:root{color-scheme:light;--paper:#f5f4ef;--surface:#fbfaf6;--ink:#222824;--muted:#687069;--line:#cfd3cc;--line-strong:#9fa79f;--accent:#245b49;--accent-soft:#e2ebe5;--danger:#9b2f2f;--danger-soft:#f8e9e7;font-family:ui-sans-serif,system-ui,-apple-system,"Segoe UI","Noto Sans JP",sans-serif}*{box-sizing:border-box}body{margin:0;color:var(--ink);background:var(--paper);line-height:1.65}button,input,select{font:inherit}a{color:inherit}:focus-visible{outline:3px solid var(--accent);outline-offset:3px}.eyebrow,.section-kicker{margin:0 0 5px;color:var(--accent);font-size:.78rem;font-weight:780;letter-spacing:.08em;text-transform:uppercase}h2{margin:0;font-size:clamp(1.2rem,2vw,1.48rem)}h3{margin:0;font-size:1rem}.tool-shell{display:grid;grid-template-columns:minmax(0,.98fr) minmax(0,1.02fr);border:1px solid var(--line-strong);background:var(--surface)}.calculator-panel,.visual-panel{min-width:0;padding:24px}.calculator-panel{border-right:1px solid var(--line)}fieldset{margin:17px 0 0;padding:0;border:0}legend{margin-bottom:8px;font-weight:760}.mode-options{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:6px}.mode-options label{position:relative;cursor:pointer}.mode-options input{position:absolute;opacity:0}.mode-options span{min-height:48px;display:grid;place-items:center;padding:7px;border:1px solid var(--line);color:var(--muted);text-align:center;font-size:.87rem;font-weight:700}.mode-options input:checked+span{border-color:var(--accent);background:var(--accent-soft);color:var(--accent)}.mode-options input:focus-visible+span{outline:3px solid var(--accent);outline-offset:2px}.values-fieldset{margin-top:20px}.input-grid{display:grid;gap:14px}.input-row label{display:block;margin-bottom:5px;font-weight:720}.input-wrap{display:grid;grid-template-columns:minmax(0,1fr) minmax(110px,.42fr);gap:6px}.input-wrap input,.input-wrap select{width:100%;min-width:0;min-height:44px;border:1px solid var(--line-strong);padding:9px 10px;background:var(--surface);color:var(--ink)}.field-help{margin:4px 0 0;color:var(--muted);font-size:.78rem}.form-error{margin:12px 0 0;padding:8px 10px;border-left:4px solid var(--danger);background:var(--danger-soft);color:#762525}.form-error[hidden]{display:none}.form-actions{display:flex;flex-wrap:wrap;gap:8px;margin-top:17px}.button{min-height:42px;border:1px solid var(--accent);padding:8px 15px;cursor:pointer;font-weight:760}.button-primary{background:var(--accent);color:#fff}.button-secondary{background:var(--surface);color:var(--accent)}.result-box{margin-top:20px;padding:15px 16px;border:1px solid var(--accent);border-left-width:4px;background:var(--accent-soft)}.result-box[data-state=error]{border-color:var(--danger);background:var(--danger-soft)}.result-label{margin:0;color:var(--accent);font-size:.8rem;font-weight:780}.result-value{display:block;font-size:clamp(1.45rem,3.2vw,2.05rem);font-weight:780;overflow-wrap:anywhere}.result-status{margin:5px 0 0;font-size:.9rem}.result-details{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));margin:14px 0 0;border-top:1px solid #9db8ad;border-left:1px solid #9db8ad}.result-details[hidden]{display:none}.result-details div{padding:9px 10px;border-right:1px solid #9db8ad;border-bottom:1px solid #9db8ad}.result-details .detail-wide{grid-column:1/-1}.result-details dt{color:var(--muted);font-size:.76rem;font-weight:760}.result-details dd{margin:2px 0 0;font-size:.86rem;overflow-wrap:anywhere}.visual-heading-row{display:flex;justify-content:space-between;gap:14px}.status-badge{flex:none;padding:3px 8px;border:1px solid var(--line-strong);background:var(--paper);color:var(--muted);font-size:.75rem;font-weight:760}.status-badge[data-state=ready]{border-color:var(--accent);background:var(--accent-soft);color:var(--accent)}.visual-metrics{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));margin:15px 0 0;border-top:1px solid var(--line);border-left:1px solid var(--line)}.visual-metrics div{padding:9px 10px;border-right:1px solid var(--line);border-bottom:1px solid var(--line)}.visual-metrics dt{color:var(--muted);font-size:.75rem;font-weight:750}.visual-metrics dd{margin:2px 0 0;font-size:.85rem;font-weight:700;overflow-wrap:anywhere}.visual-stage{min-height:316px;display:grid;place-items:center;margin-top:15px;padding:24px 18px;overflow:hidden;border:1px solid var(--line-strong);background:linear-gradient(180deg,#fbfaf6,#edf2f2)}figure{width:100%;margin:0}.force-row{display:flex;align-items:center;justify-content:center;gap:12px;font-weight:800}.specimen{width:min(64%,360px);height:72px;border:2px solid var(--accent);background:#fff;overflow:hidden}.specimen span{display:block;width:8%;height:100%;background:repeating-linear-gradient(90deg,var(--accent-soft) 0 12px,#fff 12px 24px);transition:width .2s}.length-line{display:flex;justify-content:center;gap:12px;margin-top:22px;color:var(--muted);font-weight:700}figcaption,.visual-description,.scale-note{margin:9px 0 0;color:var(--muted);font-size:.8rem;text-align:center}.visual-description{text-align:left;font-size:.86rem}.scale-note{text-align:left;font-size:.75rem}.content-section{margin-top:42px}.formula-list{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));margin-top:16px;border-top:1px solid var(--line);border-left:1px solid var(--line)}.formula-list article{display:grid;gap:4px;padding:14px 15px;border-right:1px solid var(--line);border-bottom:1px solid var(--line)}.formula-list span{color:var(--muted);font-size:.82rem}.proof-guide{margin-top:20px;padding:17px 18px;border:1px solid var(--line);background:var(--surface)}.proof-guide ul{margin:10px 0 0;padding-left:1.25em}.site-footer{margin-top:38px;border-top:1px solid var(--line)}.footer-inner{display:flex;flex-wrap:wrap;gap:12px 18px;padding:20px 0 0;color:var(--muted);font-size:.8rem}.footer-inner a{color:var(--accent);font-weight:700}@media(max-width:760px){.tool-shell{grid-template-columns:1fr}.calculator-panel{border-right:0;border-bottom:1px solid var(--line)}}@media(max-width:460px){.calculator-panel,.visual-panel{padding:18px 14px}.mode-options{grid-template-columns:1fr}.input-wrap,.result-details,.visual-metrics,.formula-list{grid-template-columns:1fr}.result-details .detail-wide{grid-column:auto}.visual-stage{min-height:270px;padding:18px 10px}.force-row{gap:6px;font-size:.82rem}.specimen{height:58px}}
