:root {
  --color-primary: #2b6cb0;
  --color-primary-light: #ebf4ff;
  --color-primary-dark: #1a4971;
  --color-accent: #5a67d8;
  --color-text: #2d3748;
  --color-text-light: #4a5568;
  --color-bg: #ffffff;
  --color-bg-warm: #f7fafc;
  --color-bg-section: #edf2f7;
  --color-border: #e2e8f0;
  --color-success: #38a169;
  --font-body: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  --font-heading: Georgia, 'Times New Roman', serif;
  --max-width: 1100px;
  --header-height: 72px;
}

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

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

body {
  font-family: var(--font-body);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

main {
  flex: 1;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Header & Navigation */
.site-header {
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-height);
}

.nav-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.site-logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--color-text);
}

.site-logo img {
  height: 48px;
  width: 48px;
  object-fit: contain;
  border-radius: 8px;
}

.site-name {
  font-family: var(--font-heading);
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--color-primary-dark);
}

.nav-menu {
  list-style: none;
  display: flex;
  gap: 0.25rem;
}

.nav-menu a {
  text-decoration: none;
  color: var(--color-text-light);
  padding: 0.5rem 1rem;
  border-radius: 6px;
  font-size: 0.95rem;
  font-weight: 500;
  transition: background 0.2s, color 0.2s;
}

.nav-menu a:hover,
.nav-menu a.active {
  background: var(--color-primary-light);
  color: var(--color-primary);
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
}

.hamburger,
.hamburger::before,
.hamburger::after {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-text);
  transition: transform 0.3s;
}

.hamburger {
  position: relative;
}

.hamburger::before,
.hamburger::after {
  content: '';
  position: absolute;
}

.hamburger::before { top: -7px; }
.hamburger::after { top: 7px; }

/* Hero */
.hero {
  background: linear-gradient(135deg, var(--color-primary-light) 0%, var(--color-bg-section) 50%, #f0e6ff 100%);
  padding: 5rem 1.5rem;
  text-align: center;
}

.hero-content {
  max-width: 700px;
  margin: 0 auto;
}

.hero-logo {
  width: 120px;
  height: 120px;
  object-fit: contain;
  border-radius: 24px;
  margin-bottom: 1.5rem;
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.1);
}

.hero h1 {
  font-family: var(--font-heading);
  font-size: 2.75rem;
  color: var(--color-primary-dark);
  margin-bottom: 1rem;
  letter-spacing: -0.5px;
}

.hero-tagline {
  font-size: 1.25rem;
  color: var(--color-text-light);
  line-height: 1.6;
}

/* Intro */
.intro {
  padding: 3rem 0;
}

.intro p {
  font-size: 1.1rem;
  max-width: 800px;
  margin: 0 auto;
  text-align: center;
  color: var(--color-text-light);
}

/* Card Grid */
.sections-overview {
  padding: 2rem 0 5rem;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.5rem;
}

.card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 12px;
  padding: 2rem;
  text-decoration: none;
  color: var(--color-text);
  transition: transform 0.2s, box-shadow 0.2s;
}

.card:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.08);
}

.card-icon {
  font-size: 2rem;
  margin-bottom: 1rem;
}

.card h2 {
  font-family: var(--font-heading);
  font-size: 1.4rem;
  color: var(--color-primary-dark);
  margin-bottom: 0.75rem;
}

.card p {
  color: var(--color-text-light);
  font-size: 0.95rem;
  line-height: 1.6;
}

/* Page Header */
.page-header {
  background: var(--color-bg-section);
  padding: 3rem 0;
  border-bottom: 1px solid var(--color-border);
}

.page-header h1 {
  font-family: var(--font-heading);
  font-size: 2.25rem;
  color: var(--color-primary-dark);
  margin-bottom: 0.5rem;
}

.page-description {
  font-size: 1.1rem;
  color: var(--color-text-light);
  max-width: 700px;
}

/* Page Content */
.page-content {
  padding: 3rem 0 5rem;
}

.page-content h2 {
  font-family: var(--font-heading);
  font-size: 1.6rem;
  color: var(--color-primary-dark);
  margin: 2.5rem 0 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--color-primary-light);
}

.page-content h3 {
  font-size: 1.2rem;
  color: var(--color-text);
  margin: 2rem 0 0.75rem;
}

.page-content p {
  margin-bottom: 1rem;
}

.page-content ul, .page-content ol {
  margin: 0.5rem 0 1.5rem 1.5rem;
}

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

.page-content a {
  color: var(--color-primary);
  text-decoration: underline;
  text-decoration-color: var(--color-primary-light);
  text-underline-offset: 2px;
}

.page-content a:hover {
  text-decoration-color: var(--color-primary);
}

/* Article List */
.article-list {
  margin-top: 2rem;
}

.article-card {
  padding: 1.5rem;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  margin-bottom: 1rem;
  transition: background 0.2s;
}

.article-card:hover {
  background: var(--color-bg-warm);
}

.article-card h2 {
  font-size: 1.25rem;
  margin: 0 0 0.5rem;
  border: none;
  padding: 0;
}

.article-card h2 a {
  color: var(--color-primary-dark);
  text-decoration: none;
}

.article-card h2 a:hover {
  color: var(--color-primary);
}

.article-card p {
  color: var(--color-text-light);
  font-size: 0.95rem;
  margin: 0;
}

/* Section Nav */
.section-nav {
  margin-top: 3rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--color-border);
}

.section-nav a {
  color: var(--color-primary);
  text-decoration: none;
  font-weight: 500;
}

.section-nav a:hover {
  text-decoration: underline;
}

/* Info Box */
.info-box {
  background: var(--color-primary-light);
  border-left: 4px solid var(--color-primary);
  padding: 1.25rem 1.5rem;
  border-radius: 0 8px 8px 0;
  margin: 1.5rem 0;
}

.info-box p {
  margin: 0;
  color: var(--color-primary-dark);
}

/* Tool Card */
.tool-card {
  background: var(--color-bg);
  border: 2px solid var(--color-primary-light);
  border-radius: 12px;
  padding: 2rem;
  margin: 1.5rem 0;
}

.tool-card h3 {
  color: var(--color-primary-dark);
  margin-top: 0;
}

.tool-card .btn {
  display: inline-block;
  background: var(--color-primary);
  color: white;
  padding: 0.75rem 1.5rem;
  border-radius: 8px;
  text-decoration: none;
  font-weight: 600;
  margin-top: 1rem;
  transition: background 0.2s;
}

.tool-card .btn:hover {
  background: var(--color-primary-dark);
}

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

.footer-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 2rem;
}

.footer-info p {
  font-size: 0.875rem;
  color: var(--color-text-light);
}

.disclaimer {
  margin-top: 0.5rem;
  font-size: 0.8rem !important;
  font-style: italic;
}

.footer-links {
  display: flex;
  gap: 1.5rem;
}

.footer-links a {
  color: var(--color-primary);
  text-decoration: none;
  font-size: 0.875rem;
  font-weight: 500;
}

.footer-links a:hover {
  text-decoration: underline;
}

/* Responsive */
@media (max-width: 768px) {
  .nav-toggle {
    display: block;
  }

  .nav-menu {
    display: none;
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    flex-direction: column;
    padding: 1rem;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
  }

  .nav-menu.open {
    display: flex;
  }

  .hero h1 {
    font-size: 2rem;
  }

  .hero-tagline {
    font-size: 1.1rem;
  }

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

  .footer-container {
    flex-direction: column;
  }

  .page-header h1 {
    font-size: 1.75rem;
  }
}