Fix Undo icon and improve mobile UX

src/styles/main.css

@@ -1,3 +1,5 @@
+@import './scrollbar.css';
+
 :root {
   /* --- Glassmorphism Design System --- */
   --bg-gradient: linear-gradient(135deg, #43C6AC 0%, #191654 100%);
@@ -52,6 +54,9 @@
   --scroll-track: rgba(0, 0, 0, 0.1);
   --scroll-thumb: rgba(255, 255, 255, 0.2);
   --scroll-thumb-hover: var(--accent-cyan);
+  --fixed-bar-bg: rgba(0, 0, 0, 0.85);
+  --fixed-bar-thumb: rgba(0, 242, 255, 0.5);
+  --fixed-bar-thumb-hover: rgba(0, 242, 255, 0.8);
   
   /* Rozmiary */
   --cell-size: 30px;
@@ -113,6 +118,9 @@
   --scroll-track: rgba(15, 23, 42, 0.08);
   --scroll-thumb: rgba(15, 23, 42, 0.2);
   --scroll-thumb-hover: #0ea5e9;
+  --fixed-bar-bg: rgba(248, 250, 255, 0.95);
+  --fixed-bar-thumb: rgba(14, 165, 233, 0.5);
+  --fixed-bar-thumb-hover: rgba(14, 165, 233, 0.8);
 }
 
 * {

src/styles/scrollbar.css

@@ -0,0 +1,54 @@
+
+/* Fixed Scroll Bar */
+.fixed-scroll-bar {
+  position: fixed;
+  bottom: 15px;
+  left: 50%;
+  transform: translateX(-50%);
+  width: 85%;
+  max-width: 400px;
+  height: 44px; /* Increased hit area */
+  background: transparent;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  z-index: 1000;
+  opacity: 0;
+  animation: fadeIn 0.4s cubic-bezier(0.16, 1, 0.3, 1) forwards;
+  pointer-events: none;
+}
+
+@keyframes fadeIn {
+  from { opacity: 0; transform: translateX(-50%) translateY(10px); }
+  to { opacity: 1; transform: translateX(-50%) translateY(0); }
+}
+
+.fixed-scroll-track {
+  width: 100%;
+  height: 14px; /* Increased visual thickness */
+  background: rgba(15, 23, 42, 0.4);
+  backdrop-filter: blur(4px);
+  -webkit-backdrop-filter: blur(4px);
+  border-radius: 7px;
+  position: relative;
+  pointer-events: auto;
+  border: 1px solid rgba(255, 255, 255, 0.15);
+  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
+}
+
+.fixed-scroll-thumb {
+  position: absolute;
+  top: 0;
+  height: 100%;
+  background: var(--primary-accent);
+  border-radius: 7px;
+  cursor: grab;
+  box-shadow: 0 0 12px rgba(0, 242, 255, 0.5);
+  transition: background 0.2s ease, box-shadow 0.2s ease;
+}
+
+.fixed-scroll-thumb:active {
+  cursor: grabbing;
+  background: #fff;
+  box-shadow: 0 0 15px rgba(255, 255, 255, 0.6);
+}