fix: more visible sponsors button on prospectus

Author: phette23

assets/_scss/_buttons.scss

@@ -0,0 +1,8 @@
+// Most btn classes come from Bootstrap
+// See node_modules/bootstrap/scss/_buttons.scss
+.btn-extra-lg {
+    padding: 1.25rem 2.5rem;
+    font-size: 1.4rem;
+    line-height: 1.5;
+    border-radius: 0.3rem;
+}

assets/css/main.scss

@@ -29,3 +29,4 @@
 @import 'forms-pages';
 @import 'lanyards';
 @import 'a11y-fixes';
+@import 'buttons';

prospectus/index.html

@@ -12,6 +12,11 @@ <h1>Code4Lib {{site.data.conf.year}} Sponsor Prospectus</h1>
                 <p>
                     <img src="{{ site.baseurl }}/assets/img/persistent/prospectus-collage.jpg" title="Credit sdellis on Twitter" alt="Code4Lib Collage" width="100%">
                 </p>
+                {% if site.data.conf.sponsor-btn-link != nil %}
+                    <p class="text-center">
+                        <a class="btn btn-primary btn-extra-lg" href="{{site.data.conf.sponsor-btn-link}}">Sponsor Code4Lib {{site.data.conf.year}}</a>
+                    </p>
+                {% endif %}
                 <p>
                   The Code4Lib {{site.data.conf.year}} Conference, scheduled for {{site.data.conf.days[1].date-data | date: "%B %-d"}} - {{site.data.conf.days.last.date-data | date: "%-d"}}{% if site.data.conf.online-only-conference == false %} in {{site.data.conf.location}}{% endif %}, presents an opportunity for vendors, organizations, libraries, and projects to show their support for open and collaborative solutions for higher education, libraries, museums, and archives by providing financial support and attending the conference.
                 </p>