/* License-prep engine: shared look for headedin.com/ham, /drone (and the captain app if it wants it). */
:root{--bg:#EEF3F1;--card:#fff;--ink:#0E3B52;--muted:#4A5D66;--rule:#D5DFDB;--magenta:#A3237A;--signal:#E0409F;--lamp:#FFD25A;--tint:#E2ECE8;
  --good:#1E7A4C;--goodbg:#E3F3EA;--bad:#B3261E;--badbg:#FBE9E7;
  --display:"Barlow Condensed","Avenir Next Condensed","Arial Narrow",sans-serif;
  font-family:"Atkinson Hyperlegible",system-ui,-apple-system,"Segoe UI",sans-serif}
*{box-sizing:border-box}
html,body{margin:0;background:var(--bg);color:var(--ink)}
body{overflow-x:hidden;-webkit-text-size-adjust:100%}
a{color:var(--magenta);font-weight:700}
button{font:inherit;color:inherit}
.top{background:var(--ink);color:#fff;position:sticky;top:0;z-index:5;padding-top:env(safe-area-inset-top,0px)}
.top .wrap{display:flex;align-items:center;gap:10px;min-height:54px}
.top .home{color:#fff;text-decoration:none;font-family:var(--display);font-size:1.3rem;letter-spacing:.05em;background:none;border:0;padding:0;cursor:pointer}
.top .home small{color:#9FC0CE;font-size:.8em;letter-spacing:.02em;margin-left:6px}
.top .site{margin-left:auto;color:#CFE0E7;font-size:.9rem;text-decoration:none}
.wrap{max-width:720px;margin:0 auto;padding-inline:16px}
main{padding-block:18px 60px}
h1,h2,h3{font-family:var(--display);font-weight:700;line-height:1.05;margin:0}
h1{font-size:clamp(2.4rem,9vw,3.4rem)}
h2{font-size:1.7rem;margin-bottom:8px}
p,li{line-height:1.55}
.muted{color:var(--muted)}
.card{background:var(--card);border:1px solid var(--rule);border-radius:16px;padding:16px 18px;min-width:0}
.stack{display:grid;gap:12px}
.row{display:flex;gap:10px;flex-wrap:wrap;align-items:center}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:48px;padding:10px 18px;border-radius:12px;border:2px solid var(--ink);
  background:#fff;color:var(--ink);font-family:var(--display);font-weight:700;font-size:1.2rem;letter-spacing:.02em;cursor:pointer;text-decoration:none}
.btn.go{background:var(--signal);border-color:var(--signal);color:#fff}
.btn.dark{background:var(--ink);color:#fff}
.btn.ghost{border-color:var(--rule)}
.btn:disabled{opacity:.45;cursor:default}
.btn.wide{width:100%}
.hero{display:grid;gap:10px;margin-bottom:16px}
.hero p{margin:0;font-size:1.05rem;color:var(--muted)}
.meter{height:12px;border-radius:99px;background:var(--tint);overflow:hidden}
.meter i{display:block;height:100%;background:var(--ink);border-radius:99px;transition:width .3s}
.ready{display:grid;gap:8px}
.ready .big{font-family:var(--display);font-size:2.6rem;font-weight:700;line-height:1}
.ready .big small{font-size:1rem;color:var(--muted);font-family:inherit;font-weight:400;margin-left:6px}
.modes{display:grid;grid-template-columns:1fr 1fr;gap:10px}
.modes .btn{flex-direction:column;min-height:84px;text-align:center;gap:2px}
.modes .btn small{font-family:"Atkinson Hyperlegible",system-ui,sans-serif;font-weight:400;font-size:.82rem;letter-spacing:0;opacity:.85}
.topic{display:grid;grid-template-columns:1fr auto;gap:4px 12px;align-items:center;padding:12px 0;border-top:1px solid var(--rule);cursor:pointer;background:none;border-left:0;border-right:0;border-bottom:0;text-align:left;width:100%}
.topic:first-of-type{border-top:0}
.topic b{font-weight:700}
.topic .n{color:var(--muted);font-size:.9rem}
.topic .meter{grid-column:1/-1;height:6px}
/* question */
.qhead{display:flex;justify-content:space-between;gap:10px;color:var(--muted);font-size:.9rem;margin-bottom:8px}
.qtext{font-size:1.2rem;line-height:1.45;margin:0 0 14px;font-weight:700}
.fig{display:block;width:100%;max-width:420px;margin:0 auto 14px;border:1px solid var(--rule);border-radius:12px;background:#fff;cursor:zoom-in}
.fig.zoom{max-width:none;cursor:zoom-out}
.opts{display:grid;gap:10px}
.opt{display:grid;grid-template-columns:32px 1fr;gap:10px;align-items:start;text-align:left;padding:12px 14px;border-radius:12px;border:2px solid var(--rule);background:#fff;cursor:pointer;line-height:1.45;font-size:1.02rem}
.opt .k{display:grid;place-items:center;width:30px;height:30px;border-radius:50%;background:var(--tint);font-weight:700;font-size:.9rem}
.opt:hover:not(:disabled){border-color:var(--ink)}
.opt.pick{border-color:var(--ink);background:var(--tint)}
.opt.right{border-color:var(--good);background:var(--goodbg)}
.opt.right .k{background:var(--good);color:#fff}
.opt.wrong{border-color:var(--bad);background:var(--badbg)}
.opt.wrong .k{background:var(--bad);color:#fff}
.opt:disabled{cursor:default}
.opt.ot{cursor:default}.opt.ot .rowt{margin:2px 0 8px}.opt.ot .cats{display:flex;flex-wrap:wrap;gap:6px}
.cat{padding:6px 12px;border-radius:999px;border:2px solid var(--rule);background:#fff;cursor:pointer;font:inherit;font-size:.9rem;line-height:1.2}
.cat:hover:not(:disabled){border-color:var(--ink)}.cat.pick{border-color:var(--ink);background:var(--tint)}
.cat.right{border-color:var(--good);background:var(--goodbg)}.cat.wrong{border-color:var(--bad);background:var(--badbg)}.cat:disabled{cursor:default}
.hint{margin:-6px 0 10px}
.scn{margin:0 0 12px;border:1px solid var(--rule);border-radius:14px;background:var(--card);padding:10px 16px}.scn summary{cursor:pointer;font-weight:700;list-style:none;display:flex;justify-content:space-between;align-items:center}.scn summary::-webkit-details-marker{display:none}.scn summary::after{content:'Show';font-weight:400;font-size:.85rem;color:var(--muted)}.scn[open] summary::after{content:'Hide'}.scn .scnp{margin-top:8px;line-height:1.5;white-space:pre-line}.scnp .ph{display:block;margin-top:8px;color:var(--muted);font-size:.85rem;text-transform:uppercase;letter-spacing:.04em}.scnp .ph:first-child{margin-top:0}
.opt.pick .k{background:var(--ink);color:#fff}
.why{margin-top:14px;padding:12px 14px;border-radius:12px;background:var(--tint);line-height:1.5}
.why b{font-family:var(--display);font-size:1.15rem;letter-spacing:.02em}
.why.ok b{color:var(--good)} .why.no b{color:var(--bad)}
.foot{position:sticky;bottom:0;background:linear-gradient(transparent,var(--bg) 30%);padding:16px 0 calc(12px + env(safe-area-inset-bottom,0px));margin-top:12px}
.dots{display:flex;flex-wrap:wrap;gap:4px;margin-bottom:10px}
.dots i{width:10px;height:10px;border-radius:50%;background:var(--rule)}
.dots i.done{background:var(--ink)} .dots i.flag{background:var(--lamp)} .dots i.now{outline:2px solid var(--signal);outline-offset:1px}
/* flashcards */
.flash{min-height:260px;display:grid;place-items:center;text-align:center;cursor:pointer;font-size:1.15rem;line-height:1.5;user-select:none}
.flash .side{font-size:.8rem;color:var(--muted);text-transform:uppercase;letter-spacing:.08em;margin-bottom:8px}
.flash.back{background:var(--goodbg);border-color:var(--good)}
/* results */
.score{font-family:var(--display);font-size:4rem;font-weight:700;line-height:1}
.badge{display:inline-block;font-family:var(--display);font-weight:700;font-size:1.3rem;padding:4px 12px;border-radius:10px}
.badge.pass{background:var(--good);color:#fff} .badge.fail{background:var(--bad);color:#fff}
.miss{border-top:1px solid var(--rule);padding:12px 0}
.miss p{margin:4px 0}
.small{font-size:.88rem}
footer{color:var(--muted);font-size:.85rem;line-height:1.5;padding-block:10px 40px}
@media (max-width:420px){.modes .btn{min-height:76px}.qtext{font-size:1.1rem}}

/* live charts: pan and zoom (prep.js wireChart) */
.lc{position:relative;overflow:hidden;border:1px solid var(--rule);border-radius:12px;background:#fff;margin:0 0 14px;touch-action:none;user-select:none;-webkit-user-select:none;cursor:grab;min-height:120px}
.lc img{position:absolute;left:0;top:0;transform-origin:0 0;max-width:none;-webkit-user-drag:none;pointer-events:none}
.lc.anim img{transition:transform .35s ease}
.lcz{position:absolute;right:8px;top:8px;display:flex;flex-direction:column;gap:6px}
.lcz button{width:40px;height:40px;border-radius:10px;border:1px solid var(--rule);background:rgba(255,255,255,.92);color:var(--ink);font-size:1.3rem;font-weight:700;line-height:1;cursor:pointer}
.lcl{position:absolute;left:8px;bottom:8px;background:rgba(14,59,82,.86);color:#fff;font-size:.8rem;padding:3px 8px;border-radius:8px}
.areas{display:flex;flex-wrap:wrap;gap:8px}
.area{width:44px;height:44px;border-radius:50%;background:#C8302A;color:#fff;border:2px solid #fff;font-weight:700;font-size:1.05rem;box-shadow:0 1px 3px rgba(0,0,0,.35);cursor:pointer}
.area.all{width:auto;padding:0 14px;border-radius:22px;background:var(--ink)}
.ckey{margin:0}.ckey dt{font-weight:700}.ckey dd{margin:0 0 8px;color:var(--muted)}
/* Pass Meter */
.pm{display:grid;gap:8px;border:2px solid var(--ink)}
.pm .pmhead{display:flex;align-items:baseline;justify-content:space-between;gap:8px}
.pm .pmhead h2{margin:0}
.pm .big{font-family:var(--display);font-size:3.2rem;font-weight:700;line-height:1}
.pm .big small{font-size:1rem;color:var(--muted);font-family:inherit;font-weight:400;margin-left:6px}
.pmbar{position:relative;height:14px;overflow:visible}
.pmbar i{background:var(--signal)}
.pmbar b{position:absolute;top:-4px;bottom:-4px;width:3px;background:var(--ink);border-radius:2px}
.pm .topic{margin-top:2px}
.up{color:var(--good);font-weight:700}
.down{color:var(--bad);font-weight:700}
.pmline{margin:0;font-family:var(--display);font-size:1.4rem}
/* Challenge this answer (update160) */
.chl a{font-weight:700}
.chf{display:grid;gap:8px;margin-top:8px;padding:12px;border:1px solid var(--rule);border-radius:12px;background:#fff}
.chf label{display:flex;gap:8px;align-items:flex-start;line-height:1.4}
.chf textarea,.chf input:not([type]){font:inherit;font-size:16px;width:100%;padding:10px;border:1px solid var(--rule);border-radius:10px;color:var(--ink);background:#fff}
.chv.fixed b,.chv.removed b{color:var(--good)} .chv.stands b{color:var(--ink)}
/* Today's 5/10 and Explain as I go (Oct 18) */
.tutor{display:flex;gap:10px;align-items:flex-start;padding:2px 4px;cursor:pointer}
.tutor input{width:20px;height:20px;margin:1px 0 0;flex:none;accent-color:var(--signal)}
.dn{display:inline-flex;gap:6px}
.dn .btn{min-width:52px;padding-left:12px;padding-right:12px}