design: landing page effects and polish

- radial gradient glow background
- card hover: translateY(-4px) + blue glow shadow
- gradient on cards for depth
- OSCloud logo in nav instead of blue M
- wider card grid and footer (1100px)
- footer separator between OSCloud and links
- vertically centered content
- faster transitions (0.15s)

style/mxchat.css

@@ -87,6 +87,7 @@ html { height: 100%; -webkit-font-smoothing: antialiased; -moz-osx-font-smoothin
 body {
   min-height: 100vh;
   display: flex;
+  justify-content: center;
   flex-direction: column;
   font-family: var(--font-body);
   font-size: 15px;
@@ -328,7 +329,7 @@ a:hover { color: var(--accent); text-decoration: underline; }
   display: grid;
   grid-template-columns: repeat(2, minmax(0, 1fr));
   gap: 16px;
-  max-width: 900px;
+  max-width: 1100px;
   margin: 0 auto;
   padding: 16px 24px 40px;
 }
@@ -344,7 +345,9 @@ a:hover { color: var(--accent); text-decoration: underline; }
   transition: all var(--transition);
 }
 .link-card:hover {
-  border-color: var(--border-hover);
+  transform: translateY(-4px);
+  border-color: var(--accent-light);
+  box-shadow: 0 4px 24px rgba(21, 101, 192, 0.25);
   background: var(--bg-card-hover);
   text-decoration: none;
 }
@@ -477,7 +480,7 @@ a:hover { color: var(--accent); text-decoration: underline; }
    ============================================ */
 .site-footer {
   padding: 24px 32px;
-  max-width: 900px;
+  max-width: 1100px;
   margin: 48px auto 0;
   border-top: 0.5px solid var(--border);
   display: flex;
@@ -485,6 +488,7 @@ a:hover { color: var(--accent); text-decoration: underline; }
   align-items: center;
   font-size: 12px;
   color: var(--text-dim);
+  margin-top: auto;
 }
 .footer-links {
   display: flex;