diff --git a/src/App.tsx b/src/App.tsx
index ce5f9b2..fa7b957 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -403,6 +403,13 @@ const TimelineSection = ({
   const actionsDisabled = timelineType === "notifications";
   const emptyMessage = timelineType === "notifications" ? "표시할 알림이 없습니다." : "표시할 글이 없습니다.";
 
+  useEffect(() => {
+    if (!timeline.error) {
+      return;
+    }
+    showToast(timeline.error, { tone: "error" });
+  }, [showToast, timeline.error]);
+
   useEffect(() => {
     const el = scrollRef.current;
     if (!el) {
@@ -475,6 +482,13 @@ const TimelineSection = ({
     refreshNotifications();
   }, [notificationsOpen, refreshNotifications]);
 
+  useEffect(() => {
+    if (!notificationsError) {
+      return;
+    }
+    showToast(notificationsError, { tone: "error" });
+  }, [notificationsError, showToast]);
+
   const handleToggleFavourite = async (status: Status) => {
     if (!account) {
       onError("계정을 선택해주세요.");
@@ -649,7 +663,6 @@ const TimelineSection = ({
                 <div className="overlay-backdrop" aria-hidden="true" />
                 <div ref={notificationMenuRef} className="notification-popover panel" role="dialog" aria-modal="true" aria-label="알림">
                   <div className="notification-popover-body" ref={notificationScrollRef}>
-                    {notificationsError ? <p className="error">{notificationsError}</p> : null}
                     {notificationItems.length === 0 && !notificationsLoading ? (
                       <p className="empty">표시할 알림이 없습니다.</p>
                     ) : null}
@@ -785,7 +798,6 @@ const TimelineSection = ({
       </div>
       <div className="timeline-column-body" ref={scrollRef}>
         {!account ? <p className="empty">계정을 선택하면 타임라인을 불러옵니다.</p> : null}
-        {account && timeline.error ? <p className="error">{timeline.error}</p> : null}
         {account && timeline.items.length === 0 && !timeline.loading ? (
           <p className="empty">{emptyMessage}</p>
         ) : null}
@@ -836,10 +848,14 @@ const TimelineSection = ({
   );
 };
 
-type ThemeMode = "default" | "christmas" | "sky-pink" | "monochrome";
+type ThemeMode = "default" | "christmas" | "sky-pink" | "monochrome" | "matcha-core";
 
 const isThemeMode = (value: string): value is ThemeMode =>
-  value === "default" || value === "christmas" || value === "sky-pink" || value === "monochrome";
+  value === "default" ||
+  value === "christmas" ||
+  value === "sky-pink" ||
+  value === "monochrome" ||
+  value === "matcha-core";
 
 const getStoredTheme = (): ThemeMode => {
   const storedTheme = localStorage.getItem("textodon.theme");
@@ -888,6 +904,7 @@ export const App = () => {
   const [mobileMenuOpen, setMobileMenuOpen] = useState(false);
   const [mobileComposeOpen, setMobileComposeOpen] = useState(false);
   const { services, accountsState } = useAppContext();
+  const { showToast } = useToast();
   const [sections, setSections] = useState<TimelineSectionConfig[]>(() => {
     try {
       const raw = localStorage.getItem(SECTION_STORAGE_KEY);
@@ -956,6 +973,14 @@ export const App = () => {
   const previousAccountIds = useRef<Set<string>>(new Set());
   const hasAccounts = accountsState.accounts.length > 0;
 
+  useEffect(() => {
+    if (!actionError) {
+      return;
+    }
+    showToast(actionError, { tone: "error" });
+    setActionError(null);
+  }, [actionError, showToast]);
+
   const registerTimelineListener = useCallback((accountId: string, listener: (status: Status) => void) => {
     const next = new Map(timelineListeners.current);
     const existing = next.get(accountId) ?? new Set();
@@ -1669,7 +1694,6 @@ export const App = () => {
         {hasAccounts ? (
           <section className="main-column">
             {oauthLoading ? <p className="empty">OAuth 인증 중...</p> : null}
-            {actionError ? <p className="error">{actionError}</p> : null}
             {route === "home" ? (
               <section className="panel">
                 {sections.length > 0 ? (
@@ -1881,6 +1905,7 @@ onAccountChange={setSectionAccount}
                 <option value="christmas">크리스마스</option>
                 <option value="sky-pink">하늘핑크</option>
                 <option value="monochrome">모노톤</option>
+                <option value="matcha-core">말차코어</option>
               </select>
             </div>
             <div className="settings-item">
diff --git a/src/ui/components/AccountAdd.tsx b/src/ui/components/AccountAdd.tsx
index 2e65c51..8b8ef7e 100644
--- a/src/ui/components/AccountAdd.tsx
+++ b/src/ui/components/AccountAdd.tsx
@@ -2,6 +2,7 @@ import React, { useState } from "react";
 import type { OAuthClient } from "../../services/OAuthClient";
 import { normalizeInstanceUrl } from "../utils/account";
 import { createOauthState, loadRegisteredApp, saveRegisteredApp, storePendingOAuth } from "../utils/oauth";
+import { useToast } from "../state/ToastContext";
 
 export const AccountAdd = ({
   oauth
@@ -9,16 +10,15 @@ export const AccountAdd = ({
   oauth: OAuthClient;
 }) => {
   const [instanceUrl, setInstanceUrl] = useState("");
-  const [error, setError] = useState<string | null>(null);
   const [loading, setLoading] = useState(false);
   const [showForm, setShowForm] = useState(false);
+  const { showToast } = useToast();
   const handleSubmit = async (event: React.FormEvent) => {
     event.preventDefault();
-    setError(null);
 
     const normalizedUrl = normalizeInstanceUrl(instanceUrl);
     if (!normalizedUrl) {
-      setError("서버 주소를 입력해주세요.");
+      showToast("서버 주소를 입력해주세요.", { tone: "error" });
       return;
     }
 
@@ -42,7 +42,7 @@ export const AccountAdd = ({
       const authorizeUrl = oauth.buildAuthorizeUrl(registered, state);
       window.location.assign(authorizeUrl);
     } catch (err) {
-      setError(err instanceof Error ? err.message : "OAuth 연결에 실패했습니다.");
+      showToast(err instanceof Error ? err.message : "OAuth 연결에 실패했습니다.", { tone: "error" });
     } finally {
       setLoading(false);
     }
@@ -83,7 +83,6 @@ export const AccountAdd = ({
                 onChange={(event) => setInstanceUrl(event.target.value)}
               />
             </label>
-            {error ? <p className="error">{error}</p> : null}
             <button type="submit" disabled={loading}>
               {loading ? "연결 중..." : "OAuth로 연결"}
             </button>
diff --git a/src/ui/components/ComposeBox.tsx b/src/ui/components/ComposeBox.tsx
index c3c71d5..b59472b 100644
--- a/src/ui/components/ComposeBox.tsx
+++ b/src/ui/components/ComposeBox.tsx
@@ -3,6 +3,7 @@ import type { Account, Visibility } from "../../domain/types";
 import type { MastodonApi } from "../../services/MastodonApi";
 import { useEmojiManager, type EmojiItem } from "../hooks/useEmojiManager";
 import { useImageZoom } from "../hooks/useImageZoom";
+import { useToast } from "../state/ToastContext";
 import {
   calculateCharacterCount,
   getCharacterLimit,
@@ -88,6 +89,8 @@ export const ComposeBox = ({
   } = useImageZoom(imageContainerRef, imageRef);
   const [emojiPanelOpen, setEmojiPanelOpen] = useState(false);
   const [recentOpen, setRecentOpen] = useState(true);
+  const { showToast } = useToast();
+  const lastEmojiErrorRef = useRef<string | null>(null);
 
   // 문자 수 관련 상태
   const [characterLimit, setCharacterLimit] = useState<number | null>(null);
@@ -108,6 +111,19 @@ export const ComposeBox = ({
     searchEmojis
   } = useEmojiManager(account, api, false);
 
+  useEffect(() => {
+    if (emojiStatus !== "error") {
+      lastEmojiErrorRef.current = null;
+      return;
+    }
+    const message = emojiError ?? "이모지를 불러오지 못했습니다.";
+    if (message === lastEmojiErrorRef.current) {
+      return;
+    }
+    lastEmojiErrorRef.current = message;
+    showToast(message, { tone: "error" });
+  }, [emojiError, emojiStatus, showToast]);
+
   const activeImage = useMemo(
     () => attachments.find((item) => item.id === activeImageId) ?? null,
     [attachments, activeImageId]
@@ -200,7 +216,7 @@ export const ComposeBox = ({
 
     // 문자 수 제한 검사
     if (characterLimit && currentCharCount > characterLimit) {
-      alert(`글자 수 제한(${characterLimit.toLocaleString()}자)을 초과했습니다.`);
+      showToast(`글자 수 제한(${characterLimit.toLocaleString()}자)을 초과했습니다.`, { tone: "error" });
       return;
     }
 
diff --git a/src/ui/components/ProfileModal.tsx b/src/ui/components/ProfileModal.tsx
index 7c42d18..d77a481 100644
--- a/src/ui/components/ProfileModal.tsx
+++ b/src/ui/components/ProfileModal.tsx
@@ -295,6 +295,30 @@ export const ProfileModal = ({
     };
   }, [account, api, targetAccountId]);
 
+  useEffect(() => {
+    if (!profileError) {
+      return;
+    }
+    showToast(profileError, { tone: "error" });
+    setProfileError(null);
+  }, [profileError, showToast]);
+
+  useEffect(() => {
+    if (!followError) {
+      return;
+    }
+    showToast(followError, { tone: "error" });
+    setFollowError(null);
+  }, [followError, showToast]);
+
+  useEffect(() => {
+    if (!itemsError) {
+      return;
+    }
+    showToast(itemsError, { tone: "error" });
+    setItemsError(null);
+  }, [itemsError, showToast]);
+
   const updateItem = useCallback((next: Status) => {
     setItems((current) => current.map((item) => (item.id === next.id ? next : item)));
   }, []);
@@ -605,7 +629,6 @@ export const ProfileModal = ({
         const message = error instanceof Error ? error.message : fallbackMessage;
         setRelationship(previous);
         setFollowError(message);
-        showToast(message, { tone: "error" });
       } finally {
         setFollowLoading(false);
       }
@@ -908,9 +931,7 @@ export const ProfileModal = ({
               ) : null}
             </div>
           </div>
-          {followError ? <p className="error">{followError}</p> : null}
           {profileLoading ? <p className="empty">프로필을 불러오는 중...</p> : null}
-          {profileError ? <p className="error">{profileError}</p> : null}
           {bioContent
             ? bioContent.type === "html"
               ? <div className="profile-bio" dangerouslySetInnerHTML={{ __html: bioContent.value }} />
@@ -929,7 +950,6 @@ export const ProfileModal = ({
         </section>
         <section className="profile-posts">
           <h4>작성한 글</h4>
-          {itemsError ? <p className="error">{itemsError}</p> : null}
           {itemsLoading && items.length === 0 ? <p className="empty">게시글을 불러오는 중...</p> : null}
           {!itemsLoading && items.length === 0 ? <p className="empty">표시할 글이 없습니다.</p> : null}
           {items.length > 0 ? (
diff --git a/src/ui/components/ReactionPicker.tsx b/src/ui/components/ReactionPicker.tsx
index 3b1ea6e..18f507b 100644
--- a/src/ui/components/ReactionPicker.tsx
+++ b/src/ui/components/ReactionPicker.tsx
@@ -3,6 +3,7 @@ import type { Account, ReactionInput } from "../../domain/types";
 import type { MastodonApi } from "../../services/MastodonApi";
 import { useClickOutside } from "../hooks/useClickOutside";
 import { useEmojiManager, type EmojiItem } from "../hooks/useEmojiManager";
+import { useToast } from "../state/ToastContext";
 
 export const ReactionPicker = ({
   account,
@@ -21,6 +22,8 @@ export const ReactionPicker = ({
   const [emojiSearchQuery, setEmojiSearchQuery] = useState("");
   const buttonRef = useRef<HTMLButtonElement | null>(null);
   const panelRef = useRef<HTMLDivElement | null>(null);
+  const { showToast } = useToast();
+  const lastEmojiErrorRef = useRef<string | null>(null);
 
   // useEmojiManager 훅 사용
   const {
@@ -37,6 +40,19 @@ export const ReactionPicker = ({
     searchEmojis
   } = useEmojiManager(account, api, false);
 
+  useEffect(() => {
+    if (emojiStatus !== "error") {
+      lastEmojiErrorRef.current = null;
+      return;
+    }
+    const message = emojiError ?? "이모지를 불러오지 못했습니다.";
+    if (message === lastEmojiErrorRef.current) {
+      return;
+    }
+    lastEmojiErrorRef.current = message;
+    showToast(message, { tone: "error" });
+  }, [emojiError, emojiStatus, showToast]);
+
   const emojiSearchResults = useMemo(() => {
     if (!emojiSearchQuery.trim()) {
       return [];
diff --git a/src/ui/components/StatusModal.tsx b/src/ui/components/StatusModal.tsx
index 9bc2190..d65a77f 100644
--- a/src/ui/components/StatusModal.tsx
+++ b/src/ui/components/StatusModal.tsx
@@ -3,6 +3,7 @@ import type { Account, CustomEmoji, Status, ThreadContext } from "../../domain/t
 import type { MastodonApi } from "../../services/MastodonApi";
 import { TimelineItem } from "./TimelineItem";
 import BoostIcon from "../assets/boost-icon.svg?react";
+import { useToast } from "../state/ToastContext";
 
 export const StatusModal = ({
   status,
@@ -120,6 +121,7 @@ export const StatusModal = ({
   const [threadContext, setThreadContext] = useState<ThreadContext | null>(null);
   const [isLoadingThread, setIsLoadingThread] = useState(false);
   const [threadError, setThreadError] = useState<string | null>(null);
+  const { showToast } = useToast();
 
   // 스레드 컨텍스트 가져오기
   useEffect(() => {
@@ -145,6 +147,14 @@ export const StatusModal = ({
     fetchThreadContext();
   }, [account, api, displayStatus.id]);
 
+  useEffect(() => {
+    if (!threadError) {
+      return;
+    }
+    showToast(threadError, { tone: "error" });
+    setThreadError(null);
+  }, [showToast, threadError]);
+
   return (
     <div
       className="status-modal"
@@ -268,11 +278,6 @@ export const StatusModal = ({
           
           {/* 로딩 상태는 헤더에서 처리 */}
           
-          {threadError && (
-            <div className="thread-error">
-              <span>{threadError}</span>
-            </div>
-          )}
         </div>
       </div>
     </div>
diff --git a/src/ui/styles/themes/dark.css b/src/ui/styles/themes/dark.css
index 85ec74e..7f3f287 100644
--- a/src/ui/styles/themes/dark.css
+++ b/src/ui/styles/themes/dark.css
@@ -494,6 +494,127 @@
     --color-image-modal-delete-bg: #c62828;
     --color-image-modal-delete-text: #fff5f5;
   }
+
+  :root:not([data-color-scheme="light"])[data-theme="matcha-core"] {
+    --page-background: radial-gradient(circle at top left, #0f1a13, #0a120e 55%, #060b08);
+    --color-text-primary: #c6f3d0;
+    --scrollbar-thumb: #3b6e50;
+    --notification-badge-ring: #0d120f;
+    --color-overlay-backdrop: rgba(4, 12, 8, 0.6);
+    --color-panel-bg: #0c1410cc;
+    --color-panel-border: #1f3a2b;
+    --shadow-panel: 0 18px 40px rgba(0, 0, 0, 0.55);
+    --color-timeline-column-bg: #0b130f;
+    --color-timeline-column-border: #1f3a2b;
+    --shadow-timeline-column: inset 0 1px 0 rgba(255, 255, 255, 0.04), 0 12px 24px rgba(0, 0, 0, 0.45);
+    --color-status-bg: #0b130f;
+    --color-status-border: #1f3a2b;
+    --color-status-header: #a8e4b6;
+    --color-app-header-text: #a8e4b6;
+    --color-status-header-strong: #d8fde0;
+    --color-status-meta: #7edc93;
+    --color-status-time: #7edc93;
+    --color-status-warning-bg: #132019;
+    --color-status-warning-text: #9fe8b3;
+    --color-status-link: #6ce48b;
+    --color-link-preview-bg: #0b130f;
+    --color-link-preview-border: #1f3a2b;
+    --color-link-preview-text: #a8e4b6;
+    --color-link-preview-strong: #d8fde0;
+    --color-link-preview-url: #6ce48b;
+    --color-reaction-text: #c6f3d0;
+    --color-reaction-border: #2b4a38;
+    --color-reaction-active-bg: #13271c;
+    --color-reaction-active-border: #2b4a38;
+    --color-reaction-active-text: #e6ffee;
+    --color-account-add-button-bg: #39b56b;
+    --color-account-add-button-text: #0b140f;
+    --color-account-add-panel-bg: rgba(11, 19, 15, 0.88);
+    --color-account-add-panel-text: #c6f3d0;
+    --color-account-add-panel-border: #1f3a2b;
+    --shadow-account-add-panel: 0 18px 40px rgba(0, 0, 0, 0.55);
+    --color-section-menu-bg: rgba(11, 19, 15, 0.88);
+    --color-section-menu-text: #c6f3d0;
+    --color-section-menu-border: #1f3a2b;
+    --shadow-section-menu: 0 18px 40px rgba(0, 0, 0, 0.55);
+    --color-section-menu-danger: #e07a6d;
+    --color-toast-success-bg: #133021;
+    --color-toast-success-border: #2f8a5d;
+    --color-toast-success-text: #c9f5d6;
+    --color-toast-info-bg: #0c1410;
+    --color-toast-info-border: #1f3a2b;
+    --color-toast-info-text: #c6f3d0;
+    --color-toast-error-bg: #3a1b1a;
+    --color-toast-error-border: #e07a6d;
+    --color-toast-error-text: #f6d4cf;
+    --color-account-selector-bg: #0b130f;
+    --color-account-selector-border: #1f3a2b;
+    --shadow-account-selector: 0 18px 40px rgba(0, 0, 0, 0.55);
+    --color-account-selector-placeholder: #8cd49a;
+    --color-account-handle: #a8e4b6;
+    --color-file-button-bg: #163126;
+    --color-file-button-text: #d7f6df;
+    --color-secondary-button-bg: #163126;
+    --color-secondary-button-text: #d7f6df;
+    --color-secondary-button-border: #1f3a2b;
+    --color-emoji-panel-bg: #0b130f;
+    --color-emoji-panel-border: #1f3a2b;
+    --color-emoji-toggle-bg: #13271c;
+    --color-emoji-toggle-text: #c6f3d0;
+    --color-emoji-toggle-border: #1f3a2b;
+    --color-emoji-count-bg: #1f3a2b;
+    --color-emoji-count-text: #d8fde0;
+    --color-emoji-button-bg: #13271c;
+    --color-emoji-button-border: #1f3a2b;
+    --color-emoji-empty-text: #7fb88f;
+    --color-compose-busy-backdrop: rgba(5, 12, 8, 0.65);
+    --color-compose-busy-bg: #0c1410;
+    --color-compose-busy-border: #1f3a2b;
+    --color-compose-busy-text: #a8e4b6;
+    --color-compose-busy-spinner-border: #1f3a2b;
+    --color-compose-busy-spinner-active: #6ce48b;
+    --color-input-bg: #0a120e;
+    --color-input-border: #1f3a2b;
+    --color-input-text: #c6f3d0;
+    --color-input-placeholder: #6f9f7f;
+    --color-settings-select-bg: #0a120e;
+    --color-settings-select-border: #1f3a2b;
+    --color-settings-select-text: #c6f3d0;
+    --color-compose-input-bg: #0a120e;
+    --color-attachments-bg: #101c15;
+    --color-attachments-border: #1f3a2b;
+    --color-attachment-add-border: #6ce48b;
+    --color-attachment-add-text: #8cd49a;
+    --color-action-bg: #39b56b;
+    --color-action-text: #0b140f;
+    --color-action-danger-bg: #b5463b;
+    --color-action-danger-text: #fff6f0;
+    --color-action-active-bg: #6ce48b;
+    --color-action-active-text: #0c1a12;
+    --color-action-ghost-text: #6ce48b;
+    --color-link: #6ce48b;
+    --color-sidebar-description: #a8e4b6;
+    --color-brand-text: #a8e4b6;
+    --color-oss-list: #a8e4b6;
+    --color-sidebar-description-link: #6ce48b;
+    --color-sidebar-link: #6ce48b;
+    --color-sidebar-divider: #1f3a2b;
+    --color-settings-item-border: #1f3a2b;
+    --color-settings-item-text: #a8e4b6;
+    --color-status-backdrop: rgba(5, 12, 8, 0.7);
+    --color-status-modal-bg: #0c1410;
+    --color-status-modal-border: #1f3a2b;
+    --color-status-modal-divider: #1f3a2b;
+    --color-status-modal-title: #c6f3d0;
+    --color-boosted-by: #7edc93;
+    --color-notification-actor: #7edc93;
+    --color-reply-info: #7edc93;
+    --color-character-count-normal: #a8e4b6;
+    --color-delete-button-bg: #b5463b;
+    --color-delete-button-text: #fff6f0;
+    --color-image-modal-delete-bg: #b5463b;
+    --color-image-modal-delete-text: #fff6f0;
+  }
 }
 
 :root[data-color-scheme="dark"] {
@@ -991,3 +1112,124 @@
   --color-image-modal-delete-bg: #c62828;
   --color-image-modal-delete-text: #fff5f5;
 }
+
+:root[data-color-scheme="dark"][data-theme="matcha-core"] {
+  --page-background: radial-gradient(circle at top left, #0f1a13, #0a120e 55%, #060b08);
+  --color-text-primary: #c6f3d0;
+  --scrollbar-thumb: #3b6e50;
+  --notification-badge-ring: #0d120f;
+  --color-overlay-backdrop: rgba(4, 12, 8, 0.6);
+  --color-panel-bg: #0c1410cc;
+  --color-panel-border: #1f3a2b;
+  --shadow-panel: 0 18px 40px rgba(0, 0, 0, 0.55);
+  --color-timeline-column-bg: #0b130f;
+  --color-timeline-column-border: #1f3a2b;
+  --shadow-timeline-column: inset 0 1px 0 rgba(255, 255, 255, 0.04), 0 12px 24px rgba(0, 0, 0, 0.45);
+  --color-status-bg: #0b130f;
+  --color-status-border: #1f3a2b;
+  --color-status-header: #a8e4b6;
+  --color-app-header-text: #a8e4b6;
+  --color-status-header-strong: #d8fde0;
+  --color-status-meta: #7edc93;
+  --color-status-time: #7edc93;
+  --color-status-warning-bg: #132019;
+  --color-status-warning-text: #9fe8b3;
+  --color-status-link: #6ce48b;
+  --color-link-preview-bg: #0b130f;
+  --color-link-preview-border: #1f3a2b;
+  --color-link-preview-text: #a8e4b6;
+  --color-link-preview-strong: #d8fde0;
+  --color-link-preview-url: #6ce48b;
+  --color-reaction-text: #c6f3d0;
+  --color-reaction-border: #2b4a38;
+  --color-reaction-active-bg: #13271c;
+  --color-reaction-active-border: #2b4a38;
+  --color-reaction-active-text: #e6ffee;
+  --color-account-add-button-bg: #39b56b;
+  --color-account-add-button-text: #0b140f;
+  --color-account-add-panel-bg: rgba(11, 19, 15, 0.88);
+  --color-account-add-panel-text: #c6f3d0;
+  --color-account-add-panel-border: #1f3a2b;
+  --shadow-account-add-panel: 0 18px 40px rgba(0, 0, 0, 0.55);
+  --color-section-menu-bg: rgba(11, 19, 15, 0.88);
+  --color-section-menu-text: #c6f3d0;
+  --color-section-menu-border: #1f3a2b;
+  --shadow-section-menu: 0 18px 40px rgba(0, 0, 0, 0.55);
+  --color-section-menu-danger: #e07a6d;
+  --color-toast-success-bg: #133021;
+  --color-toast-success-border: #2f8a5d;
+  --color-toast-success-text: #c9f5d6;
+  --color-toast-info-bg: #0c1410;
+  --color-toast-info-border: #1f3a2b;
+  --color-toast-info-text: #c6f3d0;
+  --color-toast-error-bg: #3a1b1a;
+  --color-toast-error-border: #e07a6d;
+  --color-toast-error-text: #f6d4cf;
+  --color-account-selector-bg: #0b130f;
+  --color-account-selector-border: #1f3a2b;
+  --shadow-account-selector: 0 18px 40px rgba(0, 0, 0, 0.55);
+  --color-account-selector-placeholder: #8cd49a;
+  --color-account-handle: #a8e4b6;
+  --color-file-button-bg: #163126;
+  --color-file-button-text: #d7f6df;
+  --color-secondary-button-bg: #163126;
+  --color-secondary-button-text: #d7f6df;
+  --color-secondary-button-border: #1f3a2b;
+  --color-emoji-panel-bg: #0b130f;
+  --color-emoji-panel-border: #1f3a2b;
+  --color-emoji-toggle-bg: #13271c;
+  --color-emoji-toggle-text: #c6f3d0;
+  --color-emoji-toggle-border: #1f3a2b;
+  --color-emoji-count-bg: #1f3a2b;
+  --color-emoji-count-text: #d8fde0;
+  --color-emoji-button-bg: #13271c;
+  --color-emoji-button-border: #1f3a2b;
+  --color-emoji-empty-text: #7fb88f;
+  --color-compose-busy-backdrop: rgba(5, 12, 8, 0.65);
+  --color-compose-busy-bg: #0c1410;
+  --color-compose-busy-border: #1f3a2b;
+  --color-compose-busy-text: #a8e4b6;
+  --color-compose-busy-spinner-border: #1f3a2b;
+  --color-compose-busy-spinner-active: #6ce48b;
+  --color-input-bg: #0a120e;
+  --color-input-border: #1f3a2b;
+  --color-input-text: #c6f3d0;
+  --color-input-placeholder: #6f9f7f;
+  --color-settings-select-bg: #0a120e;
+  --color-settings-select-border: #1f3a2b;
+  --color-settings-select-text: #c6f3d0;
+  --color-compose-input-bg: #0a120e;
+  --color-attachments-bg: #101c15;
+  --color-attachments-border: #1f3a2b;
+  --color-attachment-add-border: #6ce48b;
+  --color-attachment-add-text: #8cd49a;
+  --color-action-bg: #39b56b;
+  --color-action-text: #0b140f;
+  --color-action-danger-bg: #b5463b;
+  --color-action-danger-text: #fff6f0;
+  --color-action-active-bg: #6ce48b;
+  --color-action-active-text: #0c1a12;
+  --color-action-ghost-text: #6ce48b;
+  --color-link: #6ce48b;
+  --color-sidebar-description: #a8e4b6;
+  --color-brand-text: #a8e4b6;
+  --color-oss-list: #a8e4b6;
+  --color-sidebar-description-link: #6ce48b;
+  --color-sidebar-link: #6ce48b;
+  --color-sidebar-divider: #1f3a2b;
+  --color-settings-item-border: #1f3a2b;
+  --color-settings-item-text: #a8e4b6;
+  --color-status-backdrop: rgba(5, 12, 8, 0.7);
+  --color-status-modal-bg: #0c1410;
+  --color-status-modal-border: #1f3a2b;
+  --color-status-modal-divider: #1f3a2b;
+  --color-status-modal-title: #c6f3d0;
+  --color-boosted-by: #7edc93;
+  --color-notification-actor: #7edc93;
+  --color-reply-info: #7edc93;
+  --color-character-count-normal: #a8e4b6;
+  --color-delete-button-bg: #b5463b;
+  --color-delete-button-text: #fff6f0;
+  --color-image-modal-delete-bg: #b5463b;
+  --color-image-modal-delete-text: #fff6f0;
+}
diff --git a/src/ui/styles/themes/light.css b/src/ui/styles/themes/light.css
index 7a5a38f..411c26c 100644
--- a/src/ui/styles/themes/light.css
+++ b/src/ui/styles/themes/light.css
@@ -345,3 +345,122 @@
   --color-image-modal-delete-bg: #c62828;
   --color-image-modal-delete-text: #fff5f5;
 }
+
+:root[data-theme="matcha-core"] {
+  --page-background: radial-gradient(circle at top left, #f0faf1, #eef8ef 55%, #f7fff8);
+  --color-text-primary: #0f3b22;
+  --scrollbar-thumb: #7fbf92;
+  --color-sidebar-description: #2f6b46;
+  --color-brand-text: #2f6b46;
+  --color-sidebar-description-link: #1f8f4b;
+  --color-sidebar-link: #1b6f3f;
+  --color-sidebar-divider: #cfe6d5;
+  --color-settings-backdrop: rgba(10, 40, 20, 0.55);
+  --color-status-backdrop: rgba(10, 40, 20, 0.65);
+  --color-status-modal-bg: #f6fff6;
+  --color-status-modal-border: #cfe6d5;
+  --shadow-status-modal: 0 20px 60px rgba(24, 84, 48, 0.14);
+  --color-status-modal-divider: #cfe6d5;
+  --color-status-modal-title: #0f3b22;
+  --color-overlay-backdrop: rgba(15, 60, 32, 0.12);
+  --color-settings-item-border: #cfe6d5;
+  --color-settings-item-text: #2f6b46;
+  --color-panel-border: #cfe6d5;
+  --shadow-panel: 0 18px 40px rgba(24, 84, 48, 0.08);
+  --color-account-add-button-bg: #1b7a3d;
+  --color-account-add-button-text: #effff4;
+  --color-account-add-panel-bg: rgba(246, 255, 246, 0.92);
+  --color-account-add-panel-text: #0f3b22;
+  --color-account-add-panel-border: #cfe6d5;
+  --shadow-account-add-panel: 0 18px 40px rgba(24, 84, 48, 0.12);
+  --color-avatar-bg: #f6fff6;
+  --color-avatar-border: #cfe6d5;
+  --color-avatar-fallback: #9bc8ab;
+  --color-account-selector-bg: #f6fff6;
+  --color-account-selector-border: #cfe6d5;
+  --shadow-account-selector: 0 18px 40px rgba(24, 84, 48, 0.12);
+  --color-account-selector-placeholder: #2f6b46;
+  --color-account-handle: #2f6b46;
+  --color-action-bg: #1f9a50;
+  --color-action-text: #f2fff6;
+  --color-action-danger-bg: #b13b3b;
+  --color-action-danger-text: #fff4f4;
+  --color-action-active-bg: #0f5a32;
+  --color-action-active-text: #eafff2;
+  --color-action-ghost-text: #1b6f3f;
+  --color-section-menu-bg: rgba(246, 255, 246, 0.92);
+  --color-section-menu-text: #0f3b22;
+  --color-section-menu-border: #cfe6d5;
+  --shadow-section-menu: 0 18px 40px rgba(24, 84, 48, 0.12);
+  --color-toast-success-bg: #e5f6ea;
+  --color-toast-success-border: #1b7a3d;
+  --color-toast-success-text: #0f3b22;
+  --color-toast-info-bg: #f6fff6;
+  --color-toast-info-border: #cfe6d5;
+  --color-toast-info-text: #0f3b22;
+  --color-toast-error-bg: #fde9e6;
+  --color-toast-error-border: #b13b3b;
+  --color-toast-error-text: #5b1f1f;
+  --color-timeline-column-bg: #f6fff6;
+  --color-timeline-column-border: #cfe6d5;
+  --shadow-timeline-column: inset 0 1px 0 rgba(255, 255, 255, 0.5), 0 12px 24px rgba(24, 84, 48, 0.06);
+  --color-status-bg: #f8fff8;
+  --color-status-border: #cfe6d5;
+  --color-status-header: #2f6b46;
+  --color-status-header-strong: #0f3b22;
+  --color-status-meta: #1b6f3f;
+  --color-status-time: #1b6f3f;
+  --color-status-warning-bg: #e9f5ec;
+  --color-status-warning-text: #2f6b46;
+  --color-link-preview-bg: #f6fff6;
+  --color-link-preview-border: #cfe6d5;
+  --color-link-preview-text: #2f6b46;
+  --color-link-preview-strong: #0f3b22;
+  --color-link-preview-url: #1f8f4b;
+  --color-status-link: #1f8f4b;
+  --color-reaction-text: #0f3b22;
+  --color-reaction-border: #cfe6d5;
+  --color-reaction-active-bg: #1b6f3f;
+  --color-reaction-active-border: #0f3b22;
+  --color-reaction-active-text: #f2fff6;
+  --color-file-button-bg: #e9f5ec;
+  --color-file-button-text: #2f6b46;
+  --color-secondary-button-bg: #e9f5ec;
+  --color-secondary-button-text: #2f6b46;
+  --color-secondary-button-border: #cfe6d5;
+  --color-emoji-panel-bg: #f6fff6;
+  --color-emoji-panel-border: #cfe6d5;
+  --color-emoji-toggle-bg: #e9f5ec;
+  --color-emoji-toggle-text: #2f6b46;
+  --color-emoji-toggle-border: #cfe6d5;
+  --color-emoji-count-bg: #cfe6d5;
+  --color-emoji-count-text: #0f3b22;
+  --color-emoji-button-bg: #e9f5ec;
+  --color-emoji-button-border: #cfe6d5;
+  --color-emoji-empty-text: #7aa58a;
+  --color-compose-busy-backdrop: rgba(15, 60, 32, 0.2);
+  --color-compose-busy-bg: #f6fff6;
+  --color-compose-busy-border: #cfe6d5;
+  --color-compose-busy-text: #2f6b46;
+  --color-compose-busy-spinner-border: #cfe6d5;
+  --color-compose-busy-spinner-active: #1f9a50;
+  --color-boosted-by: #1b6f3f;
+  --color-notification-actor: #1b6f3f;
+  --color-reply-info: #1b6f3f;
+  --color-input-bg: #f6fff6;
+  --color-input-border: #cfe6d5;
+  --color-input-text: #0f3b22;
+  --color-input-placeholder: #7aa58a;
+  --color-settings-select-bg: #f6fff6;
+  --color-settings-select-border: #cfe6d5;
+  --color-settings-select-text: #0f3b22;
+  --color-compose-input-bg: #f6fff6;
+  --color-attachments-bg: #e9f5ec;
+  --color-attachments-border: #cfe6d5;
+  --color-attachment-add-border: #a8cdb4;
+  --color-attachment-add-text: #2f6b46;
+  --color-delete-button-bg: #b13b3b;
+  --color-delete-button-text: #fff4f4;
+  --color-image-modal-delete-bg: #b13b3b;
+  --color-image-modal-delete-text: #fff4f4;
+}