:root {
            --primary: #1a56db;
            --primary-dark: #1e429f;
            --secondary: #3b82f6;
            --text: #1f2937;
            --text-light: #6b7280;
            --bg: #f8fafc;
            --card-bg: #ffffff;
            --tag-bg: #eef2ff;
            --tag-text: #3730a3;
            --shadow: rgba(0, 0, 0, 0.1);
            --header-bg: rgba(255, 255, 255, 0.95);
            --transition: all 0.3s ease;
            --border-radius: 12px;
            --spacing-xs: 0.5rem;
            --spacing-sm: 1rem;
            --spacing-md: 1.5rem;
            --spacing-lg: 2rem;
            --spacing-xl: 3rem;
        }
        
        .dark-theme {
            --primary: #3b82f6;
            --primary-dark: #2563eb;
            --secondary: #60a5fa;
            --text: #f3f4f6;
            --text-light: #d1d5db;
            --bg: #111827;
            --card-bg: #1f2937;
            --tag-bg: #374151;
            --tag-text: #e5e7eb;
            --shadow: rgba(0, 0, 0, 0.25);
            --header-bg: rgba(31, 41, 55, 0.95);
        }
        
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            transition: var(--transition);
        }
        
        body {
            font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
            background: var(--bg);
            color: var(--text);
            line-height: 1.6;
            padding-bottom: 2rem;
            transition: background-color 0.5s ease;
            position: relative;
            overflow-x: hidden;
        }
        
        body::before {
            content: "";
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: radial-gradient(circle at 25% 25%, rgba(26, 86, 219, 0.03) 0%, transparent 50%),
                radial-gradient(circle at 75% 75%, rgba(59, 130, 246, 0.03) 0%, transparent 50%);
            animation: subtleFloat 15s ease-in-out infinite;
            z-index: -1;
            pointer-events: none;
        }
        
        @keyframes subtleFloat {
            0%, 100% {
                opacity: 1;
                transform: translateY(0px);
            }
            50% {
                opacity: 0.8;
                transform: translateY(-10px);
            }
        }
        
        header {
            background: var(--header-bg);
            backdrop-filter: blur(10px);
            padding: var(--spacing-md);
            box-shadow: 0 4px 12px var(--shadow);
            position: static;
            width: 100%;
        }
        
        .header-content {
            max-width: 1200px;
            margin: 0 auto;
            text-align: center;
        }
        
        h1 {
            background: linear-gradient(90deg, var(--primary), var(--secondary), var(--primary));
            -webkit-background-clip: text;
            background-clip: text;
            color: transparent;
            font-size: 3rem;
            font-weight: 800;
            letter-spacing: -1px;
            text-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
            animation: shimmer 3s ease-in-out infinite alternate;
            position: relative;
            display: inline-block;
            margin-bottom: 0.5rem;
        }
        
        @keyframes shimmer {
            0% {
                background-position: -200% center;
            }
            100% {
                background-position: 200% center;
            }
        }
        
        h1::after {
            content: "";
            position: absolute;
            bottom: -8px;
            left: 0;
            width: 100%;
            height: 3px;
            background: linear-gradient(90deg, var(--primary), var(--secondary), var(--primary));
            border-radius: 2px;
            transform: scaleX(0);
            transform-origin: center;
            animation: underline 3s ease-in-out infinite;
        }
        
        @keyframes underline {
            0%, 100% {
                transform: scaleX(0.2);
            }
            50% {
                transform: scaleX(1);
            }
        }
        
        .subheading {
            color: var(--text-light);
            font-size: 1.2rem;
            margin-top: 0.5rem;
            font-weight: 400;
            max-width: 600px;
            margin-left: auto;
            margin-right: auto;
            animation: fadeIn 2s ease-out;
        }
        
        @keyframes fadeIn {
            from {
                opacity: 0;
                transform: translateY(10px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }
        
        /* Toggle button in top-right corner */
        .toggle-container {
            position: fixed;
            top: 1rem;
            right: 1rem;
            z-index: 200;
        }
        
        .toggle-switch {
            position: relative;
            display: inline-block;
            width: 50px;
            height: 26px;
        }
        
        .toggle-switch input {
            opacity: 0;
            width: 0;
            height: 0;
        }
        
        .slider {
            position: absolute;
            cursor: pointer;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: linear-gradient(135deg, var(--primary), var(--primary-dark));
            transition: .4s;
            border-radius: 34px;
        }
        
        .slider:before {
            position: absolute;
            content: "";
            height: 20px;
            width: 20px;
            left: 3px;
            bottom: 3px;
            background-color: white;
            transition: .4s;
            border-radius: 50%;
        }
        
        input:checked + .slider {
            background: linear-gradient(135deg, var(--secondary), var(--primary));
        }
        
        input:checked + .slider:before {
            transform: translateX(24px);
        }
        
        /* Filter Buttons */
        .filter-container {
            max-width: 1200px;
            margin: var(--spacing-lg) auto;
            padding: 0 var(--spacing-md);
            text-align: center;
        }
        
        .filter-buttons {
            display: inline-flex;
            background: var(--card-bg);
            border-radius: 50px;
            padding: 8px;
            box-shadow: 0 4px 12px var(--shadow);
            gap: 4px;
            flex-wrap: wrap;
            justify-content: center;
        }
        
        .filter-btn {
            background: transparent;
            border: none;
            padding: 12px 24px;
            border-radius: 40px;
            font-size: 0.9rem;
            font-weight: 600;
            color: var(--text-light);
            cursor: pointer;
            transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
            white-space: nowrap;
            position: relative;
            overflow: hidden;
        }
        
        .filter-btn::before {
            content: "";
            position: absolute;
            top: 0;
            left: -100%;
            width: 100%;
            height: 100%;
            background: linear-gradient(90deg, transparent, rgba(26, 86, 219, 0.1), transparent);
            transition: left 0.6s ease;
        }
        
        .filter-btn:hover::before {
            left: 100%;
        }
        
        .filter-btn:hover {
            color: var(--primary);
            background: var(--tag-bg);
            transform: translateY(-2px);
        }
        
        .filter-btn.active {
            background: linear-gradient(135deg, var(--primary), var(--primary-dark));
            color: white;
            box-shadow: 0 4px 12px rgba(26, 86, 219, 0.4);
            transform: translateY(-2px);
        }
        
        .container {
            max-width: 1200px;
            margin: var(--spacing-lg) auto;
            padding: 0 var(--spacing-md);
        }
        
        .papers-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: var(--spacing-lg);
        }
        
        .paper-card {
            background: var(--card-bg);
            border-radius: var(--border-radius);
            overflow: hidden;
            box-shadow: 0 8px 16px var(--shadow);
            transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
            display: flex;
            flex-direction: column;
            height: 100%;
            position: relative;
        }
        
        .paper-card:hover {
            box-shadow: 0 12px 24px var(--shadow);
        }
        
        .paper-card.hidden {
            opacity: 0;
            transform: scale(0.8);
            pointer-events: none;
        }
        
        .paper-content {
            padding: var(--spacing-md);
            display: flex;
            flex-direction: column;
            flex-grow: 1;
        }
        
        .paper-title {
            font-size: 1.4rem;
            margin-bottom: 0.8rem;
            color: var(--text);
            font-weight: 600;
            line-height: 1.3;
        }
        
        .paper-authors {
            color: var(--text-light);
            font-style: italic;
            margin-bottom: 0.8rem;
            font-size: 0.9rem;
        }
        
        .paper-conference {
            color: var(--primary);
            font-weight: 600;
            margin-bottom: 1rem;
            font-size: 0.9rem;
        }
        
        .paper-abstract {
            color: var(--text-light);
            margin-bottom: 1.2rem;
            flex-grow: 1;
            line-height: 1.6;
            font-size: 0.95rem;
        }
        
        .paper-tags {
            display: flex;
            flex-wrap: wrap;
            gap: 0.6rem;
            margin-bottom: 1.5rem;
        }
        
        .tag {
            background: var(--tag-bg);
            color: var(--tag-text);
            padding: 0.15rem 0.5rem;
            border-radius: 14px;
            font-size: 0.68rem;
            font-weight: 500;
            transition: all 0.3s ease;
            position: relative;
            overflow: hidden;
        }
        
        .tag::before {
            content: "";
            position: absolute;
            top: 0;
            left: -100%;
            width: 100%;
            height: 100%;
            background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
            transition: left 0.5s ease;
        }
        
        .paper-card:hover .tag::before {
            left: 100%;
        }
        
        .tag:hover {
            transform: scale(1.1);
            background: var(--primary);
            color: white;
        }
        
        .paper-links {
            display: flex;
            gap: 1rem;
        }
        
        .paper-link {
            display: flex;
            align-items: center;
            gap: 0.4rem;
            padding: 0.6rem 1.2rem;
            border-radius: 6px;
            text-decoration: none;
            font-weight: 600;
            font-size: 0.95rem;
            transition: transform 0.2s ease, box-shadow 0.2s ease;
        }
        
        .view-pdf-link {
            background: linear-gradient(135deg, var(--primary), var(--primary-dark));
            color: white;
        }
        
        .download-pdf-link {
            background: transparent;
            color: var(--primary);
            border: 1.5px solid var(--primary);
        }
        
        .paper-link:hover {
            transform: translateY(-2px);
            box-shadow: 0 4px 8px var(--shadow);
        }
        
        .view-pdf-link:hover {
            background: linear-gradient(135deg, var(--primary-dark), var(--primary));
        }
        
        .download-pdf-link:hover {
            background: var(--primary);
            color: white;
        }
        
        /* Responsive Design */
        @media (max-width: 1024px) {
            .papers-grid {
                grid-template-columns: repeat(2, 1fr);
                gap: var(--spacing-md);
            }
            
            h1 {
                font-size: 2.5rem;
            }
        }
        
        @media (max-width: 768px) {
            .papers-grid {
                grid-template-columns: repeat(2, 1fr);
                gap: var(--spacing-sm);
            }
            
            .paper-content {
                padding: var(--spacing-sm);
            }
            
            .paper-title {
                font-size: 1.2rem;
            }
            
            .paper-abstract {
                font-size: 0.9rem;
            }
            
            .paper-link {
                padding: 0.5rem 1rem;
                font-size: 0.85rem;
            }
            
            .filter-buttons {
                padding: 6px;
                gap: 2px;
            }
            
            .filter-btn {
                padding: 10px 16px;
                font-size: 0.8rem;
            }
            
            h1 {
                font-size: 2.2rem;
            }
            
            .subheading {
                font-size: 1.1rem;
            }
        }
        
        @media (min-width: 601px) {
            .view-more-overlay {
                display: none !important;
            }
        }
        
@media (max-width: 600px) {
    header {
        position: static;
        width: 100vw;
        padding: var(--spacing-sm);
    }
    
    h1 {
        font-size: 2rem;
    }
    
    .subheading {
        font-size: 1rem;
    }
    
    .papers-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-sm);
    }
    
    /* Compact, centered filter panel for mobile (only two buttons) */
    .filter-container {
        padding: 0 0.5rem;
        display: flex;
        justify-content: center; /* center the whole panel */
        align-items: center;
        overflow: visible;       /* avoid extra horizontal space */
    }
    
    .filter-buttons {
        display: inline-flex;
        justify-content: center; /* center the buttons inside */
        align-items: center;
        gap: 8px;                 /* small gap between two buttons */
        padding: 6px;             /* tighten padding */
        border-radius: 999px;
        background: var(--card-bg);
        box-shadow: 0 6px 14px var(--shadow);
        width: auto;              /* shrink to content */
        min-width: 0;
    }
    
    .filter-btn {
        padding: 8px 14px;        /* smaller touch-friendly size */
        border-radius: 22px;
        font-size: 0.82rem;
        white-space: nowrap;
        flex: none;               /* prevent stretching */
    }
    
    .container {
        padding: 0 var(--spacing-sm);
    }
    
    .paper-card {
        position: relative;
        overflow: hidden;
        max-height: 320px;
        transition: max-height 0.5s cubic-bezier(0.4, 0, 0.2, 1);
    }
    
    .paper-card .view-more-overlay {
        position: absolute;
        bottom: 0;
        left: 0;
        right: 0;
        height: 80px;
        background: linear-gradient(to top, var(--card-bg) 0%, var(--card-bg) 40%, rgba(255, 255, 255, 0) 100%);
        display: flex;
        align-items: flex-end;
        justify-content: center;
        padding-bottom: 15px;
        cursor: pointer;
        transition: all 0.3s ease;
        z-index: 10;
    }
    
    .dark-theme .paper-card .view-more-overlay {
        background: linear-gradient(to top, var(--card-bg) 0%, var(--card-bg) 40%, rgba(31, 41, 55, 0) 100%);
    }
    
    .view-more-btn {
        background: linear-gradient(135deg, var(--primary), var(--primary-dark));
        color: white;
        border: none;
        padding: 8px 16px;
        border-radius: 20px;
        font-size: 0.8rem;
        font-weight: 600;
        cursor: pointer;
        box-shadow: 0 4px 12px rgba(26, 86, 219, 0.3);
        transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
        backdrop-filter: blur(10px);
    }
    
    .view-more-btn:hover {
        transform: translateY(-2px) scale(1.05);
        box-shadow: 0 6px 16px rgba(26, 86, 219, 0.4);
    }
    
    .view-more-btn:active {
        transform: translateY(0) scale(0.98);
    }
}
        @media (max-width: 480px) {
            .papers-grid {
                grid-template-columns: 1fr;
                gap: var(--spacing-sm);
            }
            
            .paper-title {
                font-size: 1.1rem;
            }
            
            .paper-abstract {
                font-size: 0.9rem;
            }
            
            h1 {
                font-size: 1.8rem;
            }
        }
        
        /* Full-screen modal styles for small devices */
        .paper-modal {
            position: fixed;
            top: 0;
            left: 0;
            width: 100vw;
            height: 100vh;
            background: var(--bg);
            z-index: 1000;
            display: none;
            flex-direction: column;
            overflow-y: auto;
            -webkit-overflow-scrolling: touch;
        }
        
        .modal-header {
            position: sticky;
            top: 0;
            background: var(--header-bg);
            backdrop-filter: blur(10px);
            padding: var(--spacing-sm) var(--spacing-md);
            display: flex;
            align-items: center;
            gap: var(--spacing-sm);
            box-shadow: 0 2px 8px var(--shadow);
            z-index: 1001;
            min-height: 60px;
        }
        
        .modal-back-btn {
            background: var(--primary);
            color: white;
            border: none;
            width: 40px;
            height: 40px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            cursor: pointer;
            transition: all 0.3s ease;
            font-size: 1rem;
            flex-shrink: 0;
        }
        
        .modal-back-btn:hover {
            background: var(--primary-dark);
            transform: scale(1.1);
        }
        
        .modal-title {
            color: var(--text);
            font-size: 1.2rem;
            margin: 0;
            font-weight: 600;
        }
        
        .modal-content {
            flex: 1;
            padding: 0.5rem;
            display: flex;
            flex-direction: column;
            justify-content: flex-start;
            align-items: center;
            min-height: calc(100vh - 60px);
            max-height: calc(100vh - 60px);
            overflow-y: auto;
        }
        
        .modal-paper-card {
            background: var(--card-bg);
            border-radius: var(--border-radius);
            overflow: hidden;
            box-shadow: 0 8px 16px var(--shadow);
            width: 100%;
            max-width: 100%;
            margin: 0;
            display: flex;
            flex-direction: column;
            height: fit-content;
            min-height: auto;
        }
        
        .modal-paper-card .paper-content {
            padding: var(--spacing-md);
            display: flex;
            flex-direction: column;
            gap: 0.8rem;
        }
        
        .modal-paper-card .paper-title {
            font-size: 1.3rem;
            margin-bottom: 0;
            line-height: 1.3;
            word-wrap: break-word;
        }
        
        .modal-paper-card .paper-abstract {
            font-size: 0.9rem;
            line-height: 1.5;
            margin-bottom: 0;
            color: var(--text-light);
        }
        
        .modal-paper-card .paper-tags {
            margin-bottom: 0;
            display: flex;
            flex-wrap: wrap;
            gap: 0.5rem;
        }
        
        .modal-paper-card .tag {
            font-size: 0.7rem;
            padding: 0.2rem 0.6rem;
            border-radius: 12px;
        }
        
        .modal-paper-card .paper-links {
            display: flex;
            flex-direction: column;
            gap: 0.6rem;
            margin-top: 0.4rem;
        }
        
        .modal-paper-card .paper-link {
            padding: 0.7rem 1.2rem;
            font-size: 0.9rem;
            text-align: center;
            justify-content: center;
        }