/* ==========================================================================
   TechSignal Hub - White Page Design System (Compliance & High Aesthetic)
   ========================================================================== */

/* --- CSS Variables & Design Tokens --- */
:root {
  --bg-main: #ffffff;
  --bg-surface: #ffffff;
  --bg-alt: #f8fafc;
  --bg-subtle: #f1f5f9;
  
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;

  --accent-primary: #2563eb;
  --accent-hover: #1d4ed8;
  --accent-light: #eff6ff;
  
  --border-light: #e2e8f0;
  --border-focus: #93c5fd;

  --shadow-sm: 0 1px 2px 0 rgba(15, 23, 42, 0.04);
  --shadow-md: 0 4px 6px -1px rgba(15, 23, 42, 0.06), 0 2px 4px -2px rgba(15, 23, 42, 0.04);
  --shadow-lg: 0 10px 15px -3px rgba(15, 23, 42, 0.08), 0 4px 6px -4px rgba(15, 23, 42, 0.04);
  --shadow-modal: 0 20px 25px -5px rgba(15, 23, 42, 0.15), 0 8px 10px -6px rgba(15, 23, 42, 0.1);

  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --radius-full: 9999px;

  --font-family: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

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

body {
  font-family: var(--font-family);
  background-color: var(--bg-main);
  color: var(--text-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* --- Typography --- */
h1, h2, h3, h4, h5, h6 {
  color: var(--text-primary);
  font-weight: 700;
  line-height: 1.25;
  letter-spacing: -0.02em;
}

p {
  color: var(--text-secondary);
}

a {
  color: inherit;
  text-decoration: none;
}

/* --- Container & Layout --- */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.75rem 1.5rem;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
  cursor: pointer;
  border: 1px solid transparent;
  text-align: center;
}

.btn-primary {
  background-color: var(--accent-primary);
  color: #ffffff;
  box-shadow: 0 2px 4px rgba(37, 99, 235, 0.2);
}

.btn-primary:hover {
  background-color: var(--accent-hover);
  transform: translateY(-1px);
  box-shadow: 0 4px 8px rgba(37, 99, 235, 0.3);
}

.btn-secondary {
  background-color: var(--bg-subtle);
  color: var(--text-primary);
  border-color: var(--border-light);
}

.btn-secondary:hover {
  background-color: var(--border-light);
}

.btn-outline {
  background-color: transparent;
  color: var(--accent-primary);
  border-color: var(--border-light);
}

.btn-outline:hover {
  background-color: var(--accent-light);
  border-color: var(--accent-primary);
}

/* --- Header & Navigation --- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-light);
  padding: 1rem 0;
}

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

.brand-logo {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 1.25rem;
  font-weight: 500;
  color: var(--text-primary);
}

.brand-logo .logo-icon {
  color: var(--accent-primary);
}

.brand-logo strong {
  color: var(--accent-primary);
  font-weight: 800;
}

.main-nav ul {
  display: flex;
  align-items: center;
  gap: 2rem;
  list-style: none;
}

.nav-link {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: color var(--transition-fast);
}

.nav-link:hover {
  color: var(--accent-primary);
}

/* --- Hero Section --- */
.hero-section {
  padding: 5rem 0 4rem 0;
  text-align: center;
  background: radial-gradient(circle at 50% 0%, rgba(219, 234, 254, 0.4) 0%, rgba(255, 255, 255, 0) 70%);
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 1rem;
  background-color: var(--accent-light);
  color: var(--accent-primary);
  font-size: 0.85rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  border: 1px solid rgba(147, 197, 253, 0.5);
  margin-bottom: 1.5rem;
}

.badge-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--accent-primary);
}

.hero-title {
  font-size: 3rem;
  font-weight: 800;
  max-width: 900px;
  margin: 0 auto 1.25rem auto;
  color: var(--text-primary);
}

.hero-description {
  font-size: 1.15rem;
  color: var(--text-secondary);
  max-width: 720px;
  margin: 0 auto 2rem auto;
}

.hero-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  margin-bottom: 3.5rem;
}

/* Metrics Grid */
.metrics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.5rem;
  margin-top: 2rem;
}

.metric-card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
  text-align: center;
}

.metric-value {
  font-size: 2rem;
  font-weight: 800;
  color: var(--accent-primary);
  margin-bottom: 0.25rem;
}

.metric-label {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-secondary);
}

/* --- Section Formatting --- */
.section {
  padding: 5rem 0;
}

.section-alt {
  background-color: var(--bg-alt);
  border-top: 1px solid var(--border-light);
  border-bottom: 1px solid var(--border-light);
}

.section-header {
  text-align: center;
  max-width: 650px;
  margin: 0 auto 3.5rem auto;
}

.section-subtitle {
  text-transform: uppercase;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--accent-primary);
  margin-bottom: 0.5rem;
  display: block;
}

.section-title {
  font-size: 2.2rem;
  margin-bottom: 1rem;
}

.section-description {
  font-size: 1.05rem;
  color: var(--text-secondary);
}

/* --- Cards Grid (Articles) --- */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: 2rem;
}

.card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 2rem;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-normal);
  display: flex;
  flex-direction: column;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: var(--border-focus);
}

.card-tag {
  align-self: flex-start;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 0.25rem 0.65rem;
  background-color: var(--bg-subtle);
  color: var(--accent-primary);
  border-radius: var(--radius-sm);
  margin-bottom: 1rem;
}

.card-title {
  font-size: 1.25rem;
  margin-bottom: 0.75rem;
  color: var(--text-primary);
}

.card-text {
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
  flex-grow: 1;
}

.card-footer {
  border-top: 1px solid var(--bg-subtle);
  padding-top: 1rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.read-time {
  font-size: 0.85rem;
  color: var(--text-muted);
  font-weight: 500;
}

/* --- Steps Grid (Tips) --- */
.steps-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.5rem;
}

.step-item {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  padding: 2rem 1.5rem;
  box-shadow: var(--shadow-sm);
  position: relative;
}

.step-number {
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--accent-light);
  line-height: 1;
  margin-bottom: 1rem;
}

.step-title {
  font-size: 1.1rem;
  margin-bottom: 0.5rem;
}

.step-text {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

/* --- FAQ Accordion --- */
.faq-accordion {
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.faq-item {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.5rem;
  box-shadow: var(--shadow-sm);
  transition: border-color var(--transition-fast);
}

.faq-item[open] {
  border-color: var(--accent-primary);
}

.faq-question {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-primary);
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.faq-question::-webkit-details-marker {
  display: none;
}

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

.faq-item[open] .faq-question::after {
  content: "−";
}

.faq-answer {
  margin-top: 1rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--bg-subtle);
  font-size: 0.95rem;
  color: var(--text-secondary);
}

/* --- Footer --- */
.site-footer {
  background-color: var(--bg-alt);
  border-top: 1px solid var(--border-light);
  padding: 4rem 0 2rem 0;
}

.footer-top {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 3rem;
  margin-bottom: 3rem;
}

.footer-tagline {
  margin-top: 1rem;
  font-size: 0.9rem;
  color: var(--text-secondary);
  max-width: 360px;
}

.footer-heading {
  font-size: 0.95rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-primary);
  margin-bottom: 1.25rem;
}

.footer-nav ul, .policy-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.footer-nav a {
  font-size: 0.9rem;
  color: var(--text-secondary);
  transition: color var(--transition-fast);
}

.footer-nav a:hover {
  color: var(--accent-primary);
}

.btn-policy {
  background: none;
  border: none;
  padding: 0;
  font-family: inherit;
  font-size: 0.9rem;
  color: var(--text-secondary);
  cursor: pointer;
  text-align: left;
  transition: color var(--transition-fast);
}

.btn-policy:hover {
  color: var(--accent-primary);
  text-decoration: underline;
}

.footer-divider {
  border: none;
  border-top: 1px solid var(--border-light);
  margin-bottom: 2rem;
}

.footer-bottom {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.25rem;
  text-align: center;
}

.copyright {
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* Meta / Facebook Disclaimer Box */
.fb-disclaimer-box {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-sm);
  padding: 1rem 1.5rem;
  max-width: 850px;
}

.fb-disclaimer-text {
  font-size: 0.78rem;
  color: var(--text-muted);
  line-height: 1.5;
}

/* --- Floating Box Modals (<dialog>) --- */
.floating-modal {
  margin: auto;
  border: none;
  border-radius: var(--radius-lg);
  padding: 0;
  background: transparent;
  max-width: 600px;
  width: 90%;
  box-shadow: var(--shadow-modal);
  opacity: 0;
  transform: scale(0.95);
  transition: opacity 0.25s ease, transform 0.25s ease;
}

.floating-modal[open] {
  opacity: 1;
  transform: scale(1);
}

.floating-modal::backdrop {
  background: rgba(15, 23, 42, 0.45);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  animation: fadeIn 0.25s ease;
}

.modal-content {
  background-color: var(--bg-surface);
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border-light);
}

.modal-header {
  padding: 1.25rem 1.75rem;
  background-color: var(--bg-alt);
  border-bottom: 1px solid var(--border-light);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.modal-header h3 {
  font-size: 1.2rem;
  color: var(--text-primary);
}

.modal-close {
  background: none;
  border: none;
  font-size: 1.5rem;
  color: var(--text-muted);
  cursor: pointer;
  line-height: 1;
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius-sm);
  transition: background-color var(--transition-fast);
}

.modal-close:hover {
  background-color: var(--border-light);
  color: var(--text-primary);
}

.modal-body {
  padding: 1.75rem;
  max-height: 65vh;
  overflow-y: auto;
  font-size: 0.95rem;
  color: var(--text-secondary);
}

.modal-body h4 {
  font-size: 1rem;
  margin: 1.25rem 0 0.5rem 0;
  color: var(--text-primary);
}

.modal-body p {
  margin-bottom: 0.85rem;
}

.contact-info {
  background-color: var(--bg-subtle);
  padding: 1rem;
  border-radius: var(--radius-sm);
  margin-bottom: 1.25rem;
  font-size: 0.9rem;
}

.modal-form {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-top: 1rem;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  text-align: left;
}

.form-group label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-primary);
}

.form-group input, .form-group textarea {
  padding: 0.65rem 0.85rem;
  border: 1px solid var(--border-light);
  border-radius: var(--radius-sm);
  font-family: inherit;
  font-size: 0.9rem;
  color: var(--text-primary);
  outline: none;
  transition: border-color var(--transition-fast);
}

.form-group input:focus, .form-group textarea:focus {
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

.modal-footer {
  padding: 1rem 1.75rem;
  background-color: var(--bg-alt);
  border-top: 1px solid var(--border-light);
  display: flex;
  justify-content: flex-end;
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

/* --- Responsive Adjustments --- */
@media (max-width: 900px) {
  .hero-title {
    font-size: 2.2rem;
  }

  .footer-top {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .main-nav {
    display: none; /* Can be expanded if hamburger is requested */
  }
}

@media (max-width: 600px) {
  .hero-title {
    font-size: 1.8rem;
  }

  .hero-actions {
    flex-direction: column;
    width: 100%;
  }

  .btn {
    width: 100%;
  }

  .cards-grid {
    grid-template-columns: 1fr;
  }
}