:root{--purple:#6555e8;--ink:#24304a;--muted:#65708a;--line:#e5e8f5;--cream:#fbfaff}*{box-sizing:border-box}body{margin:0;color:var(--ink);background:linear-gradient(180deg,#faf7ff,#f2f9ff 58%,#fffaf2);font-family:'Hind Siliguri','Noto Sans Bengali','Nirmala UI',system-ui,sans-serif}button,select{font:inherit}button{cursor:pointer}button:focus-visible,select:focus-visible{outline:3px solid #ffb93b;outline-offset:3px}.top{display:flex;align-items:center;justify-content:space-between;gap:14px;max-width:1200px;margin:auto;padding:18px 20px}.brand{display:flex;gap:9px;align-items:center;text-decoration:none;color:var(--ink);font-weight:900;font-size:22px;white-space:nowrap}.brand em{font-style:normal;color:var(--purple)}.logo{display:grid;place-items:center;background:#7257ec;color:white;width:38px;height:38px;border-radius:12px}.top nav{display:flex;gap:8px}.navbtn,.language{background:white;border:1px solid var(--line);border-radius:15px;padding:10px 14px;color:#35405c;font-weight:700}.language{background:#efeaff;color:#5141bf}main{max-width:1120px;margin:auto;padding:8px 20px 60px}.page{animation:appear .2s ease}.hidden{display:none!important}@keyframes appear{from{opacity:.3;transform:translateY(7px)}to{opacity:1;transform:none}}.hero{display:grid;grid-template-columns:1.1fr .9fr;gap:24px;align-items:center;min-height:390px;background:linear-gradient(125deg,#eee7ff,#e6f8ff 65%,#fff0ce);padding:44px;border-radius:32px;overflow:hidden}.pill{background:#fff;border-radius:30px;padding:8px 15px;color:#6049d1;font-size:14px;font-weight:800;display:inline-block}.hero h1{font-size:clamp(32px,4.4vw,56px);line-height:1.24;margin:22px 0 12px;color:#332e6c}.hero p{font-size:17px;line-height:1.7;max-width:520px}.heroactions{display:flex;gap:12px;flex-wrap:wrap;margin:22px 0}.primary,.secondary{border:0;border-radius:15px;padding:14px 23px;font-weight:800;box-shadow:0 5px 0 #d4cdef}.primary{background:#6752e8;color:white;box-shadow:0 5px 0 #4a39b9}.secondary{background:white;color:#5544c0;border:1px solid #e0dafa}.primary:active,.secondary:active{transform:translateY(3px);box-shadow:none}.subtle{font-size:13px!important;color:var(--muted)}.heroart{height:330px;position:relative;display:grid;place-items:center}.bigcard{background:white;border-radius:30px;box-shadow:0 20px 45px #6a55ba26;transform:rotate(-7deg);padding:36px;font-size:56px;font-weight:900;color:#5944d4}.bigcard span{color:#ff8c56}.bigcard strong{color:#14ad8e}.mascot{position:absolute;font-size:92px;bottom:-12px;right:4%;transform:rotate(12deg)}.planet{position:absolute;font-size:60px;top:0;right:12%}.stars{position:absolute;font-size:32px;bottom:25px;left:0}.sectiontitle{font-size:29px;margin:36px 0 18px}.worlds{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}.world{border:0;text-align:left;display:flex;flex-direction:column;gap:12px;padding:25px;border-radius:25px;min-height:208px;transition:transform .15s}.world:hover{transform:translateY(-4px)}.world span{font-size:53px}.world strong{font-size:22px}.world small{font-size:14px;color:#48526b}.worldmath{background:#ffebd5}.worldbangla{background:#e3f5e7}.worldchallenge{background:#e8e8ff}.notice{background:#fff;border:1px solid var(--line);border-radius:18px;padding:18px;margin-top:26px;display:flex;gap:12px;flex-wrap:wrap}.notice span{color:var(--muted)}.sectionhead{text-align:center;margin:20px 0 26px}.sectionhead h2{font-size:34px;margin:14px 0 4px}.sectionhead p{color:var(--muted)}.back{border:0;background:#fff;border-radius:12px;padding:9px 15px;color:#5949c5;font-weight:700}.setup{background:white;border:1px solid var(--line);border-radius:22px;padding:20px;display:grid;grid-template-columns:repeat(3,1fr) auto;align-items:end;gap:14px}.setup label{display:grid;gap:7px;font-weight:700}.setup select{border:1px solid #d9dcef;border-radius:12px;padding:12px;background:#fbfbff;min-width:0;width:100%}.topicgrid{display:grid;grid-template-columns:repeat(4,1fr);gap:14px;margin-top:20px}.topiccard{border:1px solid #e6e3f5;background:white;border-radius:19px;padding:18px;min-height:112px;text-align:center;font-weight:800;color:#37405c}.topiccard span{display:block;font-size:32px;margin-bottom:6px}.topiccard:hover{border-color:#8776ed;background:#f8f5ff}.playtop{display:flex;justify-content:space-between;align-items:center;gap:12px}.score{font-size:20px;font-weight:900;color:#d78a08}.progressbar{height:12px;border-radius:20px;background:#e7e5f5;overflow:hidden;margin:18px 0}.progressbar div{height:100%;background:linear-gradient(90deg,#6b59eb,#19bca3);width:0;transition:width .3s}.questionbox{max-width:780px;margin:20px auto;background:white;border:1px solid var(--line);border-radius:28px;box-shadow:0 18px 40px #4444770c;padding:30px;text-align:center}.questionbox h2{font-size:clamp(25px,4vw,42px);margin:15px 0}.level{color:#6753d9;font-weight:800}.visual{font-size:36px;line-height:1.7;max-width:580px;margin:16px auto;word-break:break-word}.visual .item{display:inline-block;margin:3px}.choices{display:grid;grid-template-columns:repeat(2,1fr);gap:13px;margin:20px auto;max-width:560px}.choice{background:#f5f3ff;border:2px solid #e4ddff;border-radius:18px;min-height:68px;padding:12px;font-size:23px;font-weight:800;color:#38306f}.choice:hover:not(:disabled){background:#e9e2ff}.choice.correct{background:#d5fae9;border-color:#29b881}.choice.wrong{background:#ffe0df;border-color:#e97b75}.feedback{min-height:30px;font-size:20px;font-weight:800;margin:12px 0}.feedback.good{color:#12946a}.feedback.bad{color:#d05255}.explain{color:#52617c;margin:10px auto 18px;line-height:1.7;max-width:550px}.resultcard{text-align:center;background:white;border-radius:28px;max-width:620px;margin:50px auto;padding:48px 24px;border:1px solid var(--line)}.trophy{font-size:88px}.resultscore{font-size:46px;font-weight:900;color:#6653dd}.resultcard button{margin:8px}.tabs{display:flex;gap:10px;flex-wrap:wrap;justify-content:center;margin-bottom:24px}.tabs button{background:white;border:2px solid #e2e1f4;border-radius:20px;padding:12px 18px;font-weight:800}.tabs button.active{background:#6555e8;color:white;border-color:#6555e8}.lettergrid{display:grid;grid-template-columns:repeat(8,1fr);gap:12px}.letter{border:1px solid #e5e3f4;border-radius:17px;background:white;padding:15px 4px;min-height:84px;font-size:34px;font-weight:800;color:#5c4ad1}.letter:hover{background:#fff0d8}.letterdetail{max-width:500px;margin:25px auto;text-align:center;background:white;border-radius:24px;padding:25px;border:1px solid var(--line)}.bigletter{font-size:110px;font-weight:900;color:#6655df}.letterword{font-size:24px}.letteractions{display:flex;gap:12px;justify-content:center;margin-top:20px}.bqprompt{font-size:29px;font-weight:800}footer{text-align:center;padding:28px;color:#75809b;border-top:1px solid #eae8f4}@media(max-width:850px){.top{flex-wrap:wrap}.top nav{order:3;width:100%;justify-content:center}.hero{grid-template-columns:1fr;padding:30px}.heroart{height:230px}.bigcard{font-size:43px;padding:26px}.mascot{font-size:65px}.setup{grid-template-columns:repeat(2,1fr)}.topicgrid{grid-template-columns:repeat(3,1fr)}.lettergrid{grid-template-columns:repeat(6,1fr)}}@media(max-width:560px){.top{padding:12px}.brand{font-size:18px}.navbtn,.language{padding:8px 10px;font-size:13px}main{padding:8px 12px 45px}.hero{padding:25px 20px;border-radius:22px}.hero h1{font-size:32px}.heroart{height:175px}.bigcard{font-size:34px;padding:20px}.planet{font-size:37px}.mascot{font-size:56px}.worlds{grid-template-columns:1fr}.world{min-height:115px;padding:18px;gap:6px}.world span{font-size:36px}.setup{grid-template-columns:1fr}.topicgrid{grid-template-columns:repeat(2,1fr)}.questionbox{padding:18px 12px}.choice{font-size:20px;min-height:64px}.lettergrid{grid-template-columns:repeat(4,1fr);gap:8px}.letter{font-size:29px;min-height:70px}.sectionhead h2{font-size:28px}}

/* V4: unified Bengali/Latin typography and colorful accessible UI */
html,body,button,select,input,textarea{font-family:'Hind Siliguri','Nirmala UI',sans-serif!important}
body{background:radial-gradient(circle at 8% 8%,#ffe7f1 0,transparent 24%),radial-gradient(circle at 90% 18%,#ddfaff 0,transparent 28%),linear-gradient(180deg,#fff9e9,#f7f0ff 48%,#edfff5);min-height:100vh}
.top{background:#ffffffd9;backdrop-filter:blur(14px);border-radius:0 0 24px 24px;box-shadow:0 6px 24px #524a9820;margin-bottom:12px}
.logo{background:linear-gradient(135deg,#ff6b9b,#8257ee,#30c6cc);box-shadow:0 5px 15px #a071e95c}
.language{background:linear-gradient(120deg,#ffec88,#ffd5e6);border:2px solid #fff;color:#59368d;box-shadow:0 4px 12px #b679d230}
.hero{background:linear-gradient(120deg,#f7dcff 0%,#d9f9ff 43%,#fff0ad 100%);box-shadow:0 20px 50px #7e6acf20;border:2px solid #ffffffb8;position:relative}
.hero:before{content:'✦ ✨ ✦';position:absolute;top:15px;right:24px;color:#ec8ec0;letter-spacing:14px}
.hero h1{background:linear-gradient(100deg,#7b40d2,#ed5790,#df8d15);background-clip:text;-webkit-background-clip:text;color:transparent;font-weight:800}
.primary{background:linear-gradient(115deg,#6c55ef,#9a52e9);box-shadow:0 5px 0 #5542b8}
.primary:hover{filter:brightness(1.07)}
.world{border:2px solid #ffffffdb;box-shadow:0 12px 26px #6a6ab020;position:relative;overflow:hidden}
.world:after{content:'✦';position:absolute;right:16px;top:10px;font-size:32px;color:#ffffffb8}
.worldmath{background:linear-gradient(135deg,#ffedba,#ffd3dc)}
.worldbangla{background:linear-gradient(135deg,#c9f8e5,#d4eaff)}
.worldchallenge{background:linear-gradient(135deg,#e5d6ff,#ffcfea)}
.world:hover,.topiccard:hover,.letter:hover{transform:translateY(-4px);box-shadow:0 14px 28px #8173b02c}
.topiccard,.letter,.questionbox,.resultcard,.letterdetail,.setup{box-shadow:0 10px 25px #7777a017;border:2px solid #fff}
.topiccard:nth-child(5n+1){background:#fff1d9}.topiccard:nth-child(5n+2){background:#e4f7ff}.topiccard:nth-child(5n+3){background:#e8fbe7}.topiccard:nth-child(5n+4){background:#f4eaff}.topiccard:nth-child(5n){background:#ffe9f0}
.letter:nth-child(4n+1){background:#fff0d9}.letter:nth-child(4n+2){background:#e2f8fa}.letter:nth-child(4n+3){background:#e8fbe7}.letter:nth-child(4n){background:#f5e9ff}
.choice{transition:transform .15s,box-shadow .15s}.choice:hover:not(:disabled){transform:scale(1.03);box-shadow:0 8px 16px #8d72b92a}
.float-bubble{position:absolute;font-size:34px;filter:drop-shadow(0 5px 8px #8884);animation:bob 4s ease-in-out infinite}.b1{left:8%;top:12%}.b2{right:2%;top:32%;animation-delay:1s}.b3{left:15%;bottom:10%;animation-delay:2s}@keyframes bob{50%{transform:translateY(-12px) rotate(9deg)}}
@media(max-width:560px){.hero{padding:26px 18px}.hero h1{line-height:1.4}.float-bubble{font-size:23px}.top nav{flex-wrap:wrap}.world{min-height:125px}}
@media(prefers-reduced-motion:reduce){.float-bubble,.page{animation:none!important}.world,.topiccard,.letter,.choice{transition:none!important}}

/* V5 Deep Color Carnival — saturated, legible, child-friendly */
:root{--purple:#5922ca;--ink:#1e1747;--muted:#50466c;--line:#b7a5e9}
body{background:radial-gradient(circle at 4% 14%,#ffac31 0,transparent 22%),radial-gradient(circle at 95% 8%,#00b7df 0,transparent 27%),radial-gradient(circle at 85% 85%,#fd64a6 0,transparent 30%),linear-gradient(145deg,#6336dc 0%,#ab3cc4 40%,#ff8d3b 100%);color:var(--ink)}
.top{background:#351783f2;border:2px solid #a887ff;border-top:0;box-shadow:0 10px 30px #25105855}
.brand,.brand em{color:#fff}.brand em{color:#ffe44f}.logo{background:linear-gradient(135deg,#ffae13,#ff448a);box-shadow:0 5px 0 #b81f6d}
.navbtn{background:#7546df;color:#fff;border:2px solid #ac8dff}.navbtn:hover{background:#a45cff}
.language{background:#ffcf22;color:#37205f;border:2px solid #fff1a4;font-weight:900}
.hero{background:linear-gradient(115deg,#6532dc 0%,#ab31b6 48%,#f35784 100%);border:3px solid #ffd45e;box-shadow:0 16px 0 #3d188c88,0 28px 45px #240c6540}
.hero h1{background:none;color:#fff4a4;text-shadow:0 4px 0 #4e198d;font-weight:900}
.hero p{color:#fff; font-weight:600}.hero .subtle{color:#fff0d2}.pill{background:#ffe35d;color:#4b2079;box-shadow:0 5px 0 #d99518}
.primary{background:linear-gradient(135deg,#ffb71b,#ff6e2c);color:#2f1559;box-shadow:0 5px 0 #bd3c21;border:2px solid #ffe399}
.secondary{background:#fff;color:#4d20a2;border:2px solid #a98cf4;box-shadow:0 5px 0 #6b3ba4}
.bigcard{background:#fff7c9;border:5px solid #ffbb22;box-shadow:0 12px 0 #4b218a;color:#6425c9}.bigcard span{color:#e83c77}.bigcard strong{color:#087f76}
.sectiontitle{color:#fff8c3;text-shadow:0 3px 0 #5c1f88}.world{border:3px solid #fff7ce;box-shadow:0 9px 0 #3e20757d,0 18px 24px #27115b55}
.world strong{color:#fff;font-size:24px;text-shadow:0 2px 0 #37215c}.world small{color:#fff;font-weight:700}.worldmath{background:linear-gradient(140deg,#f66a16,#e93b75)}.worldbangla{background:linear-gradient(140deg,#04a67e,#0877c7)}.worldchallenge{background:linear-gradient(140deg,#7137d9,#c63aa6)}
.notice{background:#fff0b6;border:3px solid #ffb72d;box-shadow:0 6px 0 #a85d3d}.notice span{color:#4b3060}
.sectionhead h2{color:#fff5a5;text-shadow:0 3px 0 #51218e}.sectionhead p{color:#fff;font-weight:700}.back{background:#ffdd54;color:#4b2189;border:2px solid #fff3bd}
.setup{background:#401a96;border:3px solid #f5c85d;box-shadow:0 8px 0 #32116e}.setup label{color:#fff}.setup select{background:#fff5d1;border:2px solid #e7a735;color:#2d1755}
.topiccard{border:3px solid #fff1b8;color:#fff;box-shadow:0 6px 0 #3c217c70;text-shadow:0 1px 0 #30104d55}
.topiccard:nth-child(5n+1){background:#e94c50}.topiccard:nth-child(5n+2){background:#047cbe}.topiccard:nth-child(5n+3){background:#0a9b75}.topiccard:nth-child(5n+4){background:#7434d1}.topiccard:nth-child(5n){background:#c12e9e}
.playtop{color:#fff;font-weight:800}.score{background:#ffdb3e;color:#562277;padding:8px 14px;border-radius:15px}.progressbar{background:#462289;border:2px solid #ffc954}.progressbar div{background:linear-gradient(90deg,#ffdc28,#3df1b5)}
.questionbox,.resultcard,.letterdetail{background:#fff1c9;border:4px solid #ffcb45;box-shadow:0 10px 0 #4e238d88,0 20px 35px #2b115844}
.questionbox h2,.bqprompt{color:#41217b}.level{color:#7432bc}.choice{background:#fff;border:3px solid #a775e9;color:#3c2077;box-shadow:0 5px 0 #ac89cf}.choice:nth-child(4n+2){border-color:#f58c2f}.choice:nth-child(4n+3){border-color:#1aafaa}.choice:nth-child(4n+4){border-color:#e95791}.choice:hover:not(:disabled){background:#ffe27d}.choice.correct{background:#baf8d3;border-color:#0b9e68}.choice.wrong{background:#ffd0d0;border-color:#d83b4a}.explain{color:#4d3268}
.resultscore{color:#7428b8}.tabs button{background:#fff0be;border:2px solid #ffcc51;color:#51207f;box-shadow:0 4px 0 #592e8e}.tabs button.active{background:#4f1eaa;border-color:#ffdf6d;color:#fff}
.letter{border:3px solid #ffecaa;box-shadow:0 5px 0 #3e1d7c7a;color:#fff;text-shadow:0 2px 0 #4a1b7766}
.letter:nth-child(4n+1){background:#e44879}.letter:nth-child(4n+2){background:#068fbb}.letter:nth-child(4n+3){background:#0c9d72}.letter:nth-child(4n){background:#7836cf}
.letter:hover{background:#ffad2d}.bigletter{color:#6a2db5}.letterword{color:#41206e}
footer{color:#fff9d5;background:#351783c9;border-top:2px solid #f4c65d;font-weight:700}
@media(max-width:560px){.top{border-radius:0 0 18px 18px}.hero{border-radius:22px}.world{min-height:130px}.sectiontitle{font-size:25px}.topiccard{min-height:104px}.questionbox{padding:18px 12px}.choice{min-height:65px}}

/* Voice controls */
.voice-action{display:inline-flex;align-items:center;justify-content:center;margin:10px auto 18px;padding:11px 18px;border:2px solid #4521a6;border-radius:999px;background:#6738d5;color:white;font:700 1rem 'Hind Siliguri',sans-serif;cursor:pointer;box-shadow:0 5px 0 #341481}.voice-action:hover{background:#4820b6}.voice-action:focus-visible,#voiceToggle:focus-visible{outline:3px solid #ffcb2f;outline-offset:3px}@media(max-width:600px){#voiceToggle{font-size:.8rem;padding:8px 10px}.voice-action{width:100%}}

/* V9: balanced mint, sky, lilac and sunshine palette */
body{background:radial-gradient(circle at 0 0,#d8f5ee 0,transparent 30%),radial-gradient(circle at 100% 5%,#e8e3ff 0,transparent 30%),linear-gradient(160deg,#f6fbff,#fffaf0 55%,#f1fff8);color:#26344d}
.top{background:#fffdfaeF;border-bottom:1px solid #dce9ed;border-radius:0 0 22px 22px;box-shadow:0 8px 28px #345d7212}
.brand,.brand em{color:#29557c}.logo{background:linear-gradient(140deg,#0d9e9b,#5177df)}
.navbtn,.language{background:#edf7ff;color:#225a85;border:1px solid #c7e4f2}
.hero{background:linear-gradient(120deg,#d6f4f1 0%,#e5edff 50%,#fff1cf 100%);border:2px solid #fff;box-shadow:0 16px 38px #3c719a1c}
.hero h1{background:none;color:#244d77;text-shadow:none}.hero p,.hero .subtle{color:#3d5871}.pill{background:#fff;color:#246c84;box-shadow:0 4px 0 #b4e6dc}
.primary{background:#3777d4;box-shadow:0 5px 0 #23509b;color:#fff}.secondary{background:#fff;color:#2e6c9a;border:1px solid #c7dfea;box-shadow:0 4px 0 #cbdce9}
.sectiontitle,.sectionhead h2{color:#2b587c;text-shadow:none}.sectionhead p{color:#51667c}.back{background:#e6f4ff;color:#286c95;border:1px solid #c3dfed}
.world{border:2px solid #fff;box-shadow:0 8px 22px #42628b1e}.world strong{color:#263c58;text-shadow:none}.world small{color:#435b72}
.worldmath{background:linear-gradient(145deg,#ffdfb5,#ffd1c3)}.worldbangla{background:linear-gradient(145deg,#baf3dc,#c9f0ff)}.worldchallenge{background:linear-gradient(145deg,#e3d5ff,#d6e8ff)}
.notice{background:#fffdf0;border:1px solid #e7ddb2;box-shadow:none}.notice span{color:#566780}
.setup,.daily-panel{background:#fff;border:2px solid #d7e9f2;box-shadow:0 8px 25px #335f8914}.setup label{color:#38506b}.setup select{background:#f8fcff;border:1px solid #d1e3ef;color:#2e4665}
.topiccard{border:2px solid #fff;color:#27445b;text-shadow:none;box-shadow:0 5px 16px #31557917}
.topiccard:nth-child(5n+1){background:#ffe0d2}.topiccard:nth-child(5n+2){background:#cbe9ff}.topiccard:nth-child(5n+3){background:#c9f3de}.topiccard:nth-child(5n+4){background:#e7dcff}.topiccard:nth-child(5n){background:#fff0b8}
.playtop{color:#2b4b6b}.score{background:#fff1bc;color:#77571e}.progressbar{background:#dbeaf4;border:0}.progressbar div{background:linear-gradient(90deg,#42a9dc,#37bca0)}
.questionbox,.resultcard,.letterdetail{background:#fff;border:2px solid #d9e7f1;box-shadow:0 10px 30px #305e8818}.questionbox h2,.bqprompt{color:#2c5276}.level,.resultscore{color:#4271b9}.choice{background:#f7fbff;border:2px solid #b9d8f1;color:#2c5276;box-shadow:0 3px 0 #d6e7f4}.choice:nth-child(4n+2){border-color:#eec98a}.choice:nth-child(4n+3){border-color:#a5dfcb}.choice:nth-child(4n+4){border-color:#d2c2f2}.choice:hover:not(:disabled){background:#e7f6ff}.choice.correct{background:#d2f8e3;border-color:#2aaf77}.choice.wrong{background:#ffe3e0;border-color:#d66d6a}
.tabs button{background:#fff;border:1px solid #cee1ed;color:#3a6385;box-shadow:none}.tabs button.active{background:#3a82bb;border-color:#3a82bb;color:#fff}
.letter{border:2px solid #fff;color:#2b4c6d;text-shadow:none;box-shadow:0 4px 12px #46698719}.letter:nth-child(4n+1){background:#ffe2d3}.letter:nth-child(4n+2){background:#c9e9ff}.letter:nth-child(4n+3){background:#caf3df}.letter:nth-child(4n){background:#e7dfff}.letter:hover{background:#fff0b7}.bigletter{color:#377db6}.letterword{color:#37536c}
.voice-action{background:#3685b9;border-color:#2c74a4;box-shadow:0 4px 0 #20587f}.voice-action:hover{background:#276c9b}
footer{background:transparent;border-top:1px solid #d8e8ef;color:#59728b}
.daily-panel{max-width:540px;margin:25px auto;border-radius:24px;padding:30px;display:grid;gap:18px;text-align:center}.daily-panel label{font-weight:800;color:#2c5276}.daily-panel select{width:100%;padding:12px;border-radius:12px;border:1px solid #b9d6e8;background:#f6fbff}.daily-best{padding:13px;border-radius:14px;background:#fff3d3;color:#685320;font-weight:700}