diff --git a/frontend/css/app.css b/frontend/css/app.css
index 556a5db..e81a79b 100644
--- a/frontend/css/app.css
+++ b/frontend/css/app.css
@@ -9,38 +9,50 @@
   --accent: #ea4335;
   --today-color: #4285f4;
 
-  --bg-app: #0e0e14;
-  --bg-topbar: #18181f;
-  --bg-sidebar: #18181f;
-  --bg-surface: #22222c;
-  --bg-hover: #2a2a38;
-  --bg-active: #32324a;
+  /* Layered surfaces — subtly cool-tinted, slightly more depth between layers
+     so panels read via elevation instead of hard table-like 1px borders */
+  --bg-app: #0c0c13;
+  --bg-topbar: #14141d;
+  --bg-sidebar: #14141d;
+  --bg-surface: #1d1d2a;
+  --bg-2: #16161f;        /* used by quarter month cards */
+  --bg-card: #1d1d2a;     /* used by recurrence day buttons */
+  --bg-hover: #262636;
+  --bg-active: #31314f;
 
   --text-1: #e8e8f0;
   --text-2: #9090aa;
   --text-3: #55556a;
   --border: #2e2e40;
   --border-light: #242438;
-  --scrollbar: #30303c;
+  --scrollbar: #36364a;
 
   --topbar-h: 64px;
   --sidebar-w: 256px;
-  --shadow: 0 2px 12px rgba(0,0,0,.45);
-  --shadow-lg: 0 8px 28px rgba(0,0,0,.55);
-  --radius: 8px;
-  --radius-sm: 4px;
-  --transition: .15s ease;
+  --shadow-sm: 0 1px 3px rgba(0,0,0,.30);
+  --shadow: 0 6px 20px rgba(0,0,0,.40);
+  --shadow-lg: 0 16px 44px rgba(0,0,0,.55);
+  --radius-lg: 20px;
+  --radius: 14px;
+  --radius-sm: 9px;
+  --transition: .18s cubic-bezier(.4, 0, .2, 1);
+  --ring: 0 0 0 3px var(--primary-dim);
 }
 
 /* ── Reset ──────────────────────────────────────────────── */
 *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
 html, body { height: 100%; overflow: hidden; }
 body {
-  font-family: 'Google Sans', 'Roboto', system-ui, sans-serif;
+  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto,
+               'Helvetica Neue', system-ui, sans-serif;
   background: var(--bg-app);
   color: var(--text-1);
   font-size: 14px;
   line-height: 1.5;
+  letter-spacing: .1px;
+  -webkit-font-smoothing: antialiased;
+  -moz-osx-font-smoothing: grayscale;
+  text-rendering: optimizeLegibility;
 }
 input, select, textarea, button { font-family: inherit; font-size: inherit; color: inherit; }
 button { cursor: pointer; border: none; background: none; }
@@ -59,14 +71,21 @@ a { color: var(--primary); text-decoration: none; }
 .btn {
   display: inline-flex; align-items: center; gap: 6px;
   padding: 8px 16px; border-radius: 20px;
-  font-weight: 500; transition: background var(--transition), color var(--transition);
+  font-weight: 500;
+  transition: background var(--transition), color var(--transition),
+              box-shadow var(--transition), transform var(--transition),
+              filter var(--transition);
   white-space: nowrap;
 }
+.btn:active { transform: translateY(1px); }
+.btn:focus-visible { outline: none; box-shadow: var(--ring); }
 .btn-primary {
   background: var(--primary);
+  background: linear-gradient(135deg, var(--primary), color-mix(in srgb, var(--primary) 80%, #14141d));
   color: #fff;
+  box-shadow: 0 2px 10px var(--primary-dim);
 }
-.btn-primary:hover { filter: brightness(1.12); }
+.btn-primary:hover { filter: brightness(1.10); box-shadow: 0 5px 18px var(--primary-dim); }
 .btn-secondary {
   background: var(--bg-surface);
   color: var(--text-1);
@@ -93,11 +112,14 @@ a { color: var(--primary); text-decoration: none; }
 .icon-btn {
   display: inline-flex; align-items: center; justify-content: center;
   width: 40px; height: 40px; border-radius: 50%;
-  color: var(--text-2); transition: background var(--transition);
+  color: var(--text-2);
+  transition: background var(--transition), color var(--transition), transform var(--transition);
   flex-shrink: 0;
 }
 .icon-btn svg { width: 20px; height: 20px; fill: currentColor; }
 .icon-btn:hover { background: var(--bg-hover); color: var(--text-1); }
+.icon-btn:active { transform: scale(.92); }
+.icon-btn:focus-visible { outline: none; box-shadow: var(--ring); }
 
 /* ── Auth Screens ───────────────────────────────────────── */
 .auth-screen {
@@ -144,11 +166,12 @@ a { color: var(--primary); text-decoration: none; }
   padding: 10px 12px;
   color: var(--text-1);
   outline: none;
-  transition: border-color var(--transition);
+  transition: border-color var(--transition), box-shadow var(--transition);
   width: 100%;
 }
 .form-group input:focus, .form-group select:focus, .form-group textarea:focus {
   border-color: var(--primary);
+  box-shadow: var(--ring);
 }
 .form-group textarea { resize: vertical; }
 
@@ -289,7 +312,8 @@ a { color: var(--primary); text-decoration: none; }
   position: fixed; top: 0; left: 0; right: 0; z-index: 100;
   height: var(--topbar-h);
   background: var(--bg-topbar);
-  border-bottom: 1px solid var(--border);
+  border-bottom: 1px solid var(--border-light);
+  box-shadow: var(--shadow-sm);
   display: flex; align-items: center;
   padding: 0 8px;
   gap: 8px;
@@ -302,15 +326,16 @@ a { color: var(--primary); text-decoration: none; }
 .view-title { font-size: 20px; font-weight: 400; color: var(--text-1); white-space: nowrap; padding-left: 8px; }
 .topbar-right { display: flex; align-items: center; gap: 4px; }
 
-.view-switcher { display: flex; background: var(--bg-surface); border-radius: 20px; overflow: hidden; border: 1px solid var(--border); }
+.view-switcher { display: flex; gap: 2px; padding: 3px; background: var(--bg-surface); border-radius: 22px; border: 1px solid var(--border-light); }
 .view-btn {
   padding: 6px 14px; font-size: 13px; font-weight: 500;
   color: var(--text-2);
-  transition: background var(--transition), color var(--transition);
-  border-radius: 20px;
+  transition: background var(--transition), color var(--transition), box-shadow var(--transition);
+  border-radius: 18px;
 }
 .view-btn:hover { background: var(--bg-hover); color: var(--text-1); }
-.view-btn.active { background: var(--primary-dim); color: var(--primary); }
+.view-btn:focus-visible { outline: none; box-shadow: var(--ring); }
+.view-btn.active { background: var(--primary-dim); color: var(--primary); font-weight: 600; box-shadow: inset 0 0 0 1px var(--primary-dim); }
 
 .user-menu-wrapper { position: relative; }
 .user-avatar {
@@ -353,7 +378,7 @@ a { color: var(--primary); text-decoration: none; }
 .sidebar {
   width: var(--sidebar-w);
   background: var(--bg-sidebar);
-  border-right: 1px solid var(--border);
+  border-right: 1px solid var(--border-light);
   flex-shrink: 0;
   overflow-y: auto;
   overflow-x: hidden;
@@ -640,7 +665,7 @@ a { color: var(--primary); text-decoration: none; }
   position: absolute;
   height: 18px; line-height: 18px;
   font-size: 11px; font-weight: 500;
-  padding: 0 6px; border-radius: 3px;
+  padding: 0 6px; border-radius: 6px;
   cursor: pointer; pointer-events: all;
   white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
 }
@@ -691,7 +716,7 @@ a { color: var(--primary); text-decoration: none; }
 
 /* Timed events */
 .timed-event {
-  position: absolute; border-radius: 4px;
+  position: absolute; border-radius: 7px;
   padding: 2px 4px; cursor: pointer; overflow: hidden;
   font-size: 11px; font-weight: 500;
   border-left: 3px solid rgba(0,0,0,.25);
@@ -723,16 +748,19 @@ a { color: var(--primary); text-decoration: none; }
   flex-direction: column;
   min-width: 0;
   background: var(--bg-2);
-  border: 1px solid var(--border);
-  border-radius: 8px;
+  border: 1px solid var(--border-light);
+  border-radius: var(--radius);
   overflow: hidden;
+  box-shadow: var(--shadow-sm);
+  transition: box-shadow var(--transition), transform var(--transition);
 }
+.qtr-month:hover { box-shadow: var(--shadow); transform: translateY(-2px); }
 .qtr-month-name {
   font-size: 13px;
   font-weight: 600;
   color: var(--text-1);
   padding: 10px 12px 8px;
-  border-bottom: 1px solid var(--border);
+  border-bottom: 1px solid var(--border-light);
   letter-spacing: .3px;
 }
 .qtr-month-grid { padding: 6px 8px 8px; }
@@ -835,17 +863,27 @@ a { color: var(--primary); text-decoration: none; }
 /* ── Modals ─────────────────────────────────────────────── */
 .modal-overlay {
   position: fixed; inset: 0; z-index: 500;
-  background: rgba(0,0,0,.6);
+  background: rgba(8,8,14,.55);
+  -webkit-backdrop-filter: blur(5px);
+  backdrop-filter: blur(5px);
   display: flex; align-items: center; justify-content: center;
   padding: 16px;
 }
 .modal-card {
   background: var(--bg-surface);
-  border: 1px solid var(--border);
+  border: 1px solid var(--border-light);
   border-radius: var(--radius);
   width: 100%;
   max-height: 90vh; overflow-y: auto;
   box-shadow: var(--shadow-lg);
+  animation: card-in .2s cubic-bezier(.4, 0, .2, 1);
+}
+@keyframes card-in {
+  from { opacity: 0; transform: translateY(8px) scale(.985); }
+  to   { opacity: 1; transform: none; }
+}
+@media (prefers-reduced-motion: reduce) {
+  .modal-card { animation: none; }
 }
 .modal-header {
   display: flex; align-items: center;
@@ -1145,7 +1183,7 @@ a { color: var(--primary); text-decoration: none; }
 .month-span-event {
   position: absolute;
   height: 18px; line-height: 18px;
-  border-radius: 3px; padding: 0 6px;
+  border-radius: 6px; padding: 0 6px;
   font-size: 11px; font-weight: 500;
   white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
   cursor: pointer; color: #fff;