/* Arène CTF — same visual language as sakoi-cyber.me: pure black, faint grid, mono titles */
:root{--bg:#000;--panel:#070708;--panel-2:#0c0c0e;--line:#1c1c20;--line-2:#2a2a30;--fg:#f5f5f7;--muted:#9a9aa3;--dim:#5e5e67;--ok:#7ee2a8;--accent:#a78bfa;
  --display:"Inter Tight",ui-sans-serif,system-ui,sans-serif;--mono:"JetBrains Mono",ui-monospace,Menlo,monospace;color-scheme:dark}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--fg);font-family:var(--display);font-size:16px;line-height:1.6;-webkit-font-smoothing:antialiased}
a{color:inherit;text-decoration:none}
code{font-family:var(--mono);font-size:.9em;background:#141417;border:1px solid var(--line);border-radius:5px;padding:1px 6px}
:focus-visible{outline:1px solid var(--fg);outline-offset:3px;border-radius:8px}
.grid-bg{position:fixed;inset:0;z-index:-1;pointer-events:none;background-image:linear-gradient(rgba(255,255,255,.045) 1px,transparent 1px),linear-gradient(90deg,rgba(255,255,255,.045) 1px,transparent 1px);background-size:34px 34px;
  mask-image:radial-gradient(ellipse 80% 70% at 50% 25%,#000 20%,transparent 100%);-webkit-mask-image:radial-gradient(ellipse 80% 70% at 50% 25%,#000 20%,transparent 100%)}

/* header */
.top{position:sticky;top:0;z-index:20;display:flex;align-items:center;justify-content:space-between;gap:16px;padding:14px max(16px,calc((100% - 1040px)/2));background:rgba(0,0,0,.85);backdrop-filter:blur(10px);border-bottom:1px solid var(--line)}
.brand{display:flex;align-items:center;gap:10px}
.logo{font-family:var(--mono);font-weight:600;font-size:13px;letter-spacing:-.04em;background:var(--fg);color:#000;border-radius:8px;padding:3px 7px}
.bt{display:flex;flex-direction:column;line-height:1.1}
.bt small{font-family:var(--mono);font-size:10px;letter-spacing:.22em;text-transform:uppercase;color:var(--dim)}
.tnav{display:flex;gap:4px;flex-wrap:wrap}
.tnav a{font-family:var(--mono);font-size:13px;color:var(--muted);padding:6px 10px;border-radius:8px}
.tnav a:hover,.tnav a.on{color:var(--fg);background:rgba(255,255,255,.05)}
.tnav a.pf{color:var(--fg);border:1px solid var(--line-2)}

main{max-width:1040px;margin:0 auto;padding:0 16px}
.hero{padding:66px 0 20px}
.hero.small{padding-bottom:6px}
.prompt{display:inline-flex;gap:10px;font-family:var(--mono);font-size:13px;padding:7px 14px;background:#121214;border:1px solid var(--line-2);border-radius:4px;color:#e6e6ea}
.prompt i{font-style:normal;color:var(--muted)}
h1{font-family:var(--mono);font-weight:600;font-size:clamp(32px,6vw,52px);letter-spacing:-.03em;line-height:1.1;margin:20px 0 12px}
.br{color:var(--dim)}
.lead{color:var(--muted);font-size:17px;margin:0;max-width:66ch}
.kicker{display:block;font-family:var(--mono);font-size:11.5px;letter-spacing:.08em;text-transform:uppercase;color:var(--muted)}
.btn{display:inline-flex;align-items:center;gap:8px;height:44px;padding:0 20px;border-radius:12px;font-size:15px;font-weight:600;border:1px solid var(--line-2);background:transparent;color:var(--fg);cursor:pointer;font-family:var(--display)}
.btn.solid{background:var(--fg);color:#000;border-color:var(--fg)}.btn.solid:hover{background:#d8d8dc}
.btn.sm{height:38px;padding:0 15px;font-size:14px}
.btn.ghost{background:transparent;color:var(--muted)}.btn.ghost:hover{color:var(--fg);border-color:var(--muted)}

/* identity */
.ident{margin:26px 0 10px}
.id-card{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:16px;padding:20px 22px;border:1px solid var(--line);border-radius:18px;background:linear-gradient(180deg,var(--panel-2),var(--panel))}
.id-card p{margin:6px 0 0;color:var(--muted);font-size:14px;max-width:60ch}
.id-card.me{border-color:rgba(126,226,168,.3);background:radial-gradient(120% 120% at 0 0,rgba(126,226,168,.06),transparent 55%),linear-gradient(180deg,var(--panel-2),var(--panel))}
.id-card.me b{color:var(--ok)}
.id-form{display:flex;gap:10px;flex-wrap:wrap}
.id-form input{height:44px;padding:0 15px;border-radius:12px;border:1px solid var(--line-2);background:var(--bg);color:var(--fg);font-family:var(--mono);font-size:14px;min-width:180px}
.id-form input:focus{outline:0;border-color:var(--ok)}
.id-actions{display:flex;gap:10px;flex-wrap:wrap}
.id-msg{flex-basis:100%;margin:0;font-family:var(--mono);font-size:12.5px;color:#f87171}

/* filters */
.filters-bar{display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap;margin:30px 0 18px}
.filters{display:flex;flex-wrap:wrap;gap:8px}
.filters button{font-family:var(--mono);font-size:12.5px;color:#cfcfd4;background:transparent;border:1px solid var(--line-2);border-radius:999px;padding:6px 14px;cursor:pointer;text-transform:capitalize}
.filters button.on{background:var(--fg);color:#000;border-color:var(--fg)}
.prog{font-family:var(--mono);font-size:12.5px;color:var(--muted)}

/* board */
.board{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:14px;padding-bottom:40px}
.chal{text-align:left;display:flex;flex-direction:column;gap:12px;padding:20px;border:1px solid var(--line);border-radius:18px;background:linear-gradient(180deg,var(--panel-2),var(--panel));cursor:pointer;color:var(--fg);font-family:var(--display);position:relative;transition:border-color .2s,transform .2s}
.chal:hover{border-color:var(--cat,var(--muted));transform:translateY(-2px)}
.chal-top{display:flex;align-items:center;justify-content:space-between;gap:10px}
.chip{font-family:var(--mono);font-size:11px;text-transform:uppercase;letter-spacing:.05em;color:var(--cat,#cfcfd4);border:1px solid var(--line-2);border-radius:6px;padding:2px 8px}
.chal-pts{font-family:var(--mono);font-size:13px;color:var(--fg)}
.chal h3{margin:0;font-size:18px;letter-spacing:-.01em}
.chal-meta{display:flex;align-items:center;justify-content:space-between;gap:10px;margin-top:auto;font-family:var(--mono);font-size:12px}
.chal-meta .diff{text-transform:capitalize}
.chal-meta .solves{color:var(--dim)}
.chal-st{position:absolute;top:16px;right:16px}
.chal.done{border-color:rgba(126,226,168,.4)}
.chal.done .chal-st{color:#000;background:var(--ok);width:22px;height:22px;border-radius:50%;display:grid;place-items:center;font-size:13px;top:14px;right:14px}
.empty{color:var(--dim);font-family:var(--mono);font-size:13px}

/* modal */
html.modal-open{overflow:hidden}
.modal{position:fixed;inset:0;z-index:40;display:grid;place-items:center;padding:16px;background:rgba(0,0,0,.72);backdrop-filter:blur(6px)}
.modal[hidden]{display:none}
.modal-box{position:relative;width:min(560px,100%);max-height:calc(100svh - 32px);overflow-y:auto;padding:28px;border:1px solid var(--line-2);border-radius:20px;background:linear-gradient(180deg,#0e0e10,#070708)}
.modal-x{position:absolute;top:16px;right:18px;background:none;border:0;color:var(--muted);font-size:16px;cursor:pointer}
.modal-x:hover{color:var(--fg)}
.m-head{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:12px}
.m-head .pts{color:var(--fg)}
.modal-box h2{margin:0 0 2px;font-size:24px;letter-spacing:-.02em}
.m-author{margin:0 0 14px;font-family:var(--mono);font-size:12px;color:var(--dim)}
.m-desc{color:#d4d4d9;line-height:1.7}
.m-files{display:flex;flex-wrap:wrap;gap:10px;margin:16px 0 20px}
.file{display:inline-flex;align-items:center;gap:8px;padding:9px 14px;border:1px solid var(--line-2);border-radius:10px;background:var(--bg);font-family:var(--mono);font-size:13px;color:#dcdce0}
.file:hover{border-color:var(--ok);color:var(--fg)}
.file .fi{color:var(--ok)}
.m-form{display:flex;gap:10px;flex-wrap:wrap}
.m-form[hidden]{display:none}
.m-form input{flex:1 1 220px;min-width:0;height:46px;padding:0 16px;border-radius:12px;border:1px solid var(--line-2);background:var(--bg);color:var(--fg);font-family:var(--mono);font-size:14px}
.m-form input:focus{outline:0;border-color:var(--ok)}
.m-msg{margin:12px 0 0;min-height:1.3em;font-family:var(--mono);font-size:13px}
.m-msg.ok{color:var(--ok)}.m-msg.ko{color:#f87171}
.m-solved{margin:14px 0 0;color:var(--ok);font-family:var(--mono);font-size:14px}
.m-solved[hidden]{display:none}

/* scoreboard */
.sb-wrap{max-width:720px;margin:14px auto 60px}
.sb-head{display:flex;align-items:center;justify-content:space-between;margin-bottom:14px}
.sb{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:8px}
.sb li{display:grid;grid-template-columns:44px 1fr auto auto;gap:14px;align-items:center;padding:14px 18px;border:1px solid var(--line);border-radius:14px;background:linear-gradient(180deg,var(--panel-2),var(--panel))}
.sb li.me{border-color:rgba(126,226,168,.5);background:rgba(126,226,168,.06)}
.sb .r{font-family:var(--mono);color:var(--muted);text-align:center;font-size:15px}
.sb .h{font-weight:600;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.sb .n{font-family:var(--mono);font-size:12px;color:var(--dim)}
.sb .p{font-family:var(--mono);color:var(--ok);font-weight:600}
.sb li.empty{display:block;color:var(--dim);font-family:var(--mono);font-size:13px;text-align:center;background:none;border-style:dashed}

/* doc (rules) */
.doc{max-width:760px;margin:0 auto;padding:10px 0 60px;font-size:16px;line-height:1.8;color:#d4d4d9}
.doc h2{font-family:var(--mono);font-size:19px;color:var(--fg);margin:34px 0 10px}
.doc ul,.doc ol{padding-left:22px;display:flex;flex-direction:column;gap:6px}
.doc .note{padding:14px 18px;border-left:2px solid var(--ok);background:var(--panel-2);border-radius:0 10px 10px 0;color:var(--muted)}
.doc a{color:var(--ok);text-decoration:underline;text-underline-offset:2px}
.doc .back{margin-top:40px}.doc .back a{color:var(--muted)}

/* footer */
.foot{border-top:1px solid var(--line);margin-top:30px;padding:26px max(16px,calc((100% - 1040px)/2));display:flex;flex-wrap:wrap;gap:10px;justify-content:space-between;font-family:var(--mono);font-size:12px;color:var(--dim)}
.foot a{color:var(--muted)}.foot a:hover{color:var(--fg)}

@media (max-width:560px){.sb li{grid-template-columns:34px 1fr auto}.sb .n{display:none}.id-card{flex-direction:column;align-items:flex-start}}
@media (prefers-reduced-motion:reduce){.chal{transition:none}}