:root {
        --bt-bg: #090b10;
        --bt-panel: rgba(13,16,23,.88);
        --bt-panel-soft: rgba(255,255,255,.055);
        --bt-line: rgba(255,255,255,.12);
        --bt-line-strong: rgba(255,255,255,.18);
        --bt-text: #f7fbff;
        --bt-muted: #aeb9c8;
        --bt-cyan: #35e0d1;
        --bt-orange: #ff6a00;
        --bt-orange-2: #ff7a12;
        --bt-radius: 8px;
        --bt-shadow: 0 24px 70px rgba(0,0,0,.34);
    }

    * {
        box-sizing: border-box;
    }

    html {
        min-height: 100%;
        scroll-behavior: smooth;
        background: var(--bt-bg);
    }

    body {
        margin: 0;
        min-height: 100vh;
        min-height: 100dvh;
        font-family: Inter, Arial, sans-serif;
        color: var(--bt-text);
        background:
            radial-gradient(circle at 14% 0, rgba(53,224,209,.18), transparent 32%),
            radial-gradient(circle at 86% 16%, rgba(255,106,0,.14), transparent 30%),
            linear-gradient(180deg, #0d1017 0%, #090b10 54%, #0c1018 100%);
        overflow-x: hidden;
    }

    .topbar {
        display: none;
    }

    .page {
        width: min(1440px, calc(100% - 48px));
        margin: 0 auto;
        padding: 28px 0 60px;
    }

    .layout {
        display: grid;
        grid-template-columns: 286px minmax(0, 1fr);
        gap: 18px;
        align-items: start;
    }

    .steps-nav,
    .content {
        border: 1px solid var(--bt-line);
        border-radius: var(--bt-radius);
        background:
            linear-gradient(145deg, rgba(255,255,255,.09), rgba(255,255,255,.035)),
            var(--bt-panel);
        box-shadow: inset 0 1px 0 rgba(255,255,255,.07), var(--bt-shadow);
        backdrop-filter: blur(18px);
    }

    .steps-nav {
        position: sticky;
        top: 24px;
        align-self: start;
        max-height: calc(100vh - 48px);
        padding: 16px;
        overflow: auto;
        scrollbar-width: thin;
        scrollbar-color: rgba(53,224,209,.45) rgba(255,255,255,.06);
    }

    .steps-nav::-webkit-scrollbar {
        width: 8px;
        height: 8px;
    }

    .steps-nav::-webkit-scrollbar-thumb {
        border-radius: 999px;
        background: rgba(53,224,209,.42);
    }

    .steps-nav h3 {
        margin: 4px 0 14px;
        color: var(--bt-text);
        font-size: 18px;
        line-height: 1.25;
    }

    .steps-nav section + section {
        margin-top: 20px;
        padding-top: 16px;
        border-top: 1px solid rgba(255,255,255,.10);
    }

    .steps-nav a {
        display: block;
        padding: 10px 10px;
        border-left: 2px solid rgba(255,255,255,.10);
        border-radius: 0 8px 8px 0;
        color: var(--bt-muted);
        text-decoration: none;
        font-size: 13px;
        line-height: 1.35;
        transition: background .18s ease, border-color .18s ease, color .18s ease;
    }

    .steps-nav a:hover,
    .steps-nav a.active {
        border-left-color: var(--bt-orange);
        background: linear-gradient(90deg, rgba(255,106,0,.16), rgba(53,224,209,.06));
        color: #fff;
    }

    .content {
        min-width: 0;
        padding: 34px;
        line-height: 1.68;
        overflow: hidden;
    }

    .section-title {
        margin: 0 0 22px;
        color: var(--bt-text);
        font-size: 28px;
        line-height: 1.2;
        letter-spacing: 0;
    }

    .guide-intro {
        margin: 0 0 24px;
        padding: 18px 20px;
        border: 1px solid rgba(53,224,209,.24);
        border-radius: var(--bt-radius);
        background:
            radial-gradient(circle at 12% 0, rgba(53,224,209,.13), transparent 34%),
            radial-gradient(circle at 92% 100%, rgba(255,106,0,.12), transparent 36%),
            rgba(255,255,255,.055);
    }

    .guide-intro p {
        margin: 0;
    }

    .section-title.sub {
        margin-top: 48px;
        padding-top: 26px;
        border-top: 1px solid rgba(255,255,255,.10);
    }

    .step-heading {
        display: flex;
        align-items: center;
        gap: 12px;
        margin: 32px 0 14px;
    }

    .step-heading span {
        min-width: 82px;
        height: 38px;
        padding: 0 18px;
        border: 1px solid rgba(255,106,0,.42);
        border-radius: 999px;
        display: inline-flex;
        align-items: center;
        justify-content: center;
        background: linear-gradient(135deg, var(--bt-orange-2), var(--bt-orange));
        color: #fff;
        font-size: 14px;
        font-weight: 900;
        box-shadow: 0 10px 24px rgba(255,106,0,.18);
    }

    .step-heading h2 {
        margin: 0;
        color: var(--bt-text);
        font-size: 18px;
        line-height: 1.25;
    }

    .guide-step {
        margin-top: 30px;
    }

    .guide-step:first-of-type {
        margin-top: 0;
    }

    .step-copy {
        margin: 0 0 12px;
    }

    .step-note {
        margin: 12px 0 14px;
        padding: 13px 15px;
        border: 1px solid rgba(255,106,0,.28);
        border-radius: var(--bt-radius);
        background: rgba(255,106,0,.10);
    }

    .step-note p {
        margin: 0;
    }

    .step-note p + p {
        margin-top: 8px;
    }

    .step-image-card {
        margin: 14px 0 18px;
        padding: 10px;
        border: 1px solid rgba(255,255,255,.10);
        border-radius: var(--bt-radius);
        background:
            linear-gradient(145deg, rgba(255,255,255,.07), rgba(255,255,255,.025)),
            rgba(255,255,255,.04);
    }

    .method-grid {
        display: grid;
        grid-template-columns: repeat(2, minmax(0, 1fr));
        gap: 18px;
    }

    .method-card {
        min-width: 0;
        padding: 14px;
        border: 1px solid rgba(255,255,255,.10);
        border-radius: var(--bt-radius);
        display: flex;
        flex-direction: column;
        justify-content: space-between;
        background:
            linear-gradient(145deg, rgba(53,224,209,.10), rgba(255,106,0,.055)),
            rgba(255,255,255,.045);
    }

    .method-card strong {
        display: block;
        margin-bottom: 8px;
        color: var(--bt-cyan);
        font-weight: 900;
    }

    p,
    li {
        color: var(--bt-muted);
        font-size: 15px;
    }

    strong {
        color: var(--bt-text);
        font-weight: 850;
    }

    .guide-img,
    .wide-img {
        width: 100%;
        max-width: 100%;
        margin: 14px 0 18px;
        border: 1px solid rgba(255,255,255,.10);
        border-radius: var(--bt-radius);
        background: rgba(255,255,255,.06);
        box-shadow: inset 0 1px 0 rgba(255,255,255,.06), 0 14px 34px rgba(0,0,0,.24);
        cursor: pointer;
    }

    ul {
        margin-top: 8px;
        padding-left: 22px;
    }

    li {
        margin: 6px 0;
    }

    .lightbox {
        position: fixed;
        inset: 0;
        z-index: 10030;
        padding: 20px;
        display: none;
        align-items: center;
        justify-content: center;
        background: rgba(3,5,10,.78);
        backdrop-filter: blur(12px);
    }

    .lightbox.open {
        display: flex;
    }

    .lightbox img {
        max-width: min(1100px, 96vw);
        max-height: 92vh;
        border: 1px solid rgba(255,255,255,.16);
        border-radius: var(--bt-radius);
        background: #0d1017;
        box-shadow: 0 30px 90px rgba(0,0,0,.48);
    }

    .lightbox button {
        position: absolute;
        top: 18px;
        right: 18px;
        width: 42px;
        height: 42px;
        border: 1px solid rgba(255,255,255,.16);
        border-radius: 999px;
        background: rgba(13,16,23,.92);
        color: var(--bt-text);
        font-size: 24px;
        cursor: pointer;
    }