Add Mario Day feature: implement CSS and JS for Mario animations and visibility toggle

Jellyfin.Plugin.Seasonals/Web/marioday.css

@@ -0,0 +1,77 @@
+.marioday-container {
+    display: block;
+    position: fixed;
+    top: 0;
+    left: 0;
+    width: 100%;
+    height: 100%;
+    pointer-events: none;
+    z-index: 10000;
+    contain: strict;
+    overflow: hidden;
+}
+
+.mario-wrapper {
+    position: absolute;
+    bottom: 5px;
+    left: -100px;
+    animation: mario-run 15s linear infinite;
+    will-change: left, transform;
+}
+
+.mario-runner {
+    width: 64px;
+    height: auto;
+    image-rendering: crisp-edges;
+    image-rendering: pixelated;
+    display: block;
+    will-change: transform;
+}
+
+.mario-jump {
+    animation: jump-arc 0.8s ease-in-out;
+}
+
+/* 8-bit coin styling */
+.mario-coin {
+    position: absolute;
+    width: 32px;
+    height: 32px;
+    background-color: #ffd700;
+    border: 4px solid #b8860b;
+    border-radius: 50%;
+    box-shadow: inset 4px 4px 0 #fffbea, inset -4px -4px 0 #daa520;
+    animation: pop-up-arc 2s forwards;
+}
+
+.mario-coin::after {
+    content: '';
+    position: absolute;
+    top: 6px;
+    left: 10px;
+    width: 4px;
+    height: 12px;
+    background: #daa520;
+}
+
+@keyframes mario-run {
+    0% { left: -100px; transform: scaleX(1); }
+    45% { left: 110vw; transform: scaleX(1); }
+    50% { left: 110vw; transform: scaleX(-1); }
+    95% { left: -100px; transform: scaleX(-1); }
+    100% { left: -100px; transform: scaleX(1); }
+}
+
+@keyframes pop-up-arc {
+    0%   { transform: translateY(0) rotateY(0deg); opacity: 0; animation-timing-function: ease-out; }
+    20%  { opacity: 1; }
+    50%  { transform: translateY(-30vh) rotateY(360deg); opacity: 1; animation-timing-function: ease-in; }
+    90%  { opacity: 1; }
+    100% { transform: translateY(20vh) rotateY(720deg); opacity: 0; }
+}
+
+@keyframes jump-arc {
+    0%   { transform: translateY(0); }
+    50%  { transform: translateY(-25vh); }
+    100% { transform: translateY(0); }
+}