types/src/main/java/com/google/common/html/types/SafeStyleBuilder.java
private static String checkConstantValue(@CompileTimeConstant final String value) {
    for (int i = 0; i < value.length(); i++) {
      char c = value.charAt(i);
      if (c == '<' || c == '>' || c == '"' || c == '\'' || c == ';') {
        throw new IllegalArgumentException(
            "Value contains HTML/CSS meta-characters ([<>\"';]): " + value);
      } else if (
            value.startsWith("/*", i) || value.startsWith("*/", i) || value.startsWith("//", i)) {
          throw new IllegalArgumentException(
              "Value contains CSS comment marker (/*, */ or //): " + value);
      }
    }
    return value;
  }
private static String checkConstantValue(@CompileTimeConstant final String value) {
    for (int i = 0; i < value.length(); i++) {
      char c = value.charAt(i);
      if (c == '<' || c == '>' || c == '"' || c == '\'' || c == ';') {
        throw new IllegalArgumentException(
            "Value contains HTML/CSS meta-characters ([<>\"';]): " + value);
      } else if (
            value.startsWith("/*", i) || value.startsWith("*/", i) || value.startsWith("//", i)) {
          throw new IllegalArgumentException(
              "Value contains CSS comment marker (/*, */ or //): " + value);
      }
    }
    return value;
  }
Throws IllegalArgumentException if {@code value} contains any of a few blacklisted characters
which would change the syntactic structure of the CSS or entirely break out of the HTML style
attribute.