:root {
     --primary: #ffff00;        /* Yellow - main accent color for headings and highlights */
     --secondary: #ff0000;      /* Red - secondary accent for interactions and emphasis */
     --tertiary: #191970;       /* Midnight Blue - accent for backgrounds and gradients */
     --link: yellow;
     --background: #000000;     /* Black - primary background color */
     --text: #ffffff;           /* White - primary text color */
     
     /* Functional transparency variants */
     --surface: rgba(0, 0, 0, 0.8);           /* Semi-transparent background for cards/sections */
     --border-subtle: rgba(255, 255, 0, 0.3); /* Subtle border using primary color */
     --shadow-glow: rgba(255, 255, 0, 0.2);   /* Glow effect using primary color */
     --border-hover: rgba(255, 0, 0, 0.6);    /* Hover border using secondary color */
     --text-shadow: rgba(255, 255, 0, 0.3);   /* Text shadow using primary color */
 }

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

 body {
     font-family: 'Georgia', serif;
     background: linear-gradient(135deg, var(--background) 0%, var(--tertiary) 50%, var(--background) 100%);
     color: var(--text);
     min-height: 100vh;
     overflow-x: hidden;
 }
 a {
    color: var(--link);
 }

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

 .hero {
     text-align: center;
     padding: 4rem 0;
     position: relative;
 }

 .title {
     font-size: 3rem;
     margin-bottom: 1rem;
     background: linear-gradient(45deg, var(--primary), var(--secondary), var(--primary));
     -webkit-background-clip: text;
     background-clip: text;
     -webkit-text-fill-color: transparent;
     text-shadow: 0 0 30px var(--text-shadow);
 }

 .subtitle {
     font-size: 1.2rem;
     color: var(--text);
     margin-bottom: 2rem;
     font-style: italic;
 }

 .grid {
     display: grid;
     grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
     gap: 3rem;
     margin-top: 4rem;
 }

 .card {
     background: var(--surface);
     border: 1px solid var(--border-subtle);
     border-radius: 15px;
     padding: 2.5rem;
     position: relative;
     transition: all 0.3s ease;
     backdrop-filter: blur(10px);
 }

 .card:hover {
     transform: translateY(-5px);
     border-color: var(--border-hover);
     box-shadow: 0 10px 30px var(--shadow-glow);
 }

 .card::before {
     content: '';
     position: absolute;
     top: 0;
     left: 0;
     right: 0;
     height: 3px;
     background: linear-gradient(90deg, var(--primary), var(--secondary), var(--tertiary));
     border-radius: 15px 15px 0 0;
 }

 .card h2 {
     font-size: 2rem;
     margin-bottom: 1.5rem;
     color: var(--primary);
     position: relative;
 }

 .card p {
     line-height: 1.8;
     margin-bottom: 1.5rem;
     color: var(--text);
 }

 .icon {
     font-size: 3rem;
     margin-bottom: 1rem;
     display: block;
     text-align: center;
 }

 .stars {
     position: fixed;
     top: 0;
     left: 0;
     width: 100%;
     height: 100%;
     pointer-events: none;
     z-index: -1;
 }

 .star {
     position: absolute;
     background: var(--text);
     border-radius: 50%;
     animation: twinkle 3s infinite;
 }

 @keyframes twinkle {

     0%,
     100% {
         opacity: 0.3;
     }

     50% {
         opacity: 1;
     }
 }

 /* Site Header Component */
 .site-header {
     background: var(--surface);
     border-bottom: 1px solid var(--border-subtle);
     backdrop-filter: blur(10px);
     position: sticky;
     top: 0;
     z-index: 1000;
 }

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

 .site-logo {
     display: flex;
     align-items: center;
     gap: 0.75rem;
     color: var(--text);
     text-decoration: none;
     transition: color 0.3s ease;
 }

 .site-logo:hover {
     color: var(--primary);
 }

 .site-icon {
     font-size: 1.5rem;
 }

 .site-name {
     font-size: 1.2rem;
     font-weight: 600;
 }

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

 .nav-link {
     color: var(--text);
     text-decoration: none;
     padding: 0.5rem 1rem;
     border-radius: 6px;
     transition: all 0.3s ease;
     font-size: 0.95rem;
 }

 .nav-link:hover {
     color: var(--primary);
     background: rgba(255, 255, 0, 0.1);
 }

 .nav-link.active {
     color: var(--primary);
     background: var(--border-subtle);
 }

 /* Hamburger Menu */
 .hamburger {
     display: none;
     flex-direction: column;
     gap: 4px;
     background: none;
     border: none;
     padding: 8px;
     cursor: pointer;
     border-radius: 4px;
     transition: background-color 0.3s ease;
 }

 .hamburger:hover {
     background: var(--border-subtle);
 }

 .hamburger span {
     width: 24px;
     height: 2px;
     background: var(--text);
     border-radius: 2px;
     transition: all 0.3s ease;
 }

 .hamburger.active span:nth-child(1) {
     transform: rotate(45deg) translate(6px, 6px);
 }

 .hamburger.active span:nth-child(2) {
     opacity: 0;
 }

 .hamburger.active span:nth-child(3) {
     transform: rotate(-45deg) translate(6px, -6px);
 }

 /* Legacy breadcrumb styles (keeping for compatibility) */
 .breadcrumb {
     padding: 1rem 2rem;
     background: var(--surface);
     border-bottom: 1px solid var(--border-subtle);
 }

 .breadcrumb a {
     color: var(--primary);
     text-decoration: none;
     transition: color 0.3s ease;
 }

 .breadcrumb a:hover {
     color: var(--secondary);
 }

 /* Subsection preview styles */
 .subsections {
     margin-top: 1.5rem;
     padding-top: 1.5rem;
     border-top: 1px solid var(--border-subtle);
 }

 .subsection-preview {
     display: flex;
     align-items: center;
     gap: 0.5rem;
     margin-bottom: 0.75rem;
     font-size: 0.9rem;
     color: var(--text);
     opacity: 0.8;
 }

 .subsection-icon {
     font-size: 1.2rem;
     width: 2rem;
     text-align: center;
 }

 /* Click hint for interactive cards */
 .click-hint {
     margin-top: 1rem;
     padding-top: 1rem;
     border-top: 1px solid var(--border-subtle);
     font-size: 0.9rem;
     text-align: center;
     opacity: 0.7;
     transition: opacity 0.3s ease;
 }

 .click-hint a {
     color: var(--primary);
     text-decoration: none;
     transition: color 0.3s ease;
 }

 .click-hint a:hover {
     color: var(--secondary);
 }

 .card:hover .click-hint {
     opacity: 1;
 }

 /* Hover effect for clickable cards */
 .card[style*="cursor: pointer"]:hover {
     transform: translateY(-8px);
     border-color: var(--primary);
 }

.navbar {
    display: flex;
    gap: 1rem;
    justify-content: space-between;
    align-items: center;
}

@media (max-width: 768px) {
     .grid {
         grid-template-columns: 1fr;
         gap: 2rem;
     }

     .title {
         font-size: 2rem;
     }

     .card {
         padding: 2rem;
     }

     .breadcrumb {
         padding: 1rem;
     }

     /* Mobile Header */
     .header-content {
         padding: 1rem;
     }

     .site-name {
         font-size: 1.1rem;
     }

     .main-nav {
         position: absolute;
         top: 100%;
         left: 0;
         right: 0;
         background: var(--surface);
         border-bottom: 1px solid var(--border-subtle);
         flex-direction: column;
         gap: 0;
         padding: 1rem 0;
         transform: translateY(-100%);
         opacity: 0;
         visibility: hidden;
         transition: all 0.3s ease;
     }

     .main-nav.active {
         transform: translateY(0);
         opacity: 1;
         visibility: visible;
     }

     .nav-link {
         padding: 1rem 2rem;
         width: 100%;
         text-align: left;
         border-radius: 0;
     }

     .hamburger {
         display: flex;
     }
}