:root{--brand:#267DF4;--ink:#111827;--muted:#667085;--line:#E4E7EC;--soft:#E9EDF5}
*{box-sizing:border-box}html,body{height:100%}body{margin:0;background:radial-gradient(circle at top,#fff 0,#eef2f8 45%,#dde3ed 100%);color:var(--ink);font-family:Arial,sans-serif;overflow:hidden}
button,a,.button,input{font:inherit}.topbar{height:72px;background:#fff;border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;padding:0 22px;position:relative;z-index:20}
.brand{display:flex;align-items:center;gap:11px}.brand .mark{width:42px;height:42px;border-radius:13px;background:var(--brand);color:#fff;display:grid;place-items:center;font-weight:900}.brand>span:last-child{display:flex;flex-direction:column;line-height:1.1}.brand small{color:var(--muted);font-size:.75rem;margin-top:3px}
.top-actions{display:flex;gap:8px}.button,.controls button,.controls a{border:1px solid var(--line);background:#fff;border-radius:10px;min-height:38px;padding:8px 12px;text-decoration:none;color:var(--ink);font-weight:800;cursor:pointer}.button:hover,.controls button:hover,.controls a:hover{border-color:var(--brand)}
.viewer-shell{height:calc(100vh - 136px)}.thumb-panel{width:260px;background:#111827;color:#fff;overflow:auto;transform:translateX(-100%);transition:.25s;position:fixed;top:72px;bottom:64px;left:0;z-index:15;padding:16px;box-shadow:18px 0 45px rgba(15,23,42,.2)}.thumb-panel.open{transform:translateX(0)}.thumb-heading{display:flex;justify-content:space-between;align-items:center;margin-bottom:12px}.thumb-heading button{border:0;background:transparent;color:#fff;font-size:1.6rem;cursor:pointer}
.thumbs{display:grid;grid-template-columns:1fr 1fr;gap:10px}.thumb{border:2px solid transparent;background:#fff;border-radius:10px;padding:7px;cursor:pointer}.thumb.active{border-color:var(--brand)}.thumb img{width:100%;height:auto;display:block}.thumb span{display:block;color:#111827;font-weight:900;margin-top:4px}
.stage{height:100%;display:flex;align-items:center;justify-content:center;overflow:hidden;padding:22px 28px}.book-wrap{display:flex;align-items:center;justify-content:center;width:100%;height:100%;transform-origin:center center;transition:transform .18s ease}.flipbook{margin:auto;transition:transform .18s ease;will-change:transform}.flipbook .stf__parent{margin:auto!important;background:transparent!important}.flipbook canvas{background:transparent!important}.flipbook img{display:block;width:100%;height:100%;object-fit:contain;background:#fff}
.loading{width:min(440px,calc(100% - 40px));background:#fff;border:1px solid var(--line);border-radius:18px;padding:25px;box-shadow:0 24px 70px rgba(15,23,42,.12);text-align:center}.loading strong{display:block;font-size:1.25rem}.loading span{display:block;color:var(--muted);margin-top:6px}.progress{height:9px;background:#e9eef7;border-radius:999px;overflow:hidden;margin-top:18px}.progress span{display:block;width:0;height:100%;background:var(--brand);margin:0;transition:width .2s ease}
.controls{height:64px;background:#0A0D14;color:#fff;display:flex;align-items:center;justify-content:center;gap:9px;padding:10px;position:fixed;bottom:0;left:0;right:0;z-index:18;overflow:auto}.controls button,.controls a{background:#171C27;border-color:#2F3748;color:#fff;white-space:nowrap}.controls button:disabled{opacity:.42;cursor:not-allowed}.controls input{width:58px;background:#fff;border:0;border-radius:8px;padding:7px;text-align:center}.divider{width:1px;height:28px;background:#384154}.page-control{white-space:nowrap}.error-box{position:fixed;inset:90px 20px auto;max-width:740px;margin:auto;background:#fff0ee;color:#B42318;padding:18px;border-radius:14px;font-weight:800;z-index:25}
@media(max-width:760px){.topbar{height:64px;padding:0 12px}.brand .mark{width:36px;height:36px}.brand small{display:none}.top-actions .local-load{display:none}.viewer-shell{height:calc(100vh - 128px)}.thumb-panel{top:64px}.stage{padding:10px}.controls{justify-content:flex-start}.controls .divider{display:none}.book-wrap{align-items:center}}