:root{
  --bg:#0b1220; --bg2:#111a2e; --card:#16223b; --card2:#1c2a47; --elev:#22335a;
  --border:#28385c; --text:#e8edf7; --muted:#93a4c4; --dim:#6b7ba0;
  --accent:#5b8cff; --accent2:#7c5cff; --good:#2fd07a; --bad:#ff5c6c; --warn:#ffc24b;
  --radius:14px; --shadow:0 10px 30px rgba(0,0,0,.35);
  --maxw:1180px;
}
@media (prefers-color-scheme: light){
  :root{ --bg:#f4f7fc; --bg2:#eaf0fb; --card:#ffffff; --card2:#f7f9fd; --elev:#eef3fc;
    --border:#dce6f5; --text:#0f1b33; --muted:#506485; --dim:#8294b5;
    --accent:#2f6bff; --accent2:#6a45ff; --good:#15a85b; --bad:#e23744; --warn:#c98a00;
    --shadow:0 8px 24px rgba(20,40,80,.12); }
}
*{box-sizing:border-box}
html,body{margin:0;padding:0;height:100%}
body{
  font-family:'Inter',system-ui,-apple-system,Segoe UI,Roboto,sans-serif;
  background:var(--bg); color:var(--text);
  -webkit-font-smoothing:antialiased; line-height:1.5;
}
#app{min-height:100%}
a{color:var(--accent);text-decoration:none}
button{font-family:inherit}
hr{border:none;border-top:1px solid var(--border);margin:14px 0}

/* layout */
.wrap{max-width:var(--maxw);margin:0 auto;padding:0 16px}
.topbar{
  position:sticky;top:0;z-index:40;
  background:linear-gradient(180deg,var(--bg2),var(--bg2) 70%,transparent);
  backdrop-filter:blur(8px);
  border-bottom:1px solid var(--border);
}
.topbar .wrap{display:flex;align-items:center;gap:14px;height:56px}
.brand{font-weight:800;font-size:17px;letter-spacing:-.2px;white-space:nowrap}
.brand span{color:var(--accent)}
.tabs{display:flex;gap:2px;margin-left:auto;overflow-x:auto;scrollbar-width:none}
.tabs::-webkit-scrollbar{display:none}
.tab{
  border:none;background:transparent;color:var(--muted);cursor:pointer;
  padding:8px 13px;border-radius:9px;font-size:14px;font-weight:600;white-space:nowrap;
}
.tab:hover{color:var(--text);background:var(--card)}
.tab.active{color:#fff;background:var(--accent)}
@media (prefers-color-scheme: light){ .tab.active{color:#fff} }
.userbox{display:flex;align-items:center;gap:8px;margin-left:auto;white-space:nowrap}
@media (max-width:720px){ .userbox .pill{display:none} }

/* cards & sections */
.section{padding:18px 16px 80px}
.card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:16px;box-shadow:var(--shadow)}
.grid{display:grid;gap:14px}
.grid-2{grid-template-columns:repeat(auto-fit,minmax(280px,1fr))}
.grid-3{grid-template-columns:repeat(auto-fit,minmax(220px,1fr))}
.muted{color:var(--muted)} .dim{color:var(--dim)}
h1,h2,h3{margin:0 0 6px;letter-spacing:-.3px}
h1{font-size:24px} h2{font-size:19px} h3{font-size:16px}
.pill{display:inline-flex;align-items:center;gap:6px;padding:3px 10px;border-radius:999px;font-size:12px;font-weight:600;background:var(--elev);color:var(--muted);border:1px solid var(--border)}
.pill.accent{background:rgba(91,140,255,.16);color:var(--accent);border-color:transparent}
.pill.good{background:rgba(47,208,122,.16);color:var(--good);border-color:transparent}
.pill.bad{background:rgba(255,92,108,.16);color:var(--bad);border-color:transparent}
.pill.warn{background:rgba(255,194,75,.16);color:var(--warn);border-color:transparent}
.pill.ped{background:rgba(245,158,11,.22);color:#f59e0b;border-color:transparent}

/* Explanation panel (learn mode) */
.exp-panel{margin-top:14px;padding:14px 16px;border-radius:12px;background:var(--card2);border:1px solid var(--border)}
.exp-verdict{font-weight:700;padding:8px 12px;border-radius:8px;margin-bottom:10px}
.exp-verdict.good{background:rgba(47,208,122,.14);color:var(--good)}
.exp-verdict.bad{background:rgba(255,92,108,.14);color:var(--bad)}
.exp-section{margin-top:10px}
.exp-section:first-of-type{margin-top:0}
.exp-label{font-size:12px;font-weight:700;color:var(--muted);margin-bottom:4px;text-transform:uppercase;letter-spacing:.04em}
.exp-text{font-size:14px;line-height:1.5;color:var(--text)}
.exp-wrong{display:flex;gap:8px;padding:4px 0;font-size:13px;line-height:1.45}
.exp-wrong-letter{flex:0 0 22px;height:22px;width:22px;border-radius:50%;background:rgba(255,92,108,.18);color:var(--bad);font-weight:700;display:flex;align-items:center;justify-content:center;font-size:11px}
.exp-wrong-text{flex:1;color:var(--text)}

/* Key findings highlighting in learn mode */
.drug-class{font-size:11px;color:var(--muted);font-weight:400;margin-left:2px;font-style:italic}
.kf{border-radius:3px;padding:1px 3px;font-weight:600}
.kf-value{background:rgba(91,140,255,.22);color:#5b8cff;border-bottom:2px solid #5b8cff}
.kf-symptom{background:rgba(255,194,75,.22);color:#ffc24b}
.kf-syndrome{background:rgba(255,92,108,.22);color:#ff5c6c;font-weight:700}
.kf-drug{background:rgba(47,208,122,.22);color:#2fd07a}
.kf-lab{background:rgba(168,85,247,.22);color:#a855f7}
.kf-sign{background:rgba(245,158,11,.22);color:#f59e0b}
/* Legend for key findings */
.kf-legend{display:flex;flex-wrap:wrap;gap:8px;margin-top:8px;font-size:11px;color:var(--muted)}
.kf-legend span{display:inline-flex;align-items:center;gap:4px}
.kf-legend i{display:inline-block;width:12px;height:12px;border-radius:3px}

/* buttons */
.btn{display:inline-flex;align-items:center;gap:8px;justify-content:center;cursor:pointer;border:1px solid var(--border);background:var(--card2);color:var(--text);padding:10px 16px;border-radius:10px;font-weight:600;font-size:14px;transition:.15s}
.btn:hover{background:var(--elev);border-color:var(--accent)}
.btn:disabled{opacity:.5;cursor:not-allowed}
.btn.primary{background:var(--accent);border-color:var(--accent);color:#fff}
.btn.primary:hover{filter:brightness(1.08)}
.btn.ghost{background:transparent}
.btn.sm{padding:6px 11px;font-size:13px;border-radius:8px}
.btn.block{width:100%}
.btnrow{display:flex;gap:8px;flex-wrap:wrap}

/* question */
.q-card{margin-bottom:14px}
.q-meta{display:flex;flex-wrap:wrap;gap:6px;margin-bottom:10px}
.q-text{font-size:16px;line-height:1.55;margin-bottom:14px;white-space:pre-wrap;word-wrap:break-word}
.opt{display:flex;gap:12px;align-items:flex-start;padding:12px 13px;border:1px solid var(--border);border-radius:10px;margin-bottom:8px;cursor:pointer;transition:.12s;background:var(--card2)}
.opt:hover{border-color:var(--accent);background:var(--elev)}
.opt.selected{border-color:var(--accent);background:rgba(91,140,255,.14)}
.opt.correct{border-color:var(--good);background:rgba(47,208,122,.16)}
.opt.wrong{border-color:var(--bad);background:rgba(255,92,108,.14)}
.opt .letter{flex:0 0 auto;width:26px;height:26px;border-radius:7px;display:flex;align-items:center;justify-content:center;font-weight:700;font-size:13px;background:var(--elev);color:var(--muted)}
.opt.correct .letter{background:var(--good);color:#062}
.opt.wrong .letter{background:var(--bad);color:#fff}
.opt .otext{flex:1;font-size:15px;white-space:pre-wrap;word-wrap:break-word}
.opt.disabled{cursor:default}

/* clickable tokens inside text */
.drug{color:var(--accent2);cursor:pointer;border-bottom:1px dotted var(--accent2);font-weight:600}
.drug:hover{background:rgba(124,92,255,.16)}
.lab{color:var(--warn);cursor:pointer;border-bottom:1px dotted var(--warn);font-weight:600}
.lab:hover{background:rgba(255,194,75,.16)}

/* explanation block */
.exp{margin-top:10px;padding:12px;border-radius:10px;background:var(--bg2);border:1px solid var(--border);font-size:14px}
.exp .h{font-weight:700;margin-bottom:6px;display:flex;gap:8px;align-items:center}
.exp .why{margin:6px 0;padding:7px 10px;border-radius:8px;background:var(--card);font-size:13px}
.exp .why.wrong{border-left:3px solid var(--bad)}
.exp .why.right{border-left:3px solid var(--good)}
.exp .concept{margin-top:8px}

/* modal */
.modal-bg{position:fixed;inset:0;background:rgba(0,0,0,.55);z-index:80;display:flex;align-items:center;justify-content:center;padding:16px}
.modal{background:var(--card);border:1px solid var(--border);border-radius:16px;max-width:560px;width:100%;max-height:86vh;overflow:auto;box-shadow:0 24px 60px rgba(0,0,0,.5);padding:18px}
.modal h3{margin-top:0}
.modal .close{float:right;cursor:pointer;color:var(--muted);font-size:22px;line-height:1;border:none;background:transparent;padding:4px}
.modal .close:hover{color:var(--text)}
.kv{display:grid;grid-template-columns:130px 1fr;gap:6px 12px;font-size:14px;margin:10px 0}
.kv .k{color:var(--muted);font-weight:600}
.kv .v{color:var(--text)}

/* filters */
.filters{display:flex;flex-wrap:wrap;gap:10px;align-items:end;margin-bottom:14px}
.field{display:flex;flex-direction:column;gap:4px;font-size:12px;color:var(--muted)}
.field select,.field input{background:var(--card2);border:1px solid var(--border);color:var(--text);border-radius:9px;padding:8px 10px;font-size:14px;font-family:inherit}
.search{flex:1;min-width:200px}

/* stats / progress */
.stat{display:flex;flex-direction:column;gap:2px}
.stat .n{font-size:24px;font-weight:800}
.stat .l{font-size:12px;color:var(--muted)}
.bar{height:8px;border-radius:6px;background:var(--elev);overflow:hidden;margin:4px 0}
.bar > div{height:100%;background:var(--good);transition:width .4s}
.list{display:flex;flex-direction:column;gap:6px}
.list .row{display:flex;justify-content:space-between;gap:10px;padding:9px 11px;border-radius:9px;background:var(--card2);border:1px solid var(--border);font-size:14px;align-items:center}
.row .grow{flex:1;min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}

/* flashcards */
.flash{background:var(--card);border:1px solid var(--border);border-radius:16px;padding:24px;text-align:center;min-height:240px;display:flex;flex-direction:column;justify-content:center;cursor:pointer}
.flash .fc-q{font-size:18px;font-weight:600;margin-bottom:12px}
.flash .fc-a{font-size:16px;color:var(--good)}
.flash .fc-h{color:var(--dim);font-size:13px;margin-top:14px}

/* timer */
.timer{font-variant-numeric:tabular-nums;font-weight:800;font-size:18px}
.timer.warn{color:var(--warn)} .timer.bad{color:var(--bad)}

/* empty / loading */
.empty{text-align:center;padding:50px 20px;color:var(--muted)}
.spinner{width:34px;height:34px;border:3px solid var(--border);border-top-color:var(--accent);border-radius:50%;animation:sp 1s linear infinite;margin:0 auto 12px}
@keyframes sp{to{transform:rotate(360deg)}}

/* toast */
.toast{position:fixed;bottom:18px;left:50%;transform:translateX(-50%);background:var(--elev);color:var(--text);padding:11px 18px;border-radius:10px;border:1px solid var(--border);box-shadow:var(--shadow);z-index:90;font-size:14px;opacity:0;transition:.25s;pointer-events:none}
.toast.show{opacity:1;bottom:30px}

/* responsive */
@media(max-width:640px){
  .brand{font-size:15px}
  .tab{padding:7px 10px;font-size:13px}
  h1{font-size:20px}
  .q-text{font-size:15px}
  .kv{grid-template-columns:110px 1fr}
  .section{padding:14px 12px 70px}
  .topbar .wrap{gap:8px;height:52px}
  .tabs{gap:1px}
  .tab{padding:6px 8px;font-size:12px}
  .userbox{gap:6px}
  .userbox .btn{padding:5px 8px;font-size:12px}
  .filters{gap:8px}
  .filters .field{min-width:100%}
  .grid-2{grid-template-columns:1fr}
  .grid-3{grid-template-columns:1fr}
  .q-meta{gap:4px}
  .q-meta .pill{font-size:10px;padding:2px 7px}
  .opt{padding:9px 10px}
  .opt .otext{font-size:14px}
  .opt .letter{width:26px;height:26px;font-size:12px}
  .exp-panel{padding:10px 12px}
  .exp-wrong{font-size:12px}
  .btnrow{gap:6px}
  .btn{padding:8px 12px;font-size:13px}
  .btn.sm{padding:6px 9px;font-size:12px}
  /* Grid nav: wrap into rows instead of 20-column stretch */
  .nav-grid{grid-template-columns:repeat(10,1fr) !important;gap:4px}
  .nav-grid .btn{padding:5px 0;font-size:11px;min-height:32px}
  /* Pager: make it scrollable horizontally */
  .pager{flex-wrap:wrap;justify-content:center}
  .pager .pg-num{min-width:36px;text-align:center}
  .card{padding:12px}
  .modal{max-width:94vw;max-height:88vh;padding:14px}
  h3{font-size:16px}
  .stat .n{font-size:24px}
  .flash{padding:24px 16px}
  .fc-q{font-size:18px}
  .timer{font-size:18px}
}

/* Tablet adjustments */
@media(max-width:900px) and (min-width:641px){
  .nav-grid{grid-template-columns:repeat(15,1fr) !important}
}

/* Nav grid base */
.nav-grid{display:grid;grid-template-columns:repeat(20,1fr);gap:5px;margin-top:12px}
.nav-grid .btn{padding:6px 0;justify-content:center;font-size:12px;min-height:34px}

/* Pager with numbered pages */
.pager{display:flex;gap:4px;align-items:center;justify-content:center;flex-wrap:wrap;margin-top:12px}
.pager .btn{min-width:38px;justify-content:center}
.pager .pg-num.active{background:var(--accent);color:#fff}
.pager .pg-num.ellipsis{background:transparent;border:none;color:var(--muted);cursor:default}
.pager-info{flex:0 0 100%;text-align:center;color:var(--muted);font-size:12px;margin-bottom:6px}