Fix the settings tabs, and space a form from what follows it

**The Audio tab rendered nothing.** The tabs are radios plus sibling
selectors, and the CSS named every tab twice -- once to highlight its label,
once to show its panel. A tab added without also adding those two rules gets a
label that selects nothing, which is not something anyone catches in review; it
looks like a blank page.

Replaced with rules that derive what they can. The active label is
`input:checked + .tabs__tab`, which needs to know nothing at all. The panel is
matched by position -- CSS cannot compare a radio's id with a panel's data-tab
-- so the Nth radio shows the Nth panel. Both lists render in the same order
and a conditional tab drops out of both at once, so they cannot drift. There is
a test asserting the two orders match, including with Audio absent.

**A card following a form sat flush against Save.** The "Try it" panel on the
search page read as another field of the settings form. The gap belongs to the
form rather than to its action row: the action row is always its form's last
child, so a bottom margin there has nothing to push away from. Adds
`.form-actions` and a bottom margin on a form that is a direct child of an
admin page.

Also says plainly in the dictation settings that a server hosting one model
ignores the model field, so `whisper-1` there is a label rather than a
selection.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/lembas/web/static/css/admin.css

@@ -72,23 +72,64 @@
 
 .tabs__panel { display: none; }
 
-/* Each radio activates its own label and its own panel. Written out because
-   CSS has no way to derive one from the other. */
-#tab-account:checked ~ label[for="tab-account"],
-#tab-models:checked ~ label[for="tab-models"],
-#tab-appearance:checked ~ label[for="tab-appearance"],
-#tab-security:checked ~ label[for="tab-security"] {
+/* The active tab's label. Each radio is immediately followed by its own label,
+   so this needs to know nothing about how many tabs there are or what they are
+   called. */
+.tabs__bar input:checked + .tabs__tab {
   color: var(--ink);
   border-bottom-color: var(--accent);
 }
-.tabs__bar:has(#tab-account:checked) ~ .tabs__body [data-tab="tab-account"],
-.tabs__bar:has(#tab-models:checked) ~ .tabs__body [data-tab="tab-models"],
-.tabs__bar:has(#tab-appearance:checked) ~ .tabs__body [data-tab="tab-appearance"],
-.tabs__bar:has(#tab-security:checked) ~ .tabs__body [data-tab="tab-security"] {
+
+/*
+  The active panel, matched by position.
+
+  CSS cannot compare a radio's id with a panel's data-tab, so this used to name
+  every tab twice -- and a tab added without also adding its two rules here
+  rendered a label that selected nothing. That is not a failure anyone spots in
+  review; it looks like a blank page.
+
+  Position is derivable, so it is used instead: the Nth radio shows the Nth
+  panel. Both lists are rendered in the same order, and a conditional tab drops
+  out of both at once, so they cannot drift apart. :nth-of-type counts by
+  element name, which is why the panels are <section> and the alerts above them
+  are <div> -- the alerts are not counted.
+
+  Enumerated to eight, comfortably more than exist. A ninth tab needs one line.
+*/
+.tabs__bar:has(input:nth-of-type(1):checked) ~ .tabs__body .tabs__panel:nth-of-type(1),
+.tabs__bar:has(input:nth-of-type(2):checked) ~ .tabs__body .tabs__panel:nth-of-type(2),
+.tabs__bar:has(input:nth-of-type(3):checked) ~ .tabs__body .tabs__panel:nth-of-type(3),
+.tabs__bar:has(input:nth-of-type(4):checked) ~ .tabs__body .tabs__panel:nth-of-type(4),
+.tabs__bar:has(input:nth-of-type(5):checked) ~ .tabs__body .tabs__panel:nth-of-type(5),
+.tabs__bar:has(input:nth-of-type(6):checked) ~ .tabs__body .tabs__panel:nth-of-type(6),
+.tabs__bar:has(input:nth-of-type(7):checked) ~ .tabs__body .tabs__panel:nth-of-type(7),
+.tabs__bar:has(input:nth-of-type(8):checked) ~ .tabs__body .tabs__panel:nth-of-type(8) {
   display: block;
 }
 .tabs__tab:has(:focus-visible) { outline: 2px solid var(--accent); outline-offset: -2px; }
 
+/*
+  A form's action row, and the space after the form it closes.
+
+  Not a plain .btn-row: a settings form is a stack of cards, and Save has to
+  read as belonging to the cards above it rather than to whatever comes next.
+  The gap that matters is the one *after* the form -- a card following it (the
+  "Try it" panel on the search page, say) otherwise sits flush against Save and
+  looks like another field of the same form. That margin therefore belongs to
+  the form, not to the action row: the action row is always its form's last
+  child, so a bottom margin there would have nothing to push away from.
+*/
+.form-actions {
+  display: flex;
+  align-items: center;
+  gap: var(--sp-2);
+  flex-wrap: wrap;
+  margin-top: var(--sp-5);
+}
+
+.admin-page > form { margin-bottom: var(--sp-8); }
+.admin-page > form:last-child { margin-bottom: 0; }
+
 /* --- Cards ----------------------------------------------------------------- */
 .card {
   background: var(--surface);

src/lembas/web/templates/admin/audio.html

@@ -61,8 +61,9 @@
         <input class="input" id="stt-model" name="stt_model"
                value="{{ values.stt_model }}" placeholder="whisper-1">
         <p class="field__hint">
-          Sent even to servers that only host one; a router in front of several
-          needs it.
+          A server hosting one model <strong>ignores this</strong> and uses
+          whatever it was started with — <code>whisper-1</code> is then just a
+          label. It only selects anything on a server that hosts several.
         </p>
       </div>
       <div class="field">
@@ -179,6 +180,6 @@
     <div id="audio-test-tts"></div>
   </section>
 
-  <div class="btn-row"><button class="btn btn--primary" type="submit">Save settings</button></div>
+  <div class="form-actions"><button class="btn btn--primary" type="submit">Save settings</button></div>
 </form>
 {% endblock %}

src/lembas/web/templates/admin/general.html

@@ -84,6 +84,6 @@
     </p>
   </section>
 
-  <div class="btn-row"><button class="btn btn--primary" type="submit">Save settings</button></div>
+  <div class="form-actions"><button class="btn btn--primary" type="submit">Save settings</button></div>
 </form>
 {% endblock %}

src/lembas/web/templates/admin/search.html

@@ -128,7 +128,7 @@
     </div>
   </section>
 
-  <div class="btn-row"><button class="btn btn--primary" type="submit">Save settings</button></div>
+  <div class="form-actions"><button class="btn btn--primary" type="submit">Save settings</button></div>
 </form>
 
 <section class="card">