:root{--ink:#20252b;--muted:#59636d;--accent:#344d68;--line:#e1e4e8;--soft:#f5f6f7}*{box-sizing:border-box}body{margin:0;color:var(--ink);background:#fff;font:16px/1.65 Arial,"Microsoft YaHei",sans-serif}main{max-width:1040px;margin:auto;padding:28px}h1{font-size:24px;margin:0;line-height:1.3}p{margin:8px 0;color:var(--muted)}.eyebrow{font:13px/1.5 monospace;letter-spacing:1px;color:var(--accent)}.heading{display:flex;align-items:center;justify-content:space-between;gap:12px}button,input,select{font:inherit;color:inherit;border:1px solid var(--line);border-radius:3px;background:#fff;padding:10px 12px;min-width:0}button{cursor:pointer}button:hover{border-color:var(--accent)}button:focus-visible,input:focus-visible,select:focus-visible,a:focus-visible{outline:2px solid var(--accent);outline-offset:3px}label{display:flex;flex-direction:column;gap:6px;font-size:14px}select,input{width:100%}.converter{margin:24px 0;border-top:1px solid var(--line);padding-top:20px}.converter>label{max-width:280px}.conversion-row{display:grid;grid-template-columns:2fr 1fr auto 1fr;gap:14px;align-items:end;margin-top:20px}.note{font-size:14px}.result{margin-top:20px;padding:20px;background:var(--soft);border:1px solid var(--line);min-height:155px}output{font-size:28px;font-weight:600;overflow-wrap:anywhere}#equation{font:13px/1.7 monospace;overflow-wrap:anywhere}#error{color:#9b3434}footer{font-size:14px}footer a{color:var(--accent)}@media(max-width:620px){main{padding:20px 16px}.conversion-row{grid-template-columns:1fr 1fr}.conversion-row label:first-child{grid-column:1/-1}#swap{grid-column:1/-1;grid-row:3}h1{font-size:20px}output{font-size:24px}.heading button{white-space:nowrap}}