:root{--b50:#f0f9ff;--b100:#e0f2fe;--b200:#bae6fd;--b300:#7dd3fc;--b400:#38bdf8;--b500:#0ea5e9;--b600:#0284c7;--b700:#0369a1;--b900:#0c4a6e;--o500:#ea6c00;--o100:#ffedd5;--ink:#0f172a;--mut:#64748b;--line:#dbeafe;--ok:#059669;--okbg:#d1fae5;--bad:#dc2626;--badbg:#fee2e2;--warn:#b45309;--warnbg:#fef3c7;--card:#fff;--bg:#f4faff;--r:16px}
*{box-sizing:border-box}html{-webkit-text-size-adjust:100%}
body{margin:0;font-family:Inter,system-ui,-apple-system,"Segoe UI",Roboto,"Hiragino Sans","Noto Sans JP","Noto Sans",sans-serif;background:var(--bg);color:var(--ink);line-height:1.55;font-size:15px}
a{color:var(--b700);text-decoration:none}a:hover{text-decoration:underline}
h1,h2,h3{line-height:1.25;margin:0 0 .5em;color:var(--b900)}h1{font-size:1.7rem}h2{font-size:1.3rem}h3{font-size:1.05rem}
p{margin:0 0 .8em}img{max-width:100%}
.jp{font-family:"Hiragino Sans","Noto Sans JP","Yu Gothic","Meiryo",sans-serif}.emoji{font-family:"Apple Color Emoji","Segoe UI Emoji","Noto Color Emoji",sans-serif}
.wrap{max-width:1120px;margin:0 auto;padding:0 16px}
.muted{color:var(--mut)}.small{font-size:.85rem}.center{text-align:center}.right{text-align:right}.bold{font-weight:700}.hide{display:none!important}
.row{display:flex;gap:12px;align-items:center;flex-wrap:wrap}.between{justify-content:space-between}.col{display:flex;flex-direction:column;gap:12px}.grow{flex:1}.gap8{gap:8px}.mt{margin-top:16px}.mb{margin-bottom:16px}
.grid{display:grid;gap:14px}.g2{grid-template-columns:repeat(auto-fit,minmax(260px,1fr))}.g3{grid-template-columns:repeat(auto-fit,minmax(220px,1fr))}.g4{grid-template-columns:repeat(auto-fit,minmax(170px,1fr))}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:16px;box-shadow:0 1px 2px rgba(12,74,110,.04)}
.card.pad0{padding:0;overflow:hidden}.card.hl{background:linear-gradient(135deg,var(--b50),#fff);border-color:var(--b200)}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;border:1px solid var(--b200);background:#fff;color:var(--b700);padding:9px 16px;border-radius:12px;font:inherit;font-weight:600;cursor:pointer;min-height:40px;text-decoration:none!important}
.btn:hover{background:var(--b50)}.btn:disabled{opacity:.5;cursor:not-allowed}
.btn.p{background:var(--b600);border-color:var(--b600);color:#fff}.btn.p:hover{background:var(--b700)}
.btn.o{background:var(--o500);border-color:var(--o500);color:#fff}.btn.d{background:#fff;border-color:#fecaca;color:var(--bad)}.btn.d:hover{background:var(--badbg)}
.btn.s{padding:5px 11px;min-height:32px;font-size:.85rem;border-radius:10px}.btn.g{border-color:transparent;background:transparent}.btn.lg{padding:13px 24px;font-size:1.05rem;border-radius:14px}
.input,select,textarea{width:100%;border:1px solid #bfdbfe;border-radius:12px;padding:9px 12px;font:inherit;background:#fff;color:var(--ink);min-height:40px}
textarea{min-height:90px;resize:vertical}.input:focus,select:focus,textarea:focus{outline:3px solid var(--b200);border-color:var(--b400)}
label.f{display:block;font-weight:600;font-size:.85rem;margin-bottom:4px;color:var(--b900)}.fld{margin-bottom:12px}.hint{font-size:.8rem;color:var(--mut);margin-top:3px}
.badge{display:inline-flex;align-items:center;gap:4px;padding:2px 10px;border-radius:999px;font-size:.75rem;font-weight:700;background:var(--b100);color:var(--b700)}
.badge.ok{background:var(--okbg);color:var(--ok)}.badge.bad{background:var(--badbg);color:var(--bad)}.badge.warn{background:var(--warnbg);color:var(--warn)}.badge.o{background:var(--o100);color:var(--o500)}
.alert{padding:10px 14px;border-radius:12px;background:var(--b50);border:1px solid var(--b200);margin-bottom:12px;font-size:.92rem}.alert.warn{background:var(--warnbg);border-color:#fcd34d}.alert.bad{background:var(--badbg);border-color:#fca5a5}.alert.ok{background:var(--okbg);border-color:#6ee7b7}
.tabs{display:flex;gap:6px;overflow-x:auto;padding-bottom:4px;margin-bottom:14px}.tab{padding:7px 14px;border-radius:999px;border:1px solid var(--b200);background:#fff;color:var(--b700);font-weight:600;cursor:pointer;white-space:nowrap;font:inherit;font-weight:600}.tab.on{background:var(--b600);border-color:var(--b600);color:#fff}
.bar{height:10px;background:var(--b100);border-radius:999px;overflow:hidden}.bar>i{display:block;height:100%;background:linear-gradient(90deg,var(--b400),var(--b600));border-radius:999px;transition:width .4s}.bar.o>i{background:linear-gradient(90deg,#fbbf24,var(--o500))}
.pic{display:inline-flex;align-items:center;justify-content:center;width:52px;height:52px;border-radius:16px;background:linear-gradient(135deg,var(--b50),var(--b100));font-size:28px;flex:none}.pic.lg{width:84px;height:84px;font-size:46px;border-radius:24px}.pic.xl{width:120px;height:120px;font-size:68px;border-radius:30px}
.stat{display:flex;gap:12px;align-items:center}.stat b{font-size:1.5rem;color:var(--b900);display:block;line-height:1.1}
table.t{width:100%;border-collapse:collapse;font-size:.9rem}table.t th{background:var(--b50);text-align:left;padding:8px 10px;color:var(--b900);font-size:.78rem;text-transform:uppercase;letter-spacing:.03em}table.t td{padding:8px 10px;border-top:1px solid var(--line);vertical-align:top}.tw{overflow-x:auto;border:1px solid var(--line);border-radius:12px;background:#fff}
/* layout */
.top{background:#fff;border-bottom:1px solid var(--line);position:sticky;top:0;z-index:30}.top .wrap{display:flex;align-items:center;gap:14px;height:62px}
.logo{display:flex;align-items:center;gap:8px;font-weight:800;color:var(--b900);text-decoration:none!important}.logo i{width:36px;height:36px;border-radius:12px;background:linear-gradient(135deg,var(--b400),var(--b600));color:#fff;display:flex;align-items:center;justify-content:center;font-style:normal;position:relative}.logo i:after{content:"";position:absolute;top:-3px;right:-3px;width:11px;height:11px;border-radius:50%;background:var(--o500);border:2px solid #fff}
.nav{display:flex;gap:4px;margin-left:auto;align-items:center;flex-wrap:wrap}.nav a{padding:7px 12px;border-radius:10px;color:var(--b900);font-weight:600;text-decoration:none}.nav a:hover{background:var(--b50)}.nav a.on{background:var(--b100);color:var(--b700)}
.shell{display:grid;grid-template-columns:230px 1fr;min-height:calc(100vh - 62px)}.side{background:#fff;border-right:1px solid var(--line);padding:14px 10px;position:sticky;top:62px;height:calc(100vh - 62px);overflow:auto}
.side a{display:flex;gap:10px;align-items:center;padding:9px 12px;border-radius:12px;color:var(--b900);font-weight:600;text-decoration:none;margin-bottom:2px}.side a:hover{background:var(--b50)}.side a.on{background:var(--b100);color:var(--b700)}.side .sec{font-size:.7rem;text-transform:uppercase;letter-spacing:.06em;color:var(--mut);margin:14px 12px 4px}
.main{padding:20px 18px 90px;min-width:0;max-width:1000px;width:100%}
.bnav{display:none}
@media(max-width:820px){.shell{display:block}.side{display:none}.bnav{display:flex;position:fixed;bottom:0;left:0;right:0;background:#fff;border-top:1px solid var(--line);z-index:30;padding:4px 0 max(4px,env(safe-area-inset-bottom));overflow-x:auto}.bnav a{flex:1;min-width:62px;text-align:center;font-size:.68rem;padding:5px 2px;color:var(--mut);font-weight:700;text-decoration:none}.bnav a b{display:block;font-size:1.35rem;line-height:1.2}.bnav a.on{color:var(--b600)}.main{padding:14px 12px 90px}.nav .hm{display:none}h1{font-size:1.4rem}}
.hero{background:linear-gradient(160deg,var(--b100),#fff 60%);padding:36px 0 28px}.hero .wrap{display:grid;grid-template-columns:1.1fr .9fr;gap:20px;align-items:center}@media(max-width:760px){.hero .wrap{grid-template-columns:1fr}}
.hero h1{font-size:2.2rem}@media(max-width:600px){.hero h1{font-size:1.7rem}}.hero img{width:100%;max-height:340px;object-fit:contain;border-radius:24px}.hero img.up{object-fit:cover}
.sec-t{padding:30px 0}.feat{text-align:center}.feat .pic{margin:0 auto 8px}
.price{font-size:1.6rem;font-weight:800;color:var(--b700)}
footer{background:var(--b900);color:#bae6fd;padding:24px 0;margin-top:30px}footer a{color:#e0f2fe}
/* mascot */
.float{animation:fl 3s ease-in-out infinite}@keyframes fl{50%{transform:translateY(-6px)}}
.say{display:flex;gap:12px;align-items:flex-end}.say .bub{position:relative;background:#fff;border:1px solid var(--b200);border-radius:18px 18px 18px 4px;padding:10px 14px;font-size:.92rem}
.confetti{position:fixed;top:-12px;width:9px;height:14px;z-index:99;animation:cf 2.6s linear forwards;pointer-events:none}@keyframes cf{to{transform:translateY(105vh) rotate(720deg);opacity:.9}}
@media(prefers-reduced-motion:reduce){.float,.confetti{animation:none}.confetti{display:none}}
/* toast + modal */
#toasts{position:fixed;top:12px;left:50%;transform:translateX(-50%);z-index:100;display:flex;flex-direction:column;gap:8px;width:min(92vw,420px)}.toast{background:var(--b900);color:#fff;padding:10px 14px;border-radius:12px;box-shadow:0 8px 24px rgba(0,0,0,.2)}.toast.bad{background:var(--bad)}.toast.ok{background:var(--ok)}
.modal-bg{position:fixed;inset:0;background:rgba(12,74,110,.45);z-index:60;display:flex;align-items:flex-start;justify-content:center;overflow:auto;padding:30px 12px}.modal{background:#fff;border-radius:20px;padding:20px;width:min(100%,640px);box-shadow:0 20px 60px rgba(0,0,0,.3)}.modal.w{width:min(100%,900px)}
/* learning bits */
.kgrid{display:grid;grid-template-columns:repeat(auto-fill,minmax(74px,1fr));gap:8px}.kcell{border:1px solid var(--b200);border-radius:14px;background:#fff;text-align:center;padding:8px 2px;cursor:pointer;font:inherit}.kcell:hover{background:var(--b50)}.kcell b{display:block;font-size:1.9rem;line-height:1.1;color:var(--b900)}.kcell span{font-size:.72rem;color:var(--mut)}.kcell.m{background:var(--okbg);border-color:#6ee7b7}.kcell.e{visibility:hidden}
.big{font-size:3.6rem;line-height:1.1;font-weight:700;color:var(--b900)}.flash{min-height:260px;display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center;gap:6px;cursor:pointer;user-select:none}
.opt{display:block;width:100%;text-align:left;border:2px solid var(--b200);background:#fff;border-radius:14px;padding:11px 14px;margin-bottom:8px;font:inherit;cursor:pointer}.opt:hover{background:var(--b50)}.opt.sel{border-color:var(--b600);background:var(--b100)}.opt.good{border-color:var(--ok);background:var(--okbg)}.opt.wrong{border-color:var(--bad);background:var(--badbg)}
.qnav{display:flex;flex-wrap:wrap;gap:6px}.qnav button{width:34px;height:34px;border-radius:10px;border:1px solid var(--b200);background:#fff;font-weight:700;cursor:pointer}.qnav button.done{background:var(--b100)}.qnav button.cur{background:var(--b600);color:#fff}
.timer{font-variant-numeric:tabular-nums;font-weight:800;font-size:1.2rem;color:var(--b700)}.timer.low{color:var(--bad)}
ruby rt{font-size:.55em;color:var(--mut)}.furi-off ruby rt{display:none}
.prose h2{margin-top:1.2em}.prose blockquote{border-left:4px solid var(--b300);background:var(--b50);margin:10px 0;padding:8px 14px;border-radius:0 12px 12px 0}.prose table{border-collapse:collapse;width:100%;margin:10px 0}.prose th,.prose td{border:1px solid var(--line);padding:6px 10px}.prose th{background:var(--b50)}.prose code{background:var(--b50);padding:1px 6px;border-radius:6px}.prose figure{margin:14px 0}.prose figure img{display:block;margin:auto;max-height:320px;border-radius:16px;border:1px solid var(--b100);background:var(--b50)}.prose figcaption{text-align:center;font-size:.8rem;color:var(--mut)}
.chat{max-height:46vh;overflow:auto;display:flex;flex-direction:column;gap:8px;padding:6px}.msg{max-width:85%;padding:8px 12px;border-radius:14px;background:var(--b50);border:1px solid var(--b100);white-space:pre-wrap;word-wrap:break-word}.msg.me{align-self:flex-end;background:var(--b100)}.msg.host{background:var(--o100);border-color:#fed7aa}
.slide{min-height:240px;background:linear-gradient(135deg,var(--b50),#fff);border:2px solid var(--b200);border-radius:24px;padding:24px;text-align:center}.slide .body{font-size:1.6rem;white-space:pre-wrap}
.sk{height:16px;background:linear-gradient(90deg,var(--b100),var(--b50),var(--b100));border-radius:8px;margin:8px 0;animation:fl 1.2s infinite}
.canvasbox{border:2px dashed var(--b300);border-radius:16px;background:#fff;touch-action:none}
@media print{.top,.side,.bnav,#toasts{display:none!important}}