/* Mathwright site — colours match the games */
:root{
  --navy:#12263f; --navy-2:#1b3557;
  --teal:#125e78; --teal-d:#0d485c; --teal-l:#e2f0f5;
  --gold:#b57d18; --gold-2:#e8b04b; --gold-l:#fdf3dd;
  --bg:#f5f8fb; --bg-2:#eef2f7; --panel:#fff;
  --ink:#12263f; --ink-2:#3c4d63; --muted:#5d6e83;
  --line:#d3dce7; --line-2:#e6ecf3;
  --good:#1a7a43;
  --radius:14px;
  --shadow:0 1px 2px rgba(18,38,63,.06),0 4px 16px rgba(18,38,63,.07);
  --font:"Segoe UI",system-ui,-apple-system,Roboto,"Helvetica Neue",Arial,sans-serif;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;font-family:var(--font);color:var(--ink);background:var(--bg);line-height:1.6;font-size:17px}
img,svg{max-width:100%;display:block}
a{color:var(--teal)}
a:hover{color:var(--teal-d)}
h1,h2,h3{line-height:1.2;margin:0 0 .5em;letter-spacing:-.01em}
h1{font-size:clamp(2rem,4.4vw,3.1rem);font-weight:800}
h2{font-size:clamp(1.4rem,2.6vw,1.85rem);font-weight:750}
h3{font-size:1.15rem;font-weight:700}
p{margin:0 0 1em}
.wrap{max-width:1160px;margin:0 auto;padding:0 20px}
.narrow{max-width:760px}
.skip{position:absolute;left:-999px;top:8px;background:#fff;padding:8px 12px;z-index:10}
.skip:focus{left:8px}
:focus-visible{outline:3px solid var(--gold-2);outline-offset:2px;border-radius:4px}

/* header */
.site-head{background:var(--panel);border-bottom:1px solid var(--line-2);position:sticky;top:0;z-index:5}
.head-row{display:flex;align-items:center;justify-content:space-between;height:64px;gap:16px}
.brand{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--navy);font-weight:800;font-size:1.2rem;letter-spacing:-.01em}
.logo-mark{width:32px;height:32px}
.nav{display:flex;gap:4px}
.nav a{color:var(--ink-2);text-decoration:none;font-weight:600;padding:8px 12px;border-radius:8px;font-size:.98rem}
.nav a:hover{background:var(--bg-2);color:var(--navy)}
.nav a[aria-current="page"]{color:var(--teal);background:var(--teal-l)}

/* buttons */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;background:var(--teal);color:#fff;text-decoration:none;font-weight:700;padding:12px 22px;border-radius:10px;border:2px solid var(--teal);transition:background .15s,transform .15s;font-size:1rem}
.btn:hover{background:var(--teal-d);border-color:var(--teal-d);color:#fff}
.btn:active{transform:translateY(1px)}
.btn-ghost{background:transparent;color:var(--teal)}
.btn-ghost:hover{background:var(--teal-l);color:var(--teal-d)}
.btn-gold{background:var(--gold-2);border-color:var(--gold-2);color:var(--navy)}
.btn-gold:hover{background:#f2c46a;border-color:#f2c46a;color:var(--navy)}
.btn-sm{padding:8px 16px;font-size:.94rem}
.btn-lg{padding:15px 30px;font-size:1.1rem}
.link{font-weight:600;text-decoration:none;font-size:.94rem}

/* hero */
.hero{background:linear-gradient(180deg,#fff 0%,var(--bg) 100%);padding:64px 0 56px;border-bottom:1px solid var(--line-2)}
.hero-grid,.game-grid{display:grid;grid-template-columns:1.1fr .9fr;gap:48px;align-items:center}
.eyebrow{color:var(--gold);font-weight:700;text-transform:uppercase;letter-spacing:.08em;font-size:.82rem;margin-bottom:.8em}
.lead{font-size:1.15rem;color:var(--ink-2);max-width:40em}
.hero-actions{display:flex;flex-wrap:wrap;gap:12px;margin-top:22px}
.hero-art,.game-art{border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow);border:1px solid var(--line-2);aspect-ratio:16/10}
.hero-art svg,.game-art svg{width:100%;height:100%}

/* sections */
.section{padding:56px 0}
.section-alt{background:var(--panel);border-top:1px solid var(--line-2);border-bottom:1px solid var(--line-2)}
.section-head{margin-bottom:28px}
.section-head p{color:var(--muted);margin:0}
.page-head{background:#fff;border-bottom:1px solid var(--line-2);padding:52px 0 40px}
.game-head{padding:40px 0 48px}
.crumbs{font-size:.92rem;color:var(--muted);margin-bottom:14px}
.crumbs a{text-decoration:none;font-weight:600}
.crumbs span{margin:0 4px}
.note{margin-top:14px;font-size:.94rem;color:var(--muted)}

/* cards */
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(310px,1fr));gap:24px}
.card{background:var(--panel);border:1px solid var(--line-2);border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow);display:flex;flex-direction:column;transition:transform .15s,box-shadow .15s}
.card:hover{transform:translateY(-2px);box-shadow:0 2px 4px rgba(18,38,63,.06),0 10px 28px rgba(18,38,63,.1)}
.card-thumb{display:block;aspect-ratio:16/9;border-bottom:1px solid var(--line-2)}
.card-thumb svg{width:100%;height:100%}
.card-body{padding:20px 22px 22px;display:flex;flex-direction:column;flex:1}
.card-body h3 a{color:var(--navy);text-decoration:none}
.card-body h3 a:hover{color:var(--teal)}
.card-body>p{color:var(--ink-2);font-size:.97rem}
.card-kicker{color:var(--teal);font-weight:700;font-size:.8rem;text-transform:uppercase;letter-spacing:.06em;margin-bottom:6px}
.card-actions{margin-top:auto;display:flex;align-items:center;gap:16px;padding-top:6px}
.tags{list-style:none;padding:0;margin:0 0 16px;display:flex;flex-wrap:wrap;gap:6px}
.tags li{background:var(--bg-2);color:var(--ink-2);font-size:.8rem;font-weight:600;padding:4px 10px;border-radius:99px}
.tags li:first-child{background:var(--gold-l);color:#7a520b}

/* thumbnails */
.t-bg{fill:#f7fafc}
.t-grid line{stroke:#dde5ee;stroke-width:1}
.t-axis{stroke:#9aabbe;stroke-width:1.6}
.t-pt{fill:var(--teal)}
.t-pt2{fill:#fff;stroke:var(--teal);stroke-width:2.5}
.t-line{stroke:var(--teal);stroke-width:3;stroke-linecap:round}
.t-route{fill:none;stroke:var(--gold);stroke-width:3;stroke-dasharray:8 6;stroke-linecap:round}
.t-gold{fill:var(--gold-2);stroke:var(--gold);stroke-width:2}
.t-goldline{fill:none;stroke:var(--gold);stroke-width:2}
.t-dash{fill:none;stroke:#7d8fa5;stroke-width:1.8;stroke-dasharray:5 5}
.t-tri{fill:rgba(232,176,75,.25);stroke:var(--gold);stroke-width:2}
.t-bld{fill:#c8d6e3;stroke:#9aabbe}
.t-obj{fill:rgba(18,94,120,.22);stroke:var(--teal);stroke-width:2.5}
.t-img{fill:rgba(181,125,24,.18);stroke:var(--gold);stroke-width:2.5;stroke-dasharray:7 5}
.t-arrow{fill:none;stroke:#7d8fa5;stroke-width:2;stroke-dasharray:4 5}
.t-poly{fill:rgba(18,94,120,.14);stroke:var(--teal);stroke-width:2.5}
.t-circ{fill:rgba(18,94,120,.1);stroke:var(--teal);stroke-width:3}
.t-tan{stroke:var(--gold);stroke-width:3;stroke-linecap:round}

/* features */
.features{display:grid;grid-template-columns:repeat(4,1fr);gap:28px}
.features p{color:var(--ink-2);margin:0}
.features h3{color:var(--navy)}
@media (max-width:1100px){.features{grid-template-columns:repeat(2,1fr)}}

/* band */
.band{background:var(--navy);color:#fff;padding:44px 0}
.band-row{display:flex;align-items:center;justify-content:space-between;gap:32px}
.band h2{color:#fff;font-size:1.5rem}
.band p{color:#c9d6e4;margin:0;max-width:40em}

.coming{list-style:none;padding:0;margin:0;display:flex;flex-wrap:wrap;gap:10px}
.coming li{border:1.5px dashed var(--line);color:var(--muted);padding:8px 16px;border-radius:99px;font-weight:600;font-size:.95rem;background:#fff}

/* game page */
.two-col{display:grid;grid-template-columns:1fr 1fr;gap:48px}
.checks{list-style:none;padding:0;margin:0}
.checks li{position:relative;padding:10px 0 10px 34px;border-bottom:1px solid var(--line-2)}
.checks li::before{content:"";position:absolute;left:4px;top:15px;width:18px;height:18px;border-radius:50%;background:var(--teal-l) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16'%3E%3Cpath d='M4 8.5l2.5 2.5L12 5.5' fill='none' stroke='%23125e78' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E") center/14px no-repeat}
.modes{display:grid;gap:12px;margin-bottom:20px}
.mode{background:#fff;border:1px solid var(--line-2);border-left:4px solid var(--teal);border-radius:10px;padding:14px 18px}
.mode h3{margin:0 0 2px;font-size:1.02rem}
.mode p{margin:0;color:var(--ink-2);font-size:.96rem}
.teacher-box{background:var(--gold-l);border-radius:12px;padding:18px 20px}
.teacher-box h3{font-size:1.02rem;margin-bottom:4px}
.teacher-box p{margin:0;font-size:.96rem;color:#4a3a14}

/* resources */
.store-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:24px}
.store{background:#fff;border:1px solid var(--line-2);border-radius:var(--radius);padding:30px;box-shadow:var(--shadow)}
.store p{color:var(--ink-2)}
.store-soon{background:var(--bg-2);box-shadow:none}

.prose h2{margin-top:1.6em;font-size:1.35rem}
.prose p{color:var(--ink-2)}

/* footer */
.site-foot{background:#0e1e32;color:#b9c7d6;padding:48px 0 24px;font-size:.95rem}
.foot-grid{display:grid;grid-template-columns:2fr 1fr 1fr;gap:32px}
.site-foot h2{color:#fff;font-size:.95rem;text-transform:uppercase;letter-spacing:.06em}
.site-foot ul{list-style:none;padding:0;margin:0}
.site-foot li{margin-bottom:6px}
.site-foot a{color:#dbe6f0;text-decoration:none}
.site-foot a:hover{color:#fff;text-decoration:underline}
.brand-foot{color:#fff;margin-bottom:12px}
.foot-base{border-top:1px solid #243a55;margin-top:32px;padding-top:18px;font-size:.85rem;color:#8ea2b8}

@media (max-width:860px){
  .hero-grid,.game-grid,.two-col,.store-grid{grid-template-columns:1fr;gap:32px}
  .hero{padding:40px 0}
  .features{grid-template-columns:1fr;gap:22px}
  .band-row{flex-direction:column;align-items:flex-start}
  .foot-grid{grid-template-columns:1fr 1fr}
  .foot-grid>div:first-child{grid-column:1/-1}
}
@media (max-width:520px){
  body{font-size:16px}
  .wrap{padding:0 16px}
  .brand span{font-size:1.05rem}
  .head-row{gap:8px}
  .nav{gap:0}
  .nav a{padding:8px 7px;font-size:.9rem}
  .logo-mark{width:28px;height:28px}
  .cards{grid-template-columns:1fr}
  .hero-art{display:none}
}
/* exam-level labels and filter */
.tags li.lv{background:var(--teal-l);color:var(--teal-d)}
.tags li.lv-igcse-c,.tags li.lv-igcse-e{background:var(--gold-l);color:#7a520b}
.tags li:first-child{background:inherit}
.tags li.lv:first-child{background:var(--teal-l)}
.tags li.lv-igcse-c:first-child,.tags li.lv-igcse-e:first-child{background:var(--gold-l)}
.tags li.age{background:var(--bg-2);color:var(--ink-2)}
.filter{display:flex;flex-wrap:wrap;gap:8px;align-items:center}
.filter-lab{font-weight:700;color:var(--ink-2);margin-right:4px}
.chip-btn{border:1.5px solid var(--line);background:#fff;color:var(--ink);border-radius:99px;padding:7px 14px;font:600 .95rem var(--font);cursor:pointer}
.chip-btn:hover{border-color:var(--teal)}
.chip-btn.on{background:var(--navy);border-color:var(--navy);color:#fff}
.filter-note{color:var(--muted);margin:10px 0 0;min-height:1.2em}
.card[hidden],section[hidden]{display:none!important}

/* long-form game pages */
.narrow-wide{max-width:960px}
.tbl-wrap{overflow-x:auto}
table.refs{width:100%;border-collapse:collapse;background:#fff;border-radius:12px;overflow:hidden;font-size:.97rem}
table.refs th,table.refs td{text-align:left;padding:11px 14px;border-bottom:1px solid var(--line-2);vertical-align:top}
table.refs th{background:var(--navy);color:#fff;font-weight:700}
.examples{display:grid;gap:16px}
.example{background:#fff;border:1px solid var(--line-2);border-left:4px solid var(--gold);border-radius:12px;padding:18px 22px}
.example h3{font-size:1.08rem;line-height:1.4}
.example ol{margin:8px 0;padding-left:22px;color:var(--ink-2)}
.example .ans{font-weight:700;color:var(--teal-d);margin:0}
ul.mistakes{padding-left:20px;margin:0}
ul.mistakes li{margin:8px 0;color:var(--ink-2)}
ul.mistakes b{color:var(--ink)}
details.faq{background:#fff;border:1px solid var(--line-2);border-radius:12px;padding:14px 18px;margin-bottom:10px}
details.faq summary{font-weight:700;cursor:pointer}
details.faq p{margin:10px 0 0;color:var(--ink-2)}

/* brand logo image */
.logo-mark{width:40px;height:40px;border-radius:50%;display:block}
.nowrap{white-space:nowrap}
@media (max-width:520px){.logo-mark{width:34px;height:34px}}

/* column vectors in page text */
.cv{display:inline-flex;flex-direction:column;align-items:center;vertical-align:middle;line-height:1.1;padding:1px .4em;margin:0 .15em;border-left:1.6px solid currentColor;border-right:1.6px solid currentColor;border-radius:.55em;font-size:.88em}

/* resource product cards */
.prod-section{padding:36px 0 8px}
.prods{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:18px}
.prod{background:#fff;border:1px solid var(--line-2);border-top:4px solid var(--gold-2);border-radius:var(--radius);box-shadow:var(--shadow);padding:18px 20px;display:flex;flex-direction:column}
.prod h3{font-size:1.08rem;color:var(--navy);margin-bottom:6px}
.prod-blurb{color:var(--ink-2);font-size:.95rem}
.prod .tags{margin-bottom:10px}
.prod-game{font-size:.92rem;margin:0 0 12px;color:var(--ink-2)}
.prod-game a{font-weight:700}
.prod-actions{margin-top:auto;display:flex;gap:10px;flex-wrap:wrap}
.prod[hidden],.prod-section[hidden]{display:none!important}

/* header fits four menu items on phones */
@media (max-width:480px){.site-head .brand span{display:none}.nav a{padding:8px 7px;font-size:.92rem}}
@media (max-width:360px){.head-row{gap:4px}.nav a{padding:8px 5px;font-size:.86rem}.logo-mark{width:30px;height:30px}}

/* ---------- revision articles ---------- */
.article{font-size:1.04rem}
.article h2{margin-top:1.8em}
.article p,.article li{color:var(--ink-2)}
.article ul,.article ol{padding-left:22px}
.article .example{margin:18px 0}
.article .example ol{padding-left:22px}
.article table.refs{font-size:.95rem}
.art-meta{color:var(--muted);font-size:.92rem;margin-top:10px}
svg.dg{width:100%;max-width:380px;height:auto;margin:12px 0 6px;border:1px solid var(--line-2);border-radius:10px}
.dg-l{font:800 17px var(--font);fill:var(--navy);text-anchor:middle}
.dg-n{font:600 11px var(--font);fill:#7d8fa5;text-anchor:middle}
.dg-c{font:700 13px var(--font);fill:var(--teal-d)}
.cta-box{background:var(--teal-l);border:1px solid #c5e0ea;border-radius:var(--radius);padding:22px 24px;margin:32px 0}
.cta-box h2,.cta-box h3{margin-top:0}
.cta-box p{margin:0 0 14px}
.art-list{display:grid;gap:18px}
.art-card{background:#fff;border:1px solid var(--line-2);border-radius:var(--radius);padding:20px 22px;box-shadow:var(--shadow)}
.art-card h3 a{color:var(--navy);text-decoration:none}
.art-card h3 a:hover{color:var(--teal)}
.art-card p{color:var(--ink-2);margin:0 0 12px}
.guide-link{background:#fff;border:1px solid var(--line-2);border-left:4px solid var(--gold);border-radius:12px;padding:16px 20px;margin-top:20px}
.guide-link p{margin:0}
.formula{font-weight:700;color:var(--navy);font-size:1.1rem}
.formula-box{background:#fff;border:1px solid var(--line-2);border-left:4px solid var(--teal);border-radius:12px;padding:14px 20px;margin:14px 0}
.formula-box p{margin:6px 0;color:var(--ink);font-size:1.08rem}
table.refs-sm{max-width:360px}
svg.dg-sector{max-width:260px}