:root{
  --page:#e8edf2;--paper:#fff;--panel:#f5f7fa;--panel2:#edf1f5;--ink:#162033;--muted:#687386;
  --line:#ccd4de;--line-dark:#aab5c2;--nav:#182238;--nav2:#26334d;--blue:#2463eb;--blue-dark:#1749ba;
  --orange:#f05a28;--green:#187759;--green-bg:#eaf7f1;--red:#ae3434;--red-bg:#fff0f0;--yellow:#fff5c9;
  --shadow:0 1px 2px rgba(20,35,55,.06)
}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--page);color:var(--ink);font:15px/1.5 Arial,Helvetica,sans-serif}
a{color:#1654b8;text-decoration:none}a:hover{text-decoration:underline}button,input,select,textarea{font:inherit}button{cursor:pointer}
.site{max-width:1260px;margin:10px auto 24px;background:var(--paper);border:1px solid #aab4c0;box-shadow:0 3px 17px rgba(23,36,58,.06)}
.utility{height:29px;padding:0 10px;display:flex;align-items:center;justify-content:space-between;background:#f1f4f7;border-bottom:1px solid var(--line);font-size:11px;color:var(--muted)}
.header{display:grid;grid-template-columns:1fr 310px;min-height:84px;border-bottom:1px solid var(--line);background:#fff}.brand{display:flex;align-items:center;gap:12px;padding:14px 16px;color:var(--ink);text-decoration:none;border-right:1px solid var(--line)}.brand:hover{text-decoration:none}.brand-mark{width:46px;height:46px;background:var(--orange);color:#fff;display:grid;place-items:center;font:800 22px/1 Georgia,serif;transform:rotate(-2deg)}.brand-copy strong{display:block;font-size:27px;line-height:1;letter-spacing:-.7px}.brand-copy strong span{color:var(--blue)}.brand-copy small{display:block;margin-top:7px;color:#667085;font-size:12px}.head-tool{padding:12px 14px;background:#f7f9fb}.head-tool b{display:block;font-size:12px;margin-bottom:7px}.mini-search{display:grid;grid-template-columns:1fr auto;gap:5px}.mini-search input{height:35px;border:1px solid var(--line-dark);padding:6px 8px;background:#fff}.mini-search button{border:0;background:var(--blue);color:#fff;font-weight:700;padding:0 13px}
.main-nav{display:flex;overflow:auto;background:var(--nav);border-bottom:3px solid var(--orange);white-space:nowrap}.main-nav a{color:#fff;padding:9px 13px;font-size:13px;font-weight:700;border-right:1px solid #35415a}.main-nav a:hover{background:var(--nav2);text-decoration:none}
.layout{display:grid;grid-template-columns:185px minmax(0,1fr) 250px;grid-template-areas:"left main right";min-height:700px}.left{grid-area:left;background:#f2f5f8;border-right:1px solid var(--line);padding:7px}.main{grid-area:main;padding:8px;min-width:0}.right{grid-area:right;background:#f2f5f8;border-left:1px solid var(--line);padding:7px}
.side-box,.box{border:1px solid var(--line-dark);background:#fff;margin-bottom:8px;box-shadow:var(--shadow)}.side-head,.box-head{min-height:31px;padding:7px 9px;background:var(--nav2);color:#fff;font-size:11px;font-weight:800;letter-spacing:.045em;text-transform:uppercase;border-bottom:1px solid #111b2e}.box-head.blue{background:#2459b9}.box-head.orange{background:#dc4d20}.box-head.green{background:#187452}.side-list a{display:block;padding:7px 8px;border-bottom:1px solid #dbe1e7;color:#25324a;font-size:12px}.side-list a:last-child{border-bottom:0}.side-list a:hover{background:#eef4fb;text-decoration:none}.side-note{padding:9px;background:var(--yellow);font-size:11px;color:#584d22}.side-note strong{display:block;color:#362e12;margin-bottom:3px}
.breadcrumbs{min-height:31px;display:flex;align-items:center;gap:6px;padding:5px 8px;background:#f3f5f7;border:1px solid var(--line);font-size:11px;color:#778195;overflow:auto;white-space:nowrap}.breadcrumbs a{color:#546276}h1{font-size:30px;line-height:1.14;letter-spacing:-.65px;margin:11px 2px 7px;color:#14203a}h2{font-size:20px;line-height:1.25;margin:0 0 8px}h3{font-size:15px;margin:0 0 6px}p{margin:7px 0}.lead{font-size:15px;color:#475467;margin:0 2px 10px;max-width:850px}
.quick-strip{display:grid;grid-template-columns:1.25fr 1fr 1fr;border:1px solid var(--line-dark);margin-bottom:8px;background:#fff}.quick-strip>div{padding:7px 9px;border-right:1px solid var(--line)}.quick-strip>div:last-child{border-right:0}.quick-strip b{display:block;font-size:10px;color:#667085;text-transform:uppercase;margin-bottom:2px}.quick-strip span{font-weight:700;font-size:13px}
.hero-grid{display:grid;grid-template-columns:minmax(0,.95fr) minmax(320px,1.05fr)}.rule{padding:12px 13px;background:#fbfcfd;border-right:1px solid var(--line)}.rule ol{margin:8px 0 10px;padding-left:20px}.rule li{margin:5px 0}.home-links{display:flex;gap:14px;margin-top:10px;font-size:12px}
.formula-line{min-height:70px;display:flex;align-items:center;justify-content:center;gap:10px;padding:8px;margin-top:11px;background:#fff;border:1px solid var(--line);font:700 25px/1 Georgia,"Times New Roman",serif;white-space:nowrap;overflow:auto}.frac{display:inline-grid;grid-template-rows:auto auto;vertical-align:middle;min-width:24px;text-align:center;line-height:1.04;font-family:Georgia,"Times New Roman",serif}.frac .top{border-bottom:1.6px solid currentColor;padding:0 4px 3px}.frac .bottom{padding:3px 4px 0}.formula-line .eq,.formula-line .op{font-family:Arial,sans-serif;font-weight:500;font-size:22px}
.calc{padding:12px 13px;background:#f1f5fa}.calc-large{padding:18px}.calc-widget{text-align:center}.calc-expression{display:grid;grid-template-columns:1fr 38px 1fr;gap:8px;align-items:center;max-width:410px;margin:10px auto 12px}.frac-input{display:grid;gap:4px}.frac-input input{height:40px;text-align:center;border:1px solid #8f9bad;background:#fff;font-size:18px;font-weight:700;min-width:0}.frac-input i,.converter-input i{display:block;height:2px;background:#172033;margin:0 7px}.calc-op{text-align:center;font-size:26px;font-weight:700}.primary{border:1px solid #1746ab;background:var(--blue);color:#fff;font-weight:800;padding:9px 14px}.primary:hover{background:var(--blue-dark)}.secondary{border:1px solid #9ca8b7;background:#fff;color:#344054;font-weight:700;padding:8px 12px}.calc-result{display:none;margin:10px auto 0;padding:10px;border:1px solid #9ab5de;background:#fff;text-align:left;max-width:520px}.calc-result.show{display:block}.calc-answer{display:flex;align-items:center;gap:8px;font-size:18px;font-weight:800;color:#123f92;margin-bottom:7px}.calc-result ol{margin:5px 0;padding-left:20px;font-size:12px}.calc-result li{margin:4px 0}.op-tabs{display:flex;justify-content:center;gap:4px;margin-bottom:8px}.op-tabs button{width:42px;height:32px;border:1px solid #aeb8c5;background:#fff;font-weight:800}.op-tabs button.active{background:var(--nav2);color:#fff;border-color:var(--nav2)}
.ad-slot{display:block;overflow:hidden;text-align:center;background:#fff}.ad-top,.ad-incontent{margin:8px 0}.ad-sidebar{margin-bottom:8px}.ad-slot img{max-width:100%;height:auto}.ad-slot iframe{max-width:100%}
.steps{display:grid;grid-template-columns:repeat(3,1fr)}.step{padding:10px;border-right:1px solid var(--line);min-width:0}.step:last-child{border-right:0}.step-no{font-size:10px;font-weight:800;color:#fff;background:var(--blue);display:inline-block;padding:2px 5px;margin-bottom:5px}.step p{font-size:12px;color:#475467;margin:4px 0}.text-pad{padding:11px 12px}.text-pad.legal{font-size:13px;color:#475467}.text-pad p:first-child{margin-top:0}.text-pad p:last-child{margin-bottom:0}
.trainer-box{overflow:hidden}.trainer-toolbar{display:grid;grid-template-columns:1fr auto;align-items:center;padding:8px 10px;background:#f3f6f9;border-bottom:1px solid var(--line)}.trainer-toolbar strong{text-transform:capitalize;font-size:13px}.trainer-toolbar>[data-progress]{font-size:11px;color:#667085}.progress{grid-column:1/-1;height:4px;background:#d9e0e8;margin-top:7px}.progress i{display:block;width:0;height:100%;background:var(--orange);transition:.2s}.task-zone{padding:12px}.task-meta{font-size:11px;color:#667085}.task-math{display:flex;align-items:center;justify-content:center;gap:11px;min-height:88px;font:700 28px Georgia,serif}.task-math .op{font-family:Arial,sans-serif;font-weight:600}.answer-row{display:grid;grid-template-columns:140px 140px auto;gap:6px;justify-content:center;align-items:center}.answer-row input{height:39px;border:1px solid #8f9bad;text-align:center;font-weight:700;min-width:0}.compare-answer{display:flex;gap:7px;justify-content:center}.compare-answer button{width:58px;height:43px;border:1px solid #9ba7b7;background:#fff;font-size:22px;font-weight:800}.compare-answer button:hover{border-color:var(--blue);background:#edf4ff}.task-links{display:flex;justify-content:center;gap:16px;margin-top:9px}.linkbtn{border:0;padding:0;background:none;color:#1955b6;text-decoration:underline;font-size:12px}.feedback{display:none;margin:9px auto 0;padding:8px 9px;font-size:12px;border:1px solid;max-width:620px}.feedback.good{display:block;border-color:#8dc2aa;background:var(--green-bg);color:#146241}.feedback.bad{display:block;border-color:#d8a0a0;background:var(--red-bg);color:#8f2d2d}.feedback.info{display:block;border-color:#aab9cf;background:#f4f7fb;color:#394966}.feedback ol{margin:6px 0 0;padding-left:20px}.session-stats{padding:8px}.session-stats span{display:flex;justify-content:space-between;padding:5px 2px;border-bottom:1px solid #e1e6ec;font-size:12px}.session-stats span:last-child{border:0}
.topic-grid,.link-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px;margin-bottom:8px}.topic-card,.link-grid>a{border:1px solid var(--line-dark);background:#fff;padding:11px 12px;color:var(--ink);text-decoration:none}.topic-card:hover,.link-grid>a:hover{border-color:#7f94af;background:#fafcff;text-decoration:none}.topic-card strong,.link-grid strong{display:block;color:#17499e;font-size:15px;margin-bottom:3px}.topic-card span,.link-grid span{display:block;color:#687386;font-size:12px}.related-list{display:grid;grid-template-columns:repeat(2,minmax(0,1fr))}.related-list a{display:flex;justify-content:space-between;gap:10px;padding:8px 10px;border-right:1px solid var(--line);border-bottom:1px solid var(--line);font-size:13px}.related-list a:nth-child(2n){border-right:0}.related-list a:nth-last-child(-n+2){border-bottom:0}.related-list span{color:#8993a1}.definition-grid{display:grid;grid-template-columns:1fr 1fr}.definition-grid>div{padding:12px;border-right:1px solid var(--line)}.definition-grid>div:last-child{border:0}.definition-grid h2{font-size:16px}.definition-grid p{font-size:13px;color:#566174}
.curriculum{padding:4px 10px}.curriculum>div{display:grid;grid-template-columns:28px 1fr;gap:9px;padding:9px 0;border-bottom:1px solid #e1e6ec}.curriculum>div:last-child{border:0}.curriculum>div>b{width:24px;height:24px;display:grid;place-items:center;background:#edf3fb;color:#1d55a4;font-size:11px}.curriculum strong{display:block;font-size:13px}.curriculum small{display:block;color:#687386;margin-top:2px}.visual-task{display:grid;grid-template-columns:220px 1fr;gap:20px;align-items:center;padding:18px}.pie-row{display:grid;grid-template-columns:repeat(4,1fr);height:58px;border:2px solid #26334d}.pie-row>*{border-right:1px solid #26334d;background:#f9a483}.pie-row>*:last-child{border:0;background:#fff}.visual-task .frac{font-size:18px;margin:0 5px}.skill-switch{display:flex;overflow:auto;gap:5px;margin:0 0 8px}.skill-switch button{border:1px solid #9faab8;background:#fff;padding:7px 10px;font-size:12px;font-weight:700;white-space:nowrap}.skill-switch button.active{background:var(--nav2);color:#fff}
.converter{display:grid;grid-template-columns:180px auto 1fr;gap:12px;align-items:center;padding:18px;background:#f2f6fb}.converter-input{display:grid;gap:4px}.converter-input input{height:40px;text-align:center;border:1px solid #8f9bad;font-size:18px;font-weight:700}.converter-result{font-size:21px;font-weight:800;color:#153d82}.fraction-hero{display:grid;grid-template-columns:210px 1fr;border:1px solid var(--line-dark);background:#fff;margin-bottom:8px}.fraction-big{display:flex;align-items:center;justify-content:center;background:#f0f4f9;border-right:1px solid var(--line);font-size:48px;padding:24px}.fraction-facts{display:grid;grid-template-columns:repeat(2,1fr)}.fraction-facts>div{padding:13px;border-right:1px solid var(--line);border-bottom:1px solid var(--line)}.fraction-facts>div:nth-child(2n){border-right:0}.fraction-facts>div:nth-last-child(-n+2){border-bottom:0}.fraction-facts b{display:block;text-transform:uppercase;color:#7a8493;font-size:10px;margin-bottom:4px}.fraction-facts strong{font-size:18px}.equiv{display:flex;gap:18px;align-items:center;justify-content:center;padding:20px;font-size:24px;overflow:auto}.equiv>span{display:inline-flex;align-items:center}.search-results{display:grid;border:1px solid var(--line-dark);margin-bottom:8px}.search-results a{padding:10px 12px;border-bottom:1px solid var(--line);text-decoration:none}.search-results a:last-child{border:0}.search-results a:hover{background:#f6f9fc}.search-results strong{display:block}.search-results span{display:block;margin-top:3px;font-size:12px;color:#687386}.empty{padding:18px;border:1px solid var(--line-dark);background:#fff;margin-bottom:8px}.footer{display:flex;justify-content:space-between;gap:16px;padding:13px 10px;background:#eef2f6;border-top:1px solid var(--line);font-size:11px;color:#697586}
@media(max-width:1020px){.layout{grid-template-columns:160px minmax(0,1fr);grid-template-areas:"left main"}.right{display:none}.site{margin:0;border-left:0;border-right:0}.steps{grid-template-columns:1fr}.step{border-right:0;border-bottom:1px solid var(--line)}.step:last-child{border-bottom:0}}
@media(max-width:760px){body{background:#fff}.site{border:0;box-shadow:none}.utility{display:none}.header{grid-template-columns:1fr;min-height:0}.brand{border-right:0;padding:11px 12px}.brand-mark{width:40px;height:40px}.brand-copy strong{font-size:24px}.head-tool{border-top:1px solid var(--line)}.layout{display:block}.left{display:none}.main{padding:7px}.main-nav a{padding:9px 11px}.breadcrumbs{margin-bottom:4px}h1{font-size:26px;margin-top:9px}.hero-grid{grid-template-columns:1fr}.rule{border-right:0;border-bottom:1px solid var(--line)}.quick-strip{grid-template-columns:1fr}.quick-strip>div{border-right:0;border-bottom:1px solid var(--line)}.quick-strip>div:last-child{border-bottom:0}.topic-grid,.link-grid,.related-list,.definition-grid{grid-template-columns:1fr}.related-list a,.definition-grid>div{border-right:0}.related-list a:nth-last-child(2){border-bottom:1px solid var(--line)}.answer-row{grid-template-columns:1fr 1fr}.answer-row .primary{grid-column:1/-1}.converter{grid-template-columns:1fr}.fraction-hero{grid-template-columns:1fr}.fraction-big{border-right:0;border-bottom:1px solid var(--line)}.visual-task{grid-template-columns:1fr}.pie-row{max-width:260px}.footer{display:block}.footer>div+div{margin-top:5px}}
@media(max-width:420px){.brand-copy small{font-size:11px}.calc-expression{grid-template-columns:1fr 30px 1fr}.frac-input input{height:38px}.formula-line{font-size:22px}.task-math{font-size:25px}.fraction-facts{grid-template-columns:1fr}.fraction-facts>div{border-right:0}.fraction-facts>div:nth-last-child(2){border-bottom:1px solid var(--line)}}

/* v1.1 content and math tools */
.content-block .text-pad{font-size:14px;line-height:1.62}.content-block .text-pad p{max-width:850px}.plain-list{margin:7px 0 2px;padding-left:21px}.plain-list li{margin:5px 0}.faq-list details{border-bottom:1px solid var(--line)}.faq-list details:last-child{border-bottom:0}.faq-list summary{padding:10px 12px;font-weight:700;cursor:pointer}.faq-list p{padding:0 12px 11px;margin:0;color:#536174;font-size:13px}.text-link{font-weight:700}.calc-extra{font-size:12px;color:#556174;margin-top:7px}.error{color:#9a2e2e}.home-links{flex-wrap:wrap}
.converter-advanced{display:flex;flex-wrap:wrap;justify-content:center;gap:10px 12px}.converter-advanced .converter-input{width:150px}.converter-advanced .primary{min-height:40px}.converter-advanced .converter-result{flex:1 1 240px;min-width:220px}.single-value{width:180px;height:42px;border:1px solid #8f9bad;background:#fff;padding:8px 10px;font-size:18px;font-weight:700;text-align:center}.mixed-input{display:flex;align-items:center;gap:9px}.mixed-input>input{width:120px;height:42px;border:1px solid #8f9bad;text-align:center;font-weight:700}.percent-input{display:flex;align-items:center;gap:6px}.percent-input span,.of-label{font-weight:800;color:#4f5b6d}.converter-result ol{font-size:12px;font-weight:400;color:#4e5c70;margin:8px 0 0;padding-left:20px}.conv-note{font-size:13px;font-weight:500;color:#697586}
.decimal-calc{padding:16px;background:#f2f6fb}.decimal-op-tabs{display:flex;gap:4px;justify-content:center;margin-bottom:11px}.decimal-op-tabs button{width:42px;height:32px;border:1px solid #aab5c2;background:#fff;font-weight:800}.decimal-op-tabs button.active{background:var(--nav2);border-color:var(--nav2);color:#fff}.decimal-row{display:grid;grid-template-columns:minmax(120px,1fr) 30px minmax(120px,1fr) auto;gap:7px;align-items:center;max-width:650px;margin:0 auto}.decimal-row input{height:42px;border:1px solid #8f9bad;padding:8px 10px;text-align:center;font-size:17px;font-weight:700;min-width:0}.decimal-row>b{text-align:center;font-size:21px}.decimal-calc .calc-result{max-width:650px}
.box>.link-grid{margin:0;border:0}.box>.link-grid>a{border-top:0}.box>.link-grid>a:nth-child(odd){border-left:0}.box>.link-grid>a:nth-child(even){border-right:0}.box>.link-grid>a:nth-last-child(-n+2){border-bottom:0}
@media(max-width:760px){.converter-advanced{display:grid;grid-template-columns:1fr}.converter-advanced .converter-input,.single-value,.mixed-input>input{width:100%}.mixed-input{display:grid;grid-template-columns:1fr 1fr}.converter-advanced .converter-result{min-width:0}.decimal-row{grid-template-columns:1fr 28px 1fr}.decimal-row .primary{grid-column:1/-1}.box>.link-grid>a{border-left:0!important;border-right:0!important}.box>.link-grid>a:nth-last-child(2){border-bottom:1px solid var(--line)}}

/* v2.0 full SEO/content layer */
.seo-text-box .text-pad{font-size:14px;line-height:1.65;background:#fbfcfe}.seo-text-box p{max-width:900px}
.fraction-links{padding:12px;margin-top:0}.fraction-links a{display:inline-flex;align-items:center;justify-content:center;min-width:58px;padding:7px 9px;border:1px solid var(--line);background:#f7f9fc;font-weight:700}.fraction-links a:hover{background:#eef4fb;text-decoration:none}
.fraction-catalog-group{margin-bottom:8px}.fraction-catalog-grid{display:grid;grid-template-columns:repeat(8,minmax(0,1fr));gap:0}.fraction-catalog-grid a{display:block;padding:9px 8px;text-align:center;border-right:1px solid var(--line);border-bottom:1px solid var(--line);font-weight:700;background:#fff}.fraction-catalog-grid a:nth-child(8n){border-right:0}.fraction-catalog-grid a:hover{background:#eef4fb;text-decoration:none}
.content-block .plain-list{columns:1}.content-block .plain-list li::marker{color:#2459b9}
@media(max-width:1020px){.fraction-catalog-grid{grid-template-columns:repeat(6,minmax(0,1fr))}.fraction-catalog-grid a:nth-child(8n){border-right:1px solid var(--line)}.fraction-catalog-grid a:nth-child(6n){border-right:0}}
@media(max-width:760px){.fraction-catalog-grid{grid-template-columns:repeat(4,minmax(0,1fr))}.fraction-catalog-grid a:nth-child(6n){border-right:1px solid var(--line)}.fraction-catalog-grid a:nth-child(4n){border-right:0}.content-block .text-pad,.seo-text-box .text-pad{font-size:14px}}
@media(max-width:420px){.fraction-catalog-grid{grid-template-columns:repeat(3,minmax(0,1fr))}.fraction-catalog-grid a:nth-child(4n){border-right:1px solid var(--line)}.fraction-catalog-grid a:nth-child(3n){border-right:0}}

/* v2.2 final content */
.worked-example .worked-steps{margin:0;padding-left:1.35rem;display:grid;gap:.55rem}
.worked-example .worked-steps li{padding-left:.2rem;line-height:1.55}
.worked-example .worked-answer{margin:1rem 0 0;padding-top:.8rem;border-top:1px solid var(--line,#d9d9d9)}