refactor(core): [CORE-23] complete keyboard controls and focus lifecycle

packages/artplayer/src/style/accessibility.less

@@ -0,0 +1,22 @@
+.art-video-player {
+  [tabindex]:focus-visible,
+  input:focus-visible,
+  button:focus-visible,
+  a:focus-visible {
+    outline: 2px solid currentColor;
+    outline-offset: -2px;
+  }
+
+  &.art-keyboard-focus :focus {
+    outline: 2px solid currentColor;
+    outline-offset: -2px;
+  }
+
+  &.art-keyboard-focus:not(.art-lock) .art-bottom {
+    opacity: 1;
+    .art-controls,
+    .art-progress {
+      transform: translateY(0);
+    }
+  }
+}