:root{color-scheme:light;--ink:#183c37;--muted:#596d67;--green:#17604e;--line:#dbe3d9;--paper:#f6f7f1}*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font-family:system-ui,-apple-system,"PingFang TC","Microsoft JhengHei",sans-serif;line-height:1.7}a{color:inherit}button,input{font:inherit}button,a,input,summary{-webkit-tap-highlight-color:transparent}button,summary{cursor:pointer}button:focus-visible,a:focus-visible,input:focus-visible,summary:focus-visible,[tabindex]:focus-visible{outline:3px solid #b47a16;outline-offset:4px}.site-header{max-width:1200px;margin:auto;padding:25px 32px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line);gap:20px}.brand{font-size:36px;display:flex;gap:12px;align-items:center;text-decoration:none}.brand span{font-size:16px;font-weight:700;line-height:1.4}.brand small{display:block;font-size:9px;letter-spacing:2px;font-weight:500;margin-top:4px}nav{display:flex;gap:24px;font-size:14px}nav a{text-decoration:none;padding:10px 0}.active{border-bottom:2px solid var(--green)}main{max-width:1136px;margin:auto;padding:0 24px}.hero{padding:64px 0 40px;text-align:center}.eyebrow,.section-kicker{font-size:12px;font-weight:650;letter-spacing:2px;color:var(--green);margin:0 0 12px}h1{font-size:clamp(38px,5vw,62px);letter-spacing:-2px;line-height:1.22;margin:20px 0;font-weight:650}h2{font-size:25px;letter-spacing:-.5px;line-height:1.4;margin:0 0 18px}.lead{font-size:21px;margin:24px 0 8px}.intro{color:var(--muted);margin:0}.hero-formula{font-size:24px;margin:28px auto 14px}.legend{font-size:13px;color:var(--muted)}.workspace{display:grid;grid-template-columns:1.3fr 1fr;gap:24px;margin:12px 0 38px}.panel{border:1px solid var(--line);border-radius:20px;background:#fff;padding:30px;min-width:0}.fields{display:grid;grid-template-columns:1fr 1fr;gap:20px;margin-top:25px}label{font-size:15px;font-weight:650}label span{display:block;font-size:12px;color:var(--muted);font-weight:400;margin:3px 0 12px}input{width:100%;min-height:56px;border:1px solid #a7bab2;border-radius:9px;background:#fbfcf8;padding:10px 14px;font-size:23px;color:var(--ink)}input[aria-invalid=true]{border-color:#ad3328}.muted{font-size:13px;color:var(--muted)}.primary{display:flex;justify-content:space-between;align-items:center;width:100%;border:0;border-radius:9px;background:var(--green);color:white;padding:13px 20px;min-height:50px;text-decoration:none;font-weight:600}.primary:hover{background:#114737}.method{background:#eaf0e5}.method h2{margin-top:20px}.method p{font-size:14px;color:#4f665b}.pill{display:inline-block;font-size:11px;border:1px solid #c2d3bd;padding:4px 10px;border-radius:30px}.method-footer{padding-top:18px;border-top:1px solid #cbd7c4;font-size:27px;display:flex;align-items:center;gap:10px}.method-footer span{font-size:12px}.method-footer .divider{font-size:22px;color:#a9bba2;margin:0 8px}#error{color:#9e2b23;font-size:14px}.section-heading{display:flex;justify-content:space-between;align-items:center;gap:20px;margin-top:40px}.actions{display:flex;gap:8px;flex-shrink:0}.actions button{background:transparent;border:1px solid #b9c8bd;padding:10px 14px;border-radius:8px;min-height:44px;color:var(--ink);font-size:13px}.actions button:hover{background:#e8eee2}.formula{overflow-x:auto;overflow-y:hidden;max-width:100%;padding:8px 4px;text-align:center}.katex-display{margin:.4em 0;width:max-content;min-width:100%}.katex-display>.katex{white-space:nowrap}details{background:white;border:1px solid var(--line);border-radius:14px;margin:12px 0;overflow:hidden}summary{padding:20px 24px;min-height:64px;display:flex;align-items:center;gap:14px;list-style:none}summary::-webkit-details-marker{display:none}.step-number{font-size:12px;color:var(--green);background:#edf2e8;border-radius:7px;padding:5px 9px}.step-title{font-weight:650}.step-value{font-size:14px;color:var(--muted);margin-left:auto;font-variant-numeric:tabular-nums;overflow-wrap:anywhere}summary::after{content:'＋';font-size:20px}details[open] summary::after{content:'−'}details[open] summary{border-bottom:1px solid var(--line)}.derivation{padding:16px 24px 22px}.operation{display:grid;grid-template-columns:112px minmax(0,1fr);align-items:center;padding:7px 0}.operation-label{font-size:12px;color:var(--muted)}.operation:last-child{background:#f1f5eb;border-radius:8px}.data-grid{display:grid;grid-template-columns:1fr 1fr;gap:24px;margin:40px 0}.table-scroll{overflow-x:auto;max-width:100%}table{width:100%;border-collapse:collapse;font-size:13px;font-variant-numeric:tabular-nums;white-space:nowrap;text-align:right}th,td{padding:12px 10px;border-bottom:1px solid #e9ede5}th{color:var(--muted);font-weight:500;font-size:12px}th:first-child,td:first-child{text-align:left}tbody tr:last-child{background:#edf3e8;font-weight:650}#chart svg{width:100%;height:auto;display:block;margin-top:24px}.answer{padding:40px 24px;background:#193f35;border-radius:20px;color:#fff;text-align:center;margin-bottom:52px}.answer .section-kicker{color:#bbd4a5}.answer .formula{font-size:clamp(20px,3vw,30px)}.answer p:last-child{color:#d6e4ce;font-size:14px}.answer h2{font-size:18px}footer{max-width:1136px;margin:auto;border-top:1px solid var(--line);padding:24px;display:flex;justify-content:space-between;gap:15px;font-size:12px;color:var(--muted)}.tool-card{max-width:660px;margin:0 auto 70px}.tool-card .primary{margin-top:24px}.sr-only,.skip:not(:focus){position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.skip:focus{display:block;padding:16px}[hidden]{display:none!important}@media(max-width:760px){.site-header{padding:18px 20px}nav{gap:14px;font-size:12px}main{padding:0 16px}.hero{padding:38px 0 24px}.hero-formula{font-size:19px}.desktop{display:none}.workspace,.data-grid{grid-template-columns:1fr;gap:16px}.panel{padding:22px}.fields{gap:14px;grid-template-columns:1fr}.method-footer{padding-top:12px}.section-heading{align-items:flex-start;flex-direction:column;gap:0}.actions{margin:0 0 14px}summary{padding:16px 14px;gap:9px}.step-title{font-size:14px}.step-value{font-size:12px}.derivation{padding:12px}.operation{grid-template-columns:minmax(0,1fr);padding:10px 0}.operation-label{padding-left:6px}.formula{font-size:16px}.answer .formula{font-size:20px}footer{flex-direction:column;gap:4px}}@media(max-width:380px){.fields{grid-template-columns:1fr}.brand span{font-size:13px}.brand small{font-size:8px;letter-spacing:1px}nav{gap:10px}.step-value{max-width:120px}}

/* Motion is decorative; results remain complete and accessible immediately. */
html{scroll-behavior:smooth}#result-summary,#steps-title,#calculator{scroll-margin-top:24px}
#reload-page{border:1px solid var(--line);border-radius:8px;background:transparent;color:var(--ink);padding:8px 12px;min-height:44px;font-size:13px}
#reload-page:hover{background:#e8eee2}.primary{transition:background .2s,transform .2s,box-shadow .2s}.primary:hover{transform:translateY(-2px);box-shadow:0 6px 16px #17604e24}.primary:active{transform:scale(.98)}
.answer{margin-top:24px;margin-bottom:30px}.result-links{display:flex;justify-content:center;flex-wrap:wrap;gap:12px;margin-top:24px}.result-links a,.result-links button{display:inline-flex;align-items:center;justify-content:center;min-height:44px;padding:10px 16px;border:1px solid #75968a;border-radius:8px;background:transparent;color:white;font-size:14px;text-decoration:none}.result-links a:hover,.result-links button:hover{background:#ffffff16}
@keyframes arrive{from{opacity:.25;transform:translateY(18px)}to{opacity:1;transform:translateY(0)}}
@keyframes resultPulse{from{box-shadow:0 0 0 8px #a9c58d66}to{box-shadow:0 0 0 0 #a9c58d00}}
@keyframes trace{from{stroke-dashoffset:1}to{stroke-dashoffset:0}}
.result-arrived{animation:arrive .45s ease-out,resultPulse .9s ease-out}.revealed{animation:arrive .5s ease-out}details[open] .derivation{animation:arrive .25s ease-out}.chart-panel.revealed polyline{stroke-dasharray:1;animation:trace 1.1s ease-out both}
@media(max-width:760px){.site-header{flex-wrap:wrap}.site-header nav{width:100%;justify-content:space-between;align-items:center}.result-links{flex-direction:column}.result-links a,.result-links button{width:100%}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*::before,*::after{animation:none!important;transition:none!important}.chart-panel.revealed polyline{stroke-dasharray:none}}