Google HTML/CSS Style Guide – Omit Optional Tags
Interestingly they don&#x27;t seem to have a rule against one line declarations.<p>I alwats use this style, which imho is very handy, because of the tree structure <i>and</i> admittedly because I have a super cool macro in Vim that copies the characters from the line above, word by word so create rules that afect children of the rule above it requires just a few keystrokes:<p><pre><code>  #some-div { margin:1em 0; }
  #some-div .inner { padding:5px 10px; }
  #some-div .inner p { font-size:90%; }
</code></pre>
This makes the structure of the declarations more obvious imho, and I tend to have a nicely organized series of structures like that that are logically grouped together.<p>Obviously this applies more to components&#x2F;widgets than the basic rules and layout.<p>If a declaration is long then I use newlines.. but even then I tend to group things together eg.<p><pre><code>  #some-div {
    display:inline; margin: ...; padding: ...;
    border-radius: ...; border-color: ...; 
    font-size:90%; text-align:center;
  }
</code></pre>
Basically within a css rule I&#x27;ll group together the layout properties, the text properties, etc.