:root{
  --bg:#f6f4ef;--panel:#ffffff;--panel2:#f0ede6;--text:#1c1d21;--muted:#6b6f78;--border:#e2ddd2;
  --acc:#c2410c;--acc2:#0f766e;--good:#15803d;--bad:#b91c1c;--warn:#b45309;--hard:#a16207;--easy:#1d4ed8;
  --ink:#1c1d21;--ghost:#d9d4c8;--hl:#fde68a;--shadow:0 1px 2px rgba(0,0,0,.06),0 4px 14px rgba(0,0,0,.05);
  --kfont:"Klee One","Hiragino Mincho ProN","Yu Mincho","Noto Serif JP",serif;
  --jfont:"Hiragino Sans","Yu Gothic UI","Yu Gothic","Meiryo","Noto Sans JP",sans-serif;
}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]){
  --bg:#14161c;--panel:#1c1f27;--panel2:#252935;--text:#e9e7e1;--muted:#9aa0ab;--border:#2f3442;
  --acc:#fb923c;--acc2:#2dd4bf;--good:#4ade80;--bad:#f87171;--warn:#fbbf24;--hard:#facc15;--easy:#60a5fa;
  --ink:#f3f1ea;--ghost:#3a3f4d;--hl:#854d0e;--shadow:none}}
:root[data-theme="dark"]{
  --bg:#14161c;--panel:#1c1f27;--panel2:#252935;--text:#e9e7e1;--muted:#9aa0ab;--border:#2f3442;
  --acc:#fb923c;--acc2:#2dd4bf;--good:#4ade80;--bad:#f87171;--warn:#fbbf24;--hard:#facc15;--easy:#60a5fa;
  --ink:#f3f1ea;--ghost:#3a3f4d;--hl:#854d0e;--shadow:none}
*{box-sizing:border-box}
html,body{margin:0;background:var(--bg);color:var(--text);font:15px/1.55 system-ui,-apple-system,"Segoe UI",var(--jfont);-webkit-text-size-adjust:100%}
[hidden]{display:none!important}
button{font:inherit;color:inherit;cursor:pointer}
a{color:var(--acc2)}
.muted{color:var(--muted)}.small{font-size:12.5px}.center{text-align:center}
.jp{font-family:var(--jfont)}
.row{display:flex;gap:8px;flex-wrap:wrap;align-items:center}
.grow{flex:1}
.btn{background:var(--panel2);border:1px solid var(--border);border-radius:10px;padding:9px 14px;font-weight:600}
.btn.primary{background:var(--acc);border-color:var(--acc);color:#fff}
.btn.teal{background:var(--acc2);border-color:var(--acc2);color:#fff}
.btn.ghost{background:none}
.btn.sm{padding:5px 10px;font-size:13px;border-radius:8px}
.btn:disabled{opacity:.45;cursor:default}
.icon{background:none;border:none;font-size:18px;padding:4px 6px}

/* auth */
.auth{min-height:100vh;display:flex;align-items:center;justify-content:center;padding:16px}
.authcard{background:var(--panel);border:1px solid var(--border);border-radius:18px;padding:26px 22px;max-width:380px;width:100%;box-shadow:var(--shadow)}
.authcard h1{margin:6px 0 2px}
.authcard input{width:100%;margin:6px 0;padding:11px 12px;border-radius:10px;border:1px solid var(--border);background:var(--panel2);color:var(--text);font-size:16px}
.authcard .row{margin-top:8px}
.msg{min-height:20px;color:var(--bad);font-size:13px;margin-top:8px}
.logo{display:inline-flex;align-items:center;justify-content:center;width:46px;height:46px;border-radius:12px;background:var(--acc);color:#fff;font:600 28px/1 var(--kfont)}
.logo.sm{width:28px;height:28px;font-size:17px;border-radius:8px}

/* shell */
.top{position:sticky;top:0;z-index:20;display:flex;justify-content:space-between;align-items:center;padding:8px 16px;padding-top:calc(8px + env(safe-area-inset-top));background:var(--bg);border-bottom:1px solid var(--border)}
.brand{display:flex;gap:8px;align-items:center;font-weight:700;cursor:pointer}
.tag{font-size:11px;background:var(--panel2);border:1px solid var(--border);border-radius:6px;padding:1px 6px}
.topright{display:flex;gap:10px;align-items:center}
.cd{font-size:12.5px;color:var(--muted)}
.sync{width:8px;height:8px;border-radius:50%;background:var(--good)}
.sync.busy{background:var(--warn)}.sync.off{background:var(--bad)}
main{max-width:860px;margin:0 auto;padding:14px 16px 96px}
.tabs{position:fixed;bottom:0;left:0;right:0;z-index:20;display:flex;justify-content:space-around;background:var(--panel);border-top:1px solid var(--border);padding:4px 4px calc(4px + env(safe-area-inset-bottom))}
.tabs button{background:none;border:none;display:flex;flex-direction:column;align-items:center;gap:0;padding:4px 10px;color:var(--muted);min-width:58px}
.tabs b{font:600 20px/1.2 var(--kfont)}
.tabs span{font-size:11px}
.tabs button.on{color:var(--acc)}

/* cards and sections */
.card{background:var(--panel);border:1px solid var(--border);border-radius:14px;padding:14px;margin-bottom:12px;box-shadow:var(--shadow)}
h2{font-size:17px;margin:2px 0 10px}
h3{font-size:15px;margin:14px 0 6px}
.kpis{display:grid;grid-template-columns:repeat(auto-fit,minmax(120px,1fr));gap:10px}
.kpi{background:var(--panel2);border-radius:12px;padding:10px 12px}
.kpi .v{font-size:22px;font-weight:700}
.kpi .l{font-size:12px;color:var(--muted)}
.bar{height:8px;background:var(--panel2);border-radius:99px;overflow:hidden}
.bar i{display:block;height:100%;background:var(--acc2)}
.pill{display:inline-block;font-size:11.5px;border-radius:99px;padding:1px 8px;background:var(--panel2);border:1px solid var(--border)}
.pill.good{color:var(--good)}.pill.bad{color:var(--bad)}.pill.warn{color:var(--warn)}
.list{display:flex;flex-direction:column;gap:6px}
.li{display:flex;gap:10px;align-items:center;padding:9px 10px;border-radius:10px;background:var(--panel2);cursor:pointer}
.li .big{font:600 22px/1.2 var(--kfont);min-width:2.2em}
.seg{display:inline-flex;background:var(--panel2);border:1px solid var(--border);border-radius:99px;padding:3px;gap:2px;flex-wrap:wrap}
.seg button{background:none;border:none;padding:5px 12px;border-radius:99px;font-size:13px;color:var(--muted)}
.seg button.on{background:var(--acc);color:#fff}
input.search,select,textarea{background:var(--panel2);border:1px solid var(--border);color:var(--text);border-radius:10px;padding:8px 10px;font-size:15px}
input.search{width:100%}
table{border-collapse:collapse;width:100%;font-size:13.5px}
td,th{padding:6px 8px;border-bottom:1px solid var(--border);text-align:left;vertical-align:top}
th{color:var(--muted);font-weight:600}

/* kanji grid */
.kgrid{display:grid;grid-template-columns:repeat(auto-fill,minmax(54px,1fr));gap:6px}
.kcell{aspect-ratio:1;display:flex;align-items:center;justify-content:center;font:600 28px/1 var(--kfont);background:var(--panel2);border:2px solid transparent;border-radius:10px;cursor:pointer;position:relative}
.kcell.s0{opacity:.55}
.kcell.s1{border-color:var(--warn)}
.kcell.s2{border-color:var(--acc2)}
.kcell.s3{border-color:var(--good);background:color-mix(in srgb,var(--good) 14%,var(--panel2))}
.kcell.sel{outline:3px solid var(--acc)}
.legend{display:flex;gap:10px;flex-wrap:wrap;font-size:12px;color:var(--muted);margin:6px 0 10px}
.legend i{display:inline-block;width:10px;height:10px;border-radius:3px;margin-right:4px;vertical-align:-1px;border:2px solid}

/* kanji page */
.kpage{display:grid;grid-template-columns:minmax(220px,300px) 1fr;gap:16px;align-items:start}
@media (max-width:640px){.kpage{grid-template-columns:1fr}}
.kbox{background:var(--panel2);border-radius:16px;padding:10px;position:relative}
.kbox svg{width:100%;height:auto;display:block}
.kbox .grid line{stroke:var(--ghost);stroke-width:.4;stroke-dasharray:2 2}
.kbox .ghost path{stroke:var(--ghost)}
.kbox .ink path{stroke:var(--ink)}
.kbox .now path.cur{stroke:var(--acc)}
.kbox text{fill:var(--muted);font-size:7px;font-family:system-ui}
.kctl{display:flex;gap:6px;justify-content:center;margin-top:8px;flex-wrap:wrap}
.kw{font-size:22px;font-weight:700}
.reads{display:grid;grid-template-columns:auto 1fr;gap:4px 10px;font-size:15px}
.reads b{color:var(--muted);font-weight:600;font-size:12.5px}
.story{background:color-mix(in srgb,var(--acc) 8%,var(--panel));border-left:3px solid var(--acc);padding:8px 12px;border-radius:8px;margin:8px 0}
.comps{display:flex;gap:6px;flex-wrap:wrap}
.comp{font:600 18px/1 var(--kfont);background:var(--panel2);border-radius:8px;padding:6px 8px}
.word{display:flex;gap:10px;align-items:baseline;padding:6px 0;border-bottom:1px dashed var(--border)}
.word .w{font:600 19px/1.3 var(--jfont)}
.say{background:none;border:1px solid var(--border);border-radius:99px;font-size:12px;padding:1px 8px}
ruby rt{font-size:.55em;color:var(--muted)}
.nofuri rt{visibility:hidden}

/* drawing */
.draw{position:relative;touch-action:none;background:var(--panel2);border-radius:16px;max-width:320px;margin:0 auto}
.draw canvas,.draw svg{position:absolute;inset:0;width:100%;height:100%}
.draw:before{content:"";display:block;padding-top:100%}
.draw .hint path{stroke:var(--acc);opacity:.55}
.draw .done path{stroke:var(--ink)}

/* review */
.rv{min-height:58vh;display:flex;flex-direction:column}
.rvtop{display:flex;justify-content:space-between;font-size:12.5px;color:var(--muted);margin-bottom:8px}
.front{flex:1;display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center;padding:10px 0}
.front .huge{font:600 120px/1.1 var(--kfont)}
.front .big{font:600 44px/1.3 var(--jfont)}
.front .prompt{color:var(--muted);font-size:13px;margin-top:6px}
.back{border-top:1px solid var(--border);padding-top:10px;margin-top:6px}
.grades{display:grid;grid-template-columns:repeat(4,1fr);gap:6px;position:sticky;bottom:calc(64px + env(safe-area-inset-bottom));margin-top:12px}
.grades button{border:none;border-radius:12px;padding:10px 4px;color:#fff;font-weight:700;line-height:1.2}
.grades small{display:block;font-weight:500;opacity:.85;font-size:11px}
.g1{background:var(--bad)}.g2{background:var(--hard)}.g3{background:var(--good)}.g4{background:var(--easy)}
.answer{width:100%;max-width:340px;font-size:22px;text-align:center;padding:10px;border-radius:12px;border:2px solid var(--border);background:var(--panel2);color:var(--text)}
.answer.ok{border-color:var(--good)}.answer.no{border-color:var(--bad)}
.tgt{background:var(--hl);border-radius:4px;padding:0 2px}
.u{text-decoration:underline;text-underline-offset:4px;text-decoration-thickness:2px}

/* quiz / exam */
.q{padding:12px 0;border-bottom:1px solid var(--border)}
.q .stem{font:16.5px/1.9 var(--jfont)}
.opts{display:grid;gap:6px;margin-top:8px}
.opts.four{grid-template-columns:1fr 1fr}
@media (max-width:520px){.opts.four{grid-template-columns:1fr}}
.opt{display:flex;gap:8px;align-items:flex-start;text-align:left;background:var(--panel2);border:2px solid transparent;border-radius:10px;padding:8px 10px;font:15.5px/1.6 var(--jfont)}
.opt .n{font-weight:700;color:var(--muted);min-width:1.2em}
.opt.pick{border-color:var(--acc)}
.opt.right{border-color:var(--good);background:color-mix(in srgb,var(--good) 12%,var(--panel2))}
.opt.wrong{border-color:var(--bad)}
.why{font-size:13.5px;background:var(--panel2);border-radius:8px;padding:6px 10px;margin-top:6px}
.passage{font:15.5px/1.95 var(--jfont);background:var(--panel2);border-radius:10px;padding:12px;white-space:pre-wrap}
.mondai{font-weight:700;margin:16px 0 4px;color:var(--acc)}
.inst{font:13.5px/1.7 var(--jfont);color:var(--muted)}
.sheetnav{display:flex;flex-wrap:wrap;gap:4px;margin:8px 0}
.sheetnav button{width:30px;height:30px;border-radius:8px;border:1px solid var(--border);background:var(--panel2);font-size:12px;padding:0}
.sheetnav button.ans{background:var(--acc2);color:#fff;border-color:var(--acc2)}
.sheetnav button.flag{outline:2px solid var(--warn)}
.timer{font-variant-numeric:tabular-nums;font-weight:700}
.timer.low{color:var(--bad)}
.order{display:flex;gap:6px;flex-wrap:wrap;margin:8px 0}
.slots{display:flex;gap:6px;flex-wrap:wrap;align-items:center;font:16px/2 var(--jfont)}
.slot{min-width:64px;min-height:34px;border-bottom:2px solid var(--muted);text-align:center;padding:0 4px}
.slot.star{border-bottom-color:var(--acc)}
.piece{background:var(--panel2);border:1px solid var(--border);border-radius:8px;padding:4px 10px;font:15.5px/1.6 var(--jfont)}
.piece.used{opacity:.3}
.score{font-size:40px;font-weight:800}
.verdict{font-size:20px;font-weight:800}
.verdict.pass{color:var(--good)}.verdict.fail{color:var(--bad)}
.player{display:flex;gap:8px;align-items:center;background:var(--panel2);border-radius:12px;padding:10px;position:sticky;top:56px;z-index:5}
.script{font:14.5px/1.8 var(--jfont)}
.script .sp{font-weight:700;color:var(--muted);margin-right:6px}

/* heatmap + charts */
.heat{display:grid;grid-template-columns:repeat(15,1fr);gap:3px}
.heat i{aspect-ratio:1;border-radius:3px;background:var(--panel2)}
.cols{display:flex;align-items:flex-end;gap:3px;height:80px}
.cols i{flex:1;background:var(--acc2);border-radius:3px 3px 0 0;min-height:2px;position:relative}
.cols i span{position:absolute;bottom:-16px;left:0;right:0;text-align:center;font-size:9px;color:var(--muted);font-style:normal}

/* modal + toast */
.modal{position:fixed;inset:0;z-index:50;background:rgba(0,0,0,.45);display:flex;align-items:flex-end;justify-content:center}
.sheet{background:var(--bg);width:100%;max-width:860px;max-height:92vh;overflow:auto;border-radius:18px 18px 0 0;padding:16px 16px calc(24px + env(safe-area-inset-bottom))}
@media (min-width:700px){.modal{align-items:center}.sheet{border-radius:18px}}
.toast{position:fixed;left:50%;bottom:90px;transform:translateX(-50%);background:var(--text);color:var(--bg);padding:8px 14px;border-radius:10px;font-size:13.5px;opacity:0;transition:opacity .2s;pointer-events:none;z-index:60;max-width:90vw}
.toast.on{opacity:1}
.spin{display:inline-block;width:14px;height:14px;border:2px solid var(--border);border-top-color:var(--acc);border-radius:50%;animation:sp 0.8s linear infinite;vertical-align:-2px}
@keyframes sp{to{transform:rotate(360deg)}}