diff --git a/app/game-frontend/e2e/commandArguments.spec.ts b/app/game-frontend/e2e/commandArguments.spec.ts
index 406a7ced..18e39165 100644
--- a/app/game-frontend/e2e/commandArguments.spec.ts
+++ b/app/game-frontend/e2e/commandArguments.spec.ts
@@ -1003,7 +1003,9 @@ test('shows and reserves the Ref spy command for a user on desktop and mobile',
     await picker.screenshot({ path: test.info().outputPath('spy-command-mobile-500.png') });
 });
 
-test('defaults founding to a Ref-selectable nation trait and paints color option labels', async ({ page }) => {
+test('defaults founding to a Ref-selectable nation trait and opens colored options inside the app', async ({
+    page,
+}) => {
     const foundingColors = [
         { value: 0, label: '색상 1', color: '#FF0000' },
         { value: 15, label: '색상 16', color: '#6495ED' },
@@ -1044,7 +1046,7 @@ test('defaults founding to a Ref-selectable nation trait and paints color option
         nation: [],
         inputOptions: { ...inputOptions, colors: foundingColors },
     };
-    await install(page, false, foundingCommandTable);
+    const requests = await install(page, false, foundingCommandTable);
     await page.setViewportSize({ width: 1200, height: 900 });
     await page.goto('/');
     await page.getByRole('button', { name: '1턴 명령 입력', exact: true }).click();
@@ -1060,18 +1062,30 @@ test('defaults founding to a Ref-selectable nation trait and paints color option
     await expect(nationType).toBeFocused();
 
     const colorType = picker.getByLabel('국기 색상');
-    const color16 = colorType.locator('option[value="15"]');
+    await expect(colorType).toHaveRole('button');
+    await colorType.click();
+    const colorList = picker.getByRole('listbox');
+    const color16 = colorList.getByRole('option', { name: '색상 16' });
     await expect(color16).toHaveText('색상 16');
     await expect(color16).toHaveCSS('background-color', 'rgb(100, 149, 237)');
     await expect(color16).toHaveCSS('color', 'rgb(255, 255, 255)');
-    await colorType.selectOption('15');
-    await expect(colorType).toHaveValue('15');
+    await color16.hover();
+    await color16.focus();
+    await expect(color16).toBeFocused();
+    await color16.press('Escape');
+    await expect(colorList).toBeHidden();
+    await expect(colorType).toBeFocused();
+    await colorType.click();
+    await color16.click();
+    await expect(colorType).toContainText('색상 16');
     await expect(colorType).toHaveCSS('background-color', 'rgb(100, 149, 237)');
     await expect(colorType).toHaveCSS('color', 'rgb(255, 255, 255)');
-    await colorType.selectOption('16');
+    await colorType.press('ArrowDown');
+    await page.getByRole('option', { name: '색상 17' }).press('Enter');
     await expect(colorType).toHaveCSS('background-color', 'rgb(127, 255, 212)');
     await expect(colorType).toHaveCSS('color', 'rgb(0, 0, 0)');
-    await colorType.selectOption('15');
+    await colorType.press('ArrowUp');
+    await page.getByRole('option', { name: '색상 16' }).press('Enter');
     await picker.screenshot({ path: test.info().outputPath('founding-colored-option-desktop-1200.png') });
 
     await page.setViewportSize({ width: 500, height: 900 });
@@ -1079,8 +1093,27 @@ test('defaults founding to a Ref-selectable nation trait and paints color option
     const mobilePicker = page.getByTestId('command-picker');
     await mobilePicker.getByRole('button', { name: '국가', exact: true }).click();
     await mobilePicker.getByRole('button', { name: '건국', exact: true }).click();
+    await mobilePicker.getByLabel('국가명').fill('신국');
     const mobileColorType = mobilePicker.getByLabel('국기 색상');
-    await mobileColorType.selectOption('15');
+    await mobileColorType.click();
+    const mobileColorList = mobilePicker.getByRole('listbox');
+    const mobileColor16 = mobileColorList.getByRole('option', { name: '색상 16' });
+    await expect(mobileColor16).toBeVisible();
+    await expect(mobileColor16).toHaveCSS('background-color', 'rgb(100, 149, 237)');
+    await expect(mobileColor16).toHaveCSS('color', 'rgb(255, 255, 255)');
+    const mobileOptionRect = await mobileColor16.evaluate((element) => element.getBoundingClientRect().toJSON());
+    expect(mobileOptionRect.height).toBeGreaterThanOrEqual(44);
+    const mobileListGeometry = await mobileColorList.evaluate((element) => ({
+        bottom: element.getBoundingClientRect().bottom,
+        scrollHeight: element.scrollHeight,
+        clientHeight: element.clientHeight,
+    }));
+    const mobilePickerBottom = await mobilePicker.evaluate((element) => element.getBoundingClientRect().bottom);
+    expect(mobileListGeometry.bottom).toBeLessThanOrEqual(mobilePickerBottom);
+    expect(mobileListGeometry.scrollHeight).toBeGreaterThanOrEqual(mobileListGeometry.clientHeight);
+    await mobilePicker.screenshot({ path: test.info().outputPath('founding-color-options-open-mobile-500.png') });
+    await mobileColor16.click();
+    await expect(mobileColorType).toContainText('색상 16');
     await expect(mobileColorType).toHaveCSS('background-color', 'rgb(100, 149, 237)');
     await expect(mobileColorType).toHaveCSS('color', 'rgb(255, 255, 255)');
     const colorSelectRect = await mobileColorType.evaluate((element) => element.getBoundingClientRect().toJSON());
@@ -1088,6 +1121,9 @@ test('defaults founding to a Ref-selectable nation trait and paints color option
     expect(colorSelectRect.right).toBeLessThanOrEqual(500);
     await expect.poll(() => page.evaluate(() => document.documentElement.scrollWidth)).toBeLessThanOrEqual(500);
     await mobilePicker.screenshot({ path: test.info().outputPath('founding-colored-option-mobile-500.png') });
+    await mobilePicker.getByRole('button', { name: '입력', exact: true }).click();
+    await expect(page.locator('[data-command-scope="general"] .action-column > div').first()).toContainText('신국');
+    await expect.poll(() => JSON.stringify(requests)).toContain('"colorType":15');
 });
 
 test('reserves force move, retirement, and resignation from the user command picker', async ({ page }) => {
diff --git a/app/game-frontend/src/components/main/CommandArgumentForm.vue b/app/game-frontend/src/components/main/CommandArgumentForm.vue
index 3465dc3a..b1a3e97b 100644
--- a/app/game-frontend/src/components/main/CommandArgumentForm.vue
+++ b/app/game-frontend/src/components/main/CommandArgumentForm.vue
@@ -1,6 +1,7 @@
 <script setup lang="ts">
 import { computed, reactive, watch, type CSSProperties } from 'vue';
 import MapViewer from './MapViewer.vue';
+import NationColorSelect from './NationColorSelect.vue';
 import { commandArgumentPresentation, resolveCommandArgumentMapTarget } from '../command/commandArgumentPresentation';
 import { commandCityOptions } from '../command/commandArgumentOptions';
 import {
@@ -141,6 +142,11 @@ const setSelectValue = (field: CommandInputField, rawValue: string) => {
 const selectedOptionFor = (field: CommandInputField): CommandOption | undefined =>
     optionsFor(field).find((entry) => entry.value === values[field.key]);
 
+const selectedValueFor = (field: CommandInputField): string | number => {
+    const value = values[field.key];
+    return typeof value === 'string' || typeof value === 'number' ? value : '';
+};
+
 const colorOptionStyle = (field: CommandInputField, option?: CommandOption): CSSProperties | undefined => {
     if (field.optionSource === 'colors' && option?.color) {
         return {
@@ -478,6 +484,13 @@ watch(
                     </option>
                 </select>
             </div>
+            <NationColorSelect
+                v-else-if="field.kind === 'select' && field.optionSource === 'colors'"
+                :id="`command-arg-${field.key}`"
+                :model-value="selectedValueFor(field)"
+                :options="optionsFor(field)"
+                @update:model-value="setSelectValue(field, String($event))"
+            />
             <select
                 v-else-if="field.kind === 'select'"
                 :id="`command-arg-${field.key}`"
diff --git a/app/game-frontend/src/components/main/NationColorSelect.vue b/app/game-frontend/src/components/main/NationColorSelect.vue
new file mode 100644
index 00000000..e52eb45e
--- /dev/null
+++ b/app/game-frontend/src/components/main/NationColorSelect.vue
@@ -0,0 +1,213 @@
+<script setup lang="ts">
+import { computed, nextTick, onBeforeUnmount, onMounted, ref } from 'vue';
+import { legacyNationTextColor } from '../../utils/legacyNationColor';
+import type { CommandOption } from '../command/types';
+
+const props = defineProps<{
+    id: string;
+    modelValue: string | number;
+    options: CommandOption[];
+}>();
+
+const emit = defineEmits<{
+    'update:modelValue': [value: string | number];
+}>();
+
+const root = ref<HTMLElement | null>(null);
+const trigger = ref<HTMLButtonElement | null>(null);
+const open = ref(false);
+const selectedOption = computed(() => props.options.find((option) => option.value === props.modelValue));
+const selectedIndex = computed(() =>
+    Math.max(
+        props.options.findIndex((option) => option.value === props.modelValue),
+        0
+    )
+);
+
+const optionStyle = (option?: CommandOption) => {
+    if (!option?.color) return undefined;
+    return {
+        backgroundColor: option.color,
+        color: legacyNationTextColor(option.color),
+    };
+};
+
+const focusOption = async (index: number): Promise<void> => {
+    await nextTick();
+    root.value?.querySelector<HTMLButtonElement>(`[data-color-option-index="${index}"]`)?.focus();
+};
+
+const openAndFocus = (index: number): void => {
+    open.value = true;
+    void focusOption(index);
+};
+
+const toggleOpen = (): void => {
+    open.value = !open.value;
+};
+
+const selectOption = (option: CommandOption): void => {
+    emit('update:modelValue', option.value);
+    open.value = false;
+    void nextTick(() => trigger.value?.focus());
+};
+
+const handleTriggerKeydown = (event: KeyboardEvent): void => {
+    if (event.key === 'ArrowDown') {
+        event.preventDefault();
+        openAndFocus(selectedIndex.value);
+    } else if (event.key === 'ArrowUp') {
+        event.preventDefault();
+        openAndFocus(open.value ? selectedIndex.value : props.options.length - 1);
+    } else if (event.key === 'Home') {
+        event.preventDefault();
+        openAndFocus(0);
+    } else if (event.key === 'End') {
+        event.preventDefault();
+        openAndFocus(props.options.length - 1);
+    } else if (event.key === 'Escape' && open.value) {
+        event.preventDefault();
+        event.stopPropagation();
+        open.value = false;
+    }
+};
+
+const handleOptionKeydown = (event: KeyboardEvent, index: number): void => {
+    let nextIndex: number | null = null;
+    if (event.key === 'ArrowDown') nextIndex = Math.min(index + 1, props.options.length - 1);
+    else if (event.key === 'ArrowUp') nextIndex = Math.max(index - 1, 0);
+    else if (event.key === 'Home') nextIndex = 0;
+    else if (event.key === 'End') nextIndex = props.options.length - 1;
+    else if (event.key === 'Escape') {
+        event.preventDefault();
+        event.stopPropagation();
+        open.value = false;
+        void nextTick(() => trigger.value?.focus());
+        return;
+    }
+    if (nextIndex === null) return;
+    event.preventDefault();
+    void focusOption(nextIndex);
+};
+
+const handleDocumentPointerDown = (event: PointerEvent): void => {
+    if (!root.value?.contains(event.target as Node)) open.value = false;
+};
+
+onMounted(() => document.addEventListener('pointerdown', handleDocumentPointerDown));
+onBeforeUnmount(() => document.removeEventListener('pointerdown', handleDocumentPointerDown));
+</script>
+
+<template>
+    <div ref="root" class="nation-color-select">
+        <button
+            :id="id"
+            ref="trigger"
+            type="button"
+            class="nation-color-select-trigger"
+            :style="optionStyle(selectedOption)"
+            aria-haspopup="listbox"
+            :aria-expanded="open"
+            :aria-controls="`${id}-options`"
+            @click="toggleOpen"
+            @keydown="handleTriggerKeydown"
+        >
+            <span>{{ selectedOption?.label ?? '색상 선택' }}</span>
+            <span class="nation-color-select-arrow" aria-hidden="true">▾</span>
+        </button>
+        <div v-if="open" :id="`${id}-options`" class="nation-color-select-options" role="listbox">
+            <button
+                v-for="(option, index) in options"
+                :key="String(option.value)"
+                type="button"
+                class="nation-color-select-option"
+                role="option"
+                :aria-selected="option.value === modelValue"
+                :data-color-option-index="index"
+                :style="optionStyle(option)"
+                @click="selectOption(option)"
+                @keydown="handleOptionKeydown($event, index)"
+            >
+                <span>{{ option.label }}</span>
+                <span v-if="option.value === modelValue" aria-hidden="true">✓</span>
+            </button>
+        </div>
+    </div>
+</template>
+
+<style scoped>
+.nation-color-select {
+    position: relative;
+    min-width: 0;
+    margin: 4px 6px 4px 0;
+}
+
+.nation-color-select-trigger,
+.nation-color-select-option {
+    display: grid;
+    grid-template-columns: minmax(0, 1fr) auto;
+    align-items: center;
+    width: 100%;
+    border: 1px solid rgba(201, 164, 90, 0.45);
+    padding: 5px 6px;
+    font: inherit;
+    text-align: left;
+    cursor: pointer;
+}
+
+.nation-color-select-trigger {
+    min-height: 28px;
+}
+
+.nation-color-select-trigger:hover,
+.nation-color-select-trigger[aria-expanded='true'] {
+    border-color: rgba(244, 216, 153, 0.9);
+}
+
+.nation-color-select-trigger:focus-visible,
+.nation-color-select-option:focus-visible {
+    position: relative;
+    z-index: 1;
+    outline: 2px solid #fff;
+    outline-offset: -3px;
+}
+
+.nation-color-select-arrow {
+    margin-left: 8px;
+}
+
+.nation-color-select-options {
+    position: absolute;
+    z-index: 60;
+    top: calc(100% + 2px);
+    right: 0;
+    left: 0;
+    max-height: 240px;
+    overflow-y: auto;
+    border: 1px solid rgba(201, 164, 90, 0.7);
+    background: #111;
+    box-shadow: 0 5px 14px rgb(0 0 0 / 75%);
+}
+
+.nation-color-select-option {
+    min-height: 34px;
+    border: 0;
+    border-bottom: 1px solid rgb(0 0 0 / 30%);
+}
+
+.nation-color-select-option:hover,
+.nation-color-select-option[aria-selected='true'] {
+    box-shadow: inset 0 0 0 2px rgb(255 255 255 / 78%);
+}
+
+@media (max-width: 520px) {
+    .nation-color-select-options {
+        position: static;
+        margin-top: 2px;
+    }
+
+    .nation-color-select-option {
+        min-height: 44px;
+    }
+}
+</style>