:root{
  --bg:#0e1116; --bg2:#151a22; --card:#1b212b; --card2:#222a36;
  --line:#2c3542; --txt:#e8edf4; --dim:#9aa7b8; --dim2:#6d7c8f;
  --acc:#7c5cff; --acc2:#a78bfa; --ok:#33d69f; --bad:#ff5f6d; --warn:#ffb020;
  --maroon:#8b1a1a;
  --r:14px; --sh:0 6px 24px rgba(0,0,0,.35);
  --f:'Inter',system-ui,-apple-system,'Segoe UI',Roboto,sans-serif;
}
[data-theme="light"]{
  --bg:#f4f6fa; --bg2:#ffffff; --card:#ffffff; --card2:#f0f3f8;
  --line:#dde3ec; --txt:#141a22; --dim:#5a6779; --dim2:#8a97a8;
  --sh:0 4px 18px rgba(20,30,50,.08);
}
*{box-sizing:border-box;margin:0;padding:0}
html,body{height:100%}
body{background:var(--bg);color:var(--txt);font-family:var(--f);
  -webkit-font-smoothing:antialiased;line-height:1.55}
button{font-family:inherit;cursor:pointer;border:none;background:none;color:inherit}
a{color:var(--acc2);text-decoration:none}

/* ---------- layout ---------- */
.app{display:flex;min-height:100vh}
.side{width:236px;flex:0 0 236px;background:var(--bg2);border-right:1px solid var(--line);
  padding:20px 14px;display:flex;flex-direction:column;gap:6px;position:sticky;top:0;height:100vh;overflow-y:auto}
.brand{display:flex;align-items:center;gap:10px;padding:4px 8px 18px}
.brand .logo{width:34px;height:34px;border-radius:9px;background:linear-gradient(135deg,var(--maroon),#c0392b);
  display:grid;place-items:center;font-weight:800;font-size:14px;color:#fff;letter-spacing:-.5px}
.brand b{font-size:15px;letter-spacing:-.2px}
.brand span{display:block;font-size:11px;color:var(--dim2);font-weight:500}
.nav{display:flex;flex-direction:column;gap:2px}
.nav button{display:flex;align-items:center;gap:11px;padding:10px 12px;border-radius:10px;
  color:var(--dim);font-size:14px;font-weight:500;text-align:left;transition:.14s}
.nav button:hover{background:var(--card);color:var(--txt)}
.nav button.on{background:var(--acc);color:#fff;font-weight:600}
.nav .ic{width:18px;text-align:center;font-size:15px}
.side-foot{margin-top:auto;padding-top:14px;border-top:1px solid var(--line);
  display:flex;flex-direction:column;gap:8px}
.side-foot button{font-size:12px;color:var(--dim2);padding:6px 12px;border-radius:8px;text-align:left}
.side-foot button:hover{color:var(--txt);background:var(--card)}

.main{flex:1;min-width:0;padding:26px 30px 70px;max-width:1180px}
.head{display:flex;align-items:flex-end;justify-content:space-between;gap:16px;margin-bottom:22px;flex-wrap:wrap}
.head h1{font-size:25px;font-weight:700;letter-spacing:-.5px}
.head p{color:var(--dim);font-size:13.5px;margin-top:3px}

/* ---------- cards & grid ---------- */
.grid{display:grid;gap:14px}
.g4{grid-template-columns:repeat(4,1fr)}
.g3{grid-template-columns:repeat(3,1fr)}
.g2{grid-template-columns:repeat(2,1fr)}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:17px}
.card h3{font-size:13px;font-weight:600;color:var(--dim);margin-bottom:12px;
  text-transform:uppercase;letter-spacing:.6px}
.stat .v{font-size:29px;font-weight:750;letter-spacing:-1px;line-height:1.1}
.stat .l{font-size:12px;color:var(--dim);margin-top:3px}
.stat .s{font-size:11px;color:var(--dim2);margin-top:6px}

/* ---------- buttons ---------- */
.btn{background:var(--acc);color:#fff;padding:10px 17px;border-radius:10px;
  font-size:13.5px;font-weight:600;transition:.14s;display:inline-flex;align-items:center;gap:7px}
.btn:hover{filter:brightness(1.12)}
.btn.ghost{background:var(--card2);color:var(--txt);border:1px solid var(--line)}
.btn.ghost:hover{background:var(--line)}
.btn.sm{padding:7px 13px;font-size:12.5px}
.btn:disabled{opacity:.45;cursor:not-allowed}

/* ---------- progress ---------- */
.bar{height:7px;background:var(--card2);border-radius:99px;overflow:hidden}
.bar i{display:block;height:100%;border-radius:99px;background:var(--acc);transition:width .5s}
.ring{--p:0;width:104px;height:104px;border-radius:50%;display:grid;place-items:center;
  background:conic-gradient(var(--acc) calc(var(--p)*1%), var(--card2) 0)}
.ring .in{width:82px;height:82px;border-radius:50%;background:var(--card);
  display:grid;place-items:center;text-align:center}
.ring .in b{font-size:23px;font-weight:750;letter-spacing:-1px}
.ring .in span{font-size:10px;color:var(--dim);display:block}

/* ---------- plan ---------- */
.plan{display:flex;flex-direction:column;gap:9px}
.plan-item{display:flex;align-items:center;gap:13px;padding:13px 15px;border-radius:11px;
  background:var(--card2);border:1px solid transparent;transition:.14s;text-align:left;width:100%}
.plan-item:hover{border-color:var(--acc);transform:translateX(2px)}
.plan-item .em{font-size:19px}
.plan-item .tx{flex:1;min-width:0}
.plan-item .tx b{font-size:14px;font-weight:600;display:block}
.plan-item .tx span{font-size:12.5px;color:var(--dim)}

/* ---------- topic rows ---------- */
.trow{display:flex;align-items:center;gap:12px;padding:9px 0;border-bottom:1px solid var(--line)}
.trow:last-child{border-bottom:none}
.trow .nm{flex:0 0 190px;font-size:13.5px;font-weight:500;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.trow .bar{flex:1}
.trow .pc{flex:0 0 78px;text-align:right;font-size:12.5px;color:var(--dim);font-variant-numeric:tabular-nums}
.pill{font-size:10.5px;padding:2px 8px;border-radius:99px;font-weight:600;letter-spacing:.3px}
.pill.ok{background:rgba(51,214,159,.16);color:var(--ok)}
.pill.mid{background:rgba(255,176,32,.16);color:var(--warn)}
.pill.low{background:rgba(255,95,109,.16);color:var(--bad)}
.pill.new{background:var(--card2);color:var(--dim2)}

/* ---------- question / quiz ---------- */
.qwrap{max-width:760px;margin:0 auto}
.qmeta{display:flex;align-items:center;gap:9px;margin-bottom:14px;flex-wrap:wrap}
.tag{font-size:11px;padding:3px 9px;border-radius:7px;background:var(--card2);color:var(--dim);font-weight:600}
.tag.subj{background:rgba(124,92,255,.18);color:var(--acc2)}
.passage{background:var(--card2);border-left:3px solid var(--acc);padding:14px 16px;
  border-radius:0 10px 10px 0;font-size:13.5px;color:var(--dim);margin-bottom:16px;
  max-height:260px;overflow-y:auto;line-height:1.65}
.passage.tall{max-height:none}
.stem{font-size:17px;font-weight:500;line-height:1.6;margin-bottom:18px}
.opts{display:flex;flex-direction:column;gap:9px}
.opt{display:flex;align-items:flex-start;gap:12px;padding:13px 15px;border-radius:11px;
  background:var(--card);border:1.5px solid var(--line);text-align:left;font-size:14.5px;transition:.13s}
.opt:hover:not(:disabled){border-color:var(--acc);background:var(--card2)}
.opt .k{flex:0 0 25px;height:25px;border-radius:7px;background:var(--card2);
  display:grid;place-items:center;font-size:12px;font-weight:700;color:var(--dim)}
.opt.sel{border-color:var(--acc)}
.opt.right{border-color:var(--ok);background:rgba(51,214,159,.10)}
.opt.right .k{background:var(--ok);color:#062b1f}
.opt.wrong{border-color:var(--bad);background:rgba(255,95,109,.10)}
.opt.wrong .k{background:var(--bad);color:#3a0308}
.fb{margin-top:16px;padding:14px 16px;border-radius:11px;font-size:13.5px;line-height:1.6}
.fb.ok{background:rgba(51,214,159,.10);border:1px solid rgba(51,214,159,.3)}
.fb.no{background:rgba(255,95,109,.10);border:1px solid rgba(255,95,109,.3)}
.fb b{display:block;margin-bottom:4px;font-size:13px}

/* ---------- flashcard ---------- */
.fc-scene{perspective:1400px;max-width:640px;margin:0 auto}
.fc{position:relative;width:100%;min-height:380px;transform-style:preserve-3d;
  transition:transform .5s cubic-bezier(.4,.2,.2,1)}
.fc.flip{transform:rotateY(180deg)}
.fc-face{position:absolute;inset:0;backface-visibility:hidden;background:var(--card);
  border:1px solid var(--line);border-radius:18px;padding:30px;display:flex;
  flex-direction:column;justify-content:center;box-shadow:var(--sh)}
.fc-back{transform:rotateY(180deg);overflow-y:auto}
.fc-face{justify-content:flex-start;overflow-y:auto}
.fc-q{font-size:17px;font-weight:500;line-height:1.55;margin-bottom:16px}
.fc-opts{display:flex;flex-direction:column;gap:7px}
.fc-opt{display:flex;gap:10px;padding:9px 12px;border-radius:9px;background:var(--card2);
  font-size:14px;line-height:1.45}
.fc-opt b{flex:0 0 16px;color:var(--dim);font-weight:700;font-size:12px;padding-top:2px}
.fc-hint{text-align:center;color:var(--dim2);font-size:12px;margin-top:16px}
.cue{font-style:italic;font-weight:600;color:var(--acc2);text-decoration-color:var(--acc)}
u.cue{font-style:normal;text-underline-offset:3px}
.fc-a{font-size:15px}
.fc-a .lab{font-size:11px;color:var(--dim);text-transform:uppercase;letter-spacing:.6px;margin-bottom:6px}
.fc-a .ans{font-size:19px;font-weight:650;color:var(--ok);margin-bottom:14px;line-height:1.4}
.fc-rate{display:grid;grid-template-columns:repeat(4,1fr);gap:8px;max-width:640px;margin:18px auto 0}
.fc-rate button{padding:12px 6px;border-radius:11px;background:var(--card);
  border:1.5px solid var(--line);font-size:13px;font-weight:600;transition:.13s}
.fc-rate button:hover{transform:translateY(-2px)}
.fc-rate button small{display:block;font-size:10.5px;color:var(--dim2);font-weight:500;margin-top:2px}
.fc-rate .r0:hover{border-color:var(--bad);color:var(--bad)}
.fc-rate .r1:hover{border-color:var(--warn);color:var(--warn)}
.fc-rate .r2:hover{border-color:var(--acc);color:var(--acc2)}
.fc-rate .r3:hover{border-color:var(--ok);color:var(--ok)}

/* ---------- misc ---------- */
.chips{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:16px}
.chip{padding:7px 14px;border-radius:99px;background:var(--card);border:1px solid var(--line);
  font-size:13px;font-weight:500;transition:.13s}
.chip:hover{border-color:var(--acc)}
.chip.on{background:var(--acc);border-color:var(--acc);color:#fff;font-weight:600}
.prog-top{display:flex;align-items:center;gap:14px;margin-bottom:20px}
.prog-top .bar{flex:1}
.prog-top .n{font-size:12.5px;color:var(--dim);font-variant-numeric:tabular-nums;white-space:nowrap}
.timer{font-variant-numeric:tabular-nums;font-weight:650;font-size:15px;padding:5px 12px;
  border-radius:9px;background:var(--card2)}
.timer.low{background:rgba(255,95,109,.18);color:var(--bad)}
.spark{display:flex;align-items:flex-end;gap:3px;height:52px}
.spark i{flex:1;background:var(--acc);border-radius:3px 3px 0 0;min-height:3px;opacity:.85}
.spark i.z{background:var(--card2)}
.empty{text-align:center;padding:56px 20px;color:var(--dim)}
.empty .em{font-size:38px;margin-bottom:12px}
.empty b{display:block;font-size:16px;color:var(--txt);margin-bottom:5px}
.hidden{display:none!important}
.katex{font-size:1.03em}
.sr-note{font-size:11.5px;color:var(--dim2);margin-top:10px}
table.res{width:100%;border-collapse:collapse;font-size:13.5px}
table.res th,table.res td{padding:9px 10px;text-align:left;border-bottom:1px solid var(--line)}
table.res th{font-size:11px;text-transform:uppercase;letter-spacing:.5px;color:var(--dim);font-weight:600}
table.res td.num{text-align:right;font-variant-numeric:tabular-nums}

/* ---------- floating study coach ---------- */
.fab{position:fixed;right:22px;bottom:22px;width:58px;height:58px;border-radius:50%;
  background:linear-gradient(135deg,var(--acc),#5b8cff);color:#fff;display:grid;place-items:center;
  box-shadow:0 8px 26px rgba(124,92,255,.45);z-index:60;transition:.18s}
.fab:hover{transform:translateY(-3px) scale(1.05);box-shadow:0 12px 32px rgba(124,92,255,.55)}
.fab:active{transform:scale(.96)}
.fab .fab-ic{font-size:24px;line-height:1}
.fab.pulse::after{content:'';position:absolute;inset:0;border-radius:50%;
  border:2px solid var(--acc);animation:fabpulse 2.2s ease-out infinite}
@keyframes fabpulse{0%{transform:scale(1);opacity:.7}100%{transform:scale(1.55);opacity:0}}
.fab-badge{position:absolute;top:-3px;right:-3px;min-width:21px;height:21px;padding:0 6px;
  border-radius:99px;background:var(--bad);color:#fff;font-size:11px;font-weight:700;
  display:grid;place-items:center;border:2px solid var(--bg)}

.coach-overlay{position:fixed;right:22px;bottom:92px;width:370px;max-height:min(620px,calc(100vh - 130px));
  background:var(--card);border:1px solid var(--line);border-radius:18px;z-index:61;
  box-shadow:0 20px 60px rgba(0,0,0,.5);display:flex;flex-direction:column;overflow:hidden;
  transform-origin:bottom right;animation:coachIn .2s cubic-bezier(.3,1.2,.5,1)}
@keyframes coachIn{from{opacity:0;transform:scale(.9) translateY(12px)}to{opacity:1;transform:none}}
.coach-head{display:flex;align-items:center;justify-content:space-between;gap:10px;
  padding:15px 17px;border-bottom:1px solid var(--line);background:var(--card2)}
.coach-head b{font-size:14.5px;display:block}
.coach-head span{font-size:12px;color:var(--dim)}
.coach-head button{font-size:15px;color:var(--dim);width:28px;height:28px;border-radius:8px}
.coach-head button:hover{background:var(--line);color:var(--txt)}
.coach-body{padding:15px 17px;overflow-y:auto;display:flex;flex-direction:column;gap:13px}
.coach-metric{display:flex;align-items:center;gap:13px}
.coach-metric .ring{width:66px;height:66px;flex:0 0 66px}
.coach-metric .ring .in{width:52px;height:52px}
.coach-metric .ring .in b{font-size:16px}
.coach-metric .ring .in span{font-size:8px}
.coach-metric .mx{flex:1;min-width:0;font-size:12.5px;color:var(--dim);line-height:1.5}
.coach-sec{font-size:11px;font-weight:700;color:var(--dim2);text-transform:uppercase;letter-spacing:.6px}
.coach-act{display:flex;align-items:center;gap:11px;padding:11px 13px;border-radius:11px;
  background:var(--card2);border:1px solid transparent;text-align:left;width:100%;transition:.14s}
.coach-act:hover{border-color:var(--acc);transform:translateX(2px)}
.coach-act .em{font-size:17px}
.coach-act .tx{flex:1;min-width:0}
.coach-act .tx b{display:block;font-size:13px;font-weight:600}
.coach-act .tx span{font-size:11.5px;color:var(--dim);display:block;line-height:1.45}
.coach-weak{display:flex;align-items:center;gap:9px;font-size:12.5px;padding:5px 0}
.coach-weak .nm{flex:1;min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.coach-weak .bar{flex:0 0 62px}
.coach-note{font-size:11.5px;color:var(--dim2);line-height:1.5;
  background:var(--card2);padding:10px 12px;border-radius:10px}

/* ---------- ask the coach ---------- */
.ask{display:flex;flex-direction:column;gap:9px}
.ask-ctx{background:var(--card2);border-left:3px solid var(--acc);padding:9px 11px;
  border-radius:0 9px 9px 0;font-size:12.5px;line-height:1.5}
.ask-ctx .tag{margin-right:5px;margin-bottom:5px;display:inline-block}
.ask-chips{display:flex;gap:6px;flex-wrap:wrap}
.ask-chips .chip{font-size:11.5px;padding:5px 10px}
.ask-row{display:flex;gap:7px}
.ask-inp{flex:1;min-width:0;padding:9px 11px;border-radius:9px;background:var(--card2);
  border:1px solid var(--line);color:var(--txt);font-family:inherit;font-size:13px}
.ask-inp:focus{outline:none;border-color:var(--acc)}
.ask-out:empty{display:none}
.ask-a{background:var(--card2);border-radius:11px;padding:12px 14px;font-size:13px;line-height:1.6}
.ask-a>b{display:block;font-size:11px;text-transform:uppercase;letter-spacing:.6px;
  color:var(--acc2);margin-bottom:7px}
.ask-a p{margin:0 0 8px}
.ask-a p:last-child{margin-bottom:0}
.ask-a ul,.ask-a ol{margin:0 0 8px 17px}
.ask-a li{margin-bottom:4px}
.ask-a .muted{color:var(--dim2)}

/* ---------- storage warning ---------- */
.warnbar{position:sticky;top:0;z-index:70;background:rgba(255,176,32,.14);
  border-bottom:1px solid rgba(255,176,32,.35);color:var(--txt);
  padding:11px 44px 11px 16px;font-size:13px;line-height:1.5}
.warnbar b{color:var(--warn)}
.warnbar button{position:absolute;right:10px;top:8px;width:26px;height:26px;
  border-radius:7px;color:var(--dim);font-size:14px}
.warnbar button:hover{background:rgba(255,176,32,.2);color:var(--txt)}

/* ---------- private owner panel ---------- */
.owner{border-top:1px solid var(--line);margin-top:6px;padding-top:12px}
.owner-row{display:flex;gap:10px;margin-bottom:10px}
.owner-row>div{flex:1;background:var(--card2);border-radius:10px;padding:9px 11px}
.owner-row b{display:block;font-size:19px;font-weight:750;letter-spacing:-.5px}
.owner-row span{font-size:10.5px;color:var(--dim2);text-transform:uppercase;letter-spacing:.5px}
.owner .spark{height:38px;margin-bottom:9px}
.owner code{background:var(--card);padding:1px 5px;border-radius:5px;font-size:11.5px}

/* ---------- reference sheets ---------- */
.ref-card{background:var(--card);border:1px solid var(--line);border-radius:var(--r);
  padding:17px;margin-bottom:12px}
.ref-card>h2{font-size:16px;font-weight:650;display:flex;align-items:center;gap:9px}
.ref-card>p{font-size:12.5px;color:var(--dim);margin:4px 0 0}
.ref-sec{margin-top:15px}
.ref-sec h4{font-size:11.5px;font-weight:700;color:var(--acc2);text-transform:uppercase;
  letter-spacing:.6px;margin-bottom:7px}
.ref-row{display:flex;gap:14px;padding:7px 0;border-bottom:1px solid var(--line);font-size:13.5px}
.ref-row:last-child{border-bottom:none}
.ref-row .k{flex:0 0 172px;color:var(--dim);font-weight:500}
.ref-row .v{flex:1;min-width:0}
.tex-raw{font-family:ui-monospace,Menlo,Consolas,monospace;font-size:.95em;
  background:var(--card2);padding:1px 5px;border-radius:5px}

/* ---------- lesson mode ---------- */
.lesson{padding:22px 24px}
.lesson-idea{font-size:16px;font-weight:550;line-height:1.55;padding-bottom:15px;
  margin-bottom:15px;border-bottom:1px solid var(--line)}
.lesson-points{display:flex;flex-direction:column;gap:11px}
.lesson-point{display:flex;gap:11px;font-size:14px;line-height:1.55}
.lesson-point .dot{flex:0 0 7px;height:7px;border-radius:50%;background:var(--acc);margin-top:8px}
.lesson-ex{margin-top:20px;padding:15px 17px;border-radius:12px;background:var(--card2)}
.lesson-ex h4{font-size:11px;font-weight:700;color:var(--acc2);text-transform:uppercase;
  letter-spacing:.6px;margin-bottom:9px}
.lesson-ex .exq{font-size:14.5px;font-weight:500;margin-bottom:11px}
.lesson-ex .exs{display:flex;gap:10px;font-size:13.5px;padding:4px 0;color:var(--dim)}
.lesson-ex .exs b{flex:0 0 19px;height:19px;border-radius:50%;background:var(--acc);
  color:#fff;font-size:11px;display:grid;place-items:center;margin-top:2px}

/* ---------- study plan ---------- */
.dateinp{padding:9px 12px;border-radius:10px;background:var(--card2);border:1px solid var(--line);
  color:var(--txt);font-family:inherit;font-size:13.5px;color-scheme:dark}
[data-theme="light"] .dateinp{color-scheme:light}
.weekrow{display:flex;align-items:center;gap:14px;padding:12px 0;border-bottom:1px solid var(--line)}
.weekrow:last-child{border-bottom:none}
.weekrow.now{background:linear-gradient(90deg,rgba(124,92,255,.10),transparent);
  margin:0 -8px;padding-left:8px;padding-right:8px;border-radius:9px}
.weekrow .wk{flex:0 0 96px}
.weekrow .wk b{display:block;font-size:13.5px}
.weekrow .wk span{font-size:11.5px;color:var(--dim2)}
.weekrow .wf{flex:1;min-width:0}
.weekrow .wf b{display:block;font-size:14px;font-weight:600}
.weekrow .wf span{font-size:12.5px;color:var(--dim)}

/* ---------- responsive ---------- */
@media(max-width:1000px){.g4{grid-template-columns:repeat(2,1fr)}.g3{grid-template-columns:repeat(2,1fr)}}
@media(max-width:820px){
  .app{flex-direction:column}
  .side{width:100%;flex:none;height:auto;position:static;flex-direction:row;
    align-items:center;gap:4px;padding:10px;overflow-x:auto;border-right:none;border-bottom:1px solid var(--line)}
  .brand{padding:0 12px 0 4px;flex:0 0 auto}
  .brand .txt{display:none}
  .nav{flex-direction:row;gap:4px}
  .nav button{padding:8px 12px;white-space:nowrap;font-size:13px}
  .nav button .lb{display:none}
  .nav .ic{font-size:17px}
  .side-foot{display:none}
  .main{padding:18px 16px 60px}
  .g4,.g3,.g2{grid-template-columns:1fr 1fr}
  .trow .nm{flex:0 0 120px}
}
@media(max-width:820px){
  .ref-row{flex-direction:column;gap:3px}
  .ref-row .k{flex:none}
}
@media(max-width:520px){
  .g4,.g3,.g2{grid-template-columns:1fr}
  .fc-rate{grid-template-columns:repeat(2,1fr)}
  .head h1{font-size:21px}
  .fab{right:16px;bottom:16px;width:52px;height:52px}
  .fab .fab-ic{font-size:21px}
  .coach-overlay{right:10px;left:10px;width:auto;bottom:78px;
    max-height:calc(100vh - 110px)}
}