    requirementDiagram

    % a bad comment, because mermaid...
    %% a comment

    requirement test_req:::important {
        id: 123
        text: "class styling example"
        risk: low
        %% error on "lo"
        risk: lo
        verifymethod: test
        VerifyMethoD: TesT
    }
    testreq:::important

    element "__a__c__*abx*__a__c__<b>abc&lt;abc#abc;&abc#abc\*x\_ y" {
        docref: bla bla
        docref: + oups
        docref: é oups
        docref: but ok for é...
        % error: unknown doref + < + >
        doref: __a__c__*abx*__a__c__<b>abc&lt;abc#abc;&abc#abc\*x\_ y
    }

    element __a__c__*abx*__a__c__<b>abc&lt;abc#abc;&abc#abc\*x\_ y {
        type: direction functionalRequirementrequirementDiagra0dsd ds s++%% simulation %% ds element
        %% error on "id"
        type: Id is a keyword
    }
    a:::  im portant

    test_entity <- satisfies - "test_req"
    "test_entity" - satisfies -> test_req
    &lt;entity - unknown -> &lt;entity"x

    classDef important font-weight:bold
    classDef "important" font-weight:bold
    classDef important , "a" font-weight:bold
    classDef "important" , a*b*c font-weight:bold

    class entity important , a*b*c
    class "testa entity" important , "a"
    class entity , "a" "important" , a*b*c
    class "testa entity" , a*b*c "important" , "a"

    style entity fill:#93f,stroke:#333
    style "testa entity" fill:#93f,stroke:#333
    style entity , "a" fill:#93f,stroke:#333
    style "testa entity" , a*b*c fill:#93f,stroke:#333