:root {
     --white-bg: #ffffff;
     --light-bg: #f5f7fa;
     --code-bg: #1a1a2e;
     --code-text: #ffffff;
     --text-color: #1e293b;
     --highlight-color: #4361ee;
     --secondary-color: #3f37c9;
     --gray-text: #64748b;
     --border-color: #e2e8f0;
     --card-bg: #ffffff;
     --section-title: #e63946;
     --card-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
     --header-gradient: linear-gradient(135deg, #4361ee, #3a0ca3);
 }

 * {
     margin: 0;
     padding: 0;
     box-sizing: border-box;
     font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
         Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif;
 }

 body {
     background-color: var(--light-bg);
     color: var(--text-color);
     line-height: 1.6;
 }

 main {
     max-width: 1200px;
     margin: 0 auto;
     padding: 2rem 1rem;
 }

 .header-container {
     background-image: var(--header-gradient);
     padding: 2.5rem 1rem;
     border-radius: 10px;
     margin-bottom: 1.5rem;
     text-align: center;
     box-shadow: var(--card-shadow);
 }

 .title {
     color: white;
     margin-bottom: 0.5rem;
     font-size: 2.5rem;
     font-weight: 700;
 }

 .subtitle {
     color: rgba(255, 255, 255, 0.9);
     margin-bottom: 0.3rem;
     font-size: 1rem;
     max-width: 700px;
     margin-left: auto;
     margin-right: auto;
 }

 .cards-container {
     display: grid;
     grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
     gap: 1.5rem;
 }

 .card {
     background-color: var(--card-bg);
     border-radius: 10px;
     overflow: hidden;
     box-shadow: var(--card-shadow);
     padding: 1rem;
     display: flex;
     flex-direction: column;
     transition: transform 0.3s ease, box-shadow 0.3s ease;
     cursor: default;
 }

 .card:hover {
     transform: translateY(-10px);
     box-shadow: 0 12px 24px rgba(0, 0, 0, 0.25);
     cursor: pointer;
 }

 .section-title {
     display: flex;
     align-items: center;
     gap: 0.5rem;
     color: var(--section-title);
     margin-bottom: 0.3rem;
     font-size: 1.5rem;
     font-weight: bold;
 }

 .topic-name {
     color: red;
     font-weight: bold;
     margin-top: 1rem;
     margin-bottom: 0.3rem;
     font-size: 1rem;
 }

 pre {
     background-color: var(--code-bg);
     color: var(--code-text);
     padding: 1rem;
     border-radius: 8px;
     overflow-x: auto;
     margin: 0.2rem 0 0 0;
     font-family: "Consolas", "Monaco", monospace;
     font-size: 0.9rem;
     line-height: 1.5;
     box-shadow: inset 0 1px 5px rgba(0, 0, 0, 0.2);
     white-space: pre-wrap;
     flex-grow: 1;
     user-select: text;
 }

 /* Updated Footer Styles - Horizontally Centered */
 .footer {
     text-align: center;
     padding: 2rem 0;
     margin-top: 3rem;
     color: var(--gray-text);
     font-size: 0.9rem;
     border-top: 1px solid var(--border-color);
     display: flex;
     flex-direction: column;
     align-items: center;
     justify-content: center;
 }

 .footer p {
     margin: 0.5rem 0;
 }

 /* Floating Social Media Icons */
 .social-icons-container {
     display: flex;
     justify-content: center;
     align-items: center;
     padding: 20px 0;
     /* Removed width: 100% and background-color */
 }

 .social-icons {
     display: flex;
     flex-wrap: wrap;
     justify-content: center;
     align-items: center;
     gap: 20px;
 }

 .social-icons a {
     color: inherit;
     text-decoration: none;
     transition: transform 0.3s ease, color 0.3s ease;
     display: flex;
     justify-content: center;
     align-items: center;
 }

 .social-icons a:hover {
     transform: translateY(-5px);
     opacity: 0.8;
 }

 .social-icons a i {
     font-size: 2rem;
 }

 @media (max-width: 576px) {
     .social-icons {
         gap: 15px;
     }

     .social-icons a i {
         font-size: 1.5rem;
     }
 }

 @media (max-width: 375px) {
     .social-icons {
         gap: 10px;
     }

     .social-icons a i {
         font-size: 1.25rem;
     }
 }

 /* ----------------------------------------- */
 /* popUp Animation  */
 /* ----------------------------------------- */
 /* General Reset */
 * {
     margin: 0;
     padding: 0;
     box-sizing: border-box;
 }

 /* Popup container styling */
 #popup {
     position: fixed;
     top: 50%;
     left: 50%;
     transform: translate(-50%, -50%) scale(0);
     /* Start with scale 0 for animation */
     width: 90%;
     /* Default for smaller screens */
     max-width: 600px;
     /* Constrain max width for larger screens */
     background-color: #fff;
     border-radius: 8px;
     box-shadow: 0 4px 6px rgba(0, 0, 0, 0.2);
     z-index: 1000;
     text-align: center;
     opacity: 0;
     /* Hidden by default */
     transition: transform 1s ease, opacity 1s ease;
     /* Smooth animation */
 }

 /* Show popup with animation */
 #popup.show {
     transform: translate(-50%, -50%) scale(1);
     /* Scale to full size */
     opacity: 1;
     /* Fully visible */
 }

 /* Popup image */
 #popup img {
     width: 100%;
     /* Make the image fully responsive */
     border-radius: 8px;
 }

 /* Close button styling */
 #close-btn {
     position: absolute;
     top: 10px;
     right: 10px;
     background: none;
     border: none;
     font-size: 24px;
     font-weight: bold;
     cursor: pointer;
     color: #555;
 }