/* ===== RenoFig Design System — Engineering Blue + Dark Gray ===== */

/* ===== Reset & Base ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  font-size: 16px; line-height: 1.6; color: var(--text-primary); background: var(--bg-main);
  transition: background 0.2s, color 0.2s;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--accent-blue); text-decoration: none; }
a:hover { text-decoration: underline; }
ul, ol { padding-left: 1.25rem; }
button { cursor: pointer; font-family: inherit; }
input, select, textarea { font-family: inherit; font-size: inherit; }

/* ===== CSS Variables ===== */
:root.light {
  --bg-main: #ffffff;
  --bg-card: #f8fafc;
  --bg-section: #f1f5f9;
  --bg-hover: #e2e8f0;
  --bg-input: #ffffff;
  --text-primary: #0f172a;
  --text-secondary: #334155;
  --text-muted: #64748b;
  --border-color: #e2e8f0;
  --border-strong: #cbd5e1;
  --eng-blue: #1e3a5f;
  --eng-blue-dark: #15293d;
  --eng-blue-light: #2c5282;
  --accent-blue: #2563eb;
  --accent-blue-hover: #1d4ed8;
  --gray-dark: #1e293b;
  --gray-medium: #475569;
  --success: #15803d;
  --success-light: #f0fdf4;
  --warning: #b45309;
  --warning-light: #fffbeb;
  --danger: #dc2626;
  --danger-light: #fef2f2;
  --shadow-sm: 0 1px 2px rgba(15,23,42,0.05);
  --shadow-md: 0 4px 12px rgba(15,23,42,0.08);
  --shadow-lg: 0 8px 24px rgba(15,23,42,0.12);
  --radius: 8px;
  --radius-lg: 12px;
}
:root.dark {
  --bg-main: #0f172a;
  --bg-card: #1e293b;
  --bg-section: #1a2332;
  --bg-hover: #334155;
  --bg-input: #1e293b;
  --text-primary: #f1f5f9;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;
  --border-color: #334155;
  --border-strong: #475569;
  --eng-blue: #3b82f6;
  --eng-blue-dark: #2563eb;
  --eng-blue-light: #60a5fa;
  --accent-blue: #60a5fa;
  --accent-blue-hover: #93c5fd;
  --gray-dark: #f1f5f9;
  --gray-medium: #cbd5e1;
  --success: #4ade80;
  --success-light: #052e16;
  --warning: #fbbf24;
  --warning-light: #422006;
  --danger: #f87171;
  --danger-light: #450a0a;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.2);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.3);
  --shadow-lg: 0 8px 24px rgba(0,0,0,0.4);
}

/* ===== Layout ===== */
.container { max-width: 1200px; margin: 0 auto; padding: 0 1.25rem; }
.main-content { padding: 1.5rem 0 3rem; min-height: 60vh; }

/* ===== Typography ===== */
h1 { font-size: 1.85rem; font-weight: 800; color: var(--text-primary); line-height: 1.25; margin-bottom: 0.75rem; }
h2 { font-size: 1.45rem; font-weight: 700; color: var(--text-primary); margin: 1.75rem 0 0.75rem; }
h3 { font-size: 1.15rem; font-weight: 700; color: var(--text-primary); margin: 1.25rem 0 0.5rem; }
h4 { font-size: 1rem; font-weight: 600; color: var(--text-secondary); margin: 1rem 0 0.4rem; }
p { color: var(--text-secondary); margin-bottom: 0.75rem; }
.lead { font-size: 1.1rem; color: var(--text-secondary); margin-bottom: 1rem; }

/* ===== Header ===== */
.site-header {
  background: var(--eng-blue); color: #fff; position: sticky; top: 0; z-index: 100;
  box-shadow: var(--shadow-md);
}
.header-inner {
  max-width: 1200px; margin: 0 auto; padding: 0 1.25rem;
  display: flex; align-items: center; justify-content: space-between; height: 60px;
}
.header-logo { display: flex; align-items: center; gap: 0.5rem; text-decoration: none; color: #fff; }
.header-logo img { height: 32px; width: 32px; }
.header-logo .logo-text { font-size: 1.25rem; font-weight: 800; letter-spacing: -0.02em; }
.main-nav { display: flex; align-items: center; gap: 0.25rem; }
.nav-dropdown { position: relative; }
.nav-dropdown > button {
  background: none; border: none; color: rgba(255,255,255,0.9); font-size: 0.9rem; font-weight: 600;
  padding: 0.5rem 0.875rem; border-radius: var(--radius); transition: background 0.15s;
  display: flex; align-items: center; gap: 0.25rem;
}
.nav-dropdown > button:hover { background: rgba(255,255,255,0.12); }
.nav-dropdown > button::after { content: '▾'; font-size: 0.7rem; opacity: 0.7; }
.nav-menu {
  position: absolute; top: 100%; left: 0; min-width: 260px; background: var(--bg-main);
  border: 1px solid var(--border-color); border-radius: var(--radius); box-shadow: var(--shadow-lg);
  padding: 0.5rem; display: none; flex-direction: column; gap: 0.125rem;
}
.nav-dropdown:hover .nav-menu, .nav-dropdown:focus-within .nav-menu { display: flex; }
.nav-menu-section-label { font-size: 0.7rem; text-transform: uppercase; letter-spacing: 0.06em; color: var(--text-muted); padding: 0.5rem 0.75rem 0.25rem; font-weight: 700; }
.nav-menu a { color: var(--text-primary); padding: 0.4rem 0.75rem; border-radius: var(--radius); font-size: 0.88rem; font-weight: 500; }
.nav-menu a:hover { background: var(--bg-hover); text-decoration: none; }
.header-right { display: flex; align-items: center; gap: 0.75rem; }
.darkmode-toggle {
  background: rgba(255,255,255,0.12); border: none; color: #fff; width: 36px; height: 36px;
  border-radius: var(--radius); display: flex; align-items: center; justify-content: center; font-size: 1.1rem;
  transition: background 0.15s;
}
.darkmode-toggle:hover { background: rgba(255,255,255,0.22); }
.mobile-menu-btn { display: none; background: none; border: none; color: #fff; font-size: 1.5rem; padding: 0.25rem; }

/* ===== Mobile Nav ===== */
.mobile-nav { display: none; background: var(--bg-main); border-bottom: 1px solid var(--border-color); padding: 0.5rem 0; }
.mobile-nav.open { display: block; }
.mobile-nav-section-label { font-size: 0.7rem; text-transform: uppercase; letter-spacing: 0.06em; color: var(--text-muted); padding: 0.5rem 1.25rem 0.15rem; font-weight: 700; }
.mobile-nav a { display: block; padding: 0.5rem 1.25rem; color: var(--text-primary); font-size: 0.9rem; font-weight: 500; }
.mobile-nav a:hover { background: var(--bg-hover); text-decoration: none; }

/* ===== Footer ===== */
.site-footer { background: var(--eng-blue-dark); color: rgba(255,255,255,0.8); padding: 2.5rem 0 1.5rem; margin-top: 2rem; }
.footer-inner { max-width: 1200px; margin: 0 auto; padding: 0 1.25rem; }
.footer-col-group { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 1.5rem; margin-bottom: 2rem; }
.footer-col h3 { color: #fff; font-size: 0.85rem; text-transform: uppercase; letter-spacing: 0.06em; margin-bottom: 0.75rem; }
.footer-col a { display: block; color: rgba(255,255,255,0.7); font-size: 0.85rem; padding: 0.2rem 0; }
.footer-col a:hover { color: #fff; text-decoration: underline; }
.footer-compliance { border-top: 1px solid rgba(255,255,255,0.15); padding-top: 1.25rem; margin-top: 1rem; }
.footer-compliance p { color: rgba(255,255,255,0.6); font-size: 0.78rem; line-height: 1.5; }
.footer-copyright { text-align: center; padding-top: 1rem; border-top: 1px solid rgba(255,255,255,0.15); margin-top: 1rem; }
.footer-copyright p { color: rgba(255,255,255,0.5); font-size: 0.8rem; }

/* ===== Breadcrumb ===== */
.breadcrumb-nav { display: flex; align-items: center; gap: 0.4rem; font-size: 0.82rem; color: var(--text-muted); margin-bottom: 1rem; flex-wrap: wrap; }
.breadcrumb-nav a { color: var(--accent-blue); }
.breadcrumb-separator { color: var(--text-muted); }
.breadcrumb-current { color: var(--text-secondary); font-weight: 600; }

/* ===== Page Header ===== */
.page-header { background: var(--bg-section); border-radius: var(--radius-lg); padding: 1.75rem; margin-bottom: 1.5rem; border: 1px solid var(--border-color); }
.page-header h1 { margin-bottom: 0.5rem; }
.page-meta { display: flex; flex-wrap: wrap; gap: 1rem; font-size: 0.8rem; color: var(--text-muted); margin-top: 0.75rem; }
.page-meta span { display: inline-flex; align-items: center; gap: 0.25rem; }

/* ===== Calculator ===== */
.calc-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 1.5rem; margin-bottom: 1.5rem; }
.calc-panel { background: var(--bg-card); border: 1px solid var(--border-color); border-radius: var(--radius-lg); padding: 1.5rem; }
.calc-panel h2 { margin-top: 0; font-size: 1.2rem; color: var(--eng-blue); }
.input-group { margin-bottom: 1rem; }
.input-group label { display: block; font-size: 0.85rem; font-weight: 600; color: var(--text-secondary); margin-bottom: 0.3rem; }
.input-group input, .input-group select {
  width: 100%; padding: 0.625rem 0.75rem; border: 1px solid var(--border-strong); border-radius: var(--radius);
  background: var(--bg-input); color: var(--text-primary); font-size: 0.95rem; transition: border-color 0.15s, box-shadow 0.15s;
}
.input-group input:focus, .input-group select:focus { outline: none; border-color: var(--accent-blue); box-shadow: 0 0 0 3px rgba(37,99,235,0.12); }
.input-hint { font-size: 0.75rem; color: var(--text-muted); margin-top: 0.2rem; }
.scenario-btns { display: flex; flex-wrap: wrap; gap: 0.5rem; margin-bottom: 1rem; }
.scenario-btn { background: var(--bg-section); border: 2px solid var(--border-color); border-radius: var(--radius); padding: 0.5rem 1rem; font-size: 0.85rem; font-weight: 600; color: var(--text-secondary); transition: all 0.15s; }
.scenario-btn:hover { border-color: var(--accent-blue); color: var(--accent-blue); }
.scenario-btn.active { background: var(--eng-blue); border-color: var(--eng-blue); color: #fff; }
.calc-btn {
  width: 100%; background: var(--accent-blue); color: #fff; border: none; border-radius: var(--radius);
  padding: 0.75rem; font-size: 1rem; font-weight: 700; transition: background 0.15s; margin-top: 0.5rem;
}
.calc-btn:hover { background: var(--accent-blue-hover); }
.result-item { display: flex; justify-content: space-between; align-items: center; padding: 0.6rem 0; border-bottom: 1px solid var(--border-color); }
.result-item:last-child { border-bottom: none; }
.result-label { font-size: 0.88rem; color: var(--text-secondary); font-weight: 500; }
.result-value { font-size: 1.05rem; font-weight: 700; color: var(--text-primary); }
.result-highlight { background: var(--success-light); border-radius: var(--radius); padding: 0.75rem 1rem; margin-top: 0.5rem; }
.result-highlight .result-label { color: var(--success); font-weight: 700; }
.result-highlight .result-value { font-size: 1.4rem; color: var(--success); }
.calc-disclaimer { font-size: 0.75rem; color: var(--text-muted); margin-top: 0.75rem; line-height: 1.4; }
.calc-actions { display: flex; gap: 0.5rem; margin-top: 1rem; }
.calc-actions button { flex: 1; padding: 0.5rem; border: 1px solid var(--border-strong); border-radius: var(--radius); background: var(--bg-main); color: var(--text-secondary); font-size: 0.82rem; font-weight: 600; transition: all 0.15s; }
.calc-actions button:hover { border-color: var(--accent-blue); color: var(--accent-blue); }

/* ===== Collapsible SEO (details/summary) ===== */
details.seo-panel { background: var(--bg-card); border: 1px solid var(--border-color); border-radius: var(--radius-lg); margin-bottom: 0.75rem; overflow: hidden; }
details.seo-panel summary {
  padding: 1rem 1.25rem; font-size: 1.05rem; font-weight: 700; color: var(--eng-blue); cursor: pointer;
  display: flex; align-items: center; justify-content: space-between; list-style: none; transition: background 0.15s;
}
details.seo-panel summary::-webkit-details-marker { display: none; }
details.seo-panel summary::after { content: '▸'; font-size: 0.9rem; color: var(--text-muted); transition: transform 0.2s; }
details.seo-panel[open] summary::after { transform: rotate(90deg); }
details.seo-panel summary:hover { background: var(--bg-hover); }
details.seo-panel .panel-content { padding: 0 1.25rem 1.25rem; }
details.seo-panel .panel-content h3 { font-size: 1rem; color: var(--text-primary); margin-top: 1rem; }
details.seo-panel .panel-content p { font-size: 0.9rem; }
details.seo-panel .panel-content ul { font-size: 0.9rem; color: var(--text-secondary); }
details.seo-panel .panel-content li { margin-bottom: 0.3rem; }

/* ===== Content Section ===== */
.content-section { background: var(--bg-card); border: 1px solid var(--border-color); border-radius: var(--radius-lg); padding: 1.75rem; margin-bottom: 1.25rem; }
.content-section h2 { margin-top: 0; }
.content-section h3 { color: var(--eng-blue); }
.content-section p, .content-section li { font-size: 0.92rem; line-height: 1.7; }

/* ===== FAQ ===== */
.faq-section { margin-bottom: 1.25rem; }
.faq-section > h2 { margin-bottom: 1rem; }
.faq-item { background: var(--bg-card); border: 1px solid var(--border-color); border-radius: var(--radius); margin-bottom: 0.5rem; overflow: hidden; }
.faq-question { width: 100%; text-align: left; background: none; border: none; padding: 1rem 1.25rem; font-size: 0.95rem; font-weight: 600; color: var(--text-primary); display: flex; justify-content: space-between; align-items: center; }
.faq-question:hover { background: var(--bg-hover); }
.faq-question::after { content: '+'; font-size: 1.2rem; color: var(--text-muted); transition: transform 0.2s; }
.faq-item.open .faq-question::after { transform: rotate(45deg); }
.faq-answer { display: none; padding: 0 1.25rem 1rem; font-size: 0.88rem; color: var(--text-secondary); line-height: 1.6; }
.faq-item.open .faq-answer { display: block; }

/* ===== Tables ===== */
table { width: 100%; border-collapse: collapse; margin: 1rem 0; font-size: 0.88rem; }
th, td { padding: 0.625rem 0.75rem; text-align: left; border: 1px solid var(--border-color); }
th { background: var(--bg-section); font-weight: 700; color: var(--text-primary); }
tbody tr:nth-child(even) { background: var(--bg-card); }
tbody tr:hover { background: var(--bg-hover); }

/* ===== Cards & Grids ===== */
.tool-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 1rem; margin: 1.25rem 0; }
.tool-card { display: flex; flex-direction: column; background: var(--bg-card); border: 1px solid var(--border-color); border-radius: var(--radius-lg); padding: 1.25rem; text-decoration: none; color: inherit; transition: border-color 0.15s, box-shadow 0.15s, transform 0.15s; }
.tool-card:hover { border-color: var(--accent-blue); box-shadow: var(--shadow-md); transform: translateY(-2px); text-decoration: none; }
.tool-card .tool-icon { font-size: 1.75rem; margin-bottom: 0.5rem; }
.tool-card .tool-title { font-size: 0.95rem; font-weight: 700; color: var(--text-primary); margin-bottom: 0.3rem; }
.tool-card .tool-desc { font-size: 0.8rem; color: var(--text-muted); line-height: 1.5; }

.blog-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 1.25rem; margin: 1.25rem 0; }
.blog-card { display: flex; flex-direction: column; background: var(--bg-card); border: 1px solid var(--border-color); border-radius: var(--radius-lg); padding: 1.25rem; text-decoration: none; color: inherit; transition: border-color 0.15s, box-shadow 0.15s, transform 0.15s; }
.blog-card:hover { border-color: var(--accent-blue); box-shadow: var(--shadow-md); transform: translateY(-2px); text-decoration: none; }
.blog-card .blog-category { font-size: 0.7rem; text-transform: uppercase; letter-spacing: 0.06em; color: var(--accent-blue); font-weight: 700; margin-bottom: 0.4rem; }
.blog-card h3 { font-size: 1rem; color: var(--text-primary); margin-bottom: 0.4rem; }
.blog-card p { font-size: 0.85rem; color: var(--text-muted); flex-grow: 1; }
.blog-card .blog-meta { font-size: 0.75rem; color: var(--text-muted); margin-top: 0.75rem; }

/* ===== Source Info ===== */
.source-info { background: var(--bg-section); border-radius: var(--radius); padding: 1rem 1.25rem; margin-top: 1.5rem; font-size: 0.8rem; color: var(--text-muted); }
.source-info strong { color: var(--text-secondary); }

/* ===== CTA ===== */
.cta-box { background: var(--eng-blue); color: #fff; border-radius: var(--radius-lg); padding: 1.5rem; text-align: center; margin: 1.5rem 0; }
.cta-box h3 { color: #fff; margin-top: 0; }
.cta-box p { color: rgba(255,255,255,0.85); }
.cta-box .cta-btn { display: inline-block; background: #fff; color: var(--eng-blue); padding: 0.625rem 1.5rem; border-radius: var(--radius); font-weight: 700; text-decoration: none; margin-top: 0.5rem; }
.cta-box .cta-btn:hover { background: var(--bg-hover); }

/* ===== Key Takeaways ===== */
.key-takeaways { background: var(--success-light); border-left: 4px solid var(--success); border-radius: var(--radius); padding: 1rem 1.25rem; margin: 1rem 0; }
.key-takeaways h3 { color: var(--success); margin-top: 0; }
.key-takeaways ul { color: var(--text-secondary); }
.key-takeaways li { margin-bottom: 0.3rem; font-size: 0.9rem; }

/* ===== Ad Blocks ===== */
.ad-block { background: var(--bg-section); border: 1px dashed var(--border-strong); border-radius: var(--radius); padding: 1rem; text-align: center; margin: 1.25rem 0; }
.ad-notice { font-size: 0.7rem; text-transform: uppercase; letter-spacing: 0.06em; color: var(--text-muted); }

/* ===== Article Content (Blog) ===== */
.article-content { font-size: 0.95rem; line-height: 1.75; color: var(--text-secondary); }
.article-content h2 { color: var(--eng-blue); margin-top: 2rem; font-size: 1.3rem; }
.article-content h3 { color: var(--text-primary); margin-top: 1.5rem; font-size: 1.08rem; }
.article-content p { margin-bottom: 1rem; }
.article-content ul, .article-content ol { margin: 0 0 1rem 1.25rem; color: var(--text-secondary); }
.article-content li { margin-bottom: 0.4rem; line-height: 1.7; }
.article-content strong { color: var(--text-primary); }
.article-content blockquote { border-left: 4px solid var(--accent-blue); background: var(--bg-section); padding: 0.75rem 1.25rem; margin: 1rem 0; border-radius: 0 var(--radius) var(--radius) 0; font-style: italic; color: var(--text-secondary); }
.article-content .case-study { background: var(--bg-card); border: 1px solid var(--border-color); border-radius: var(--radius-lg); padding: 1.25rem; margin: 1.25rem 0; }
.article-content .case-study h3 { color: var(--eng-blue); margin-top: 0; }
.article-meta-tags { display: flex; flex-wrap: wrap; gap: 0.5rem; margin: 0.75rem 0 1.25rem; }
.article-meta-tags .tag { background: var(--bg-section); color: var(--text-secondary); font-size: 0.72rem; padding: 0.2rem 0.6rem; border-radius: 999px; border: 1px solid var(--border-color); }
.related-tools { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 1rem; margin: 1.25rem 0; }
.related-tool-card { background: var(--bg-card); border: 1px solid var(--border-color); border-radius: var(--radius-lg); padding: 1rem; text-decoration: none; color: inherit; transition: border-color 0.15s, box-shadow 0.15s; }
.related-tool-card:hover { border-color: var(--accent-blue); box-shadow: var(--shadow-md); text-decoration: none; }
.related-tool-card .rt-icon { font-size: 1.5rem; }
.related-tool-card .rt-title { font-weight: 700; color: var(--text-primary); margin-top: 0.3rem; font-size: 0.92rem; }
.related-tool-card .rt-desc { font-size: 0.8rem; color: var(--text-muted); margin-top: 0.2rem; }

/* ===== 404 ===== */
.error-page { text-align: center; padding: 4rem 1rem; }
.error-page h1 { font-size: 3rem; color: var(--eng-blue); }
.error-page p { font-size: 1.1rem; color: var(--text-muted); margin-bottom: 1.5rem; }

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .main-nav { display: none; }
  .mobile-menu-btn { display: flex; }
  .calc-grid { grid-template-columns: 1fr; }
  h1 { font-size: 1.5rem; }
  h2 { font-size: 1.25rem; }
  .page-header { padding: 1.25rem; }
  .content-section { padding: 1.25rem; }
  .footer-col-group { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 480px) {
  .footer-col-group { grid-template-columns: 1fr; }
  .tool-grid { grid-template-columns: 1fr; }
  .blog-grid { grid-template-columns: 1fr; }
}

/* ===== Print ===== */
@media print {
  @page { margin: 1.5cm; }
  .site-header, .site-footer, .mobile-nav, .ad-block, .ad-slot, .calc-actions, .scenario-btns, .darkmode-toggle, .mobile-menu-btn, .main-nav { display: none !important; }
  body { font-size: 12px; color: #000; background: #fff; }
  .calc-panel, .content-section, .page-header { border: 1px solid #ccc; box-shadow: none; }
  details.seo-panel { display: none; }
  .container { max-width: 100%; }
  table, .data-table, tr, img { break-inside: avoid; }
  h1, h2, h3, h4 { break-after: avoid; }
}

/* ===== Cost Data & Sources page ===== */
.data-table { width: 100%; border-collapse: collapse; margin: 0.75rem 0 1rem; font-size: 0.9rem; }
.data-table th, .data-table td { border: 1px solid var(--border-color); padding: 0.55rem 0.7rem; text-align: left; vertical-align: top; }
.data-table th { background: var(--bg-section); color: var(--text-secondary); font-weight: 700; }
.data-table tbody tr:nth-child(even) { background: var(--bg-section); }
.content-section h3 { margin-top: 1.25rem; font-size: 1.02rem; color: var(--eng-blue); }
.steps { margin: 0.5rem 0 1rem; padding-left: 1.4rem; line-height: 1.6; }
.steps li { margin-bottom: 0.6rem; }
.source-list { margin: 0.5rem 0; padding-left: 1.2rem; line-height: 1.7; }
.source-info { font-size: 0.8rem; color: var(--text-muted); margin-top: 0.5rem; }
.disclaimer-box { border-left: 4px solid var(--accent-blue); background: var(--bg-section); }

/* ===== Calculator input validation ===== */
.calc-error { display: none; color: #b91c1c; font-size: 0.78rem; font-weight: 600; margin-top: 0.25rem; }
.input-group.input-invalid .calc-error { display: block; }
.input-group.input-invalid input { border-color: #dc2626; box-shadow: 0 0 0 3px rgba(220,38,38,0.12); }
@media (prefers-color-scheme: dark) {
  .calc-error { color: #fca5a5; }
  .input-group.input-invalid input { border-color: #f87171; }
}