/* Concrete & material calculators — mobile-first, no frameworks */
:root {
  --ink: #1c1a17;
  --muted: #6b625a;
  --bg: #faf8f4;
  --card: #ffffff;
  --accent: #7a4a1e;
  --accent-soft: #f3e7d7;
  --line: #e6ded2;
  --good: #2e7d32;
  --warn-bg: #fff4e0;
  --radius: 12px;
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--bg); color: var(--ink);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.6; font-size: 1.02rem;
}
main { max-width: 46rem; margin: 0 auto; padding: 1rem 1.1rem 4rem; }
header.site { background: #241c12; color: #f7f1e6; padding: 1.6rem 1.1rem 1.2rem; }
header.site .wrap { max-width: 46rem; margin: 0 auto; }
header.site h1 { margin: 0 0 .3rem; font-size: 1.55rem; line-height: 1.25; }
header.site p { margin: 0; color: #d9cdb8; font-size: .98rem; }
nav.tools { display: flex; gap: .5rem; flex-wrap: wrap; margin: 1rem 0 0; }
nav.tools a {
  color: #f7f1e6; text-decoration: none; font-size: .9rem;
  border: 1px solid #6b5a43; border-radius: 999px; padding: .3rem .8rem;
}
nav.tools a[aria-current="page"] { background: var(--accent); border-color: var(--accent); }
h1 { font-size: 1.6rem; line-height: 1.3; margin: 1.4rem 0 .6rem; }
h2 { font-size: 1.25rem; margin: 1.8rem 0 .5rem; }
h3 { font-size: 1.05rem; margin: 1.4rem 0 .4rem; }
p, li { color: var(--ink); }
.muted { color: var(--muted); font-size: .92rem; }
.card {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 1.1rem; margin: 1rem 0; box-shadow: 0 1px 2px rgba(0,0,0,.04);
}
label { display: block; font-weight: 600; font-size: .95rem; margin: .8rem 0 .25rem; }
input[type="number"], select {
  width: 100%; padding: .6rem .7rem; font-size: 1rem;
  border: 1px solid var(--line); border-radius: 8px; background: #fff; color: var(--ink);
}
input:focus, select:focus { outline: 2px solid var(--accent); outline-offset: 1px; }
.grid2 { display: grid; grid-template-columns: 1fr 1fr; gap: 0 .9rem; }
@media (max-width: 560px) { .grid2 { grid-template-columns: 1fr; } }
.check { display: flex; align-items: center; gap: .55rem; margin: .9rem 0; font-weight: 500; }
.check input { width: 1.15rem; height: 1.15rem; accent-color: var(--accent); }
button.calc {
  display: block; width: 100%; margin-top: .8rem; padding: .8rem;
  background: var(--accent); color: #fff; border: 0; border-radius: 10px;
  font-size: 1.05rem; font-weight: 700; cursor: pointer;
}
button.calc:hover { background: #66400f; }
.result {
  background: var(--accent-soft); border: 1px solid #e3cfae; border-radius: var(--radius);
  padding: 1.1rem; margin: 1rem 0;
}
.result .big { font-size: 1.7rem; font-weight: 800; margin: 0 0 .2rem; }
.result table { width: 100%; border-collapse: collapse; margin-top: .6rem; font-size: .95rem; }
.result td { padding: .35rem 0; border-top: 1px dashed #d9c9ac; }
.result td:last-child { text-align: right; font-weight: 700; }
.formula {
  background: #f2ede3; border-left: 4px solid var(--accent);
  padding: .6rem .9rem; font-size: .88rem; color: var(--muted); margin: .8rem 0;
}
.notice {
  background: var(--warn-bg); border: 1px solid #e8cf9e; border-radius: var(--radius);
  padding: .8rem 1rem; margin: 1rem 0; font-size: .94rem;
}
details.faq { border: 1px solid var(--line); border-radius: 8px; margin: .5rem 0; background: #fff; }
details.faq summary { padding: .7rem .9rem; cursor: pointer; font-weight: 600; }
details.faq div { padding: 0 .9rem .9rem; color: var(--ink); }
.affil {
  border: 1px dashed #c9b99b; border-radius: var(--radius);
  padding: 1rem; margin: 1.5rem 0; background: #fffdf8;
}
.affil h3 { margin-top: 0; }
.affil ul { margin: .4rem 0; padding-left: 1.2rem; }
.affil a { color: var(--accent); }
.guide-list { list-style: none; padding: 0; }
.guide-list li { margin: .5rem 0; }
.guide-list a { color: var(--accent); font-weight: 600; }
footer.site { border-top: 1px solid var(--line); padding: 1.5rem 1.1rem 2.5rem; }
footer.site .wrap { max-width: 46rem; margin: 0 auto; }
footer.site p { color: var(--muted); font-size: .85rem; }
.breadcrumb { font-size: .85rem; color: var(--muted); margin-bottom: .4rem; }
.breadcrumb a { color: var(--accent); }
.ad-slot { /* AD SLOT: insert display-ad code at deploy time */ }