/* ─── FLIPBOOK ─────────────────────────────── */
#fb-overlay{display:none;position:fixed;inset:0;z-index:99999;background:rgba(0,0,0,.88);align-items:center;justify-content:center;flex-direction:column;}
#fb-overlay.fb-open{display:flex;}
#fb-ui{display:flex;flex-direction:column;align-items:center;gap:12px;width:100%;max-height:100vh;padding:14px 10px;box-sizing:border-box;}
#fb-header{display:flex;align-items:center;gap:14px;color:rgba(255,255,255,.9);font-family:Verdana,sans-serif;font-size:12px;width:100%;max-width:920px;}
#fb-doc-title{flex:1;font-weight:bold;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;}
#fb-ctr{color:rgba(255,255,255,.55);font-size:11px;white-space:nowrap;}
#fb-x{background:none;border:1px solid rgba(255,255,255,.3);color:rgba(255,255,255,.8);font-size:16px;cursor:pointer;padding:2px 10px;border-radius:3px;transition:background .2s;}
#fb-x:hover{background:rgba(255,255,255,.15);}
#fb-stage{display:flex;align-items:center;gap:8px;flex:1;width:100%;max-width:920px;}
#fb-book{display:flex;flex:1;max-height:calc(100vh - 110px);box-shadow:0 20px 60px rgba(0,0,0,.8);border-radius:2px;overflow:hidden;perspective:2000px;perspective-origin:50% 50%;}
#fb-lp,#fb-rp{flex:1;background:#1a1a1a;display:flex;align-items:center;justify-content:center;overflow:hidden;}
#fb-lp{border-right:3px solid #000;transform-origin:right center;}
#fb-rp{transform-origin:left center;}
#fb-lp img,#fb-rp img{width:100%;height:100%;object-fit:contain;display:block;}
#fb-rp{position:relative;}
.fb-fold{position:absolute;inset:0;transform-origin:left center;backface-visibility:hidden;-webkit-backface-visibility:hidden;display:flex;align-items:center;justify-content:center;background:#1a1a1a;will-change:transform,opacity;z-index:2;box-shadow:10px 0 28px rgba(0,0,0,.5);}
.fb-fold img{width:100%;height:100%;object-fit:contain;display:block;}
.fb-fold.fold-next{animation:fb-page-next 1.15s cubic-bezier(.42,.05,.3,1) forwards;}
.fb-fold.fold-prev{animation:fb-page-prev 1.15s cubic-bezier(.42,.05,.3,1) forwards;}
@keyframes fb-page-next{0%{transform:rotateY(0);opacity:1}55%{opacity:1}100%{transform:rotateY(-160deg);opacity:0}}
@keyframes fb-page-prev{0%{transform:rotateY(-160deg);opacity:0}45%{opacity:1}100%{transform:rotateY(0);opacity:1}}
.fb-nav-btn{flex:0 0 auto;background:rgba(255,255,255,.08);border:none;color:rgba(255,255,255,.7);font-size:38px;font-weight:100;width:40px;height:72px;cursor:pointer;border-radius:3px;transition:background .2s;display:flex;align-items:center;justify-content:center;}
.fb-nav-btn:hover{background:rgba(255,255,255,.18);color:#fff;}
.fb-nav-btn:disabled{opacity:.2;cursor:default;}
@keyframes fb-flip-out-r{from{transform:rotateY(0);filter:brightness(1)}to{transform:rotateY(-88deg);filter:brightness(.45)}}
@keyframes fb-flip-in-r{from{transform:rotateY(88deg);filter:brightness(.45)}to{transform:rotateY(0);filter:brightness(1)}}
@keyframes fb-flip-out-l{from{transform:rotateY(0);filter:brightness(1)}to{transform:rotateY(88deg);filter:brightness(.45)}}
@keyframes fb-flip-in-l{from{transform:rotateY(-88deg);filter:brightness(.45)}to{transform:rotateY(0);filter:brightness(1)}}
#fb-rp.anim-out{animation:fb-flip-out-r .42s cubic-bezier(.55,.06,.68,.19) forwards;}
#fb-rp.anim-in{animation:fb-flip-in-r .5s cubic-bezier(.17,.67,.3,1) forwards;}
#fb-lp.anim-out{animation:fb-flip-out-l .42s cubic-bezier(.55,.06,.68,.19) forwards;}
#fb-lp.anim-in{animation:fb-flip-in-l .5s cubic-bezier(.17,.67,.3,1) forwards;}
#fb-book.fb-single #fb-lp{display:none!important;}
#fb-book.fb-single #fb-rp{flex:1;border-left:none;}
#fb-book.fb-single #fb-rp img{object-fit:contain;}
.pdf-btn{display:inline-block;background:rgba(250,246,193,.1);border:none;color:rgba(250,246,193,.9);font-family:Verdana,sans-serif;font-size:10pt;padding:5px 16px;margin:3px 4px 3px 0;border-radius:999px;cursor:pointer;text-decoration:none;transition:background .2s;}
.pdf-btn svg{width:15px;height:15px;vertical-align:-2px;margin-right:7px;stroke:currentColor;fill:none;stroke-width:2;stroke-linecap:round;stroke-linejoin:round;}
.pdf-btn:hover{background:rgba(250,246,193,.22);color:#fff;}
.proj-inline-img{display:block;margin:14px auto 18px;max-width:92%;border-radius:3px;box-shadow:0 4px 18px rgba(0,0,0,.5);}