* { margin: 0; padding: 0; box-sizing: border-box; }
        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            min-height: 100vh;
            padding: 20px;
        }
        .container { max-width: 1400px; margin: 0 auto; }
        header { text-align: center; color: white; margin-bottom: 40px; }
        h1 { font-size: 2.5em; margin-bottom: 10px; text-shadow: 2px 2px 4px rgba(0,0,0,0.3); }
        .subtitle { font-size: 1.2em; opacity: 0.9; }
        .roadmap-grid .roadmap-card h3 { color: #2d3748; font-size:1.05rem; }
        .roadmap-card ul { line-height:1.45; }
        @media (max-width:720px) {
        .roadmap-grid { grid-template-columns: 1fr; }
        }
        .cta,
        .cta-outline {
            border-radius: 22px;
            font-weight: 800;
            cursor: pointer;
            transition:
                background 0.3s ease,
                color 0.3s ease,
                box-shadow 0.3s ease,
                transform 0.25s ease;
        }

        /* PRIMARY CTA — BIG */
        .cta {
            padding: 16px 32px;              
            font-size: 1.05rem;             
            letter-spacing: 0.4px;

            border: none;
            background: #667eea;
            color: white;

            box-shadow:
                0 14px 30px rgba(102,126,234,0.35),
                inset 0 1px 0 rgba(255,255,255,0.35);
        }

        .cta:hover {
            background: #ea6f66;
            box-shadow:
                0 22px 44px rgba(234,111,102,0.45);
            transform: translateY(-4px) scale(1.03);
            border: 2px solid #667eea
        }

        /* SECONDARY CTA — smaller but related */
        .cta-outline {
            padding: 12px 22px;
            font-size: 0.9rem;

            background: transparent;
            color: #667eea;

            border: 2px solid #667eea; 
            box-sizing: border-box;  
        }

        .cta-outline:hover {
            background: #4CAF50; 
            border-color: #4CAF50;
            color: rgb(255, 255, 255);
            transition: all 0.3s;
      
        }
        .tabs {
                display: grid;
                grid-template-columns: repeat(auto-fit, minmax(160px, max-content));
                gap: 12px;
                margin-bottom: 30px;
                justify-content: center;
            }

            /* =========================
            Base tab
            ========================= */
        .tab {
                min-height: 48px;
                padding: 12px 24px;
                line-height: 1;
                display: flex;
                align-items: center;
                justify-content: center;
                padding-top: 13px;
                padding-bottom: 11px;
                text-align: center;
                white-space: nowrap;

                background: rgba(255, 255, 255, 0.18);
                border: 1px solid rgba(255, 255, 255, 0.45);
                border-radius: 25px;

                color: #f5f6fa;
                font-size: 0.8em;
                font-weight: 500;

                cursor: pointer;
                box-sizing: border-box;
                position: relative;

                backdrop-filter: blur(12px);

                transition:
                    background 0.25s ease,
                    color 0.25s ease,
                    box-shadow 0.25s ease,
                    transform 0.2s ease;
            }

            /* Reserve bold width */
        .tab::before {
                content: attr(data-label);
                font-weight: 700;
                visibility: hidden;
                position: absolute;
            }

            /* =========================
            Hover (near-active)
            ========================= */
        .tab:hover {
                background: rgba(40, 40, 42, 0.9);
                color: #ffffff;
                transform: translateY(-1px);

                box-shadow:
                    0 10px 26px rgba(0, 0, 0, 0.45);
            }

            /* =========================
            Active
            ========================= */
        .tab.active {
                background: rgba(28, 28, 30, 0.98);
                color: #ffffff;
                font-weight: 700;

                transform: none;

                box-shadow:
                    0 14px 34px rgba(0, 0, 0, 0.55);
            }


         .tab::after {
                content: "";
                position: absolute;
                inset: 0;
                border-radius: 25px;
                pointer-events: none;

                box-shadow: 0 0 0 0 rgba(255, 204, 128, 0);
                transition: box-shadow 0.25s ease;
            }

        .tab:hover::after {
                box-shadow: 0 0 0 2px rgba(255, 204, 128, 0.45);
            }

        .tab.active::after {
                box-shadow: 0 0 0 2px rgba(255, 204, 128, 0.95);
            }





        .content { background: white; border-radius: 20px; padding: 40px; box-shadow: 0 20px 60px rgba(0,0,0,0.3); }
        .section { display: none; }
        .section.active { display: block; animation: fadeIn 0.5s; }
        @keyframes fadeIn { from { opacity: 0; transform: translateY(20px); } to { opacity: 1; transform: translateY(0); } }
        .title {  opacity: 1 !important;transform: none !important; filter: none !important; color: #667eea; font-size: 2em; margin-bottom: 30px; border-bottom: 3px solid #667eea; padding-bottom: 10px; }
        .tab i { margin-right: 6px }
        /* 3D Viewer Styles */
        .viewer-box { background: #1a1a2e; border-radius: 15px; padding: 30px; margin-bottom: 30px; }
        canvas { width: 100%; height: 500px; background: #0f0f1e; border-radius: 10px; border: 3px solid #667eea; display: block; cursor: grab; }
        canvas:active { cursor: grabbing; }
        .mol-btns {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 15px;
            margin-bottom: 20px;
        }
        .mol-btn {
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            border: none;
            padding: 15px;
            border-radius: 10px;
            cursor: pointer;
            font-size: 1em;
            font-weight: bold;
            transition: all 0.3s;
        }
        .mol-btn:hover {
            background: linear-gradient(135deg, #ff7b7b 0%, #ffb43b 100%);
            transform: translateY(-4px) scale(1.04);
            box-shadow: 0 12px 30px rgba(255, 107, 107, 0.5);

            filter: brightness(1.15);
        }

        .mol-btn.active {
            background: linear-gradient(135deg, #ff3b3b 0%, #ff7b7b 100%);
            box-shadow: 0 10px 25px rgba(255, 59, 59, 0.6);
            transform: scale(1.05);
        }

        .controls {
            background: rgba(255, 255, 255, 0.1);
            padding: 20px;
            border-radius: 10px;
            color: white;
            margin-top: 20px;
        }
        .ctrl-row {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 20px;
            margin-top: 15px;
        }
        .ctrl-group label { display: block; margin-bottom: 8px; font-weight: bold; }
        input[type="range"] { width: 100%; }
        .info-box {
            background: #f8f9fa;
            padding: 25px;
            border-radius: 15px;
            margin-top: 30px;
            border: 3px solid #667eea;
        }
        .info-box h3 { color: #667eea; margin-bottom: 15px; }
        .info-box p { margin: 8px 0; line-height: 1.6; }
        .saved {
            background: rgba(255, 255, 255, 0.1);
            padding: 20px;
            border-radius: 10px;
            color: black;
            margin-top: 20px;
        }
        .saved-item {
            background: rgba(255, 255, 255, 0.2);
            padding: 12px;
            border-radius: 8px;
            margin: 10px 0;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        .vbtn {
            background: #667eea;
            color: white;
            border: none;
            padding: 8px 15px;
            border-radius: 5px;
            cursor: pointer;
            margin-left: 5px;
            transition: all 0.3s;
        }
        .vbtn:hover { background: #5568d3; }
        .vbtn.del { background: #ff6b6b; }
        .save-input {
            display: flex;
            gap: 10px;
            margin-top: 15px;
        }
        .save-input input {
            flex: 1;
            padding: 10px;
            border-radius: 5px;
            border: 2px solid #667eea;
        }
        .placeholder { padding: 40px; text-align: center; color: #666; }
        
        .topic-card {
            background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
            border-radius: 15px;
            padding: 25px;
            margin-bottom: 20px;
            transition: all 0.3s;
            cursor: pointer;
            border-left: 5px solid #667eea;
        }
        .topic-card:hover {
            transform: translateX(10px);
            box-shadow: 0 5px 15px rgba(0,0,0,0.2);
        }
        .topic-card.expanded {
            background: linear-gradient(135deg, #e0e7ff 0%, #bfdbfe 100%);
        }
        .topic-title {
            font-size: 1.3em;
            color: #333;
            margin-bottom: 10px;
            font-weight: bold;
            display: flex;
            align-items: center;
            justify-content: space-between;
        }
        .expand-icon {
            font-size: 1.5em;
            transition: transform 0.3s;
        }
        .topic-card.expanded .expand-icon {
            transform: rotate(180deg);
        }
        .topic-description {
            color: #555;
            line-height: 1.6;
            margin-bottom: 10px;
        }
        .key-points {
            background: white;
            padding: 20px;
            border-radius: 10px;
            margin-top: 15px;
            display: none;
        }
        .topic-card.expanded .key-points {
            display: block;
            animation: slideDown 0.3s;
        }
        @keyframes slideDown {
            from { opacity: 0; max-height: 0; }
            to { opacity: 1; max-height: 1000px; }
        }
        .key-points ul {
            margin-left: 20px;
        }
        .key-points li {
            margin: 8px 0;
            color: #444;
        }
        .important-badge {
            display: inline-block;
            background: #ff6b6b;
            color: white;
            padding: 5px 15px;
            border-radius: 20px;
            font-size: 0.9em;
        }
        .diagram-box {
            background: white;
            padding: 25px;
            border-radius: 15px;
            margin: 20px 0;
            border: 3px solid #667eea;
        }
        .diagram-title {
            font-size: 1.3em;
            font-weight: bold;
            color: #667eea;
            margin-bottom: 15px;
            text-align: center;
        }
        .structure-diagram {
            display: flex;
            flex-wrap: wrap;
            gap: 20px;
            justify-content: center;
            margin: 20px 0;
        }
        .structure-card {
            background: white;
            border: 2px solid #667eea;
            border-radius: 10px;
            padding: 15px;
            text-align: center;
            min-width: 150px;
        }
        .structure-name {
            font-weight: bold;
            color: #667eea;
            margin-bottom: 10px;
        }
        .pathway-step {
            background: white;
            border: 2px solid #667eea;
            border-radius: 10px;
            padding: 15px;
            margin: 10px 0;
            position: relative;
        }
        .pathway-step::after {
            content: '↓';
            position: absolute;
            bottom: -25px;
            left: 50%;
            transform: translateX(-50%);
            font-size: 2em;
            color: #667eea;
        }
        .pathway-step:last-child::after {
            content: '';
        }
        .step-name {
            font-weight: bold;
            color: #667eea;
            margin-bottom: 5px;
        }
        .enzyme-name {
            color: #ff6b6b;
            font-style: italic;
        }
        .energy-yield {
            background: #d4edda;
            color: #155724;
            padding: 5px 10px;
            border-radius: 5px;
            display: inline-block;
            margin-top: 5px;
            font-size: 0.9em;
        }
        .disclaimer-box {
            margin-top: 20px;
            padding: 12px 16px;
            border-radius: 6px;
            background: rgba(255, 255, 255, 0.08);
            border-left: 4px solid #f4b400;
            font-size: 0.9rem;
            color: black;
        }

        .disclaimer-box p {
            margin: 6px 0;
        }

        .disclaimer-box .credit {
            font-size: 0.8rem;
            opacity: 0.85;
        }

        .disclaimer-box a {
            color: #8ab4f8;
            text-decoration: none;
        }

        .disclaimer-box a:hover {
            text-decoration: underline;
        }
        .concept-card {
            background: rgba(255,255,255,0.2);
            padding: 15px;
            border-radius: 10px;
            border-left: 4px solid white;

            /* 🔑 overflow fixes */
            overflow-wrap: break-word;
            word-break: break-word;
            hyphens: auto;

            /* 🔑 readability */
            line-height: 1.5;
            font-size: 0.95rem;

            /* 🔑 alignment */
            display: flex;
            flex-direction: column;
            justify-content: flex-start;
        }
        .concept-card.light {
        background: #ffffff;
        color: #222;
        border-left: 4px solid #667eea;
        }
        #mm_run {
            margin-top: 15px;
            padding: 12px 20px;
            border: none;
            border-radius: 8px;
            background: #667eea;
            color: white;
            font-size: 1em;
            font-weight: bold;
            cursor: pointer;
            transition: background 0.3s, transform 0.2s;
        }
        #mm_run:hover {
            background: #d35555;
            transform: translateY(-2px);
        }
        #mm_run:active {
            transform: translateY(0);
        }
        #mm_fit {
            margin-top: 15px;
            padding: 12px 20px;
            border: none;
            border-radius: 8px;
            background: #28a745;
            color: white;
            font-size: 1em;
            font-weight: bold;
            cursor: pointer;
            transition: background 0.3s, transform 0.2s;
        }
        #mm_fit:hover {
            background: #782188;
            transform: translateY(-2px);
        }
        #mm_fit:active {
            transform: translateY(0);
        }
        .physics-section { font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial; }
        .diagram-box { margin-bottom:18px; }
        .diagram-title { font-weight:700; color:#6b7bdc; margin-bottom:8px; }
        /* make the svg scale nicely in its container */
        .physics-svg { width:100%; height:auto; display:block; }
        /* small visual tune-ups for SVG text */
        .svg-text { font-size:13px; fill:#2d3748; }
        .chart-container {
        position: relative;
        width: 100%;
        height: 320px;      
        max-height: 480px;
        min-height: 220px;
        overflow: hidden;   
        }

        /* ensure canvas fills the container exactly and doesn't produce extra margins */
        #mm_chart {
        display: block;
        width: 100% !important;
        height: 100% !important;
        }

        /* Footer styles */
        .site-footer{
        background: linear-gradient(180deg, #0f1724 0%, #002e89 100%);
        color: #e6eefc;
        padding: 18px 20px;
        border-radius: 1em;
        border-top: 1px solid rgba(255,255,255,0.04);
        margin-top: 28px;
        font-size: 0.95rem;
        }

        .footer-inner{
        max-width: 1100px;
        margin: 0 auto;
        display: flex;
        gap: 18px;
        align-items: center;
        justify-content: space-between;
        flex-wrap: wrap;
        padding: 6px 4px;
        }

        .footer-brand .footer-logo{
        color: inherit;
        text-decoration: none;
        font-weight: 700;
        display: inline-block;
        margin-bottom: 2px;
        }

        .footer-brand .footer-credit{
        margin: 0;
        font-size: 0.9rem;
        color: rgba(230,238,252,0.85);
        }

        .footer-nav{
        display: flex;
        gap: 12px;
        align-items: center;
        }

        .footer-nav a{
        color: rgba(230,238,252,0.95);
        text-decoration: none;
        padding: 6px 8px;
        border-radius: 6px;
        transition: background .15s ease, color .15s ease;
        font-size: 0.95rem;
        }
        .footer-nav a:hover,
        .footer-nav a:focus{
        background: rgba(255,255,255,0.04);
        outline: none;
        color: #fff;
        }

        .footer-meta{
        font-size: 0.9rem;
        color: rgba(230,238,252,0.85);
        }

        /* responsive */
        @media (max-width: 640px){
        .footer-inner{ flex-direction: column; align-items: flex-start; gap: 10px; }
        .footer-nav{ order: 3; width: 100%; }
        .footer-meta{ order: 2; }
        }