:root {
            --blue: #2490e3;
            --blue-light: #e8f4fd;
            --blue-mid: #b3d9f7;
            --green: #22c55e;
            --red: #ef4444;
            --orange: #f97316;
            --purple: #8b5cf6;
            --text: #1e293b;
            --muted: #64748b;
            --border: #e2e8f0;
            --card: #f8fafc;
        }

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

        html {
            scroll-behavior: smooth;
        }

        body {
            font-family: "Plus Jakarta Sans", sans-serif;
            background: #fff;
            color: var(--text);
            font-size: 15px;
            line-height: 1.7;
            overflow-x: hidden;
        }

        /* Progress */
        #bar {
            position: fixed;
            top: 0;
            left: 0;
            height: 3px;
            background: linear-gradient(90deg, var(--blue), #60c8ff);
            width: 0;
            z-index: 9999;
            transition: width 0.1s linear;
            border-radius: 0 2px 2px 0;
        }

        /* HERO */
        .hero {
            text-align: center;
            padding: 7rem 2rem 5rem;
            position: relative;
            overflow: hidden;
        }

        .hero::before {
            content: "";
            position: absolute;
            inset: 0;
            background: radial-gradient(ellipse 80% 60% at 50% 0%,
                    rgba(36, 144, 227, 0.07) 0%,
                    transparent 70%);
            pointer-events: none;
        }

        .blob {
            position: absolute;
            border-radius: 50%;
            filter: blur(55px);
            opacity: 0.4;
            pointer-events: none;
            animation: drift 9s ease-in-out infinite alternate;
        }

        .b1 {
            width: 300px;
            height: 300px;
            background: #bfdbfe;
            top: -80px;
            left: -60px;
            animation-delay: 0s;
        }

        .b2 {
            width: 200px;
            height: 200px;
            background: #c7f2d4;
            top: 30px;
            right: -40px;
            animation-delay: 2.5s;
        }

        .b3 {
            width: 160px;
            height: 160px;
            background: #fde8c8;
            bottom: 0;
            left: 35%;
            animation-delay: 5s;
        }

        @keyframes drift {
            from {
                transform: translate(0, 0) scale(1);
            }

            to {
                transform: translate(18px, 14px) scale(1.06);
            }
        }

        .hero-tag {
            display: inline-flex;
            align-items: center;
            gap: 0.4rem;
            background: var(--blue-light);
            color: var(--blue);
            font-size: 0.72rem;
            font-weight: 700;
            letter-spacing: 0.12em;
            text-transform: uppercase;
            padding: 0.4rem 1.1rem;
            border-radius: 999px;
            margin-bottom: 2rem;
            border: 1px solid var(--blue-mid);
            animation: popIn 0.5s cubic-bezier(0.34, 1.56, 0.64, 1) both;
        }

        .hero h1 {
            font-size: clamp(2.4rem, 5.5vw, 4rem);
            font-weight: 800;
            line-height: 1.08;
            letter-spacing: -0.03em;
            color: var(--text);
            margin-bottom: 1.2rem;
            animation: slideUp 0.55s 0.1s ease both;
        }

        .hero h1 .accent {
            color: var(--blue);
            position: relative;
            display: inline-block;
        }

        .hero h1 .accent::after {
            content: "";
            position: absolute;
            bottom: 2px;
            left: 0;
            right: 0;
            height: 4px;
            background: linear-gradient(90deg, var(--blue), #60c8ff);
            border-radius: 2px;
            transform-origin: left;
            animation: growLine 0.7s 0.8s ease both;
        }

        @keyframes growLine {
            from {
                transform: scaleX(0);
                opacity: 0;
            }

            to {
                transform: scaleX(1);
                opacity: 1;
            }
        }

        .hero p {
            color: var(--muted);
            font-size: 1.05rem;
            max-width: 540px;
            margin: 0 auto 2.5rem;
            animation: slideUp 0.55s 0.2s ease both;
        }

        .pills {
            display: flex;
            flex-wrap: wrap;
            gap: 0.5rem;
            justify-content: center;
            animation: slideUp 0.55s 0.3s ease both;
        }

        .pill {
            font-size: 0.75rem;
            font-weight: 600;
            padding: 0.35rem 0.9rem;
            border-radius: 999px;
            border: 1.5px solid;
        }

        .pi-b {
            color: var(--blue);
            border-color: #bfdbfe;
            background: #eff6ff;
        }

        .pi-g {
            color: var(--green);
            border-color: #bbf7d0;
            background: #f0fdf4;
        }

        .pi-r {
            color: var(--red);
            border-color: #fecaca;
            background: #fef2f2;
        }

        .pi-o {
            color: var(--orange);
            border-color: #fed7aa;
            background: #fff7ed;
        }

        .pi-p {
            color: var(--purple);
            border-color: #ddd6fe;
            background: #f5f3ff;
        }

        /* TOC */
        .toc {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(115px, 1fr));
            gap: 0.75rem;
            max-width: 820px;
            margin: 0 auto 5rem;
            padding: 0 1.5rem;
        }

        .toc-a {
            text-decoration: none;
            background: #fff;
            border: 1.5px solid var(--border);
            border-radius: 14px;
            padding: 1.1rem 0.75rem;
            text-align: center;
            transition: all 0.22s ease;
            color: var(--text);
        }

        .toc-a:hover {
            border-color: var(--blue);
            background: var(--blue-light);
            transform: translateY(-4px);
            box-shadow: 0 8px 24px rgba(36, 144, 227, 0.12);
        }

        .toc-n {
            font-size: 1.6rem;
            font-weight: 800;
            color: var(--blue);
            display: block;
            line-height: 1;
        }

        .toc-l {
            font-size: 0.67rem;
            font-weight: 600;
            letter-spacing: 0.07em;
            text-transform: uppercase;
            color: var(--muted);
            display: block;
            margin-top: 0.35rem;
        }

        /* MAIN */
        main {
            max-width: 880px;
            margin: 0 auto;
            padding: 0 1.5rem 6rem;
        }

        /* SECTION */
        .section {
            margin-bottom: 5rem;
            scroll-margin-top: 80px;
            opacity: 0;
            transform: translateY(28px);
            transition:
                opacity 0.5s ease,
                transform 0.5s ease;
        }

        .section.in {
            opacity: 1;
            transform: translateY(0);
        }

        .sec-head {
            display: flex;
            align-items: center;
            gap: 0.85rem;
            margin-bottom: 2rem;
            padding-bottom: 1rem;
            border-bottom: 2px solid var(--border);
        }

        .sec-num {
            background: var(--blue-light);
            color: var(--blue);
            font-size: 0.7rem;
            font-weight: 700;
            letter-spacing: 0.1em;
            padding: 0.3rem 0.75rem;
            border-radius: 6px;
            white-space: nowrap;
            border: 1px solid var(--blue-mid);
        }

        .sec-head h2 {
            font-size: clamp(1.3rem, 2.5vw, 1.75rem);
            font-weight: 700;
            letter-spacing: -0.02em;
        }

        /* CARD */
        .card {
            background: var(--card);
            border: 1.5px solid var(--border);
            border-radius: 14px;
            padding: 1.5rem;
            margin-bottom: 1.25rem;
        }

        .card h3 {
            font-size: 0.72rem;
            font-weight: 700;
            letter-spacing: 0.1em;
            text-transform: uppercase;
            color: var(--blue);
            margin-bottom: 1rem;
        }

        /* DUO */
        .duo {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 1rem;
            margin-bottom: 1.25rem;
        }

        @media (max-width: 600px) {
            .duo {
                grid-template-columns: 1fr;
            }
        }

        .do-c,
        .dont-c {
            border-radius: 12px;
            padding: 1.1rem;
            border: 1.5px solid;
        }

        .do-c {
            background: #f0fdf4;
            border-color: #bbf7d0;
        }

        .dont-c {
            background: #fef2f2;
            border-color: #fecaca;
        }

        .do-c h4 {
            color: var(--green);
            font-size: 0.72rem;
            font-weight: 700;
            letter-spacing: 0.08em;
            text-transform: uppercase;
            margin-bottom: 0.75rem;
        }

        .dont-c h4 {
            color: var(--red);
            font-size: 0.72rem;
            font-weight: 700;
            letter-spacing: 0.08em;
            text-transform: uppercase;
            margin-bottom: 0.75rem;
        }

        ul {
            padding-left: 1.3rem;
        }

        li {
            margin-bottom: 0.35rem;
            color: var(--muted);
            font-size: 0.88rem;
        }

        /* ALERT */
        .alert {
            display: flex;
            gap: 0.75rem;
            align-items: flex-start;
            padding: 1rem 1.2rem;
            border-radius: 10px;
            font-size: 0.88rem;
            margin-bottom: 1.25rem;
            border: 1.5px solid;
        }

        .a-info {
            background: #eff6ff;
            border-color: #bfdbfe;
            color: #1d4ed8;
        }

        .a-warn {
            background: #fef2f2;
            border-color: #fecaca;
            color: #b91c1c;
        }

        /* CODE */
        .cw {
            background: #f8fafc;
            border: 1.5px solid var(--border);
            border-radius: 12px;
            overflow: hidden;
            margin-bottom: 1.25rem;
        }

        .ct {
            background: #f1f5f9;
            padding: 0.5rem 1rem;
            font-size: 0.68rem;
            font-weight: 700;
            letter-spacing: 0.12em;
            text-transform: uppercase;
            color: var(--muted);
            border-bottom: 1.5px solid var(--border);
            display: flex;
            align-items: center;
            gap: 0.4rem;
        }

        .dot {
            width: 8px;
            height: 8px;
            border-radius: 50%;
            display: inline-block;
        }

        .dr {
            background: #f87171;
        }

        .dy {
            background: #fbbf24;
        }

        .dg {
            background: #4ade80;
        }

        pre {
            margin: 0;
            padding: 1.2rem;
            overflow-x: auto;
            font-family: "Fira Code", monospace;
            font-size: 0.82rem;
            line-height: 1.65;
            color: #334155;
        }

        .kw {
            color: #7c3aed;
            font-weight: 600;
        }

        .fn {
            color: #0369a1;
        }

        .st {
            color: #16a34a;
        }

        .cm {
            color: #94a3b8;
            font-style: italic;
        }

        .at {
            color: #b45309;
        }

        .tg {
            color: #be185d;
        }

        .cs {
            color: #0e7490;
        }

        /* TABLE */
        .tw {
            overflow-x: auto;
            margin-bottom: 1.25rem;
        }

        table {
            width: 100%;
            border-collapse: collapse;
            font-size: 0.87rem;
        }

        th {
            background: var(--card);
            color: var(--text);
            font-weight: 700;
            font-size: 0.7rem;
            letter-spacing: 0.08em;
            text-transform: uppercase;
            padding: 0.7rem 1rem;
            text-align: left;
            border-bottom: 2px solid var(--border);
        }

        td {
            padding: 0.7rem 1rem;
            border-bottom: 1px solid #f1f5f9;
            color: var(--muted);
            vertical-align: top;
        }

        tr:hover td {
            background: #f8fafc;
        }

        td:first-child {
            color: var(--text);
            font-weight: 500;
        }

        code {
            background: #eff6ff;
            color: var(--blue);
            padding: 0.12rem 0.42rem;
            border-radius: 5px;
            font-family: "Fira Code", monospace;
            font-size: 0.82em;
        }

        /* FIELD VIZ */
        .fviz {
            border: 1.5px solid var(--border);
            border-radius: 12px;
            overflow: hidden;
            font-family: "Fira Code", monospace;
            font-size: 0.82rem;
        }

        .fviz-row {
            border-bottom: 1.5px solid var(--border);
        }

        .fviz-row:last-child {
            border-bottom: none;
        }

        .fviz-lbl {
            background: #f1f5f9;
            padding: 0.55rem 1.2rem;
            font-size: 0.7rem;
            font-weight: 700;
            letter-spacing: 0.1em;
            text-transform: uppercase;
            color: var(--blue);
        }

        .fviz-body {
            padding: 1rem 1.2rem;
            color: #475569;
            line-height: 1.6;
        }

        /* METHODS */
        .mgrid {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 0.75rem;
        }

        @media (max-width: 560px) {
            .mgrid {
                grid-template-columns: 1fr;
            }
        }

        .mc {
            background: #fff;
            border: 1.5px solid var(--border);
            border-radius: 10px;
            padding: 0.9rem;
            transition:
                border-color 0.2s,
                box-shadow 0.2s;
        }

        .mc:hover {
            border-color: var(--blue);
            box-shadow: 0 4px 14px rgba(36, 144, 227, 0.1);
        }

        .mc code {
            display: block;
            margin-bottom: 0.3rem;
            font-size: 0.78rem;
        }

        .mc small {
            color: var(--muted);
            font-size: 0.78rem;
        }

        /* DETAILS */
        details {
            background: #fff;
            border: 1.5px solid var(--border);
            border-radius: 12px;
            margin-bottom: 0.75rem;
            overflow: hidden;
            transition: border-color 0.2s;
        }

        details:hover {
            border-color: var(--blue-mid);
        }

        details[open] {
            border-color: var(--blue);
        }

        summary {
            padding: 1rem 1.2rem;
            cursor: pointer;
            font-weight: 600;
            font-size: 0.93rem;
            list-style: none;
            display: flex;
            align-items: center;
            gap: 0.5rem;
            user-select: none;
            transition: background 0.3s ease, padding-left 0.28s ease;
            position: relative;
        }

        summary:hover {
            background: var(--blue-light);
            padding-left: 1.4rem;
        }

        summary::before {
            content: '';
            position: absolute;
            left: 0;
            top: 50%;
            transform: translateY(-50%);
            width: 3px;
            height: 0;
            background: var(--blue);
            transition: height 0.3s ease;
        }

        summary:hover::before {
            height: 60%;
        }

        summary::-webkit-details-marker {
            display: none;
        }

        summary::after {
            content: "+";
            margin-left: auto;
            color: var(--blue);
            font-size: 1.3rem;
            font-weight: 700;
            transition: transform 0.32s ease, opacity 0.2s ease;
            transform-origin: center;
        }

        details[open] summary::after {
            content: "−";
            transform: rotate(180deg);
        }

        /* A wrapping element for details content to enable smooth replayable transitions */
        .details-body {
            padding: 0 1.2rem 1.2rem;
            overflow: hidden;
            max-height: 0;
            opacity: 0;
            transition: max-height 0.36s cubic-bezier(.2,.9,.2,1), opacity 0.28s ease;
            will-change: max-height, opacity;
        }

        /* Replayable open animation */
        .details-body.replay {
            animation: slideDown 0.34s ease-out;
        }

        @keyframes slideDown {
            from {
                opacity: 0;
                transform: translateY(-8px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        details summary {
            transition: all 0.3s ease;
        }

        details[open] summary {
            background: var(--blue-light);
        }

        @media (prefers-reduced-motion: reduce) {
            .details-body,
            .details-body.replay,
            summary,
            summary::after {
                animation: none !important;
                transition: none !important;
            }
        }

        /* DEVELOPER */
        .dev {
            background: linear-gradient(135deg, #eff6ff 0%, #f0fdf4 100%);
            border: 1.5px solid var(--blue-mid);
            border-radius: 20px;
            padding: 3rem 2rem;
            text-align: center;
            margin-bottom: 3rem;
            position: relative;
            overflow: hidden;
        }

        .dev::before {
            content: "";
            position: absolute;
            top: -60px;
            right: -60px;
            width: 200px;
            height: 200px;
            background: radial-gradient(circle,
                    rgba(36, 144, 227, 0.12),
                    transparent 70%);
            border-radius: 50%;
        }

        .dev-av {
            width: 76px;
            height: 76px;
            border-radius: 50%;
            background: linear-gradient(135deg, var(--blue), #60c8ff);
            color: #fff;
            font-weight: 800;
            font-size: 1.7rem;
            display: flex;
            align-items: center;
            justify-content: center;
            margin: 0 auto 1.25rem;
            box-shadow: 0 8px 24px rgba(36, 144, 227, 0.3);
            animation: pulse 3s ease-in-out infinite;
        }

        @keyframes pulse {

            0%,
            100% {
                box-shadow: 0 8px 24px rgba(36, 144, 227, 0.3);
            }

            50% {
                box-shadow: 0 8px 36px rgba(36, 144, 227, 0.55);
            }
        }

        .dev-name {
            font-size: 1.6rem;
            font-weight: 800;
            letter-spacing: -0.02em;
            margin-bottom: 0.25rem;
        }

        .dev-role {
            color: var(--muted);
            font-size: 0.88rem;
            margin-bottom: 2rem;
        }

        .clinks {
            display: flex;
            flex-wrap: wrap;
            gap: 0.6rem;
            justify-content: center;
        }

        .cl {
            display: inline-flex;
            align-items: center;
            gap: 0.45rem;
            padding: 0.5rem 1.1rem;
            border-radius: 10px;
            text-decoration: none;
            font-size: 0.8rem;
            font-weight: 600;
            border: 1.5px solid;
            transition: all 0.2s;
            background: #fff;
        }

        .cl:hover {
            transform: translateY(-2px);
            box-shadow: 0 6px 18px rgba(0, 0, 0, 0.1);
        }

        .cl-ph {
            color: var(--green);
            border-color: #bbf7d0;
        }

        .cl-wa {
            color: #16a34a;
            border-color: #86efac;
        }

        .cl-fb {
            color: #1d4ed8;
            border-color: #bfdbfe;
        }

        .cl-gh {
            color: #0f172a;
            border-color: #cbd5e1;
        }

        .cl-li {
            color: #0369a1;
            border-color: #bae6fd;
        }

        /* FOOTER */
        .foot {
            text-align: center;
            padding: 2rem;
            border-top: 1.5px solid var(--border);
            color: var(--muted);
            font-size: 0.82rem;
        }

        .foot a {
            color: var(--blue);
            text-decoration: none;
        }

        hr {
            border: none;
            border-top: 1.5px solid var(--border);
            margin: 3rem 0;
        }

        /* ANIMATIONS */
        @keyframes popIn {
            from {
                opacity: 0;
                transform: scale(0.85);
            }

            to {
                opacity: 1;
                transform: scale(1);
            }
        }

        @keyframes slideUp {
            from {
                opacity: 0;
                transform: translateY(20px);
            }

            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        @keyframes float {
            0%, 100% { transform: translateY(0px); }
            50% { transform: translateY(-10px); }
        }

        @keyframes rotate {
            from { transform: rotate(0deg); }
            to { transform: rotate(360deg); }
        }

        @keyframes bounce {
            0%, 100% { transform: translateY(0); }
            50% { transform: translateY(-5px); }
        }

        .icon-animate {
            display: inline-block;
            animation: float 3s ease-in-out infinite;
        }

        .icon-spin {
            display: inline-block;
            animation: rotate 20s linear infinite;
        }

        .icon-bounce {
            display: inline-block;
            animation: bounce 2s ease-in-out infinite;
        }

        .lang-icon {
            font-size: 1.2em;
            vertical-align: middle;
            margin-right: 0.3rem;
        }