:root{
    --bg:#f6f7fb; --panel:#ffffff; --ink:#1f2937; --muted:#6b7280; --line:#e5e7eb;
    --accent:#2563eb; --accent2:#f59e0b; --ok:#059669; --warn:#b91c1c;
  }
  *{box-sizing:border-box}
  [hidden]{display:none!important}
  body{margin:0;font-family:system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;background:var(--bg);color:var(--ink);font-size:15px;line-height:1.5}
  header{background:#111827;color:#fff;padding:12px 20px;display:flex;flex-wrap:wrap;gap:16px;align-items:center;justify-content:space-between}
  header h1{margin:0;font-size:18px;font-weight:600}
  .conv{background:#1f2937;border:1px solid #374151;border-radius:8px;padding:6px 12px;font-size:13px;display:flex;gap:14px;align-items:center;flex-wrap:wrap}
  .conv b{color:#fbbf24}
  .app{display:flex;min-height:calc(100vh - 56px)}
  nav{width:230px;flex:none;background:var(--panel);border-right:1px solid var(--line);padding:14px 10px;position:sticky;top:0;height:calc(100vh - 56px);overflow:auto}
  nav button{display:block;width:100%;text-align:left;background:none;border:1px solid transparent;border-radius:8px;padding:9px 12px;margin-bottom:4px;cursor:pointer;color:var(--ink);font-size:14px}
  nav button small{display:block;color:var(--muted);font-size:12px}
  nav button:hover{background:#eef2ff}
  nav button.active{background:#dbeafe;border-color:#93c5fd;font-weight:600}
  nav button.todo{opacity:.65}
  main{flex:1;padding:20px 28px;max-width:1280px}
  .mod{display:none}
  .mod.active{display:block}
  h2{margin:0 0 6px;font-size:22px}
  h3{margin:24px 0 10px;font-size:16px;color:#111827}
  h3:first-child{margin-top:0}
  .lead{color:var(--muted);margin:0 0 20px}
  .grid{display:grid;grid-template-columns:minmax(380px,600px) 1fr;gap:26px;align-items:start}
  /* abaixo de 1200px a coluna da esquerda toma quase tudo e a das fórmulas fica espremida:
     uma coluna só, desenho em cima e fórmulas embaixo */
  @media(max-width:1200px){.grid{grid-template-columns:1fr}}
  .card{background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:18px 20px;margin-bottom:20px}
  canvas{display:block;max-width:100%;border-radius:10px;background:#fff;touch-action:none}
  .c3d{border:1px solid var(--line);cursor:grab}
  .ctrl{display:grid;grid-template-columns:1fr auto;grid-auto-flow:row dense;gap:0 12px;margin-top:6px;font-size:14px}
  .ctrl label{grid-column:1;align-self:end;padding-top:10px;color:var(--muted);font-size:13px}
  .ctrl output{grid-column:2;align-self:end;padding-top:10px;font-variant-numeric:tabular-nums;text-align:right;font-weight:600;white-space:nowrap}
  .ctrl input[type=range]{grid-column:1/-1}
  input[type=range]{width:100%}
  .row{display:flex;gap:10px;flex-wrap:wrap;align-items:center;margin-top:10px;font-size:14px}
  .btn{background:var(--accent);color:#fff;border:none;border-radius:8px;padding:7px 14px;cursor:pointer;font-size:14px}
  .btn.sec{background:#e5e7eb;color:var(--ink)}
  .btn:disabled{opacity:.4;cursor:default}
  .btn.sys,.btn.sys1,.btn.sym1,.btn.typ3,.btn.con5{background:#e5e7eb;color:var(--ink)}
  .btn.sys.active,.btn.sys1.active,.btn.sym1.active,.btn.typ3.active,.btn.con5.active{background:var(--accent);color:#fff}
  .fx.pick{--fxbg:#fffbeb;border-color:#fcd34d}
  .fx{margin:12px 0;padding:10px 12px;--fxbg:#f9fafb;background:var(--fxbg);border:1px solid var(--line);border-radius:8px;overflow-x:auto}
  .fx.hl{--fxbg:#fffbeb;border-color:#fcd34d}
  .fx.res{--fxbg:#ecfdf5;border-color:#6ee7b7}
  .note{font-size:13px;color:var(--muted)}
  .tag{display:inline-block;font-size:12px;padding:2px 8px;border-radius:999px;background:#e5e7eb;color:#374151;margin-left:6px;vertical-align:middle}
  .tag.in{background:#fef3c7;color:#92400e}
  .tag.out{background:#dbeafe;color:#1e40af}
  .legend{display:flex;gap:14px;flex-wrap:wrap;font-size:13px;margin-top:8px;color:var(--muted)}
  .legend span::before{content:"";display:inline-block;width:12px;height:12px;border-radius:3px;margin-right:5px;vertical-align:-1px;background:var(--c)}
  .num{display:grid;grid-template-columns:auto 1fr;gap:4px 14px;font-size:14px;font-variant-numeric:tabular-nums}
  .num b{font-weight:600}
  .steps{display:flex;gap:6px;margin:8px 0}
  .steps i{flex:1;height:6px;border-radius:3px;background:#e5e7eb;font-style:normal}
  .steps i.on{background:var(--accent)}
  .todo-list{margin:0;padding-left:20px}
  .todo-list li{margin:4px 0}
  .katex-display{margin:4px 0}

/* ---------- casca compartilhada, toque e passos ---------- */
.btn{min-height:44px;padding:8px 16px}
.btn.pk{min-height:40px;padding:6px 12px}
.btn.pk.active{background:#db2777;color:#fff}
input[type=range]{width:100%;height:44px;margin:0;-webkit-appearance:none;appearance:none;background:transparent;cursor:pointer}
input[type=range]::-webkit-slider-runnable-track{height:6px;background:#d1d5db;border-radius:3px}
input[type=range]::-webkit-slider-thumb{-webkit-appearance:none;width:28px;height:28px;border-radius:50%;background:var(--accent);margin-top:-11px;border:2px solid #fff;box-shadow:0 1px 3px rgba(0,0,0,.3)}
input[type=range]::-moz-range-track{height:6px;background:#d1d5db;border-radius:3px}
input[type=range]::-moz-range-thumb{width:28px;height:28px;border-radius:50%;background:var(--accent);border:2px solid #fff}
input[type=checkbox],input[type=radio]{width:22px;height:22px;vertical-align:middle}
label{cursor:pointer}
:focus-visible{outline:3px solid #f59e0b;outline-offset:2px}
.picks{align-items:center}
.fx.linkable{cursor:pointer}
.fx.linkable:hover{border-color:#a5b4fc}
.fx.new{border-color:#f97316;--fxbg:#fff7ed;box-shadow:0 0 0 2px #fed7aa inset}
.fx.old{opacity:.8}
.fx.pick{border-color:#db2777;--fxbg:#fdf2f8;box-shadow:0 0 0 2px #fbcfe8 inset;opacity:1}
.why{background:#f0fdf4;border-left:4px solid #059669;padding:8px 12px;border-radius:6px;font-size:14px;margin:0 0 10px}
.timeline{position:sticky;bottom:0;z-index:5;background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:10px 14px;margin-top:14px;display:flex;gap:10px;align-items:center;flex-wrap:wrap;box-shadow:0 -2px 10px rgba(0,0,0,.06)}
.timeline input[type=range]{flex:1;min-width:140px}
.timeline .tl-title{flex-basis:100%;font-weight:600;font-size:14px}
.katex-display{overflow-x:auto;overflow-y:hidden;padding:2px 0}
.fx .katex{font-size:1.05em}
canvas.graph{max-width:100%}
@media(max-width:1000px){
  .app{flex-direction:column}
  main{padding:14px}
  header{padding:10px 14px}
  .conv{font-size:12px}
  .fx .katex{font-size:0.95em}
}
.card.new{border-color:#f97316;box-shadow:0 0 0 2px #fed7aa inset}
.btn.kind,.btn.prof,.btn.geo{background:#e5e7eb;color:var(--ink)}
.btn.kind.active,.btn.prof.active,.btn.geo.active{background:var(--accent);color:#fff}
table.cmp{border-collapse:collapse;font-size:13px;margin:8px 0;min-width:640px}
table.cmp th,table.cmp td{border:1px solid var(--line);padding:6px 8px;text-align:left;vertical-align:top}
table.cmp th{background:#f3f4f6}
/* ---------- PWA: avisos ---------- */
.toast{position:fixed;right:16px;bottom:16px;z-index:50;background:#111827;color:#fff;padding:12px 16px;border-radius:12px;box-shadow:0 6px 24px rgba(0,0,0,.35);display:flex;gap:12px;align-items:center;font-size:14px;max-width:calc(100vw - 32px)}
.toast .btn{background:#f59e0b;color:#111827;font-weight:600}
/* ---------- trilha de estudo e navegação por partes ---------- */
/* cabeçalho de parte: botão que recolhe e expande a lista de módulos daquela parte */
nav .navh{display:flex;align-items:center;gap:6px;width:100%;text-align:left;background:none;border:none;cursor:pointer;
  font-size:11px;letter-spacing:.06em;text-transform:uppercase;color:var(--muted);margin:14px 0 4px;padding:10px 10px 6px;border-top:1px solid var(--line)}
nav .navh:hover{color:var(--ink)}
nav .navh .chev{display:inline-block;width:10px;flex:none;font-size:10px;color:var(--muted)}
nav .navh .chev::before{content:"\25BE"}
nav .navh.collapsed .chev::before{content:"\25B8"}
nav .navpart:first-of-type .navh{border-top:none;margin-top:4px}
.navtoggle{display:none;align-items:center;gap:10px;width:100%;min-height:44px;background:#fff;border:1px solid var(--line);border-radius:10px;
  padding:8px 12px;font-size:15px;color:var(--ink);cursor:pointer;text-align:left}
.navtoggle .bars{font-size:18px;line-height:1}
.navtoggle .navnow{font-weight:600;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
nav button .code{display:inline-block;min-width:34px;font-size:11px;font-weight:700;color:#6b7280;margin-right:4px;font-variant-numeric:tabular-nums}
nav button.active .code{color:var(--accent)}
nav button small{font-size:11px}
.crumb{font-size:12px;letter-spacing:.05em;text-transform:uppercase;color:var(--muted);margin-bottom:4px}
.modnav{display:flex;gap:10px;justify-content:space-between;flex-wrap:wrap;margin-top:22px;padding-top:14px;border-top:1px solid var(--line)}
.modnav .btn{max-width:48%;text-align:left}
.card.part h3{display:flex;align-items:center;gap:10px;margin-top:0}
.card.part .pn{display:inline-flex;width:28px;height:28px;border-radius:50%;background:var(--accent);color:#fff;align-items:center;justify-content:center;font-size:14px}
.plist{display:flex;flex-direction:column;gap:6px;margin-top:8px}
.prow{display:grid;grid-template-columns:44px 1fr;gap:2px 10px;text-align:left;background:#f9fafb;border:1px solid var(--line);border-radius:10px;padding:10px 12px;cursor:pointer;font:inherit;color:var(--ink);min-height:44px}
.prow:hover{background:#eef2ff;border-color:#c7d2fe}
.prow .code{font-weight:700;color:var(--accent);grid-row:1/3;align-self:start;padding-top:2px}
.prow .pt{font-weight:600}
.prow .pd{font-size:13px;color:var(--muted)}
.prow .tag{font-size:11px;padding:1px 7px;margin-left:6px;font-style:normal}
@media(max-width:1000px){ nav button .code{min-width:auto} }
/* ---------- celular e tablet em retrato: menu recolhido atrás do ☰ ---------- */
@media(max-width:1000px){
  nav{display:block;width:100%;height:auto;position:sticky;top:0;z-index:20;padding:8px 10px;overflow:visible;border-right:none;border-bottom:1px solid var(--line)}
  .navtoggle{display:flex}
  .navlist{display:none}
  nav.open .navlist{display:block;max-height:70vh;overflow:auto;margin-top:8px;padding-top:4px;border-top:1px solid var(--line)}
  nav button small{display:none}
  main{padding:10px}
  .card{padding:14px 14px}
  h2{font-size:20px}
  .lead{font-size:14px}
  input[type=range]{min-width:0}
  .toast{left:12px;right:12px;bottom:64px;justify-content:space-between}
  .modnav .btn{max-width:100%}
  header{gap:8px}
}
nav .navg{font-size:11px;color:var(--muted);margin:8px 12px 2px;font-style:italic}
.gtitle{font-size:12px;letter-spacing:.04em;text-transform:uppercase;color:var(--muted);margin:12px 0 4px}

/* colunas do grid podem encolher abaixo do conteudo: o canvas (max-width:100%) e as formulas (.fx com scroll) se ajustam a tela em vez de alargar a pagina */
.grid>*{min-width:0}

/* ---------- indicacao de conteudo cortado nas formulas largas ----------
   Sombra na borda enquanto houver conteudo escondido daquele lado; some ao chegar no fim.
   As duas primeiras camadas (fundo, "local") rolam com o conteudo e cobrem as sombras nas pontas;
   as duas ultimas (sombras, "scroll") ficam presas a caixa. Vale para a caixa .fx, para o
   .katex-display dentro dela (que e quem rola de fato) e para a linha da convencao no cabecalho. */
.fx, .fx .katex-display, .conv > span{
  --sh:rgba(17,24,39,.32);
  background:
    linear-gradient(90deg, var(--fxbg) 45%, rgba(255,255,255,0)) left/48px 100% no-repeat local,
    linear-gradient(270deg, var(--fxbg) 45%, rgba(255,255,255,0)) right/48px 100% no-repeat local,
    radial-gradient(farthest-side at 0 50%, var(--sh), rgba(0,0,0,0)) left/18px 100% no-repeat scroll,
    radial-gradient(farthest-side at 100% 50%, var(--sh), rgba(0,0,0,0)) right/18px 100% no-repeat scroll,
    var(--fxbg);
}
.fx .katex-display{margin:4px 0;padding:2px 0}
.conv > span{--fxbg:#1f2937;--sh:rgba(255,255,255,.55);display:block;min-width:0;max-width:100%;overflow-x:auto;padding:2px 0}

/* ---------- resolver na mao: passo a passo das integrais ---------- */
.hand{margin:2px 0 12px}
.hand-btn{font-size:13px;padding:5px 12px;border:1px dashed #a5b4fc;background:#eef2ff;color:#3730a3}
.hand-panel{margin-top:8px;padding:10px 12px;border:1px dashed #a5b4fc;border-radius:8px;background:#fff}
.hand-head{display:flex;flex-wrap:wrap;gap:6px 10px;align-items:center;margin-bottom:4px}
.hand-tech{margin-left:0;background:#e0e7ff;color:#3730a3}
.hand-xref{font-size:13px;color:var(--muted)}
.hand-title{font-weight:600;font-size:14px;margin:8px 0 2px}
.hand-steps i.chk.on{background:#059669}
.hand-what,.hand-why{margin:6px 0}
.hand-nav{margin-top:6px}
.hand-count{margin-left:auto;font-size:13px;color:var(--muted);font-variant-numeric:tabular-nums}

/* ---------- modo de prática ---------- */
.mp-q{font-size:14px;margin:4px 0 8px}
.mp-opts{display:flex;flex-wrap:wrap;gap:8px}
.mp-opts .btn{min-height:44px;text-align:left}
.mp-opts .btn.chosen{outline:2px solid #6366f1;outline-offset:1px}
.mp-opts .btn.right{background:#d1fae5;color:#065f46}
.mp-opts .btn:disabled{opacity:.75;cursor:default}
.mp-fb{margin-top:10px;padding:10px 12px;border-radius:8px;font-size:14px;line-height:1.45}
.mp-fb.ok{background:#ecfdf5;border:1px solid #6ee7b7}
.mp-fb.err{background:#fef2f2;border:1px solid #fca5a5}

/* ---------- largura de leitura e respiro ----------
   Linha longa demais cansa: os parágrafos param em 72 caracteres, mesmo em tela larga.
   O desenho e as fórmulas ganham margem para não encostarem no texto. */
.lead, .mod p, .num > span{max-width:72ch}
.card canvas{margin-bottom:12px}
.card > .row:first-child{margin-top:0}
.legend{margin-top:10px;gap:16px}
.ctrl{margin-top:10px}
.num{gap:6px 16px}

/* ---------- linha do slider: ajuste fino e valor digitado ---------- */
.srow{display:flex;align-items:center;gap:8px}
.ctrl .srow{grid-column:1/-1}
.timeline .srow{flex:1;min-width:140px}
.srow input[type=range]{flex:1;min-width:0}
.sbtn{flex:none;width:38px;height:38px;border:1px solid var(--line);background:#f3f4f6;color:var(--ink);
  border-radius:9px;font:inherit;font-size:18px;line-height:1;cursor:pointer}
.sbtn:hover{background:#e5e7eb}
.sbtn:active{background:#d1d5db}
.sedit{flex:none;width:100px;min-height:38px;border:1px solid var(--accent);border-radius:8px;padding:4px 8px;font:inherit;font-size:14px;text-align:right}
.onum{cursor:pointer;border-radius:6px}
.onum:hover{background:#eef2ff;box-shadow:0 0 0 3px #eef2ff}
.onum.snap{animation:snapflash .9s ease-out}
@keyframes snapflash{0%{background:#fde68a;box-shadow:0 0 0 3px #fde68a}100%{background:transparent;box-shadow:0 0 0 3px transparent}}

/* ---------- destaque do termo novo ao avançar um passo ---------- */
@keyframes fxflash{
  0%{box-shadow:0 0 0 3px #fcd34d, inset 0 0 0 2px #fbbf24}
  100%{box-shadow:0 0 0 3px rgba(252,211,77,0), inset 0 0 0 2px rgba(251,191,36,0)}
}
.fx.flash{animation:fxflash 2s ease-out}
@media(prefers-reduced-motion:reduce){ .fx.flash{animation:none} }

/* ---------- listas: sequências saem do parágrafo ---------- */
.lista{max-width:72ch;margin:0 0 18px;padding-left:24px}
.lista li{margin:5px 0}
.lead + .lista{margin-top:-10px}
.note + .lista{margin-top:-6px}
ol.lista li::marker{font-weight:600;color:var(--accent)}

/* ---------- índice de exercícios ---------- */
.exrow{display:grid;grid-template-columns:52px 1fr auto;gap:4px 14px;align-items:start;
  background:var(--panel);border:1px solid var(--line);border-radius:10px;padding:12px 14px;margin-bottom:8px}
.exrow.papel{background:#fafafa;border-style:dashed}
.exn{font-weight:700;color:var(--accent);font-variant-numeric:tabular-nums}
.exrow.papel .exn{color:var(--muted)}
.exmid{min-width:0}
.ext{margin:0;max-width:72ch}
.exloc{margin:3px 0 0;font-size:13px;color:var(--muted)}
.exfonte{color:#9ca3af}
.exobs{margin:5px 0 0;font-size:13px;color:#92400e;background:#fffbeb;border-left:3px solid #fcd34d;padding:5px 9px;border-radius:5px;max-width:72ch}
.exgo{align-self:center}
.exgo .btn{min-height:40px;padding:6px 14px}
@media(max-width:1000px){
  .exrow{grid-template-columns:44px 1fr;gap:4px 10px}
  .exgo{grid-column:1/-1;align-self:start;margin-top:6px}
  .exgo .btn{width:100%}
}