@font-face{font-family:"Rubik";font-style:normal;font-weight:400 700;font-display:swap;src:url(fonts/rubik-hebrew.woff2) format("woff2");unicode-range:U+0307-0308,U+0590-05FF,U+200C-2010,U+20AA,U+25CC,U+FB1D-FB4F}
@font-face{font-family:"Rubik";font-style:normal;font-weight:400 700;font-display:swap;src:url(fonts/rubik-latin.woff2) format("woff2");unicode-range:U+0000-00FF,U+0131,U+0152-0153,U+02BB-02BC,U+02C6,U+02DA,U+02DC,U+2000-206F,U+20AC,U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD}
:root{--bg:#fff9f2;--card:#fff;--ink:#23213a;--mute:#5d5a72;--line:#ece4d8;--acc:#4338ca;--acc-d:#3730a3;--acc2:#eef0ff;--warm:#f59e0b;--fin:#fff6dc;--finl:#e0a100;--ok:#15803d;--okl:#e6f6ec;--rev:#c2410c;--revl:#fff0e5;--r:16px;--sh:0 1px 2px rgba(60,40,20,.05),0 6px 18px rgba(60,40,20,.07)}
.t-linear-programming{--tc:#0f766e;--tl:#e0f4f1}
.t-analytic-geometry{--tc:#6d28d9;--tl:#f1eafe}
.t-normal-distribution{--tc:#c2410c;--tl:#fff0e4}
.t-quadratic-model{--tc:#be185d;--tl:#fde8f1}
.t-spatial-vision{--tc:#1d4ed8;--tl:#e7eefe}
.t-solids{--tc:#15803d;--tl:#e5f5e9}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);font-family:"Rubik","Assistant","Segoe UI","Arial Hebrew",Arial,sans-serif;font-size:17px;line-height:1.7}
a{color:var(--acc)}
a:focus-visible,summary:focus-visible,.bigbtn:focus-visible,.tile:focus-visible,.mk:focus-visible,.restile:focus-visible{outline:3px solid var(--warm);outline-offset:2px;border-radius:8px}
.wrap{max-width:880px;margin:0 auto;padding:0 16px}
.skip{position:absolute;right:-999px;top:0;background:#fff;padding:8px;z-index:20}
.skip:focus{right:8px}
/* header */
.top{background:linear-gradient(120deg,#3730a3 0%,#5b21b6 55%,#9d174d 100%);color:#fff;position:relative;box-shadow:0 2px 10px rgba(55,48,163,.25)}
.bsd{position:absolute;top:4px;right:10px;font-size:12px;line-height:1;font-weight:500;color:#fff;opacity:.95;letter-spacing:.5px}
.top .wrap{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:6px 16px;padding-top:20px;padding-bottom:10px}
.brand{display:flex;align-items:center;gap:8px;font-weight:700;text-decoration:none;color:#fff;font-size:16px;line-height:1.3}
.brand .logo{flex:none;width:30px;height:30px;border-radius:9px;background:rgba(255,255,255,.18);display:grid;place-items:center}
.topnav{display:flex;flex-wrap:wrap;gap:4px 6px;font-size:15px}
.topnav a{text-decoration:none;font-weight:600;color:#fff;padding:3px 10px;border-radius:999px;background:rgba(255,255,255,.12)}
.topnav a:hover{background:rgba(255,255,255,.25)}
main{padding-top:20px;padding-bottom:44px}
h1{font-size:27px;line-height:1.3;margin:8px 0 8px;font-weight:700}
h2{font-size:21px;line-height:1.35}
/* home */
.hero{margin:6px 0 4px;padding:26px 20px 24px;text-align:center;border-radius:22px;background:radial-gradient(circle at 12% 20%,#ffe3b3 0,transparent 42%),radial-gradient(circle at 88% 85%,#ffd1e3 0,transparent 45%),linear-gradient(160deg,#fff 0%,#fff4e6 100%);border:1px solid var(--line);box-shadow:var(--sh)}
.hero h1{font-size:28px;margin:6px 0 6px}
.hero .kicker{display:inline-block;background:var(--acc2);color:var(--acc);font-weight:700;font-size:14px;padding:3px 12px;border-radius:999px}
.sub,.lead{color:var(--mute);margin-top:0}
.choose{display:grid;grid-template-columns:1fr;gap:14px;margin:20px 0}
@media(min-width:640px){.choose{grid-template-columns:1fr 1fr}}
.bigbtn{display:flex;align-items:center;gap:14px;color:#fff;text-decoration:none;border-radius:20px;padding:20px 18px;box-shadow:0 8px 22px rgba(67,56,202,.25);background:linear-gradient(135deg,#4338ca,#6d28d9);transition:transform .15s}
.bigbtn:nth-child(2){background:linear-gradient(135deg,#db2777,#f59e0b);box-shadow:0 8px 22px rgba(219,39,119,.22)}
.bigbtn:hover{transform:translateY(-2px)}
.bigbtn .bi{flex:none;width:52px;height:52px;border-radius:16px;background:rgba(255,255,255,.2);display:grid;place-items:center}
.bigbtn .bt{display:block;font-size:24px;font-weight:700;line-height:1.25}
.bigbtn .bs{display:block;opacity:.95;font-size:15px;margin-top:2px;line-height:1.45}
.how{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:6px 18px 10px;box-shadow:var(--sh)}
.how h2{margin:12px 0 4px}
.how ol{padding-inline-start:22px}
.how li{margin:4px 0}
.stats{color:var(--mute);font-size:15px}
.homechips{list-style:none;padding:0;margin:0 0 18px;display:grid;grid-template-columns:1fr 1fr;gap:10px}
@media(min-width:640px){.homechips{grid-template-columns:1fr 1fr 1fr}}
.homechips a{display:flex;align-items:center;gap:8px;background:var(--tl);color:var(--tc);border-radius:14px;padding:10px 12px;text-decoration:none;font-weight:700;font-size:15px;line-height:1.3;border:1px solid transparent}
.homechips a:hover{border-color:var(--tc)}
.homechips .ic{width:30px;height:30px;border-radius:9px}
.sech{font-size:19px;margin:22px 0 10px}
/* icons */
.ic{flex:none;display:grid;place-items:center;width:46px;height:46px;border-radius:14px;background:var(--tc);color:#fff}
.ic svg{width:62%;height:62%}
/* tiles */
.tiles{list-style:none;padding:0;margin:0 0 18px;display:grid;grid-template-columns:1fr;gap:12px}
@media(min-width:640px){.tiles{grid-template-columns:1fr 1fr}}
.tile{display:flex;gap:12px;align-items:center;background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:14px 14px;text-decoration:none;color:var(--ink);box-shadow:var(--sh);transition:transform .15s,border-color .15s;height:100%}
.tile:hover{transform:translateY(-2px);border-color:var(--tc,var(--acc))}
.tile.topic{border-inline-start:6px solid var(--tc)}
.tbody{flex:1;min-width:0;display:flex;flex-direction:column}
.tt{font-weight:700;font-size:18px;line-height:1.35}
.tn{color:var(--mute);font-size:14px}
.tprog{font-size:13px;color:var(--mute);margin-top:4px}
.tprog:empty{display:none}
.bar{display:block;height:6px;border-radius:99px;background:#efe8dc;overflow:hidden;margin-top:5px}
.bar i{display:block;height:100%;background:linear-gradient(90deg,#16a34a,#22c55e);border-radius:99px;width:0;transition:width .3s}
.season{--tc:#1d4ed8;--tl:#e7eefe}
.season.summer{--tc:#d97706;--tl:#fff3dc}
.season.special{--tc:#7c3aed;--tl:#f1eafe}
.tile.season .ic{background:var(--tl);color:var(--tc)}
.yr{margin:22px 0 10px;color:var(--ink);font-size:20px;display:flex;align-items:center;gap:10px}
.yr::after{content:"";flex:1;height:2px;background:var(--line);border-radius:2px}
.crumbs{margin:0;font-size:14px}
/* topic page head */
.phead{display:flex;gap:14px;align-items:center;background:var(--tl,var(--acc2));border-radius:20px;padding:16px;margin:6px 0 14px}
.phead .ic{width:56px;height:56px;border-radius:16px}
.phead h1{margin:0;color:var(--tc,var(--ink))}
.phead .lead{margin:2px 0 0}
.season.phead .ic{background:var(--tc);color:#fff}
.progress{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:10px 14px;margin:0 0 16px;font-size:15px;box-shadow:var(--sh)}
.progress b{color:var(--ok)}
.progress .rv{color:var(--rev);font-weight:700}
.progress a{font-size:14px;white-space:nowrap}
.progress .prow{display:flex;flex-wrap:wrap;justify-content:space-between;gap:2px 12px;align-items:baseline}
/* bottom question menu */
.toc{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:12px 14px 14px;margin:26px 0 8px;box-shadow:var(--sh);scroll-margin-top:10px}
.toc h2{margin:0 0 4px;font-size:19px}
.toc .legend{margin:0 0 10px;font-size:13px;color:var(--mute)}
.toc ul{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:1fr;gap:6px}
@media(min-width:640px){.toc ul{grid-template-columns:1fr 1fr}}
.toc li a{display:flex;align-items:center;gap:10px;padding:8px 10px;border-radius:10px;background:#faf6ef;text-decoration:none;color:var(--ink);font-size:15px;line-height:1.35;border:1px solid transparent;min-height:44px}
.toc li a:hover{border-color:var(--acc)}
.st{flex:none;width:24px;height:24px;border-radius:50%;border:2px solid #cfc6b8;background:#fff;display:grid;place-items:center;font-size:13px;font-weight:700;color:#fff;line-height:1}
.toc li.done a{background:var(--okl)}
.toc li.done .st{background:var(--ok);border-color:var(--ok)}
.toc li.done .st::after{content:"✓"}
.toc li.review a{background:var(--revl)}
.toc li.review .st{background:var(--rev);border-color:var(--rev)}
.toc li.review .st::after{content:"↺"}
.tdot{flex:none;width:10px;height:10px;border-radius:50%;background:var(--tc)}
.ltxt{flex:1}
.lmk{font-size:12px;font-weight:700;white-space:nowrap}
.toc li.done .lmk{color:var(--ok)}
.toc li.review .lmk{color:var(--rev)}
.totop{display:inline-block;margin-top:10px;font-size:14px}
/* question card */
.q{background:var(--card);border:1px solid var(--line);border-top:6px solid var(--tc,var(--acc));border-radius:var(--r);padding:14px 14px 12px;margin:0 0 22px;scroll-margin-top:12px;box-shadow:var(--sh)}
.q.is-done{border-color:#b7e2c4;border-top-color:var(--ok)}
.q.is-review{border-color:#f5cfb3;border-top-color:var(--rev)}
.qh{display:flex;flex-wrap:wrap;justify-content:space-between;align-items:center;gap:4px 12px}
.qh h3{margin:0;font-size:20px;line-height:1.35}
.qmeta{margin:0;font-size:14px}
.chip{display:inline-flex;align-items:center;gap:6px;background:var(--tl);color:var(--tc);border-radius:999px;padding:2px 10px 2px 4px;text-decoration:none;font-weight:600;font-size:14px}
.chip .ic{width:22px;height:22px;border-radius:50%}
.qstat{display:none;font-size:13px;font-weight:700;border-radius:999px;padding:1px 10px}
.q.is-done .qstat.d{display:inline-block;background:var(--okl);color:var(--ok)}
.q.is-review .qstat.r{display:inline-block;background:var(--revl);color:var(--rev)}
.qimg{margin:12px 0 6px}
.qimg img{display:block;width:100%;height:auto;border:1px solid var(--line);border-radius:10px;background:#fff;margin-bottom:6px}
.qimg figcaption{font-size:13px}
.sols{margin-top:8px}
details.sol{border:1px solid var(--line);border-radius:10px;margin:8px 0;background:#fbfcfc}
details.sol>summary{cursor:pointer;list-style:none;padding:11px 14px;font-weight:700;color:var(--acc);background:var(--acc2);border-radius:10px;min-height:44px;display:flex;align-items:center}
details.sol>summary::-webkit-details-marker{display:none}
.solbody{padding:6px 14px 10px;overflow-x:auto}
.solbody p{margin:8px 0}
.solbody ul,.solbody ol{padding-inline-start:20px}
.solbody table{border-collapse:collapse;margin:8px 0;font-size:15px}
.solbody td,.solbody th{border:1px solid var(--line);padding:4px 8px;text-align:center}
.mathd{text-align:center;margin:10px 0;padding:2px 0;overflow-x:auto;overflow-y:hidden;line-height:2.1}
.math{unicode-bidi:isolate}
.katex{font-size:1.05em}
.final{background:var(--fin);border-inline-start:4px solid var(--finl);padding:8px 12px;border-radius:8px;font-weight:600}
.finlbl{color:#8a5a00}
.note{color:var(--mute);font-size:14px}
.solbody>img,.solbody>p>img{max-width:100%;height:auto}
.katex svg{max-width:none}
.qfoot{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:8px 12px;margin-top:10px;padding-top:10px;border-top:1px dashed var(--line)}
.video{margin:0;font-size:15px}
.video.soon{color:var(--mute)}
/* mark buttons */
.marks{display:flex;flex-wrap:wrap;gap:8px;margin-top:10px}
.marks[hidden]{display:none}
.mk{flex:1 1 150px;min-height:44px;display:flex;align-items:center;justify-content:center;gap:6px;border-radius:999px;border:2px solid;background:#fff;font:inherit;font-size:15px;font-weight:700;cursor:pointer;padding:6px 12px}
.mk.d{border-color:#9fd6b0;color:var(--ok)}
.mk.r{border-color:#f3c09c;color:var(--rev)}
.mk.d[aria-pressed="true"]{background:var(--ok);border-color:var(--ok);color:#fff}
.mk.r[aria-pressed="true"]{background:var(--rev);border-color:var(--rev);color:#fff}
.mkhint{width:100%;margin:0;font-size:13px;color:var(--mute)}
.foot{border-top:1px solid var(--line);color:var(--mute);font-size:14px;padding:12px 0 26px;background:#fff}
.foot .credit{font-weight:700;color:var(--ink)}
@media print{.top,.foot,.video,.marks,.toc,.progress{display:none}details.sol{break-inside:avoid}}

.gridwrap{display:inline-block;margin:6px 10px;vertical-align:top;text-align:center}
table.numgrid{border-collapse:collapse;margin:0 auto}
table.numgrid td{border:1.5px solid #333;width:34px;height:34px;text-align:center;font-weight:700;font-size:17px;padding:0}
table.numgrid td.hl{background:#fde68a}
table.view{border-collapse:collapse;margin:0 auto}
table.view td{width:26px;height:26px;padding:0;border:1px solid #c8d0ce}
table.view td.f{background:#9cc3c5;border:1.5px solid #234}
.gcap{margin:4px 0 0;font-size:14px;color:var(--mute)}
.solimg{display:block;max-width:100%;height:auto;margin:8px auto;border:1px solid var(--line);border-radius:6px;background:#fff}
.solbody table{display:block;max-width:100%;overflow-x:auto}
.zoom{display:block}
.hint{color:var(--mute)}
@media(max-width:480px){.mathd .katex{font-size:1em}}

.res{display:grid;grid-template-columns:1fr;gap:12px;margin:0 0 18px}
@media(min-width:640px){.res{grid-template-columns:1fr 1fr}}
.restile{display:flex;align-items:center;gap:12px;background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:12px 14px;text-decoration:none;color:var(--ink);box-shadow:var(--sh)}
.restile:hover{border-color:var(--acc)}
.restile .ic{background:var(--acc2);color:var(--acc)}
.restile:nth-child(2) .ic{background:#fff0d6;color:#b45309}
.rt{display:block;font-weight:700;font-size:18px;color:var(--ink)}
.rs{display:block;font-size:14px;color:var(--mute);line-height:1.45}
.fcgrid{list-style:none;padding:0;margin:0;display:grid;grid-template-columns:1fr;gap:12px}
@media(min-width:640px){.fcgrid{grid-template-columns:1fr 1fr}}
.fc{display:flex;gap:12px;background:var(--card);border:1px solid var(--line);border-inline-start:6px solid var(--tc,var(--acc));border-radius:var(--r);padding:10px;box-shadow:var(--sh)}
.fc img{width:110px;height:auto;border:1px solid var(--line);border-radius:8px;display:block}
.fcb h2{margin:0 0 4px;font-size:18px;color:var(--tc,var(--ink))}
.fcb p{margin:2px 0;font-size:15px}
.fclink{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:8px 12px;font-size:15px}
.myprog{background:var(--okl);border:1px solid #b7e2c4;border-radius:14px;padding:10px 14px;margin:0 0 16px;font-size:15px}
.myprog[hidden]{display:none}
.myprog button{font:inherit;font-size:13px;background:none;border:0;color:var(--mute);text-decoration:underline;cursor:pointer;padding:0 4px}

.pt{border:1px solid var(--line);border-radius:12px;margin:10px 0;padding:10px 10px;background:#fffdf9;position:relative}
.ptlbl{font-weight:700;margin:0 0 6px;font-size:16px;color:var(--tc,var(--ink))}
.tg{position:absolute;opacity:0;width:1px;height:1px;pointer-events:none}
.btns{display:flex;gap:8px}
.btn{flex:1 1 0;display:flex;align-items:center;justify-content:center;min-height:44px;padding:8px 6px;border:2px solid;border-radius:12px;background:#fff;font-weight:700;font-size:16px;cursor:pointer;user-select:none;text-align:center}
.btn.ba{border-color:#f0c35a;color:#8a5a00}
.btn.bb{border-color:#a5a0f0;color:var(--acc)}
.tga:checked~.btns .ba{background:#f5b301;border-color:#f5b301;color:#2b1d00}
.tgb:checked~.btns .bb{background:var(--acc);border-color:var(--acc);color:#fff}
.tga:focus-visible~.btns .ba,.tgb:focus-visible~.btns .bb{outline:3px solid var(--warm);outline-offset:2px}
.ansbox,.pt>.solbody{display:none}
.ansbox[hidden],.pt>.solbody[hidden]{display:none}
.tga:checked~.ansbox{display:block;background:var(--fin);border-inline-start:4px solid var(--finl);padding:8px 12px;border-radius:8px;margin-top:8px;font-weight:600}
.tgb:checked~.solbody{display:block;margin-top:8px}
.disc{background:#fff6e0;border:1px solid #f3d58a;border-radius:14px;padding:10px 14px;font-size:14px;color:#5b4a1a;margin:0 0 16px}
@media print{.pt>.solbody,.ansbox{display:block}.btns{display:none}}

/* calculator */
body.has-calc main{padding-bottom:84px}
.calc-fab{position:fixed;left:14px;bottom:14px;z-index:30;display:flex;align-items:center;gap:6px;min-height:48px;padding:8px 16px;border:0;border-radius:999px;background:linear-gradient(135deg,#4338ca,#6d28d9);color:#fff;font:inherit;font-size:16px;font-weight:700;box-shadow:0 6px 18px rgba(67,56,202,.35);cursor:pointer}
.calc-fab[hidden]{display:none}
.calc-fab:focus-visible,.calc button:focus-visible,.calc input:focus-visible{outline:3px solid var(--warm);outline-offset:2px}
.calc{position:fixed;left:0;right:0;bottom:0;z-index:40;background:#fff;border-radius:20px 20px 0 0;box-shadow:0 -8px 30px rgba(30,20,60,.25);padding:10px 12px 14px;max-height:92vh;overflow-y:auto}
.calc[hidden]{display:none}
@media(min-width:640px){.calc{left:16px;right:auto;bottom:16px;width:380px;border-radius:20px}}
.calc-head{display:flex;align-items:center;gap:8px;margin-bottom:8px}
.calc-tabs{flex:1;display:flex;gap:4px;background:#f3eee6;border-radius:999px;padding:3px}
.calc-tab{flex:1;border:0;background:none;font:inherit;font-size:15px;font-weight:700;color:var(--mute);border-radius:999px;padding:7px 6px;cursor:pointer;min-height:40px}
.calc-tab[aria-selected="true"]{background:#fff;color:var(--acc);box-shadow:0 1px 4px rgba(0,0,0,.12)}
.calc-x{flex:none;width:42px;height:42px;border:0;border-radius:50%;background:#f3eee6;font-size:18px;cursor:pointer;color:var(--ink)}
.calc-disp{background:#1e1b4b;color:#fff;border-radius:14px;padding:8px 14px;margin-bottom:8px;text-align:right;font-family:"Rubik",system-ui,sans-serif}
.calc-expr{min-height:24px;font-size:17px;opacity:.8;word-break:break-all}
.calc-res{font-size:28px;font-weight:700;min-height:40px;word-break:break-all}
.calc-res.err{color:#fca5a5;font-size:19px;line-height:1.35;padding-top:6px}
.calc-keys{display:grid;gap:6px;margin-bottom:6px;direction:ltr}
.k5{grid-template-columns:repeat(5,1fr)}
.k4{grid-template-columns:repeat(4,1fr)}
.k5.kc4{grid-template-columns:repeat(4,1fr)}
.ck.nrt{font-size:17px;letter-spacing:.5px}
.ck{min-height:46px;border:0;border-radius:12px;font:inherit;font-size:18px;font-weight:600;cursor:pointer;background:#f6f1ea;color:var(--ink)}
.k5 .ck{font-size:16px;min-height:42px;background:#eef0ff;color:var(--acc-d)}
.ck.num{background:#fff;border:1px solid var(--line);font-size:21px}
.ck.op{background:#ffe9c7;color:#8a4b00;font-size:22px}
.ck.eq{background:var(--acc);color:#fff;font-size:22px}
.k5 .ck.del{background:#fde2e2;color:#9b1c1c}
.ck:active{transform:scale(.96)}
.calc-note{margin:4px 0 0;font-size:12px;color:var(--mute);text-align:center}
.calc-eq{text-align:center;font-size:22px;font-weight:700;margin:4px 0 10px;color:var(--acc-d)}
.qf{display:flex;align-items:center;gap:8px;margin:0 0 8px}
.qf span{flex:none;width:44px;font-size:20px;font-weight:700;text-align:left}
.qf input{flex:1;min-width:0;min-height:46px;font:inherit;font-size:20px;border:2px solid var(--line);border-radius:12px;padding:4px 12px;text-align:left}
.qf input:focus{border-color:var(--acc)}
.qneg{flex:none;width:46px;height:46px;border:0;border-radius:12px;background:#eef0ff;color:var(--acc-d);font-size:20px;font-weight:700;cursor:pointer}
.qsolve{display:block;width:100%;min-height:48px;border:0;border-radius:12px;background:var(--acc);color:#fff;font:inherit;font-size:18px;font-weight:700;cursor:pointer;margin-top:4px}
.qout{margin-top:8px}
.qout p{margin:4px 0}
.qout .qd{text-align:center;font-size:18px}
.qout .qa{text-align:center;font-size:20px}
.qout .err{color:#b91c1c;text-align:center}
/* function mode (f(x) + CALC) */
.calc-tab{font-size:13px;padding:5px 4px;line-height:1.15}
.fxf{display:flex;align-items:center;gap:8px;margin:0 0 6px;border-radius:12px}
.fxf span{flex:none;width:58px;font-size:18px;font-weight:700;text-align:left;color:var(--mute)}
.fxf input{flex:1;min-width:0;min-height:44px;font:inherit;font-size:19px;border:2px solid var(--line);border-radius:12px;padding:4px 10px;text-align:left;background:#fff}
.fxf.on span{color:var(--acc-d)}
.fxf.on input{border-color:var(--acc);box-shadow:0 0 0 3px rgba(67,56,202,.12)}
.fx-res{min-height:40px;background:#1e1b4b;color:#fff;border-radius:12px;padding:6px 12px;margin:0 0 8px;font-size:20px;text-align:left;word-break:break-all;font-family:"Rubik",system-ui,sans-serif}
.fx-res b{font-size:24px}
.fx-res.err{color:#fca5a5;font-size:17px;text-align:right}
.fx-res.ask{color:#fde68a}
.ck.xk{background:#e0e7ff;color:#3730a3;font-weight:800;font-size:19px}
.k5 .ck.tgt{background:#fff;border:2px dashed var(--acc);font-size:15px}
.ck.calck{font-size:17px;font-weight:800;letter-spacing:.5px}
.fx-hist{margin:4px 0 0}
.fx-hh{display:flex;justify-content:space-between;align-items:center;font-size:13px;font-weight:700;color:var(--mute);margin:0 2px 4px}
.fx-clr{border:0;background:none;color:var(--acc);font:inherit;font-size:13px;cursor:pointer;padding:4px 6px}
.fx-hist table{width:100%;border-collapse:collapse;font-size:16px;background:#faf7f2;border-radius:10px;overflow:hidden}
.fx-hist th,.fx-hist td{padding:4px 10px;border-bottom:1px solid var(--line);text-align:left}
.fx-hist th{font-size:13px;color:var(--mute);font-weight:700;word-break:break-all}
.fx-hist td:first-child,.fx-hist th:first-child{width:38%;border-right:1px solid var(--line)}
.fx-hist td.err{color:#b91c1c}
/* per-question print */
.prt{display:flex;flex-wrap:wrap;gap:8px;margin:10px 0 0}
.prt[hidden]{display:none}
.prb{border:1.5px solid var(--line);background:#fff;color:var(--ink);font:inherit;font-size:14px;font-weight:600;border-radius:999px;padding:7px 14px;min-height:40px;cursor:pointer}
.prb:hover{border-color:var(--acc);color:var(--acc-d)}
#printroot{display:none}
@media screen{body.printing-q #printroot{display:block;position:absolute;left:-10000px;top:0;width:720px;pointer-events:none}}
@media print{
  @page{size:A4;margin:12mm}
  body.printing-q{background:#fff!important;color:#000!important}
  body.printing-q>*:not(#printroot){display:none!important}
  body.printing-q #printroot{display:block!important;color:#000;font-size:12pt}
  #printroot *{color:#000!important;background:transparent!important;box-shadow:none!important;border-color:#888!important}
  #printroot .prhead{position:relative;text-align:center;border-bottom:1.5pt solid #000;padding:0 0 6pt;margin:0 0 10pt}
  #printroot .prbsd{position:absolute;top:0;right:0;font-size:10pt}
  #printroot .prsub{margin:0;font-size:10pt}
  #printroot h1{margin:4pt 0 2pt;font-size:17pt}
  #printroot .prtopic{margin:0;font-size:11pt}
  #printroot .qimg{margin:0;break-inside:avoid;page-break-inside:avoid}
  #printroot .qimg img{display:block;width:100%;height:auto;max-width:none;border:0;break-inside:avoid;page-break-inside:avoid}
  #printroot .prsolh{font-size:14pt;margin:12pt 0 6pt;border-bottom:1pt solid #000;padding-bottom:3pt;break-after:avoid}
  #printroot .pt{border:0;padding:0;margin:0 0 10pt}
  #printroot .ptlbl{font-weight:700;font-size:12pt;margin:6pt 0 3pt;break-after:avoid}
  #printroot .solbody{display:block!important}
  #printroot .solbody img,#printroot svg,#printroot .katex-display{break-inside:avoid;page-break-inside:avoid}
  #printroot .prfoot{margin-top:14pt;border-top:1pt solid #999;padding-top:4pt;font-size:8.5pt;text-align:center}
  .prt{display:none!important}
}
/* standalone calculator page */
@media(max-width:560px){.topnav .navcalc{display:none}}
.calc.calc-inline{position:static;max-height:none;overflow:visible;border-radius:20px;box-shadow:0 6px 24px rgba(30,20,60,.12);margin:0 auto 18px;max-width:440px;padding:12px}
.calcpage h1{font-size:24px;margin:6px 0 4px;text-align:center}
.calcpage .lead{text-align:center;margin:0 0 12px}
.calcpage .back{text-align:center;margin:8px 0 0}
@media print{.calc,.calc-fab{display:none}}
.nw{white-space:nowrap}