/* Справочник в виде книги: папка над статьёй (c/<статья>.html) и окно с 3D-книгой.
   Статья остаётся основным текстом страницы; книга — тот же текст на разворотах, three.js грузится только по нажатию. */

.gb-entry{max-width:820px;margin:18px 0 26px}
.gb-folder{all:unset;box-sizing:border-box;display:grid;grid-template-columns:232px 1fr;align-items:center;gap:28px;width:100%;padding:18px 26px 18px 18px;border:1px solid #E3E5E8;border-radius:18px;background:#fff;cursor:pointer;transition:border-color .25s ease, box-shadow .25s ease}
.gb-folder:hover{border-color:#C9D6EE;box-shadow:0 10px 30px -18px rgba(11,71,168,.35)}
.gb-folder:focus-visible{outline:2px solid #0b47a8;outline-offset:3px}

/* Папка: задняя стенка с ярлыком, два листа, передняя крышка откидывается к зрителю */
.gb-folder__art{position:relative;display:block;height:150px;border-radius:12px;background:#F5F6F7;perspective:700px;overflow:hidden}
.gb-folder__back,.gb-folder__front,.gb-folder__sheet{position:absolute;left:34px;right:34px;display:block}
.gb-folder__back{top:26px;bottom:18px;border-radius:4px 6px 4px 4px;background:#093d93}
.gb-folder__back::before{content:"";position:absolute;left:0;top:-10px;width:62px;height:14px;border-radius:5px 5px 0 0;background:#093d93}
.gb-folder__sheet{top:22px;bottom:22px;margin:0 9px;border-radius:2px;background:#fff;box-shadow:0 1px 2px rgba(23,25,28,.18);transition:transform .45s cubic-bezier(.2,.8,.2,1)}
.gb-folder__sheet::before{content:"";position:absolute;left:12px;right:30px;top:12px;height:46px;background:repeating-linear-gradient(#D5D8DD 0 1px,transparent 1px 8px)}
.gb-folder__sheet--2{margin:0 16px;top:30px;background:#FAFAFB}
.gb-folder__sheet--2::before{left:auto;right:12px;width:44px;height:30px;top:16px;background:none;border:1px solid #9AA3AE;border-radius:1px}
.gb-folder__front{top:44px;bottom:18px;border-radius:3px 3px 4px 4px;background:linear-gradient(180deg,#1253BD 0%,#0b47a8 60%,#0a3f96 100%);transform-origin:50% 100%;transform:rotateX(0deg);transition:transform .5s cubic-bezier(.2,.8,.2,1);box-shadow:0 -1px 0 rgba(255,255,255,.18) inset}
.gb-folder__label{position:absolute;left:12px;top:14px;display:flex;flex-direction:column;gap:3px;padding:7px 9px;border-radius:2px;background:#fff;color:#17191C;font:600 9px/1.15 'IBM Plex Sans',sans-serif;letter-spacing:.06em;text-transform:uppercase}
.gb-folder__label span{font-weight:500;letter-spacing:0;text-transform:none;font-size:10.5px;color:#2B3036}
.gb-folder__logo{position:absolute;right:10px;bottom:9px;width:28px;height:28px;padding:2px;border-radius:50%;background:#fff}
.gb-folder:hover .gb-folder__front,.gb-folder:focus-visible .gb-folder__front{transform:rotateX(-34deg)}
.gb-folder:hover .gb-folder__sheet--1,.gb-folder:focus-visible .gb-folder__sheet--1{transform:translateY(-12px)}
.gb-folder:hover .gb-folder__sheet--2,.gb-folder:focus-visible .gb-folder__sheet--2{transform:translateY(-6px) rotate(-1.5deg)}

.gb-entry__text{display:flex;flex-direction:column;gap:6px;min-width:0}
.gb-entry__kicker{font:600 12px/1.2 'IBM Plex Sans',sans-serif;letter-spacing:.08em;text-transform:uppercase;color:#0b47a8}
.gb-entry__title{font:600 21px/1.25 'IBM Plex Sans',sans-serif;color:#17191C;letter-spacing:-.01em}
.gb-entry__meta{font:400 14.5px/1.45 'IBM Plex Sans',sans-serif;color:#646A71}
.gb-entry__cta{display:inline-flex;align-items:center;gap:8px;align-self:flex-start;margin-top:8px;padding:9px 18px;border-radius:980px;background:#0b47a8;color:#fff;font:500 15px/1.2 'IBM Plex Sans',sans-serif;transition:background .2s ease}
.gb-folder:hover .gb-entry__cta{background:#093d93}
.gb-entry__cta svg{transition:transform .25s ease}
.gb-folder:hover .gb-entry__cta svg{transform:translateX(3px)}
.gb-entry[hidden]{display:none}

@media (max-width:640px){
  .gb-folder{grid-template-columns:1fr;gap:16px;padding:14px}
  .gb-folder__art{height:132px}
}
@media (prefers-reduced-motion:reduce){
  .gb-folder__front,.gb-folder__sheet,.gb-entry__cta svg{transition:none}
}

/* Окно книги */
.gb-open{overflow:hidden}
.gb-overlay{position:fixed;inset:0;z-index:2000;background:#E4E7EA;opacity:0;transition:opacity .35s ease;font-family:'IBM Plex Sans',sans-serif;color:#17191C}
.gb-overlay.is-in{opacity:1}
.gb-overlay canvas{position:absolute;inset:0;width:100%;height:100%;display:block;outline:none}
.gb-overlay.is-hover canvas{cursor:pointer}
.gb-overlay.is-grab canvas{cursor:grab}
.gb-overlay.is-grab:active canvas{cursor:grabbing}
.gb-loading{position:absolute;left:50%;top:50%;transform:translate(-50%,-50%);display:flex;align-items:center;gap:12px;font:500 15px/1 'IBM Plex Sans',sans-serif;color:#646A71;transition:opacity .3s ease}
.gb-loading::before{content:"";width:18px;height:18px;border-radius:50%;border:2px solid #C9D6EE;border-top-color:#0b47a8;animation:gb-spin .8s linear infinite}
.gb-loading.is-off{opacity:0;pointer-events:none}
@keyframes gb-spin{to{transform:rotate(360deg)}}

.gb-bar{position:absolute;left:50%;bottom:22px;transform:translateX(-50%);display:flex;align-items:center;gap:4px;padding:6px;border-radius:980px;background:rgba(255,255,255,.78);backdrop-filter:blur(18px) saturate(1.4);-webkit-backdrop-filter:blur(18px) saturate(1.4);box-shadow:0 1px 0 rgba(255,255,255,.7) inset,0 10px 30px -12px rgba(23,25,28,.28);border:1px solid rgba(23,25,28,.06)}
.gb-btn{all:unset;box-sizing:border-box;display:inline-flex;align-items:center;justify-content:center;gap:8px;min-width:40px;height:40px;padding:0 10px;border-radius:980px;color:#2B3036;cursor:pointer;font:500 14px/1 'IBM Plex Sans',sans-serif;transition:background .2s ease,color .2s ease,transform .15s ease}
.gb-btn:hover{background:rgba(11,71,168,.08);color:#0b47a8}
.gb-btn:active{transform:scale(.94)}
.gb-btn:focus-visible{outline:2px solid #0b47a8;outline-offset:1px}
.gb-btn[disabled]{opacity:.32;pointer-events:none}
.gb-btn svg{width:20px;height:20px;flex:none}
.gb-title{min-width:230px;padding:0 8px;text-align:center;font:500 14px/1.2 'IBM Plex Sans',sans-serif;color:#17191C;white-space:nowrap}
.gb-title small{display:block;margin-top:3px;font-size:12px;font-weight:400;color:#646A71}
.gb-sep{width:1px;height:22px;margin:0 4px;background:rgba(23,25,28,.1)}

.gb-toc{position:absolute;left:50%;bottom:84px;transform:translate(-50%,8px);min-width:340px;padding:8px;border-radius:18px;background:rgba(255,255,255,.92);backdrop-filter:blur(18px);-webkit-backdrop-filter:blur(18px);box-shadow:0 18px 40px -16px rgba(23,25,28,.3);border:1px solid rgba(23,25,28,.06);opacity:0;pointer-events:none;transition:opacity .2s ease,transform .2s ease}
.gb-toc.is-open{opacity:1;transform:translate(-50%,0);pointer-events:auto}
.gb-toc button{all:unset;box-sizing:border-box;display:flex;align-items:baseline;gap:12px;width:100%;padding:10px 12px;border-radius:12px;cursor:pointer;font:400 15px/1.3 'IBM Plex Sans',sans-serif;color:#2B3036}
.gb-toc button:hover,.gb-toc button:focus-visible{background:#EEF2F9;color:#0b47a8}
.gb-toc button[aria-current="true"]{font-weight:600;color:#0b47a8}
.gb-toc b{width:20px;flex:none;font:500 13px/1.3 'IBM Plex Mono',monospace;color:#8A9097}

.gb-close{position:absolute;right:20px;top:18px}
.gb-close.gb-btn{background:rgba(255,255,255,.78);backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px);border:1px solid rgba(23,25,28,.06);padding:0 16px 0 12px}

/* Подписи к деталям чертежа: позиционируются из 3D-сцены */
.gb-tags{position:absolute;inset:0;pointer-events:none}
.gb-tag{position:absolute;left:0;top:0;padding:6px 10px;border-radius:8px;background:#fff;color:#17191C;font:500 13px/1.25 'IBM Plex Sans',sans-serif;white-space:nowrap;box-shadow:0 6px 18px -8px rgba(23,25,28,.35);border:1px solid #E3E5E8;opacity:0;transform:translate(-50%,calc(-100% - 10px)) scale(.96);transition:opacity .18s ease,transform .18s ease}
.gb-tag::after{content:"";position:absolute;left:50%;bottom:-5px;width:8px;height:8px;margin-left:-4px;background:#fff;border-right:1px solid #E3E5E8;border-bottom:1px solid #E3E5E8;transform:rotate(45deg)}
.gb-tag.is-on{opacity:1;transform:translate(-50%,calc(-100% - 10px)) scale(1)}
.gb-tag.is-found{background:#0b47a8;color:#fff;border-color:#0b47a8}
.gb-tag.is-found::after{background:#0b47a8;border-color:#0b47a8}

.gb-flash{position:absolute;inset:0;background:#fff;opacity:0;pointer-events:none}
.gb-flash.is-on{animation:gb-flash .45s ease-out}
@keyframes gb-flash{0%{opacity:.85}100%{opacity:0}}

.gb-hint{position:absolute;left:50%;top:22px;transform:translateX(-50%);padding:8px 14px;border-radius:980px;background:rgba(255,255,255,.78);backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px);font:400 13.5px/1.2 'IBM Plex Sans',sans-serif;color:#2B3036;border:1px solid rgba(23,25,28,.06);transition:opacity .4s ease;white-space:nowrap}
.gb-hint.is-off{opacity:0;visibility:hidden}
.gb-sr{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}

@media (max-width:767px){
  .gb-title{min-width:0;max-width:44vw;overflow:hidden;text-overflow:ellipsis}
  .gb-title small{display:none}
  .gb-bar{bottom:12px}
  .gb-hint{display:none}
  .gb-toc{min-width:0;width:calc(100vw - 32px)}
}