:root{
  --bg:#0a0c10; --card:#11151c; --line:#1e2530; --fg:#e9edf4; --muted:#8b95a7;
  --green:#3ddc97; --red:#ff5c72; --amber:#ffb454; --blue:#5b8cff; --max:900px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
html,body{min-height:100%}
body{margin:0;min-height:100vh;display:flex;flex-direction:column;
  background:var(--bg);color:var(--fg);
  font:16px/1.65 system-ui,-apple-system,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  -webkit-font-smoothing:antialiased}
code,kbd,pre,.mono{font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace}
a{color:var(--blue)}
.wrap{max-width:var(--max);margin:0 auto;padding:0 22px}

header{border-bottom:1px solid var(--line);background:rgba(10,12,16,.9);
  backdrop-filter:blur(10px);position:sticky;top:0;z-index:40}
header .wrap{display:flex;align-items:center;gap:18px;height:58px}
.brand{font-weight:700;letter-spacing:-.01em;margin-right:auto}
.brand .caret{color:var(--green)}
nav{display:flex;gap:20px;align-items:center}
nav a{color:var(--muted);font-size:.92rem;font-weight:500}
nav a:hover{color:var(--fg);text-decoration:none}
.pill{font-size:.78rem;color:var(--muted);border:1px solid var(--line);
  border-radius:999px;padding:3px 11px}
.pill b{color:var(--green)}

.hero{padding:74px 0 46px}
h1{font-size:clamp(2.1rem,5.5vw,3.3rem);line-height:1.08;letter-spacing:-.03em;margin:0 0 16px;font-weight:800}
h1 .g{color:var(--green)}
.lead{color:var(--muted);font-size:1.1rem;max-width:62ch;margin:0}

section{padding:44px 0;border-top:1px solid var(--line)}
h2{font-size:.76rem;text-transform:uppercase;letter-spacing:.13em;color:var(--muted);
  font-weight:700;margin:0 0 22px}

.rules{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:24px 26px}
.rules ol{margin:0;padding-left:20px;color:var(--muted)}
.rules li{margin:9px 0}
.rules b,.rules strong{color:var(--fg)}

.grid{display:grid;gap:14px;grid-template-columns:repeat(auto-fit,minmax(250px,1fr))}
.card{background:var(--card);border:1px solid var(--line);border-radius:13px;padding:20px;
  display:flex;flex-direction:column;gap:8px;transition:border-color .16s,transform .16s}
.card:hover{border-color:var(--blue);transform:translateY(-2px)}
.card .top{display:flex;align-items:center;gap:10px}
.num{font-size:.78rem;font-weight:700;color:var(--muted);border:1px solid var(--line);
  border-radius:7px;padding:2px 8px}
.card h3{margin:0;font-size:1.02rem;letter-spacing:-.01em}
.card p{margin:0;color:var(--muted);font-size:.9rem}
.diff{margin-left:auto;font-size:.72rem;letter-spacing:.06em;text-transform:uppercase;color:var(--muted)}
.d1{color:var(--green)}.d2{color:var(--blue)}.d3{color:var(--amber)}.d4{color:var(--red)}
.card .go{margin-top:auto;padding-top:6px;font-size:.88rem;font-weight:600}
.card.done{border-color:color-mix(in srgb,var(--green) 40%,var(--line))}
.card.done .num{color:var(--green);border-color:var(--green)}

.brief{background:var(--card);border:1px solid var(--line);border-radius:13px;
  padding:22px 24px;margin-bottom:20px}
.brief p{margin:0 0 10px;color:var(--muted)}
.brief p:last-child{margin:0}
.brief b{color:var(--fg)}

form{display:flex;gap:10px;flex-wrap:wrap;margin-top:4px}
input{flex:1 1 260px;min-width:0;background:var(--bg);color:var(--fg);
  border:1px solid var(--line);border-radius:10px;padding:12px 14px;font-size:.95rem;
  font-family:ui-monospace,SFMono-Regular,Menlo,monospace}
input:focus{outline:none;border-color:var(--blue)}
input.ok{border-color:var(--green)}
input.bad{border-color:var(--red)}
button{font:inherit;cursor:pointer;border-radius:10px;padding:12px 20px;font-weight:600;
  font-size:.92rem;border:1px solid var(--line);background:var(--card);color:var(--fg)}
button.primary{background:var(--green);border-color:var(--green);color:#06231a}
button:hover{border-color:var(--blue)}
button.primary:hover{filter:brightness(1.08);border-color:var(--green)}
button.ghost{font-size:.85rem;padding:9px 15px;color:var(--muted)}

.msg{margin-top:12px;font-size:.92rem;min-height:1.4em;font-weight:500}
.msg.ok{color:var(--green)}
.msg.bad{color:var(--red)}
.hint{margin-top:12px;font-size:.9rem;color:var(--amber);
  background:color-mix(in srgb,var(--amber) 8%,transparent);
  border:1px solid color-mix(in srgb,var(--amber) 30%,transparent);
  border-radius:9px;padding:11px 14px}

nav.crumb{display:flex;gap:14px;align-items:center;font-size:.9rem;color:var(--muted);margin-bottom:18px}

footer{flex-shrink:0;border-top:1px solid var(--line);padding:28px 0 46px;color:var(--muted);font-size:.85rem}
footer .wrap{display:flex;justify-content:space-between;gap:14px;flex-wrap:wrap}

.solved-banner{background:color-mix(in srgb,var(--green) 9%,transparent);
  border:1px solid color-mix(in srgb,var(--green) 35%,transparent);
  border-radius:13px;padding:20px 24px;margin-bottom:22px}
.solved-banner b{color:var(--green)}
@media(max-width:620px){nav a.hide-s{display:none}}

.empty{grid-column:1/-1;background:var(--card);border:1px dashed var(--line);
  border-radius:13px;padding:26px;color:var(--muted);font-size:.92rem;text-align:center}
.empty code{background:var(--bg);border:1px solid var(--line);border-radius:6px;
  padding:2px 6px;font-size:.85rem}
.bar{height:6px;background:var(--card);border:1px solid var(--line);border-radius:999px;overflow:hidden}
.bar span{display:block;height:100%;background:var(--green);transition:width .4s ease}
main{flex:1 0 auto;padding-bottom:20px}
section:first-child{padding-top:52px}

.slots{display:flex;gap:8px;flex-wrap:wrap}
.slot{border:1px solid var(--line);background:var(--card);border-radius:8px;
  padding:6px 13px;font-size:.82rem;color:var(--muted)}
.slot.got{border-color:var(--green);color:var(--green);
  background:color-mix(in srgb,var(--green) 10%,transparent)}
.msg.neutral{color:var(--muted)}
.crumb{display:flex;gap:14px;align-items:center;font-size:.9rem;color:var(--muted);margin-bottom:20px}
h1 .pill{vertical-align:middle;margin-left:10px}

.levels{list-style:none;margin:0;padding:0;background:var(--card);
  border:1px solid var(--line);border-radius:13px;overflow:hidden}
.levels .empty{padding:26px}
.level{display:flex;align-items:center;justify-content:space-between;gap:16px;
  padding:14px 18px;border-bottom:1px solid var(--line)}
.level:last-child{border-bottom:0}
.lvl-name{font-weight:600;letter-spacing:-.01em}
.lvl-count{font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-weight:700;
  font-size:.88rem;border:1px solid;border-radius:8px;padding:3px 11px;min-width:56px;
  text-align:center}
.level.none .lvl-count{color:var(--red);border-color:color-mix(in srgb,var(--red) 45%,transparent);
  background:color-mix(in srgb,var(--red) 10%,transparent)}
.level.part .lvl-count{color:var(--amber);border-color:color-mix(in srgb,var(--amber) 45%,transparent);
  background:color-mix(in srgb,var(--amber) 10%,transparent)}
.level.done .lvl-count{color:var(--green);border-color:color-mix(in srgb,var(--green) 45%,transparent);
  background:color-mix(in srgb,var(--green) 10%,transparent)}

.loginbox{max-width:400px;margin:0 auto;background:var(--card);
  border:1px solid var(--line);border-radius:15px;padding:32px}
.loginbox h1{font-size:1.4rem;margin:0 0 6px}
.loginbox .sub{color:var(--muted);font-size:.9rem;margin:0 0 24px}
.loginbox label{display:block;font-size:.85rem;color:var(--muted);margin-bottom:14px}
.loginbox input{width:100%;margin-top:6px}
.loginbox button{width:100%;margin-top:6px}
.granted{background:#0d1117;border:1px solid var(--green);border-radius:9px;
  padding:12px 14px;margin:14px 0 10px}
.granted code{color:var(--green);font-family:ui-monospace,SFMono-Regular,Menlo,monospace;
  font-size:.95rem;word-break:break-all}
.hint{color:var(--muted);font-size:.86rem;margin:0}

.backlink{display:inline-flex;align-items:center;gap:7px;font-size:.85rem;
  color:var(--muted);text-decoration:none;border:1px solid var(--line);
  border-radius:9px;padding:7px 13px;margin-bottom:22px}
.backlink:hover{color:var(--fg);border-color:var(--blue)}

/* --- 404 --- */
.nf{max-width:560px;margin:0 auto;padding:72px 0 40px;text-align:center}
.nf-code{font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  font-size:clamp(4.5rem,16vw,8rem);line-height:1;font-weight:700;letter-spacing:-.04em;
  margin:0 0 10px;color:transparent;
  background:linear-gradient(180deg,var(--fg) 0%,var(--muted) 100%);
  -webkit-background-clip:text;background-clip:text;
  -webkit-text-fill-color:transparent}
.nf-title{font-size:1.35rem;margin:0 0 10px;letter-spacing:-.02em}
.nf-sub{color:var(--muted);font-size:.95rem;margin:0 auto 30px;max-width:44ch}
.nf-flag{display:inline-block;border:1px dashed var(--green);border-radius:12px;
  padding:16px 26px;background:color-mix(in srgb,var(--green) 7%,transparent);
  margin-bottom:30px}
.nf-flag-label{display:block;font-size:.7rem;letter-spacing:.16em;
  text-transform:uppercase;color:var(--green);margin-bottom:8px}
.nf-flag code{font-size:1.05rem;color:var(--fg);word-break:break-all}
.nf-back{margin-bottom:0}

.na-code{font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  font-size:clamp(1.6rem,5vw,3rem);font-weight:700;letter-spacing:-.02em;
  text-align:center;padding:96px 0 40px;color:var(--red)}
.na-flag{color:var(--fg);border:1px dashed var(--green);border-radius:12px;
  background:color-mix(in srgb,var(--green) 7%,transparent);padding:20px 26px;
  margin:0 auto;max-width:fit-content}

.sub{color:var(--muted);font-size:.92rem}
.notes{list-style:none;margin:0 0 20px;padding:0;border:1px solid var(--line);
  border-radius:13px;overflow:hidden;background:var(--card)}
.note{border-bottom:1px solid var(--line)}
.note:last-child{border-bottom:0}
.note-head{display:flex;align-items:center;gap:14px;width:100%;text-align:left;
  background:none;border:0;padding:15px 18px;color:var(--fg);font-size:.97rem}
.note-head:hover{background:color-mix(in srgb,var(--blue) 7%,transparent)}
.note-title{font-weight:600}
.note-mark{margin-left:auto;color:var(--muted);font-size:1.1rem;line-height:1}
.note-body{padding:0 18px 17px;color:var(--muted);font-size:.92rem}
.note-body p{margin:0}

.game-bar{display:flex;align-items:center;justify-content:space-between;gap:14px;margin:18px 0 6px;flex-wrap:wrap}
.game-bar b{font-size:.95rem}
.game-canvas{display:block;width:100%;height:auto;border:1px solid var(--line);
  border-radius:13px;background:#12151c;image-rendering:pixelated}
.game-report{margin-top:14px;font-size:.92rem;color:var(--muted)}
.game-report a{color:var(--blue)}
.game-report code{background:#1b1f28;border:1px solid var(--line);border-radius:5px;padding:1px 6px}

/* category 06 - mail search */
.searchbar{display:flex;gap:10px;margin:16px 0 8px;flex-wrap:wrap}
.searchbar input{flex:1;min-width:220px}
.row{background:var(--card);border:1px solid var(--line);border-radius:10px;
  padding:13px 15px;margin-bottom:10px}
.row .meta{display:flex;gap:9px;flex-wrap:wrap;color:var(--muted);font-size:.82rem;
  margin-bottom:5px}
.rowtitle{font-weight:600;margin-bottom:3px}
.row .body{color:var(--muted);font-size:.92rem;word-break:break-word}
pre.schema{background:var(--bg);border:1px solid var(--line);border-radius:10px;
  padding:14px 16px;overflow:auto;color:var(--muted);font-size:.84rem;line-height:1.5}

/* category 06 - the hint box */
.hintlink{color:var(--blue);word-break:break-all}