feat: Add splash screen

web/splash/style.css

@@ -0,0 +1,43 @@
+body, html {
+  margin:0;
+  height:100%;
+  background: #ffffff;
+  background-image: url("img/light-background.png");
+  background-size: 100% 100%;
+}
+
+.center {
+  margin: 0;
+  position: absolute;
+  top: 50%;
+  left: 50%;
+  -ms-transform: translate(-50%, -50%);
+  transform: translate(-50%, -50%);
+}
+
+.contain {
+  display:block;
+  width:100%; height:100%;
+  object-fit: contain;
+}
+
+.stretch {
+  display:block;
+  width:100%; height:100%;
+}
+
+.cover {
+  display:block;
+  width:100%; height:100%;
+  object-fit: cover;
+}
+
+@media (prefers-color-scheme: dark) {
+  body {
+    margin:0;
+    height:100%;
+    background: #000000;
+    background-image: url("img/dark-background.png");
+    background-size: 100% 100%;
+  }
+}