Adding some preliminary RDT feeddown documentation

Author: Sasha Jade Horney

docs/assets/images/rdtfeeddown_gui/CorrectionResponseScreenshot.png

@@ -100,3 +100,46 @@ a.cern_internal {
 .clickImg {
   cursor: pointer;
 }
+
+.guilabel {
+    white-space: nowrap;
+    padding: 0.5px 6px;
+    width: fit-content;
+    border-radius: 4px;
+    font-weight: bold;
+    display: inline-block;
+}
+
+.guilabel {
+    white-space: nowrap;
+    padding: 0.5px 12px;
+    width: fit-content;
+    border-radius: 0px;
+    font-weight: bold;
+    display: inline-block;
+    background: var(--guilabel-bg, #3c3c3c);
+    color: var(--guilabel-fg, #ffffff);
+    box-shadow: 0 1px 2px rgba(0,0,0,0.12);
+    border: white;
+    font-size: 1em;
+}
+
+a.tab-link {
+    display: inline-block;
+    padding: 0.15em 0.7em;
+    border-radius: 0px;
+    background: #3c3c3c;
+    color: #e0e0e0;
+    font-family: inherit;
+    font-size: 1em;
+    font-weight: 600;
+    text-transform: uppercase;
+    text-decoration: none;
+    border: 1.5px solid #232323;
+    box-shadow: 0 2px 6px rgba(21,101,192,0.08);
+    transition: background 0.2s, color 0.2s, border-bottom 0.2s;
+}
+a.tab-link:hover, a.tab-link:focus {
+    background: #484848;
+    color: #ffffff;
+}