:root{
  --radius:12px;
  --font-ui:system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
  --font-brand:Georgia,"Times New Roman",serif;
}
body[data-theme="dark"]{
  --bg1:#241c16; --bg2:#0e0b09;
  --panel:rgba(255,255,255,.06); --panel-hover:rgba(255,255,255,.12);
  --border:rgba(255,255,255,.12);
  --text:#f2ebe0; --muted:#a89c8b;
  --accent:#e8b04a; --accent-ink:#1a1410;
  --shadow:rgba(0,0,0,.65);
}
body[data-theme="light"]{
  --bg1:#f4efe4; --bg2:#d9cfbc;
  --panel:rgba(0,0,0,.05); --panel-hover:rgba(0,0,0,.10);
  --border:rgba(0,0,0,.14);
  --text:#2a221a; --muted:#6f6454;
  --accent:#c9831c; --accent-ink:#fff8ea;
  --shadow:rgba(60,40,10,.45);
}
*{box-sizing:border-box}
html,body{height:100%;margin:0}
[hidden]{display:none!important}
body{
  font-family:var(--font-ui); color:var(--text);
  background:radial-gradient(120% 90% at 50% 40%, var(--bg1) 0%, var(--bg2) 100%) fixed;
  display:flex; flex-direction:column; overflow:hidden;
  height:100dvh; overscroll-behavior:none;
  padding:env(safe-area-inset-top) env(safe-area-inset-right) env(safe-area-inset-bottom) env(safe-area-inset-left);
}

/* top bar */
.top{display:flex;align-items:center;gap:16px;padding:10px 18px;min-height:56px}
.brand{display:flex;align-items:center;gap:10px;font-family:var(--font-brand);font-size:20px;font-weight:700;letter-spacing:.2px;white-space:nowrap}
.title{flex:1;min-width:0;text-align:center;color:var(--muted);font-size:14px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.actions{display:flex;align-items:center;gap:8px}

.btn{
  appearance:none;border:1px solid var(--border);background:var(--panel);color:var(--text);
  font:inherit;font-size:14px;padding:8px 14px;border-radius:10px;cursor:pointer;white-space:nowrap;
  display:inline-flex;align-items:center;justify-content:center;gap:6px;transition:background .15s,transform .1s;
}
.btn:hover{background:var(--panel-hover)}
.btn:active{transform:translateY(1px)}
.btn:focus-visible,.drop:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
.btn.icon-only{padding:8px;width:38px;height:38px}
.btn.sm{width:34px;height:34px;padding:6px}
.btn.primary{background:var(--accent);color:var(--accent-ink);border-color:transparent;font-weight:600}
.btn.primary:hover{filter:brightness(1.08);background:var(--accent)}
.btn.big{font-size:16px;padding:12px 26px;border-radius:12px}

/* stage */
.stage{position:relative;flex:1;min-height:0;width:100%;align-self:stretch;display:flex;align-items:center;justify-content:center;padding:8px 64px}
.landing{width:100%;display:flex;justify-content:center}
.drop{
  max-width:620px;width:100%;text-align:center;padding:48px 32px;border-radius:24px;
  border:2px dashed var(--border);background:var(--panel);transition:border-color .15s,background .15s,transform .15s;
  display:flex;flex-direction:column;align-items:center;gap:6px;color:var(--text);
}
.drop svg{color:var(--accent);margin-bottom:6px}
.drop h1{font-family:var(--font-brand);font-size:28px;line-height:1.2;margin:4px 0 6px}
.drop p{margin:0 0 12px;color:var(--muted)}
.drop small{margin-top:16px;color:var(--muted);font-size:13px}
body.dragging .drop{border-color:var(--accent);background:var(--panel-hover);transform:scale(1.015)}

.book-host{display:none;position:relative;filter:drop-shadow(0 24px 30px var(--shadow))}
#book{width:100%;height:100%}
body.has-book .book-host{display:block}
body.has-book .landing{display:none}
.book-only{display:none}
body.has-book .book-only{display:inline-flex}
body.has-book .nav.book-only{display:flex}
body.has-book .bar.book-only{display:flex}

/* pages */
.page{background:#fff;overflow:hidden}
.page img{width:100%;height:100%;display:block;object-fit:fill;user-select:none;-webkit-user-drag:none;opacity:0;transition:opacity .25s}
.page.ready img{opacity:1}
.page::after{content:attr(data-n);position:absolute;inset:0;display:flex;align-items:center;justify-content:center;color:#b9b2a5;font:600 22px var(--font-brand);pointer-events:none}
.page.ready::after{display:none}
.page[data-density="hard"]{box-shadow:inset 0 0 0 1px rgba(0,0,0,.2)}

/* side nav arrows */
.nav{
  position:absolute;top:50%;transform:translateY(-50%);width:46px;height:46px;border-radius:50%;
  border:1px solid var(--border);background:var(--panel);color:var(--text);cursor:pointer;
  align-items:center;justify-content:center;transition:background .15s;z-index:5;
}
.nav:hover{background:var(--panel-hover)}
.nav.prev{left:10px}.nav.next{right:10px}
.nav:disabled{opacity:.3;cursor:default}

/* bottom bar */
.bar{align-items:center;justify-content:center;gap:10px;padding:10px 18px 14px;flex-wrap:wrap}
#slider{width:min(46vw,520px);accent-color:var(--accent);cursor:pointer}
.counter{display:flex;align-items:center;gap:6px;font-size:14px;color:var(--muted);margin-left:6px}
.counter input{
  width:64px;padding:6px 8px;border-radius:8px;border:1px solid var(--border);background:var(--panel);
  color:var(--text);font:inherit;text-align:center;-moz-appearance:textfield;
}
.counter input::-webkit-outer-spin-button,.counter input::-webkit-inner-spin-button{-webkit-appearance:none;margin:0}
.quality{display:flex;align-items:center;gap:6px;font-size:13px;color:var(--muted);margin-left:8px}
.quality select{background:var(--panel);color:var(--text);border:1px solid var(--border);border-radius:8px;padding:5px 8px;font:inherit}
.quality select option{color:#222}
.prep{font-size:12px;color:var(--muted);min-width:120px}

/* overlay + toast */
.overlay{position:fixed;inset:0;background:rgba(0,0,0,.55);backdrop-filter:blur(3px);display:flex;align-items:center;justify-content:center;z-index:50}
.overlay[hidden]{display:none}
.card{background:var(--bg1);color:var(--text);border:1px solid var(--border);border-radius:16px;padding:26px 34px;min-width:280px;text-align:center;display:flex;flex-direction:column;gap:14px;align-items:center;box-shadow:0 20px 50px rgba(0,0,0,.5)}
.spinner{width:30px;height:30px;border-radius:50%;border:3px solid var(--border);border-top-color:var(--accent);animation:spin .8s linear infinite}
@keyframes spin{to{transform:rotate(360deg)}}
.meter{width:240px;height:6px;border-radius:99px;background:var(--panel-hover);overflow:hidden}
.meter[hidden]{display:none}
#meter{height:100%;width:0;background:var(--accent);transition:width .15s}
.toast{position:fixed;bottom:76px;left:50%;transform:translateX(-50%);background:var(--bg1);color:var(--text);border:1px solid var(--border);padding:10px 16px;border-radius:10px;font-size:14px;z-index:60;box-shadow:0 10px 30px rgba(0,0,0,.4);max-width:90vw;text-align:center}
.toast[hidden]{display:none}

@media (max-width:720px){
  .stage{padding:6px 8px}
  .nav{display:none!important}
  .title{display:none}
  .brand span{display:none}
  .actions{margin-left:auto}
  #btnOpen{padding:8px 10px}
  .btn.primary{padding:8px 10px;font-size:13px}
  .top{gap:8px;padding:8px 10px}
  .quality{display:none}
  .prep{display:none}
  #slider{width:100%;order:5}
}

/* Reader mode (Kindle-style horizontal, one page at a time) */
.reader{position:absolute;inset:0;display:flex;overflow-x:auto;overflow-y:hidden;scroll-snap-type:x mandatory;
  scrollbar-width:none;-webkit-overflow-scrolling:touch;overscroll-behavior-x:contain;z-index:1}
.reader::-webkit-scrollbar{display:none}
.reader[hidden]{display:none}
.slide{flex:0 0 100%;height:100%;overflow:hidden;scroll-snap-align:center;scroll-snap-stop:always;display:flex;align-items:center;justify-content:center}
.slide .pg{position:relative;width:var(--pw);height:var(--ph);box-shadow:0 14px 34px var(--shadow);border-radius:2px}
body.slide .book-host{display:none!important}
body.slide .stage{padding:6px 0}
body.slide .nav{z-index:6}