Fixes #5: Refactor code quality - Part 1

- Split index.js from 1,567 lines to 456 lines (73% reduction)
  - Extracted settings event listeners to src/systems/ui/settingsListeners.js
  - Extracted settings panel to src/core/settingsPanel.js
  - Simplified initUI() and main initialization block

- Modularized style.css into 28 logical CSS modules in src/styles/
  - Added build script (npm run build:css) to concatenate modules
  - Modules: panel, components, user-stats, info-box, thoughts, settings,
    themes, modals, mobile, inventory, quests, equipment, encounters,
    weather, music-player, FAB widgets, strip widgets, etc.

- Updated package.json with build:css script and type: module

No functional changes - pure refactoring for maintainability.

src/styles/_20_plot-buttons.css

@@ -0,0 +1,132 @@
+/* ============================================
+   STATUS EFFECTS
+   ============================================ */
+
+/* Status Effects Container */
+.rpg-encounter-statuses {
+    display: flex;
+    flex-wrap: wrap;
+    gap: 4px;
+    margin-top: 8px;
+}
+
+/* Individual Status Effect */
+.rpg-encounter-status {
+    display: inline-block;
+    font-size: 20px;
+    line-height: 1;
+    padding: 4px;
+    background: rgba(0, 0, 0, 0.3);
+    border-radius: 4px;
+    cursor: help;
+    transition: transform 0.2s ease;
+}
+
+.rpg-encounter-status:hover {
+    transform: scale(1.2);
+}
+
+/* ============================================
+   PLOT BUTTONS - RESPONSIVE LAYOUT
+   ============================================ */
+
+/* Base styles for plot buttons container */
+#rpg-plot-buttons {
+    display: flex !important;
+    flex-wrap: wrap;
+    justify-content: center;
+    gap: 4px;
+    align-items: center;
+}
+
+/* Base button styles - ensure consistent sizing */
+#rpg-plot-random,
+#rpg-plot-natural,
+#rpg-encounter-button {
+    flex: 0 1 auto;
+    white-space: nowrap;
+    min-width: 0;
+}
+
+/* Tablet and smaller screens - adjust button sizing */
+@media (max-width: 768px) {
+    #rpg-plot-buttons {
+        gap: 3px;
+    }
+
+    #rpg-plot-random,
+    #rpg-plot-natural,
+    #rpg-encounter-button {
+        padding: 6px 10px !important;
+        font-size: 12px !important;
+    }
+}
+
+/* Small mobile screens - more compact buttons */
+@media (max-width: 600px) {
+    #rpg-plot-buttons {
+        gap: 2px;
+    }
+
+    #rpg-plot-random,
+    #rpg-plot-natural,
+    #rpg-encounter-button {
+        padding: 5px 8px !important;
+        font-size: 11px !important;
+    }
+}
+
+/* Very small screens - stack buttons vertically or use icons only */
+@media (max-width: 480px) {
+    #rpg-plot-buttons {
+        gap: 4px;
+    }
+
+    /* Option 1: Stack vertically (uncomment if preferred)
+    #rpg-plot-buttons {
+        flex-direction: column;
+        width: 100%;
+    }
+
+    #rpg-plot-random,
+    #rpg-plot-natural,
+    #rpg-encounter-button {
+        width: 100%;
+        padding: 8px !important;
+        font-size: 13px !important;
+    }
+    */
+
+    /* Option 2: Keep horizontal but more compact (default) */
+    #rpg-plot-random,
+    #rpg-plot-natural,
+    #rpg-encounter-button {
+        padding: 6px 8px !important;
+        font-size: 11px !important;
+    }
+}
+
+/* Extra small screens - icon-only mode */
+@media (max-width: 400px) {
+    #rpg-plot-random,
+    #rpg-plot-natural,
+    #rpg-encounter-button {
+        padding: 6px !important;
+    }
+
+    /* Hide button text, keep icons */
+    #rpg-plot-random .rpg-btn-text,
+    #rpg-plot-natural .rpg-btn-text,
+    #rpg-encounter-button .rpg-btn-text {
+        display: none;
+    }
+
+    /* Ensure icons are visible */
+    #rpg-plot-random i,
+    #rpg-plot-natural i,
+    #rpg-encounter-button i {
+        margin: 0 !important;
+        font-size: 14px;
+    }
+}
+