Rearrange CF home page into two columns using HTML

assets/css/custom.css

@@ -105,4 +105,8 @@ border-color: #e0e0e0;
 
 .btn-hero:hover {
 background-color: #e2e6ea;
-}
+}
+
+figcaption {
+  font-style: italic;
+}

index.md

@@ -13,77 +13,88 @@ hero_button_url: Data/cf-conventions/cf-conventions-1.13/cf-conventions.html # O
 
 <br>
 
-The CF metadata conventions are designed to promote the processing and sharing of files created with the [NetCDF API][api].
+The CF metadata conventions are designed to promote the processing and sharing of files created with the [NetCDF API](https://www.unidata.ucar.edu/software/netcdf).
 The conventions define metadata that provide a definitive description of what the data in each variable represents, and the spatial and temporal properties of the data.
 This enables users of data from different sources to decide which quantities are comparable, and facilitates building applications with powerful extraction, regridding, and display capabilities.
 The CF convention includes a standard name table, which defines strings that identify physical quantities.
 
 Initially CF was developed for gridded data from climate and forecast models (hence "CF") of the atmosphere and ocean, but its use has subsequently extended to other geosciences, and to observations as well as numerical models.
 The use of CF is recommended where applicable by Unidata.
 
----
+<!-- The classes in the <div>s are used to produce two columns. They respond
+to the width of the browser window.  Within each row-class <div>, the number of
+columns N in the col-md-N-class <div>s should add up to 12, and the window is
+divided into columns according to the proportions of the Ns. The attribute
+markdown="1" signals that the text within the div is markdown, not HTML. -->
+
+<div class="row">
+<div class="col-md-6" markdown="1">
+
+### Working draft
 
-#### [Ask a question &#x2753; about how to use CF][github_askq]
+[HTML](/cf-conventions/cf-conventions.html)
+[PDF](/cf-conventions/cf-conventions.pdf)
 
 ### Latest release (1.13)
-[HTML][releasedhtml] [PDF][releasedpdf]  
 
-### Working draft  
-[HTML][workinghtml] [PDF][workingpdf]
+[HTML](Data/cf-conventions/cf-conventions-1.13/cf-conventions.html) 
+[PDF](Data/cf-conventions/cf-conventions-1.13/cf-conventions.pdf) 
 
-### Check the latest vocabularies
+### Latest vocabularies
 
-[Standard names][currentnames]{:.btn .btn-primary .btn-lg}
-[Area types][areatypes]{:.btn .btn-primary .btn-lg}
-[Standarized regions][regions]{:.btn .btn-primary .btn-lg}
+[Standard names](Data/cf-standard-names/current/build/cf-standard-name-table.html){:.btn .btn-primary .btn-lg}
+[Area types](Data/area-type-table/current/build/area-type-table.html){:.btn .btn-primary .btn-lg}
+[Standarized regions](Data/standardized-region-list/standardized-region-list.current.html){:.btn .btn-primary .btn-lg}
 
----
+### Questions or comments&#x2753;
+
+[CF GitHub Discussions](https://github.com/orgs/cf-convention/discussions) is the place for asking [questions](https://github.com/orgs/cf-convention/discussions/categories/q-a-about-using-cf) about how to use CF,<br>and for [discussions](https://github.com/orgs/cf-convention/discussions/categories/comments-and-ideas-for-changing-cf) and [announcements](https://github.com/orgs/cf-convention/discussions/categories/announcements-relevant-to-cf)
+
+</div>
+<div class="col-md-6" markdown="1">
+
+### Other resources
+
+See also the links in the navigation bar at the top of this page.
+
+Proposals for changing CF (GitHub issues):<br>[vocabulary](https://github.com/cf-convention/vocabularies/issues) (including standard names), [conventions](https://github.com/cf-convention/cf-conventions/issues), [website and governance](https://github.com/cf-convention/cf-convention.github.io/issues)
+
+[CF GitHub organisation](https://github.com/cf-convention)
 
-## Get involved
+[FAQ](faq.html)
+
+[List of software for working with CF](software.html)
+
+[List of projects and activities that use the CF metadata conventions](projects-activities.html)
+
+[Paper](https://doi.org/10.5194/gmd-10-4619-2017) describing the CF data model and reference software
+
+Overview of CF, presented at 2025 AGU: [DOI](https://doi.org/10.5281/zenodo.15015065) [PDF](https://zenodo.org/records/15015065/files/2024-12_AGU_CF_OpenSciPrize_presentation.pdf?download=1&preview=1)
+
+More detailed [presentation](Data/cf-documents/overview/viewgraphs.pdf) and [paper](Data/cf-documents/overview/article.pdf) about CF basics
+
+</div>
+</div>
+
+<div class="row">
+<div class="col-md-4" markdown="1">
+
+### Get involved
 
 CF is developed through open discussion on GitHub.
-If you would like to propose a change, make a suggestion, report a problem or ask a question, please [see here][discussion].
-Changes are decided according to the CF [governance arrangements][governance].
+If you would like to propose a change, make a suggestion, report a problem or ask a question, please [see here](discussion.html).
+Changes are decided according to the CF [governance arrangements](governance.html).
 The CF community embraces a philosophy of producing excellence by maintaining an open and welcoming culture and an environment that promotes debate and inquiry in a respectful, bold and intellectually rigorous fashion.
 
-![CF community at the 2024 conventions workshop](Data/media/images/CF2024_group2_cropped.jpg){: style="max-width:800px; height:auto;" } *CF community at the 2024 conventions workshop*
+</div>
 
----
+<div class="col-md-8">
 
-## Quick links
-
-See also the links in the navigation bar at the top of this page.
+<figure>
+<img src="Data/media/images/CF2024_group2_cropped.jpg" style="max-width:100%; height:auto;" alt="Members of the CF community at the 2024 conventions workshop">
+<figcaption>Members of the CF community at the 2024 conventions workshop</figcaption>
+</figure>
 
-* [CF GitHub Discussions][github_discussions]: announcements, forum for community discussion, questions and answers
-* Current proposals for changing CF (CF GitHub issues): [vocabulary][github_vocabularies] (including standard names), [conventions][github_conventions], this [website][github_website] (including governance)
-* [CF GitHub organisation][cf_github]
-* [CF FAQ][faq]
-* [List of software for working with CF](software.md)
-* [List of Projects and Activities that Use the CF Metadata Conventions](projects-activities.md)
-* [Paper][cfdmpaper] describing the CF data model and reference software
-* Overview of CF basics
-  * High-level presentation ([DOI](https://doi.org/10.5281/zenodo.15015065), [PDF](https://zenodo.org/records/15015065/files/2024-12_AGU_CF_OpenSciPrize_presentation.pdf?download=1&preview=1) - from 2024 AGU)
-  * More detailed [presentation][viewgraphs] and [paper][article]
-
-[api]: https://www.unidata.ucar.edu/software/netcdf
-[coards]: https://ferret.pmel.noaa.gov/noaa_coop/coop_cdf_profile.html
-[viewgraphs]: Data/cf-documents/overview/viewgraphs.pdf
-[article]: Data/cf-documents/overview/article.pdf
-[discussion]: discussion.md
-[governance]: governance.md
-[faq]: faq.md
-[releasedhtml]: Data/cf-conventions/cf-conventions-1.13/cf-conventions.html
-[releasedpdf]: Data/cf-conventions/cf-conventions-1.13/cf-conventions.pdf
-[workinghtml]: /cf-conventions/cf-conventions.html
-[workingpdf]: /cf-conventions/cf-conventions.pdf
-[currentnames]: Data/cf-standard-names/current/build/cf-standard-name-table.html
-[areatypes]: Data/area-type-table/current/build/area-type-table.html
-[regions]: Data/standardized-region-list/standardized-region-list.current.html
-[cfdmpaper]: https://doi.org/10.5194/gmd-10-4619-2017
-[github_conventions]: https://github.com/cf-convention/cf-conventions/issues
-[github_discuss]: https://github.com/cf-convention/discuss/issues
-[github_vocabularies]: https://github.com/cf-convention/vocabularies/issues
-[github_website]: https://github.com/cf-convention/cf-convention.github.io/issues
-[cf_github]: https://github.com/cf-convention
-[github_discussions]: https://github.com/orgs/cf-convention/discussions
-[github_askq]: https://github.com/orgs/cf-convention/discussions/new?category=q-a-about-using-cf
+</div>
+</div>
+<br>