
.tool-disc{margin-top:14px}

/* buttons */
.btn{display:inline-flex;align-items:center;gap:6px;border:1px solid var(--line);background:var(--panel);color:var(--text);padding:7px 12px;border-radius:3px;font-size:14px;cursor:pointer;font-family:inherit;line-height:1.2}
.btn:hover{background:var(--th);text-decoration:none;color:var(--text)}
.btn-p{background:var(--brand2);border-color:var(--brand2);color:#fff}.btn-p:hover{background:var(--brand);color:#fff}
.btn-c{border-color:var(--accent-ink);color:var(--accent-ink)}.btn-c.added{background:var(--accent-btn);border-color:var(--accent-btn);color:#fff}
.i16{width:14px;height:14px;fill:currentColor}
.dl-row{display:flex;flex-wrap:wrap;gap:8px;margin:12px 0}

/* drawing sheet */
.sheet-wrap{border:1px solid var(--line);background:#fff;margin:10px 0;overflow:auto}
.sheet{display:block;width:100%;height:auto}
.sheet-full{display:none;font-size:13px;margin:-4px 0 8px}
.pn{display:flex;justify-content:space-between;font-size:14px;margin:6px 0}
.fam-intro{display:grid;grid-template-columns:minmax(0,1fr) 300px;gap:20px;align-items:start}
.key{margin:0;border:1px solid var(--line);background:#fff;padding:6px;text-align:center}
.key figcaption{font-size:12px;color:#666}.keysvg{width:100%;height:auto;max-height:300px}

/* tables */
table{border-collapse:collapse;width:100%;font-size:14px}
caption{text-align:left;font-weight:600;padding:0 0 6px;font-size:14px}
th,td{border:1px solid var(--line);padding:5px 8px;vertical-align:top}
th{background:var(--th);font-weight:600;text-align:left}
tbody tr:nth-child(even){background:var(--stripe)}
.num{text-align:right;font-variant-numeric:tabular-nums;white-space:nowrap}
.props .sym{white-space:nowrap;font-family:"Times New Roman",Times,serif;font-style:italic;font-size:15px}
.props .u{white-space:nowrap;color:var(--muted);font-size:13px}
.cap td,.cap th{text-align:right}
.tbl-wrap{overflow:auto;max-width:100%;margin:8px 0}
.list th{white-space:nowrap;line-height:1.2;font-size:13px}
.list td{white-space:nowrap}
.list.wrap td{white-space:normal;min-width:90px}
.guides li{margin-bottom:12px}
.list .dn a{font-weight:600}
/* family tables: each row opens its section page (site.js); the arrow and callout make that obvious */
.list.sortable .dn a:after{content:" \203A";color:var(--muted);font-weight:400}
.rowlink{cursor:pointer}
.list tbody tr.rowlink:hover td,.list.sortable tbody tr.rowlink:hover .dn{background:var(--hl)}
.pick{display:flex;gap:10px;align-items:flex-start;background:var(--hl);border-left:3px solid var(--accent);padding:9px 12px;margin:16px 0 4px}
.pick .i16{flex:none;margin-top:4px;fill:var(--accent-ink)}
.sortable th{cursor:pointer;user-select:none}.sortable th:hover{background:var(--line2)}
.sortable th.asc:after{content:" ▲";font-size:9px}.sortable th.desc:after{content:" ▼";font-size:9px}
.sort{display:inline;background:none;border:0;padding:0;margin:0;font:inherit;color:inherit;text-align:inherit;line-height:inherit;cursor:pointer}
.sort:focus-visible{outline:2px solid var(--accent-ink);outline-offset:2px}
/* keep the designation visible while scrolling wide tables sideways */
.list.sortable th:first-child,.list.sortable .dn{position:sticky;left:0;z-index:1;box-shadow:1px 0 0 var(--line)}
.list.sortable .dn{background:var(--panel)}.list.sortable tbody tr:nth-child(even) .dn{background:var(--stripe)}
.list.sortable th:first-child{z-index:2}
.narrow{max-width:560px}
.tbl-tools{display:flex;flex-wrap:wrap;align-items:center;gap:12px;margin-top:14px}
.tfilter{padding:6px 9px;border:1px solid var(--line);border-radius:3px;width:240px;background:var(--panel);color:var(--text)}
.cols2{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:22px;align-items:start}
.cols2>div>h2:first-child{margin-top:20px}
.cols2>div{min-width:0}

/* calculator / forms */
.calc-body{padding:12px}
.frm{display:flex;flex-wrap:wrap;gap:12px;align-items:flex-end;margin-bottom:10px}
.frm label,.grid3 label{display:block;font-size:13px;color:var(--muted)}
.frm label input,.frm label select,.grid3 label input{display:block;margin-top:3px}
input[type=number],input[type=search],select{max-width:100%;padding:6px 8px;border:1px solid var(--line);border-radius:3px;font-size:14px;background:var(--panel);color:var(--text);font-family:inherit}
.frm input[type=number]{width:110px}
.grid3{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px}
.grid3 input{width:100%}
.calc-out table{margin-top:4px}.calc-out .big{font-size:18px;font-weight:600}
fieldset{border:1px solid var(--line);border-radius:3px;margin:0 0 12px;padding:8px 12px;min-width:0}
legend{font-size:13px;color:var(--muted);padding:0 4px}
.chks{display:flex;flex-wrap:wrap;gap:4px 16px}.chk{font-size:14px;white-space:nowrap}
.finder .note{margin:6px 0 0}
.ok{color:var(--ok);font-weight:600}.fail{color:var(--fail);font-weight:600}
.best{background:var(--hl)!important;font-weight:600}
.cmp th{min-width:110px}.cmp td{text-align:right}.cmp td:first-child,.cmp th:first-child{text-align:left}
.cmp .x{border:0;background:none;color:var(--muted);cursor:pointer;font-size:16px;line-height:1}
.overlay{background:#fff;border:1px solid var(--line);margin:12px 0}.overlay svg{display:block;width:100%;height:auto;max-height:420px}
.legend{display:flex;flex-wrap:wrap;gap:14px;font-size:13px;padding:6px 10px;color:var(--text)}.legend i{display:inline-block;width:14px;height:4px;margin-right:5px;vertical-align:middle}
.overlay .legend{color:#333}

/* (i) tooltips */
.tip{position:relative;display:inline-flex;align-items:center;justify-content:center;width:15px;height:15px;border-radius:50%;
  background:var(--brand2);color:#fff;font:italic bold 11px Georgia,serif;cursor:help;vertical-align:1px;margin-left:3px;user-select:none}
.tip.static{cursor:default}
.tip-box{display:none;position:absolute;top:calc(100% + 6px);left:0;z-index:80;width:min(340px,86vw);padding:9px 11px;background:var(--panel);
  color:var(--text);border:1px solid var(--line);border-radius:3px;box-shadow:0 4px 14px rgba(0,0,0,.18);font:normal 13px/1.45 "Segoe UI",Arial,sans-serif;
  text-align:left;white-space:normal;cursor:auto}
.tip:hover .tip-box,.tip:focus .tip-box,.tip:focus-within .tip-box{display:block}
.tip:focus{outline:2px solid var(--accent);outline-offset:1px}
th .tip-box{font-weight:normal}

/* capacity chart, length/mass */
.chartfig{margin:10px 0 0;border:1px solid var(--line);background:var(--panel);padding:6px}
.chart{display:block;width:100%;height:auto;font-size:10px;fill:var(--text)}
.chart .g{stroke:var(--line2);stroke-width:1}.chart .ax-m{fill:var(--link)}.chart .ax-n{fill:var(--muted)}
.seg{display:block;width:100%;max-width:360px;margin:10px 0}
.seg line{stroke:var(--text)}.seg rect{fill:var(--panel);stroke:var(--link)}.seg text{fill:var(--link)}.seg .lbl{fill:var(--muted)}
.seg .load{stroke:var(--accent);stroke-width:2}.seg .load-h{fill:var(--accent)}
/* beam calculator diagrams */
.bmd{margin:10px 0 0}.bmd figcaption{font-size:13px;color:var(--muted)}.bmd svg{display:block;width:100%;height:auto;max-width:560px}
.bmd .ax{stroke:var(--muted);stroke-width:1}
.bmd .bm-m{fill:rgba(26,95,180,.16);stroke:var(--link);stroke-width:1.5}
.bmd .bm-v{fill:rgba(231,111,36,.16);stroke:var(--accent);stroke-width:1.5}
.bmd .bm-y{fill:rgba(46,125,50,.16);stroke:var(--ok);stroke-width:1.5}
.bm-pts input{width:100%}
.lm{margin:16px 0}.lm .frm{margin:0;align-items:center}.lm output{font-size:15px}

/* misc content */
.sibs{display:flex;flex-wrap:wrap;gap:6px}
.sibs a{border:1px solid var(--line);padding:3px 8px;border-radius:3px;font-size:13px;background:var(--panel)}
.sibs a.on{background:var(--brand2);color:#fff;border-color:var(--brand2)}
.stds{padding-left:18px}.stds li{margin-bottom:8px}.stds span{font-size:13px;color:var(--muted)}
.std h2{font-size:18px}.std-t{font-weight:600;margin-top:-4px}
.links{padding-left:18px}.links li{margin-bottom:6px}
.faq dt{font-weight:600;margin-top:12px}.faq dd{margin:4px 0 0 0;color:var(--text)}
.hero{border-bottom:1px solid var(--line);padding-bottom:14px;margin-bottom:6px}
.hero h1{font-size:28px}.hero p{font-size:16px;max-width:820px}
.hero-links{display:flex;flex-wrap:wrap;gap:8px}
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));gap:12px}
.card{display:flex;gap:12px;border:1px solid var(--line);border-radius:3px;padding:12px;color:var(--text);background:var(--panel)}
.card:hover{border-color:var(--brand2);text-decoration:none;background:var(--th)}
.card strong{display:block;color:var(--link)}.card small{display:block;color:var(--muted)}.card em{display:block;font-style:normal;font-size:13px;margin-top:4px}
.feat{margin-top:20px}.feat .links{padding:10px 12px 4px 28px;margin:0}

/* footer */
.ftr{background:#0f1f33;color:#b9c4d2;font-size:13px;padding:26px 0 18px}
.ftr a{color:#d6dde6}.ftr h3{color:#fff;font-size:14px;margin:0 0 8px}
.f-cols{display:grid;grid-template-columns:repeat(4,1fr);gap:20px}
.ftr ul{list-style:none;margin:0;padding:0}.ftr li{margin-bottom:4px}
.disc{border-top:1px solid #2a3b52;margin-top:18px;padding-top:12px;color:#8f9cad}.copy{color:#8f9cad}

/* responsive */
@media (max-width:1000px){
  .layout{grid-template-columns:minmax(0,1fr)}
  .side{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:16px}.side>*{margin:0}
  .ad-tall{display:none}.sticky{position:static}
  .mm{width:min(760px,92vw)}
}
@media (max-width:760px){
  body{font-size:15px}
  .topbar .wrap>span:first-child{display:none}.topbar .wrap{justify-content:flex-end}
  .hdr>.wrap{flex-wrap:wrap;gap:10px}
  .search{order:3;flex-basis:100%;max-width:none}
  .menu-btn{display:block;margin-left:auto}
  .nav{display:none}.nav.open{display:block}
  .nav-l{flex-direction:column;width:100%}.mm{position:static;display:none!important}
  .content{padding:14px 14px 20px}
  .cols2,.fam-intro,.f-cols,.grid3{grid-template-columns:minmax(0,1fr)}
  .side{grid-template-columns:minmax(0,1fr)}
  select{max-width:100%}
  .content table:not(.props){display:block;overflow-x:auto;max-width:100%}
  .ad-sidebar{width:100%}
  h1{font-size:22px}.hero h1{font-size:23px}
  .sheet-full{display:block}
  .sibs a{padding:7px 10px}
  .pn a{display:inline-block;padding:8px 0}
  .tip::after{content:"";position:absolute;inset:-9px}
  .ftr li{margin-bottom:10px}
  .props{font-size:13px}.props th,.props td{padding:4px 5px}
  .props .sym{font-size:14px}.props .u{font-size:12px}
  .cap{font-size:12.5px}.cap th{white-space:normal}.cap th,.cap td{padding:4px 4px}
  .calc .frm input[type=number]{width:100%}
  /* 16px stops iOS Safari zooming the page when a field is focused */
  input[type=number],input[type=search],input[type=text],select,textarea,.search input{font-size:16px}
  /* reserve the cropped drawing's shape so the script that crops it can't shift the page */
  .sheet-wrap[style]{aspect-ratio:var(--crop-ar)}.sheet-wrap[style]>.sheet{height:100%}
}

/* print: drawing sheet on A4 landscape at true scale */
@media print{
  @page{size:A4 landscape;margin:0}
  body.print-sheet>*{display:none!important}
  body.print-sheet>.print-only{display:block!important}
  .print-only svg{width:297mm;height:210mm;display:block}
  body:not(.print-sheet) .topbar,body:not(.print-sheet) .hdr,body:not(.print-sheet) .ad,body:not(.print-sheet) .side,body:not(.print-sheet) .ftr,body:not(.print-sheet) .lb{display:none}
}