:root{--bg:#f7fafc;--surface:#ffffff;--text:#1a2b33;--text-muted:#52707c;--accent:#0e7490;--accent-dark:#155e75;--accent-light:#ecfeff;--border:#d9e5ea;--radius:10px;--shadow:0 1px 3px rgba(16,42,53,0.08),0 4px 14px rgba(16,42,53,0.05)}*{box-sizing:border-box;margin:0;padding:0}html{scroll-behavior:smooth}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica,Arial,sans-serif;background:var(--bg);color:var(--text);line-height:1.65;font-size:17px}a{color:var(--accent);text-decoration:none}a:hover{text-decoration:underline}.container{max-width:820px}.container,.container-wide{margin:0 auto;padding:0 20px}.container-wide{max-width:1080px}.site-header{background:var(--surface);border-bottom:1px solid var(--border);position:-webkit-sticky;position:sticky;top:0;z-index:50}.site-header-inner{max-width:1080px;margin:0 auto;padding:14px 20px;justify-content:space-between;gap:16px;flex-wrap:wrap}.site-header-inner,.site-logo{display:flex;align-items:center}.site-logo{font-weight:700;font-size:1.15rem;color:var(--text);gap:8px}.site-logo:hover{text-decoration:none}.site-nav{display:flex;gap:18px;flex-wrap:wrap;font-size:.92rem}.site-nav a{color:var(--text-muted)}.site-nav a:hover{color:var(--accent)}.hero{text-align:center;padding:56px 20px 40px}.hero h1{font-size:clamp(1.7rem,4.5vw,2.5rem);line-height:1.2;margin-bottom:14px}.hero p{color:var(--text-muted);max-width:620px;margin:0 auto;font-size:1.08rem}.tool-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));grid-gap:18px;gap:18px;padding:10px 0 50px}.tool-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:22px;box-shadow:var(--shadow);display:block;color:var(--text);transition:transform .12s ease,border-color .12s ease}.tool-card:hover{transform:translateY(-2px);border-color:var(--accent);text-decoration:none}.tool-card h2,.tool-card h3{font-size:1.08rem;margin-bottom:6px;color:var(--accent-dark)}.tool-card p{font-size:.92rem;color:var(--text-muted)}.calc-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:26px;box-shadow:var(--shadow);margin:26px 0 34px}.calc-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(210px,1fr));grid-gap:16px;gap:16px}.field{display:flex;flex-direction:column;gap:5px}.field label{font-size:.86rem;font-weight:600;color:var(--text-muted)}.field input,.field select{padding:10px 12px;border:1px solid var(--border);border-radius:8px;font-size:1rem;background:#fff;color:var(--text);width:100%}.field input:focus,.field select:focus{outline:2px solid var(--accent);outline-offset:1px;border-color:var(--accent)}.calc-result{margin-top:22px;background:var(--accent-light);border:1px solid #a5f3fc;border-radius:var(--radius);padding:18px 20px}.calc-result-value{font-size:1.7rem;font-weight:700;color:var(--accent-dark)}.calc-result-label{font-size:.9rem;color:var(--text-muted)}.calc-note{margin-top:14px;font-size:.82rem;color:var(--text-muted)}.result-table{width:100%;border-collapse:collapse;margin-top:14px;font-size:.95rem}.result-table td,.result-table th{text-align:left;padding:9px 12px;border-bottom:1px solid var(--border)}.result-table th{font-size:.82rem;text-transform:uppercase;letter-spacing:.04em;color:var(--text-muted)}.result-table .best{background:var(--accent-light);font-weight:600}.table-scroll{overflow-x:auto}.article{padding-bottom:40px}.article h1{font-size:clamp(1.55rem,4vw,2.1rem);line-height:1.25;margin:34px 0 10px}.article .lede{color:var(--text-muted);font-size:1.06rem;margin-bottom:6px}.article h2{font-size:1.35rem;margin:34px 0 12px}.article h3{font-size:1.1rem;margin:24px 0 8px}.article p{margin:12px 0}.article ol,.article ul{margin:12px 0 12px 24px}.article li{margin:6px 0}.article code{background:#eef4f7;border-radius:5px;padding:2px 6px;font-size:.9em}.formula{background:#eef4f7;border-left:3px solid var(--accent);border-radius:6px;padding:12px 16px;margin:14px 0;font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:.92rem;overflow-x:auto}.disclaimer{background:#fffbeb;border:1px solid #fde68a;border-radius:var(--radius);padding:14px 18px;font-size:.88rem;color:#713f12;margin:22px 0}.faq-item{border-bottom:1px solid var(--border);padding:16px 0}.faq-item h3{font-size:1.02rem;margin:0 0 6px}.faq-item p{margin:0;color:var(--text-muted);font-size:.96rem}.related{margin:40px 0}.related h2{font-size:1.2rem;margin-bottom:14px}.site-footer{border-top:1px solid var(--border);background:var(--surface);margin-top:40px;padding:34px 0;font-size:.88rem;color:var(--text-muted)}.footer-grid{max-width:1080px;margin:0 auto;padding:0 20px;display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));grid-gap:24px;gap:24px}.footer-grid h4{font-size:.82rem;text-transform:uppercase;letter-spacing:.05em;margin-bottom:10px;color:var(--text)}.footer-grid ul{list-style:none}.footer-grid li{margin:6px 0}.footer-grid a{color:var(--text-muted)}.footer-grid a:hover{color:var(--accent)}.footer-bottom{max-width:1080px;margin:26px auto 0;padding:18px 20px 0;border-top:1px solid var(--border)}.breadcrumbs{font-size:.85rem;padding-top:22px}.breadcrumbs,.breadcrumbs a{color:var(--text-muted)}@media (max-width:560px){body{font-size:16px}.calc-card{padding:18px}}