diff --git a/package.json b/package.json
index 354dcc5..8bb26ec 100644
--- a/package.json
+++ b/package.json
@@ -19,6 +19,7 @@
     "vite-plugin-imagemin": "^0.6.1"
   },
   "dependencies": {
+    "gsap": "^3.15.0",
     "jquery": "^4.0.0",
     "sharp": "^0.35.1"
   }
diff --git a/src/index.html b/src/index.html
index 73c2fab..7dde23b 100644
--- a/src/index.html
+++ b/src/index.html
@@ -18,7 +18,7 @@
         </a>
         <nav class="gnb__nav">
           <ul class="gnb__navList">
-            <li class="gnb__navItem is-active"><a class="gnb__navLink" href="#intro">HOME</a></li>
+            <li class="gnb__navItem"><a class="gnb__navLink" href="#intro">HOME</a></li>
             <li class="gnb__navItem"><a class="gnb__navLink" href="#about">ABOUT</a></li>
             <li class="gnb__navItem"><a class="gnb__navLink" href="#project">PROJECTS</a></li>
             <li class="gnb__navItem"><a class="gnb__navLink" href="#contact">CONTACT</a></li>
@@ -638,7 +638,7 @@
         </div>
         <!-- 프로젝트 문의 -->
         <div class="contactAccordion">
-          <div class="contactAccordion__item is-open" id="acc-project">
+          <div class="contactAccordion__item isOpen" id="acc-project">
             <button class="contactAccordion__header" aria-expanded="true" aria-controls="acc-project-body">
               <span>프로젝트 문의</span>
               <img class="contactAccordion__icon" src="images/icon-chevron.svg" alt="" />
diff --git a/src/js/main.js b/src/js/main.js
index 217fa9d..4beae4f 100644
--- a/src/js/main.js
+++ b/src/js/main.js
@@ -1,55 +1,86 @@
 import $ from "jquery";
+import { gsap } from "gsap";
+import { ScrollTrigger } from "gsap/ScrollTrigger";
+
+gsap.registerPlugin(ScrollTrigger);
 
 $(function () {
   const $gnb = $("#gnb");
   const $hamburger = $(".gnb__hamburger");
   const $mobileNav = $(".gnb__mobileNav");
-  const $sections = $("section[id]");
-  const $navLinks = $(".gnb__navItem");
+
+  // 섹션 → nav 귀속 맵
+  const sectionToNav = {
+    intro: "intro",
+    about: "about",
+    history: "about",
+    "boda-intro": "about",
+    vision: "about",
+    project: "project",
+    expertise: "project",
+    contact: "contact",
+  };
 
   // GNB 스크롤 배경
-  $(window).on("scroll.gnb", { passive: true }, function () {
-    $gnb.toggleClass("is-scrolled", $(this).scrollTop() > 40);
-    updateActiveNav();
+  ScrollTrigger.create({
+    start: "40px top",
+    onEnter: () => $gnb.addClass("isScrolled"),
+    onLeaveBack: () => $gnb.removeClass("isScrolled"),
   });
 
+  // 현재 섹션에 따라 GNB 활성화
+  const $navLinks = $(".gnb__navLink");
+  const sections = $("section[id]").toArray();
+
+  function setActiveNav(navId) {
+    $navLinks.each(function () {
+      const href = $(this).attr("href").replace("#", "");
+      $(this).toggleClass("isActive", href === navId);
+    });
+  }
+
+  function updateActiveNav() {
+    const scrollY = window.scrollY + window.innerHeight / 3;
+    let current = "";
+
+    sections.forEach((el) => {
+      if (el.offsetTop <= scrollY) {
+        current = sectionToNav[el.id] || current;
+      }
+    });
+
+    setActiveNav(current);
+  }
+
+  ScrollTrigger.create({
+    trigger: document.body,
+    start: "top top",
+    end: "max",
+    onUpdate: updateActiveNav,
+  });
+
+  updateActiveNav();
+
   // 햄버거 메뉴
   $hamburger.on("click", function () {
-    const isOpen = $hamburger.toggleClass("is-open").hasClass("is-open");
+    const isOpen = $hamburger.toggleClass("isOpen").hasClass("isOpen");
     $hamburger.attr("aria-expanded", isOpen);
-    $mobileNav.toggleClass("is-open", isOpen);
+    $mobileNav.toggleClass("isOpen", isOpen);
   });
 
   // 모바일 메뉴 링크 클릭 시 닫기
   $(".gnb__mobileNavLink").on("click", function () {
-    $hamburger.removeClass("is-open").attr("aria-expanded", false);
-    $mobileNav.removeClass("is-open");
+    $hamburger.removeClass("isOpen").attr("aria-expanded", false);
+    $mobileNav.removeClass("isOpen");
   });
 
-  // 현재 섹션에 따라 GNB 활성화
-  function updateActiveNav() {
-    let current = "";
-    const scrollY = $(window).scrollTop() + $(window).height() / 3;
-
-    $sections.each(function () {
-      if ($(this).offset().top <= scrollY) {
-        current = $(this).attr("id");
-      }
-    });
-
-    $navLinks.each(function () {
-      const href = $(this).find("a").attr("href").replace("#", "");
-      $(this).toggleClass("is-active", href === current);
-    });
-  }
-
   // Contact 아코디언
   $(".contactAccordion__header").on("click", function () {
     const $item = $(this).closest(".contactAccordion__item");
     const $body = $("#" + $(this).attr("aria-controls"));
-    const isOpen = $item.hasClass("is-open");
+    const isOpen = $item.hasClass("isOpen");
 
-    $item.toggleClass("is-open", !isOpen);
+    $item.toggleClass("isOpen", !isOpen);
     $(this).attr("aria-expanded", !isOpen);
 
     if (isOpen) {
@@ -58,7 +89,4 @@ $(function () {
       $body.removeAttr("hidden");
     }
   });
-
-  // 초기 실행
-  updateActiveNav();
 });
diff --git a/src/scss/page/_contact.scss b/src/scss/page/_contact.scss
index a518524..096d22b 100644
--- a/src/scss/page/_contact.scss
+++ b/src/scss/page/_contact.scss
@@ -205,7 +205,7 @@
   object-fit: unset;
 }
 
-.contactAccordion__item.is-open .contactAccordion__icon {
+.contactAccordion__item.isOpen .contactAccordion__icon {
   transform: rotate(180deg);
 }
 
diff --git a/src/scss/page/_gnb.scss b/src/scss/page/_gnb.scss
index 6d901e2..767c9af 100644
--- a/src/scss/page/_gnb.scss
+++ b/src/scss/page/_gnb.scss
@@ -11,7 +11,7 @@
   z-index: 100;
   transition: background 0.4s;
 
-  &.is-scrolled {
+  &.isScrolled {
     background: rgba($color-bg, 0.92);
     backdrop-filter: blur(12px);
   }
@@ -63,7 +63,7 @@
   }
 }
 
-.gnb__navItem.is-active .gnb__navLink {
+.gnb__navLink.isActive {
   color: $color-cyan;
 }
 
@@ -90,13 +90,13 @@
     opacity 0.3s;
 }
 
-.gnb__hamburger.is-open .gnb__hamburgerLine:nth-child(1) {
+.gnb__hamburger.isOpen .gnb__hamburgerLine:nth-child(1) {
   transform: translateY(6px) rotate(45deg);
 }
-.gnb__hamburger.is-open .gnb__hamburgerLine:nth-child(2) {
+.gnb__hamburger.isOpen .gnb__hamburgerLine:nth-child(2) {
   opacity: 0;
 }
-.gnb__hamburger.is-open .gnb__hamburgerLine:nth-child(3) {
+.gnb__hamburger.isOpen .gnb__hamburgerLine:nth-child(3) {
   transform: translateY(-6px) rotate(-45deg);
 }
 
@@ -116,7 +116,7 @@
     opacity 0.35s ease;
   pointer-events: none;
 
-  &.is-open {
+  &.isOpen {
     transform: translateY(0);
     opacity: 1;
     pointer-events: auto;
diff --git a/vite.config.js b/vite.config.js
index 9396b8e..31b6660 100644
--- a/vite.config.js
+++ b/vite.config.js
@@ -29,6 +29,7 @@ export default defineConfig({
   plugins: [
     {
       name: 'remove-module-attrs',
+      apply: 'build',
       transformIndexHtml(html) {
         return html
           .replace(/ type="module"/g, '')