Move all cards to 1 grid, make header appear clickable

Author: jaladh-singhal

_static/custom.css

@@ -1,7 +1,4 @@
-.grid-item-span-all-cols {
-    grid-column: 1 / -1;
+html.light a.myst-card > .myst-card-header {
+    /* header of a link card in light mode */
+    background-color: #eff6ff; /* Tailwind blue-50, used by info admonition */
 }
-
-.grid-item-span-all-cols > .myst-card {
-    margin: 0;
-}

tutorials/euclid_access/euclid.md

@@ -6,87 +6,64 @@ It carries two instruments: the VISible instrument (VIS) and the Near-Infrared S
 [Quick Release 1 (Q1)](https://irsa.ipac.caltech.edu/data/Euclid/docs/overview_q1.html) was released in March 2025 and consists of approximately 35 TB of imaging, spectroscopy, and catalogs, covering four non-contiguous fields totaling 63 square degrees.
 Data products include MERged mosaics of calibrated and stacked frames; combined infrared spectra (SIR); and catalogs of MER objects, photometric redshifts and classifications (PHZ), and spectroscopic redshifts and line measurements (SPE).
 
-## Images
+
+````{grid} 1 2 2 3
 
 ```{card}
 :link: 1_Euclid_intro_MER_images.md
-:header: **MER Mosaics**
+:header: [MER Image Mosaics →](1_Euclid_intro_MER_images.md)
 Retrieve both a full MER mosaic image and multi-wavelength cutouts, then subtract the background from the cutouts and extract sources.
 ```
 
-## Spectra
-
 ```{card}
 :link: 3_Euclid_intro_1D_spectra.md
-:header: **SIR 1D Spectra**
+:header: [SIR 1D Spectra →](3_Euclid_intro_1D_spectra.md)
 Load a galaxy spectrum and plot it. Understand the wavelength, flux, and mask values.
 ```
 
-## Catalogs
-
-````{grid} 1 1 2 2
-
 ```{card}
 :link: 2_Euclid_intro_MER_catalog.md
-:header: **MER Catalogs**
+:header: [MER Catalogs →](2_Euclid_intro_MER_catalog.md)
 
 Explore the columns in the MER final catalog, query for stars, and create a color-magnitude diagram.
 ```
 
 ```{card}
 :link: 5_Euclid_intro_SPE_catalog.md
-:header: **SPE Catalogs**
+:header: [SPE Catalogs →](5_Euclid_intro_SPE_catalog.md)
 
 Join the SPE and MER catalogs and query for galaxies with H-alpha line detections, then plot the SIR spectrum of a galaxy with a high SNR H-alpha line measurement.
 ```
 
-```{div .grid-item-span-all-cols}
 ```{card}
 :link: 4_Euclid_intro_PHZ_catalog.md
-:header: **PHZ Catalogs**
+:header: [PHZ Catalogs →](4_Euclid_intro_PHZ_catalog.md)
 
-Join the PHZ and MER catalogs and do a box search for galaxies with quality redshifts, load a MER mosaic cutout of the box, and plot the cutout with the catalog results overlaid.
-Then plot the SIR spectrum of the brightest galaxy and look at a MER mosaic cutout of the galaxy in Firefly.
+Join the PHZ and MER catalogs to query galaxies with quality redshifts in a box region, create MER mosaic cutouts with catalog overlays, and plot the brightest galaxy's SIR spectrum.
 ```
 
-
-````
-
-### Merged Objects HATS Catalog
-This product was created by IRSA and contains the Euclid MER, PHZ, and SPE catalogs in a single [HATS](https://hats.readthedocs.io/en/latest/) catalog.
-
-````{grid} 1 1 2 2
-
 ```{card}
-:link: ../parquet-catalog-demos/euclid-q1-hats/1-euclid-q1-hats-intro.md
-:header: **Introduction**
-Understand the content and format of the Euclid Q1 Merged Objects HATS Catalog, then perform a basic query.
+:link: ../cloud_access/euclid-cloud-access.md
+:header: [Cloud Access →](../cloud_access/euclid-cloud-access.md)
+Browse the on-cloud copy of Q1, then efficiently retrieve a MER mosaic cutout and a SIR spectrum.
 ```
 
 ```{card}
-:link: ../parquet-catalog-demos/euclid-q1-hats/4-euclid-q1-hats-magnitudes.md
-:header: **Magnitudes**
-Review the types of flux measurements available, load template-fit and aperture magnitudes, and plot distributions and comparisons for different object types.
+:link: Euclid_ERO.md
+:header: [ERO Star Clusters →](Euclid_ERO.md)
+Create multi-wavelength ERO image cutouts of a globular cluster, extract sources, and measure photometry. Match Gaia sources with Euclid ERO catalogs, then visualize with Firefly.
 ```
 
-````
-
-
-## Special Topics
-
-````{grid} 1 1 2 2
-
-```{card}
-:link: ../cloud_access/euclid-cloud-access.md
-:header: **Cloud Access**
-Browse the on-cloud copy of Q1, then efficiently retrieve a MER mosaic cutout and a SIR spectrum.
+```{card} Introduction
+:link: ../parquet-catalog-demos/euclid-q1-hats/1-euclid-q1-hats-intro.md
+:header: [Merged Objects Catalog →](../parquet-catalog-demos/euclid-q1-hats/1-euclid-q1-hats-intro.md)
+Understand the content and format of the Euclid Q1 Merged Objects HATS Catalog, then perform a basic query.
 ```
 
-```{card}
-:link: Euclid_ERO.md
-:header: **ERO Star Clusters**
-[*Deprecated; ERO is superseded by Q1*] Create multi-wavelength ERO (Early Release Observations) image cutouts of a globular cluster, extract sources, and measure photometry.
-Then load Gaia sources at the location of the globular cluster, match with Euclid ERO catalogs, and visualize the results with Firefly.
+```{card} Magnitudes
+:link: ../parquet-catalog-demos/euclid-q1-hats/4-euclid-q1-hats-magnitudes.md
+:header: [Merged Objects Catalog →](../parquet-catalog-demos/euclid-q1-hats/4-euclid-q1-hats-magnitudes.md)
+Review the types of flux measurements available, load template-fit and aperture magnitudes, and plot distributions and comparisons for different object types.
 ```
 
 ````