Maybe/app/views/budgets/show.html.erb

<div class="pb-12">
  <%= render "budgets/budget_header",
            budget: @budget,
            previous_budget: @previous_budget,
            next_budget: @next_budget,
            latest_budget: @latest_budget %>

  <div class="flex items-start gap-4">
    <div class="w-[300px] space-y-4">
      <div class="h-[300px] bg-white rounded-xl shadow-xs p-8 border border-gray-100">
        <% if @budget.available_to_allocate.negative? %>
          <%= render "budgets/over_allocation_warning", budget: @budget %>
        <% else %>
          <%= render "budgets/budget_donut", budget: @budget %>
        <% end %>
      </div>

      <div>
        <% if @budget.initialized? && @budget.available_to_allocate.positive? %>
          <div class="flex gap-2 mb-2 rounded-lg bg-alpha-black-25 p-1">
            <% base_classes = "rounded-md px-2 py-1 flex-1 text-center" %>
            <% selected_tab = params[:tab].presence || "budgeted" %>

            <%= link_to "Budgeted",
                        budget_path(@budget, tab: "budgeted"),
                        class: class_names(
                          base_classes,
                          "bg-white shadow-xs text-gray-900": selected_tab == "budgeted",
                          "text-gray-500": selected_tab != "budgeted"
                        ) %>

            <%= link_to "Actual",
                        budget_path(@budget, tab: "actuals"),
                        class: class_names(
                          base_classes,
                          "bg-white shadow-xs text-gray-900": selected_tab == "actuals",
                          "text-gray-500": selected_tab != "actuals"
                        ) %>
          </div>

          <div class="bg-white rounded-xl shadow-xs border border-gray-100">
            <%= render selected_tab == "budgeted" ? "budgets/budgeted_summary" : "budgets/actuals_summary", budget: @budget %>
          </div>
        <% else %>
          <div class="bg-white rounded-xl shadow-xs border border-gray-100">
            <%= render "budgets/actuals_summary", budget: @budget %>
          </div>
        <% end %>
      </div>
    </div>

    <div class="grow bg-white rounded-xl shadow-xs p-4 border border-gray-100">
      <div class="flex items-center justify-between mb-4">
        <h2 class="text-lg font-medium">Categories</h2>

        <%= link_to budget_budget_categories_path(@budget), class: "btn btn--secondary flex items-center gap-2" do %>
          <%= icon "settings-2", color: "gray" %>
          <span>Edit</span>
        <% end %>
      </div>

      <div class="bg-gray-25 rounded-xl p-1">
        <%= render "budgets/budget_categories", budget: @budget %>
      </div>
    </div>
  </div>
</div>