feat: complete ANL lab homepage with light/dark theme, responsive layout, and 100% SSG E2E test suite

refer_landing_page/tailwind.config.ts

@@ -21,6 +21,7 @@ import type { Config } from "tailwindcss";
  * Font CSS variables are injected by next/font in app/layout.tsx.
  */
 const config: Config = {
+  darkMode: ["class", '[data-theme="dark"]'],
   content: [
     "./app/**/*.{ts,tsx}",
     "./components/**/*.{ts,tsx}",
@@ -29,45 +30,54 @@ const config: Config = {
     extend: {
       colors: {
         ink: {
-          DEFAULT: "#0A0A0A",
-          soft: "#262420",
-          mute: "#6B655B",
+          DEFAULT: "rgb(var(--ink-rgb) / <alpha-value>)",
+          soft: "rgb(var(--ink-soft-rgb) / <alpha-value>)",
+          mute: "rgb(var(--ink-mute-rgb) / <alpha-value>)",
         },
-        ivory: "#F5F1E8",
-        paper: "#ECE6D6",
-        line: "#D8D1C0",
+        ivory: "rgb(var(--ivory-rgb) / <alpha-value>)",
+        paper: "rgb(var(--paper-rgb) / <alpha-value>)",
+        line: "rgb(var(--line-rgb) / <alpha-value>)",
         vermillion: {
-          DEFAULT: "#D9342B",
-          dark: "#A8231C",
+          DEFAULT: "rgb(var(--vermillion-rgb) / <alpha-value>)",
+          dark: "rgb(var(--vermillion-dark-rgb) / <alpha-value>)",
         },
         cobalt: {
-          DEFAULT: "#1B3A8A",
-          dark: "#122863",
+          DEFAULT: "rgb(var(--cobalt-rgb) / <alpha-value>)",
+          dark: "rgb(var(--cobalt-dark-rgb) / <alpha-value>)",
         },
         // Back-compat aliases so any stray legacy class still resolves.
         brand: {
-          DEFAULT: "#D9342B",
-          dark: "#A8231C",
-          light: "#1B3A8A",
+          DEFAULT: "rgb(var(--vermillion-rgb) / <alpha-value>)",
+          dark: "rgb(var(--vermillion-dark-rgb) / <alpha-value>)",
+          light: "rgb(var(--cobalt-rgb) / <alpha-value>)",
         },
-        accent: { DEFAULT: "#1B3A8A" },
+        accent: { DEFAULT: "rgb(var(--cobalt-rgb) / <alpha-value>)" },
       },
       fontFamily: {
         // English display serif — magazine cover scale.
         display: ["var(--font-display)", "Fraunces", "Georgia", "serif"],
         // Korean serif headlines.
         "serif-ko": ["var(--font-serif-ko)", "Noto Serif KR", "serif"],
-        // Clean sans body. Pretendard preferred, Inter as web fallback.
+        // Clean sans body. Geist preferred, Pretendard & Inter as web fallbacks.
         sans: [
-          "Pretendard",
+          "Geist",
           "var(--font-sans)",
+          "Pretendard",
           "Inter",
           "ui-sans-serif",
           "system-ui",
-          "Apple SD Gothic Neo",
-          "Malgun Gothic",
           "sans-serif",
         ],
+        mono: [
+          "Geist Mono",
+          "var(--font-mono)",
+          "ui-monospace",
+          "SFMono-Regular",
+          "Menlo",
+          "Monaco",
+          "Consolas",
+          "monospace",
+        ],
       },
       fontSize: {
         // Magazine-cover display scale. Capped at 7rem (was 9rem) so the