:root{--bg:#f6f8fb;--surface:#fff;--text:#0f1a33;--muted:#5d6b82;--line:#dbe3ee;--strong:#c6d1df;--primary:#1766d1;--primary-dark:#0e4ea8;--primary-soft:#eaf3ff;--warning:#f59e0b;--warning-soft:#fff5df;--footer:#06152b;--footer-text:#f3f7ff;--footer-muted:#c8d6ea;--shadow:0 12px 30px rgba(15,26,51,.08);--radius:14px;--radius-sm:10px;--container:1120px;font-family:Roboto,Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",Arial,sans-serif}*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;color:var(--text);background:radial-gradient(circle at 20% 0%,rgba(23,102,209,.08),transparent 32rem),linear-gradient(180deg,#fbfdff 0%,var(--bg) 44%,#fff 100%);font-family:inherit;line-height:1.45}a{color:var(--primary);text-decoration:none;font-weight:800}a:hover{color:var(--primary-dark)}button,input,select{font:inherit}.site-header{position:sticky;top:0;z-index:10;background:rgba(255,255,255,.94);backdrop-filter:blur(16px);border-bottom:1px solid var(--line)}.header-inner{max-width:var(--container);min-height:72px;margin:0 auto;padding:0 24px;display:flex;align-items:center;justify-content:space-between;gap:20px}.brand{display:inline-flex;flex-direction:column;color:var(--text);line-height:1;letter-spacing:-.04em}.brand strong{font-size:1.35rem;font-weight:900}.brand strong span{color:var(--primary)}.brand small{margin-top:4px;color:var(--muted);letter-spacing:.08em;font-size:.62rem;font-weight:900;text-transform:uppercase}.nav{display:flex;gap:22px;font-size:.92rem}.nav a{color:var(--text);font-weight:900}.nav a:hover,.nav a[aria-current=page]{color:var(--primary)}.menu-button{display:none;border:0;background:transparent;font-size:1.25rem;cursor:pointer;color:var(--text)}.mobile-nav{display:none;border-top:1px solid var(--line);background:#fff;padding:10px 24px 18px}.mobile-nav.open{display:block}.mobile-nav a{display:block;padding:10px 0;color:var(--text)}.container{max-width:var(--container);margin:0 auto;padding:26px 24px 0}.breadcrumb{display:flex;gap:8px;flex-wrap:wrap;margin:2px 0 24px;color:var(--muted);font-size:.84rem}.breadcrumb a{color:var(--muted);font-weight:700}.breadcrumb span:last-child{color:var(--text)}.eyebrow{color:var(--primary);font-weight:900;letter-spacing:.08em;text-transform:uppercase;font-size:.72rem;margin:0 0 8px}h1,h2,h3{letter-spacing:-.045em;line-height:1.08;margin:0}h1{font-size:clamp(2rem,4vw,3.2rem);max-width:920px}h2{font-size:clamp(1.45rem,2.4vw,2rem);margin-bottom:14px}h3{font-size:1.15rem;margin-bottom:10px}.lede{color:var(--muted);max-width:790px;margin:12px 0 0;font-size:1.05rem}.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow)}.tool-card{padding:24px;margin-top:20px}.section{margin:28px 0}.grid-2{display:grid;grid-template-columns:1fr 360px;gap:24px;align-items:start}.grid-2>*,.grid-3>*,.converter-grid>*{min-width:0}.grid-3{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}.field-stack,.calc-form,.side-stack,.faq{display:grid;gap:12px}.converter-grid{display:grid;grid-template-columns:1fr 58px 1fr;gap:28px;align-items:center}.label{display:block;color:var(--muted);text-transform:uppercase;font-size:.78rem;font-weight:900;letter-spacing:.06em;margin-bottom:6px}.select,.input{width:100%;border:1px solid var(--strong);background:#fff;color:var(--text);border-radius:var(--radius-sm);padding:12px 14px;min-height:48px;outline:none;font-weight:800}.input.big{font-size:2.1rem;font-weight:900;letter-spacing:-.04em}.input:focus,.select:focus{border-color:var(--primary);box-shadow:0 0 0 4px rgba(23,102,209,.12)}.input[aria-invalid=true]{border-color:#c2410c;box-shadow:0 0 0 4px rgba(194,65,12,.12)}.helper,.muted{color:var(--muted)}.helper{font-size:.84rem;margin-top:-4px}.error-text{display:none;color:#c2410c;font-weight:800;font-size:.86rem}.error-text.show{display:block}.swap-button{width:54px;height:54px;display:grid;place-items:center;border-radius:50%;border:1px solid var(--line);background:#fff;box-shadow:0 8px 22px rgba(15,26,51,.08);cursor:pointer;font-size:1.3rem}.result-panel{min-height:70px;padding:12px 16px;border:1px solid var(--strong);background:linear-gradient(180deg,#f4f8ff,#fff);border-radius:var(--radius-sm);display:grid;place-items:center;text-align:center}.result-value{color:var(--primary);font-size:2.35rem;letter-spacing:-.05em;font-weight:900;line-height:1}.result-unit{color:var(--primary);font-size:1rem;margin-left:4px}.result-sub{color:var(--muted);font-size:.86rem;margin-top:8px}.basis-line{display:flex;justify-content:center;gap:9px;flex-wrap:wrap;margin-top:10px;color:var(--muted);font-size:.84rem}.notice,.warning{margin-top:16px;padding:13px 16px;border-radius:var(--radius-sm);display:flex;gap:12px;align-items:center;font-size:.92rem}.notice{border:1px solid #cfe2ff;background:var(--primary-soft)}.warning{border:1px solid #f8d793;background:var(--warning-soft)}.notice .icon,.warning .icon{flex:0 0 auto;width:32px;height:32px;border-radius:50%;display:grid;place-items:center;background:var(--primary);color:#fff;font-weight:900}.warning .icon{background:var(--warning)}.notice a{margin-left:auto;white-space:nowrap;font-size:.9rem}.slot-preview{border:2px dashed #7f95b0;color:#405873;border-radius:var(--radius-sm);min-height:96px;display:grid;place-items:center;text-align:center;font-size:.78rem;letter-spacing:.04em;text-transform:uppercase;margin:20px 0;background:repeating-linear-gradient(135deg,#fff,#fff 10px,#f1f6fc 10px,#f1f6fc 20px)}.slot-preview strong{display:block;color:var(--text);font-size:.95rem;letter-spacing:0;text-transform:none;margin-top:3px}.slot-preview small{display:block;color:var(--muted);letter-spacing:0;text-transform:none;margin-top:2px}.table-card{overflow:hidden;border-radius:var(--radius);border:1px solid var(--line);background:#fff}.table-scroll{overflow-x:auto;-webkit-overflow-scrolling:touch}table{width:100%;border-collapse:collapse;min-width:620px;font-size:.92rem}th,td{border-bottom:1px solid var(--line);padding:11px 12px;text-align:left;vertical-align:middle}th{background:#fbfdff;font-size:.82rem;font-weight:900}td{color:#1a2740}tr.highlight td{background:#edf5ff;color:#0c55b0;font-weight:900}.content-card{padding:22px}.content-card p,.legal-body p{color:#2d3b52}.formula-box{padding:16px;border:1px solid var(--line);background:#f8fbff;border-radius:var(--radius-sm);font-weight:900;overflow-x:auto}.result-large{background:linear-gradient(180deg,#f4f8ff,#fff);border:1px solid var(--line);border-radius:var(--radius);padding:24px;text-align:center;margin-top:18px}.result-large .big-number{color:var(--primary);font-size:2.45rem;font-weight:900;letter-spacing:-.05em}.result-large .caption{color:var(--muted);margin-top:6px}.tool-list,.check-list{list-style:none;padding:0;margin:0;display:grid;gap:8px}.tool-list a{display:flex;justify-content:space-between;align-items:center;gap:12px;padding:12px;border:1px solid var(--line);border-radius:var(--radius-sm);color:var(--text);background:#fff}.tool-list small{display:block;color:var(--muted);font-weight:500;margin-top:2px}.check-list li{padding:11px 12px;border:1px solid var(--line);border-radius:var(--radius-sm);background:#fff}details{border:1px solid var(--line);border-radius:var(--radius-sm);background:#fff;overflow:hidden}summary{cursor:pointer;font-weight:900;padding:14px 16px;list-style:none}summary::-webkit-details-marker{display:none}details p{margin:0;padding:0 16px 16px;color:#314059}.tabs{display:flex;border-bottom:1px solid var(--line);gap:6px;margin-bottom:18px;overflow-x:auto}.tab{border:0;background:transparent;color:var(--muted);font-weight:900;padding:12px 14px;cursor:pointer;border-bottom:3px solid transparent;white-space:nowrap}.tab[aria-selected=true]{color:var(--primary);border-color:var(--primary)}.size-comparison{display:grid;grid-template-columns:repeat(3,1fr);gap:18px;align-items:end;padding:14px}.paper-shape{border:2px solid #9ec3f7;background:linear-gradient(180deg,#fbfdff,#f2f7ff);border-radius:4px;display:grid;place-items:center;color:var(--primary);font-weight:900;margin:0 auto 8px}.paper-a4{width:76px;height:108px}.paper-letter{width:84px;height:110px}.paper-legal{width:84px;height:136px}.center{text-align:center}.legal-body{max-width:820px}.legal-body h2{margin-top:30px}.footer{margin-top:42px;background:var(--footer);color:var(--footer-text)}.footer-inner{max-width:var(--container);margin:0 auto;padding:24px;display:grid;grid-template-columns:1.2fr repeat(4,1fr);gap:22px}.footer .brand{color:#fff}.footer .brand small{color:var(--footer-muted)}.footer h4{margin:0 0 10px;color:#fff;font-size:.9rem}.footer a{display:block;color:var(--footer-text);font-weight:700;margin:6px 0;font-size:.88rem}.footer a:hover{color:#fff;text-decoration:underline}.footer .muted{color:var(--footer-muted)}.copyright{max-width:var(--container);margin:0 auto;padding:0 24px 18px;color:var(--footer-muted);font-size:.82rem}@media(max-width:900px){.nav{display:none}.menu-button{display:block}.container{padding:18px 16px 0}.header-inner{padding:0 16px}.brand strong{font-size:1.05rem}.brand small{font-size:.52rem}.breadcrumb{display:none}.tool-card{padding:16px}.converter-grid,.grid-2,.grid-3{grid-template-columns:1fr}.converter-grid{gap:14px}.swap-button{margin:0 auto;transform:rotate(90deg)}.notice,.warning{align-items:flex-start}.notice a{margin-left:0}table{min-width:540px;font-size:.86rem}.slot-preview{min-height:100px;margin:18px 0}.footer-inner{grid-template-columns:1fr 1fr}.footer-inner>div:first-child{grid-column:1/-1}}@media(max-width:520px){h1{font-size:1.58rem}h2{font-size:1.25rem}.lede{font-size:.94rem}.input.big{font-size:1.6rem}.result-value{font-size:2rem}.notice,.warning{font-size:.82rem;padding:12px}.notice .icon,.warning .icon{width:28px;height:28px}.footer-inner{grid-template-columns:1fr}.size-comparison{grid-template-columns:1fr;gap:12px}table{min-width:500px}}