修复 BottomCard 深色模式适配和 DayCell 无障碍支持

shared/src/commonMain/kotlin/plus/rua/project/ui/BottomCard.kt

@@ -14,7 +14,6 @@ import androidx.compose.runtime.Composable
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
-import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.input.pointer.pointerInput
 import androidx.compose.ui.platform.LocalDensity
 import androidx.compose.ui.unit.dp
@@ -87,7 +86,7 @@ fun BottomCard(
                     .align(Alignment.TopCenter)
                     .padding(top = 8.dp, bottom = 8.dp)
                     .clip(RoundedCornerShape(2.dp))
-                    .background(Color.Gray.copy(alpha = 0.4f))
+                    .background(MaterialTheme.colorScheme.onSurfaceVariant.copy(alpha = 0.4f))
                     .fillMaxWidth(0.15f)
                     .height(4.dp)
             )

shared/src/commonMain/kotlin/plus/rua/project/ui/DayCell.kt

@@ -18,6 +18,8 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.draw.drawBehind
 import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.semantics.contentDescription
+import androidx.compose.ui.semantics.semantics
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.drawscope.Stroke
 import androidx.compose.ui.text.style.TextAlign
@@ -106,6 +108,10 @@ fun DayCell(
     Box(
         modifier = modifier
             .aspectRatio(1f)
+            .semantics {
+                @Suppress("DEPRECATION")
+                contentDescription = "${date.year}年${date.monthNumber}月${date.day}日"
+            }
             .clip(CircleShape)
             .drawBehind {
                 if (revealProgress > 0f) {