/* ==========================================================================
   1. DESIGN SYSTEM & CSS VARIABLES (WILMAR CLV COLOR PALETTE)
   ========================================================================== */
:root {
  /* Tông màu xanh lá nhận diện thương hiệu Wilmar Marketing CLV */
  --color-primary: #007A3D;        /* Xanh lá chủ đạo của Wilmar */
  --color-primary-dark: #004D25;   /* Xanh lá đậm chiều sâu, sang trọng */
  --color-primary-light: #EAF5EE;  /* Xanh lá non nhạt cho badge, active card */
  --color-primary-hover: #088F4A;  /* Xanh lá tươi khi di chuột */
  --color-accent: #2CA544;         /* Xanh lá tươi điểm nhấn */
  
  --color-bg: #F4F9F5;             /* Nền website ánh xanh ngọc mát mắt theo poster */
  --color-surface: #FFFFFF;        /* Nền thẻ trắng tinh khiết */
  --color-surface-alt: #ECF5EF;    /* Nền phụ dịu nhẹ */
  
  --color-text-main: #13261C;      /* Chữ đậm sắc sảo, tương phản cao, dễ đọc */
  --color-text-muted: #4B6354;     /* Chữ phụ xám rêu hài hòa */
  --color-text-light: #7E9687;     /* Chữ chú thích nhạt */
  
  --color-border: #CFE5D6;         /* Viền xanh nhạt trang nhã */
  --color-border-subtle: #DFEDE3;  /* Viền ngăn cách nhẹ */
  
  --shadow-sm: 0 1px 3px rgba(0, 77, 37, 0.05), 0 1px 2px rgba(0, 77, 37, 0.03);
  --shadow-md: 0 4px 14px rgba(0, 122, 61, 0.08);
  --shadow-lg: 0 10px 25px -5px rgba(0, 122, 61, 0.12), 0 8px 10px -6px rgba(0, 122, 61, 0.06);

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-pill: 9999px;

  --header-height: 70px;
  --top-nav-height: 56px;
  --container-max: 1200px;
  
  --transition-fast: 0.18s ease;
  --transition-normal: 0.25s ease;
}

/* ==========================================================================
   2. RESET & BASE STYLES
   ========================================================================== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background-color: var(--color-bg);
  color: var(--color-text-main);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  color: inherit;
  text-decoration: none;
}

ul {
  list-style: none;
}

/* ==========================================================================
   3. SITE HEADER
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm);
  height: var(--header-height);
}

.header-container {
  max-width: var(--container-max);
  height: 100%;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  display: flex;
  align-items: center;
  gap: 14px;
}

.brand-icon {
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  color: #FFFFFF;
  border-radius: var(--radius-md);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1.25rem;
  box-shadow: 0 2px 6px rgba(0, 122, 61, 0.25);
}

.brand-logo {
  height: 44px;
  width: auto;
  max-width: 150px;
  object-fit: contain;
  display: block;
}

.brand-text h1 {
  font-size: 1.15rem;
  font-weight: 800;
  letter-spacing: 0.02em;
  color: var(--color-primary-dark);
  line-height: 1.2;
}

.brand-text p {
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

.header-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--color-primary-light);
  color: var(--color-primary);
  font-size: 0.82rem;
  font-weight: 600;
  padding: 6px 14px;
  border-radius: var(--radius-pill);
  border: 1px solid rgba(0, 122, 61, 0.18);
}

/* ==========================================================================
   4. TOP CATEGORY NAVIGATION (MENU NGANG PHÍA TRÊN)
   ========================================================================== */
.top-nav-bar {
  position: sticky;
  top: var(--header-height);
  z-index: 95;
  background-color: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-border);
  box-shadow: 0 4px 14px rgba(0, 77, 37, 0.05);
  display: flex;
  align-items: center;
  position: sticky;
}

.top-nav-container {
  flex: 1;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 10px 16px;
  overflow-x: auto;
  scrollbar-width: none;
  -ms-overflow-style: none;
  -webkit-overflow-scrolling: touch;
  scroll-behavior: smooth;
  cursor: grab;
  user-select: none;
}

.top-nav-container.is-dragging {
  cursor: grabbing;
  scroll-behavior: auto;
}

.top-nav-container::-webkit-scrollbar {
  display: none;
}

.nav-list {
  display: flex;
  align-items: center;
  justify-content: flex-start;
  gap: 10px;
  margin: 0;
  padding: 2px 0;
  width: max-content;
}



.nav-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  border-radius: var(--radius-pill);
  color: var(--color-text-main);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  font-size: 0.92rem;
  font-weight: 600;
  white-space: nowrap;
  text-decoration: none;
  transition: all var(--transition-fast);
  cursor: pointer;
  box-shadow: var(--shadow-sm);
}

.nav-icon {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--color-surface-alt);
  color: var(--color-primary);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 0.95rem;
  flex-shrink: 0;
  border: 1px solid var(--color-border-subtle);
  transition: transform var(--transition-fast), background-color var(--transition-fast);
}

.nav-text {
  white-space: nowrap;
}

/* Hover effect */
.nav-link:hover {
  background-color: var(--color-primary-light);
  color: var(--color-primary-dark);
  border-color: rgba(0, 122, 61, 0.35);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.nav-link:hover .nav-icon {
  background: #FFFFFF;
  transform: scale(1.1);
  border-color: rgba(0, 122, 61, 0.3);
}

/* Active State */
.nav-link.active {
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  color: #FFFFFF;
  border-color: var(--color-primary-dark);
  font-weight: 600;
  box-shadow: 0 4px 14px rgba(0, 122, 61, 0.3);
}

.nav-link.active .nav-icon {
  background: rgba(255, 255, 255, 0.22);
  color: #FFFFFF;
  border-color: transparent;
  transform: scale(1.05);
  animation: iconPulse 0.45s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.nav-link:active {
  transform: scale(0.93) translateY(0);
}

.nav-link.clicked {
  animation: navPillPop 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
}

@keyframes navPillPop {
  0% { transform: scale(0.92); }
  50% { transform: scale(1.06); }
  100% { transform: scale(1); }
}

@keyframes iconPulse {
  0% { transform: scale(0.85); }
  60% { transform: scale(1.22); }
  100% { transform: scale(1.05); }
}

/* ==========================================================================
   5. MAIN WRAPPER & NỘI DUNG SẢN PHẨM
   ========================================================================== */
.app-container {
  max-width: var(--container-max);
  margin: 28px auto 60px;
  padding: 0 20px;
}

.content-area {
  display: flex;
  flex-direction: column;
  gap: 32px;
  min-width: 0;
  width: 100%;
}

.category-section {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition-normal), border-color var(--transition-normal), transform var(--transition-normal);
  scroll-margin-top: calc(var(--header-height) + var(--top-nav-height) + 18px);
  position: relative;
}

.category-section:hover {
  box-shadow: var(--shadow-md);
  border-color: #A6D7B6;
}

/* Hiệu ứng chuyển động & phát sáng khi chọn nhóm sản phẩm */
.category-section.section-highlight {
  animation: sectionFocusGlow 1.25s cubic-bezier(0.22, 1, 0.36, 1);
  border-color: var(--color-primary);
}

@keyframes sectionFocusGlow {
  0% {
    box-shadow: 0 0 0 0 rgba(0, 122, 61, 0.5);
    border-color: var(--color-primary);
    transform: scale(0.995);
  }
  28% {
    box-shadow: 0 12px 32px rgba(0, 122, 61, 0.22), 0 0 0 5px rgba(44, 165, 68, 0.35);
    border-color: var(--color-primary);
    transform: translateY(-4px);
  }
  100% {
    box-shadow: var(--shadow-sm);
    border-color: var(--color-border);
    transform: translateY(0);
  }
}

.category-section.section-highlight .section-badge-icon {
  animation: badgePopSpin 0.9s cubic-bezier(0.34, 1.56, 0.64, 1);
}

@keyframes badgePopSpin {
  0% { transform: scale(1) rotate(0deg); }
  35% { transform: scale(1.25) rotate(-12deg); background-color: var(--color-primary); color: #FFFFFF; }
  70% { transform: scale(1.1) rotate(6deg); }
  100% { transform: scale(1) rotate(0deg); }
}

.section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--color-border-subtle);
  padding-bottom: 18px;
  margin-bottom: 20px;
  flex-wrap: wrap;
  gap: 12px;
}

.section-title-wrap {
  display: flex;
  align-items: center;
  gap: 14px;
}

.section-badge-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  background: var(--color-primary-light);
  color: var(--color-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.35rem;
  border: 1px solid rgba(0, 122, 61, 0.18);
  flex-shrink: 0;
}

.section-title {
  font-size: 1.45rem;
  font-weight: 700;
  color: var(--color-primary-dark);
  line-height: 1.3;
}

.section-order-badge {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--color-primary);
  background: var(--color-primary-light);
  padding: 4px 10px;
  border-radius: var(--radius-pill);
  border: 1px solid rgba(0, 122, 61, 0.15);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.section-description {
  font-size: 1.02rem;
  color: var(--color-text-main);
  background: var(--color-surface-alt);
  padding: 16px 20px;
  border-radius: var(--radius-md);
  border-left: 4px solid var(--color-primary);
  margin-bottom: 24px;
  line-height: 1.65;
}

.section-description p + p {
  margin-top: 10px;
}

/* Lưới các thẻ sản phẩm mẫu */
.sample-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 16px;
}

.sample-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-md);
  padding: 18px;
  transition: transform var(--transition-fast), 
              box-shadow var(--transition-fast), 
              border-color var(--transition-fast);
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.sample-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
  border-color: var(--color-primary);
}

.card-tag {
  align-self: flex-start;
  font-size: 0.72rem;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 4px;
  background: var(--color-primary-light);
  color: var(--color-primary);
}

.card-title {
  font-size: 0.98rem;
  font-weight: 600;
  color: var(--color-primary-dark);
}

.card-desc {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  line-height: 1.5;
}

/* ==========================================================================
   CATEGORY QR BANNER (KHUNG MÃ QR CĂN GIỮA)
   ========================================================================== */
.category-qr-banner {
  margin-top: 26px;
  display: flex;
  justify-content: center;
  align-items: center;
  text-align: center;
}

.category-qr-banner a {
  display: inline-block;
  line-height: 0;
  border-radius: var(--radius-md);
}

.category-qr-img {
  max-width: 250px;
  width: 100%;
  height: auto;
  display: block;
  margin: 0 auto;
  border-radius: var(--radius-md);
  box-shadow: 0 4px 14px rgba(0, 77, 37, 0.1);
  border: 1px solid var(--color-border);
  transition: transform var(--transition-normal), box-shadow var(--transition-normal), border-color var(--transition-normal);
}

.category-qr-banner a:hover .category-qr-img {
  transform: translateY(-3px);
  box-shadow: 0 8px 22px rgba(0, 122, 61, 0.2);
  border-color: var(--color-primary);
}

/* ==========================================================================
   INTRO GALLERY (LƯỚI HÌNH ẢNH GIỚI THIỆU: 4 CỘT X 3 HÀNG)
   ========================================================================== */
.intro-gallery-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin-top: 8px;
}

/* Lưới dàn hàng ngang tối đa 3 cột: Tự động căn giữa khi có 1, 2 hoặc 3 hình ảnh */
.intro-gallery-grid.gallery-grid-3 {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 20px;
}

.intro-gallery-grid.gallery-grid-3 .intro-gallery-item {
  flex: 0 0 calc((100% - 40px) / 3);
  max-width: calc((100% - 40px) / 3);
  min-width: 260px;
}

@media (max-width: 992px) {
  .intro-gallery-grid.gallery-grid-3 .intro-gallery-item {
    flex: 0 0 calc((100% - 20px) / 2);
    max-width: calc((100% - 20px) / 2);
  }
}

@media (max-width: 600px) {
  .intro-gallery-grid.gallery-grid-3 .intro-gallery-item {
    flex: 0 0 100%;
    max-width: 100%;
  }
}

.intro-gallery-item {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-normal), box-shadow var(--transition-normal), border-color var(--transition-normal);
  aspect-ratio: 1 / 1.414; /* Tỷ lệ khổ giấy A4 chuẩn của Brochure / Catalog */
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  cursor: pointer;
}

.intro-gallery-item:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: var(--color-primary);
}

.intro-img {
  width: 100%;
  height: 100%;
  object-fit: contain; /* Giữ trọn vẹn 100% hình ảnh gốc, không bị cắt xén phía trên hay phía dưới */
  display: block;
  transition: transform var(--transition-normal);
  cursor: zoom-in;
}

.intro-gallery-item::after {
  content: "🔍 Phóng to";
  position: absolute;
  bottom: 8px;
  right: 8px;
  background: rgba(0, 0, 0, 0.65);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  color: #FFFFFF;
  font-size: 0.72rem;
  font-weight: 500;
  padding: 3px 8px;
  border-radius: 4px;
  opacity: 0;
  transform: translateY(6px);
  transition: all var(--transition-fast);
  pointer-events: none;
}

.intro-gallery-item:hover::after {
  opacity: 1;
  transform: translateY(0);
}

.intro-gallery-item:hover .intro-img {
  transform: scale(1.03);
}

/* ==========================================================================
   POPUP LIGHTBOX HIỂN THỊ HÌNH ẢNH GỐC SẮC NÉT
   ========================================================================== */
.lightbox-modal {
  position: fixed;
  inset: 0;
  z-index: 9999;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.28s ease, visibility 0.28s ease;
}

.lightbox-modal.active {
  opacity: 1;
  visibility: visible;
}

.lightbox-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(10, 24, 16, 0.88);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}

.lightbox-content {
  position: relative;
  z-index: 2;
  width: 95vw;
  max-width: 1100px;
  height: 90vh;
  display: flex;
  flex-direction: column;
  background: #14241B;
  border: 1px solid rgba(110, 224, 168, 0.25);
  border-radius: var(--radius-lg);
  box-shadow: 0 25px 60px rgba(0, 0, 0, 0.55);
  overflow: hidden;
  animation: lightboxScaleUp 0.3s cubic-bezier(0.2, 0.9, 0.3, 1);
}

@keyframes lightboxScaleUp {
  0% { transform: scale(0.92); opacity: 0; }
  100% { transform: scale(1); opacity: 1; }
}

.lightbox-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 18px;
  background: rgba(0, 0, 0, 0.4);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  color: #FFFFFF;
}

.lightbox-title {
  font-size: 0.96rem;
  font-weight: 600;
  color: #E2F5EA;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.lightbox-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

.lightbox-btn {
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.15);
  color: #FFFFFF;
  width: 36px;
  height: 36px;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.lightbox-btn:hover {
  background: var(--color-primary);
  border-color: var(--color-primary);
  transform: scale(1.08);
}

.lightbox-close:hover {
  background: #E53935;
  border-color: #E53935;
}

.lightbox-body {
  flex: 1;
  overflow: auto;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  padding: 16px;
  background: #0B1710;
}

.lightbox-img {
  max-width: 100%;
  max-height: 100%;
  object-fit: contain;
  border-radius: 4px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.4);
  transition: transform 0.2s cubic-bezier(0.2, 0.9, 0.3, 1), opacity 0.25s ease;
  transform-origin: center center;
  user-select: none;
}

/* Spinner quay nạp ảnh */
.lightbox-spinner {
  position: absolute;
  width: 44px;
  height: 44px;
  border: 3px solid rgba(110, 224, 168, 0.2);
  border-top-color: #6EE0A8;
  border-radius: 50%;
  animation: spinnerRotate 0.8s linear infinite;
  display: none;
}

@keyframes spinnerRotate {
  to { transform: rotate(360deg); }
}

/* Nút bấm chuyển ảnh Prev / Next */
.lightbox-nav-btn {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  background: rgba(20, 36, 27, 0.85);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  border: 1px solid rgba(110, 224, 168, 0.3);
  color: #FFFFFF;
  width: 46px;
  height: 46px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  z-index: 10;
  transition: all var(--transition-fast);
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.4);
}

.lightbox-prev {
  left: 14px;
}

.lightbox-next {
  right: 14px;
}

.lightbox-nav-btn:hover {
  background: var(--color-primary);
  border-color: var(--color-primary);
  transform: translateY(-50%) scale(1.12);
}

@media (max-width: 768px) {
  .lightbox-content {
    width: 98vw;
    height: 94vh;
    border-radius: var(--radius-md);
  }

  .lightbox-nav-btn {
    width: 38px;
    height: 38px;
  }

  .lightbox-prev {
    left: 8px;
  }

  .lightbox-next {
    right: 8px;
  }

  .lightbox-title {
    font-size: 0.85rem;
  }
}


@media (max-width: 992px) {
  .intro-gallery-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 14px;
  }
}

@media (max-width: 640px) {
  .intro-gallery-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
  }
}

@media (max-width: 400px) {
  .intro-gallery-grid {
    grid-template-columns: 1fr;
  }
}


@media (max-width: 480px) {
  .category-qr-img {
    max-width: 210px;
  }
}

/* ==========================================================================
   7. FOOTER
   ========================================================================== */
.site-footer {
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: 28px 20px;
  margin-top: 40px;
  text-align: center;
  color: var(--color-text-muted);
  font-size: 0.88rem;
}

.footer-container {
  max-width: var(--container-max);
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

.footer-logo {
  height: 48px;
  width: auto;
  max-width: 160px;
  object-fit: contain;
  margin-bottom: 4px;
  display: block;
}

.back-to-top {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--color-primary);
  font-weight: 600;
  cursor: pointer;
  margin-top: 6px;
  transition: opacity var(--transition-fast);
}

.back-to-top:hover {
  opacity: 0.8;
  text-decoration: underline;
}

/* ==========================================================================
   FLOATING SCROLL TO TOP BUTTON (NÚT LÊN ĐẦU TRANG)
   ========================================================================== */
.scroll-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background: linear-gradient(135deg, #1EA754, #007A3D);
  color: #FFFFFF;
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 8px 24px rgba(0, 122, 61, 0.35);
  z-index: 999;
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px) scale(0.9);
  transition: opacity 0.3s cubic-bezier(0.4, 0, 0.2, 1),
              transform 0.3s cubic-bezier(0.4, 0, 0.2, 1),
              visibility 0.3s cubic-bezier(0.4, 0, 0.2, 1),
              box-shadow 0.25s ease,
              background 0.25s ease;
  outline: none;
}

/* Vòng sóng radar tỏa xung quanh nút khi hiển thị */
.scroll-to-top::after {
  content: "";
  position: absolute;
  inset: -3px;
  border-radius: 50%;
  border: 2px solid rgba(44, 165, 68, 0.6);
  opacity: 0;
  pointer-events: none;
}

.scroll-to-top.show::after {
  animation: radarRing 2.6s infinite cubic-bezier(0.22, 1, 0.36, 1);
}

@keyframes radarRing {
  0% { transform: scale(0.95); opacity: 0.85; }
  50% { transform: scale(1.4); opacity: 0; }
  100% { transform: scale(1.4); opacity: 0; }
}

.scroll-to-top.show {
  opacity: 1;
  visibility: visible;
  transform: translateY(0) scale(1);
}

.scroll-to-top:hover {
  background: linear-gradient(135deg, #24BA5E, #006633);
  transform: translateY(-4px) scale(1.08);
  box-shadow: 0 14px 30px rgba(0, 122, 61, 0.45);
}

.scroll-to-top:active {
  transform: translateY(0) scale(0.95);
  box-shadow: 0 4px 12px rgba(0, 122, 61, 0.25);
}

.scroll-to-top svg {
  display: block;
  transition: transform 0.2s ease;
}

.scroll-to-top:hover svg {
  transform: translateY(-3px);
}

/* Hiệu ứng phóng vút lên đầu trang (Rocket Launch Animation) */
.scroll-to-top.launching {
  animation: rocketLaunch 0.75s cubic-bezier(0.22, 1, 0.36, 1) forwards;
}

@keyframes rocketLaunch {
  0% {
    transform: translateY(0) scale(0.92);
  }
  35% {
    transform: translateY(-14px) scale(1.2);
    box-shadow: 0 20px 40px rgba(0, 122, 61, 0.6), 0 0 25px rgba(44, 165, 68, 0.7);
    background: linear-gradient(135deg, #2CD96D, #008F48);
  }
  70% {
    transform: translateY(-28px) scale(1.05);
    opacity: 0.85;
  }
  100% {
    transform: translateY(0) scale(1);
    opacity: 1;
  }
}

.scroll-to-top.launching svg {
  animation: arrowFlyUp 0.75s cubic-bezier(0.22, 1, 0.36, 1);
}

@keyframes arrowFlyUp {
  0% { transform: translateY(0); }
  45% { transform: translateY(-8px); }
  100% { transform: translateY(0); }
}

/* ==========================================================================
   8. RESPONSIVE DESIGN
   ========================================================================== */
/* Tablet (< 992px) */
@media (max-width: 992px) {
  .app-container {
    margin-top: 20px;
    padding: 0 16px;
  }

  .nav-list {
    justify-content: flex-start;
  }

  .category-section {
    padding: 24px;
  }

  .section-title {
    font-size: 1.25rem;
  }
}

/* Mobile (< 768px) */
@media (max-width: 768px) {
  :root {
    --header-height: 62px;
    --top-nav-height: 48px;
  }

  .app-container {
    padding: 0 14px;
    margin-top: 16px;
  }

  .top-nav-container {
    padding: 6px 14px;
  }

  .nav-list {
    gap: 8px;
    justify-content: flex-start;
  }

  .nav-link {
    padding: 6px 12px;
    font-size: 0.85rem;
  }

  .nav-icon {
    width: 24px;
    height: 24px;
    font-size: 0.88rem;
  }

  .category-section {
    padding: 20px 16px;
    scroll-margin-top: calc(var(--header-height) + var(--top-nav-height) + 14px);
  }

  .section-title {
    font-size: 1.15rem;
  }

  .section-badge-icon {
    width: 36px;
    height: 36px;
    font-size: 1.15rem;
  }

  .section-description {
    font-size: 0.92rem;
    padding: 12px 14px;
  }

  .sample-grid {
    grid-template-columns: 1fr;
  }

  .scroll-to-top {
    bottom: 20px;
    right: 20px;
    width: 44px;
    height: 44px;
  }
}