Hi
1. create a file custom_light.css into themes/default/css/_light and try something like this :
@media screen and (max-width:50em) {
.poster .listlevel1 {
float: right;
}
}
You should not edit index.css, but you should add all your custom edits to custom_light.css
2. Try to play with the settings inside Admin > Configuration > Search Engine Optimisation > Base Settings
Enable Display the topic first message snippet as the meta-tag description