/* GravelCalc — builder's-merchant utility design system */

:root {
  --stone-900: #221f1b;
  --stone-800: #332e28;
  --stone-700: #4d443b;
  --stone-600: #6b5f53;
  --stone-500: #8a7c6d;
  --stone-300: #cabfae;
  --concrete-50: #faf8f4;
  --concrete-100: #f3efe6;
  --concrete-200: #e8e0d1;
  --white: #ffffff;
  --accent: #ff5a1f;
  --accent-dark: #d9490f;
  --accent-ink: #7a2c0c;
  --yellow: #f5b400;
  --good: #2f7d4f;
  --good-bg: #e8f4ec;
  --border: #ddd2bf;
  --radius-sm: 6px;
  --radius: 12px;
  --radius-lg: 18px;
  --shadow-sm: 0 1px 2px rgba(34, 31, 27, 0.06);
  --shadow: 0 2px 4px rgba(34, 31, 27, 0.05), 0 8px 24px rgba(34, 31, 27, 0.07);
  --font-head: "Archivo", "Arial Black", system-ui, sans-serif;
  --font-body: "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;
  --container: 1120px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font-body);
  color: var(--stone-800);
  background: var(--concrete-50);
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
  font-family: var(--font-head);
  color: var(--stone-900);
  line-height: 1.15;
  margin: 0 0 0.5em;
  letter-spacing: -0.01em;
}

h1 { font-size: clamp(1.9rem, 1.5rem + 1.8vw, 2.6rem); font-weight: 800; }
h2 { font-size: clamp(1.4rem, 1.2rem + 0.9vw, 1.85rem); font-weight: 800; }
h3 { font-size: 1.15rem; font-weight: 700; }

p { margin: 0 0 1em; color: var(--stone-700); }
a { color: var(--accent-dark); text-decoration-thickness: 1.5px; }
a:hover { color: var(--accent); }

.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 20px;
}

img, svg { max-width: 100%; }

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--white);
  border-bottom: 1px solid var(--border);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
  gap: 16px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 1.15rem;
  color: var(--stone-900);
  text-decoration: none;
  white-space: nowrap;
}

.logo:hover { color: var(--stone-900); }

.logo-mark {
  width: 30px;
  height: 30px;
  border-radius: 8px;
  background: var(--accent);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--white);
  font-weight: 800;
  font-size: 1rem;
  flex-shrink: 0;
}

nav.main-nav {
  display: flex;
  align-items: center;
  gap: 4px;
}

nav.main-nav a {
  color: var(--stone-700);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.92rem;
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  white-space: nowrap;
}

nav.main-nav a:hover { background: var(--concrete-100); color: var(--stone-900); }

.has-dropdown { position: relative; }
.dropdown {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 6px;
  min-width: 220px;
}
.has-dropdown:hover .dropdown,
.has-dropdown:focus-within .dropdown { display: block; }
.dropdown a { display: block; padding: 9px 12px; }

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  width: 40px;
  height: 40px;
  align-items: center;
  justify-content: center;
  cursor: pointer;
}
.nav-toggle svg { width: 20px; height: 20px; }

@media (max-width: 880px) {
  nav.main-nav {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--white);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    align-items: stretch;
    padding: 8px 12px 16px;
    gap: 0;
    box-shadow: var(--shadow);
  }
  nav.main-nav.open { display: flex; }
  nav.main-nav a { padding: 12px; }
  .has-dropdown .dropdown {
    display: block;
    position: static;
    box-shadow: none;
    border: none;
    padding-left: 10px;
    min-width: 0;
  }
  .nav-toggle { display: inline-flex; }
}

/* ---------- Breadcrumbs ---------- */
.breadcrumbs {
  font-size: 0.82rem;
  color: var(--stone-500);
  margin: 18px 0 6px;
}
.breadcrumbs a { color: var(--stone-500); text-decoration: none; }
.breadcrumbs a:hover { color: var(--accent-dark); }
.breadcrumbs .sep { margin: 0 6px; }

/* ---------- Hero ---------- */
.hero { padding: 6px 0 8px; }
.hero .lede {
  font-size: 1.1rem;
  color: var(--stone-700);
  max-width: 62ch;
}
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent-dark);
  background: #fff1e9;
  border: 1px solid #ffd9c2;
  padding: 4px 10px;
  border-radius: 999px;
  margin-bottom: 12px;
}

/* ---------- Trust row (above-the-fold hero badges) ---------- */
.trust-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  margin: 12px 0 2px;
}
.trust-row span {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--stone-600);
}
.trust-row span::before {
  content: "✓";
  color: var(--good);
  font-weight: 800;
}

/* ---------- Language switch ---------- */
.lang-switch {
  border: 1px solid var(--border) !important;
  border-radius: 999px !important;
  margin-left: 4px;
}
.lang-switch:hover { border-color: var(--accent) !important; }

/* ---------- Calculator card ---------- */
.calc-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  padding: 22px;
  margin: 18px 0 28px;
}

.calc-grid {
  display: grid;
  grid-template-columns: 1.15fr 1fr;
  gap: 26px;
  align-items: start;
}

@media (max-width: 760px) {
  .calc-grid { grid-template-columns: 1fr; }
}

.unit-toggle {
  display: inline-flex;
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 3px;
  background: var(--concrete-100);
  margin-bottom: 18px;
}
.unit-toggle button {
  border: none;
  background: transparent;
  padding: 7px 16px;
  border-radius: 999px;
  font-weight: 700;
  font-size: 0.85rem;
  color: var(--stone-600);
  cursor: pointer;
  font-family: var(--font-body);
}
.unit-toggle button.active {
  background: var(--stone-900);
  color: var(--white);
}

.field-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
  margin-bottom: 14px;
}
.field-row.single { grid-template-columns: 1fr; }

.field label {
  display: block;
  font-weight: 700;
  font-size: 0.84rem;
  color: var(--stone-800);
  margin-bottom: 6px;
}
.field .unit-tag {
  font-weight: 600;
  color: var(--stone-500);
  text-transform: lowercase;
}

.input-wrap { position: relative; }
.input-wrap input,
.input-wrap select {
  width: 100%;
  height: 48px;
  font-size: 1.05rem;
  font-family: var(--font-body);
  font-weight: 600;
  color: var(--stone-900);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0 44px 0 14px;
  background: var(--concrete-50);
  appearance: none;
}
.input-wrap input:focus,
.input-wrap select:focus {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
  border-color: var(--accent);
  background: var(--white);
}
.input-wrap .suffix {
  position: absolute;
  right: 14px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--stone-500);
  pointer-events: none;
}
select.plain-select { padding-right: 34px; }

.help-text { font-size: 0.8rem; color: var(--stone-500); margin: 10px 0 0; }

/* Results */
.results {
  background: var(--stone-900);
  background-image: radial-gradient(circle at 100% 0%, #3a332a 0%, var(--stone-900) 55%);
  border-radius: var(--radius);
  padding: 20px;
  min-height: 230px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 12px;
}
.results .results-label {
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--stone-300);
}
.result-stat {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  border-bottom: 1px solid rgba(255,255,255,0.1);
  padding-bottom: 10px;
}
.result-stat:last-child { border-bottom: none; padding-bottom: 0; }
.result-stat .rs-name { color: var(--stone-300); font-weight: 600; font-size: 0.9rem; }
.result-stat .rs-value {
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 1.7rem;
  color: var(--white);
  font-variant-numeric: tabular-nums;
}
.result-stat.primary .rs-value { color: var(--accent); font-size: 2.1rem; }
.result-stat .rs-unit { font-size: 0.95rem; color: var(--stone-300); font-weight: 700; margin-left: 4px; }

/* ---------- How it's calculated ---------- */
.formula-box {
  background: var(--concrete-100);
  border: 1px solid var(--border);
  border-left: 4px solid var(--accent);
  border-radius: var(--radius-sm);
  padding: 14px 16px;
  font-family: ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
  font-size: 0.88rem;
  color: var(--stone-800);
  overflow-x: auto;
  margin: 14px 0;
}

.block ul {
  margin: 0 0 1em;
  padding-left: 1.3em;
  color: var(--stone-700);
}
.block ul li { margin-bottom: 6px; }
.block ul li::marker { color: var(--accent-dark); }

section.block { padding: 26px 0; }
section.block.tight { padding: 14px 0 26px; }
.section-title { margin-bottom: 10px; }

/* ---------- FAQ ---------- */
.faq-item {
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--white);
  margin-bottom: 10px;
  overflow: hidden;
}
.faq-item summary {
  cursor: pointer;
  list-style: none;
  padding: 14px 16px;
  font-weight: 700;
  color: var(--stone-900);
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary h3 {
  margin: 0;
  font-family: inherit;
  font-size: inherit;
  font-weight: inherit;
  color: inherit;
}
.faq-item summary::after {
  content: "+";
  font-size: 1.4rem;
  color: var(--accent-dark);
  font-weight: 800;
  flex-shrink: 0;
}
.faq-item[open] summary::after { content: "\2212"; }
.faq-item .faq-answer { padding: 0 16px 16px; color: var(--stone-700); }

/* ---------- Related calculators ---------- */
.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 14px;
}
.related-card {
  display: block;
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  text-decoration: none;
  transition: border-color 0.15s, transform 0.15s;
}
.related-card:hover { border-color: var(--accent); transform: translateY(-2px); }
.related-card .rc-kicker {
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--accent-dark);
  margin-bottom: 6px;
}
.related-card h2 { margin-bottom: 4px; color: var(--stone-900); font-size: 1.02rem; }
.related-card p { margin: 0; font-size: 0.87rem; color: var(--stone-600); }

/* ---------- Hub grid (homepage) ---------- */
.hub-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 18px;
}
.hub-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 20px;
  text-decoration: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
  box-shadow: var(--shadow-sm);
}
.hub-card:hover { border-color: var(--accent); box-shadow: var(--shadow); }
.hub-card .hc-icon {
  width: 40px; height: 40px;
  border-radius: 10px;
  background: var(--concrete-100);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.3rem;
}
.hub-card h2 { color: var(--stone-900); margin: 4px 0 0; font-size: 1.02rem; }
.hub-card p { font-size: 0.88rem; margin: 0; color: var(--stone-600); }
.hub-card .hc-meta { font-size: 0.76rem; color: var(--stone-500); font-weight: 700; margin-top: auto; }

/* ---------- Guide content ---------- */
.guide-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  font-size: 0.92rem;
}
.guide-table th, .guide-table td {
  text-align: left;
  padding: 10px 14px;
  border-bottom: 1px solid var(--border);
}
.guide-table th {
  background: var(--concrete-100);
  font-family: var(--font-head);
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--stone-700);
}
.guide-table tr:last-child td { border-bottom: none; }
.table-wrap { overflow-x: auto; }

.callout {
  background: var(--good-bg);
  border: 1px solid #bfe1cb;
  border-left: 4px solid var(--good);
  border-radius: var(--radius-sm);
  padding: 14px 16px;
  margin: 16px 0;
  font-size: 0.92rem;
  color: var(--stone-800);
}

/* ---------- CTA band ---------- */
.cta-band {
  background: var(--stone-900);
  border-radius: var(--radius-lg);
  padding: 30px;
  text-align: center;
  margin: 30px 0;
}
.cta-band h2 { color: var(--white); }
.cta-band p { color: var(--stone-300); }
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--accent);
  color: var(--white);
  font-weight: 800;
  text-decoration: none;
  padding: 13px 24px;
  border-radius: 999px;
  font-size: 0.95rem;
  border: none;
  cursor: pointer;
}
.btn:hover { background: var(--accent-dark); color: var(--white); }

/* ---------- Footer ---------- */
footer.site-footer {
  background: var(--stone-900);
  color: var(--stone-300);
  margin-top: 40px;
  padding: 40px 0 24px;
}
footer.site-footer a { color: var(--stone-300); text-decoration: none; font-size: 0.9rem; }
footer.site-footer a:hover { color: var(--white); }
.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr repeat(3, 1fr);
  gap: 24px;
  padding-bottom: 24px;
  border-bottom: 1px solid rgba(255,255,255,0.1);
}
@media (max-width: 760px) {
  .footer-grid { grid-template-columns: 1fr 1fr; }
}
.footer-grid h4 {
  color: var(--white);
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 12px;
}
.footer-grid ul { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 8px; }
.footer-brand p { color: var(--stone-500); font-size: 0.85rem; }
.footer-bottom {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
  padding-top: 18px;
  font-size: 0.8rem;
  color: var(--stone-500);
}

.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--accent);
  color: var(--white);
  padding: 10px 16px;
  z-index: 100;
}
.skip-link:focus { left: 12px; top: 12px; }

@media (max-width: 500px) {
  .field-row { grid-template-columns: 1fr; }
}