:root{--font-sans: "Inter", "Noto Sans JP", system-ui, -apple-system, sans-serif;--radius: 16px;--radius-sm: 10px;--gap: 16px;--maxw: 560px;--tap: 48px;--transition: .18s ease;--again: #e5484d;--hard: #e2a336;--good: #30a46c;--easy: #5b8def}[data-theme=dark]{--bg: #0f1115;--bg-elev: #181b22;--bg-elev2: #21252e;--border: #2a2f3a;--text: #e8eaed;--text-dim: #9aa0aa;--text-faint: #6b7280;--accent: #6ea8fe;--accent-soft: #1d2735;--shadow: 0 6px 24px rgba(0, 0, 0, .45);--heat-0: #21252e;--heat-1: #16432c;--heat-2: #1e6b42;--heat-3: #2c9c5f;--heat-4: #46d088}[data-theme=light]{--bg: #f5f6f8;--bg-elev: #ffffff;--bg-elev2: #eef0f3;--border: #dfe3e8;--text: #1a1d23;--text-dim: #5c636e;--text-faint: #97a0ac;--accent: #2f6fed;--accent-soft: #e6eefe;--shadow: 0 6px 20px rgba(20, 30, 50, .1);--heat-0: #e9ecf0;--heat-1: #c6e8d2;--heat-2: #88d3a6;--heat-3: #46b377;--heat-4: #1f8f54}*{box-sizing:border-box}html,body{margin:0;padding:0}body{font-family:var(--font-sans);background:var(--bg);color:var(--text);line-height:1.5;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility;overscroll-behavior-y:none}button{font-family:inherit;cursor:pointer}a{color:var(--accent)}#app{max-width:var(--maxw);margin:0 auto;padding:16px 16px calc(80px + env(safe-area-inset-bottom));min-height:100vh}.view-title{font-size:1.4rem;font-weight:700;margin:8px 0 4px}.view-sub{color:var(--text-dim);font-size:.9rem;margin:0 0 20px}.card-box{background:var(--bg-elev);border:1px solid var(--border);border-radius:var(--radius);padding:18px;margin-bottom:var(--gap);box-shadow:var(--shadow)}.row{display:flex;align-items:center;gap:12px}.row.between{justify-content:space-between}.grid2{display:grid;grid-template-columns:1fr 1fr;gap:12px}.muted{color:var(--text-dim)}.faint{color:var(--text-faint)}.big-num{font-size:2rem;font-weight:700;line-height:1.1}.pill{display:inline-block;padding:2px 10px;border-radius:999px;font-size:.75rem;font-weight:600;background:var(--bg-elev2);color:var(--text-dim)}.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:var(--tap);padding:0 18px;border:1px solid var(--border);border-radius:var(--radius-sm);background:var(--bg-elev2);color:var(--text);font-size:1rem;font-weight:600;transition:filter var(--transition),transform var(--transition)}.btn:active{transform:scale(.97)}.btn.primary{background:var(--accent);border-color:var(--accent);color:#fff}.btn.full{width:100%}.btn.ghost{background:transparent}.progress{height:10px;background:var(--bg-elev2);border-radius:999px;overflow:hidden}.progress>span{display:block;height:100%;background:linear-gradient(90deg,var(--accent),var(--good));transition:width .4s ease}.tabbar{position:fixed;bottom:0;left:0;right:0;display:flex;justify-content:space-around;background:var(--bg-elev);border-top:1px solid var(--border);padding:6px 4px calc(6px + env(safe-area-inset-bottom));z-index:50}.tabbar a{flex:1;text-align:center;text-decoration:none;color:var(--text-faint);font-size:.7rem;padding:4px 0;border-radius:8px}.tabbar a .ico{display:block;font-size:1.25rem;line-height:1.4}.tabbar a.active{color:var(--accent)}.input,select.input{width:100%;min-height:var(--tap);padding:0 12px;background:var(--bg);border:1px solid var(--border);border-radius:var(--radius-sm);color:var(--text);font-size:1rem}textarea.input{min-height:72px;padding:10px 12px;resize:vertical}label.field{display:block;margin-bottom:14px}label.field>.lab{display:block;font-size:.85rem;color:var(--text-dim);margin-bottom:6px}input[type=range]{width:100%;accent-color:var(--accent);height:var(--tap)}.toast{position:fixed;left:50%;bottom:calc(86px + env(safe-area-inset-bottom));transform:translate(-50%);background:var(--bg-elev2);border:1px solid var(--border);color:var(--text);padding:10px 16px;border-radius:999px;font-size:.85rem;box-shadow:var(--shadow);z-index:100;opacity:0;transition:opacity var(--transition);pointer-events:none}.toast.show{opacity:1}details.advanced{border:1px solid var(--border);border-radius:var(--radius-sm);padding:12px 14px;margin-bottom:var(--gap)}details.advanced summary{cursor:pointer;font-weight:600;color:var(--text-dim)}.study-wrap{display:flex;flex-direction:column;min-height:calc(100vh - 110px)}.study-top{margin-bottom:12px}.study-progress-line{display:flex;align-items:center;gap:10px;font-size:.8rem;color:var(--text-dim)}.flashcard{flex:1;display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center;background:var(--bg-elev);border:1px solid var(--border);border-radius:var(--radius);padding:28px 20px;box-shadow:var(--shadow);min-height:300px;user-select:none;cursor:pointer}.flashcard .prompt-word{font-size:2.4rem;font-weight:700;letter-spacing:-.01em}.flashcard .prompt-pos{margin-top:6px;color:var(--text-faint);font-size:.9rem}.flashcard .answer{margin-top:18px;padding-top:18px;border-top:1px solid var(--border);width:100%}.flashcard .answer .trans{font-size:1.5rem;font-weight:600}.flashcard .reading{margin-top:6px;font-size:1rem;color:var(--accent);letter-spacing:.02em}.flashcard .answer .ex{margin-top:14px;font-size:.95rem;color:var(--text-dim);line-height:1.6}.flashcard .answer .ex .en{color:var(--text)}.flashcard .tap-hint{margin-top:20px;font-size:.8rem;color:var(--text-faint)}.cefr-tag{position:absolute;top:12px;right:14px}.rate-row{display:grid;grid-template-columns:repeat(4,1fr);gap:8px;margin-top:14px}.rate-btn{display:flex;flex-direction:column;align-items:center;gap:2px;min-height:60px;border:none;border-radius:var(--radius-sm);color:#fff;font-weight:700;padding:6px 2px}.rate-btn .when{font-size:.68rem;font-weight:500;opacity:.92}.rate-btn .key{font-size:.6rem;opacity:.7}.rate-btn[data-r="1"]{background:var(--again)}.rate-btn[data-r="2"]{background:var(--hard)}.rate-btn[data-r="3"]{background:var(--good)}.rate-btn[data-r="4"]{background:var(--easy)}.session-done{text-align:center;padding:40px 20px}.session-done .emoji{font-size:3rem}.sleep-note{background:var(--accent-soft);border:1px solid var(--border);border-radius:var(--radius-sm);padding:14px 16px;color:var(--text);font-size:.92rem;margin:16px 0}.chunk-break{text-align:center;padding:30px 20px}.heatmap{display:grid;grid-auto-flow:column;grid-template-rows:repeat(7,1fr);gap:3px;overflow-x:auto;padding-bottom:4px}.heatmap .cell{width:13px;height:13px;border-radius:3px;background:var(--heat-0)}.heatmap .cell[data-lv="1"]{background:var(--heat-1)}.heatmap .cell[data-lv="2"]{background:var(--heat-2)}.heatmap .cell[data-lv="3"]{background:var(--heat-3)}.heatmap .cell[data-lv="4"]{background:var(--heat-4)}.state-table{width:100%;border-collapse:collapse;font-size:.85rem}.state-table th,.state-table td{text-align:left;padding:8px 6px;border-bottom:1px solid var(--border)}.state-table th{color:var(--text-dim);font-weight:600;position:sticky;top:0;background:var(--bg)}.state-scroll{max-height:360px;overflow-y:auto}.diag-choice{display:block;width:100%;text-align:left;margin-bottom:10px;min-height:var(--tap);padding:12px 14px;background:var(--bg-elev);border:1px solid var(--border);border-radius:var(--radius-sm);color:var(--text);font-size:1rem;transition:background var(--transition),border-color var(--transition)}.diag-choice:active{background:var(--accent-soft)}.diag-choice.correct{border-color:var(--good);background:#30a46c24}.diag-choice.wrong{border-color:var(--again);background:#e5484d24}.strength-bar{display:flex;align-items:center;gap:8px;margin-bottom:8px;font-size:.85rem}.strength-bar .track{flex:1;height:8px;background:var(--bg-elev2);border-radius:999px;overflow:hidden}.strength-bar .track>span{display:block;height:100%;background:var(--good)}.line-chart{width:100%;height:auto;display:block}