/* Concrete Calculator — premium industrial design system (file:// safe: system fonts only) */
/* Redesign inspired by a clean corporate-technical utility look (pale slate
   background, white cards, deep teal actions, green active accents, centered
   hero, big rounded cards, pill links). Original implementation — no
   competitor text, content, or code copied. */
:root{
  --bg:#F8FAFC; --surface:#ffffff; --surface2:#F1F5F9; --line:#E2E8F0;
  --text:#0F172A; --muted:#475569; --brand:#0E7490; --brand2:#16A34A;
  --good:#2f9e44; --warn:#e03131; --radius:20px; --max:1080px;
  --font:system-ui,-apple-system,"Segoe UI",Roboto,Arial,sans-serif;
  --font-mono:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--text);font-family:var(--font);line-height:1.6}
a{color:var(--brand)}
.wrap{max-width:var(--max);margin:0 auto;padding:0 20px}
header.site{border-bottom:1px solid var(--line);background:#ffffff;position:sticky;top:0;z-index:10}
header.site .wrap{display:flex;align-items:center;gap:16px;flex-wrap:nowrap;padding-top:12px;padding-bottom:12px}
.logo{font-weight:800;font-size:20px;letter-spacing:.2px;text-decoration:none;color:var(--text);white-space:nowrap;flex-shrink:0}
.logo span{color:var(--brand2)}
nav.main{display:flex;gap:14px;flex-wrap:nowrap;font-size:14.5px;align-items:center;margin-left:auto;white-space:nowrap}
nav.main a{color:var(--muted);text-decoration:none;white-space:nowrap;padding:4px 2px}
nav.main a:hover{color:var(--text)}
nav.main a.active{color:var(--brand2);font-weight:700}
.hero{padding:44px 0 26px;text-align:center}
.hero h1{font-size:clamp(30px,5vw,48px);line-height:1.15;margin:0 0 10px;letter-spacing:-.5px}
.hero p.lede{font-size:18px;color:var(--muted);max-width:760px;margin:0 auto}
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:22px;margin:22px 0}
.card h2{margin-top:0;font-size:22px}
.card h2::before{content:"";display:inline-block;width:10px;height:10px;background:var(--text);border-radius:2px;margin-right:9px}
.grid2{display:grid;grid-template-columns:1fr 1fr;gap:16px}
@media(max-width:700px){.grid2{grid-template-columns:1fr}}
label{display:block;font-weight:600;margin:12px 0 4px}
input[type=number],select{width:100%;padding:11px 12px;border-radius:12px;border:1px solid var(--line);
  background:var(--surface2);color:var(--text);font-size:16px}
input[type=number]:focus,select:focus{outline:2px solid var(--brand);border-color:var(--brand)}
.hint{color:var(--muted);font-size:13px;margin-top:4px}
button.calc{background:var(--brand);color:#ffffff;border:0;padding:13px 22px;border-radius:12px;
  font-size:17px;font-weight:800;cursor:pointer;margin-top:16px;box-shadow:0 6px 16px rgba(14,116,144,.25)}
button.calc:hover{background:#155e75}
button.ghost{background:transparent;color:var(--muted);border:1px solid var(--line);padding:11px 18px;
  border-radius:12px;font-size:15px;cursor:pointer;margin-top:16px;margin-left:8px}
.results{display:none;margin-top:20px;border-top:1px solid var(--line);padding-top:16px}
.results.show{display:block;background:#F8FAFC;border:1px solid var(--line);border-left:4px solid var(--brand);border-radius:12px;padding:18px}
.big{font-size:clamp(30px,5vw,44px);font-weight:800;color:var(--brand);line-height:1.1;font-family:var(--font-mono)}
table{width:100%;border-collapse:collapse;margin:14px 0;font-size:15px}
th,td{border:1px solid var(--line);padding:9px 11px;text-align:left}
th{background:var(--surface2)}
.note{background:#F1F5F9;border:1px solid #E2E8F0;border-radius:10px;padding:13px 16px;color:var(--muted);font-size:14px}
.warn{background:#fff1f0;border:1px solid #f3b8ad;border-radius:10px;padding:13px 16px;font-size:14px}
.faq details{background:var(--surface);border:1px solid var(--line);border-radius:10px;padding:14px 18px;margin:10px 0}
.faq summary{font-weight:700;cursor:pointer}
footer.site{border-top:1px solid var(--line);background:var(--surface2);margin-top:40px;padding:32px 0 24px;color:var(--muted);font-size:14px}
footer.site a{color:var(--muted);text-decoration:none}
footer.site a:hover{color:var(--text);text-decoration:underline}
.foot-grid{display:grid;grid-template-columns:1.5fr 1fr 1fr;gap:28px}
.foot-brand{margin:0 0 8px}
.foot-brand a{font-weight:800;font-size:17px;color:var(--text)}
.foot-brand a span{color:var(--brand2)}
.foot-title{font-weight:800;font-size:13px;letter-spacing:.07em;text-transform:uppercase;color:var(--muted);margin:0 0 10px}
.foot-grid ul{list-style:none;margin:0;padding:0}
.foot-grid li{margin:5px 0}
.foot-grid p{margin:0 0 8px}
.foot-method{font-size:13px}
.foot-bottom{border-top:1px solid var(--line);margin-top:20px;padding-top:14px;font-size:13px}
.foot-bottom p{margin:0}
@media(max-width:700px){.foot-grid{grid-template-columns:1fr;gap:18px}}
.rel{display:flex;gap:10px;flex-wrap:wrap}
.rel a{background:#ffffff;border:1px solid #b9dbe3;border-radius:999px;padding:7px 14px;
  text-decoration:none;color:var(--brand);font-size:14px}
.rel a:hover{background:#f0fdfa;border-color:var(--brand)}
/* Entrance animation: pure CSS, always ends VISIBLE — never depends on JS.
   (The old JS-gated reveal could leave the whole page black if its trigger
   did not fire, so it was removed.) */
@keyframes riseIn{from{opacity:0;transform:translateY(14px)}to{opacity:1;transform:none}}
.reveal{animation:riseIn .5s ease both}
.reveal.in{opacity:1;transform:none}
/* 3D cube: a rotating 3 ft cube showing what a cubic yard is */
.cube-scene{width:180px;height:180px;margin:26px auto;perspective:700px}
.cube{width:100%;height:100%;position:relative;transform-style:preserve-3d;animation:spin 14s linear infinite}
.cube .face{position:absolute;inset:0;display:flex;align-items:center;justify-content:center;
  background:rgba(14,116,144,.08);border:2px solid var(--brand);font-weight:800;font-size:20px;color:var(--brand)}
.cube .front{transform:translateZ(90px)}
.cube .back{transform:rotateY(180deg) translateZ(90px)}
.cube .right{transform:rotateY(90deg) translateZ(90px)}
.cube .left{transform:rotateY(-90deg) translateZ(90px)}
.cube .top{transform:rotateX(90deg) translateZ(90px)}
.cube .bottom{transform:rotateX(-90deg) translateZ(90px)}
@keyframes spin{from{transform:rotateX(-18deg) rotateY(0)}to{transform:rotateX(-18deg) rotateY(360deg)}}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .reveal{opacity:1;transform:none;transition:none;animation:none}
  .cube{animation:none}
}
@media(max-width:520px){.hero{padding:30px 0 18px}.card{padding:16px}table{display:block;overflow-x:auto}}

/* ---- polish pass: hover lift, measurement diagram ---- */
.card{transition:box-shadow .25s ease,transform .25s ease}
.card:hover{box-shadow:0 10px 30px rgba(15,23,42,.08)}
button.calc:active{transform:scale(.98)}
.diagram{position:relative;border:2px solid var(--brand);border-radius:10px;height:130px;margin:16px 0;background:rgba(14,116,144,.06)}
.diagram span{position:absolute;font-weight:700;color:var(--brand);font-size:14px}
.diagram .d-len{top:8px;left:50%;transform:translateX(-50%)}
.diagram .d-wid{left:10px;top:50%;transform:translateY(-50%)}
.diagram .d-dep{right:10px;top:50%;transform:translateY(-50%)}
.diagram .d-form{bottom:10px;left:10px;right:10px;text-align:center;color:var(--muted);font-size:13px;font-weight:400}
button[data-preset]{background:var(--surface2);color:var(--text);border:1px solid var(--line);border-radius:999px;padding:7px 14px;cursor:pointer;font-size:14px;margin:2px}
button[data-preset]:hover{border-color:var(--brand);color:var(--brand2)}

/* ---- v12: grouped header nav + hero photos ---- */
.header-row{justify-content:space-between}
.nav-toggle{position:absolute;opacity:0;width:1px;height:1px;overflow:hidden}
.nav-burger{display:none;cursor:pointer;font-weight:700;color:var(--text);
  border:1px solid var(--line);border-radius:10px;padding:8px 12px;background:var(--surface)}
nav.main{align-items:center}
.nav-drop{position:relative}
.nav-drop summary{list-style:none;cursor:pointer;color:var(--muted);font-size:15px;padding:4px 2px}
.nav-drop summary::-webkit-details-marker{display:none}
.nav-drop summary::after{content:" \25be"}
.nav-drop summary:hover,.nav-drop[open] summary{color:var(--text)}
.drop-menu{position:absolute;top:calc(100% + 10px);right:0;z-index:20;min-width:230px;
  background:#ffffff;border:1px solid var(--line);border-radius:14px;
  box-shadow:0 14px 34px rgba(15,23,42,.14);padding:8px;display:flex;flex-direction:column}
.drop-menu a{padding:8px 12px;border-radius:8px}
.drop-menu a:hover{background:var(--surface2)}
.hero-figure{margin:4px 0 0}
.hero-img{width:100%;height:auto;display:block;border-radius:var(--radius);border:1px solid var(--line)}
.hero-figure figcaption{color:var(--muted);font-size:13px;margin-top:6px;text-align:center}

/* ---- v13: single-line header on desktop ---- */
/* Logo + short links + one dropdown must fit on ONE row. flex-wrap:nowrap
   on the header row is the fix: the old wrap let the long 16-name nav
   spill onto 2-3 lines. Short visible labels keep the row narrow;
   the full names stay in the dropdown, chooser table and page titles. */
header.site .wrap{flex-wrap:nowrap}
.header-row{justify-content:space-between;flex-wrap:nowrap}
nav.main{flex-wrap:nowrap}
.nav-drop summary{font-size:14.5px;white-space:nowrap}
@media(max-width:1080px){
  header.site .wrap{gap:12px}
  nav.main{gap:11px;font-size:14px}
  .logo{font-size:19px}
  .nav-drop summary{font-size:14px}
}
.nav-drop summary:focus-visible,.nav-burger:focus-visible{outline:2px solid var(--brand);outline-offset:2px;border-radius:8px}
@media(max-width:900px){
  /* Mobile/tablet: header BAR itself stays one line (logo + burger);
     the menu only drops below when the burger is tapped — standard
     professional behaviour, not a wrapped header. */
  .nav-burger{display:block;flex-shrink:0;white-space:nowrap}
  header.site .wrap{flex-wrap:wrap;row-gap:10px}
  nav.main{display:none;flex-direction:column;align-items:stretch;width:100%;gap:2px;padding-bottom:6px;flex-wrap:nowrap;white-space:normal}
  nav.main a{white-space:normal}
  #nav-toggle:checked ~ nav.main{display:flex}
  .nav-drop summary{padding:8px 2px}
  .drop-menu{position:static;box-shadow:none;border:0;padding:0 0 0 14px;min-width:0}
}