题解 | #定位 - fixed#

{"css":"","js":"","html":"\n\n \n \n <style type="text/css">\n * {\n margin: 0;\n padding: 0;\n }\n nav {\n position: fixed;\n top: 0;\n width: 100px;\n background: green;\n \n }\n section {\n margin-top: 1rem;\n }\n \n \n \n \t