css 来自https://www.mapbox.com/tilemill/docs/crashcourse/styling/

Posted 2021-05-13

 #earthquakes {
   [Magnitude >= 2.5] { marker-width:6; }
   [Magnitude >= 3]   { marker-width:8; }
   [Magnitude >= 3.5] { marker-width:10; }
   [Magnitude >= 4]   { marker-width:12; }
   [Magnitude >= 4.5] { marker-width:14; }
   [Magnitude >= 5]   { marker-width:16; }
   [Magnitude >= 5.5] { marker-width:18; }
   [Magnitude >= 6]   { marker-width:20; }
 }