fix(dark-mode): fix Timeline, Calendar, and Slider theming

- Timeline: make head/dot-container bg transparent to eliminate grey
  column artifact; give dot circle a solid bg to mask the line
- Calendar: add calendar-bg, calendar-border, calendar-hover tokens
  to both light and dark themes (was falling back to hardcoded #fff)
- Slider: use var(--ty-color-primary) for thumb border so it follows
  runtime theme color changes from the color picker

Author: wangdicoder

components/slider/style/_index.scss

@@ -114,7 +114,7 @@
     box-sizing: border-box;
     width: 14px;
     height: 14px;
-    border: 1px solid var(--ty-slider-thumb-border);
+    border: 1px solid var(--ty-color-primary);
     background-color: var(--ty-slider-thumb-bg);
     border-radius: 50%;
     transition: transform 250ms;

components/style/themes/_dark.scss

@@ -372,4 +372,9 @@ $dark-theme: (
   cascader-dropdown-bg: #1f1f1f,
   cascader-hover: #2a2a2a,
   cascader-selected-bg: rgba(144, 101, 208, 0.1),
+
+  // ---- Component-specific: Calendar ----
+  calendar-bg: #1f1f1f,
+  calendar-border: #363636,
+  calendar-hover: #2a2a2a,
 );

components/style/themes/_light.scss

@@ -372,4 +372,9 @@ $light-theme: (
   cascader-dropdown-bg: #fff,
   cascader-hover: #f5f5f5,
   cascader-selected-bg: rgba(110, 65, 191, 0.06),
+
+  // ---- Component-specific: Calendar ----
+  calendar-bg: #fff,
+  calendar-border: #e9ecef,
+  calendar-hover: #f6f9fc,
 );

components/timeline/style/_index.scss

@@ -28,7 +28,7 @@
 
   &__head {
     width: 16px;
-    background-color: var(--ty-timeline-head-bg);
+    background-color: transparent;
     position: absolute;
     color: var(--ty-color-primary);
     height: 100%;
@@ -48,7 +48,7 @@
     position: absolute;
     left: 50%;
     transform: translateX(-50%);
-    background-color: var(--ty-timeline-dot-bg);
+    background-color: transparent;
   }
 
   &__dot {
@@ -57,6 +57,7 @@
     height: 10px;
     border: 2px solid var(--ty-color-primary);
     border-radius: 100px;
+    background-color: var(--ty-color-bg);
   }
 
   &__content {