/* Roji Number Explorer.
   Layout: Roji brand header, two tabs, then choices on the left and the chart or block mat on the right (stacked on phones). */
:root{
  --navy:#1D5B8D; --sky:#0B7CC9; --green:#3CC47C; --green-ink:#1E8A52;
  --bg:#EEF5FB; --surface:#FFFFFF; --ink:#16324A; --muted:#557089; --line:#CFE0EE; --field:#F7FBFE; --tint:#E3EFF9;
  --on-navy:#FFFFFF; --warn-bg:#FFF1CC; --warn-ink:#7A5400; --ok-bg:#DDF5E8; --ok-ink:#15693F;
  --a:#0B7CC9; --a-ink:#FFFFFF; --b:#3CC47C; --b-ink:#06301B;
  --pick:#FFEBA8; --pick-ink:#5C3F00; --pick-line:#B97A00;
  --bad-bg:#FFE1D6; --bad-ink:#8A2A0B;
  --block:#F4B63F; --block-line:#9A6400; --block-top:#FFD98A;
  --title-fill:#0B7CC9; --title-stroke:#12344F;
  --shadow:0 1px 0 #d7e6f2, 0 10px 30px -18px rgba(29,91,141,.45);
  --f-display:"Luckiest Guy","Arial Rounded MT Bold","Trebuchet MS",sans-serif;
  --f-body:"Nunito",system-ui,-apple-system,"Segoe UI",sans-serif;
  color-scheme:light;
}
@media (prefers-color-scheme: dark){:root:not([data-theme="light"]){
  --bg:#0E1B27; --surface:#15283A; --ink:#E6F0F8; --muted:#9BB3C8; --line:#27425A; --field:#10202F; --tint:#1B3247;
  --navy:#5CADE2; --sky:#5CADE2; --green-ink:#5FD897; --on-navy:#06121C;
  --warn-bg:#3B3013; --warn-ink:#F4CF6E; --ok-bg:#153B2A; --ok-ink:#7FE3AE;
  --a:#5CADE2; --a-ink:#06121C; --b:#3CC47C; --b-ink:#06301B;
  --pick:#4A3B10; --pick-ink:#FBE39B; --pick-line:#F4CF6E;
  --bad-bg:#4A1F12; --bad-ink:#FFB59C;
  --block:#D9A032; --block-line:#5C3F00; --block-top:#F2C566;
  --title-fill:#5CADE2; --title-stroke:#06121C; --shadow:0 12px 30px -20px rgba(0,0,0,.8); color-scheme:dark}}
:root[data-theme="dark"]{
  --bg:#0E1B27; --surface:#15283A; --ink:#E6F0F8; --muted:#9BB3C8; --line:#27425A; --field:#10202F; --tint:#1B3247;
  --navy:#5CADE2; --sky:#5CADE2; --green-ink:#5FD897; --on-navy:#06121C;
  --warn-bg:#3B3013; --warn-ink:#F4CF6E; --ok-bg:#153B2A; --ok-ink:#7FE3AE;
  --a:#5CADE2; --a-ink:#06121C; --b:#3CC47C; --b-ink:#06301B;
  --pick:#4A3B10; --pick-ink:#FBE39B; --pick-line:#F4CF6E;
  --bad-bg:#4A1F12; --bad-ink:#FFB59C;
  --block:#D9A032; --block-line:#5C3F00; --block-top:#F2C566;
  --title-fill:#5CADE2; --title-stroke:#06121C; --shadow:0 12px 30px -20px rgba(0,0,0,.8); color-scheme:dark}

*{box-sizing:border-box}
[hidden]{display:none!important}
body{margin:0;background:var(--bg);color:var(--ink);font-family:var(--f-body);font-size:16px;line-height:1.5;-webkit-text-size-adjust:100%}
.wrap{max-width:1180px;margin:0 auto;padding-inline:clamp(16px,3vw,32px);padding-block:12px 40px}
button,input,select{font-family:inherit}
:focus-visible{outline:3px solid var(--green);outline-offset:2px}
p{margin:0}
.sr{position:absolute;width:1px;height:1px;overflow:hidden;clip-path:inset(50%)}

/* ---------- brand header (same on every Roji tool) ---------- */
.brandbar{display:flex;justify-content:space-between;align-items:center;gap:12px;font-weight:800;color:var(--navy);font-size:.9rem}
.brandbar a{color:inherit;text-decoration:none}
.brandbar .kit{letter-spacing:.08em;text-transform:uppercase;font-size:.72rem;color:var(--muted)}
.hero{display:flex;align-items:center;margin-block:4px 10px}
.hero-text{flex:1;min-width:0;padding-bottom:clamp(8px,2vw,20px)}
.eyebrow{font-weight:800;color:var(--green-ink);letter-spacing:.08em;text-transform:uppercase;font-size:.78rem}
h1{font-family:var(--f-display);font-weight:400;font-size:clamp(2.1rem,6vw,3.8rem);line-height:.95;margin:4px 0 10px;
  color:var(--title-fill);-webkit-text-stroke:2px var(--title-stroke);paint-order:stroke fill;letter-spacing:.01em;text-wrap:balance;text-shadow:0 3px 0 var(--title-stroke)}
h1 .grades{display:inline-block;font-size:.5em;line-height:1.1;-webkit-text-stroke:1.5px var(--title-stroke);text-shadow:0 2px 0 var(--title-stroke);white-space:nowrap}
.tagline{color:var(--muted);font-weight:700;max-width:52ch}
.roji{flex:0 0 auto;width:clamp(110px,20vw,200px);display:block}
.roji img{width:100%;height:auto;display:block;filter:drop-shadow(0 8px 12px rgba(18,52,79,.18))}

/* ---------- tabs ---------- */
.tabs{display:flex;gap:8px;margin-bottom:16px;flex-wrap:wrap}
.tabs button{flex:1 1 150px;font-family:var(--f-display);font-size:1.15rem;letter-spacing:.02em;line-height:1.1;padding:.7em .8em .5em;min-height:52px;
  border:2px solid var(--navy);border-radius:14px;background:var(--surface);color:var(--navy);cursor:pointer}
.tabs button[aria-selected="true"]{background:var(--navy);color:var(--on-navy)}

/* ---------- layout ---------- */
.app{display:grid;grid-template-columns:minmax(0,340px) minmax(0,1fr);gap:20px;align-items:start}
@media (max-width:900px){.app{grid-template-columns:minmax(0,1fr)}}
.panel{background:var(--surface);border-radius:18px;box-shadow:var(--shadow);padding:6px 20px 20px;min-width:0}
.stage{display:grid;gap:14px;min-width:0}
.grp{padding-top:14px;display:grid;gap:10px}
.grp+.grp{border-top:2px dashed var(--line);margin-top:16px}
.grp h2,.rtitle{font-size:.78rem;text-transform:uppercase;letter-spacing:.08em;color:var(--green-ink);margin:0;font-weight:800}
label{display:grid;gap:4px;font-size:.85rem;font-weight:800;color:var(--muted)}
.hint{font-weight:600;font-size:.82rem;color:var(--muted)}
.lbl{font-size:.85rem;font-weight:800;color:var(--muted);margin-bottom:6px}
input[type="number"],input[type="text"]{font-size:1.1rem;font-weight:800;color:var(--ink);background:var(--field);border:2px solid var(--line);border-radius:10px;padding:9px 10px;width:100%;min-width:0;min-height:44px}
input:focus{border-color:var(--sky)}
.seg{display:flex;flex-wrap:wrap;gap:6px}
.seg button{font-size:.9rem;font-weight:800;border:2px solid var(--line);background:var(--surface);color:var(--ink);border-radius:999px;padding:8px 13px;min-height:44px;min-width:44px;cursor:pointer}
.seg.nums button{padding-inline:6px;font-size:1rem;font-variant-numeric:tabular-nums}
.seg button[aria-pressed="true"]{background:var(--navy);color:var(--on-navy);border-color:var(--navy)}
.check{display:flex;align-items:center;gap:10px;font-weight:700;color:var(--ink);font-size:.95rem}
.check input{width:24px;height:24px;flex:none;accent-color:var(--green)}
.btn{display:inline-flex;align-items:center;justify-content:center;font-size:.95rem;font-weight:800;border:2px solid var(--navy);background:var(--navy);color:var(--on-navy);
  border-radius:12px;padding:9px 16px;min-height:44px;cursor:pointer;text-decoration:none}
.btn.ghost{background:transparent;color:var(--navy)}
.btn.small{font-size:.88rem;padding:6px 12px}
.btn:disabled{opacity:.4;cursor:default}
.actions{display:flex;flex-wrap:wrap;gap:8px}

/* ---------- hundreds chart ---------- */
.chartcard{padding:12px clamp(8px,2vw,18px) 16px;display:grid;gap:12px}
.charthead{display:flex;align-items:center;justify-content:space-between;gap:10px}
.pagename{font-family:var(--f-display);font-size:1.4rem;color:var(--navy);padding-top:.15em;font-variant-numeric:tabular-nums}
.chart{display:grid;grid-template-columns:repeat(10,minmax(0,1fr));gap:clamp(2px,.6vw,5px);max-width:640px;width:100%;margin-inline:auto}
.cell{position:relative;aspect-ratio:1;display:flex;align-items:center;justify-content:center;padding:0;min-width:0;
  font-weight:800;font-size:clamp(.72rem,2.7vw,1.15rem);font-variant-numeric:tabular-nums;
  background:var(--field);color:var(--ink);border:2px solid var(--line);border-radius:22%;cursor:pointer;transition:transform .12s}
.cell.wide{font-size:clamp(.58rem,2.1vw,.95rem);letter-spacing:-.03em}
.cell.a{background:var(--a);color:var(--a-ink);border-color:var(--a)}
.cell.b{background:var(--b);color:var(--b-ink);border-color:var(--b);border-radius:50%}
.cell.a.b{background:linear-gradient(135deg,var(--a) 0 50%,var(--b) 50% 100%);color:var(--a-ink);border-color:var(--ink);border-radius:22%;text-shadow:0 0 3px var(--title-stroke),0 0 3px var(--title-stroke)}
.cell.cross{background:transparent;color:var(--muted);border-style:dashed;text-decoration:line-through;opacity:.55}
.cell.ring{box-shadow:0 0 0 3px var(--surface),0 0 0 6px var(--pick-line);z-index:1}
.cell.pick{background:var(--pick);color:var(--pick-ink);border-color:var(--pick-line)}
.cell.wrong{background:var(--bad-bg);color:var(--bad-ink);border-color:var(--bad-ink);text-decoration:line-through}
.cell.missed{border:3px dashed var(--pick-line)}
.cell.pop{animation:pop .25s ease-out}
@keyframes pop{from{transform:scale(.7)}to{transform:scale(1)}}
.legend{list-style:none;margin:0;padding:0;display:flex;flex-wrap:wrap;gap:6px 16px;justify-content:center;font-size:.85rem;font-weight:700;color:var(--muted)}
.legend:empty{display:none}
.legend li{display:flex;align-items:center;gap:6px}
.legend .cell{width:22px;font-size:0;cursor:default;flex:none}
#tryActions{justify-content:center}

.readout{padding:14px 20px 16px;display:grid;gap:6px}
.rlist{font-weight:800;font-size:1.05rem;font-variant-numeric:tabular-nums;overflow-wrap:anywhere}
.rnote{font-weight:700;color:var(--muted)}
.rlist:empty,.rnote:empty{display:none}
.feedback{border-radius:12px;padding:10px 14px;font-weight:800;background:var(--warn-bg);color:var(--warn-ink)}
.feedback.good{background:var(--ok-bg);color:var(--ok-ink)}

.bubble{position:relative;background:var(--navy);color:var(--on-navy);border-radius:18px;padding:12px 18px 14px;font-weight:800;font-size:1.08rem;max-width:60ch}
.bubble .who{display:block;font-size:.72rem;letter-spacing:.08em;text-transform:uppercase;opacity:.85}

/* ---------- place-value blocks ---------- */
.task{padding:16px 20px;display:grid;gap:12px}
.ask{font-size:1.15rem;font-weight:800}
.ask b{font-family:var(--f-display);font-weight:400;font-size:1.9rem;color:var(--navy);letter-spacing:.02em;vertical-align:-.08em}
.answerrow input{max-width:240px;font-size:1.4rem}
.numcard{padding:14px 20px 16px;display:grid;gap:8px}
.bignum{font-family:var(--f-display);font-size:clamp(2.6rem,10vw,4.2rem);line-height:1;color:var(--navy);padding-top:.12em;font-variant-numeric:tabular-nums}
.forms{margin:0;display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:8px 20px}
.forms dt{font-size:.72rem;text-transform:uppercase;letter-spacing:.08em;font-weight:800;color:var(--green-ink)}
.forms dd{margin:0;font-weight:800;font-size:1.1rem;overflow-wrap:anywhere}

.matcard{padding:12px clamp(8px,2vw,18px) 16px;display:grid;gap:12px}
.mat{--u:clamp(5px,1.35vw,9px);display:grid;grid-auto-flow:column;grid-auto-columns:minmax(0,1fr);gap:clamp(4px,1vw,10px)}
.col{display:grid;grid-template-rows:auto auto minmax(calc(var(--u)*13),1fr) auto auto;gap:6px;background:var(--tint);border-radius:14px;padding:8px clamp(3px,.8vw,8px);min-width:0;text-align:center}
.col h3{margin:0;font-size:clamp(.62rem,2.2vw,.82rem);text-transform:uppercase;letter-spacing:.04em;font-weight:800;color:var(--muted);overflow-wrap:anywhere}
.col .cnt{font-family:var(--f-display);font-size:1.6rem;line-height:1;color:var(--navy);padding-top:.15em}
.col .cnt.over{color:var(--warn-ink);background:var(--warn-bg);border-radius:8px}
.pile{display:flex;flex-wrap:wrap;gap:calc(var(--u)*.45);justify-content:center;align-content:flex-start;padding-top:calc(var(--u)*1.6)}
.blk{flex:none;background-color:var(--block);border:1px solid var(--block-line);
  background-image:linear-gradient(var(--block-line) 1px,transparent 1px),linear-gradient(90deg,var(--block-line) 1px,transparent 1px);
  background-size:var(--u) var(--u);background-position:-1px -1px}
.blk.unit{width:calc(var(--u)*1.5);height:calc(var(--u)*1.5);background-image:none;border-radius:2px}
.blk.rod{width:var(--u);height:calc(var(--u)*10)}
.blk.flat{width:calc(var(--u)*10);height:calc(var(--u)*10);margin-top:calc(var(--u)*-8);border-top:2px solid var(--block-line);box-shadow:0 calc(var(--u)*-.5) 0 var(--block-top),0 calc(var(--u)*-.5) 0 1px var(--block-line)}
.blk.cube{width:calc(var(--u)*10);height:calc(var(--u)*10);margin-top:calc(var(--u)*-6.5);margin-right:calc(var(--u)*1.5);
  box-shadow:calc(var(--u)*.5) calc(var(--u)*-.5) 0 var(--block-top),calc(var(--u)*1) calc(var(--u)*-1) 0 var(--block-top),calc(var(--u)*1.5) calc(var(--u)*-1.5) 0 var(--block-top),calc(var(--u)*1.5) calc(var(--u)*-1.5) 0 1px var(--block-line)}
.pile.flat,.pile.cube{flex-direction:column;flex-wrap:nowrap;align-items:center;padding-top:calc(var(--u)*8.8)}
.blk.new{animation:pop .25s ease-out}
.pm{display:flex;gap:4px;justify-content:center}
.pm button{flex:1 1 0;max-width:56px;min-width:0;min-height:44px;font-size:1.4rem;font-weight:800;line-height:1;border:2px solid var(--navy);border-radius:12px;background:var(--surface);color:var(--navy);cursor:pointer;padding:0}
.pm button.plus{background:var(--navy);color:var(--on-navy)}
.pm button:disabled{opacity:.35;cursor:default}
.swap{display:grid;gap:4px}
.swap button{font-size:clamp(.62rem,2.1vw,.78rem);font-weight:800;line-height:1.15;border:2px solid var(--pick-line);background:var(--pick);color:var(--pick-ink);border-radius:10px;padding:6px 2px;min-height:40px;cursor:pointer;min-width:0;overflow-wrap:anywhere}
.swap button.brk{background:transparent;color:var(--muted);border-color:var(--line)}
.matactions{justify-content:flex-end}

.how{background:var(--surface);border-radius:14px;padding:12px 16px;box-shadow:var(--shadow);margin-top:20px}
.how summary{cursor:pointer;font-weight:800;color:var(--navy)}
.how p{margin-top:8px;max-width:65ch}
.how ul{margin:8px 0 0;padding-left:1.2em;display:grid;gap:4px;max-width:65ch}
footer.site{margin-top:28px;display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap;color:var(--muted);font-size:.85rem;font-weight:700}
footer.site a{color:var(--navy)}
@media (prefers-reduced-motion:reduce){*{transition:none!important;animation:none!important}}