:root{--bg: #fafbfc;--surface: #ffffff;--ink: #111827;--ink-soft: #5b6478;--muted: #6b7280;--border: #e3e8f2;--brand: #4f46e5;--brand-hover: #4338ca;--accent: #f59e0b;--shadow-soft: 0 16px 36px rgba(15, 23, 42, .09);--shadow-card: 0 10px 24px rgba(15, 23, 42, .08);--font-ui: "Inter", "Nunito", "Noto Sans JP", "Hiragino Sans", "Yu Gothic", system-ui, sans-serif;--radius: 16px;--radius-sm: 10px}*,*:before,*:after{box-sizing:border-box;margin:0;padding:0}html{font-family:var(--font-ui);color:var(--ink);background:var(--bg);-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}body{min-height:100dvh}.page{max-width:720px;margin:0 auto;padding:0 16px 32px;display:flex;flex-direction:column;min-height:100dvh}.app-header{display:flex;align-items:center;justify-content:space-between;padding:16px 0;gap:12px;flex-wrap:wrap}.app-header-left{display:flex;align-items:center;gap:12px;flex-wrap:wrap}.brand-mark{display:flex;align-items:center;gap:6px;text-decoration:none;color:var(--brand);font-weight:800;font-size:1rem}.brand-logo{width:28px;height:28px}.app-header-title{font-family:"Nunito",var(--font-ui);font-size:clamp(1.1rem,3vw,1.4rem);font-weight:800;color:var(--ink)}.locale-select-wrap{display:flex;align-items:center;gap:6px}.locale-select-label{font-size:.8rem;color:var(--muted)}.locale-select{font-family:var(--font-ui);font-size:.85rem;padding:6px 10px;border:1.5px solid var(--border);border-radius:8px;background:var(--surface);color:var(--ink);cursor:pointer;min-height:36px}.locale-select:focus-visible{outline:2px solid var(--brand);outline-offset:2px}.main-content{flex:1;display:flex;flex-direction:column;align-items:center;gap:20px;padding:16px 0}.calc-hint{font-size:1.05rem;color:var(--ink-soft);text-align:center;min-height:1.5em}.formula-display{display:flex;align-items:center;gap:12px;flex-wrap:wrap;justify-content:center}.formula-box{width:64px;height:64px;display:flex;align-items:center;justify-content:center;font-family:"Nunito",var(--font-ui);font-size:2rem;font-weight:800;border:3px solid var(--border);border-radius:var(--radius-sm);background:var(--surface);color:var(--muted);cursor:pointer;transition:all .15s ease}.formula-box--active{border-color:var(--brand);box-shadow:0 0 0 3px #4f46e526}.formula-box--filled{color:var(--ink)}.formula-op{font-family:"Nunito",var(--font-ui);font-size:2rem;font-weight:800;color:var(--ink-soft)}.formula-eq{font-family:"Nunito",var(--font-ui);font-size:2rem;font-weight:800;width:64px;height:64px;display:flex;align-items:center;justify-content:center;border:3px solid var(--brand);border-radius:var(--radius-sm);background:var(--brand);color:#fff;cursor:pointer;transition:all .15s ease}.formula-eq:disabled{opacity:.4;cursor:not-allowed}.formula-eq:not(:disabled):hover{background:var(--brand-hover)}.formula-eq--done{opacity:.5}.formula-result{font-family:"Nunito",var(--font-ui);font-size:2.8rem;font-weight:800;color:var(--muted);min-width:64px;text-align:center;transition:all .3s ease}.formula-result--show{color:var(--brand);animation:pop-in .3s ease}.dot-groups{display:flex;align-items:center;gap:16px;justify-content:center;min-height:80px;padding:16px;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow-card);width:100%;max-width:400px}.dot-groups--merged{justify-content:center}.dot-group{display:flex;align-items:center;justify-content:center}.dot-group-plus{font-family:"Nunito",var(--font-ui);font-size:1.5rem;font-weight:800;color:var(--muted)}.dot--pop{animation:dot-pop .3s ease both}.dot--merge{animation:dot-merge .4s ease both}@keyframes dot-pop{0%{r:0;opacity:0}to{r:10;opacity:1}}@keyframes dot-merge{0%{opacity:0;transform:translateY(-8px)}to{opacity:1;transform:translateY(0)}}.number-pad{display:grid;grid-template-columns:repeat(3,1fr);gap:8px;width:100%;max-width:280px}.number-pad-btn{font-family:"Nunito",var(--font-ui);font-size:1.5rem;font-weight:800;min-height:56px;border:2px solid var(--border);border-radius:var(--radius-sm);background:var(--surface);color:var(--ink);cursor:pointer;transition:all .15s ease}.number-pad-btn:hover:not(:disabled){border-color:var(--brand);color:var(--brand);transform:translateY(-2px);box-shadow:var(--shadow-card)}.number-pad-btn:active:not(:disabled){transform:scale(.96)}.number-pad-btn:disabled{opacity:.3;cursor:not-allowed}.calc-actions{display:flex;gap:12px}.reset-btn{font-family:var(--font-ui);font-size:.95rem;font-weight:600;padding:10px 24px;border:1.5px solid var(--border);border-radius:20px;background:var(--surface);color:var(--ink-soft);cursor:pointer;min-height:44px;transition:all .15s ease}.reset-btn:hover{border-color:var(--brand);color:var(--brand)}.modal-backdrop{position:fixed;top:0;right:0;bottom:0;left:0;background:#00000073;-webkit-backdrop-filter:blur(4px);backdrop-filter:blur(4px);display:flex;align-items:center;justify-content:center;z-index:100;padding:16px}.card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow-soft)}.app-modal{width:100%;max-width:480px;max-height:80vh;overflow-y:auto;padding:24px;animation:pop-in .2s ease}.app-modal-header{display:flex;align-items:center;justify-content:space-between;margin-bottom:16px}.app-modal-header h2{font-size:1.2rem;font-weight:700}.app-modal-close{font-family:var(--font-ui);font-size:.85rem;padding:6px 14px;border:1.5px solid var(--border);border-radius:8px;background:var(--surface);color:var(--muted);cursor:pointer}.app-modal-body{font-size:.95rem;line-height:1.7;color:var(--ink-soft)}.app-modal-body p{margin-bottom:12px}.app-modal-body ol{padding-left:1.5em}.app-modal-body li{margin-bottom:8px}.site-footer{margin-top:auto;padding:24px 0 16px;border-top:1px solid var(--border);display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:12px}.site-footer-brand{display:flex;align-items:center;gap:12px}.site-footer-copy{font-size:.75rem;color:var(--muted)}.site-footer-links{display:flex;align-items:center;gap:12px;flex-wrap:wrap}.site-footer-link,.site-footer-button{font-family:var(--font-ui);font-size:.8rem;color:var(--muted);text-decoration:none;background:none;border:none;cursor:pointer;padding:4px 0}.site-footer-link:hover,.site-footer-button:hover{color:var(--brand)}@keyframes pop-in{0%{opacity:0;transform:scale(.92)}to{opacity:1;transform:scale(1)}}@media (max-width: 480px){.formula-box,.formula-eq{width:52px;height:52px;font-size:1.6rem}.formula-result{font-size:2.2rem}.number-pad{max-width:240px}.site-footer{flex-direction:column;align-items:flex-start}}