Logo is now d-block with fixed height and auto margin.

This fixed the vertical space allocation for Firefox.

templates/home.html

@@ -11,7 +11,7 @@
         <div class="scrollable-md">
           <svg class="w-100 h-100 position-absolute z-lowest" id="graph"></svg>
           <header class="my-3 mx-3">
-            <h1 class="text-center"><img src="{{ '/images/logo.svg' | url}}" alt="Mittelab" class="logo m-2"></h1>
+            <h1><img src="{{ '/images/logo.svg' | url}}" alt="Mittelab" class="logo d-block mx-auto"></h1>
             <p class="text-monospace text-center lead">
               {{ this.description }}
             </p>

templates/page.html

@@ -5,8 +5,8 @@
     <div class="row h-100">
       <div class="col-md-5 col-lg-4 col-xl-3 col-xxl-2 px-0">
         <svg class="w-100 h-100 position-absolute z-lowest" id="graph"></svg>
-        <header class="my-3 text-center">
-          <a href="/"><img src="{{ '/images/logo.svg' | url}}" alt="Mittelab" class="logo m-2"></a>
+        <header class="my-3">
+          <h1><a href="/"><img src="{{ '/images/logo.svg' | url}}" alt="Mittelab" class="logo mx-auto d-block"></a></h1>
         </header>
         <nav class="w-100 px-3">
           {% include 'nav.html' %}