@import url('/assets/fonts/fonts.css');
*{box-sizing:border-box}body{margin:0;background:#f5f7f8;color:#183e50;font-family:'DM Sans',sans-serif}header{display:flex;justify-content:space-between;padding:18px 4%;border-bottom:1px solid #ccd6da}a{color:inherit}main{max-width:1180px;padding:24px;margin:auto}.eyebrow{font-size:12px;letter-spacing:3px}h1{font:700 38px Literata,serif;margin:8px 0 22px}button{font:inherit;color:inherit;background:white;border:1px solid #8197a2;border-radius:10px;padding:12px;min-height:46px;cursor:pointer}button:disabled{cursor:default;opacity:.55}button:focus-visible,a:focus-visible{outline:3px solid #dca51e;outline-offset:3px}.skip{position:absolute;top:-100px}.skip:focus{top:0}#levels{display:grid;grid-template-columns:repeat(3,1fr);gap:14px;margin:28px 0}.level{text-align:left;padding:22px;min-height:145px}.level strong{font-size:22px;display:block}.level small{display:block;margin:12px 0 0;line-height:1.5}.level.available{border:2px solid #47735a;background:#f4faf5}.toolbar{display:flex;align-items:center;gap:20px;flex-wrap:wrap;margin-bottom:18px}.mat{border:4px solid #111;background:white;padding:26px}.mat h2{text-align:center;font:600 30px Literata,serif;margin:0}.directions{text-align:center;margin-bottom:30px}.work-layout{display:grid;grid-template-columns:240px minmax(0,1fr);gap:32px}aside h3{font-size:15px;margin-top:0}#tiles{display:grid;grid-template-columns:1fr 1fr;gap:12px}.tile{border:3px solid;border-radius:5px;font-size:22px;font-weight:600;touch-action:none;user-select:none}.add{border-color:#328141;color:#246a30;background:#f1f9f1}.sub{border-color:#df3636;color:#ae2525;background:#fff4f3}.mul{border-color:#3269bd;color:#255499;background:#f1f5ff}.div{border-color:#ce39b4;color:#a4218e;background:#fff2fc}.tile.selected{outline:3px solid #dca51e;outline-offset:3px}.equation,.slots,.applied{display:grid;grid-template-columns:minmax(0,1fr) 30px minmax(0,1fr);align-items:center;text-align:center;gap:6px}.equation{font-size:clamp(22px,3vw,36px);font-weight:600;margin:16px 0;overflow-wrap:anywhere}.slots{margin:14px 0 22px}.slot{background:#dedede;border:2px dashed #949494;border-radius:3px;min-height:72px;min-width:72px;width:fit-content;justify-self:center;font-size:22px}.slot.filled{border-style:solid}.applied{font-size:20px;color:#286c42;margin:10px 0 24px;border-bottom:1px solid #dce4df;padding-bottom:15px}.applied span:not(:nth-child(2)){background:#eef8ef;border:2px solid #4d9d61;border-radius:6px;padding:8px;justify-self:center}.solution{color:#267c42;border:2px solid #53a565;padding:12px;border-radius:8px}.wrong .slot{border:3px solid #dc3838;background:#fff0f0}#feedback{min-height:25px}#next{background:#2c654b;color:white}dialog{border:2px solid #486777;border-radius:14px;max-width:440px;padding:25px}dialog::backdrop{background:#102a3c99}dialog button{margin:5px}.ghost{position:fixed;pointer-events:none;z-index:10;opacity:.85}#results{background:white;border:2px solid #3b8157;border-radius:12px;padding:30px}#results button{margin:8px} [hidden]{display:none!important}@media(max-width:760px){#levels{grid-template-columns:1fr 1fr}.work-layout{grid-template-columns:1fr}.mat{padding:14px}#tiles{grid-template-columns:repeat(4,minmax(0,1fr));gap:8px}.tile{font-size:17px;padding:8px}.toolbar{gap:10px}main{padding:14px}}@media(max-width:420px){#levels{grid-template-columns:1fr}.equation{font-size:24px}#tiles{grid-template-columns:repeat(3,minmax(0,1fr))}}@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto}}
.equation-row{display:grid;grid-template-columns:minmax(0,1fr) 30px minmax(0,1fr);gap:12px;margin:16px 0 24px;padding-bottom:18px;border-bottom:1px solid #dce4df}.expression,.equals{font-size:clamp(22px,3vw,36px);font-weight:600;line-height:1.5;text-align:center}.expression{min-height:54px;display:flex;justify-content:center;align-items:center;white-space:nowrap}.spread-side .expression{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:4px}.inverse-position{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));margin-top:12px;justify-items:center}.inverse-position>*{grid-column:1/4}.spread-side .inverse-position>*{grid-column:2/4}.placed-inverse{display:inline-block;padding:12px;min-width:72px;text-align:center}.locked{box-shadow:0 0 5px #4d9d6144}.slot.filled.add{background:#f1f9f1;border-color:#328141;color:#246a30}.slot.filled.sub{background:#fff4f3;border-color:#df3636;color:#ae2525}.slot.filled.mul{background:#f1f5ff;border-color:#3269bd;color:#255499}.slot.filled.div{background:#fff2fc;border-color:#ce39b4;color:#a4218e}.wrong .slot.filled{border-color:#dc3838;background:#fff0f0}.equation-row.solution{border:2px solid #53a565;padding:12px}@media(max-width:500px){.equation-row{gap:6px;grid-template-columns:minmax(0,1fr) 22px minmax(0,1fr)}.expression,.equals{font-size:clamp(16px,5vw,24px)}.slot,.placed-inverse{min-width:54px;min-height:56px;font-size:18px;padding:8px}.expression{white-space:normal;overflow-wrap:anywhere}}
/* Keep each inverse directly beneath its compact equation side. */
.equation-row{max-width:420px;margin:12px auto 18px;grid-template-columns:minmax(0,1fr) 24px minmax(0,1fr);gap:8px;padding-bottom:12px}.expression{min-height:44px}.inverse-position{margin-top:6px}.work-layout{gap:24px}.working #feedback,.working #next{margin-left:0}
.fraction{display:inline-flex;flex-direction:column;align-items:stretch;text-align:center;vertical-align:middle;line-height:1.15;margin:0 5px}.numerator{border-bottom:2px solid currentColor;padding:0 7px 5px}.denominator{padding:5px 7px 0}.equation-row{align-items:center}.equation-side.beside{display:flex;align-items:center;justify-content:center;gap:10px}.beside.side-0 .inverse-position{order:-1}.beside .inverse-position{display:block;margin:0;flex-shrink:0}.beside .expression{min-width:0}.equation-row:has(.beside){max-width:560px;grid-template-columns:minmax(0,1fr) 24px minmax(0,1fr)}@media(max-width:500px){.equation-side.beside{gap:5px}.beside .slot,.beside .placed-inverse{min-width:44px;padding:5px;font-size:16px}.fraction{margin:0 2px}}
.choice-side{display:grid;grid-template-columns:72px minmax(0,1fr);grid-template-rows:auto auto;gap:10px;align-items:center}.choice-side .expression{grid-column:2;grid-row:1}.outside-choice{grid-column:1;grid-row:1;justify-self:center}.below-choice{grid-column:2;grid-row:2;justify-self:center}.choice-side.side-1{grid-template-columns:minmax(0,1fr) 72px}.choice-side.side-1 .expression{grid-column:1}.choice-side.side-1 .outside-choice{grid-column:2}.choice-side.side-1 .below-choice{grid-column:1}.equation-row:has(.choice-side){max-width:620px;align-items:start}.equation-row:has(.choice-side) .equals{padding-top:10px}.division-placement{position:relative}.division-placement:before{content:'';position:absolute;top:-7px;left:-8px;right:-8px;border-top:2px solid #183e50}.dividing-side .inverse-position{border-top:2px solid currentColor;padding-top:8px}@media(max-width:500px){.choice-side{grid-template-columns:44px minmax(0,1fr);gap:8px 4px}.choice-side.side-1{grid-template-columns:minmax(0,1fr) 44px}.choice-side .slot{min-width:44px;min-height:50px;padding:4px;font-size:16px}.choice-side .expression{font-size:18px}.equation-row:has(.choice-side){gap:4px;grid-template-columns:minmax(0,1fr) 18px minmax(0,1fr)}}
.term-layout .expression,.choice-side .expression:has(.term-first){display:grid;grid-template-columns:1fr 1fr;gap:8px}.term-first,.term-last{display:flex;align-items:center;justify-content:center;gap:6px}.term-layout .inverse-position{grid-template-columns:1fr 1fr}.anchor-first .inverse-position>*{grid-column:1}.anchor-last .inverse-position>*{grid-column:2}.choice-side.anchor-last .below-choice{justify-self:end}.choice-side.anchor-first .below-choice{justify-self:start}.equation-row:has(.term-layout){max-width:620px}.term-last{white-space:nowrap}