/* Design Tokens */
:root {
  /* Color Palette (Sleek Dark Theme) */
  --bg-main: #0B0F19;
  --bg-card: rgba(17, 24, 39, 0.7);
  --bg-card-hover: rgba(26, 36, 57, 0.85);
  --border-color: rgba(255, 255, 255, 0.08);
  --border-focus: rgba(99, 102, 241, 0.4);
  
  --primary: #4F46E5;      /* Indigo */
  --primary-glow: rgba(79, 70, 229, 0.15);
  --accent: #06B6D4;       /* Cyan */
  --accent-glow: rgba(6, 182, 212, 0.15);
  
  --text-main: #F3F4F6;
  --text-muted: #9CA3AF;
  --text-inverse: #ffffff;
  
  --error: #EF4444;
  --success: #10B981;
  
  /* Fonts */
  --font-title: 'Outfit', sans-serif;
  --font-body: 'Inter', sans-serif;
  
  /* Transitions */
  --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Reset & Global */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  background-color: var(--bg-main);
  color: var(--text-main);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  position: relative;
}

/* Background Glow Effects */
.bg-glow {
  position: absolute;
  width: 40vw;
  height: 40vw;
  border-radius: 50%;
  filter: blur(120px);
  z-index: -1;
  pointer-events: none;
  opacity: 0.4;
}

.bg-glow-1 {
  background: radial-gradient(circle, var(--primary) 0%, transparent 70%);
  top: -10%;
  right: -5%;
}

.bg-glow-2 {
  background: radial-gradient(circle, var(--accent) 0%, transparent 70%);
  bottom: 10%;
  left: -10%;
}

/* Scrollbar Styling */
::-webkit-scrollbar {
  width: 10px;
}

::-webkit-scrollbar-track {
  background: var(--bg-main);
}

::-webkit-scrollbar-thumb {
  background: rgba(255, 255, 255, 0.1);
  border-radius: 5px;
  border: 2px solid var(--bg-main);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--primary);
}

/* Navigation & Header */
.app-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(11, 15, 25, 0.8);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-color);
  transition: var(--transition-normal);
}

.header-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 1rem 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo-link {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--text-main);
  font-family: var(--font-title);
  font-weight: 700;
  font-size: 1.25rem;
  letter-spacing: -0.02em;
}

.logo-icon {
  color: var(--primary);
  transition: var(--transition-fast);
}

.logo-link:hover .logo-icon {
  transform: scale(1.08) rotate(-5deg);
  color: var(--accent);
}

.mobile-nav-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--text-main);
  cursor: pointer;
  padding: 0.5rem;
}

.app-nav {
  display: flex;
  align-items: center;
  gap: 2rem;
}

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

.nav-link {
  text-decoration: none;
  color: var(--text-muted);
  font-weight: 500;
  font-size: 0.95rem;
  padding: 0.5rem 0.75rem;
  border-radius: 6px;
  transition: var(--transition-fast);
  position: relative;
}

.nav-link:hover {
  color: var(--text-main);
}

.nav-link.active {
  color: var(--accent);
  background: rgba(6, 182, 212, 0.08);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-title);
  font-weight: 600;
  font-size: 0.95rem;
  padding: 0.6rem 1.25rem;
  border-radius: 8px;
  border: 1px solid transparent;
  cursor: pointer;
  text-decoration: none;
  transition: var(--transition-fast);
}

.btn-primary {
  background: var(--primary);
  color: var(--text-inverse);
  box-shadow: 0 4px 14px var(--primary-glow);
}

.btn-primary:hover {
  background: #4338CA;
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(79, 70, 229, 0.3);
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-main);
  border-color: var(--border-color);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.1);
  transform: translateY(-2px);
}

.btn-accent {
  background: var(--accent);
  color: var(--bg-main);
  box-shadow: 0 4px 14px var(--accent-glow);
}

.btn-accent:hover {
  background: #0891B2;
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(6, 182, 212, 0.3);
}

.btn-lg {
  padding: 0.8rem 1.75rem;
  font-size: 1.05rem;
}

/* Main Layout & Containers */
.app-content {
  flex: 1;
  padding: 3rem 2rem;
}

.content-container {
  max-width: 900px;
  margin: 0 auto;
}

.view-section {
  display: none;
  animation: fadeIn 0.4s ease-out forwards;
}

.view-section.active {
  display: block;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(15px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Loading & Spinner */
.loader-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 300px;
  gap: 1.5rem;
}

.spinner {
  width: 48px;
  height: 48px;
  border: 4px solid var(--border-color);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

.loader-text {
  color: var(--text-muted);
  font-size: 0.95rem;
  font-weight: 500;
}

/* Error boundary */
.error-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  padding: 3rem 2rem;
  border-radius: 12px;
  background: rgba(239, 68, 68, 0.05);
  border: 1px solid rgba(239, 68, 68, 0.15);
  gap: 1rem;
}

.error-title {
  font-family: var(--font-title);
  color: var(--text-main);
}

.error-msg {
  color: var(--text-muted);
  max-width: 500px;
  margin-bottom: 1rem;
}

.hidden {
  display: none !important;
}

/* Hero Section */
.hero {
  text-align: center;
  padding: 4rem 1rem 5rem;
  position: relative;
}

.badge {
  display: inline-block;
  padding: 0.35rem 0.85rem;
  background: rgba(79, 70, 229, 0.1);
  color: #818CF8;
  border: 1px solid rgba(79, 70, 229, 0.2);
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 1.5rem;
}

.hero-title {
  font-family: var(--font-title);
  font-size: 3rem;
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.03em;
  background: linear-gradient(135deg, #ffffff 30%, #a5b4fc 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: 1.5rem;
}

.hero-subtitle {
  font-size: 1.15rem;
  color: var(--text-muted);
  max-width: 650px;
  margin: 0 auto 2.5rem;
}

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

/* Features Grid View */
.section-header {
  text-align: center;
  margin-bottom: 3.5rem;
}

.section-title {
  font-family: var(--font-title);
  font-size: 2.25rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
}

.section-subtitle {
  color: var(--text-muted);
  font-size: 1.05rem;
  max-width: 600px;
  margin: 0 auto;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 2rem;
  margin-bottom: 4rem;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 2rem;
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  transition: all var(--transition-normal);
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.feature-card:hover {
  background: var(--bg-card-hover);
  transform: translateY(-5px);
  border-color: var(--border-focus);
  box-shadow: 0 10px 25px -10px var(--primary-glow);
}

.feature-icon-wrapper {
  width: 44px;
  height: 44px;
  border-radius: 8px;
  background: rgba(79, 70, 229, 0.1);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--primary);
  margin-bottom: 0.5rem;
}

.feature-card h3 {
  font-family: var(--font-title);
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--text-main);
}

.feature-card p {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.5;
}

/* Markdown Styling (GitHub-like Premium Render) */
.markdown-body {
  font-family: var(--font-body);
  color: var(--text-main);
  line-height: 1.7;
}

.markdown-body h1,
.markdown-body h2,
.markdown-body h3,
.markdown-body h4 {
  font-family: var(--font-title);
  color: var(--text-main);
  margin-top: 2rem;
  margin-bottom: 1rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.markdown-body h1 {
  font-size: 2.25rem;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 0.5rem;
}

.markdown-body h2 {
  font-size: 1.6rem;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 0.4rem;
}

.markdown-body h3 {
  font-size: 1.25rem;
}

.markdown-body p {
  margin-bottom: 1.25rem;
  font-size: 1.05rem;
  color: #D1D5DB;
}

.markdown-body ul, 
.markdown-body ol {
  margin-bottom: 1.25rem;
  padding-left: 2rem;
}

.markdown-body li {
  margin-bottom: 0.5rem;
  font-size: 1.02rem;
  color: #D1D5DB;
}

.markdown-body li strong {
  color: var(--text-main);
}

.markdown-body a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px dashed var(--accent);
  transition: var(--transition-fast);
}

.markdown-body a:hover {
  color: #22D3EE;
  border-bottom-style: solid;
}

.markdown-body code {
  font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, monospace;
  background-color: rgba(255, 255, 255, 0.06);
  padding: 0.2rem 0.4rem;
  border-radius: 4px;
  font-size: 0.88em;
}

.markdown-body pre {
  margin-bottom: 1.5rem;
  padding: 1.25rem;
  background-color: rgba(17, 24, 39, 0.6);
  border: 1px solid var(--border-color);
  border-radius: 10px;
  overflow-x: auto;
}

.markdown-body pre code {
  padding: 0;
  background-color: transparent;
  font-size: 0.9em;
}

.markdown-body blockquote {
  padding: 0.5rem 1.25rem;
  border-left: 4px solid var(--primary);
  background-color: rgba(79, 70, 229, 0.05);
  color: var(--text-muted);
  border-radius: 0 8px 8px 0;
  margin-bottom: 1.5rem;
}

/* Footer Section */
.app-footer {
  border-top: 1px solid var(--border-color);
  background-color: rgba(11, 15, 25, 0.9);
  padding: 4rem 2rem 2rem;
  margin-top: 6rem;
}

.footer-container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  gap: 3rem;
  justify-content: space-between;
  margin-bottom: 3rem;
}

.footer-brand {
  flex: 1 1 300px;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-family: var(--font-title);
  font-weight: 700;
  font-size: 1.15rem;
}

.footer-desc {
  color: var(--text-muted);
  font-size: 0.92rem;
  max-width: 320px;
}

.footer-links {
  display: flex;
  gap: 4rem;
  flex-wrap: wrap;
}

.footer-column {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.footer-column h4 {
  font-family: var(--font-title);
  font-size: 0.95rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-main);
}

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

.footer-column a {
  text-decoration: none;
  color: var(--text-muted);
  font-size: 0.9rem;
  transition: var(--transition-fast);
}

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

.footer-bottom {
  max-width: 1200px;
  margin: 0 auto;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
}

/* Responsive Breakpoints */
@media (max-width: 768px) {
  .hero-title {
    font-size: 2.25rem;
  }
  
  .mobile-nav-toggle {
    display: block;
  }
  
  .app-nav {
    position: fixed;
    top: 60px;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--bg-main);
    flex-direction: column;
    padding: 3rem 2rem;
    gap: 2rem;
    align-items: stretch;
    transform: translateX(100%);
    transition: transform var(--transition-normal);
  }
  
  .app-nav.open {
    transform: translateX(0);
  }
  
  .nav-list {
    flex-direction: column;
    gap: 1.5rem;
    text-align: center;
  }
  
  .nav-link {
    font-size: 1.15rem;
    display: block;
    padding: 0.75rem;
  }

  .nav-cta {
    width: 100%;
    margin-top: 1rem;
  }
  
  .features-grid {
    grid-template-columns: 1fr;
  }
}

/* Author Links */
.author-link {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px dashed var(--accent);
  transition: var(--transition-fast);
}

.author-link:hover {
  color: #22D3EE;
  border-bottom-style: solid;
}