/* fStructures — Structural Engineering Reference */

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --fs-iron:    #1c2430;
  --fs-steel:   #2e3f52;
  --fs-rust:    #c0511a;
  --fs-rust2:   #9e4115;
  --fs-amber:   #e07b2a;
  --fs-slate:   #4a5a6b;
  --fs-fog:     #eef1f4;
  --fs-paper:   #f7f8fa;
  --fs-white:   #ffffff;
  --fs-ink:     #1a2230;
  --fs-muted:   #5a6b7a;
  --fs-border:  #cdd5de;
  --fs-accent:  #d4602a;
  --fs-r:       4px;
  --fs-max:     1100px;
}

html { font-size: 16px; scroll-behavior: smooth; }

body {
  background: var(--fs-paper);
  color: var(--fs-ink);
  font-family: Georgia, 'Times New Roman', serif;
  line-height: 1.7;
}

a { color: var(--fs-rust); text-decoration: none; }
a:hover { text-decoration: underline; color: var(--fs-rust2); }

img { max-width: 100%; display: block; }

.fs-center { max-width: var(--fs-max); margin: 0 auto; padding: 0 24px; }

/* ---- Masthead ---- */
.fs-masthead {
  background: var(--fs-iron);
  border-bottom: 4px solid var(--fs-rust);
}
.fs-masthead-inner {
  max-width: var(--fs-max);
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: stretch;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0;
}
.fs-brand {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px 0;
  text-decoration: none;
}
.fs-brand-icon {
  width: 38px;
  height: 38px;
  background: var(--fs-rust);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  clip-path: polygon(0 0, 100% 0, 100% 72%, 50% 100%, 0 72%);
}
.fs-brand-icon svg { width: 20px; height: 20px; fill: var(--fs-white); }
.fs-brand-name {
  font-family: system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  font-size: 1.35rem;
  font-weight: 900;
  color: var(--fs-white);
  letter-spacing: -0.03em;
  line-height: 1;
}
.fs-brand-name span { color: var(--fs-amber); }
.fs-brand-sub {
  font-family: system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  font-size: 0.68rem;
  font-weight: 600;
  color: #7a9ab2;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-top: 3px;
}
.fs-brand:hover .fs-brand-name { text-decoration: none; }

.fs-mainnav {
  display: flex;
  align-items: center;
  gap: 2px;
}
.fs-mainnav a {
  font-family: system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  font-size: 0.82rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: #9ab4c8;
  padding: 8px 14px;
  border-bottom: 3px solid transparent;
  text-decoration: none;
  transition: color 0.14s, border-color 0.14s;
  align-self: stretch;
  display: flex;
  align-items: center;
}
.fs-mainnav a:hover,
.fs-mainnav a.fs-cur {
  color: var(--fs-white);
  border-bottom-color: var(--fs-rust);
  text-decoration: none;
}

/* ---- Banner ---- */
.fs-banner {
  background: linear-gradient(110deg, var(--fs-steel) 0%, #1e3348 60%, #2a2018 100%);
  padding: 52px 0 42px;
  position: relative;
  overflow: hidden;
}
.fs-banner::before {
  content: '';
  position: absolute;
  inset: 0;
  background: repeating-linear-gradient(
    90deg,
    transparent,
    transparent 79px,
    rgba(255,255,255,0.025) 79px,
    rgba(255,255,255,0.025) 80px
  );
  pointer-events: none;
}
.fs-banner-body {
  position: relative;
  display: flex;
  align-items: flex-start;
  gap: 48px;
  flex-wrap: wrap;
}
.fs-banner-text { flex: 1 1 340px; }
.fs-eyebrow {
  font-family: system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  font-size: 0.7rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--fs-amber);
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.fs-eyebrow::before {
  content: '';
  display: block;
  width: 24px;
  height: 2px;
  background: var(--fs-rust);
}
.fs-banner h1 {
  font-family: Georgia, 'Times New Roman', serif;
  font-size: clamp(1.6rem, 3.8vw, 2.6rem);
  font-weight: 700;
  color: var(--fs-white);
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin-bottom: 16px;
}
.fs-banner h1 em {
  font-style: italic;
  color: var(--fs-amber);
}
.fs-banner-lead {
  font-size: 1.0rem;
  color: #8aacbe;
  max-width: 500px;
  margin-bottom: 26px;
  line-height: 1.65;
}
.fs-cta-btn {
  display: inline-block;
  background: var(--fs-rust);
  color: var(--fs-white);
  font-family: system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  font-size: 0.88rem;
  font-weight: 700;
  padding: 11px 24px;
  border-radius: var(--fs-r);
  text-decoration: none;
  transition: background 0.15s;
}
.fs-cta-btn:hover { background: var(--fs-rust2); text-decoration: none; color: var(--fs-white); }

.fs-factbar {
  flex: 0 0 auto;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  align-content: start;
}
.fs-fact {
  background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.09);
  border-top: 3px solid var(--fs-rust);
  padding: 14px 16px;
  border-radius: var(--fs-r);
  min-width: 130px;
}
.fs-fact-val {
  font-family: system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  font-size: 1.55rem;
  font-weight: 900;
  color: var(--fs-white);
  line-height: 1;
  margin-bottom: 5px;
}
.fs-fact-lbl {
  font-family: system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: #7a9ab2;
}

/* ---- Tag strip ---- */
.fs-tagstrip {
  background: var(--fs-fog);
  border-bottom: 1px solid var(--fs-border);
  padding: 9px 0;
  overflow-x: auto;
}
.fs-tagstrip-inner {
  display: flex;
  align-items: center;
  gap: 7px;
  flex-wrap: nowrap;
  white-space: nowrap;
}
.fs-tag-head {
  font-family: system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  font-size: 0.7rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--fs-muted);
  margin-right: 4px;
  flex-shrink: 0;
}
.fs-tag {
  display: inline-block;
  padding: 3px 11px;
  background: var(--fs-white);
  border: 1px solid var(--fs-border);
  border-radius: 20px;
  font-family: system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--fs-muted);
  text-decoration: none;
  transition: background 0.12s, color 0.12s;
  flex-shrink: 0;
}
.fs-tag:hover {
  background: var(--fs-rust);
  color: var(--fs-white);
  border-color: var(--fs-rust);
  text-decoration: none;
}

/* ---- Main content area ---- */
.fs-body { padding: 44px 0 64px; }
.fs-layout {
  display: grid;
  grid-template-columns: 1fr 290px;
  gap: 44px;
  align-items: start;
}
@media (max-width: 820px) {
  .fs-layout { grid-template-columns: 1fr; }
  .fs-factbar { grid-template-columns: repeat(2, 1fr); }
}

/* ---- Section heading ---- */
.fs-section-hd {
  font-family: system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  font-size: 0.78rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--fs-muted);
  border-bottom: 2px solid var(--fs-border);
  padding-bottom: 8px;
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  gap: 10px;
}
.fs-section-hd::before {
  content: '';
  display: block;
  width: 16px;
  height: 3px;
  background: var(--fs-rust);
  border-radius: 2px;
  flex-shrink: 0;
}

/* ---- Article card grid ---- */
.fs-cardgrid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
}
@media (max-width: 600px) {
  .fs-cardgrid { grid-template-columns: 1fr; }
}
.fs-card {
  background: var(--fs-white);
  border: 1px solid var(--fs-border);
  border-radius: var(--fs-r);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: box-shadow 0.15s;
}
.fs-card:hover { box-shadow: 0 4px 16px rgba(28,36,48,0.1); }
.fs-card-band {
  height: 5px;
  background: var(--fs-rust);
}
.fs-card-body { padding: 16px 18px; flex: 1; }
.fs-card-cat {
  font-family: system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  font-size: 0.67rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--fs-rust);
  margin-bottom: 6px;
}
.fs-card-title {
  font-size: 1.0rem;
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 8px;
  color: var(--fs-iron);
}
.fs-card-title a { color: inherit; }
.fs-card-title a:hover { color: var(--fs-rust); text-decoration: none; }
.fs-card-blurb {
  font-family: system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  font-size: 0.85rem;
  color: var(--fs-muted);
  line-height: 1.55;
}
.fs-card-foot {
  padding: 10px 18px;
  border-top: 1px solid var(--fs-border);
  background: var(--fs-fog);
}
.fs-card-link {
  font-family: system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--fs-rust);
  text-decoration: none;
}
.fs-card-link:hover { text-decoration: underline; }

/* ---- Sidebar panels ---- */
.fs-panel {
  background: var(--fs-white);
  border: 1px solid var(--fs-border);
  border-radius: var(--fs-r);
  margin-bottom: 22px;
  overflow: hidden;
}
.fs-panel-hd {
  background: var(--fs-iron);
  color: var(--fs-white);
  font-family: system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  font-size: 0.72rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.09em;
  padding: 9px 16px;
}
.fs-panel-body { padding: 16px; }
.fs-panel-body p {
  font-family: system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  font-size: 0.86rem;
  color: var(--fs-muted);
  line-height: 1.55;
  margin-bottom: 10px;
}
.fs-panel-body p:last-child { margin-bottom: 0; }
.fs-panel-list { list-style: none; }
.fs-panel-list li {
  font-family: system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  font-size: 0.86rem;
  padding: 7px 0;
  border-bottom: 1px solid var(--fs-border);
  display: flex;
  align-items: flex-start;
  gap: 8px;
}
.fs-panel-list li:last-child { border-bottom: none; }
.fs-panel-list li::before {
  content: '\25B6';
  color: var(--fs-rust);
  font-size: 0.6rem;
  margin-top: 5px;
  flex-shrink: 0;
}
.fs-panel-list a { color: var(--fs-ink); font-size: 0.86rem; }
.fs-panel-list a:hover { color: var(--fs-rust); text-decoration: none; }

.fs-callout {
  background: #fff4ec;
  border: 1px solid #f0c9aa;
  border-left: 4px solid var(--fs-rust);
  border-radius: var(--fs-r);
  padding: 14px 16px;
  margin-bottom: 22px;
}
.fs-callout-lbl {
  font-family: system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  font-size: 0.68rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--fs-rust2);
  margin-bottom: 6px;
}
.fs-callout p {
  font-family: system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  font-size: 0.86rem;
  color: #6b3b1a;
  line-height: 1.55;
}

/* ---- Article page layout ---- */
.fs-article-shell {
  max-width: 760px;
  margin: 0 auto;
  padding: 48px 24px 80px;
}
.fs-article-shell .fs-back {
  font-family: system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  font-size: 0.82rem;
  color: var(--fs-muted);
  display: inline-flex;
  align-items: center;
  gap: 4px;
  margin-bottom: 22px;
}
.fs-article-shell .fs-back:hover { color: var(--fs-rust); text-decoration: none; }
.fs-art-kicker {
  font-family: system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  font-size: 0.7rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--fs-rust);
  margin-bottom: 10px;
}
.fs-article-shell h1 {
  font-size: clamp(1.55rem, 3.5vw, 2.3rem);
  font-weight: 700;
  color: var(--fs-iron);
  line-height: 1.22;
  letter-spacing: -0.02em;
  margin-bottom: 16px;
}
.fs-art-meta {
  font-family: system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  font-size: 0.82rem;
  color: var(--fs-muted);
  margin-bottom: 28px;
  padding-bottom: 22px;
  border-bottom: 2px solid var(--fs-border);
  display: flex;
  align-items: center;
  gap: 18px;
  flex-wrap: wrap;
}
.fs-art-meta .fs-badge {
  background: var(--fs-fog);
  border: 1px solid var(--fs-border);
  border-radius: 3px;
  padding: 2px 8px;
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--fs-slate);
}

/* ---- Article body ---- */
.fs-art-body h2 {
  font-size: 1.28rem;
  font-weight: 700;
  color: var(--fs-iron);
  margin: 36px 0 12px;
  padding-bottom: 6px;
  border-bottom: 1px solid var(--fs-border);
}
.fs-art-body h3 {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--fs-steel);
  margin: 24px 0 8px;
}
.fs-art-body p {
  margin-bottom: 18px;
  font-size: 1.0rem;
  line-height: 1.75;
  color: var(--fs-ink);
}
.fs-art-body ul,
.fs-art-body ol {
  margin: 0 0 18px 24px;
  font-size: 0.97rem;
  line-height: 1.72;
}
.fs-art-body li { margin-bottom: 6px; }
.fs-art-body strong { color: var(--fs-iron); }
.fs-art-body em { font-style: italic; }

.fs-info-box {
  background: var(--fs-fog);
  border: 1px solid var(--fs-border);
  border-left: 4px solid var(--fs-rust);
  border-radius: var(--fs-r);
  padding: 16px 20px;
  margin: 24px 0;
}
.fs-info-box p {
  margin-bottom: 0;
  font-size: 0.94rem;
  color: var(--fs-slate);
}

/* ---- Footer ---- */
.fs-footer {
  background: var(--fs-iron);
  padding: 34px 0 26px;
  margin-top: 40px;
}
.fs-footer-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
  margin-bottom: 18px;
  padding-bottom: 18px;
  border-bottom: 1px solid rgba(255,255,255,0.08);
}
.fs-footer-wordmark {
  font-family: system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  font-size: 1.1rem;
  font-weight: 900;
  color: var(--fs-white);
  letter-spacing: -0.02em;
}
.fs-footer-wordmark span { color: var(--fs-amber); }
.fs-footer-nav {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
}
.fs-footer-nav a {
  font-family: system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  font-size: 0.83rem;
  color: #7a9ab2;
  text-decoration: none;
}
.fs-footer-nav a:hover { color: var(--fs-white); text-decoration: none; }
.fs-footer-disc {
  font-family: system-ui, -apple-system, 'Segoe UI', Arial, sans-serif;
  font-size: 0.77rem;
  color: #4a6070;
  line-height: 1.6;
}

/* ---- latest.php wrapper ---- */
.fs-latest-grid { margin-top: 0; }

/* ---- Responsive tweaks ---- */
@media (max-width: 680px) {
  .fs-banner { padding: 36px 0 30px; }
  .fs-banner h1 { font-size: 1.55rem; }
  .fs-factbar { display: none; }
  .fs-masthead-inner { flex-direction: column; align-items: flex-start; }
  .fs-mainnav { overflow-x: auto; }
}