:root {
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --bg-primary: #0a0f1d;
  --bg-secondary: #111827;
  --bg-card: rgba(26, 34, 53, 0.75);
  --bg-card-hover: rgba(35, 46, 72, 0.9);
  --border-color: rgba(255, 255, 255, 0.08);
  --border-glow: rgba(99, 102, 241, 0.3);
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent-color: #6366f1;
  --accent-hover: #4f46e5;
  --accent-gradient: linear-gradient(135deg, #6366f1 0%, #a855f7 50%, #ec4899 100%);
  --badge-bg: rgba(99, 102, 241, 0.15);
  --badge-text: #818cf8;
  --badge-border: rgba(99, 102, 241, 0.3);
  --shadow-sm: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.5), 0 8px 10px -6px rgba(0, 0, 0, 0.5);
  --radius-lg: 18px;
  --radius-md: 12px;
  --radius-sm: 8px;
  --transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}

[data-theme="light"] {
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --bg-card: rgba(255, 255, 255, 0.85);
  --bg-card-hover: #ffffff;
  --border-color: rgba(0, 0, 0, 0.08);
  --border-glow: rgba(99, 102, 241, 0.25);
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  --badge-bg: rgba(99, 102, 241, 0.08);
  --badge-text: #4f46e5;
  --badge-border: rgba(99, 102, 241, 0.2);
  --shadow-sm: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
  --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.06);
}

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

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

body {
  font-family: var(--font-family);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  position: relative;
  overflow-x: hidden;
  transition: background-color 0.3s ease, color 0.3s ease;
}

/* Background ambient glow */
body::before {
  content: "";
  position: fixed;
  top: -150px;
  left: 50%;
  transform: translateX(-50%);
  width: 700px;
  height: 500px;
  background: radial-gradient(circle, rgba(99, 102, 241, 0.15) 0%, rgba(168, 85, 247, 0.08) 50%, transparent 70%);
  pointer-events: none;
  z-index: 0;
}

/* Header & Nav */
header.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  background-color: rgba(10, 15, 29, 0.75);
  border-bottom: 1px solid var(--border-color);
  transition: var(--transition);
}

[data-theme="light"] header.site-header {
  background-color: rgba(255, 255, 255, 0.85);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 1rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--text-primary);
  font-weight: 700;
  font-size: 1.35rem;
  letter-spacing: -0.02em;
}

.brand-icon {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  background: var(--accent-gradient);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-weight: 800;
  font-size: 1.1rem;
  box-shadow: 0 4px 12px rgba(99, 102, 241, 0.4);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  list-style: none;
}

.nav-links a {
  text-decoration: none;
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.95rem;
  transition: var(--transition);
}

.nav-links a:hover {
  color: var(--text-primary);
}

.theme-toggle-btn {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 0.5rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  transition: var(--transition);
}

.theme-toggle-btn:hover {
  color: var(--text-primary);
  border-color: var(--border-glow);
}

/* Hero Section */
.hero-section {
  position: relative;
  max-width: 900px;
  margin: 0 auto;
  padding: 4.5rem 1.5rem 3rem 1.5rem;
  text-align: center;
  z-index: 1;
}

.hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.35rem 0.9rem;
  border-radius: 9999px;
  background: var(--badge-bg);
  color: var(--badge-text);
  border: 1px solid var(--badge-border);
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 1.5rem;
  letter-spacing: 0.02em;
}

.hero-title {
  font-size: clamp(2.3rem, 5vw, 3.6rem);
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.03em;
  margin-bottom: 1.25rem;
}

.gradient-text {
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-desc {
  font-size: 1.15rem;
  color: var(--text-secondary);
  max-width: 680px;
  margin: 0 auto 2.25rem auto;
  line-height: 1.7;
}

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

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  text-decoration: none;
  cursor: pointer;
  transition: var(--transition);
  border: none;
}

.btn-primary {
  background: var(--accent-gradient);
  color: #ffffff;
  box-shadow: 0 4px 15px rgba(99, 102, 241, 0.35);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(99, 102, 241, 0.45);
}

.btn-outline {
  background: transparent;
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

.btn-outline:hover {
  background: rgba(255, 255, 255, 0.05);
  border-color: var(--border-glow);
}

/* Category Filter Bar */
.filter-container {
  max-width: 1200px;
  margin: 1.5rem auto 2.5rem auto;
  padding: 0 1.5rem;
  display: flex;
  justify-content: center;
  gap: 0.5rem;
  flex-wrap: wrap;
  z-index: 1;
  position: relative;
}

.filter-btn {
  padding: 0.5rem 1.1rem;
  font-size: 0.9rem;
  font-weight: 500;
  border-radius: 9999px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  cursor: pointer;
  transition: var(--transition);
}

.filter-btn:hover {
  color: var(--text-primary);
  border-color: var(--border-glow);
}

.filter-btn.active {
  background: var(--accent-color);
  color: #ffffff;
  border-color: var(--accent-color);
  box-shadow: 0 4px 12px rgba(99, 102, 241, 0.3);
}

/* Main Content Sections */
.main-content {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem 4rem 1.5rem;
  position: relative;
  z-index: 1;
}

.section-block {
  margin-bottom: 4rem;
}

.section-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 1.75rem;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 0.75rem;
}

.section-title {
  font-size: 1.6rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  display: flex;
  align-items: center;
  gap: 0.65rem;
}

.section-count {
  font-size: 0.9rem;
  color: var(--text-muted);
  font-weight: 500;
}

/* Project Cards Grid */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 1.75rem;
}

.project-card {
  background: var(--bg-card);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: var(--transition);
  box-shadow: var(--shadow-sm);
  position: relative;
}

.project-card:hover {
  transform: translateY(-4px);
  background: var(--bg-card-hover);
  border-color: var(--border-glow);
  box-shadow: var(--shadow-lg);
}

.card-media {
  position: relative;
  width: 100%;
  height: 180px;
  overflow: hidden;
  background: #0d1322;
}

.card-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}

.project-card:hover .card-media img {
  transform: scale(1.05);
}

.card-icon-overlay {
  position: absolute;
  bottom: -20px;
  left: 20px;
  width: 54px;
  height: 54px;
  border-radius: var(--radius-md);
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.4);
  border: 2px solid var(--bg-secondary);
  overflow: hidden;
  background: var(--bg-secondary);
}

.card-icon-overlay img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.card-body {
  padding: 1.8rem 1.4rem 1.4rem 1.4rem;
  flex: 1;
  display: flex;
  flex-direction: column;
}

.card-title-group {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 0.5rem;
  margin-bottom: 0.5rem;
}

.card-title {
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--text-primary);
}

.status-badge {
  font-size: 0.72rem;
  font-weight: 600;
  padding: 0.2rem 0.55rem;
  border-radius: 6px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  white-space: nowrap;
}

.badge-green {
  background: rgba(16, 185, 129, 0.15);
  color: #34d399;
  border: 1px solid rgba(16, 185, 129, 0.3);
}

.badge-purple {
  background: rgba(168, 85, 247, 0.15);
  color: #c084fc;
  border: 1px solid rgba(168, 85, 247, 0.3);
}

.badge-amber {
  background: rgba(245, 158, 11, 0.15);
  color: #fbbf24;
  border: 1px solid rgba(245, 158, 11, 0.3);
}

.card-desc {
  font-size: 0.92rem;
  color: var(--text-secondary);
  margin-bottom: 1.25rem;
  flex: 1;
  line-height: 1.55;
}

.tags-list {
  display: flex;
  gap: 0.4rem;
  flex-wrap: wrap;
  margin-bottom: 1.25rem;
}

.tag-item {
  font-size: 0.75rem;
  padding: 0.15rem 0.5rem;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  color: var(--text-muted);
}

.card-actions {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 1rem;
  border-top: 1px solid var(--border-color);
  margin-top: auto;
}

.card-links {
  display: flex;
  gap: 0.6rem;
  align-items: center;
}

.link-btn {
  font-size: 0.85rem;
  font-weight: 600;
  text-decoration: none;
  color: var(--text-primary);
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.35rem 0.7rem;
  border-radius: var(--radius-sm);
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-color);
  transition: var(--transition);
}

.link-btn:hover {
  background: var(--accent-color);
  color: #ffffff;
  border-color: var(--accent-color);
}

.link-privacy {
  font-size: 0.8rem;
  color: var(--text-muted);
  text-decoration: none;
  transition: var(--transition);
}

.link-privacy:hover {
  color: var(--badge-text);
  text-decoration: underline;
}

/* Book Specific Card adjustments */
.book-card .card-media {
  height: 240px;
  background: #141b2d;
  display: flex;
  align-items: center;
  justify-content: center;
}

.book-card .card-media img {
  height: 90%;
  width: auto;
  border-radius: 6px;
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.4);
}

/* Privacy Hub Section */
.privacy-hub {
  background: var(--bg-card);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 2.5rem 2rem;
  margin-top: 2rem;
}

.privacy-hub-header {
  margin-bottom: 1.5rem;
}

.privacy-hub-header h2 {
  font-size: 1.4rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.privacy-hub-header p {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.privacy-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.25rem;
}

.privacy-item {
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1rem 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.privacy-item-title {
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--text-primary);
}

.privacy-item-links {
  display: flex;
  gap: 0.75rem;
}

.privacy-link {
  font-size: 0.85rem;
  color: var(--badge-text);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  transition: var(--transition);
}

.privacy-link:hover {
  text-decoration: underline;
  color: var(--accent-hover);
}

/* Footer */
footer.site-footer {
  border-top: 1px solid var(--border-color);
  background-color: var(--bg-secondary);
  padding: 3rem 1.5rem 2rem 1.5rem;
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.footer-container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.footer-top {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 1.5rem;
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border-color);
  font-size: 0.85rem;
  color: var(--text-muted);
}

.footer-links {
  display: flex;
  gap: 1.5rem;
  list-style: none;
}

.footer-links a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: var(--transition);
}

.footer-links a:hover {
  color: var(--text-primary);
}

/* Responsive adjustments */
@media (max-width: 768px) {
  .hero-section {
    padding: 3rem 1rem 2rem 1rem;
  }
  
  .nav-links {
    display: none;
  }
  
  .cards-grid {
    grid-template-columns: 1fr;
  }
  
  .footer-top, .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
  }
}