:root{--ink:#183936;--muted:#667e79;--green:#137969;--line:#dbe5df;--paper:#f5f7f2;--white:#fff;--soft:#e6f1eb}*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--paper);color:var(--ink);font:16px/1.65 system-ui,-apple-system,"Segoe UI","Microsoft YaHei",sans-serif}a{color:var(--green);text-decoration:none}a:hover{text-decoration:underline}button,input{font:inherit}button{cursor:pointer}a,button,input,summary{outline-offset:4px}a:focus-visible,button:focus-visible,input:focus-visible,summary:focus-visible{outline:3px solid #d28b29}.container{max-width:1120px;margin:auto;padding:0 28px}.header{background:rgba(255,255,255,.95);border-bottom:1px solid var(--line)}.nav{max-width:1120px;margin:auto;min-height:84px;padding:16px 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.wrong-option{background:#fff0e9;border-color:#b84b38}.wrong-option .answer-tag{color:#963c27}
.knowledge.section-heading{flex-wrap:wrap}.knowledge.section-heading>div{flex:1;min-width:220px}
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.nav nav{flex-wrap:wrap}