:root {
  --bg-color: #0A1628;
  --card-bg: #111827;
  --primary-color: #3B82F6;
  --accent-color: #06B6D4;
  --text-primary: #E2E8F0;
  --text-secondary: #94A3B8;
  --border-color: rgba(59, 130, 246, 0.2);
  --header-bg: rgba(10, 22, 40, 0.85);
  --font-heading: 'Space Grotesk', sans-serif;
  --font-body: 'Inter', sans-serif;
}

body.light-mode {
  --bg-color: #F8FAFC;
  --card-bg: #FFFFFF;
  --primary-color: #2563EB;
  --accent-color: #0891B2;
  --text-primary: #0F172A;
  --text-secondary: #475569;
  --border-color: rgba(37, 99, 235, 0.2);
  --header-bg: rgba(248, 250, 252, 0.85);
}

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

body {
  background-color: var(--bg-color);
  color: var(--text-primary);
  font-family: var(--font-body);
  line-height: 1.6;
  overflow-x: hidden;
  transition: background-color 0.3s, color 0.3s;
}

h1, h2, h3, h4, h5, h6 { font-family: var(--font-heading); font-weight: 700; }
a { color: inherit; text-decoration: none; }

header {
  position: sticky; top: 0; z-index: 1000;
  background: var(--header-bg);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  box-shadow: 0 4px 30px rgba(59, 130, 246, 0.1);
  padding: 1rem 2rem;
  display: flex; justify-content: space-between; align-items: center;
}

.logo { font-family: var(--font-heading); font-size: 1.8rem; font-weight: 700; display: flex; align-items: center; gap: 10px; }
.logo i { color: var(--primary-color); }
.logo span { color: var(--accent-color); }

nav ul { display: flex; gap: 1.5rem; list-style: none; }
nav a { font-weight: 500; font-size: 0.95rem; transition: color 0.2s; }
nav a:hover { color: var(--accent-color); }

.mode-toggle { background: transparent; border: 1px solid var(--border-color); color: var(--text-primary); padding: 0.5rem 1rem; border-radius: 8px; cursor: pointer; transition: 0.3s; }
.mode-toggle:hover { background: var(--primary-color); color: #fff; }

.hero { padding: 4rem 2rem; text-align: center; background: linear-gradient(135deg, rgba(10,22,40,1) 0%, rgba(59,130,246,0.15) 100%); border-bottom: 1px solid var(--border-color); }
.hero h1 { font-size: 3rem; margin-bottom: 1rem; text-shadow: 0 0 20px rgba(6, 182, 212, 0.5); }
.hero p { font-size: 1.1rem; color: var(--text-secondary); max-width: 600px; margin: 0 auto; }

.container { max-width: 1200px; margin: 0 auto; padding: 2rem; }

/* Grid Layouts */
.featured-grid { display: grid; grid-template-columns: 2fr 1fr; gap: 2rem; margin-bottom: 4rem; }
.articles-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 2rem; }

.card {
  background: var(--card-bg); border: 1px solid var(--border-color); border-radius: 12px; overflow: hidden;
  transition: transform 0.3s, box-shadow 0.3s; display: flex; flex-direction: column; cursor: pointer;
}
.card:hover { transform: translateY(-5px); box-shadow: 0 0 20px rgba(59, 130, 246, 0.3); }

.card-img { width: 100%; height: 200px; object-fit: cover; border-bottom: 1px solid var(--border-color); }
.card-content { padding: 1.5rem; display: flex; flex-direction: column; flex-grow: 1; }
.card-category { font-size: 0.8rem; text-transform: uppercase; color: var(--accent-color); font-weight: 700; margin-bottom: 0.5rem; letter-spacing: 1px; }
.card-title { font-size: 1.25rem; margin-bottom: 0.5rem; line-height: 1.3; }
.card-summary { font-size: 0.95rem; color: var(--text-secondary); margin-bottom: 1.5rem; flex-grow: 1; }

.card-meta { display: flex; align-items: center; justify-content: space-between; font-size: 0.85rem; color: var(--text-secondary); }
.author-info { display: flex; align-items: center; gap: 10px; }
.author-avatar { width: 30px; height: 30px; border-radius: 50%; object-fit: cover; }

/* Article specific */
.article-header { text-align: center; margin-bottom: 3rem; }
.article-header h1 { font-size: 2.5rem; margin: 1rem 0; }
.article-hero-img { width: 100%; max-height: 500px; object-fit: cover; border-radius: 12px; margin-bottom: 3rem; border: 1px solid var(--border-color); }

.article-rich-body { max-width: 800px; margin: 0 auto; font-size: 1.1rem; line-height: 1.8; }
.article-rich-body h2 { margin: 2rem 0 1rem; color: var(--accent-color); }
.article-rich-body p { margin-bottom: 1.5rem; }
.article-intro-box { background: rgba(59, 130, 246, 0.05); padding: 1.5rem; border-left: 4px solid var(--primary-color); margin-bottom: 2rem; border-radius: 0 8px 8px 0; }
.lead-paragraph { font-size: 1.2rem; color: var(--text-primary); }

.key-takeaways-card { background: var(--card-bg); border: 1px solid var(--border-color); border-radius: 12px; padding: 1.5rem; margin: 2rem 0; box-shadow: 0 10px 30px rgba(0,0,0,0.2); }
.key-takeaways-card h3 { color: var(--accent-color); margin-bottom: 1rem; display: flex; align-items: center; gap: 10px; }
.key-takeaways-card ul { list-style: none; padding-left: 0; }
.key-takeaways-card li { margin-bottom: 0.5rem; padding-left: 1.5rem; position: relative; }
.key-takeaways-card li::before { content: '→'; position: absolute; left: 0; color: var(--primary-color); font-weight: bold; }

.article-quote { font-family: var(--font-heading); font-size: 1.4rem; font-style: italic; border-left: 4px solid var(--accent-color); padding: 1rem 2rem; margin: 2rem 0; background: linear-gradient(90deg, rgba(6,182,212,0.1) 0%, transparent 100%); }
.article-quote cite { display: block; font-size: 1rem; margin-top: 1rem; color: var(--text-secondary); font-style: normal; font-weight: bold; }

.pro-tip-box { background: linear-gradient(135deg, rgba(59, 130, 246, 0.1), rgba(6, 182, 212, 0.1)); border: 1px solid var(--accent-color); border-radius: 8px; padding: 1.5rem; margin: 2rem 0; }
.pro-tip-box h4 { color: var(--accent-color); margin-bottom: 0.5rem; display: flex; align-items: center; gap: 10px; }

/* Ads placeholder */
.taboola-placeholder { background: rgba(0,0,0,0.2); border: 1px dashed var(--text-secondary); padding: 2rem; text-align: center; color: var(--text-secondary); margin: 3rem 0; border-radius: 8px; }

footer { background: var(--card-bg); border-top: 1px solid var(--border-color); padding: 3rem 2rem; text-align: center; color: var(--text-secondary); margin-top: 4rem; }
.footer-links { display: flex; justify-content: center; gap: 2rem; margin-top: 1.5rem; }
.footer-links a:hover { color: var(--accent-color); }

@media (max-width: 768px) {
  .featured-grid { grid-template-columns: 1fr; }
  nav { display: none; } /* Add mobile menu logic if needed */
  .hero h1 { font-size: 2rem; }
}