:root {
      color-scheme: dark;
      --bg: #05060d; --panel: #0a0e1d; --panel2: rgba(14,18,34,.6);
      --line: #1d2546; --line2: #2c3358;
      --text: #dfe6f5; --muted: #9fb0d8; --dim: #7e8bb0;
      --accent: #b79bff; --accent2: #7fd0ff; --link: #8fb3ff;
      --nav-w: 280px;
    }
    * { box-sizing: border-box; }
    html { scroll-behavior: smooth; }
    body { margin: 0; padding: 0; background: var(--bg); color: var(--text);
      font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Apple SD Gothic Neo", sans-serif; line-height: 1.7; }
    a { color: var(--link); text-decoration: none; }
    a:hover { text-decoration: underline; }
    body::before { content: ""; position: fixed; inset: 0; z-index: -1;
      background:
        radial-gradient(1200px 700px at 80% -10%, rgba(60,40,120,.30), transparent 60%),
        radial-gradient(900px 600px at 0% 5%, rgba(20,60,120,.25), transparent 60%),
        var(--bg); }

    /* ---- Top bar ---- */
    header.top { position: sticky; top: 0; z-index: 30; display: flex; align-items: center; gap: 14px;
      padding: 12px 20px; background: rgba(5,6,13,.82); backdrop-filter: blur(10px);
      border-bottom: 1px solid var(--line); }
    header.top .brand { font-weight: 800; font-size: 18px; letter-spacing: .5px; }
    header.top .brand .em { color: var(--accent); }
    header.top .spacer { flex: 1; }
    header.top a.play { background: linear-gradient(120deg, #5a32d8, #2a6cff); color: #fff; font-weight: 700;
      font-size: 14px; padding: 8px 18px; border-radius: 10px; }
    header.top a.play:hover { text-decoration: none; transform: translateY(-1px); }
    header.top a.home { color: var(--muted); font-size: 14px; }
    .menubtn { display: none; background: #121730; color: var(--text); border: 1px solid var(--line2);
      border-radius: 8px; padding: 7px 11px; font-size: 16px; cursor: pointer; }

    /* ---- Layout ---- */
    .layout { display: grid; grid-template-columns: var(--nav-w) minmax(0,1fr); max-width: 1280px; margin: 0 auto; }

    /* ---- Left nav (GitBook style) ---- */
    nav.side { position: sticky; top: 57px; align-self: start; height: calc(100vh - 57px); overflow-y: auto;
      padding: 22px 14px 60px 20px; border-right: 1px solid var(--line); }
    nav.side .group { margin: 0 0 6px; }
    nav.side .group > .glabel { font-size: 11px; text-transform: uppercase; letter-spacing: .12em;
      color: var(--dim); margin: 16px 8px 6px; }
    nav.side a { display: block; padding: 6px 10px; border-radius: 8px; color: var(--muted); font-size: 14px;
      border-left: 2px solid transparent; }
    nav.side a:hover { background: rgba(120,140,220,.08); text-decoration: none; color: var(--text); }
    nav.side a.active { color: #fff; background: rgba(90,60,216,.18); border-left-color: var(--accent); }
    nav.side a.sub { padding-left: 22px; font-size: 13px; color: var(--dim); }
    nav.side a.sub.active { color: #fff; }

    /* ---- Content ---- */
    main { padding: 30px 46px 120px; min-width: 0; }
    main section { scroll-margin-top: 72px; padding-top: 14px; }
    main h1 { font-size: clamp(30px, 4.5vw, 44px); margin: 6px 0 8px; letter-spacing: -.5px;
      background: linear-gradient(120deg, #fff, var(--accent) 60%, var(--accent2)); -webkit-background-clip: text;
      background-clip: text; color: transparent; }
    main .lede { font-size: 17px; color: var(--muted); max-width: 760px; }
    main h2 { font-size: 26px; margin: 8px 0 10px; padding-top: 8px; color: #eef2ff; border-bottom: 1px solid var(--line);
      padding-bottom: 8px; }
    main h3 { font-size: 18px; margin: 24px 0 8px; color: #eaf0ff; }
    main h4 { font-size: 15px; margin: 18px 0 4px; color: var(--accent2); }
    main p { margin: 10px 0; color: #cdd6ef; }
    main ul, main ol { margin: 10px 0; padding-left: 22px; color: #cdd6ef; }
    main li { margin: 5px 0; }
    main strong { color: #fff; }
    main code { background: #11162b; border: 1px solid var(--line); border-radius: 5px; padding: 1px 6px;
      font: 13px ui-monospace, Menlo, monospace; color: #b9e6ff; }
    a.urlcode { text-decoration: none; }
    a.urlcode code { color: #8fb6ff; border-color: #38427a; transition: color .12s, border-color .12s, background .12s; }
    a.urlcode:hover code { color: #cfe0ff; border-color: #8fb6ff; background: #161d3a; }
    .kbd { display: inline-block; min-width: 22px; text-align: center; background: #1a2143; border: 1px solid #38427a;
      border-bottom-width: 2px; border-radius: 6px; padding: 2px 8px; font: 12px ui-monospace, Menlo, monospace;
      color: #eaf0ff; }
    .note { border: 1px solid var(--line); border-left: 3px solid var(--accent2); border-radius: 8px;
      background: var(--panel2); padding: 12px 16px; margin: 16px 0; font-size: 14px; color: #c4cfee; }
    .note.warn { border-left-color: #ff9d5a; }
    .note .t { font-weight: 700; color: #fff; }
    .cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px,1fr)); gap: 12px; margin: 16px 0; }
    .card { border: 1px solid var(--line); border-radius: 12px; padding: 14px 16px; background: var(--panel2); }
    .card h4 { margin: 0 0 6px; color: #eaf0ff; }
    .card p { margin: 0; font-size: 13.5px; color: var(--muted); }
    figure { margin: 18px 0; border: 1px solid var(--line); border-radius: 12px; overflow: hidden; background: var(--panel); }
    figure img { display: block; width: 100%; height: auto; }
    figure figcaption { font-size: 13px; color: var(--muted); padding: 8px 14px; }
    figcaption .flyto, main p > .flyto { display: inline-block; margin-top: 8px; font-size: 13px; color: #8fb6ff;
      text-decoration: none; border: 1px solid var(--line2); border-radius: 999px; padding: 6px 14px; white-space: nowrap; }
    figcaption .flyto:hover, main p > .flyto:hover { color: #fff; background: rgba(58,93,160,.25); border-color: #8fb6ff; }
    #research-applied h3 .pill { margin-left: 8px; vertical-align: middle; font-size: 11.5px; padding: 2px 10px; }
    .shotgrid { display: grid; grid-template-columns: repeat(2,1fr); gap: 14px; }
    table { width: 100%; border-collapse: collapse; margin: 16px 0; font-size: 14px; }
    th, td { text-align: left; padding: 9px 12px; border-bottom: 1px solid var(--line); vertical-align: top; }
    th { color: #eaf0ff; font-weight: 700; background: rgba(120,140,220,.06); }
    td { color: var(--muted); }
    td strong { color: var(--text); }
    .tag { display: inline-block; font-size: 11px; padding: 1px 8px; border-radius: 999px; border: 1px solid var(--line2);
      color: var(--accent2); background: rgba(20,40,80,.4); margin-left: 6px; }
    .pill-row { display: flex; flex-wrap: wrap; gap: 8px; margin: 12px 0; }
    .pill { border: 1px solid var(--line2); border-radius: 999px; padding: 4px 12px; font-size: 13px; color: #cdd7f3;
      background: rgba(18,23,48,.6); }
    .pill b { color: var(--accent2); font-weight: 700; }
    hr.s { border: 0; border-top: 1px solid var(--line); margin: 40px 0; }
    .toptip { font-size: 13px; color: var(--dim); }
    footer.foot { text-align: center; padding: 30px 20px 50px; color: var(--dim); font-size: 13px;
      border-top: 1px solid var(--line); }

    /* ---- prev/next pager (sequential page navigation) ---- */
    nav.pager { display: flex; gap: 14px; margin: 52px 0 8px; }
    nav.pager a { display: flex; flex-direction: column; gap: 4px; max-width: 49%;
      padding: 14px 18px; border: 1px solid var(--line2); border-radius: 12px;
      background: var(--panel2); transition: border-color .15s ease, transform .15s ease; }
    nav.pager a:hover { text-decoration: none; border-color: var(--accent); transform: translateY(-1px); }
    nav.pager a.pager-prev { margin-right: auto; }
    nav.pager a.pager-next { margin-left: auto; text-align: right; align-items: flex-end; }
    nav.pager .pager-dir { font-size: 12px; color: var(--dim); }
    nav.pager .pager-title { font-size: 16px; font-weight: 700; color: var(--text); }
    @media (max-width: 720px) {
      nav.pager { flex-direction: column; }
      nav.pager a { max-width: none; }
      nav.pager a.pager-prev { margin-right: 0; }
      nav.pager a.pager-next { margin-left: 0; text-align: left; align-items: flex-start; }
    }

    /* monitor diagram — 좌3·우3 두 컬럼 (게임과 동일) */
    .cockpit-diagram { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin: 16px 0; }
    .cockpit-diagram .col-h { font-weight: 700; color: var(--accent2); font-size: 13px; text-align: center;
      padding: 6px 4px; border-bottom: 1px solid var(--line2); }
    .cockpit-diagram .mon { border: 1px solid var(--line2); border-radius: 10px; padding: 12px; background: rgba(10,16,34,.7);
      min-height: 96px; }
    .cockpit-diagram .mon .h { font-weight: 700; color: #eaf0ff; font-size: 14px; }
    .cockpit-diagram .mon .r { font-size: 12px; color: var(--accent2); margin: 2px 0 6px; }
    .cockpit-diagram .mon p { font-size: 12.5px; color: var(--muted); margin: 0; }
    .cockpit-diagram .helm { border-color: #4a3a86; background: rgba(30,22,60,.5); }
    @media (max-width: 560px) { .cockpit-diagram { grid-template-columns: 1fr; } }

    .backtop { position: fixed; right: 18px; bottom: 18px; z-index: 40; background: #1a2143; border: 1px solid #38427a;
      color: #eaf0ff; border-radius: 999px; width: 44px; height: 44px; font-size: 18px; cursor: pointer; display: none; }
    .backtop.show { display: block; }

    /* ---- Gallery ---- */
    .gallery { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 14px; margin: 18px 0; }
    .gallery figure { margin: 0; border: 1px solid var(--line); border-radius: 12px; overflow: hidden; background: var(--panel);
      cursor: zoom-in; position: relative; transition: transform .14s, box-shadow .14s, border-color .14s; }
    .gallery figure:hover { transform: translateY(-3px); border-color: #34407a; box-shadow: 0 12px 30px rgba(0,0,0,.45); }
    .gallery figure img { display: block; width: 100%; aspect-ratio: 16 / 10; object-fit: cover; background: #05060d; }
    .gallery figcaption { padding: 9px 12px; }
    .gallery figcaption b { display: block; font-size: 14px; color: #eaf0ff; }
    .gallery figcaption span { font-size: 12.5px; color: var(--muted); }
    /* "이 곳으로 비행 →" on each gallery thumbnail (showcase-deeplink.md). Navigates instead of
       opening the lightbox; sits below the caption text. */
    .gallery figcaption .flyto { display: inline-block; margin-top: 7px; font-size: 12px; color: #8fb6ff;
      text-decoration: none; border-bottom: 1px dashed #3a5da0; padding-bottom: 1px; position: relative; z-index: 1; }
    .gallery figcaption .flyto:hover { color: #cfe0ff; border-bottom-color: #8fb6ff; }
    /* Inline "비행/순항/조준 →" links inside the destination-list chapters (lists & the star table). */
    #places ul .flyto, #places table .flyto { color: #8fb6ff; text-decoration: none; white-space: nowrap;
      border-bottom: 1px dashed #3a5da0; font-size: .92em; }
    #places ul .flyto { margin-left: 4px; }
    #places ul .flyto:hover, #places table .flyto:hover { color: #cfe0ff; border-bottom-color: #8fb6ff; }
    #places table td .flyto { font-weight: 600; }
    .gallery .badge { position: absolute; top: 8px; left: 8px; font-size: 11px; padding: 2px 9px; border-radius: 999px;
      background: rgba(8,12,22,.78); border: 1px solid var(--line2); color: var(--accent2); backdrop-filter: blur(4px); }
    /* Lightbox */
    .lbox { position: fixed; inset: 0; z-index: 60; background: rgba(3,4,10,.92); backdrop-filter: blur(6px);
      display: none; align-items: center; justify-content: center; padding: 28px; cursor: zoom-out; }
    .lbox.open { display: flex; }
    .lbox figure { margin: 0; max-width: 1100px; max-height: 92vh; display: flex; flex-direction: column; cursor: default; }
    .lbox img { max-width: 100%; max-height: 82vh; object-fit: contain; border-radius: 10px; border: 1px solid var(--line); }
    .lbox figcaption { text-align: center; padding: 12px 6px 0; }
    .lbox figcaption b { display: block; font-size: 17px; color: #fff; }
    .lbox figcaption span { font-size: 14px; color: var(--muted); }
    /* "이 곳으로 비행 →": deep-link into the app with the autopilot pre-aimed (showcase-deeplink.md). */
    .lbox figcaption .flyto { display: inline-block; margin-top: 10px; font-size: 14px; color: #8fb6ff;
      text-decoration: none; border: 1px solid #3a5da0; border-radius: 8px; padding: 6px 14px; }
    .lbox figcaption .flyto:hover { color: #fff; background: rgba(58,93,160,.25); border-color: #8fb6ff; }
    .lbox .x { position: fixed; top: 16px; right: 20px; width: 42px; height: 42px; border-radius: 999px; cursor: pointer;
      background: #1a2143; border: 1px solid #38427a; color: #eaf0ff; font-size: 20px; line-height: 40px; text-align: center; }
    .lbox .nav { position: fixed; top: 50%; transform: translateY(-50%); width: 46px; height: 70px; cursor: pointer;
      background: rgba(26,33,67,.7); border: 1px solid #38427a; color: #eaf0ff; font-size: 24px; border-radius: 10px; }
    .lbox .nav.prev { left: 14px; } .lbox .nav.next { right: 14px; }
    @media (max-width: 640px) { .lbox .nav { display: none; } }

    @media (max-width: 900px) {
      .layout { grid-template-columns: 1fr; }
      nav.side { position: fixed; top: 57px; left: 0; width: 84%; max-width: 320px; z-index: 25;
        background: #070a16; transform: translateX(-105%); transition: transform .22s ease;
        height: calc(100dvh - 57px); overflow-y: auto; -webkit-overflow-scrolling: touch;
        overscroll-behavior: contain; }
      body.nav-open nav.side { transform: translateX(0); box-shadow: 0 0 50px rgba(0,0,0,.6); }
      .menubtn { display: inline-block; }
      main { padding: 24px 18px 100px; }
      .shotgrid { grid-template-columns: 1fr; }
      .cockpit-diagram { grid-template-columns: 1fr; }
      .scrim { position: fixed; inset: 57px 0 0; background: rgba(0,0,0,.5); z-index: 20; display: none; }
      body.nav-open .scrim { display: block; }
    }