/* Arcadia — design system + game boards. Dark (default) + light. System fonts, no external deps. */
:root{
  --bg:#0b0d13; --bg2:#11141d; --card:#141824; --card2:#1a1f2e; --card3:#1f2638;
  --line:#232a3a; --line2:#2f3850;
  --tx:#eef1f7; --tx2:#aab2c5; --mut:#7b8499;
  --acc:#5b8cff; --acc2:#8b5cf6; --grad:linear-gradient(135deg,#5b8cff,#8b5cf6);
  --ok:#2dd4a7; --live:#ff4d6a; --warn:#ffb020;
  --r:12px; --r2:16px; --r3:22px;
  --sh:0 1px 2px rgba(0,0,0,.3),0 8px 24px rgba(0,0,0,.18);
  --sh2:0 20px 50px -12px rgba(0,0,0,.5);
  --mono:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  --sans:Inter,'Segoe UI',system-ui,-apple-system,Roboto,Helvetica,Arial,sans-serif;
  --max:1100px;
}
[data-theme=light]{
  --bg:#f5f7fb; --bg2:#fff; --card:#ffffff; --card2:#f4f6fb; --card3:#eef1f8;
  --line:#e5e9f1; --line2:#d6dce8;
  --tx:#0d1320; --tx2:#46506a; --mut:#6c7589;
  --sh:0 1px 2px rgba(16,24,40,.06),0 8px 24px rgba(16,24,40,.08);
  --sh2:0 24px 50px -16px rgba(16,24,40,.22);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--tx);font-family:var(--sans);font-size:15px;line-height:1.55;-webkit-font-smoothing:antialiased}
body::before{content:"";position:fixed;inset:0;background:url(/assets/img/grid.svg);opacity:.35;pointer-events:none;z-index:-2}
a{color:inherit;text-decoration:none}
img{max-width:100%;display:block}
h1,h2,h3,h4{margin:0;font-weight:780;letter-spacing:-.02em;line-height:1.15}
.container{max-width:var(--max);margin:0 auto;padding:0 22px}
.muted{color:var(--mut)}
.mono{font-family:var(--mono)}
.center{text-align:center}

/* buttons */
.btn{display:inline-flex;align-items:center;gap:8px;border:0;cursor:pointer;font-family:inherit;font-weight:650;font-size:14px;padding:11px 18px;border-radius:11px;background:var(--grad);color:#fff;transition:.15s;box-shadow:0 6px 18px -6px rgba(91,140,255,.6)}
.btn:hover{transform:translateY(-1px);filter:brightness(1.07)}
.btn.ghost{background:var(--card2);color:var(--tx);border:1px solid var(--line2);box-shadow:none}
.btn.ghost:hover{border-color:var(--acc);background:var(--card3)}
.btn.sm{padding:8px 13px;font-size:13px;border-radius:9px}
.btn.lg{padding:14px 24px;font-size:15px}

/* nav */
header.nav{position:sticky;top:0;z-index:60;background:color-mix(in srgb,var(--bg) 82%,transparent);backdrop-filter:blur(12px);border-bottom:1px solid var(--line)}
.nav-in{display:flex;align-items:center;gap:24px;height:64px}
.brand{display:flex;align-items:center;gap:9px;font-weight:850;font-size:18px;letter-spacing:-.02em}
.brand .mark{width:30px;height:30px;border-radius:9px;background:var(--grad);display:grid;place-items:center;font-size:13px;font-weight:900;color:#fff;box-shadow:0 4px 12px -2px rgba(91,140,255,.6)}
.brand b{color:var(--acc)}
nav.links{display:flex;gap:20px;flex:1}
nav.links a{color:var(--mut);font-weight:600;font-size:14px;padding:6px 0;border-bottom:2px solid transparent;transition:.12s}
nav.links a:hover{color:var(--tx)}
nav.links a.active{color:var(--tx);border-bottom-color:var(--acc)}
.nav-right{display:flex;align-items:center;gap:12px}
.icon-btn{width:36px;height:36px;border-radius:9px;border:1px solid var(--line);background:var(--card);color:var(--tx2);display:grid;place-items:center;cursor:pointer;font-size:15px}
.icon-btn:hover{color:var(--tx);border-color:var(--line2)}
@media(max-width:840px){nav.links{display:none}}

/* hero */
.hero{position:relative;overflow:hidden;border-bottom:1px solid var(--line)}
.hero::before{content:"";position:absolute;inset:0;background:url(/assets/img/hero.svg) center/cover;opacity:.5;z-index:0}
.hero::after{content:"";position:absolute;inset:0;background:radial-gradient(900px 380px at 80% -10%,color-mix(in srgb,var(--acc) 22%,transparent),transparent 70%);z-index:0}
.hero-in{position:relative;z-index:1;text-align:center;max-width:760px;margin:0 auto;padding:64px 0 56px}
.eyebrow{display:inline-flex;align-items:center;gap:8px;font-size:12.5px;font-weight:700;color:var(--acc);background:color-mix(in srgb,var(--acc) 12%,transparent);border:1px solid color-mix(in srgb,var(--acc) 30%,transparent);padding:5px 12px;border-radius:20px;margin-bottom:20px}
.hero h1{font-size:clamp(34px,4.8vw,56px);letter-spacing:-.03em}
.hero h1 .g{background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent}
.hero p.sub{color:var(--tx2);font-size:18px;max-width:540px;margin:18px auto 28px}
.hero-cta{display:flex;gap:12px;flex-wrap:wrap;align-items:center;justify-content:center}
.hero-note{margin-top:16px;color:var(--mut);font-size:13px}

/* band */
.band{border-bottom:1px solid var(--line);background:var(--bg2)}
.band-in{display:grid;grid-template-columns:repeat(4,1fr);gap:20px;padding:26px 0}
.band .v{font-size:26px;font-weight:820;font-family:var(--mono)}
.band .k{color:var(--mut);font-size:12.5px;text-transform:uppercase;letter-spacing:.5px;margin-top:2px}
@media(max-width:680px){.band-in{grid-template-columns:repeat(2,1fr);gap:18px}}

/* sections */
.section{padding:60px 0}
.section.tight{padding:40px 0}
.sec-head{max-width:640px;margin:0 auto 34px;text-align:center}
.sec-head .eyebrow{margin-bottom:14px}
.sec-head h2{font-size:clamp(26px,3.2vw,34px)}
.sec-head p{color:var(--tx2);font-size:16px;margin:12px 0 0}
.sec-head.left{text-align:left;margin-left:0}

/* features */
.features{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}
.feature{background:var(--card);border:1px solid var(--line);border-radius:var(--r2);padding:24px;transition:.15s}
.feature:hover{border-color:var(--line2);transform:translateY(-3px);box-shadow:var(--sh)}
.feature .ic{width:46px;height:46px;border-radius:12px;background:color-mix(in srgb,var(--acc) 14%,transparent);display:grid;place-items:center;margin-bottom:16px;font-size:22px}
.feature h3{font-size:17px;margin-bottom:7px}
.feature p{color:var(--tx2);font-size:14px;margin:0}
@media(max-width:880px){.features{grid-template-columns:repeat(2,1fr)}}
@media(max-width:560px){.features{grid-template-columns:1fr}}

/* steps */
.steps{display:grid;grid-template-columns:repeat(3,1fr);gap:18px;counter-reset:s}
.step{background:var(--card);border:1px solid var(--line);border-radius:var(--r2);padding:26px 22px;position:relative}
.step::before{counter-increment:s;content:counter(s);position:absolute;top:-14px;left:22px;width:34px;height:34px;border-radius:10px;background:var(--grad);color:#fff;font-weight:800;display:grid;place-items:center;box-shadow:0 6px 14px -4px rgba(91,140,255,.6)}
.step h3{font-size:16px;margin:10px 0 6px}.step p{color:var(--tx2);font-size:14px;margin:0}
@media(max-width:760px){.steps{grid-template-columns:1fr}}

/* faq */
.faq{max-width:740px;margin:0 auto;display:flex;flex-direction:column;gap:10px}
.faq details{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:4px 18px}
.faq summary{cursor:pointer;padding:14px 0;font-weight:650;font-size:15px;list-style:none;display:flex;justify-content:space-between;align-items:center}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"+";color:var(--acc);font-size:20px;font-weight:400}
.faq details[open] summary::after{content:"–"}
.faq p{color:var(--tx2);font-size:14px;margin:0 0 16px}

/* cta banner */
.cta{position:relative;overflow:hidden;background:var(--grad);border-radius:var(--r3);padding:48px 40px;text-align:center;color:#fff}
.cta h2{font-size:28px;color:#fff}.cta p{opacity:.92;margin:12px auto 22px;max-width:440px}
.cta .btn{background:#fff;color:#16204a;box-shadow:0 10px 30px -8px rgba(0,0,0,.4)}

/* generic card + page head */
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--r2);padding:20px}
.page-h{padding:30px 0 6px}
.page-h h1{font-size:28px}.page-h p{color:var(--mut);margin:6px 0 0}
.crumb{color:var(--mut);font-size:13px;padding:18px 0 4px}
.crumb a{color:var(--mut)}.crumb a:hover{color:var(--tx)}
.prose{max-width:740px;font-size:15px}
.prose p{color:var(--tx2);margin:14px 0}
.prose h2{font-size:20px;margin:26px 0 8px}

/* ===== game cards ===== */
.gcard-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
.gcard{display:flex;gap:15px;align-items:flex-start;background:var(--card);border:1px solid var(--line);border-radius:var(--r2);padding:18px;transition:.15s}
.gcard:hover{border-color:var(--acc);transform:translateY(-3px);box-shadow:var(--sh)}
.gc-ic{width:50px;height:50px;flex:none;border-radius:13px;background:var(--card2);border:1px solid var(--line2);display:grid;place-items:center;font-size:26px}
.gc-b{min-width:0}
.gc-n{font-weight:730;font-size:16px;display:flex;align-items:center;gap:8px;flex-wrap:wrap}
.gc-t{font-size:10px;font-weight:800;letter-spacing:.5px;text-transform:uppercase;color:var(--acc2);border:1px solid color-mix(in srgb,var(--acc2) 40%,transparent);padding:2px 6px;border-radius:5px}
.gc-d{color:var(--tx2);font-size:13px;margin:4px 0 6px}
.gc-best{color:var(--mut);font-size:12px;font-weight:700;font-family:var(--mono)}
@media(max-width:860px){.gcard-grid{grid-template-columns:repeat(2,1fr)}}
@media(max-width:540px){.gcard-grid{grid-template-columns:1fr}}

/* ===== game play shell ===== */
.ghead{margin:6px 0 18px}
.ghead h1{font-size:26px}
.ghead p{color:var(--mut);margin:6px 0 0}
.gbar{display:flex;align-items:center;justify-content:space-between;gap:12px;flex-wrap:wrap;margin-bottom:16px}
.gbar-r{display:flex;gap:10px;align-items:center;margin-left:auto}
.pill{background:var(--card);border:1px solid var(--line);border-radius:10px;padding:7px 13px;font-size:13px;color:var(--mut);font-weight:600}
.pill b{color:var(--tx);font-family:var(--mono);margin-left:5px;font-size:15px}
.board{display:flex;justify-content:center;align-items:center;min-height:200px;margin:0 auto}
.how{max-width:680px;margin:22px auto 0;color:var(--tx2);font-size:13.5px;background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:14px 16px;line-height:1.6}
.how b{color:var(--tx)}

/* 2048 */
.b2048{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;width:min(420px,92vw);aspect-ratio:1;background:var(--bg2);border:1px solid var(--line2);border-radius:var(--r2);padding:10px}
.b2048 .t{display:grid;place-items:center;border-radius:10px;background:var(--card3);font-weight:800;font-size:clamp(18px,5vw,30px);font-family:var(--mono);color:var(--tx);transition:.1s}
.b2048 .t2{background:#39415c}.b2048 .t4{background:#454d6e}
.b2048 .t8{background:#5b8cff;color:#fff}.b2048 .t16{background:#4f7ef0;color:#fff}
.b2048 .t32{background:#7c6cf0;color:#fff}.b2048 .t64{background:#8b5cf6;color:#fff}
.b2048 .t128{background:#a855f7;color:#fff;font-size:clamp(16px,4.4vw,26px)}
.b2048 .t256{background:#c026d3;color:#fff;font-size:clamp(16px,4.4vw,26px)}
.b2048 .t512{background:#e0218a;color:#fff;font-size:clamp(16px,4.4vw,26px)}
.b2048 .t1024{background:#f0a020;color:#fff;font-size:clamp(14px,3.6vw,22px)}
.b2048 .t2048{background:#ffb020;color:#23150a;font-size:clamp(14px,3.6vw,22px);box-shadow:0 0 24px -2px #ffb020}

/* Word guess */
.bword{flex-direction:column;gap:6px}
.wrow{display:flex;gap:6px;justify-content:center}
.wc{width:54px;height:54px;display:grid;place-items:center;border:2px solid var(--line2);border-radius:8px;font-weight:800;font-size:24px;text-transform:uppercase;color:var(--tx);background:var(--card)}
.wc.correct{background:#2dd4a7;border-color:#2dd4a7;color:#06231b}
.wc.present{background:#ffb020;border-color:#ffb020;color:#241803}
.wc.absent{background:var(--card3);border-color:var(--card3);color:var(--mut)}
.wc.shake{animation:shake .3s}
@keyframes shake{0%,100%{transform:translateX(0)}25%{transform:translateX(-5px)}75%{transform:translateX(5px)}}
.krow{display:flex;gap:5px;justify-content:center;margin-top:6px}
.key{min-width:30px;height:46px;padding:0 9px;border:0;border-radius:7px;background:var(--card3);color:var(--tx);font-weight:700;font-size:14px;cursor:pointer;font-family:inherit}
.key.wide{min-width:46px;font-size:16px}
.key:hover{filter:brightness(1.15)}
.key.correct{background:#2dd4a7;color:#06231b}.key.present{background:#ffb020;color:#241803}.key.absent{background:#2a3043;color:var(--mut)}
@media(max-width:480px){.wc{width:46px;height:46px;font-size:20px}.key{min-width:26px;height:42px;padding:0 6px}}

/* Minesweeper */
.bmine{display:grid;grid-template-columns:repeat(var(--n),1fr);gap:3px;width:min(420px,92vw);aspect-ratio:1;background:var(--card2);border:1px solid var(--line2);border-radius:var(--r2);padding:8px}
.mc{display:grid;place-items:center;border-radius:5px;background:var(--card3);cursor:pointer;font-weight:800;font-size:clamp(12px,3vw,17px);font-family:var(--mono);user-select:none;transition:.05s}
.mc:hover{filter:brightness(1.2)}
.mc.open{background:var(--card);cursor:default;box-shadow:inset 0 0 0 1px var(--line)}
.mc.boom{background:var(--live)}
.mc[data-n="1"]{color:#5b8cff}.mc[data-n="2"]{color:#2dd4a7}.mc[data-n="3"]{color:#ff4d6a}.mc[data-n="4"]{color:#a855f7}
.mc[data-n="5"]{color:#ffb020}.mc[data-n="6"]{color:#22d3ee}.mc[data-n="7"]{color:#f472b6}.mc[data-n="8"]{color:#94a3b8}

/* Snake */
.bsnake canvas{background:var(--card2);border:1px solid var(--line2);border-radius:var(--r2);max-width:92vw;height:auto;touch-action:none}

/* Memory */
.bmem{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;width:min(420px,92vw)}
.mcard{aspect-ratio:1;border:1px solid var(--line2);border-radius:12px;background:var(--card3);cursor:pointer;font-size:clamp(22px,7vw,34px);display:grid;place-items:center;transition:.12s}
.mcard:hover{border-color:var(--acc)}
.mcard.up{background:var(--card);border-color:var(--acc);box-shadow:var(--sh)}
.mcard span{pointer-events:none}

/* Typing test */
.btype{flex-direction:column;align-items:stretch;width:min(720px,94vw);gap:14px}
.tt-text{background:var(--card);border:1px solid var(--line);border-radius:var(--r2);padding:18px 20px;font-size:20px;line-height:1.9;font-family:var(--mono);letter-spacing:.3px;color:var(--mut)}
.tt-text span{transition:.05s}
.tt-text span.ok{color:var(--ok)}
.tt-text span.bad{color:#fff;background:var(--live);border-radius:3px}
.tt-text span.cur{background:color-mix(in srgb,var(--acc) 35%,transparent);border-radius:3px}
.tt-in{width:100%;min-height:90px;background:var(--card2);border:1px solid var(--line2);border-radius:var(--r);color:var(--tx);font-size:16px;font-family:var(--mono);padding:12px 14px;resize:vertical}
.tt-in:focus{outline:0;border-color:var(--acc)}

/* game-over / hint overlay (replaces blocking alert) */
.gover{position:absolute;inset:0;display:grid;place-items:center;background:color-mix(in srgb,var(--bg) 70%,transparent);backdrop-filter:blur(3px);border-radius:var(--r2);z-index:5;padding:16px;text-align:center;animation:fade .18s ease}
@keyframes fade{from{opacity:0}to{opacity:1}}
.gover-in{display:flex;flex-direction:column;gap:16px;align-items:center}
.gover-m{font-size:clamp(18px,4vw,22px);font-weight:820;color:var(--tx);text-shadow:0 2px 8px rgba(0,0,0,.4)}

/* status page */
.srow{display:flex;justify-content:space-between;align-items:center;padding:13px 16px;border-bottom:1px solid var(--line);font-size:14px;background:var(--card)}
.srow:first-child{border-radius:var(--r2) var(--r2) 0 0}
.srow:last-child{border-bottom:0;border-radius:0 0 var(--r2) var(--r2)}
.srow .ok{color:var(--ok);font-weight:600;font-size:13px}

/* 404 */
.e404{min-height:calc(100vh - 64px);display:grid;place-items:center;text-align:center;padding:40px 20px}
.e404 .big{font-size:clamp(80px,18vw,150px);font-weight:850;background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent;line-height:1}

/* footer */
footer{border-top:1px solid var(--line);margin-top:60px;padding:40px 0 30px;color:var(--mut);font-size:13px;background:var(--bg2)}
.foot-top{display:grid;grid-template-columns:1.6fr 1fr 1fr 1fr;gap:24px;padding-bottom:26px;border-bottom:1px solid var(--line)}
.foot-col{display:flex;flex-direction:column;gap:9px}
.foot-col b{color:var(--tx);font-size:13px;margin-bottom:2px}
.foot-col a:hover{color:var(--tx)}
.foot-bot{padding-top:20px;display:flex;justify-content:space-between;flex-wrap:wrap;gap:10px}
@media(max-width:680px){.foot-top{grid-template-columns:1fr 1fr}}