@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@300;400;500;600;700&display=swap'); 
        @import url('https://fonts.googleapis.com/css2?family=Roboto+Mono:wght@400;700&display=swap'); 

        /* --- Monochromatic Color Palette --- */
        :root {
            --bg-dark: #000; 
            --bg-light: #111; 
            --text-light: #fff;
            --neon-green: #39ff14; 
            --border-color: #444; 
            --correct-color: #1aff00; 
            --incorrect-color: #ff3333; 
            --stop-codon-color: #900;
            
            --dna-color: #1e90ff; 
            --mrna-color: var(--neon-green);
            --protein-color: #ffd700; 
        }
        
        /* --- GLOBAL FADE-IN ANIMATION (NEW) --- */
        @keyframes pageFadeIn {
            from { opacity: 0; }
            to { opacity: 1; }
        }

        body {
            font-family: 'Poppins', sans-serif;
            display: flex;
            flex-direction: column;
            justify-content: flex-start;
            align-items: center;
            min-height: 100vh;
            background-color: var(--bg-dark); 
            color: var(--text-light);
            margin: 0;
            overflow-x: hidden; 
            padding-top: 20px;
            padding-bottom: 20px;
            
            /* Apply Fade-In to the Body */
            opacity: 0; 
            animation: pageFadeIn 0.8s ease-out forwards;
        }

        body::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: linear-gradient(to right, rgba(255, 255, 255, 0.05) 1px, transparent 1px),
                        linear-gradient(to bottom, rgba(255, 255, 255, 0.05) 1px, transparent 1px);
            background-size: 50px 50px;
            z-index: 1;
        }

        /* --- Navigation Bar Styles --- */
        .nav-bar {
            width: 100%; 
            max-width: none; 
            height: 60px;
            background-color: var(--bg-light); 
            border-bottom: 1px solid var(--border-color); 
            box-shadow: none; 
            display: flex;
            justify-content: center;
            align-items: center;
            padding: 0 20px; 
            position: relative;
            z-index: 20;
            margin-bottom: 20px; 
            border-radius: 0; 
        }

        .nav-bar a {
            color: var(--text-light);
            text-decoration: none;
            font-weight: 500;
            font-size: 1.1em;
            padding: 10px 20px;
            margin: 0 10px;
            transition: color 0.3s;
        }

        .nav-bar a:hover {
            color: var(--glow-color); 
            text-shadow: none; 
        }
        .nav-bar .current-page {
            color: var(--neon-green);
            text-shadow: 0 0 5px var(--neon-green);
            font-weight: 700;
        }


        .lab-container {
            background-color: transparent; 
            padding: 40px;
            border-radius: 5px;
            width: 95%;
            max-width: 900px;
            position: relative;
            z-index: 10;
            height: auto; 
            min-height: auto; 
            transition: height 0.5s ease-out; 
            overflow: hidden; 
        }

        /* Inner Dark Background */
        .lab-container::after {
            content: ''; position: absolute; top: 2px; left: 2px; right: 2px; bottom: 2px; z-index: -1;
            background: var(--bg-light); 
            border-radius: 5px;
        }

        /* ANIMATED BORDER STYLES */
        @property --angle{
            syntax: '<angle>';
            initial-value: 0deg;
            inherits: false;
        }
        .lab-container::before {
            content: ''; position: absolute; top: 0; left: 0; right: 0; bottom: 0; z-index: -2;
            margin: -2px; border-radius: 5px; 
            background: conic-gradient(from var(--angle), transparent 50%, var(--neon-green), var(--neon-green));
            animation: rotateGlow 5s linear infinite; filter: none; 
        }

        @keyframes rotateGlow { 
            from { --angle: 0deg; }
            to { --angle: 360deg; } 
        }
        
        h1, h2, h3 { 
            font-family: 'Poppins', sans-serif; 
            color: var(--neon-green); 
            text-shadow: 0 0 8px var(--neon-green); 
            letter-spacing: 2px;
            margin-bottom: 20px;
            text-align: center;
        }

        .lab-content p { 
            color: var(--text-light);
            text-shadow: none;
            text-align: left;
            margin-bottom: 15px;
        }

        /* INPUT AREA STYLES */
        .lab-content textarea {
            width: 100%;
            min-height: 50px;
            background-color: var(--bg-dark);
            color: var(--text-light);
            border: 1px solid var(--border-color);
            padding: 10px;
            box-sizing: border-box;
            font-family: 'Roboto Mono', monospace; 
            font-size: 1.2em;
            margin-bottom: 15px;
            resize: vertical;
        }
        
        /* Mutation Button Container for Single Row Centered Layout */
        .mutation-controls {
            display: flex;
            justify-content: center; 
            align-items: center;
            gap: 10px;
            margin-bottom: 10px; 
            flex-wrap: wrap; 
        }
        .mutation-controls button {
            flex-grow: 1;
            width: auto; 
            min-width: 150px;
        }


        /* OUTPUT AREA STYLES*/
        .lab-output {
            margin-top: 30px;
            padding-top: 15px;
            border-top: 2px solid var(--border-color);
            opacity: 0;
            transform: translateY(20px);
            transition: opacity 0.5s ease-out, transform 0.5s ease-out;
        }
        .lab-output.pop-in {
            opacity: 1;
            transform: translateY(0);
        }

        .lab-output > div {
            padding: 12px 0;
            border-bottom: 1px dashed var(--border-color);
            display: flex;
            align-items: center;
            text-align: left;
        }

        .lab-output label {
            width: 120px; 
            font-weight: 600;
            color: var(--text-light);
            text-shadow: none;
            font-family: 'Poppins', sans-serif;
            flex-shrink: 0;
        }
        
        /* SEQUENCE SPECIFIC STYLES */
        .sequence {
            flex-grow: 1;
            font-family: 'Roboto Mono', monospace;
            font-size: 1.1em;
            letter-spacing: 1px;
            word-break: break-all;
        }

        #dna-output-div .sequence { color: var(--dna-color); }
        #mrna-output-div .sequence { color: var(--mrna-color); }
        
        #mutation-effect-div { 
            border-bottom: none; 
            font-weight: 600;
            font-size: 1.1em;
        }
        .mutation-success {
             color: var(--correct-color);
             text-shadow: 0 0 3px var(--correct-color);
        }
        .mutation-error {
             color: var(--incorrect-color);
             text-shadow: 0 0 3px var(--incorrect-color);
        }
        #message-area {
            color: var(--incorrect-color);
            font-weight: 600;
            margin-bottom: 15px;
            text-align: center;
            min-height: 20px; 
        }


        /* MUTATION VISUALS */
        .mutation-highlight {
            color: var(--incorrect-color);
            font-weight: 700;
            text-shadow: 0 0 5px var(--incorrect-color);
            background-color: rgba(255, 51, 51, 0.1);
            padding: 2px 0;
            border-radius: 2px;
        }

        /* AMINO ACID CHAIN VISUALS */
        .lab-amino-chain {
            display: flex;
            flex-wrap: wrap;
            margin-top: 5px;
            font-family: 'Roboto Mono', monospace;
            gap: 5px 8px; 
        }
        .amino-acid {
            padding: 3px 6px;
            border-radius: 4px;
            background-color: rgba(255, 215, 0, 0.1); 
            color: var(--protein-color);
            font-weight: 500;
            white-space: nowrap;
            box-shadow: 0 0 3px rgba(255, 215, 0, 0.5); 
        }
        .amino-acid.missense {
            background-color: rgba(255, 51, 51, 0.2);
            color: var(--incorrect-color);
            box-shadow: 0 0 5px var(--incorrect-color);
        }
        .amino-acid.nonsense {
            background-color: var(--stop-codon-color);
            color: var(--text-light);
            font-weight: bold;
            box-shadow: 0 0 8px var(--stop-codon-color);
        }
        #protein-output-div .lab-output label {
            align-self: flex-start;
        }

        /* NEON BUTTON STYLING (General) */
        .lab-content button { 
            padding: 15px;
            background-color: #0e0d0d; border: 1px solid var(--neon-green); color: var(--neon-green); 
            font-size: 1.1em; cursor: pointer; font-weight: bold; 
            box-shadow: 0 0 8px var(--neon-green); 
            transition: background-color 0.3s, box-shadow 0.3s, transform 0.2s;
        }
        .lab-content button:hover {
            background-color: var(--neon-green); 
            box-shadow: 0 0 20px var(--neon-green); 
            color: var(--bg-dark); 
            transform: translateY(-2px);
        }

        @media (max-width: 768px) {
            .nav-bar {
                flex-direction: column; 
                height: auto;          
                padding: 15px 0;       
            }

            .nav-bar a {
                margin: 8px 0;          
                width: 100%;          
                text-align: center;     
            }
        }