:root{font-family:system-ui,-apple-system,Segoe UI,sans-serif;color:#183047;background:#f5f8fb}*{box-sizing:border-box}body{margin:0}a{color:#145c95}button{font:inherit;cursor:pointer;border:0;border-radius:12px;background:#145c95;color:#fff;padding:13px 18px;font-weight:700}button:hover{filter:brightness(.94)}button:focus-visible,a:focus-visible{outline:3px solid #e5a331;outline-offset:3px}button:disabled{opacity:.75;cursor:default}.wrap{max-width:1080px;margin:auto;padding:20px}.top{background:white;border-bottom:1px solid #dae4ee}.head{display:flex;align-items:center;justify-content:space-between;gap:16px}.brand{font-size:1.35rem;font-weight:850;text-decoration:none;color:#183047}.nav{display:flex;flex-wrap:wrap;gap:8px}.nav a{padding:9px 11px;border-radius:9px;text-decoration:none;color:#183047;font-weight:650}.nav a[aria-current=page],.nav a:hover{background:#e5f2fc}.menu{display:none}.hero{background:#183047;color:#fff;padding:35px;border-radius:22px}.hero h1{font-size:clamp(2rem,5vw,3.4rem);margin:0 0 12px}.hero p{max-width:680px;line-height:1.65}.hero a{color:#fff}.grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:15px}.tile,.panel{background:white;border:1px solid #dce5ee;border-radius:18px;padding:22px}.tile{display:flex;flex-direction:column}.tile p{flex:1}.tile a{display:inline-block;background:#145c95;color:white;border-radius:10px;padding:11px 14px;text-decoration:none;font-weight:700;text-align:center}.muted{color:#52677b}.small{font-size:.87rem}.panel{margin:20px 0;line-height:1.65}.panel h2:first-child{margin-top:0}.ad{border:1px dashed #b4c4d4;border-radius:12px;padding:17px;text-align:center;color:#52677b;margin:22px 0;font-size:.8rem}.hidden{display:none!important}.answer{display:block;width:100%;text-align:left;background:#eef4fa;color:#183047;border:1px solid #ccdce9;margin:10px 0}.answer.correct{background:#d9f4e4;border-color:#167446}.answer.wrong{background:#ffe4e1;border-color:#a93737}.progress{height:9px;background:#e5ecf3;border-radius:8px;overflow:hidden}.progress>div{height:100%;background:#145c95}.game{max-width:760px;margin:20px auto}.feedback{min-height:48px}.memory-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:9px}.memory-grid button{min-height:90px;font-size:1.5rem;background:#145c95}.memory-grid button.revealed,.memory-grid button.matched{background:#e6f4f0;color:#183047}.memory-grid button.matched{border:2px solid #20835e}.status{min-height:28px}.footer{border-top:1px solid #dce5ee;margin-top:40px;font-size:.9rem;line-height:1.7}.footer a{margin-right:12px}.tag{display:inline-block;border-radius:30px;padding:6px 12px;background:#dcecf7;color:#183047;font-size:.85rem}input{font:inherit;padding:12px;border:1px solid #a9bfd1;border-radius:9px;max-width:100%}@media(max-width:750px){.head{flex-wrap:wrap}.menu{display:block}.nav{display:none;width:100%;flex-direction:column}.nav.open{display:flex}.hero{padding:24px}.wrap{padding:15px}.memory-grid button{min-height:65px}}

:root{--accent:#087e83}body{background:linear-gradient(180deg,#f0f8f8 0,#f8fafc 450px)}.hero{background:linear-gradient(120deg,#123f52,#126c73)}.tile{border-top:4px solid #0e9291;box-shadow:0 5px 20px #16364c0a}.tile:nth-child(3n+2){border-top-color:#d48a32}.tile:nth-child(3n){border-top-color:#7773bb}.tile a,button{background:#126c73}.answer{background:#edf6f5;color:#163047}.word-display{font-size:clamp(1.2rem,3vw,1.8rem);font-weight:750;letter-spacing:.025em;background:#eef7f7;padding:22px;border-radius:12px;min-height:85px}.number-buttons{display:grid;grid-template-columns:repeat(3,1fr);gap:10px}.number-buttons .answer{text-align:center;font-size:1.5rem;min-height:75px;margin:0}.number-buttons .answer:disabled{background:#d6eee1;color:#254b3c}.panel{box-shadow:0 4px 15px #16364c07}@media(prefers-reduced-motion:no-preference){button,.tile{transition:transform .12s ease}button:not(:disabled):active{transform:scale(.98)}}

/* v10: more personality without sacrificing readability */
:root{--ink:#20334b;--teal:#087e83;--violet:#6c54bc;--sun:#ffbe63;--pink:#f49bb4}
body{color:var(--ink);background:radial-gradient(ellipse at 12% 3%,#d8f4f2 0,transparent 36%),radial-gradient(ellipse at 91% 18%,#f2e6ff 0,transparent 33%),linear-gradient(180deg,#fffaf2 0%,#f6fbff 54%,#f9f6ff 100%)}
.top{background:#ffffffed;box-shadow:0 4px 22px #20334b0a;position:relative;z-index:2}
.brand{font-weight:900;letter-spacing:-.035em;color:#174b5b}.brand::first-letter{color:#a85cc8}
.nav a{transition:background .15s,color .15s}.nav a:hover,.nav a[aria-current=page]{background:#e4f5f1;color:#075d62}
.hero{position:relative;overflow:hidden;background:linear-gradient(118deg,#153a63 0%,#135e76 49%,#5c4d9b 100%);box-shadow:0 16px 36px #1a466028;border:1px solid #ffffff30}
.hero::after{content:'✦  ◇  ✧';position:absolute;right:4%;top:8%;font-size:clamp(2rem,6vw,5rem);letter-spacing:.35em;color:#ffffff24;pointer-events:none;transform:rotate(-13deg)}
.hero h1,.hero p,.hero .tag,.hero a{position:relative;z-index:1}.hero h1{letter-spacing:-.045em;max-width:790px}.hero .tag{background:#ffffff24;color:#fff;border:1px solid #ffffff55}
.tile,.panel{box-shadow:0 9px 28px #27394f0c;border:1px solid #e0e6f0}.tile{border-top:5px solid #00a5a1;transition:transform .18s,box-shadow .18s}.tile:nth-child(4n+2){border-top-color:#ffb44d}.tile:nth-child(4n+3){border-top-color:#9876d7}.tile:nth-child(4n){border-top-color:#ef8ca7}
.tile:nth-child(4n+2) a{background:#8653a5}.tile:nth-child(4n+3) a{background:#a64f75}.tile:nth-child(4n) a{background:#176a9c}
.tile a,button{min-height:44px;background:#087e83}.tile a:hover,button:hover{filter:brightness(1.08)}
.answer{border:2px solid #d5e5ef;background:#f4faff;min-height:50px}.answer:hover:not(:disabled){background:#e5f4fb;border-color:#60b3c6}.answer.correct{background:#d9f4e4;border-color:#167446}.answer.wrong{background:#ffe4e1;border-color:#a93737}
.game{border-top:5px solid #9473d3}.progress>div{background:linear-gradient(90deg,#11a7a1,#9670d2)}
@media(min-width:751px){.tile:hover{transform:translateY(-3px);box-shadow:0 16px 35px #27394f17}}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{transition:none!important;animation:none!important}}

/* v16: illustrated identity, more vivid but accessible and motion-sensitive */
:root{--ink:#193449;--sea:#087e83;--purple:#7153b7;--peach:#f9b76e;--berry:#b34c79}
body{background:radial-gradient(circle at 5% 2%,#d5f5f1 0,transparent 28%),radial-gradient(circle at 98% 13%,#f1dffd 0,transparent 30%),linear-gradient(160deg,#fffaf2,#f4fbff 52%,#faf5ff)}
.top{border-bottom:3px solid transparent;border-image:linear-gradient(90deg,#18a9a2,#9c70db,#f6a15e) 1}
.brand{font-size:1.42rem}.hero-feature{display:flex;align-items:center;justify-content:space-between;gap:16px;min-height:290px;background:linear-gradient(115deg,#123b60,#096b78 52%,#624c9f)}
.hero-feature .hero-copy{position:relative;z-index:1;max-width:650px}.hero-feature .brain-art{flex:0 0 min(32%,250px);width:min(32%,250px);height:auto;filter:drop-shadow(0 12px 22px #0a203a44)}
.hero-feature::after{display:none}.hero-feature h1{font-size:clamp(2.2rem,5.5vw,4rem);line-height:1.06}.hero-feature p{font-size:1.07rem}.hero-feature button{background:#ffe0a6;color:#20334b;box-shadow:0 5px 0 #d2a76a;font-weight:850}
.hero-feature button:hover{background:#fff0cc;filter:none}.tile{position:relative;overflow:hidden}.tile::before{content:'';position:absolute;right:-25px;top:-35px;width:100px;height:100px;border-radius:50%;background:#a9e6df44;pointer-events:none}.tile:nth-child(4n+2)::before{background:#ffcd8d55}.tile:nth-child(4n+3)::before{background:#c9b5f455}.tile:nth-child(4n)::before{background:#f4b7d155}
.home-prompt{background:linear-gradient(110deg,#e5faf5,#f3eaff);border:2px solid #c9e8e8}.pill-link{display:inline-block;margin:6px 6px 6px 0;padding:11px 16px;border-radius:999px;background:#087e83;color:white!important;font-weight:750;text-decoration:none}.pill-alt{background:#7153b7}.next-challenge{margin-top:20px;padding:18px;background:linear-gradient(115deg,#e5faf5,#f5eaff);border-radius:16px}.next-challenge h3{margin-top:0}.game .tag{background:#e8dfff;color:#4c3685;font-weight:750}.game .progress{height:12px}.game .answer{border-radius:13px}.game .answer:focus-visible{outline:3px solid #e5a331;outline-offset:2px}
@media(max-width:650px){.hero-feature{min-height:0;align-items:flex-start}.hero-feature .brain-art{flex:0 0 96px;width:96px;margin:-4px -16px 0 -45px;opacity:.6}.hero-feature .hero-copy{z-index:1}.hero-feature h1{font-size:clamp(2rem,8vw,3rem)}.hero-feature p{font-size:1rem}}
@media(prefers-reduced-motion:no-preference){.hero-feature .brain-art{animation:floatBrain 5s ease-in-out infinite}.tile:hover{transform:translateY(-4px)}.progress>div{transition:width .3s ease}@keyframes floatBrain{0%,100%{transform:translateY(0) rotate(-2deg)}50%{transform:translateY(-8px) rotate(2deg)}}}

/* Optional shared leaderboard */
.leaderboard{margin-block:1.3rem}.board-form-row{display:flex;gap:.6rem;flex-wrap:wrap;align-items:center;margin-top:.5rem}.board-form-row input{max-width:10rem;padding:.8rem;border:2px solid #527f92;border-radius:12px;font:inherit;text-transform:uppercase;background:white;color:#183047}.board-tabs{display:flex;gap:.5rem;flex-wrap:wrap}.board-tabs button{background:#e6f5f3;color:#17384b;border:2px solid #b5ded9}.board-tabs button[aria-pressed="true"]{background:#155f70;color:white;border-color:#155f70}.board-list{padding-left:1.5rem}.board-list li{padding:.55rem;border-bottom:1px solid #d7e7e8}.board-list li span{float:right;font-weight:700}.board-list li::marker{font-weight:700}@media(max-width:420px){.board-tabs button{font-size:.84rem;padding:.65rem}.board-form-row input{width:100%}}