feat(phase-4): visual polish — font stack, shadow system, transitions, micro-interactions

Phase 4: Visual Polish

4.1 Font Stack Upgrade:
- Add --font-display token for headings
- Replace all hardcoded font-family: monospace with var(--font-mono)
- Replace hardcoded 'Segoe UI' stack with var(--font-body)

4.2 Shadow Elevation System:
- Add --shadow-2xl, --shadow-card/dropdown/modal/toast/header/dark-lg tokens
- Replace hardcoded shadows in header, menu, banner, shared, recipe-modal,
  progress-panel, import-modal, alphabet-bar with semantic tokens
- Add dark theme shadow overrides with increased opacity

4.3 Transitions & Micro-interactions:
- Replace transition: all with specified properties (performance)
- Use --transition-fast/base/slow tokens instead of hardcoded 0.2s/0.3s
- Add :active scale feedback to modal buttons
- Enhance card hover with box-shadow + border-color lift

4.4 Dark Theme Refinement:
- Elevated shadow opacity for dark theme visibility

4.5 Density:
- Standardize container padding with --space-2 token

21 files changed

static/css/components/modal/_base.css

@@ -75,7 +75,14 @@ body.modal-open {
     font-weight: 500;
     font-size: 0.95em;
     min-width: 100px;
-    transition: background-color 0.2s, opacity 0.2s;
+    transition: background-color var(--transition-base), opacity var(--transition-base), transform var(--transition-fast);
+}
+
+.cancel-btn:active,
+.delete-btn:active,
+.exclude-btn:active,
+.confirm-btn:active {
+    transform: scale(0.98);
 }
 
 .cancel-btn {
@@ -128,7 +135,7 @@ body.modal-open {
     font-size: 1.5em;
     cursor: pointer;
     opacity: 0.7;
-    transition: opacity 0.2s;
+    transition: opacity var(--transition-base);
     z-index: 10;
 }