:root{
  --deu:#082b5c;
  --deu-2:#0c3d7d;
  --paper:#fff;
  --bg:#e9eef5;
  --line:rgba(8,43,92,.14);
  --shadow:0 24px 70px rgba(6,25,52,.23),0 5px 16px rgba(6,25,52,.15);
  --zoom:1;
}
*{box-sizing:border-box}
html,body{height:100%;margin:0}
body{font-family:Arial,Helvetica,sans-serif;background:var(--bg);color:#142238;overflow:hidden}
button,input,a{font:inherit}
button{border:0;cursor:pointer}
.app{height:100%;display:grid;grid-template-rows:68px 1fr 58px;background:radial-gradient(circle at 50% 38%,#fff 0,#f5f8fc 28%,#e5ebf3 78%,#dce4ee 100%)}
.topbar{display:flex;align-items:center;justify-content:space-between;padding:0 22px;background:linear-gradient(100deg,var(--deu),var(--deu-2));color:#fff;box-shadow:0 2px 12px rgba(0,0,0,.14);z-index:20}
.brand{display:flex;align-items:center;gap:13px;min-width:0}
.deu-mark{width:42px;height:42px;border:2px solid rgba(255,255,255,.9);border-radius:50%;display:grid;place-items:center;font-size:12px;font-weight:800;letter-spacing:.4px;flex:0 0 auto}
.brand-text{display:flex;flex-direction:column;min-width:0;line-height:1.15}
.brand-text strong{font-size:15px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.brand-text span{font-size:12px;opacity:.78;margin-top:4px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.pdf-link{display:inline-flex;align-items:center;justify-content:center;min-width:46px;height:34px;padding:0 12px;border:1px solid rgba(255,255,255,.35);border-radius:8px;color:#fff;text-decoration:none;font-weight:700;font-size:12px;background:rgba(255,255,255,.08)}
.pdf-link:hover{background:rgba(255,255,255,.17)}
.reader{position:relative;min-height:0;display:grid;grid-template-columns:64px 1fr 64px;align-items:center}
.viewport{height:100%;min-width:0;display:flex;align-items:center;justify-content:center;overflow:auto;padding:20px;touch-action:pan-y pinch-zoom}
.book{position:relative;display:flex;align-items:stretch;justify-content:center;transform:scale(var(--zoom));transform-origin:center center;perspective:2400px;transition:width .24s ease,height .24s ease;filter:drop-shadow(0 10px 28px rgba(8,33,65,.09))}
.page,.flip-card{position:relative;background:var(--paper);overflow:hidden;box-shadow:var(--shadow);backface-visibility:hidden;-webkit-backface-visibility:hidden}
.page img,.flip-face img{display:block;width:100%;height:100%;object-fit:contain;background:#fff;user-select:none;-webkit-user-drag:none}
.page.left{border-radius:5px 1px 1px 5px}
.page.right{border-radius:1px 5px 5px 1px}
.page.left::after,.page.right::before{content:"";position:absolute;top:0;bottom:0;width:24px;pointer-events:none}
.page.left::after{right:0;background:linear-gradient(90deg,transparent,rgba(0,0,0,.11))}
.page.right::before{left:0;background:linear-gradient(90deg,rgba(0,0,0,.12),transparent)}
.blank-page{background:transparent;box-shadow:none}
.single-page{border-radius:6px}
.flip-card{position:absolute;top:0;z-index:12;transform-style:preserve-3d;box-shadow:none;overflow:visible}
.flip-card.from-right{left:50%;transform-origin:left center;animation:flipNext .66s cubic-bezier(.22,.62,.2,1) forwards}
.flip-card.from-left{left:0;transform-origin:right center;animation:flipPrev .66s cubic-bezier(.22,.62,.2,1) forwards}
.flip-face{position:absolute;inset:0;background:white;overflow:hidden;box-shadow:0 18px 40px rgba(5,24,51,.26);backface-visibility:hidden;-webkit-backface-visibility:hidden}
.flip-face.back{transform:rotateY(180deg)}
.flip-card.from-right .flip-face.front::after,.flip-card.from-left .flip-face.front::after{content:"";position:absolute;inset:0;animation:pageShade .66s ease both;background:linear-gradient(90deg,transparent,rgba(0,0,0,.15))}
@keyframes flipNext{from{transform:rotateY(0deg)}to{transform:rotateY(-180deg)}}
@keyframes flipPrev{from{transform:rotateY(0deg)}to{transform:rotateY(180deg)}}
@keyframes pageShade{0%,100%{opacity:.08}50%{opacity:.9}}
.edge-nav{width:42px;height:76px;border-radius:12px;background:rgba(8,43,92,.08);color:var(--deu);font-size:38px;line-height:1;justify-self:center;transition:.18s ease;z-index:8}
.edge-nav:hover{background:var(--deu);color:#fff;transform:scale(1.04)}
.edge-nav:disabled{opacity:.18;cursor:default;transform:none;background:rgba(8,43,92,.06);color:var(--deu)}
.toolbar{display:flex;align-items:center;justify-content:center;gap:10px;padding:8px 14px;background:#fff;border-top:1px solid var(--line);box-shadow:0 -2px 12px rgba(5,30,62,.05);z-index:20}
.toolbar button{height:36px;min-width:38px;padding:0 11px;border:1px solid var(--line);border-radius:8px;background:#f7f9fc;color:var(--deu);font-weight:700;font-size:18px}
.toolbar button:hover{background:#edf3fa}
.tool-group{display:flex;gap:5px}
.page-control{height:36px;display:flex;align-items:center;gap:6px;padding:0 9px;border:1px solid var(--line);border-radius:8px;background:#fff;color:#607086;font-size:13px}
.page-control input{width:38px;border:0;outline:0;background:transparent;text-align:right;font-weight:700;color:var(--deu)}
.separator{height:26px;width:1px;background:var(--line);margin:0 2px}
.zoom-label{display:grid;place-items:center;width:47px;font-size:12px;color:#607086}
.toolbar .wide-tool{font-size:13px;display:inline-flex;align-items:center;gap:6px}
.loading{width:160px;height:160px;display:grid;place-items:center;color:var(--deu);font-weight:700}
@media (max-width:760px){
  .app{grid-template-rows:58px 1fr 54px}
  .topbar{padding:0 12px}
  .deu-mark{width:36px;height:36px;font-size:11px}
  .brand-text strong{font-size:13px}.brand-text span{font-size:10px}
  .reader{grid-template-columns:40px 1fr 40px}
  .viewport{padding:12px 4px}
  .edge-nav{width:32px;height:64px;font-size:31px;border-radius:9px}
  .toolbar{gap:5px;padding:7px 6px;overflow-x:auto;justify-content:flex-start}
  .toolbar button{height:34px;min-width:34px;padding:0 8px}
  .wide-tool span,.separator,.zoom-label{display:none}
  .page-control{height:34px}
}
@media (max-width:430px){.brand-text span{display:none}.pdf-link{min-width:42px;padding:0 8px}.reader{grid-template-columns:32px 1fr 32px}.edge-nav{width:28px;height:58px}}