:root{
  --bg:#0b1220; --bg2:#111a2e; --card:#151f36; --card2:#1b2742;
  --txt:#e7ecf5; --sub:#9aa8c3; --line:#25345a;
  --accent:#4f8cff; --accent2:#7aa5ff; --danger:#ff6b6b; --ok:#3ddc97;
  --chatw:400px;
}
body.light{
  --bg:#f4f6fb; --bg2:#ffffff; --card:#ffffff; --card2:#eef1f8;
  --txt:#1c2333; --sub:#5b6883; --line:#d7dff0;
  --accent:#2f6fe4; --accent2:#1d4fa8;
}
*{box-sizing:border-box;margin:0;padding:0}
html,body{height:100%}
body{background:var(--bg);color:var(--txt);font-family:"Segoe UI",system-ui,-apple-system,Roboto,"Noto Sans Devanagari",sans-serif;transition:background .25s,color .25s}
.hidden{display:none!important}
button{font-family:inherit}

/* ---------- topbar ---------- */
#topbar{position:sticky;top:0;z-index:50;display:flex;align-items:center;justify-content:space-between;gap:12px;padding:10px 18px;background:var(--bg2);border-bottom:1px solid var(--line);backdrop-filter:blur(8px)}
.brand{display:flex;align-items:center;gap:12px;cursor:pointer}
.logo{font-size:30px}
.brand h1{font-size:19px;font-weight:800;letter-spacing:.3px}
.brand p{font-size:11px;color:var(--sub)}
.actions{display:flex;gap:8px;align-items:center}

/* ---------- buttons ---------- */
.btn{background:var(--card2);color:var(--txt);border:1px solid var(--line);border-radius:10px;padding:9px 14px;font-size:13px;font-weight:600;cursor:pointer;transition:.15s}
.btn:hover{border-color:var(--accent);transform:translateY(-1px)}
.btn.primary{background:var(--accent);border-color:var(--accent);color:#fff}
.btn.primary:hover{background:var(--accent2)}
.btn.small{padding:6px 10px;font-size:12px;border-radius:8px}

/* ---------- main ---------- */
main{max-width:1200px;margin:0 auto;padding:22px 18px 80px}
#library-toolbar{display:flex;align-items:center;justify-content:space-between;gap:12px;margin-bottom:18px;flex-wrap:wrap}
#library-toolbar h2{font-size:22px}
#libSearch{background:var(--card);border:1px solid var(--line);color:var(--txt);border-radius:10px;padding:9px 14px;width:240px;font-size:13px}
#libSearch:focus{outline:none;border-color:var(--accent)}

.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(230px,1fr));gap:16px}
.book-card{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:18px;cursor:pointer;transition:.18s;position:relative;display:flex;flex-direction:column;gap:8px}
.book-card:hover{border-color:var(--accent);transform:translateY(-3px);box-shadow:0 10px 30px rgba(0,0,0,.25)}
.bc-icon{font-size:36px;line-height:1}
.bc-title{font-size:14.5px;font-weight:700;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.bc-meta{font-size:11.5px;color:var(--sub)}
.bc-del{position:absolute;top:10px;right:10px;background:none;border:none;color:var(--sub);font-size:15px;cursor:pointer;opacity:0;transition:.15s}
.book-card:hover .bc-del{opacity:1}
.bc-del:hover{color:var(--danger)}

.empty{text-align:center;padding:70px 20px;color:var(--sub)}
.empty-icon{font-size:60px;margin-bottom:12px}
.empty h3{color:var(--txt);margin-bottom:6px}

/* ---------- reader ---------- */
#view-reader{max-width:820px;margin:0 auto}
#reader-toolbar{display:flex;align-items:center;gap:8px;margin-bottom:10px;flex-wrap:wrap}
#reader-toolbar h2{font-size:16px;flex:1;min-width:140px}
#readerPages{font-size:12px;color:var(--sub);white-space:nowrap}
.spacer{flex:1}
#reader-content{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:38px 44px;min-height:62vh;line-height:1.9;font-size:17px;white-space:pre-wrap;word-wrap:break-word;box-shadow:0 4px 24px rgba(0,0,0,.12)}
#reader-content .hit{background:rgba(255,214,0,.35);border-radius:4px;padding:1px 2px}
#reader-nav{display:flex;align-items:center;justify-content:space-between;margin-top:14px;gap:10px}
#pageIndicator{font-size:13px;color:var(--sub);font-weight:600}
.searchbar{display:flex;align-items:center;gap:8px;background:var(--card);border:1px solid var(--line);border-radius:10px;padding:8px 12px;margin-bottom:10px}
.searchbar input{flex:1;background:none;border:none;color:var(--txt);font-size:13px}
.searchbar input:focus{outline:none}
#searchCount{font-size:12px;color:var(--sub);white-space:nowrap}

/* ---------- chat ---------- */
#chat-panel{position:fixed;top:64px;right:14px;bottom:14px;width:var(--chatw);max-width:calc(100vw - 24px);background:var(--bg2);border:1px solid var(--line);border-radius:16px;display:flex;flex-direction:column;z-index:60;box-shadow:0 20px 60px rgba(0,0,0,.4);overflow:hidden}
#chat-head{display:flex;align-items:center;justify-content:space-between;padding:12px 14px;border-bottom:1px solid var(--line);font-weight:700;font-size:14px;background:var(--card)}
#chat-messages{flex:1;overflow-y:auto;padding:14px;display:flex;flex-direction:column;gap:12px}
.msg{max-width:88%;padding:10px 13px;border-radius:12px;font-size:13.5px;line-height:1.65;white-space:pre-wrap;word-wrap:break-word;animation:pop .18s ease}
@keyframes pop{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:none}}
.msg.user{align-self:flex-end;background:var(--accent);color:#fff;border-bottom-right-radius:4px}
.msg.ai{align-self:flex-start;background:var(--card);border:1px solid var(--line);border-bottom-left-radius:4px}
.msg.ai b,.msg.ai strong{color:var(--accent2)}
.msg.err{align-self:flex-start;background:rgba(255,107,107,.12);border:1px solid var(--danger);color:var(--danger)}
#chat-suggestions{display:flex;gap:6px;padding:0 12px 8px;flex-wrap:wrap}
.chip{background:var(--card2);border:1px solid var(--line);border-radius:20px;padding:6px 11px;font-size:11.5px;cursor:pointer;color:var(--sub);transition:.15s}
.chip:hover{border-color:var(--accent);color:var(--txt)}
#chat-input-row{display:flex;gap:8px;padding:10px}
#chat-input{flex:1;background:var(--card);border:1px solid var(--line);border-radius:10px;color:var(--txt);padding:10px;font-size:13px;resize:none;font-family:inherit}
#chat-input:focus{outline:none;border-color:var(--accent)}
#btnSend{background:var(--accent);border:none;color:#fff;border-radius:10px;width:44px;font-size:16px;cursor:pointer}
#btnSend:disabled{opacity:.5;cursor:wait}

/* ---------- modal ---------- */
.modal{position:fixed;inset:0;background:rgba(5,8,16,.72);backdrop-filter:blur(4px);display:flex;align-items:center;justify-content:center;z-index:100;padding:16px;animation:fade .2s ease}
@keyframes fade{from{opacity:0}to{opacity:1}}
.modal-box{background:var(--bg2);border:1px solid var(--line);border-radius:18px;padding:24px;width:100%;max-width:520px;max-height:92vh;overflow-y:auto;box-shadow:0 30px 80px rgba(0,0,0,.5)}
.modal-box h3{margin-bottom:16px;font-size:17px}
.dropzone{border:2px dashed var(--line);border-radius:16px;padding:34px 20px;text-align:center;color:var(--sub);transition:.2s}
.dropzone.over{border-color:var(--accent);background:rgba(79,140,255,.08)}
.dz-icon{font-size:44px;margin-bottom:10px}
.dropzone p{margin-bottom:12px;line-height:1.7}
.progress-wrap{margin-top:14px;text-align:center}
.progress-bar{height:12px;background:var(--card2);border-radius:8px;overflow:hidden;border:1px solid var(--line)}
.progress-bar::after{content:"";display:block;height:100%;width:0%;background:var(--accent);transition:width .15s;border-radius:8px}
#progress-text{margin-top:8px;font-size:12.5px;color:var(--sub)}
.note{font-size:11.5px;color:var(--sub);margin-top:12px;line-height:1.6}
.modal-buttons{display:flex;gap:8px;justify-content:flex-end;margin-top:16px}
.lbl{display:block;font-size:12.5px;font-weight:700;margin:14px 0 6px;color:var(--sub);text-transform:uppercase;letter-spacing:.4px}
.hint{text-transform:none;font-weight:400;color:var(--sub);font-size:11px}
.seg{display:flex;gap:8px}
.seg-btn{flex:1;background:var(--card);border:1px solid var(--line);color:var(--txt);padding:9px;border-radius:9px;cursor:pointer;font-size:13px}
.seg-btn.on{background:var(--accent);border-color:var(--accent);color:#fff}
select,input[type=password],input[type=text]{width:100%;background:var(--card);border:1px solid var(--line);color:var(--txt);border-radius:9px;padding:9px 12px;font-size:13px}
select:focus,input:focus{outline:none;border-color:var(--accent)}
.keyfield{margin-top:4px}

.toast{position:fixed;bottom:24px;left:50%;transform:translateX(-50%);background:var(--txt);color:var(--bg);padding:11px 20px;border-radius:12px;font-size:13px;font-weight:600;z-index:200;box-shadow:0 10px 30px rgba(0,0,0,.4);animation:pop .2s}

/* ---------- responsive ---------- */
@media(max-width:700px){
  #reader-content{padding:24px 18px;font-size:16px}
  main{padding:16px 12px 80px}
  #libSearch{width:100%}
  .brand p{display:none}
  #chat-panel{top:auto;left:10px;right:10px;bottom:10px;height:72vh}
}
@media print{
  body{background:#fff}
  #topbar,#reader-nav,#chat-panel{display:none!important}
  #reader-content{border:none;box-shadow:none;background:#fff;color:#000}
}