diff --git a/platform_web/components/OperationControls.test.tsx b/platform_web/components/OperationControls.test.tsx
index c8f71a4..0a895f4 100644
--- a/platform_web/components/OperationControls.test.tsx
+++ b/platform_web/components/OperationControls.test.tsx
@@ -22,7 +22,9 @@ describe("shared operation dialogs", () => {
     expect(html).toContain('aria-labelledby=');
     expect(html).toContain('aria-describedby=');
     expect(html).toContain('aria-busy="true"');
+    expect(html).toContain("关闭确认停用");
     expect(operationControlsSource).toContain('event.key === "Escape"');
+    expect(operationControlsSource).toContain('document.body.style.overflow = "hidden"');
     expect(operationControlsSource).toContain("previousFocus?.focus()");
   });
 
diff --git a/platform_web/components/OperationControls.tsx b/platform_web/components/OperationControls.tsx
index e457a63..0f6d37d 100644
--- a/platform_web/components/OperationControls.tsx
+++ b/platform_web/components/OperationControls.tsx
@@ -32,7 +32,13 @@ export function ConfirmDialog({ open, title, description, confirmLabel, danger,
         aria-busy={busy}
         onClick={(event) => event.stopPropagation()}
       >
-        <h2 id={titleId}>{title}</h2>
+        <div className="panel-header dialog-panel-header">
+          <h2 id={titleId}>{title}</h2>
+          <button type="button" className="theme-upload drawer-close" aria-label={`关闭${title}`} onClick={onCancel} disabled={busy}>
+            <X size={14} />
+            <span>关闭</span>
+          </button>
+        </div>
         <p id={descriptionId}>{description}</p>
         {children}
         <div className="confirm-actions">
@@ -75,7 +81,7 @@ export function ManagementDialog({ open, title, description, wide, onClose, chil
         aria-describedby={description ? descriptionId : undefined}
         onClick={(event) => event.stopPropagation()}
       >
-        <div className="panel-header">
+        <div className="panel-header dialog-panel-header">
           <h2 id={titleId}>{title}</h2>
           <button type="button" className="theme-upload drawer-close" aria-label={`关闭${title}`} onClick={onClose}>
             <X size={14} />
@@ -109,8 +115,11 @@ function useDialogLifecycle(open: boolean, onClose: () => void, canClose: boolea
     }
 
     document.addEventListener("keydown", handleKeyDown);
+    const previousBodyOverflow = document.body.style.overflow;
+    document.body.style.overflow = "hidden";
     return () => {
       document.removeEventListener("keydown", handleKeyDown);
+      document.body.style.overflow = previousBodyOverflow;
       previousFocus?.focus();
     };
   }, [canClose, onClose, open]);
diff --git a/platform_web/pages/ConsolePages.test.tsx b/platform_web/pages/ConsolePages.test.tsx
index 0f65816..ccfc652 100644
--- a/platform_web/pages/ConsolePages.test.tsx
+++ b/platform_web/pages/ConsolePages.test.tsx
@@ -239,7 +239,7 @@ describe("first-party console pages", () => {
     expect(html).not.toContain("role=\"dialog\"");
   });
 
-  it("labels uploaded profile backgrounds as active and built-in presets as fallback", () => {
+  it("keeps profile background controls focused on custom uploads", () => {
     const originalWindow = globalThis.window;
     Object.defineProperty(globalThis, "window", {
       configurable: true,
@@ -265,10 +265,12 @@ describe("first-party console pages", () => {
       const html = renderToStaticMarkup(<ProfileSettingsPage {...pageProps()} />);
 
       expect(html).toContain("自定义背景");
-      expect(html).toContain("机甲格纳库");
-      expect(html).toContain("备用");
-      expect(html).toContain("当前显示自定义上传背景；机甲格纳库 仅作为移除上传后的备用桌面。");
-      expect(html).toContain('aria-pressed="false"');
+      expect(html).toContain("上传背景");
+      expect(html).toContain("移除背景");
+      expect(html).toContain("当前显示自定义上传背景；移除后回到主题配色背景。");
+      expect(html).not.toContain("机甲格纳库");
+      expect(html).not.toContain("粉月魔法阵");
+      expect(html).not.toContain("备用");
     } finally {
       Object.defineProperty(globalThis, "window", {
         configurable: true,
diff --git a/platform_web/pages/ProfileSettingsPage.tsx b/platform_web/pages/ProfileSettingsPage.tsx
index a5951c7..ac4e4de 100644
--- a/platform_web/pages/ProfileSettingsPage.tsx
+++ b/platform_web/pages/ProfileSettingsPage.tsx
@@ -5,15 +5,11 @@ import type { PageComponentProps } from "../contracts/page";
 import { defaultPageForUser } from "../routes/routes";
 import {
   applyBackgroundImage,
-  applyThemeBackgroundPreset,
   applyThemePalette,
   loadThemeState,
   persistBackgroundImage,
-  persistThemeBackgroundPreset,
   persistThemePalette,
-  themeBackgroundPresets,
   themePalettes,
-  type ThemeBackgroundId,
   type ThemePaletteId,
   type WorkspaceThemeState
 } from "../theme/tokens";
@@ -46,9 +42,8 @@ export function ProfileSettingsPage({ session, onNavigate, onLogout, onProfileSa
   }, [session]);
 
   const activePalette = useMemo(() => themePalettes.find((palette) => palette.id === themeState.paletteId) ?? themePalettes[0], [themeState.paletteId]);
-  const activeBackground = useMemo(() => themeBackgroundPresets.find((preset) => preset.id === themeState.backgroundPresetId) ?? themeBackgroundPresets[0], [themeState.backgroundPresetId]);
   const hasCustomBackground = Boolean(themeState.backgroundImage);
-  const backgroundMetricValue = hasCustomBackground ? "自定义背景" : activeBackground.label;
+  const backgroundMetricValue = hasCustomBackground ? "已上传" : "主题配色";
 
   async function saveProfile(event: FormEvent<HTMLFormElement>) {
     event.preventDefault();
@@ -91,16 +86,6 @@ export function ProfileSettingsPage({ session, onNavigate, onLogout, onProfileSa
     });
   }
 
-  function selectBackgroundPreset(backgroundPresetId: ThemeBackgroundId) {
-    applyThemeBackgroundPreset(backgroundPresetId);
-    persistThemeBackgroundPreset(backgroundPresetId);
-    setThemeState((current) => {
-      const nextState = { ...current, backgroundPresetId };
-      void persistThemePreference(nextState);
-      return nextState;
-    });
-  }
-
   function handleBackgroundUpload(event: ChangeEvent<HTMLInputElement>) {
     const file = event.target.files?.[0];
     event.target.value = "";
@@ -219,31 +204,8 @@ export function ProfileSettingsPage({ session, onNavigate, onLogout, onProfileSa
             ))}
           </div>
           <div className="profile-panel-title">
-            <MoonStar size={15} />
-            <strong>背景桌面</strong>
-          </div>
-          <div className="background-preset-grid profile-background-grid">
-            {themeBackgroundPresets.map((preset) => {
-              const isFallbackPreset = preset.id === themeState.backgroundPresetId;
-              const isVisiblePreset = isFallbackPreset && !hasCustomBackground;
-              return (
-                <button
-                  key={preset.id}
-                  type="button"
-                  className={cx("background-preset-option", isVisiblePreset && "background-preset-option-active", hasCustomBackground && isFallbackPreset && "background-preset-option-fallback")}
-                  aria-pressed={isVisiblePreset}
-                  title={hasCustomBackground ? `${preset.summary}，当前自定义背景正在显示；此预设会在移除上传背景后显示` : preset.summary}
-                  onClick={() => selectBackgroundPreset(preset.id)}
-                >
-                  <span className="background-preset-preview" style={{ background: preset.preview }} aria-hidden="true" />
-                  <span className="background-preset-label">
-                    {isVisiblePreset ? <Sparkles size={13} /> : <MoonStar size={13} />}
-                    {preset.label}
-                    {hasCustomBackground && isFallbackPreset && <span className="background-preset-fallback-badge">备用</span>}
-                  </span>
-                </button>
-              );
-            })}
+            <Upload size={15} />
+            <strong>自定义背景</strong>
           </div>
           <div className="theme-background-actions">
             <label className="theme-upload" title="上传自定义背景桌面">
@@ -258,7 +220,7 @@ export function ProfileSettingsPage({ session, onNavigate, onLogout, onProfileSa
               </button>
             )}
           </div>
-          <span className="theme-background-note">{themeState.backgroundImage ? `当前显示自定义上传背景；${activeBackground.label} 仅作为移除上传后的备用桌面。` : "当前使用内置背景桌面。"}</span>
+          <span className="theme-background-note">{themeState.backgroundImage ? "当前显示自定义上传背景；移除后回到主题配色背景。" : "当前仅使用主题配色背景。"}</span>
         </section>
       </section>
     </div>
diff --git a/platform_web/theme/base-css.test.js b/platform_web/theme/base-css.test.js
index ed21682..f7148fd 100644
--- a/platform_web/theme/base-css.test.js
+++ b/platform_web/theme/base-css.test.js
@@ -112,4 +112,45 @@ describe("platform web shared theme CSS", () => {
     expect(mobileRule).toContain(".app-nav-copy strong");
     expect(mobileRule).toContain("display: block");
   });
+
+  it("keeps desktop sidebar controls pinned inside the viewport", () => {
+    const themeCss = readFileSync(new URL("./base.css", import.meta.url), "utf8");
+    const shellRule = themeCss.slice(themeCss.indexOf(".app-shell {"), themeCss.indexOf(".workspace-background-layer"));
+    const sidebarRule = themeCss.slice(themeCss.indexOf(".app-sidebar {"), themeCss.indexOf(".app-brand {"));
+
+    expect(shellRule).toContain("min-height: 100dvh");
+    expect(sidebarRule).toContain("position: sticky");
+    expect(sidebarRule).toContain("height: 100dvh");
+    expect(sidebarRule).toContain("overflow-y: auto");
+    expect(sidebarRule).toContain("overscroll-behavior: contain");
+  });
+
+  it("keeps dialogs and drawers internally scrollable on short viewports", () => {
+    const themeCss = readFileSync(new URL("./base.css", import.meta.url), "utf8");
+    const dialogRule = themeCss.slice(themeCss.indexOf("/* ---- drawer ---- */"), themeCss.indexOf(".plugin-detail-actions"));
+    const confirmStart = themeCss.indexOf("/* ---- confirm dialog ---- */");
+    const confirmRule = themeCss.slice(confirmStart, themeCss.indexOf(".confirm-actions {", confirmStart));
+    const mobileRule = themeCss.slice(themeCss.indexOf("/* ---- narrow screens ---- */"), themeCss.indexOf("/* A state view inside an already framed surface"));
+
+    expect(dialogRule).toContain(".dialog-panel-header");
+    expect(dialogRule).toContain(".drawer-panel > .panel-header");
+    expect(dialogRule).toContain("position: sticky");
+    expect(dialogRule).toContain("overflow-y: auto");
+    expect(dialogRule).toContain("overscroll-behavior: contain");
+    expect(confirmRule).toContain("max-height: calc(100dvh - 32px)");
+    expect(confirmRule).toContain("overflow-y: auto");
+    expect(mobileRule).toContain("max-height: calc(100dvh - 20px)");
+  });
+
+  it("keeps magical card decoration from becoming square background patches", () => {
+    const themeCss = readFileSync(new URL("./base.css", import.meta.url), "utf8");
+    const magicalSurfaceRule = themeCss.slice(
+      themeCss.indexOf(':root[data-theme-palette="magical-girl"] .metric-card'),
+      themeCss.indexOf(':root[data-theme-palette="magical-girl"] :where(')
+    );
+
+    expect(magicalSurfaceRule).toContain("background: var(--panel-material)");
+    expect(magicalSurfaceRule).not.toContain("background-size: 56px 56px");
+    expect(magicalSurfaceRule).not.toContain("background-image: var(--corner-sparkle), var(--panel-material)");
+  });
 });
diff --git a/platform_web/theme/base.css b/platform_web/theme/base.css
index 0e349f7..ae601db 100644
--- a/platform_web/theme/base.css
+++ b/platform_web/theme/base.css
@@ -102,7 +102,7 @@ button {
 /* ---- app shell with themed background ---- */
 
 .app-shell {
-  min-height: 100vh;
+  min-height: 100dvh;
   display: grid;
   grid-template-columns: var(--sidebar-width, 216px) minmax(0, 1fr);
   position: relative;
@@ -125,12 +125,12 @@ button {
   position: fixed;
   inset: 0;
   z-index: 0;
-  background-image: var(--workspace-background-image), var(--workspace-background-pattern-image);
-  background-size: cover, var(--workspace-background-pattern-size);
-  background-position: center, var(--workspace-background-pattern-position);
-  background-repeat: no-repeat, var(--workspace-background-pattern-repeat);
-  filter: var(--workspace-background-pattern-filter);
-  opacity: var(--workspace-background-pattern-opacity);
+  background-image: var(--workspace-background-image);
+  background-size: cover;
+  background-position: center;
+  background-repeat: no-repeat;
+  filter: none;
+  opacity: 0;
   pointer-events: none;
 }
 
@@ -389,13 +389,16 @@ button {
 }
 
 .app-sidebar {
-  position: relative;
+  position: sticky;
+  top: 0;
   z-index: 1;
   display: flex;
   flex-direction: column;
   gap: 14px;
   width: var(--sidebar-width, 216px);
   min-width: 0;
+  height: 100dvh;
+  max-height: 100dvh;
   padding: 16px 10px;
   border-right: 1px solid color-mix(in srgb, var(--line) 72%, transparent);
   background:
@@ -404,6 +407,10 @@ button {
   backdrop-filter: blur(26px) saturate(1.2);
   box-shadow: inset -1px 0 0 color-mix(in srgb, var(--rim-light) 24%, transparent), 12px 0 34px rgba(0, 0, 0, 0.34);
   transition: width 180ms ease, padding 180ms ease;
+  overflow-x: hidden;
+  overflow-y: auto;
+  overscroll-behavior: contain;
+  scrollbar-gutter: stable;
 }
 
 .app-brand {
@@ -1028,6 +1035,7 @@ button {
 .theme-upload {
   display: inline-flex;
   align-items: center;
+  justify-content: center;
   gap: 6px;
   min-height: 32px;
   padding: 0 10px;
@@ -1038,9 +1046,16 @@ button {
   cursor: pointer;
   font-size: 12px;
   font-weight: 700;
+  line-height: 1;
+  white-space: nowrap;
   box-shadow: inset 0 1px 0 var(--crystal-rim);
 }
 
+.theme-upload svg,
+.theme-upload span {
+  flex: 0 0 auto;
+}
+
 .theme-upload:hover,
 .theme-upload:focus-visible {
   border-color: var(--accent);
@@ -1064,9 +1079,7 @@ button {
   background:
     radial-gradient(900px 430px at 82% 10%, var(--background-glow-1), transparent 64%),
     radial-gradient(740px 420px at 14% 82%, var(--background-glow-3), transparent 62%),
-    var(--workspace-background-pattern-image),
     var(--background-base);
-  background-size: auto, auto, var(--workspace-background-pattern-size), auto;
 }
 
 .auth-card {
@@ -1329,15 +1342,9 @@ button {
   justify-content: center;
   border: 1px solid var(--crystal-rim);
   border-radius: 50%;
-  background:
-    var(--corner-sparkle),
-    radial-gradient(circle at 30% 20%, rgba(255, 255, 255, 0.86), transparent 34%),
-    linear-gradient(135deg, var(--pink), var(--accent));
-  background-size: 54px 54px, auto, auto;
-  background-position: right -5px top -4px, center, center;
-  background-repeat: no-repeat;
-  color: #ffffff;
-  box-shadow: var(--jelly-inset), 0 10px 26px var(--candy-glow), 0 0 18px var(--moonbeam);
+  background: color-mix(in srgb, var(--surface-solid) 36%, transparent);
+  color: var(--ink);
+  box-shadow: inset 0 1px 0 color-mix(in srgb, var(--rim-light) 28%, transparent);
   overflow: hidden;
 }
 
@@ -1481,17 +1488,18 @@ button {
   min-height: 30px;
   padding: 0 10px;
   border-radius: 999px;
-  border: 1px solid rgba(255, 255, 255, 0.58);
-  background: var(--glass-wash), var(--gold-soft);
-  color: #6f4d00;
+  border: 1px solid color-mix(in srgb, var(--line-strong) 54%, rgba(255, 255, 255, 0.16));
+  background: color-mix(in srgb, var(--surface-solid) 78%, rgba(255, 255, 255, 0.08));
+  color: var(--ink);
   font-size: 13px;
   white-space: nowrap;
-  box-shadow: inset 0 1px 0 var(--crystal-rim), 0 8px 20px var(--glass-shadow);
+  box-shadow: inset 0 1px 0 color-mix(in srgb, var(--rim-light) 26%, transparent);
 }
 
 .page-status-ready {
-  background: var(--success-soft);
-  color: var(--success);
+  background: color-mix(in srgb, var(--success-soft) 72%, var(--surface-solid));
+  border-color: color-mix(in srgb, var(--success) 42%, var(--line));
+  color: color-mix(in srgb, var(--success) 82%, var(--ink));
 }
 
 .page-summary-strip {
@@ -1725,10 +1733,7 @@ button {
 :root[data-theme-palette="magical-girl"] .confirm-panel,
 :root[data-theme-palette="magical-girl"] .plugin-group,
 :root[data-theme-palette="magical-girl"] .operation-item {
-  background-image: var(--corner-sparkle), var(--panel-material);
-  background-size: 56px 56px, auto;
-  background-position: right 6px top 4px, center;
-  background-repeat: no-repeat, no-repeat;
+  background: var(--panel-material);
   overflow: visible;
 }
 
@@ -2521,6 +2526,29 @@ button {
   opacity: var(--frame-accessory-opacity);
 }
 
+:where(
+  .metric-card,
+  .overview-card,
+  .console-panel,
+  .catalog-card,
+  .server-card,
+  .server-detail-header,
+  .resource-table-wrap,
+  .provider-table-wrap,
+  .server-table-wrap,
+  .plugin-group,
+  .operation-item,
+  .confirm-panel,
+  .drawer-panel,
+  .server-toolbar,
+  .state-view
+)::after {
+  content: none;
+  background: none;
+  box-shadow: none;
+  filter: none;
+}
+
 .resource-table,
 .provider-table {
   width: 100%;
@@ -3567,12 +3595,14 @@ button {
   backdrop-filter: blur(6px);
   display: flex;
   justify-content: flex-end;
+  overflow-y: auto;
+  overscroll-behavior: contain;
 }
 
 .drawer-panel {
   width: min(440px, 100%);
   height: 100%;
-  overflow: auto;
+  max-height: 100dvh;
   display: grid;
   align-content: start;
   gap: 14px;
@@ -3582,7 +3612,9 @@ button {
   border-left: 1px solid var(--line);
   box-shadow: inset 1px 0 0 var(--crystal-rim), -18px 0 42px var(--glass-shadow);
   position: relative;
-  overflow: hidden;
+  overflow-x: hidden;
+  overflow-y: auto;
+  overscroll-behavior: contain;
 }
 
 .plugin-detail-panel {
@@ -3596,10 +3628,11 @@ button {
 }
 
 .management-dialog-panel {
-  width: min(720px, 100%);
+  width: min(720px, calc(100vw - 32px));
   height: auto;
   max-height: min(760px, calc(100dvh - 32px));
-  overflow: auto;
+  overflow-x: hidden;
+  overflow-y: auto;
   border: 1px solid var(--line);
   border-left: 1px solid var(--line);
   border-radius: 8px;
@@ -3607,7 +3640,49 @@ button {
 }
 
 .management-dialog-wide {
-  width: min(920px, 100%);
+  width: min(920px, calc(100vw - 32px));
+}
+
+.management-dialog-backdrop {
+  place-items: center;
+  overflow-y: auto;
+  overscroll-behavior: contain;
+}
+
+:root[data-theme-palette] .drawer-panel,
+:root[data-theme-palette] .management-dialog-panel,
+:root[data-theme-palette] .confirm-panel {
+  overflow-x: hidden;
+  overflow-y: auto;
+}
+
+.dialog-panel-header,
+.drawer-panel > .panel-header,
+.confirm-panel > .panel-header {
+  position: sticky;
+  top: -20px;
+  z-index: 4;
+  margin: -20px -20px 12px;
+  padding: 16px 20px 12px;
+  border-bottom: 1px solid color-mix(in srgb, var(--line) 72%, transparent);
+  background: var(--glass-wash), var(--surface-raised);
+  -webkit-backdrop-filter: blur(20px) saturate(1.12);
+  backdrop-filter: blur(20px) saturate(1.12);
+}
+
+.management-dialog-panel .dialog-form > .confirm-actions,
+.drawer-panel > .confirm-actions,
+.confirm-panel > .confirm-actions,
+.runtime-task-actions {
+  position: sticky;
+  bottom: -20px;
+  z-index: 4;
+  margin: 4px -20px -20px;
+  padding: 12px 20px 16px;
+  border-top: 1px solid color-mix(in srgb, var(--line) 72%, transparent);
+  background: var(--glass-wash), var(--surface-raised);
+  -webkit-backdrop-filter: blur(20px) saturate(1.12);
+  backdrop-filter: blur(20px) saturate(1.12);
 }
 
 .dialog-description {
@@ -3931,7 +4006,7 @@ button {
   padding: 13px;
   border: 1px solid var(--line);
   border-radius: 8px;
-  background: var(--corner-sparkle), var(--jelly-highlight), var(--glass-wash), var(--surface);
+  background: var(--corner-sparkle), var(--surface);
   background-size: 52px 52px, auto, auto, auto;
   background-position: right 8px top 6px, center, center, center;
   background-repeat: no-repeat;
@@ -4225,10 +4300,13 @@ button {
   padding: 16px;
   background: rgba(61, 36, 65, 0.38);
   backdrop-filter: blur(6px);
+  overflow-y: auto;
+  overscroll-behavior: contain;
 }
 
 .confirm-panel {
   width: min(460px, 100%);
+  max-height: calc(100dvh - 32px);
   display: grid;
   gap: 14px;
   padding: 20px;
@@ -4238,7 +4316,9 @@ button {
   backdrop-filter: blur(24px) saturate(1.28);
   box-shadow: var(--jelly-inset), inset 0 0 0 1px var(--diamond-line), 0 18px 48px var(--glass-shadow), 0 0 34px var(--moonbeam);
   position: relative;
-  overflow: hidden;
+  overflow-x: hidden;
+  overflow-y: auto;
+  overscroll-behavior: contain;
 }
 
 .confirm-panel h2 {
@@ -4916,6 +4996,38 @@ button {
 
   .drawer-panel {
     width: 100%;
+    max-height: 100dvh;
+  }
+
+  .confirm-backdrop {
+    padding: max(10px, env(safe-area-inset-top)) 10px max(10px, env(safe-area-inset-bottom));
+    place-items: stretch center;
+  }
+
+  .confirm-panel,
+  .management-dialog-panel,
+  .management-dialog-wide {
+    width: min(100%, calc(100vw - 20px));
+    max-height: calc(100dvh - 20px);
+  }
+
+  .management-dialog-panel .management-form,
+  .management-dialog-panel .provider-form .form-grid {
+    grid-template-columns: 1fr;
+  }
+
+  .management-dialog-panel .dialog-form > .confirm-actions,
+  .drawer-panel > .confirm-actions,
+  .confirm-panel > .confirm-actions,
+  .runtime-task-actions {
+    justify-content: stretch;
+  }
+
+  .management-dialog-panel .dialog-form > .confirm-actions > *,
+  .drawer-panel > .confirm-actions > *,
+  .confirm-panel > .confirm-actions > *,
+  .runtime-task-actions > * {
+    flex: 1 1 140px;
   }
 }