/* ==========================================================================
   SLAB COST CALCULATOR - MAIN THEME STYLESHEET
   Design Language: Modern Construction Engineering & Professional Estimating
   ========================================================================== */

:root {
  /* Color Palette */
  --primary-50: #eff6ff;
  --primary-100: #dbeafe;
  --primary-200: #bfdbfe;
  --primary-500: #3b82f6;
  --primary-600: #2563eb;
  --primary-700: #1d4ed8;
  --primary-800: #1e40af;
  --primary-900: #1e3a8a;

  --accent-amber: #f59e0b;
  --accent-amber-dark: #d97706;
  --accent-emerald: #10b981;
  --accent-cyan: #06b6d4;

  --slate-50: #f8fafc;
  --slate-100: #f1f5f9;
  --slate-200: #e2e8f0;
  --slate-300: #cbd5e1;
  --slate-400: #94a3b8;
  --slate-500: #64748b;
  --slate-600: #475569;
  --slate-700: #334155;
  --slate-800: #1e293b;
  --slate-900: #0f172a;
  --slate-950: #020617;

  /* Spacing & Radii */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);

  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
}

/* Reset & Box Sizing */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-family: var(--font-sans);
  line-height: 1.6;
  color: var(--slate-800);
  background-color: var(--slate-50);
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a {
  color: var(--primary-600);
  text-decoration: none;
  transition: color 0.15s ease-in-out;
}

a:hover {
  color: var(--primary-800);
  text-decoration: underline;
}

img, svg {
  max-width: 100%;
  height: auto;
  vertical-align: middle;
}

/* Container */
.container {
  width: 100%;
  max-width: 1240px;
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.25rem;
  padding-right: 1.25rem;
}

.container-narrow {
  max-width: 900px;
}

/* ==========================================================================
   HEADER & NAVIGATION
   ========================================================================== */

.site-header {
  background-color: #ffffff;
  border-bottom: 1px solid var(--slate-200);
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: var(--shadow-sm);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.site-branding a {
  display: flex;
  align-items: center;
  text-decoration: none;
}

.site-logo {
  height: 44px;
  width: auto;
}

.primary-nav {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.nav-links {
  display: flex;
  list-style: none;
  align-items: center;
  gap: 1.25rem;
}

.nav-item {
  position: relative;
}

.nav-link {
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--slate-700);
  padding: 0.5rem 0.75rem;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  gap: 0.25rem;
  transition: all 0.15s ease;
}

.nav-link:hover, .nav-item.active .nav-link {
  color: var(--primary-600);
  background-color: var(--primary-50);
  text-decoration: none;
}

/* Dropdown */
.dropdown-menu {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 260px;
  background-color: #ffffff;
  border: 1px solid var(--slate-200);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-xl);
  padding: 0.5rem;
  list-style: none;
  z-index: 1010;
}

.nav-item:hover .dropdown-menu,
.nav-item:focus-within .dropdown-menu {
  display: block;
}

.dropdown-item a {
  display: block;
  padding: 0.5rem 0.75rem;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--slate-700);
  border-radius: var(--radius-sm);
  transition: all 0.15s ease;
}

.dropdown-item a:hover {
  background-color: var(--primary-50);
  color: var(--primary-600);
  text-decoration: none;
}

.header-cta-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background-color: var(--primary-600);
  color: #ffffff !important;
  font-size: 0.875rem;
  font-weight: 700;
  padding: 0.55rem 1.1rem;
  border-radius: var(--radius-md);
  transition: background-color 0.15s ease, transform 0.1s ease;
  text-decoration: none !important;
}

.header-cta-btn:hover {
  background-color: var(--primary-700);
  transform: translateY(-1px);
}

.mobile-menu-toggle {
  display: none;
  background: none;
  border: 1px solid var(--slate-300);
  padding: 0.5rem;
  border-radius: var(--radius-sm);
  color: var(--slate-700);
  cursor: pointer;
}

/* ==========================================================================
   BREADCRUMBS & TRUST BADGES
   ========================================================================== */

.breadcrumb-nav {
  padding: 0.75rem 0;
  background-color: var(--slate-100);
  border-bottom: 1px solid var(--slate-200);
  font-size: 0.8125rem;
}

.breadcrumb-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  list-style: none;
  gap: 0.5rem;
  color: var(--slate-500);
}

.breadcrumb-item a {
  color: var(--slate-600);
  font-weight: 500;
}

.breadcrumb-item a:hover {
  color: var(--primary-600);
}

.breadcrumb-separator {
  color: var(--slate-400);
}

.breadcrumb-current {
  color: var(--slate-800);
  font-weight: 600;
}

/* E-E-A-T Trust Bar */
.trust-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 1rem;
  padding: 0.65rem 1rem;
  background-color: #ffffff;
  border: 1px solid var(--slate-200);
  border-radius: var(--radius-md);
  margin: 1.25rem 0;
  font-size: 0.8125rem;
  color: var(--slate-600);
}

.trust-item {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.trust-item strong {
  color: var(--slate-800);
}

.trust-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  background-color: #ecfdf5;
  color: #065f46;
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius-full);
  font-weight: 600;
  font-size: 0.75rem;
}

/* ==========================================================================
   HERO & INTRO SECTIONS
   ========================================================================== */

.hero-section {
  background: linear-gradient(180deg, #ffffff 0%, var(--slate-50) 100%);
  padding: 2.5rem 0 1.5rem 0;
  border-bottom: 1px solid var(--slate-200);
}

.hero-title {
  font-size: 2.5rem;
  font-weight: 800;
  line-height: 1.15;
  color: var(--slate-900);
  letter-spacing: -0.025em;
  margin-bottom: 0.75rem;
}

.hero-subtitle {
  font-size: 1.125rem;
  line-height: 1.6;
  color: var(--slate-600);
  max-width: 840px;
}

.hero-key-takeaways {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
  margin-top: 1.5rem;
}

.takeaway-card {
  background: #ffffff;
  border: 1px solid var(--slate-200);
  border-left: 4px solid var(--primary-600);
  border-radius: var(--radius-md);
  padding: 0.875rem 1rem;
}

.takeaway-label {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--slate-500);
  margin-bottom: 0.25rem;
}

.takeaway-value {
  font-size: 1rem;
  font-weight: 700;
  color: var(--slate-900);
}

/* ==========================================================================
   CONTENT LAYOUT & TYPOGRAPHY
   ========================================================================== */

.site-main {
  flex: 1 0 auto;
  padding: 2.5rem 0;
}

.content-grid {
  display: grid;
  grid-template-columns: 1fr 340px;
  gap: 2.5rem;
}

.content-full {
  display: block;
}

.article-content {
  font-size: 1.0625rem;
  line-height: 1.75;
  color: var(--slate-800);
}

.article-content h2 {
  font-size: 1.875rem;
  font-weight: 800;
  line-height: 1.25;
  color: var(--slate-900);
  letter-spacing: -0.02em;
  margin-top: 2.5rem;
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--slate-200);
}

.article-content h3 {
  font-size: 1.375rem;
  font-weight: 700;
  line-height: 1.35;
  color: var(--slate-900);
  margin-top: 2rem;
  margin-bottom: 0.75rem;
}

.article-content h4 {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--slate-800);
  margin-top: 1.5rem;
  margin-bottom: 0.5rem;
}

.article-content p {
  margin-bottom: 1.25rem;
}

.article-content ul, .article-content ol {
  margin-bottom: 1.5rem;
  padding-left: 1.5rem;
}

.article-content li {
  margin-bottom: 0.5rem;
}

/* Technical Definition Box */
.definition-card {
  background-color: var(--primary-50);
  border: 1px solid var(--primary-200);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.5rem;
  margin: 1.5rem 0;
}

.definition-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--primary-900);
  margin-bottom: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.definition-card p {
  margin-bottom: 0;
  font-size: 0.9375rem;
  color: var(--slate-700);
}

/* Formula Box */
.formula-box {
  background-color: var(--slate-900);
  color: #ffffff;
  border-radius: var(--radius-md);
  padding: 1.25rem 1.5rem;
  margin: 1.5rem 0;
  font-family: var(--font-mono);
  overflow-x: auto;
}

.formula-label {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent-amber);
  margin-bottom: 0.5rem;
  font-family: var(--font-sans);
}

.formula-math {
  font-size: 1.125rem;
  font-weight: 700;
  color: #38bdf8;
  margin-bottom: 0.5rem;
}

.formula-explanation {
  font-size: 0.875rem;
  color: var(--slate-300);
  font-family: var(--font-sans);
}

/* Engineered Data Tables */
.table-responsive {
  width: 100%;
  overflow-x: auto;
  margin: 1.75rem 0;
  border: 1px solid var(--slate-200);
  border-radius: var(--radius-md);
  background: #ffffff;
  box-shadow: var(--shadow-sm);
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9375rem;
  text-align: left;
}

.data-table th {
  background-color: var(--slate-800);
  color: #ffffff;
  font-weight: 700;
  padding: 0.85rem 1rem;
  font-size: 0.8125rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  border-right: 1px solid var(--slate-700);
}

.data-table th:last-child {
  border-right: none;
}

.data-table td {
  padding: 0.85rem 1rem;
  border-bottom: 1px solid var(--slate-200);
  border-right: 1px solid var(--slate-100);
  color: var(--slate-700);
}

.data-table td:last-child {
  border-right: none;
}

.data-table tbody tr:nth-child(even) {
  background-color: var(--slate-50);
}

.data-table tbody tr:hover {
  background-color: var(--primary-50);
}

.table-caption {
  font-size: 0.8125rem;
  color: var(--slate-500);
  padding: 0.5rem 1rem;
  background-color: var(--slate-100);
  border-top: 1px solid var(--slate-200);
  font-style: italic;
}

/* Callout Alert Boxes */
.callout {
  padding: 1.25rem 1.5rem;
  border-radius: var(--radius-md);
  margin: 1.5rem 0;
  border-left: 4px solid;
}

.callout-info {
  background-color: #eff6ff;
  border-color: #3b82f6;
  color: #1e3a8a;
}

.callout-warning {
  background-color: #fffbeb;
  border-color: #f59e0b;
  color: #92400e;
}

.callout-tip {
  background-color: #ecfdf5;
  border-color: #10b981;
  color: #065f46;
}

.callout-title {
  font-weight: 700;
  font-size: 1rem;
  margin-bottom: 0.35rem;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

/* ==========================================================================
   SIDEBAR & SUPPORTING CALCULATOR WIDGETS
   ========================================================================== */

.sidebar-widget {
  background: #ffffff;
  border: 1px solid var(--slate-200);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  margin-bottom: 2rem;
  box-shadow: var(--shadow-sm);
}

.widget-title {
  font-size: 1.125rem;
  font-weight: 800;
  color: var(--slate-900);
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--primary-600);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.calculator-nav-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.calculator-nav-item a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.6rem 0.85rem;
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--slate-700);
  background-color: var(--slate-50);
  border: 1px solid var(--slate-200);
  transition: all 0.15s ease;
}

.calculator-nav-item a:hover {
  background-color: var(--primary-50);
  border-color: var(--primary-200);
  color: var(--primary-600);
  text-decoration: none;
}

.calculator-nav-badge {
  font-size: 0.6875rem;
  font-weight: 700;
  padding: 0.15rem 0.45rem;
  border-radius: var(--radius-full);
  background-color: var(--primary-100);
  color: var(--primary-800);
}

/* FAQ Accordion */
.faq-section {
  margin: 3rem 0;
}

.faq-item {
  background: #ffffff;
  border: 1px solid var(--slate-200);
  border-radius: var(--radius-md);
  margin-bottom: 0.75rem;
  overflow: hidden;
}

.faq-question {
  width: 100%;
  text-align: left;
  background: none;
  border: none;
  padding: 1.25rem 1.5rem;
  font-size: 1.0625rem;
  font-weight: 700;
  color: var(--slate-900);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  transition: background-color 0.15s ease;
}

.faq-question:hover {
  background-color: var(--slate-50);
}

.faq-question::after {
  content: "+";
  font-size: 1.5rem;
  font-weight: 400;
  color: var(--primary-600);
  transition: transform 0.2s ease;
}

.faq-item.active .faq-question::after {
  content: "−";
}

.faq-answer {
  display: none;
  padding: 0 1.5rem 1.25rem 1.5rem;
  color: var(--slate-700);
  font-size: 0.9375rem;
  line-height: 1.7;
}

.faq-item.active .faq-answer {
  display: block;
}

/* Author Box */
.author-box {
  display: flex;
  align-items: flex-start;
  gap: 1.25rem;
  background: #ffffff;
  border: 1px solid var(--slate-200);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  margin: 2.5rem 0;
}

.author-avatar {
  width: 72px;
  height: 72px;
  border-radius: var(--radius-full);
  background-color: var(--slate-200);
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  color: var(--slate-600);
  font-size: 1.5rem;
}

.author-meta h4 {
  font-size: 1.125rem;
  font-weight: 800;
  color: var(--slate-900);
  margin-bottom: 0.25rem;
}

.author-role {
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--primary-600);
  margin-bottom: 0.5rem;
}

.author-bio {
  font-size: 0.875rem;
  color: var(--slate-600);
  line-height: 1.6;
}

/* ==========================================================================
   FOOTER
   ========================================================================== */

.site-footer {
  background-color: var(--slate-900);
  color: var(--slate-300);
  padding: 4rem 0 2rem 0;
  margin-top: auto;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr repeat(3, 1fr);
  gap: 3rem;
  margin-bottom: 3rem;
}

.footer-branding-text {
  font-size: 0.875rem;
  color: var(--slate-400);
  margin-top: 1rem;
  line-height: 1.6;
  max-width: 320px;
}

.footer-col h4 {
  font-size: 0.875rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: #ffffff;
  margin-bottom: 1.25rem;
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
}

.footer-links a {
  color: var(--slate-400);
  font-size: 0.875rem;
  transition: color 0.15s ease;
}

.footer-links a:hover {
  color: #ffffff;
  text-decoration: none;
}

.footer-disclaimer-card {
  background-color: var(--slate-950);
  border: 1px solid var(--slate-800);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  margin-bottom: 2rem;
  font-size: 0.8125rem;
  color: var(--slate-400);
  line-height: 1.6;
}

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-top: 1px solid var(--slate-800);
  padding-top: 2rem;
  font-size: 0.8125rem;
  color: var(--slate-500);
}

/* ==========================================================================
   RESPONSIVE DESIGN
   ========================================================================== */

@media (max-width: 1024px) {
  .content-grid {
    grid-template-columns: 1fr;
  }
  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .hero-title {
    font-size: 2rem;
  }
  .primary-nav .nav-links {
    display: none;
  }
  .mobile-menu-toggle {
    display: block;
  }
  .footer-grid {
    grid-template-columns: 1fr;
    gap: 2rem;
  }
  .footer-bottom {
    flex-direction: column;
    gap: 1rem;
    text-align: center;
  }
}