/***** 约束默认样式 *****/
html, body, form {
    border: 0;
    margin: 0;
    padding: 0;
}

h1, h2, h3, h4, h5, h6 {
    margin: 0;
    padding: 0;
    font-weight: normal;
}

p, ul, ol, ul li {
    margin: 0;
    padding: 0;
}

ul, ol {
    list-style: none;
}


img {
    border: 0;
}