What this page combines
The schedule links stay in normal flow before sticking. Decorative and content layers use 1, 2, and 3 instead of arbitrary huge z-index values.
Morning observation walk
Meet beside the visitor centre, compare field-note methods, and record the river conditions in small groups.
Afternoon mapping session
Turn the morning observations into a shared map while keeping source notes and image descriptions attached.
Evening review
Review changes in light and water, then list which conclusions are observations and which remain hypotheses.
Why these choices?
The hero and schedule cards establish containing blocks for their labels. Schedule links use flex: 1 1 9rem, so they grow evenly and wrap when the row narrows. Sticky navigation uses a threshold and layer 10, while the fixed back-to-top link uses layer 20 and leaves clear page padding.