Dark: Fix hero colors on homepage

We can now use `[data-theme="dark"]` selector in CSS to defined styles
specifically for dark mode. This follows common web dev patterns and
gives little overhead.

- Hero
  - Added `wave_black` SVG which copies `wave_white` as is but uses the
    site's dark mode background color.

3 files changed, 89 insertions, 0 deletions

diff --git a/pydis_site/static/css/home/index.css b/pydis_site/static/css/home/index.css
index e117a35b..23e27be1 100644
--- a/pydis_site/static/css/home/index.css
+++ b/pydis_site/static/css/home/index.css
@@ -91,6 +91,11 @@ h1 {
     height: 26px;
     z-index: 3;
 }
+[data-theme="dark"] {
+    #bottom-wave {
+        background: url(../../images/waves/wave_black.svg) repeat-x !important;
+    }
+}
 
 @keyframes wave {
   0% {
@@ -176,6 +181,11 @@ h1 {
 #projects .card:hover .card-header-title {
     color: #363636;
 }
+[data-theme="dark"] {
+    #projects .card:hover .card-header-title {
+        color: #CAD6FF;
+    }
+}
 
 #projects .card-content {
     padding-top: 8px;
diff --git a/pydis_site/static/images/waves/wave_black.svg b/pydis_site/static/images/waves/wave_black.svg
new file mode 100644
index 00000000..899fe2f9
--- /dev/null
+++ b/pydis_site/static/images/waves/wave_black.svg
@@ -0,0 +1,77 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<svg
+   xmlns:dc="http://purl.org/dc/elements/1.1/"
+   xmlns:cc="http://creativecommons.org/ns#"
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:svg="http://www.w3.org/2000/svg"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   width="1600"
+   height="28.745832"
+   version="1.1"
+   id="svg11"
+   sodipodi:docname="wavew.svg"
+   inkscape:version="1.0.1 (3bc2e813f5, 2020-09-07)">
+  <metadata
+     id="metadata15">
+    <rdf:RDF>
+      <cc:Work
+         rdf:about="">
+        <dc:format>image/svg+xml</dc:format>
+        <dc:type
+           rdf:resource="http://purl.org/dc/dcmitype/StillImage" />
+        <dc:title></dc:title>
+      </cc:Work>
+    </rdf:RDF>
+  </metadata>
+  <sodipodi:namedview
+     pagecolor="#ffffff"
+     bordercolor="#666666"
+     borderopacity="1"
+     objecttolerance="10"
+     gridtolerance="10"
+     guidetolerance="10"
+     inkscape:pageopacity="0"
+     inkscape:pageshadow="2"
+     inkscape:window-width="2560"
+     inkscape:window-height="1409"
+     id="namedview13"
+     showgrid="false"
+     inkscape:zoom="1.44625"
+     inkscape:cx="884.40031"
+     inkscape:cy="-61.865141"
+     inkscape:window-x="4880"
+     inkscape:window-y="677"
+     inkscape:window-maximized="1"
+     inkscape:current-layer="svg11"
+     fit-margin-top="0"
+     fit-margin-left="0"
+     fit-margin-right="0"
+     fit-margin-bottom="0" />
+  <defs
+     id="defs7">
+    <linearGradient
+       id="a"
+       x1="0.5"
+       x2="0.5"
+       y1="-0.10958999"
+       y2="1">
+      <stop
+         stop-color="#57BBC1"
+         stop-opacity=".25"
+         offset="0%"
+         id="stop2" />
+      <stop
+         stop-color="#015871"
+         offset="100%"
+         id="stop4" />
+    </linearGradient>
+  </defs>
+  <path
+     fill="url(#a)"
+     fill-rule="evenodd"
+     d="M 1599.995,17.566918 C 1289,17.566918 1190.102,-0.03623696 789,5.6042811e-5 389,5.6042811e-5 289,17.566918 0,17.566918 v 11.178914 h 1600 c 0,0 -0.01,-6.968673 -0.01,-11.178914 z"
+     id="path9"
+     style="fill:#2C2F33;fill-opacity:1;stroke-width:0.381026" />
+</svg>
diff --git a/pydis_site/static/js/base/navbar.js b/pydis_site/static/js/base/navbar.js
index 04850add..2a57cad4 100644
--- a/pydis_site/static/js/base/navbar.js
+++ b/pydis_site/static/js/base/navbar.js
@@ -30,6 +30,8 @@ function setStyleSheets(newTheme) {
             darkStylesheet.disabled = false;
             break;
     }
+
+    document.querySelector("html").setAttribute("data-theme", newTheme);
 }
 
 // Reflect chosen theme on the switch toggle.