:root{--bg:#f4f8ff;--card:#fff;--ink:#182333;--muted:#64748b;--primary:#2563eb;--accent:#f59e0b;--good:#16a34a;--bad:#dc2626;--line:#dbe7ff;--soft:#eff6ff}body.dark{--bg:#0f172a;--card:#172033;--ink:#e5e7eb;--muted:#a5b4fc;--line:#334155;--soft:#1e293b}*{box-sizing:border-box}body{margin:0;font-family:Segoe UI,Arial,'Noto Sans JP',sans-serif;background:linear-gradient(135deg,#e0f2fe,#fef3c7);color:var(--ink)}body.dark{background:#0f172a}.topbar{display:flex;justify-content:space-between;align-items:center;padding:18px 26px;background:#0f172a;color:white;position:sticky;top:0;z-index:5;box-shadow:0 4px 20px #0003}.brand{display:flex;gap:14px;align-items:center}.logo{width:56px;height:56px;border-radius:18px;background:linear-gradient(135deg,#f59e0b,#ef4444);display:grid;place-items:center;font-size:34px;font-weight:900}.topbar h1{margin:0;font-size:24px}.topbar p{margin:3px 0 0;color:#cbd5e1}.top-actions{display:flex;gap:8px}main{max-width:1280px;margin:auto;padding:24px}.card,.card-lite{background:var(--card);border-radius:24px;padding:22px;box-shadow:0 10px 30px #1e3a8a20;border:1px solid #ffffff55}.card-lite{box-shadow:none;border:1px solid var(--line);margin:18px 0}.hero{display:flex;justify-content:space-between;gap:20px;margin-bottom:20px}.hero h2{font-size:30px;margin:0 0 8px}.hero p,.hint{color:var(--muted)}.stats{display:flex;gap:12px}.stats div{min-width:105px;background:var(--soft);border-radius:20px;padding:18px;text-align:center}.stats strong{display:block;font-size:28px;color:var(--primary)}.stats span{font-size:13px;color:var(--muted)}.controls{display:flex;gap:10px;align-items:center;margin-bottom:20px;flex-wrap:wrap}.tab,button{border:0;border-radius:14px;background:var(--primary);color:#fff;padding:12px 16px;font-weight:800;cursor:pointer;transition:.2s}.tab.active,.mode.active{background:var(--accent);color:#111827}.ghost{background:#e2e8f0;color:#0f172a}.tiny{padding:4px 8px;border-radius:9px;font-size:12px}button:hover{transform:translateY(-1px);filter:brightness(1.05)}input,select{padding:12px 14px;border-radius:14px;border:1px solid var(--line);font-size:15px;min-width:220px;background:var(--card);color:var(--ink)}input[type=range]{min-width:120px;padding:0}.layout{display:grid;grid-template-columns:330px 1fr;gap:20px}.kanji-list h3{margin-top:0}#kanjiGrid{display:grid;grid-template-columns:repeat(5,1fr);gap:8px;max-height:760px;overflow:auto;padding-right:4px}.kanji-cell{height:50px;border-radius:14px;background:var(--soft);border:1px solid var(--line);display:grid;place-items:center;font-size:28px;cursor:pointer;position:relative}.kanji-cell.active{background:#dbeafe;border-color:#2563eb;color:#0f172a}.kanji-cell.learned::after{content:'★';position:absolute;right:4px;top:2px;color:#f59e0b;font-size:14px}.main-card{min-height:760px}.study-grid{display:grid;grid-template-columns:330px 1fr;gap:20px}.kanji-display{font-size:190px;line-height:1;text-align:center;font-weight:900;color:#111827;background:radial-gradient(circle,#fff7ed,#eff6ff);border-radius:28px;padding:25px;margin-bottom:10px}.mini-actions{display:flex;gap:8px;justify-content:center;flex-wrap:wrap}.info{font-size:18px;line-height:1.55}.info h2{font-size:42px;margin:0}.actions{display:flex;gap:10px;flex-wrap:wrap;margin:18px 0}.voice-panel{display:grid;grid-template-columns:1fr 1fr 1fr;gap:12px}.voice-panel h3{grid-column:1/-1;margin:0}.voice-panel label{display:flex;flex-direction:column;gap:6px;font-weight:800}.writing-head{display:flex;justify-content:space-between;align-items:center;gap:10px;flex-wrap:wrap}.write-layout{display:grid;grid-template-columns:minmax(440px,480px) 1fr;gap:22px;align-items:start}.stroke-card{background:var(--soft);border-radius:22px;padding:12px;border:1px solid var(--line)}#strokeSvg{width:100%;height:460px;background:#fff;border-radius:20px;border:2px solid #dbeafe;display:block;overflow:visible}.stroke-buttons,.canvas-tools{display:flex;gap:8px;margin-top:10px;flex-wrap:wrap}canvas{width:100%;height:460px;background:#fff;border:3px solid #bfdbfe;border-radius:22px;touch-action:none;display:block}.feedback{font-size:18px;font-weight:900;color:var(--primary)}.hidden{display:none}.quiz-kanji{font-size:150px;text-align:center;margin:10px}.quiz-audio{text-align:center;margin-bottom:12px}.answers{display:grid;grid-template-columns:repeat(2,minmax(160px,1fr));gap:12px}.answers button{font-size:18px;background:#334155}.answers button.correct{background:var(--good)}.answers button.wrong{background:var(--bad)}#quizFeedback{font-size:20px;font-weight:900;min-height:30px}footer{text-align:center;color:#475569;padding:20px}.stroke-path{fill:none;stroke:#1f2937;stroke-width:10;stroke-linecap:round;stroke-linejoin:round;vector-effect:non-scaling-stroke}.stroke-bg{fill:none;stroke:#cbd5e1;stroke-width:12;stroke-linecap:round;stroke-linejoin:round;vector-effect:non-scaling-stroke}.stroke-num{font:bold 18px Arial;fill:#2563eb;paint-order:stroke;stroke:white;stroke-width:2px}.start-dot{fill:#ef4444;stroke:white;stroke-width:1.5}.arrow{fill:#f59e0b;stroke:white;stroke-width:1}.kvg-mode .stroke-path{stroke-width:4.2}.kvg-mode .stroke-bg{stroke-width:5.2}.kvg-mode .stroke-num{font-size:6.5px;stroke-width:.7px}.kvg-mode .start-dot{r:2.2}.kvg-mode .arrow{transform-box:fill-box}.canvas-tools button{min-width:90px}@media(max-width:980px){.hero,.layout,.study-grid,.write-layout{display:block}.stats{margin-top:12px}.kanji-list{margin-bottom:20px}.voice-panel{grid-template-columns:1fr}.write-layout>div{margin-bottom:14px}#kanjiGrid{grid-template-columns:repeat(8,1fr)}.kanji-display{font-size:130px}.answers{grid-template-columns:1fr}.topbar{display:block}.top-actions{margin-top:10px}}
.stroke-path.active-stroke{stroke:#ef4444;filter:drop-shadow(0 0 6px #f59e0b)}
.stroke-card .hint{font-size:13px;line-height:1.35}
#writingFeedback{background:#eff6ff;border:1px solid #bfdbfe;border-radius:14px;padding:12px;min-height:54px;line-height:1.45}
body.dark #writingFeedback{background:#111827;border-color:#334155}

.speed-buttons{display:flex;gap:8px;align-items:end;flex-wrap:wrap}.speed-buttons button{padding:10px 12px}.feedback-badge{display:inline-block;margin-top:12px;padding:10px 16px;border-radius:999px;background:#ecfdf5;color:#166534;font-weight:900;border:2px solid #bbf7d0;box-shadow:0 6px 18px #22c55e20}.feedback-badge.try{background:#fff7ed;color:#9a3412;border-color:#fed7aa}.feedback-badge.great{background:#eff6ff;color:#1d4ed8;border-color:#bfdbfe}.feedback-badge.correct{background:#f0fdf4;color:#15803d;border-color:#86efac}.practice-note{color:#64748b;font-size:13px}
.examples-box{margin-top:10px;padding:12px;border-radius:16px;background:#f8fafc;border:1px solid #e5e7eb}
.example-row{margin-top:8px;padding:8px;border-radius:12px;background:white;line-height:1.45}
.example-row .jp{font-size:1.05rem;font-weight:700;color:#111827}
#writeCanvas{background:#fff;border:3px solid #dbeafe;border-radius:22px;box-shadow:inset 0 0 0 1px #e5e7eb;max-width:100%}
.dark .examples-box{background:#1f2937;border-color:#334155}.dark .example-row{background:#111827}.dark .example-row .jp{color:#f8fafc}

/* PWA/mobile refinements */
html { -webkit-text-size-adjust: 100%; }
body { min-height: 100vh; min-height: 100dvh; }
button, input, select { font-size: 16px; }
button { -webkit-tap-highlight-color: transparent; }
@media (max-width: 760px) {
  main { padding: 12px; }
  .topbar { padding: 14px; position: static; }
  .brand { align-items: flex-start; }
  .logo { width: 46px; height: 46px; font-size: 28px; border-radius: 14px; }
  .topbar h1 { font-size: 20px; }
  .topbar p { font-size: 12px; }
  .card, .card-lite { border-radius: 18px; padding: 14px; }
  .hero h2 { font-size: 22px; }
  .stats { display: grid; grid-template-columns: repeat(3,1fr); gap: 8px; }
  .stats div { min-width: 0; padding: 10px; }
  .stats strong { font-size: 22px; }
  .controls { gap: 8px; }
  .controls input, .controls select { width: 100%; min-width: 0; }
  #kanjiGrid { grid-template-columns: repeat(6,1fr); max-height: 260px; }
  .kanji-cell { height: 46px; font-size: 26px; }
  .main-card { min-height: auto; }
  .kanji-display { font-size: 110px; padding: 18px; }
  .info { font-size: 16px; }
  .info h2 { font-size: 34px; }
  .voice-panel { gap: 10px; }
  .writing-head { align-items: stretch; }
  .writing-head > div { display: grid; grid-template-columns: repeat(3,1fr); width: 100%; gap: 6px; }
  #strokeSvg { height: 320px; }
  canvas { height: 360px; }
  .canvas-tools, .stroke-buttons, .mini-actions, .actions, .speed-buttons { display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); }
  .answers { grid-template-columns: 1fr; }
  .quiz-kanji { font-size: 100px; }
}
@media (max-width: 430px) {
  #kanjiGrid { grid-template-columns: repeat(5,1fr); }
  .stats { grid-template-columns: 1fr 1fr 1fr; }
  .stats span { font-size: 11px; }
  .kanji-display { font-size: 92px; }
  #strokeSvg { height: 280px; }
  canvas { height: 320px; }
}

/* Professional mobile/web app polish */
:root{--safe-top:env(safe-area-inset-top);--safe-bottom:env(safe-area-inset-bottom)}
.install-banner{position:sticky;top:0;z-index:20;margin:0 auto;padding:10px 14px;background:#111827;color:#fff;display:flex;gap:10px;align-items:center;justify-content:center;box-shadow:0 6px 24px #0003}.install-banner.hidden{display:none}.install-banner button{padding:9px 12px}.install-banner .ghost{background:#374151;color:#fff}.topbar{padding-top:calc(14px + var(--safe-top))}.bottom-nav{position:fixed;bottom:0;left:0;right:0;background:#fff;border-top:1px solid #e5e7eb;display:none;grid-template-columns:repeat(4,1fr);z-index:15;padding:6px 8px calc(6px + var(--safe-bottom));box-shadow:0 -8px 20px #0001}.bottom-nav button{background:transparent;color:#334155;padding:8px 4px;border-radius:12px;font-size:12px;display:flex;flex-direction:column;gap:2px;align-items:center}.bottom-nav button.active{background:#eff6ff;color:#1d4ed8}.app-shell{max-width:1280px;margin:auto}.example-row ruby{ruby-position:over}.example-row rt{font-size:.62em;color:#64748b;font-weight:600}.main-card{overflow:hidden}.write-layout>div{min-width:0}.stroke-card,#writeCanvas{max-width:100%}.voice-panel select{width:100%;min-width:0}.controls .tab{white-space:normal}.kanji-cell{user-select:none;-webkit-user-select:none}.info p{word-break:break-word}.jp{font-family:'Yu Gothic','Hiragino Sans','Noto Sans JP',sans-serif}.dark .bottom-nav{background:#111827;border-color:#334155}.dark .bottom-nav button{color:#cbd5e1}.dark .bottom-nav button.active{background:#1e3a8a;color:white}
@media(max-width:760px){body{padding-bottom:76px}.bottom-nav{display:grid}.topbar{border-radius:0 0 22px 22px}.top-actions{display:grid;grid-template-columns:1fr 1fr}.layout{gap:12px}.kanji-list.card{padding-bottom:10px}.kanji-list h3{display:flex;align-items:center;justify-content:space-between}.study-grid{gap:12px}.kanji-panel{position:relative}.mini-actions button,.actions button,.canvas-tools button,.stroke-buttons button{min-height:44px}.write-layout{gap:12px}.stroke-card{padding:10px}.voice-panel.card-lite{padding:12px}.examples-box{max-height:320px;overflow:auto}.feedback-badge{width:100%;text-align:center}.answers button{min-height:56px}.card{box-shadow:0 4px 18px #1e3a8a18}.controls.card{position:sticky;top:0;z-index:4;background:rgba(255,255,255,.92);backdrop-filter:blur(12px)}body.dark .controls.card{background:rgba(23,32,51,.92)}}
@media(max-width:520px){.hero{margin-bottom:12px}.hero h2{font-size:20px}.hero p{font-size:14px}.stats{grid-template-columns:repeat(3,1fr)}.controls .tab{width:calc(50% - 4px);font-size:14px;padding:10px 8px}.info{font-size:15px}.info h2{font-size:30px}.kanji-display{font-size:84px}.voice-panel label{font-size:14px}#strokeSvg{height:260px}canvas{height:300px}.writing-head h3{font-size:18px}.writing-head>div{grid-template-columns:repeat(3,1fr)}.mode{padding:10px 6px}.canvas-tools,.stroke-buttons,.mini-actions,.actions,.speed-buttons{grid-template-columns:1fr 1fr}.topbar p{display:none}}