diff --git a/__test__/features/Calendars/CalendarAPI.test.tsx b/__test__/features/Calendars/CalendarAPI.test.tsx
index 2c584a2..1acec9a 100644
--- a/__test__/features/Calendars/CalendarAPI.test.tsx
+++ b/__test__/features/Calendars/CalendarAPI.test.tsx
@@ -82,7 +82,7 @@ describe("Calendar API", () => {
   it("patch Calendar", async () => {
     const calId = "calId";
     const calLink = "/calendars/calId.json";
-    const color = "calId";
+    const color = { light: "calIdLight", dark: "calIdDark" };
     const name = "new cal";
     const desc = "desc";
 
@@ -96,7 +96,7 @@ describe("Calendar API", () => {
       body: JSON.stringify({
         "dav:name": "new cal",
         "caldav:description": "desc",
-        "apple:color": "calId",
+        "apple:color": "calIdLight",
       }),
     });
   });
diff --git a/package-lock.json b/package-lock.json
index 98c863a..bcd0400 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -31,6 +31,7 @@
         "moment-timezone": "^0.5.48",
         "openid-client": "^6.5.3",
         "react": "^19.1.0",
+        "react-colorful": "^5.6.1",
         "react-dom": "^19.1.0",
         "react-i18next": "^13.5.0",
         "react-redux": "^9.2.0",
@@ -11795,6 +11796,16 @@
         "node": ">=0.10.0"
       }
     },
+    "node_modules/react-colorful": {
+      "version": "5.6.1",
+      "resolved": "https://registry.npmjs.org/react-colorful/-/react-colorful-5.6.1.tgz",
+      "integrity": "sha512-1exovf0uGTGyq5mXQT0zgQ80uvj2PCwvF8zY1RN9/vbJVSjSo3fsB/4L3ObbF7u70NduSiK4xu4Y6q1MHoUGEw==",
+      "license": "MIT",
+      "peerDependencies": {
+        "react": ">=16.8.0",
+        "react-dom": ">=16.8.0"
+      }
+    },
     "node_modules/react-dom": {
       "version": "19.1.0",
       "license": "MIT",
diff --git a/package.json b/package.json
index df091cb..09bbd5b 100644
--- a/package.json
+++ b/package.json
@@ -26,6 +26,7 @@
     "moment-timezone": "^0.5.48",
     "openid-client": "^6.5.3",
     "react": "^19.1.0",
+    "react-colorful": "^5.6.1",
     "react-dom": "^19.1.0",
     "react-i18next": "^13.5.0",
     "react-redux": "^9.2.0",
diff --git a/src/components/Attendees/PeopleSearch.tsx b/src/components/Attendees/PeopleSearch.tsx
index ea5481d..4b244e2 100644
--- a/src/components/Attendees/PeopleSearch.tsx
+++ b/src/components/Attendees/PeopleSearch.tsx
@@ -10,13 +10,14 @@ import { searchUsers } from "../../features/User/userAPI";
 import PeopleOutlineOutlinedIcon from "@mui/icons-material/PeopleOutlineOutlined";
 import Chip from "@mui/material/Chip";
 import { useTheme } from "@mui/material/styles";
+import { getAccessiblePair } from "../Calendar/utils/calendarColorsUtils";
 
 export interface User {
   email: string;
   displayName: string;
   avatarUrl: string;
   openpaasId: string;
-  color?: string;
+  color?: Record<string, string>;
 }
 
 export function PeopleSearch({
@@ -150,8 +151,8 @@ export function PeopleSearch({
           const label = isString ? option : option.displayName || option.email;
           const chipColor = isString
             ? theme.palette.grey[300]
-            : (option.color ?? theme.palette.grey[300]);
-          const textColor = theme.palette.getContrastText(chipColor);
+            : (option.color?.light ?? theme.palette.grey[300]);
+          const textColor = getAccessiblePair(chipColor, theme);
 
           return (
             <Chip
diff --git a/src/components/Calendar/Calendar.tsx b/src/components/Calendar/Calendar.tsx
index 9b1f953..0aecbbe 100644
--- a/src/components/Calendar/Calendar.tsx
+++ b/src/components/Calendar/Calendar.tsx
@@ -40,6 +40,8 @@ import momentTimezonePlugin from "@fullcalendar/moment-timezone";
 import { TimezoneSelector } from "./TimezoneSelector";
 import { MiniCalendar } from "./MiniCalendar";
 import { User } from "../Attendees/PeopleSearch";
+import { useTheme } from "@mui/material/styles";
+import { updateDarkColor } from "./utils/calendarColorsUtils";
 
 interface CalendarAppProps {
   calendarRef: React.RefObject<CalendarApi | null>;
@@ -58,7 +60,7 @@ export default function CalendarApp({
   const userId =
     useAppSelector((state) => state.user.userData?.openpaasId) ?? "";
   const dispatch = useAppDispatch();
-
+  const theme = useTheme();
   useEffect(() => {
     if (!tokens || !userId) {
       dispatch(push("/"));
@@ -108,6 +110,15 @@ export default function CalendarApp({
     }
   }, [calendars, userId]);
 
+  useEffect(() => {
+    updateDarkColor(calendars, theme, dispatch);
+  }, [
+    theme,
+    Object.values(calendars)
+      .map((c) => c.color?.dark)
+      .join(","),
+  ]);
+
   useEffect(() => {
     const validCalendarIds = new Set(Object.keys(calendars));
     setSelectedCalendars((prev) =>
diff --git a/src/components/Calendar/CalendarColorPicker.tsx b/src/components/Calendar/CalendarColorPicker.tsx
index 6d901f2..e80fcc0 100644
--- a/src/components/Calendar/CalendarColorPicker.tsx
+++ b/src/components/Calendar/CalendarColorPicker.tsx
@@ -1,36 +1,241 @@
-import { Box } from "@mui/material";
-
-const defaultColors = ["#34d399", "#fbbf24", "#f87171", "#60a5fa", "#f472b6"];
+import AddIcon from "@mui/icons-material/Add";
+import CheckIcon from "@mui/icons-material/Check";
+import {
+  Box,
+  Button,
+  Popover,
+  TextField,
+  Typography,
+  useTheme,
+} from "@mui/material";
+import { useState } from "react";
+import { HexColorPicker } from "react-colorful";
+import { defaultColors, getAccessiblePair } from "./utils/calendarColorsUtils";
 
 export function ColorPicker({
   selectedColor,
   colors = defaultColors,
   onChange,
 }: {
-  selectedColor?: string;
-  colors?: string[];
-  onChange: (color: string) => void;
+  selectedColor: Record<string, string>;
+  colors?: Record<string, string>[];
+  onChange: (color: Record<string, string>) => void;
 }) {
+  const [customColor, setCustomColor] = useState(
+    !colors.find((c) => c.light === selectedColor?.light)
+      ? selectedColor
+      : undefined
+  );
   return (
     <Box display="flex" alignItems="center" gap={1}>
       {colors.map((c) => (
-        <Box
-          key={c}
-          role="button"
-          aria-label={`select color ${c}`}
-          onClick={() => onChange(c)}
-          style={{
-            width: 20,
-            height: 20,
-            borderRadius: "50%",
-            backgroundColor: c,
-            cursor: "pointer",
-            border:
-              selectedColor === c ? "2px solid black" : "2px solid transparent",
-            transition: "all 0.2s",
-          }}
+        <ColorBox
+          key={c.light}
+          color={c}
+          onChange={onChange}
+          selectedColor={selectedColor}
         />
       ))}
+      {customColor && (
+        <ColorBox
+          color={customColor ?? {}}
+          onChange={onChange}
+          selectedColor={selectedColor}
+        />
+      )}
+
+      <ColorPickerBox
+        onChange={(c) => {
+          onChange(c);
+          setCustomColor(c);
+        }}
+        selectedColor={selectedColor}
+      />
     </Box>
   );
 }
+function ColorBox({
+  color,
+  onChange,
+  selectedColor,
+}: {
+  color: Record<string, string>;
+  onChange: (color: Record<string, string>) => void;
+  selectedColor: Record<string, string>;
+}) {
+  return (
+    <Box
+      role="button"
+      aria-label={`select color ${color.light}`}
+      onClick={() => onChange(color)}
+      style={{
+        width: "46px",
+        height: "32px",
+        padding: 0,
+        borderRadius: "4px",
+        backgroundColor: color.light,
+        cursor: "pointer",
+        transition: "all 0.2s",
+        display: "flex",
+        flexDirection: "column",
+        alignItems: "center",
+      }}
+    >
+      <Box
+        style={{
+          height: "7px",
+          width: "100%",
+          borderRadius: "4px 4px 0px 0px",
+          backgroundColor: color.dark,
+        }}
+      ></Box>
+      <CheckIcon
+        style={{
+          visibility:
+            selectedColor?.light === color.light ? "visible" : "hidden",
+          color: color.dark,
+        }}
+      />
+    </Box>
+  );
+}
+
+function ColorPickerBox({
+  onChange,
+  selectedColor,
+}: {
+  onChange: (color: Record<string, string>) => void;
+  selectedColor: Record<string, string>;
+}) {
+  const [oldColor] = useState(
+    selectedColor ?? { light: "#ffffff", dark: "#808080" }
+  );
+  const [color, setColor] = useState(oldColor);
+
+  const [anchorEl, setAnchorEl] = useState<HTMLButtonElement | null>(null);
+  const open = Boolean(anchorEl);
+  const theme = useTheme();
+
+  const handleClick = (event: any) => {
+    setAnchorEl(event.currentTarget);
+  };
+
+  const handleClose = () => {
+    onChange(oldColor);
+    setAnchorEl(null);
+  };
+
+  const handleSave = () => {
+    onChange(color);
+    setAnchorEl(null);
+  };
+
+  const handleColorChange = (c: string) => {
+    const newLight = c;
+    const newColor = {
+      light: newLight,
+      dark: getAccessiblePair(newLight, theme),
+    };
+    setColor(newColor);
+    onChange(newColor);
+  };
+  return (
+    <>
+      <Box
+        key={"colorPicker"}
+        role="button"
+        aria-label={`select custom color`}
+        onClick={handleClick}
+        style={{
+          width: "46px",
+          height: "32px",
+          padding: 0,
+          borderRadius: "4px",
+          border: "1px solid #CBD2E0",
+          backgroundColor: "#FFF",
+          cursor: "pointer",
+          transition: "all 0.2s",
+          display: "flex",
+          flexDirection: "column",
+          alignItems: "center",
+        }}
+      >
+        <Box
+          style={{
+            height: "7px",
+            width: "100%",
+            borderRadius: "4px 4px 0px 0px",
+            backgroundColor: "#CBD2E0",
+          }}
+        ></Box>
+        <AddIcon
+          style={{
+            color: "#CBD2E0",
+          }}
+        />
+      </Box>
+      <Popover
+        open={open}
+        anchorEl={anchorEl}
+        onClose={handleClose}
+        anchorOrigin={{
+          vertical: "center",
+          horizontal: "center",
+        }}
+        transformOrigin={{
+          vertical: "top",
+          horizontal: "left",
+        }}
+        slotProps={{
+          paper: {
+            style: {
+              padding: "24px",
+              width: "294px",
+              borderRadius: "8px",
+              boxShadow: "0px 1px 3px #3C404326",
+            },
+          },
+        }}
+      >
+        <Typography variant="subtitle1" fontWeight="600">
+          Choose custom colour
+        </Typography>
+        <Typography variant="body2" sx={{ mb: 2, color: "text.secondary" }}>
+          Choose a background colour for this calendar
+        </Typography>
+
+        <Box sx={{ mb: 2 }}>
+          <HexColorPicker
+            color={color.light}
+            onChange={handleColorChange}
+            style={{ width: "100%" }}
+          />
+        </Box>
+
+        <Box sx={{ display: "flex", alignItems: "center", mb: 2 }}>
+          <Typography variant="body2" sx={{ mr: 1 }}>
+            Hex
+          </Typography>
+          <TextField
+            value={color.light?.toUpperCase()}
+            onChange={(e) => handleColorChange(e.target.value)}
+            variant="standard"
+            size="small"
+            slotProps={{ inputLabel: { shrink: true } }}
+          />
+        </Box>
+
+        <Box sx={{ display: "flex", justifyContent: "flex-end", gap: 1 }}>
+          <Button onClick={handleClose}>Cancel</Button>
+          <Button
+            variant="contained"
+            onClick={handleSave}
+            sx={{ textTransform: "none" }}
+          >
+            Save
+          </Button>
+        </Box>
+      </Popover>
+    </>
+  );
+}
diff --git a/src/components/Calendar/CalendarModal.tsx b/src/components/Calendar/CalendarModal.tsx
index fc4e528..97fffbb 100644
--- a/src/components/Calendar/CalendarModal.tsx
+++ b/src/components/Calendar/CalendarModal.tsx
@@ -12,6 +12,7 @@ import { ResponsiveDialog } from "../Dialog";
 import { AccessTab } from "./AccessTab";
 import { ImportTab } from "./ImportTab";
 import { SettingsTab } from "./SettingsTab";
+import { defaultColors } from "./utils/calendarColorsUtils";
 
 function CalendarPopover({
   open,
@@ -34,7 +35,7 @@ function CalendarPopover({
   // existing calendar params
   const [name, setName] = useState("");
   const [description, setDescription] = useState("");
-  const [color, setColor] = useState("");
+  const [color, setColor] = useState<Record<string, string>>(defaultColors[0]);
   const [visibility, setVisibility] = useState<"private" | "public">("public");
 
   // import tab state
@@ -45,7 +46,7 @@ function CalendarPopover({
   // new calendar params (for import new)
   const [newCalName, setNewCalName] = useState("");
   const [newCalDescription, setNewCalDescription] = useState("");
-  const [newCalColor, setNewCalColor] = useState("");
+  const [newCalColor, setNewCalColor] = useState(defaultColors[0]);
   const [newCalVisibility, setNewCalVisibility] = useState<
     "public" | "private"
   >("public");
@@ -55,13 +56,13 @@ function CalendarPopover({
     if (calendar) {
       setName(calendar.name);
       setDescription(calendar.description ?? "");
-      setColor(calendar.color ?? "");
+      setColor(calendar.color ?? defaultColors[0]);
       setVisibility(calendar.visibility ?? "public");
       setImportTarget(calendar.id ?? "new");
     } else {
       setName("");
       setDescription("");
-      setColor("");
+      setColor(defaultColors[0]);
       setVisibility("public");
       setImportTarget("new");
     }
@@ -90,7 +91,7 @@ function CalendarPopover({
     calId: string,
     name: string,
     desc: string,
-    color: string,
+    color: Record<string, string>,
     visibility: string
   ) => {
     await dispatch(
@@ -160,7 +161,7 @@ function CalendarPopover({
     onClose(e, reason);
     setName("");
     setDescription("");
-    setColor("");
+    setColor(defaultColors[0]);
     setTab("settings");
     setVisibility("public");
     setImportTarget("new");
@@ -168,7 +169,7 @@ function CalendarPopover({
 
     setNewCalName("");
     setNewCalDescription("");
-    setNewCalColor("");
+    setNewCalColor(defaultColors[0]);
     setNewCalVisibility("public");
   };
 
diff --git a/src/components/Calendar/CalendarSearch.tsx b/src/components/Calendar/CalendarSearch.tsx
index b1d4d1e..97db2e8 100644
--- a/src/components/Calendar/CalendarSearch.tsx
+++ b/src/components/Calendar/CalendarSearch.tsx
@@ -16,6 +16,9 @@ import { addSharedCalendarAsync } from "../../features/Calendars/CalendarSlice";
 import { ColorPicker } from "./CalendarColorPicker";
 import { Calendars } from "../../features/Calendars/CalendarTypes";
 import { User, PeopleSearch } from "../Attendees/PeopleSearch";
+import { getAccessiblePair } from "./utils/calendarColorsUtils";
+import { useTheme } from "@mui/material/styles";
+import { ResponsiveDialog } from "../Dialog";
 
 interface CalendarWithOwner {
   cal: Record<string, any>;
@@ -29,8 +32,10 @@ function CalendarItem({
 }: {
   cal: CalendarWithOwner;
   onRemove: () => void;
-  onColorChange: (color: string) => void;
+  onColorChange: (color: Record<string, string>) => void;
 }) {
+  const theme = useTheme();
+
   return (
     <Box
       key={cal.owner.email + cal.cal["dav:name"]}
@@ -65,7 +70,10 @@ function CalendarItem({
 
       <Box display="flex" alignItems="center" gap={1}>
         <ColorPicker
-          selectedColor={cal.cal["apple:color"]}
+          selectedColor={{
+            light: cal.cal["apple:color"],
+            dark: getAccessiblePair(cal.cal["apple:color"], theme),
+          }}
           onChange={onColorChange}
         />
         <IconButton size="small" onClick={onRemove}>
@@ -85,7 +93,10 @@ function SelectedCalendarsList({
   calendars: Record<string, Calendars>;
   selectedCal: CalendarWithOwner[];
   onRemove: (cal: CalendarWithOwner) => void;
-  onColorChange: (cal: CalendarWithOwner, color: string) => void;
+  onColorChange: (
+    cal: CalendarWithOwner,
+    color: Record<string, string>
+  ) => void;
 }) {
   if (selectedCal.length === 0) return null;
 
@@ -194,7 +205,13 @@ export default function CalendarSearch({
               addSharedCalendarAsync({
                 userId: openpaasId,
                 calId,
-                cal: { ...cal, color: cal.cal["apple:color"] },
+                cal: {
+                  ...cal,
+                  color: {
+                    light: cal.cal["apple:color"],
+                    dark: cal.cal["X-TWAKE-Dark-theme-color"],
+                  },
+                },
               })
             );
             return cal.cal._links.self.href
@@ -212,122 +229,92 @@ export default function CalendarSearch({
   };
 
   return (
-    <Modal
+    <ResponsiveDialog
       open={open}
+      contentSx={{ paddingTop: "8px !important" }}
       onClose={() => {
         onClose({}, "backdropClick");
         setSelectedCalendars([]);
         setSelectedUsers([]);
       }}
+      title="Browse other calendars"
+      actions={
+        <>
+          <Button
+            variant="outlined"
+            onClick={() => onClose({}, "backdropClick")}
+          >
+            Cancel
+          </Button>
+          <Button variant="contained" onClick={handleSave}>
+            Add
+          </Button>
+        </>
+      }
     >
-      <Box
-        style={{
-          position: "absolute",
-          left: "50%",
-          top: "20%",
-          transform: "translate( -50%)",
-          width: "50vw",
-          maxHeight: "80vh",
+      <PeopleSearch
+        objectTypes={["user"]}
+        selectedUsers={selectedUsers}
+        onChange={async (event: any, value: User[]) => {
+          setSelectedUsers(value);
+
+          const cals = await Promise.all(
+            value.map(async (user: User) => {
+              const cals = (await getCalendars(
+                user.openpaasId,
+                "sharedPublic=true&withRights=true"
+              )) as Record<string, any>;
+              return cals._embedded?.["dav:calendar"]
+                ? cals._embedded["dav:calendar"].map(
+                    (cal: Record<string, any>) => ({ cal, owner: user })
+                  )
+                : { cal: undefined, owner: user };
+            })
+          );
+
+          setSelectedCalendars(cals.flat());
         }}
-      >
-        <Card
-          style={{
-            padding: 16,
-            borderRadius: 12,
-            boxShadow: "0 4px 12px rgba(0,0,0,0.15)",
-            display: "flex",
-            flexDirection: "column",
-            maxHeight: "80vh",
-          }}
-        >
-          <Box style={{ position: "absolute", top: 8, right: 8 }}>
-            <IconButton
-              size="small"
-              onClick={() => onClose({}, "backdropClick")}
-            >
-              <CloseIcon fontSize="small" />
-            </IconButton>
-          </Box>
+      />
 
-          <CardHeader
-            title="Browse other calendars"
-            style={{ paddingBottom: 0 }}
-          />
-          <CardContent style={{ flex: 1, overflow: "auto" }}>
-            <PeopleSearch
-              objectTypes={["user"]}
-              selectedUsers={selectedUsers}
-              onChange={async (event: any, value: User[]) => {
-                setSelectedUsers(value);
-
-                const cals = await Promise.all(
-                  value.map(async (user: User) => {
-                    const cals = (await getCalendars(
-                      user.openpaasId,
-                      "sharedPublic=true&withRights=true"
-                    )) as Record<string, any>;
-                    return cals._embedded?.["dav:calendar"]
-                      ? cals._embedded["dav:calendar"].map(
-                          (cal: Record<string, any>) => ({ cal, owner: user })
-                        )
-                      : { cal: undefined, owner: user };
-                  })
-                );
-
-                setSelectedCalendars(cals.flat());
-              }}
-            />
-
-            <SelectedCalendarsList
-              calendars={calendars}
-              selectedCal={selectedCal}
-              onRemove={(cal) => {
-                setSelectedCalendars((prev) =>
-                  prev.filter(
-                    (c) => c.cal._links.self.href !== cal.cal._links.self.href
-                  )
-                );
-                if (
-                  !selectedCal.find(
-                    (c) =>
-                      cal.owner.email === c.owner.email &&
-                      c.cal._links.self.href !== cal.cal._links.self.href
-                  )
-                ) {
-                  setSelectedUsers((prev) =>
-                    prev.filter((u) => u.email !== cal.owner.email)
-                  );
-                }
-              }}
-              onColorChange={(cal, color) =>
-                setSelectedCalendars((prev) =>
-                  prev.map((prevcal) =>
-                    prevcal.owner.email === cal.owner.email &&
-                    prevcal.cal._links.self.href === cal.cal._links.self.href
-                      ? {
-                          ...prevcal,
-                          cal: { ...prevcal.cal, "apple:color": color },
-                        }
-                      : prevcal
-                  )
-                )
-              }
-            />
-          </CardContent>
-
-          <CardActions style={{ justifyContent: "flex-end", gap: 8 }}>
-            <Button
-              variant="outlined"
-              onClick={() => onClose({}, "backdropClick")}
-            >
-              Cancel
-            </Button>
-            <Button variant="contained" onClick={handleSave}>
-              Add
-            </Button>
-          </CardActions>
-        </Card>
-      </Box>
-    </Modal>
+      <SelectedCalendarsList
+        calendars={calendars}
+        selectedCal={selectedCal}
+        onRemove={(cal) => {
+          setSelectedCalendars((prev) =>
+            prev.filter(
+              (c) => c.cal._links.self.href !== cal.cal._links.self.href
+            )
+          );
+          if (
+            !selectedCal.find(
+              (c) =>
+                cal.owner.email === c.owner.email &&
+                c.cal._links.self.href !== cal.cal._links.self.href
+            )
+          ) {
+            setSelectedUsers((prev) =>
+              prev.filter((u) => u.email !== cal.owner.email)
+            );
+          }
+        }}
+        onColorChange={(cal, color) =>
+          setSelectedCalendars((prev) =>
+            prev.map((prevcal) =>
+              prevcal.owner.email === cal.owner.email &&
+              prevcal.cal._links.self.href === cal.cal._links.self.href
+                ? {
+                    ...prevcal,
+                    cal: {
+                      ...prevcal.cal,
+                      "apple:color": color.light,
+                      "X-TWAKE-Dark-theme-color": color.dark,
+                    },
+                  }
+                : prevcal
+            )
+          )
+        }
+      />
+    </ResponsiveDialog>
   );
 }
diff --git a/src/components/Calendar/CalendarSelection.tsx b/src/components/Calendar/CalendarSelection.tsx
index 7a43327..315084f 100644
--- a/src/components/Calendar/CalendarSelection.tsx
+++ b/src/components/Calendar/CalendarSelection.tsx
@@ -218,8 +218,8 @@ function CalendarSelector({
         <label>
           <Checkbox
             sx={{
-              color: calendars[id].color,
-              "&.Mui-checked": { color: calendars[id].color },
+              color: calendars[id].color?.light,
+              "&.Mui-checked": { color: calendars[id].color?.light },
             }}
             size="small"
             checked={selectedCalendars.includes(id)}
@@ -232,7 +232,14 @@ function CalendarSelector({
         </IconButton>
       </div>
       <Menu id={id} anchorEl={anchorEl} open={open} onClose={handleClose}>
-        <MenuItem onClick={() => setOpen()}>Modify</MenuItem>
+        <MenuItem
+          onClick={() => {
+            setOpen();
+            handleClose();
+          }}
+        >
+          Modify
+        </MenuItem>
         {!isDefault && <Divider />}
         {!isDefault && (
           <MenuItem onClick={() => setDeletePopupOpen(!deletePopupOpen)}>
diff --git a/src/components/Calendar/ImportTab.tsx b/src/components/Calendar/ImportTab.tsx
index b7faa82..7ce2d8a 100644
--- a/src/components/Calendar/ImportTab.tsx
+++ b/src/components/Calendar/ImportTab.tsx
@@ -30,7 +30,7 @@ export function ImportTab({
     setName: Function;
     description: string;
     setDescription: Function;
-    color: string;
+    color: Record<string, string>;
     setColor: Function;
     visibility: "public" | "private";
     setVisibility: Function;
diff --git a/src/components/Calendar/SettingsTab.tsx b/src/components/Calendar/SettingsTab.tsx
index 27e81db..e89a5dc 100644
--- a/src/components/Calendar/SettingsTab.tsx
+++ b/src/components/Calendar/SettingsTab.tsx
@@ -29,7 +29,7 @@ export function SettingsTab({
   setName: Function;
   description: string;
   setDescription: Function;
-  color: string;
+  color: Record<string, string>;
   setColor: Function;
   visibility: "public" | "private";
   setVisibility: Function;
diff --git a/src/components/Calendar/TempCalendarsInput.tsx b/src/components/Calendar/TempCalendarsInput.tsx
index a675ed1..4de574d 100644
--- a/src/components/Calendar/TempCalendarsInput.tsx
+++ b/src/components/Calendar/TempCalendarsInput.tsx
@@ -1,3 +1,4 @@
+import { useTheme } from "@mui/material/styles";
 import { useRef } from "react";
 import { useAppDispatch, useAppSelector } from "../../app/hooks";
 import {
@@ -6,6 +7,7 @@ import {
 } from "../../features/Calendars/CalendarSlice";
 import { Calendars } from "../../features/Calendars/CalendarTypes";
 import { User, PeopleSearch } from "../Attendees/PeopleSearch";
+import { getAccessiblePair } from "./utils/calendarColorsUtils";
 
 const requestControllers = new Map<string, AbortController>();
 
@@ -26,6 +28,7 @@ export function TempCalendarsInput({
   const tempcalendars =
     useAppSelector((state) => state.calendars.templist) ?? {};
   const calendars = useAppSelector((state) => state.calendars.list);
+  const theme = useTheme();
 
   const prevUsersRef = useRef<User[]>([]);
   const userColors = new Map<string, string>();
@@ -59,8 +62,12 @@ export function TempCalendarsInput({
           const existingColors = new Set(userColors.values());
           userColors.set(user.email, generateUserColor(existingColors));
         }
+        const lightColor = userColors.get(user.email)!;
 
-        user.color = userColors.get(user.email)!;
+        user.color = {
+          light: lightColor,
+          dark: getAccessiblePair(lightColor, theme),
+        };
 
         dispatch(
           getTempCalendarsListAsync(user, { signal: controller.signal })
diff --git a/src/components/Calendar/handlers/viewHandlers.ts b/src/components/Calendar/handlers/viewHandlers.ts
index 1a27a6d..94e4948 100644
--- a/src/components/Calendar/handlers/viewHandlers.ts
+++ b/src/components/Calendar/handlers/viewHandlers.ts
@@ -127,7 +127,9 @@ export const createViewHandlers = (props: ViewHandlersProps) => {
       );
       const delegated = calendar.delegated;
       let Icon = null;
-      let titleStyle: React.CSSProperties = {};
+      let titleStyle: React.CSSProperties = {
+        color: event._def.extendedProps.colors?.dark,
+      };
 
       const showSpecialDisplay = attendees.filter((att: userAttendee) =>
         ownerEmails.has(att.cal_address.toLowerCase())
@@ -265,7 +267,7 @@ function RenderEventTitle(
         display: "flex",
         alignItems: "center",
         justifyContent: "center",
-        backgroundColor: calendar.color,
+        backgroundColor: calendar.color?.light,
         color: "white",
         borderRadius: "4px",
         border: "1px",
diff --git a/src/components/Calendar/utils/calendarColorsUtils.tsx b/src/components/Calendar/utils/calendarColorsUtils.tsx
new file mode 100644
index 0000000..c039e41
--- /dev/null
+++ b/src/components/Calendar/utils/calendarColorsUtils.tsx
@@ -0,0 +1,55 @@
+import { darken, getContrastRatio, lighten, Theme } from "@mui/material";
+import { ThunkDispatch } from "@reduxjs/toolkit";
+import { updateCalColor } from "../../../features/Calendars/CalendarSlice";
+import { Calendars } from "../../../features/Calendars/CalendarTypes";
+
+export function updateDarkColor(
+  calendars: Record<string, Calendars>,
+  theme: Theme,
+  dispatch: ThunkDispatch<any, any, any>
+) {
+  Object.values(calendars).forEach((cal) => {
+    if (!cal?.color?.light) return;
+    const baseColor = cal.color.light;
+
+    const isDefault = Object.values(defaultColors).find(
+      (c) => c.light === baseColor
+    );
+    const darkColor = isDefault
+      ? isDefault.dark
+      : getAccessiblePair(baseColor, theme);
+
+    dispatch(
+      updateCalColor({
+        id: cal.id,
+        color: { light: baseColor, dark: darkColor },
+      })
+    );
+  });
+}
+
+export function getAccessiblePair(baseColor: string, theme: Theme): string {
+  const contrastToBlack = getContrastRatio(baseColor, "#000");
+  const contrastToWhite = getContrastRatio(baseColor, "#fff");
+  const isLight = contrastToBlack > contrastToWhite;
+
+  const adjusted = isLight ? darken(baseColor, 0.6) : lighten(baseColor, 0.7);
+
+  // Check if contrast meets 4.5
+  const contrast = getContrastRatio(baseColor, adjusted);
+  console.log(isLight, contrast);
+  if (contrast >= 4.5) return adjusted;
+
+  if (isLight) {
+    return "#ffffffff";
+  }
+
+  return theme.palette.getContrastText(baseColor);
+}
+
+export const defaultColors = [
+  { light: "#D0ECDA", dark: "#329655" },
+  { light: "#FAE3CE", dark: "#E15300" },
+  { light: "#F5CFD0", dark: "#BE0103" },
+  { light: "#AFCBEF", dark: "#0654B1" },
+];
diff --git a/src/components/Calendar/utils/calendarUtils.ts b/src/components/Calendar/utils/calendarUtils.ts
index f20cf79..541b5fd 100644
--- a/src/components/Calendar/utils/calendarUtils.ts
+++ b/src/components/Calendar/utils/calendarUtils.ts
@@ -62,9 +62,9 @@ export const eventToFullCalendarFormat = (
     .concat(filteredTempEvents.map((e) => ({ ...e, temp: true })))
     .map((e) => {
       if (e.calId.split("/")[0] === userId) {
-        return { ...e, editable: true };
+        return { ...e, colors: e.color, color: e.color?.light, editable: true };
       }
-      return { ...e, editable: false };
+      return { ...e, colors: e.color, color: e.color?.light, editable: false };
     });
 };
 
diff --git a/src/features/Calendars/CalendarApi.ts b/src/features/Calendars/CalendarApi.ts
index 849920e..3eb6e7d 100644
--- a/src/features/Calendars/CalendarApi.ts
+++ b/src/features/Calendars/CalendarApi.ts
@@ -34,7 +34,7 @@ export async function getCalendar(
 export async function postCalendar(
   userId: string,
   calId: string,
-  color: string,
+  color: Record<string, string>,
   name: string,
   desc: string
 ) {
@@ -67,7 +67,10 @@ export async function addSharedCalendar(
       "calendarserver:source": {
         acl: cal.cal.acl,
         calendarHomeId: cal.cal.id,
-        color: cal.cal["apple:color"],
+        color: {
+          light: cal.cal["apple:color"],
+          dark: cal.cal["X-TWAKE-Dark-theme-color"],
+        },
         description: cal.cal["caldav:description"],
         href: cal.cal._links.self.href,
         id: cal.cal.id,
@@ -81,7 +84,7 @@ export async function addSharedCalendar(
 
 export async function proppatchCalendar(
   calLink: string,
-  patch: { name: string; desc: string; color: string }
+  patch: { name: string; desc: string; color: Record<string, string> }
 ) {
   const body: Record<string, string> = {};
   if (patch.name) {
@@ -90,8 +93,8 @@ export async function proppatchCalendar(
   if (patch.desc) {
     body["caldav:description"] = patch.desc;
   }
-  if (patch.color) {
-    body["apple:color"] = patch.color;
+  if (patch.color.light) {
+    body["apple:color"] = patch.color.light;
   }
   const response = await api(`dav${calLink}`, {
     method: "PROPPATCH",
diff --git a/src/features/Calendars/CalendarSlice.ts b/src/features/Calendars/CalendarSlice.ts
index 7239444..9ad5b6a 100644
--- a/src/features/Calendars/CalendarSlice.ts
+++ b/src/features/Calendars/CalendarSlice.ts
@@ -53,7 +53,10 @@ export const getCalendarsListAsync = createAsyncThunk<
     const id = source.replace("/calendars/", "").replace(".json", "");
     const visibility = getCalendarVisibility(cal["acl"]);
     const ownerData: any = await getUserDetails(id.split("/")[0]);
-    const color = cal["apple:color"];
+    const color = {
+      light: cal["apple:color"] ?? "#006BD8",
+      dark: cal["X-TWAKE-Dark-theme-color"] ?? "#FFF",
+    };
     importedCalendars[id] = {
       id,
       name,
@@ -106,7 +109,10 @@ export const getTempCalendarsListAsync = createAsyncThunk<
       ownerEmails: ownerData.emails,
       description,
       delegated,
-      color: tempUser.color ?? "#a8a8a8ff",
+      color: {
+        light: tempUser.color?.light ?? "#a8a8a8ff",
+        dark: tempUser.color?.dark ?? "#a8a8a8ff",
+      },
       visibility,
       events: {},
     };
@@ -157,7 +163,7 @@ export const putEventAsync = createAsyncThunk<
       return vevents.map((vevent: any[]) => {
         return parseCalendarEvent(
           vevent[1],
-          cal.color ?? "",
+          cal.color ?? {},
           cal.id,
           eventURL,
           valarm
@@ -187,12 +193,12 @@ export const patchCalendarAsync = createAsyncThunk<
   {
     calId: string;
     calLink: string;
-    patch: { name: string; desc: string; color: string };
+    patch: { name: string; desc: string; color: Record<string, string> };
   }, // Return type
   {
     calId: string;
     calLink: string;
-    patch: { name: string; desc: string; color: string };
+    patch: { name: string; desc: string; color: Record<string, string> };
   } // Arg type
 >("calendars/patchCalendar", async ({ calId, calLink, patch }) => {
   await proppatchCalendar(calLink, patch);
@@ -238,7 +244,7 @@ export const moveEventAsync = createAsyncThunk<
       const vevents = eventdata.data[2] as any[][];
       const eventURL = eventdata._links.self.href;
       return vevents.map((vevent: any[]) => {
-        return parseCalendarEvent(vevent[1], cal.color ?? "", cal.id, eventURL);
+        return parseCalendarEvent(vevent[1], cal.color ?? {}, cal.id, eventURL);
       });
     }
   );
@@ -304,13 +310,19 @@ export const createCalendarAsync = createAsyncThunk<
   {
     userId: string;
     calId: string;
-    color: string;
+    color: Record<string, string>;
     name: string;
     desc: string;
     owner: string;
     ownerEmails: string[];
   }, // Return type
-  { userId: string; calId: string; color: string; name: string; desc: string } // Arg type
+  {
+    userId: string;
+    calId: string;
+    color: Record<string, string>;
+    name: string;
+    desc: string;
+  } // Arg type
 >("calendars/createCalendar", async ({ userId, calId, color, name, desc }) => {
   await postCalendar(userId, calId, color, name, desc);
   const ownerData: any = await getUserDetails(userId.split("/")[0]);
@@ -331,7 +343,7 @@ export const createCalendarAsync = createAsyncThunk<
 export const addSharedCalendarAsync = createAsyncThunk<
   {
     calId: string;
-    color: string;
+    color: Record<string, string>;
     link: string;
     name: string;
     desc: string;
@@ -352,7 +364,10 @@ export const addSharedCalendarAsync = createAsyncThunk<
     calId: cal.cal._links.self.href
       .replace("/calendars/", "")
       .replace(".json", ""),
-    color: cal.cal["apple:color"],
+    color: {
+      light: cal.cal["apple:color"],
+      dark: "#000",
+    },
     link: `/calendars/${userId}/${calId}.json`,
     desc: cal.cal["caldav:description"],
     name: cal.cal["dav:name"],
@@ -388,12 +403,15 @@ const CalendarSlice = createSlice({
     timeZone: string;
   },
   reducers: {
-    createCalendar: (state, action: PayloadAction<Record<string, string>>) => {
+    createCalendar: (
+      state,
+      action: PayloadAction<Record<string, string | Record<string, string>>>
+    ) => {
       const id = Date.now().toString(36);
       state.list[id] = {} as Calendars;
-      state.list[id].name = action.payload.name;
-      state.list[id].color = action.payload.color;
-      state.list[id].description = action.payload.description;
+      state.list[id].name = action.payload.name as string;
+      state.list[id].color = action.payload.color as Record<string, string>;
+      state.list[id].description = action.payload.description as string;
       state.list[id].events = {};
     },
     addEvent: (
@@ -450,6 +468,15 @@ const CalendarSlice = createSlice({
       if (!state.list[action.payload]) return;
       state.list[action.payload].lastCacheCleared = Date.now();
     },
+    updateCalColor: (
+      state,
+      action: PayloadAction<{
+        id: string;
+        color: { light: string; dark: string };
+      }>
+    ) => {
+      state.list[action.payload.id].color = action.payload.color;
+    },
   },
   extraReducers: (builder) => {
     builder
@@ -719,5 +746,6 @@ export const {
   emptyEventsCal,
   setTimeZone,
   clearFetchCache,
+  updateCalColor,
 } = CalendarSlice.actions;
 export default CalendarSlice.reducer;
diff --git a/src/features/Calendars/CalendarTypes.ts b/src/features/Calendars/CalendarTypes.ts
index 7c9717a..2ecbc98 100644
--- a/src/features/Calendars/CalendarTypes.ts
+++ b/src/features/Calendars/CalendarTypes.ts
@@ -6,7 +6,7 @@ export interface Calendars {
   name: string;
   delegated?: boolean;
   prodid?: string;
-  color?: string;
+  color?: Record<string, string>;
   ownerEmails?: string[];
   owner: string;
   description?: string;
diff --git a/src/features/Events/EventApi.ts b/src/features/Events/EventApi.ts
index d018621..c4030b8 100644
--- a/src/features/Events/EventApi.ts
+++ b/src/features/Events/EventApi.ts
@@ -36,7 +36,7 @@ export async function getEvent(event: CalendarEvent, isMaster?: boolean) {
 
   const eventjson = parseCalendarEvent(
     targetVevent[1],
-    event.color ?? "",
+    event.color ?? {},
     event.calId,
     event.URL
   );
diff --git a/src/features/Events/EventDisplay.tsx b/src/features/Events/EventDisplay.tsx
index 5c2af34..9d6470d 100644
--- a/src/features/Events/EventDisplay.tsx
+++ b/src/features/Events/EventDisplay.tsx
@@ -48,6 +48,7 @@ import { userAttendee } from "../User/userDataTypes";
 import { getEvent } from "./EventApi";
 import { formatLocalDateTime } from "../../components/Event/EventFormFields";
 import { CalendarEvent, RepetitionObject } from "./EventsTypes";
+import { light } from "@mui/material/styles/createPalette";
 
 export default function EventDisplayModal({
   eventId,
@@ -224,7 +225,8 @@ export default function EventDisplayModal({
             <Typography variant="body2">
               <CircleIcon
                 style={{
-                  color: userPersonnalCalendars[index].color ?? "#3788D8",
+                  color:
+                    userPersonnalCalendars[index].color?.light ?? "#3788D8",
                   width: 12,
                   height: 12,
                 }}
@@ -238,7 +240,7 @@ export default function EventDisplayModal({
             <Typography variant="body2">
               <CircleIcon
                 style={{
-                  color: calendars[index].color ?? "#3788D8",
+                  color: calendars[index].color?.light ?? "#3788D8",
                   width: 12,
                   height: 12,
                 }}
diff --git a/src/features/Events/EventDisplayPreview.tsx b/src/features/Events/EventDisplayPreview.tsx
index 41c33b4..28b987f 100644
--- a/src/features/Events/EventDisplayPreview.tsx
+++ b/src/features/Events/EventDisplayPreview.tsx
@@ -577,7 +577,7 @@ export default function EventPreviewModal({
           <CalendarTodayIcon style={{ fontSize: 16 }} />
           <CircleIcon
             style={{
-              color: calendar.color ?? "#3788D8",
+              color: calendar.color?.light ?? "#3788D8",
               width: 12,
               height: 12,
             }}
diff --git a/src/features/Events/EventsTypes.ts b/src/features/Events/EventsTypes.ts
index 8cf8fd0..fa68998 100644
--- a/src/features/Events/EventsTypes.ts
+++ b/src/features/Events/EventsTypes.ts
@@ -17,7 +17,7 @@ export interface CalendarEvent {
   attendee: userAttendee[];
   stamp?: string;
   sequence?: Number;
-  color?: string;
+  color?: Record<string, string>;
   allday?: boolean;
   error?: string;
   status?: string;
diff --git a/src/features/Events/eventUtils.ts b/src/features/Events/eventUtils.ts
index bce2723..b2c340e 100644
--- a/src/features/Events/eventUtils.ts
+++ b/src/features/Events/eventUtils.ts
@@ -1,5 +1,5 @@
 import { userAttendee } from "../User/userDataTypes";
-import { AlarmObject, CalendarEvent } from "./EventsTypes";
+import { AlarmObject, CalendarEvent, RepetitionObject } from "./EventsTypes";
 import ICAL from "ical.js";
 import { TIMEZONES } from "../../utils/timezone-data";
 import moment from "moment";
@@ -7,7 +7,7 @@ type RawEntry = [string, Record<string, string>, string, any];
 
 export function parseCalendarEvent(
   data: RawEntry[],
-  color: string,
+  color: Record<string, string>,
   calendarid: string,
   eventURL: string,
   valarm?: RawEntry[]