:root{--bg:#e8f3fd;--card:#fff;--tx:#0b214a;--navy:#0b214a;--b:#2496ed;--bd:#1d63ed;--bt:#fff;--sky:#d4e9fb;--ln:#a9d0f5;--ok:#0e7a4b;--cd:#0b4fb3;--f:#0b214a;--r:18px;color-scheme:light dark}
@media(prefers-color-scheme:dark){:root:not([data-theme=light]){--bg:#0a1730;--card:#112a52;--tx:#e6f1ff;--bd:#4aaef5;--bt:#071a38;--sky:#1a3a6b;--ln:#2a5190;--ok:#52d99b;--cd:#7cc4ff;--f:#ffd166}}
:root[data-theme=dark]{--bg:#0a1730;--card:#112a52;--tx:#e6f1ff;--bd:#4aaef5;--bt:#071a38;--sky:#1a3a6b;--ln:#2a5190;--ok:#52d99b;--cd:#7cc4ff;--f:#ffd166}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--tx);font:clamp(1rem,.95rem + .3vw,1.18rem)/1.65 system-ui,"Segoe UI",Roboto,sans-serif}
h1,h2,h3{letter-spacing:-.02em;font-weight:800}
.skip{position:absolute;left:-999px}
.skip:focus{left:8px;top:8px;z-index:9;background:#fff;color:var(--navy);padding:.6rem 1rem;border-radius:10px;border:3px solid var(--b)}
header{background:var(--navy);color:#fff}
.hw{display:flex;flex-wrap:wrap;gap:.8rem 2rem;justify-content:space-between;align-items:center;max-width:70rem;margin:0 auto;padding:1.2rem clamp(1rem,4vw,2rem) .8rem}
h1{margin:0;font-size:clamp(1.8rem,5vw,2.8rem);line-height:1.1}
header p{margin:.2rem 0}
.hp{display:grid;gap:.4rem;min-width:min(100%,16rem)}
.bt{font-weight:800;color:#8fd0ff}
progress{width:100%;height:1.1rem;accent-color:#2496ed}
.wave{height:22px;background:var(--bg) url("data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' width='60' height='22'><path d='M0 0h60v6C50 6 50 22 30 22S10 6 0 6z' fill='%230b214a'/></svg>") repeat-x}
nav{max-width:56rem;margin:0 auto;padding:.4rem clamp(1rem,4vw,2rem)}
summary{cursor:pointer;font-weight:800;min-height:44px;display:flex;align-items:center}
#nav{list-style:none;margin:.5rem 0;padding:0;display:grid;grid-template-columns:repeat(auto-fill,minmax(min(100%,10rem),1fr));gap:.6rem}
#nav button{width:100%;height:100%;min-height:44px;display:grid;gap:.1rem;text-align:left;padding:.6rem .8rem;font:inherit;font-size:.92rem;line-height:1.3;color:var(--tx);background:var(--card);border:2px solid var(--ln);border-radius:12px;cursor:pointer;overflow-wrap:anywhere}
#nav button:hover{border-color:var(--b)}
#nav button b{font-size:1.5rem}
#nav button[aria-current=page]{background:var(--bd);border-color:var(--bd);color:var(--bt);font-weight:800}
main{max-width:56rem;margin:0 auto;padding:1rem clamp(1rem,4vw,2rem) 2rem}
h2{font-size:clamp(1.5rem,4.5vw,2.3rem);line-height:1.2;margin:.3rem 0 1rem}
h3{font-size:1.35rem;margin:2.2rem 0 .3rem}
h4{margin:1rem 0 .3rem}
.sub{margin:0 0 .8rem}
.story{background:var(--card);border:2px solid var(--ln);border-left:10px solid var(--b);border-radius:var(--r);padding:1rem 1.3rem;box-shadow:0 6px 18px rgba(11,33,74,.1)}
.story strong{color:var(--cd)}
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(min(100%,15rem),1fr));gap:1rem}
.card,.opt,.btn{font:inherit;color:var(--tx);cursor:pointer;transition:transform .15s,box-shadow .15s}
.card:hover,.btn:hover{transform:translateY(-2px)}
.card{min-height:7.5rem;display:grid;place-items:center;text-align:center;padding:1.3rem 1rem 1rem;border:2px solid var(--ln);border-radius:10px;box-shadow:0 6px 14px rgba(11,33,74,.12);background:linear-gradient(var(--b) 0 .5rem,transparent .5rem),repeating-linear-gradient(90deg,var(--sky) 0 3px,var(--card) 3px 12px)}
.card>*{background:var(--card);padding:.1rem .5rem;border-radius:6px}
.card[aria-pressed=true]{background:var(--b);color:var(--navy);border-color:var(--bd)}
.card[aria-pressed=true]>*{background:transparent}
code{font-family:ui-monospace,Consolas,monospace;color:var(--cd);font-size:1.03em;font-weight:700;overflow-wrap:anywhere}
.match{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,17rem),1fr));gap:0 1.2rem}
.opt{display:block;width:100%;min-height:44px;margin:.5rem 0;text-align:left;background:var(--card);padding:.55rem 1rem;border:2px solid var(--ln);border-radius:12px}
.opt:hover:not(:disabled){border-color:var(--b)}
.opt[aria-pressed=true]{background:var(--b);color:var(--navy);border-color:var(--bd)}
.opt.ok{background:var(--ok);color:#fff;border-color:var(--ok)}
.opt.ok::after{content:" ✅"}
.opt:disabled{cursor:default}
.msg{min-height:1.7em;margin:.3rem 0;font-weight:800}
.qz{border:2px solid var(--ln);border-radius:var(--r);margin:0 0 1rem;padding:.6rem 1rem;background:var(--card)}
legend{font-weight:800;padding:0 .5rem;color:var(--cd)}
.ord{padding-left:1.4rem}
.term{background:#071428;color:#d6ecff;border-radius:var(--r);padding:1rem;font-family:ui-monospace,Consolas,monospace;border:2px solid var(--b)}
.term label{display:block;color:#b5cbe6}
.mis{margin:0 0 .5rem;color:#8fd0ff;font-weight:700}
.log{min-height:4rem;max-height:15rem;overflow:auto;margin:.5rem 0}
.log div{white-space:pre-wrap;overflow-wrap:anywhere}
.log .ok{color:#6ee79b}.log .bad{color:#ffa08a}.log .hint{color:#8fd0ff}
.row{display:flex;flex-wrap:wrap;gap:.5rem;align-items:center}
.ps{color:#0db7ed;font-weight:800}
.row input{flex:1 1 10rem;min-width:0;min-height:44px;padding:.4rem .7rem;font:inherit;color:#fff;background:#0f2447;border:2px solid #2496ed;border-radius:10px}
.btn{min-height:44px;padding:.5rem 1.2rem;border:0;border-radius:999px;background:var(--bd);color:var(--bt);font-weight:800}
.btn.alt{background:transparent;color:inherit;border:2px solid currentColor}
header .btn.alt{color:#fff}
.btn:disabled{opacity:.5;cursor:default}
.goals{list-style:none;padding:0}.goals li{margin:.35rem 0}
.pn{display:flex;flex-wrap:wrap;justify-content:space-between;gap:1rem;margin:2rem 0}
.pn .btn.alt{color:var(--tx)}
footer{padding:1rem 1rem 5rem;text-align:center}
#toast{position:fixed;left:50%;bottom:1rem;max-width:90vw;transform:translate(-50%,200%);background:var(--navy);color:#fff;border:2px solid var(--b);border-radius:999px;padding:.6rem 1.4rem;font-weight:800;box-shadow:0 8px 20px rgba(0,0,0,.3);transition:transform .3s}
#toast.show{transform:translate(-50%,0)}
:focus-visible{outline:4px solid var(--f);outline-offset:3px}
header :focus-visible{outline-color:#ffd166}
@media(prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important}}
summary::after{content:"▾";margin-left:.6rem;font-size:1.2em}
details[open]>summary::after{content:"▴"}
summary::-webkit-details-marker{display:none}