CSL for Zotero Citations

I am attempting to formulate my bibliography in Zotero to meet the requirements of my faculty's library. It is a Vancouver style with the following format:

Citation: (number)

Reference Authors (Surname, Initial). Title. Abbreviated journal name. numeric year;Volume number(issue number):pages [Accessed: numeric day.month.year] DOI or URL.

I am having difficulty with producing the year issued and having the date accessed be in the day.month.year format.

I am also unable to have the URL display only if the DOI is not present.

I tried to add the following:

<date variable=”issued”>
 <date-part name="day"/>
 <date-part name="month" form="numeric" strip-periods="true"/> 
 <date-part name="year"/>

with the plan of adding accessed but I keep returning an error

Thank you for any help.

Solution

For year issued:

<date variable="issued" form="numeric" date-part="year"/>

For date accessed, your code snippet has two issues: you're using curly quotes and you're missing the final tag. Corrected you'd have

<date variable="accessed">
 <date-part name="day" suffix="."/>
 <date-part name="month" form="numeric" suffix="."/> 
 <date-part name="year"/>
</date>

Finally, for the DOI/URL logic, you'd want something like

<choose>
  <if variable="DOI">
    <text variable="DOI" prefix="https://doi.org/"/>
  </if>
  <else if variable="URL">
    <group delimiter=": " prefix="[" suffix="]">
      <text term="accessed" text-case="capitalize-first"/>
      <date variable="accessed">
        <date-part name="day" suffix="."/>
        <date-part name="month" form="numeric" suffix="."/> 
        <date-part name="year"/>
      </date>
    </group>
    <text variable="URL" prefix=" "/>
  </else-if>
</choose>

(FWIW, you're likely to get help faster for CSL on the Zotero forums)