/* ============================================================
   ROOT VARIABLES – chỉnh sửa tại đây để thay đổi toàn bộ site
   ============================================================ */
:root {
  /* ----- MÀU SẮC CHÍNH ----- */
  --clr-primary: #1BAB9A;
  --clr-primary-dark: #15887A;
  --clr-primary-light: #26C7B4;
  --clr-primary-bg: #E6F7F5;

  /* ----- MÀU VĂN BẢN & NỀN ----- */
  --clr-text: #2D2D2D;
  --clr-text-muted: #666666;
  --clr-text-light: #999999;
  --clr-white: #FFFFFF;
  --clr-bg: #FFFFFF;
  --clr-bg-off: #F8FAFA;

  /* ----- MÀU WORKSHOP / CARD ----- */
  --clr-workshop-text: #FFFFFF;
  --clr-card-light-bg: #2BBFAD;
  --clr-card-dark-bg: #1A7A70;
  --clr-card-text: #FFFFFF;

  /* ----- GRADIENT ----- */
  --gradient-primary: linear-gradient(135deg, #1BAB9A 0%, #15887A 100%);
  --gradient-primary-hover: linear-gradient(135deg, #26C7B4 0%, #1BAB9A 100%);
  --gradient-hero-overlay: linear-gradient(90deg, rgba(0, 0, 0, 0.78) 0%, rgba(0, 0, 0, 0.25) 100%);
  --gradient-footer: linear-gradient(135deg, #1BAB9A 0%, #14766A 100%);

  /* ----- TYPOGRAPHY ----- */
  --font-family: 'Montserrat';

  --fs-xs: 0.72rem;
  --fs-sm: 0.875rem;
  --fs-base: 1rem;
  --fs-md: 1.125rem;
  --fs-lg: 1.25rem;
  --fs-xl: 1.5rem;
  --fs-2xl: 2rem;
  --fs-3xl: 2.5rem;
  --fs-4xl: 3rem;
  --fs-5xl: 3.75rem;

  --fw-light: 300;
  --fw-regular: 400;
  --fw-medium: 500;
  --fw-semibold: 600;
  --fw-bold: 700;
  --fw-extrabold: 800;

  --lh-tight: 1.2;
  --lh-snug: 1.4;
  --lh-base: 1.65;

  /* ----- SPACING ----- */
  --section-py: 120px;
  --section-py-sm: 80px;
  --container-max: 1200px;
  --container-px: 40px;

  /* ----- BORDER RADIUS ----- */
  --radius-xs: 4px;
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 22px;
  --radius-xl: 32px;
  --radius-full: 9999px;

  /* ----- SHADOW ----- */
  --shadow-xs: 0 1px 4px rgba(0, 0, 0, 0.07);
  --shadow-sm: 0 2px 10px rgba(0, 0, 0, 0.09);
  --shadow-md: 0 4px 24px rgba(0, 0, 0, 0.12);
  --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.16);
  --shadow-primary: 0 6px 28px rgba(27, 171, 154, 0.38);

  /* ----- TRANSITION ----- */
  --transition-fast: 0.18s ease;
  --transition-base: 0.28s ease;
  --transition-slow: 0.48s cubic-bezier(0.25, 0.8, 0.25, 1);

  /* ----- HEADER ----- */
  --nav-height: 72px;
  --nav-bg: rgba(255, 255, 255, 0.97);
  --nav-shadow: 0 2px 20px rgba(0, 0, 0, 0.08);

  /* ----- BUTTON ----- */
  --btn-py: 0.7rem;
  --btn-px: 1.6rem;
  --btn-radius: var(--radius-full);
  --btn-font-size: 0.9rem;
  --btn-font-weight: var(--fw-semibold);

  /* ----- MOBILE OPTIMIZATION ----- */
  --fs-h1: clamp(2.5rem, 8vw, 5rem);
  --fs-h2: clamp(2rem, 6vw, 3.5rem);
  --fs-h3: clamp(1.5rem, 5vw, 2.25rem);
  --fs-body: clamp(0.9rem, 2vw, 1rem);
}


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

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

body {
  font-family: var(--font-family);
  font-size: var(--fs-base);
  font-weight: var(--fw-regular);
  line-height: var(--lh-base);
  color: var(--clr-text);
  background: var(--clr-bg);
  -webkit-font-smoothing: antialiased;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

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

ul {
  list-style: none;
}

button {
  cursor: pointer;
  border: none;
  background: none;
  font-family: inherit;
}


/* ============================================================
   UTILITIES
   ============================================================ */
.container {
  max-width: var(--container-max);
  width: 100%;
  margin: 0 auto;
  padding: 0 var(--container-px);
}

.section {
  padding-block: 4rem;
  /* Giảm từ 6rem xuống 4rem để các phần gần nhau hơn */
}

/* Fade-in on scroll */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}


/* ============================================================
   BUTTONS
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: var(--btn-py) var(--btn-px);
  border-radius: var(--btn-radius);
  font-size: var(--btn-font-size);
  font-weight: var(--btn-font-weight);
  font-family: var(--font-family);
  transition: all var(--transition-base);
  white-space: nowrap;
}

.btn--primary {
  background: var(--gradient-primary);
  color: var(--clr-white);
  box-shadow: var(--shadow-primary);
}

.btn--primary:hover {
  background: var(--gradient-primary-hover);
  box-shadow: 0 8px 36px rgba(27, 171, 154, 0.48);
  transform: translateY(-2px);
}

.btn--workshop {
  background: var(--clr-white);
  color: var(--clr-primary);
  font-weight: var(--fw-bold);
  padding: 0.6rem 1.4rem;
  border-radius: var(--radius-full);
}

.btn--workshop:hover {
  background: var(--clr-primary-bg);
  transform: translateY(-2px);
}

.btn__dot {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--clr-primary);
  flex-shrink: 0;
}


/* ============================================================
   HEADER / NAV
   ============================================================ */
.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  background: var(--nav-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  box-shadow: 0 1px 0 rgba(0, 0, 0, 0.05);
  transition: all var(--transition-base);
  height: var(--nav-height);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  height: var(--nav-height);
}

.nav__logo img {
  height: 60px;
  width: auto;
}

.nav__menu {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.nav__link {
  font-size: var(--fs-base);
  font-weight: var(--fw-medium);
  color: var(--clr-text);
  padding: 0.5rem 0;
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.nav__link.underline {
  border-bottom: 2px solid transparent;
  padding-bottom: 2px;
}

.nav__link.underline:hover {
  border-bottom-color: var(--clr-text);
}

.nav__link--active {
  background: var(--clr-primary);
  color: var(--clr-white) !important;
  padding: 0.6rem 1.4rem;
  border-radius: var(--radius-full);
  font-weight: var(--fw-semibold);
}

.nav__icon-cursor {
  stroke: var(--clr-white);
  transform: translateY(2px);
}

.nav__separator {
  width: 1px;
  height: 24px;
  background: #E0E0E0;
  margin: 0 0.5rem;
}

.nav__btn-menu {
  display: none;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 1rem;
  border: 1.5px solid var(--clr-primary);
  border-radius: var(--radius-full);
  font-size: var(--fs-sm);
  font-weight: var(--fw-bold);
  color: var(--clr-primary);
  background: transparent;
  transition: all var(--transition-base);
  z-index: 2001;
}

.nav__btn-menu:hover {
  background: var(--clr-primary);
  color: var(--clr-white);
}

.nav__btn-menu.open {
  border-color: transparent;
  color: var(--clr-text);
  background: rgba(0, 0, 0, 0.05);
}

.nav__icon-burger {
  opacity: 0.8;
}

.nav__overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.4);
  backdrop-filter: blur(4px);
  z-index: 1900;
  opacity: 0;
  visibility: hidden;
  transition: all 0.4s ease;
}

.nav__overlay.open {
  opacity: 1;
  visibility: visible;
}

/* --- Dropdown Menu --- */
.nav__item.dropdown {
  position: relative;
}

.dropdown-menu {
  position: absolute;
  top: 100%;
  left: 0;
  background: var(--clr-white);
  min-width: 200px;
  border-radius: var(--radius-md);
  padding: 0.75rem 0;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: all var(--transition-base);
  border: 1px solid rgba(0, 0, 0, 0.05);
  z-index: 100;
}

.nav__item.dropdown:hover .dropdown-menu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.dropdown-item {
  display: block;
  padding: 0.6rem 1.5rem;
  font-size: var(--fs-sm);
  font-weight: var(--fw-medium);
  color: var(--clr-text);
  transition: all var(--transition-fast);
}

.dropdown-item:hover {
  background: var(--clr-primary-bg);
  color: var(--clr-primary);
  padding-left: 1.8rem;
}

.dropdown__icon {
  transition: transform var(--transition-fast);
  opacity: 0.6;
}

.nav__item.dropdown:hover .dropdown__icon {
  transform: rotate(180deg);
}

@media (max-width: 768px) {
  .dropdown-menu {
    position: static;
    opacity: 1;
    visibility: visible;
    transform: none;
    box-shadow: none;
    background: rgba(0, 0, 0, 0.03);
    border-radius: var(--radius-sm);
    margin: 0.5rem 1.5rem;
    display: none;
  }

  .nav__item.dropdown.active .dropdown-menu {
    display: block;
  }

  .dropdown-item {
    padding: 0.8rem 1.2rem;
  }
}


/* ============================================================
   HERO
   ============================================================ */
.hero {
  padding: var(--section-py) 0;
  text-align: center;
  background: radial-gradient(circle at top right, rgba(27, 171, 154, 0.05), transparent),
    radial-gradient(circle at bottom left, rgba(27, 171, 154, 0.03), transparent);
}

.hero__content {
  max-width: 900px;
  margin: 0 auto;
}

.hero__title {
  font-size: var(--fs-h1);
  font-weight: var(--fw-extrabold);
  line-height: 1.1;
  color: #111;
  margin-bottom: 1.5rem;
  letter-spacing: -0.03em;
}

.hero__quote {
  font-size: clamp(1.1rem, 4vw, 1.8rem);
  color: var(--clr-text-muted);
  margin-bottom: 1.5rem;
  letter-spacing: 0.01em;
  font-weight: var(--fw-medium);
}

.hero__tagline {
  font-size: clamp(1rem, 3vw, 1.5rem);
  font-weight: var(--fw-bold);
  color: var(--clr-primary);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}


/* ============================================================
   WORKSHOP SLIDER
   ============================================================ */
.workshop {
  position: relative;
  height: auto !important;
  /* Để chiều cao tự động co giãn theo nội dung */
  min-height: 700px;
  padding-top: calc(var(--nav-height) + 40px);
  /* Bù đắp menu và thêm 40px trống phía trên */
  padding-bottom: 60px;
  /* Thêm 60px trống phía dưới */
  overflow: hidden;
  background: #000;
}

.workshop__track {
  position: relative;
  width: 100%;
  height: 100%;
}

.workshop__slide {
  position: absolute;
  inset: 0;
  opacity: 0;
  visibility: hidden;
  transition: opacity 1s cubic-bezier(0.4, 0, 0.2, 1), visibility 1s;
  display: flex;
  align-items: center;
  height: 100%;
}

/* Khi chỉ có 1 slide hoặc muốn slide đầu tiên tự đẩy chiều cao */
.workshop__slide.active {
  position: relative !important;
  /* Chuyển sang relative để đẩy chiều cao cho Section */
  opacity: 1;
  visibility: visible;
  height: auto !important;
}

.workshop__bg {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center;
  transform: scale(1.1);
  transition: transform 12s ease;
}

.workshop__slide.active .workshop__bg {
  transform: scale(1);
}

.workshop__overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(90deg,
      rgba(0, 0, 0, 0.9) 0%,
      rgba(0, 0, 0, 0.6) 50%,
      rgba(0, 0, 0, 0.3) 100%);
}

.workshop__inner {
  position: relative;
  z-index: 5;
  width: 100%;
  padding-top: 60px;
  /* Tạo khoảng cách an toàn phía trên */
  padding-bottom: 60px;
  /* Tạo khoảng cách an toàn phía dưới */
}

.workshop__text {
  max-width: 720px;
  padding: 3.5rem;
  background: rgba(0, 0, 0, 0.55);
  /* Làm tối hơn để nổi bật chữ trắng trên desktop */
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid rgba(255, 255, 255, 0.15);
  border-radius: var(--radius-xl);
  transform: translateX(-40px);
  opacity: 0;
  transition: all 1s cubic-bezier(0.2, 0.8, 0.2, 1);
  transition-delay: 0.3s;
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
  /* Thêm đổ bóng sâu cho khối text */
}

.workshop__slide.active .workshop__text {
  transform: translateX(0);
  opacity: 1;
}

.workshop__label {
  display: inline-block;
  font-size: var(--fs-xs);
  font-weight: var(--fw-bold);
  color: var(--clr-primary);
  text-transform: uppercase;
  letter-spacing: 0.15em;
  margin-bottom: 1.25rem;
  padding: 0.4rem 1rem;
  background: rgba(27, 171, 154, 0.1);
  border-radius: var(--radius-full);
}

.workshop__title {
  font-size: clamp(var(--fs-2xl), 5vw, var(--fs-4xl));
  font-weight: var(--fw-extrabold);
  color: var(--clr-white);
  line-height: 1.1;
  margin-bottom: 1.5rem;
  letter-spacing: -0.02em;
}

.workshop__description {
  font-size: 1rem;
  /* Giảm từ var(--fs-md) xuống 16px */
  color: rgba(255, 255, 255, 0.8);
  line-height: 1.6;
  margin-bottom: 2rem;
  border-left: 3px solid var(--clr-primary);
  padding-left: 1.5rem;
}

.workshop__list {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem 2rem;
  margin-bottom: 2.5rem;
}

.workshop__list li {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  font-size: var(--fs-sm);
  color: rgba(255, 255, 255, 0.9);
  line-height: 1.4;
  transition: all var(--transition-fast);
}

.workshop__list-item--featured {
  background: rgba(255, 215, 0, 0.15);
  /* Nền vàng hổ phách mờ */
  color: #ffcc00 !important;
  /* Chữ vàng sáng đậm màu */
  font-weight: var(--fw-bold);
  padding: 0.6rem 0.8rem;
  border-radius: 8px;
  border-left: 3px solid #ffcc00;
  /* Vạch kẻ nổi bật phía bên trái */
  animation: pulse-featured 3s infinite;
  /* Hiệu ứng nhịp đập thu hút ánh nhìn */
  box-shadow: 0 0 15px rgba(255, 204, 0, 0.2);
}

@keyframes pulse-featured {
  0% {
    transform: scale(1);
    box-shadow: 0 0 5px rgba(255, 204, 0, 0.3);
  }

  50% {
    transform: scale(1.02);
    box-shadow: 0 0 15px rgba(255, 204, 0, 0.5);
  }

  100% {
    transform: scale(1);
    box-shadow: 0 0 5px rgba(255, 204, 0, 0.3);
  }
}

.workshop__list-icon {
  flex-shrink: 0;
  color: var(--clr-primary);
  margin-top: 2px;
}

/* Button Link Icon Refined */
.btn--link-icon {
  display: inline-flex;
  align-items: center;
  gap: 1.25rem;
  color: var(--clr-white);
  font-weight: var(--fw-bold);
  font-size: var(--fs-base);
  transition: all var(--transition-base);
  padding: 0.5rem 0;
}

.btn--link-icon:hover {
  color: var(--clr-primary);
  transform: translateX(6px);
}

.btn__icon {
  width: 40px;
  height: 40px;
  background: var(--clr-primary);
  color: var(--clr-white);
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  box-shadow: 0 4px 15px rgba(27, 171, 154, 0.3);
  transition: all var(--transition-base);
}

/* Price styling */
.workshop__price {
  display: flex;
  align-items: baseline;
  gap: 1.25rem;
  margin-bottom: 2rem;
}

.workshop__price-original {
  font-size: var(--fs-md);
  color: rgba(255, 255, 255, 0.4);
  text-decoration: line-through;
  font-weight: var(--fw-medium);
}

.workshop__price-original.no_discount {
  text-decoration: none !important;
  color: var(--clr-primary);
  font-size: var(--fs-2xl);
  font-weight: var(--fw-bold);
  opacity: 1;
}

.workshop__price-discount {
  font-size: var(--fs-2xl);
  color: var(--clr-primary);
  font-weight: var(--fw-bold);
  letter-spacing: -0.01em;
}

.workshop__price-tag {
  font-size: var(--fs-xs);
  background: #ff4757;
  color: #fff;
  padding: 0.2rem 0.6rem;
  border-radius: 4px;
  font-weight: var(--fw-bold);
  text-transform: uppercase;
  margin-left: -0.5rem;
}

.btn--link-icon:hover .btn__icon {
  transform: rotate(-10deg) scale(1.1);
  background: var(--clr-white);
  color: var(--clr-primary);
}

/* Indicators Refined */
.workshop__indicators {
  position: absolute;
  right: var(--container-px);
  top: 50%;
  transform: translateY(-50%);
  z-index: 10;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.workshop__ind {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  background: transparent;
  color: rgba(255, 255, 255, 0.3);
  transition: all 0.4s ease;
  padding: 0.5rem;
}

.workshop__ind-num {
  font-size: var(--fs-md);
  font-weight: var(--fw-bold);
  width: 24px;
  text-align: right;
}

.workshop__ind-line {
  width: 0;
  height: 1px;
  background: var(--clr-primary);
  transition: all 0.4s cubic-bezier(0.19, 1, 0.22, 1);
  opacity: 0;
  margin-right: 0;
}

.workshop__ind.active {
  color: var(--clr-primary);
}

.workshop__ind.active .workshop__ind-line {
  width: 40px;
  margin-right: 1rem;
  opacity: 1;
}

@media (max-width: 991px) {
  .workshop__text {
    max-width: 100%;
    padding: 2.5rem;
    margin: 0 1rem;
    transform: none;
  }

  .workshop__list {
    grid-template-columns: 1fr;
    gap: 0.75rem;
  }

  .workshop__indicators {
    right: 20px;
  }
}

@media (max-width: 768px) {
  .workshop {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: 0 !important;
  }

  .workshop__track {
    height: 100%;
    min-height: 100vh;
  }

  .workshop__slide {
    padding: 80px 0 100px !important;
    display: flex !important;
    align-items: center !important;
    justify-content: center !important;
    height: 100% !important;
  }

  .workshop__slide:not(.active) {
    position: absolute !important;
    inset: 0 !important;
    opacity: 0 !important;
    visibility: hidden !important;
  }

  .workshop__text {
    max-width: 92% !important;
    padding: 2.25rem 1.5rem !important;
    margin: 0 auto !important;
    background: rgba(0, 0, 0, 0.7) !important;
    backdrop-filter: blur(16px) !important;
    -webkit-backdrop-filter: blur(16px) !important;
    border: 1px solid rgba(255, 255, 255, 0.1) !important;
  }

  .workshop__title {
    font-size: 1.75rem !important;
    margin-bottom: 1rem;
  }

  .workshop__description {
    font-size: 0.95rem;
    padding-left: 1rem;
    margin-bottom: 1.5rem;
    line-height: 1.6;
    color: rgba(255, 255, 255, 0.9);
  }

  .workshop__list {
    display: grid;
    grid-template-columns: 1fr;
    gap: 0.75rem;
    margin-bottom: 2rem;
  }

  .workshop__list li {
    font-size: 0.85rem;
    display: flex;
    align-items: center;
    gap: 0.6rem;
    color: rgba(255, 255, 255, 0.9);
  }

  .workshop__price {
    margin-bottom: 1.5rem;
    gap: 0.75rem;
  }

  .workshop__price-discount {
    font-size: 1.75rem;
  }

  .workshop__indicators {
    flex-direction: row !important;
    left: 50% !important;
    right: auto !important;
    bottom: 40px !important;
    top: auto !important;
    transform: translateX(-50%) !important;
    gap: 1rem !important;
    width: auto;
  }

  .workshop__ind {
    padding: 0.5rem !important;
  }

  .workshop__ind-num {
    font-size: 0.8rem !important;
  }

  .workshop__ind-line {
    display: none;
  }

  .workshop__ind.active {
    background: var(--clr-primary);
    border-radius: var(--radius-full);
    color: var(--clr-white);
    padding: 0.4rem 1rem !important;
  }
}


/* ============================================================
   BOOKS
   ============================================================ */
.books__grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: center;
}

.books__title {
  font-size: var(--fs-3xl);
  font-weight: var(--fw-extrabold);
  line-height: var(--lh-tight);
  color: var(--clr-text);
  margin-bottom: 1rem;
}

.books__desc {
  font-size: var(--fs-base);
  color: var(--clr-text-muted);
  line-height: var(--lh-base);
  margin-bottom: 1.75rem;
}

.books__thumbs {
  display: flex;
  gap: 1rem;
  margin-top: 2rem;
}

.books__thumb {
  position: relative;
  flex: 0 0 120px;
  transition: transform var(--transition-base);
}

.books__image {
  position: relative;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}

.books__coming-soon {
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  color: #fff;
  text-align: center;
  z-index: 5;
  pointer-events: none;
  animation: fadeInOut 0.5s ease;
}

.books__coming-soon.active {
  display: flex;
}

.books__coming-soon span {
  font-size: 2rem;
  font-weight: var(--fw-extrabold);
  text-transform: uppercase;
  letter-spacing: 4px;
  text-shadow: 0 4px 10px rgba(0, 0, 0, 0.5);
}

.books__coming-soon small {
  font-size: 1.2rem;
  margin-top: 12px;
  letter-spacing: 2px;
  opacity: 0.9;
}

@keyframes fadeInOut {
  from {
    opacity: 0;
    transform: scale(0.95);
  }

  to {
    opacity: 1;
    transform: scale(1);
  }
}

.books__thumb:hover {
  transform: translateY(-4px) scale(1.02);
}

.books__thumb img {
  width: 100%;
  height: 160px;
  object-fit: cover;
}

.books__thumb span {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  background: linear-gradient(0deg, rgba(0, 0, 0, 0.72) 0%, transparent 100%);
  color: var(--clr-white);
  font-size: var(--fs-xs);
  font-weight: var(--fw-semibold);
  padding: 0.5rem 0.5rem 0.4rem;
  line-height: 1.3;
}

.books__featured {
  display: flex;
  justify-content: center;
  align-items: center;
}

.books__featured img {
  width: 100%;
  max-width: 380px;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  transition: transform var(--transition-slow), box-shadow var(--transition-slow);
}

.books__featured img:hover {
  transform: translateY(-6px) rotate(1deg);
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.22);
}


/* ============================================================
   STATS
   ============================================================ */
.stats {
  background: var(--clr-bg-off);
}

.stats__title {
  font-size: var(--fs-3xl);
  font-weight: var(--fw-extrabold);
  text-align: center;
  line-height: var(--lh-tight);
  margin-bottom: 0.75rem;
  color: var(--clr-text);
}

.stats__subtitle {
  text-align: center;
  font-style: italic;
  color: var(--clr-text-muted);
  font-size: var(--fs-base);
  margin-bottom: 3.5rem;
}

.stats__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
  justify-items: center;
}

.stats__item {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.4rem;
  padding: 0 0 0 2rem;
  border-left: 3px solid var(--clr-primary);
}

.stats__number {
  font-size: var(--fs-4xl);
  font-weight: var(--fw-extrabold);
  color: var(--clr-text);
  line-height: 1;
  letter-spacing: -0.02em;
}

.stats__label {
  font-size: var(--fs-sm);
  color: var(--clr-text-muted);
  line-height: var(--lh-snug);
}


/* ============================================================
   BENEFITS
   ============================================================ */
.benefits__heading {
  font-size: var(--fs-2xl);
  font-weight: var(--fw-extrabold);
  color: var(--clr-text);
  margin-bottom: 2.5rem;
}

.benefits__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}

.benefits__item {
  padding: 2rem 1.75rem;
  background: var(--clr-bg-off);
  border-radius: var(--radius-md);
  border-top: 3px solid var(--clr-primary);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.benefits__item:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.benefits__icon {
  width: 44px;
  height: 44px;
  color: var(--clr-primary);
  margin-bottom: 1rem;
}

.benefits__icon svg {
  width: 100%;
  height: 100%;
}

.benefits__name {
  font-size: var(--fs-lg);
  font-weight: var(--fw-bold);
  color: var(--clr-text);
  margin-bottom: 0.6rem;
}

.benefits__desc {
  font-size: var(--fs-sm);
  color: var(--clr-text-muted);
  line-height: var(--lh-base);
}


/* ============================================================
   COMMUNITY
   ============================================================ */
.community {
  background: var(--clr-bg-off);
  padding: var(--section-py-sm) 0;
}

.community__label {
  font-size: var(--fs-sm);
  color: var(--clr-text-muted);
  margin-bottom: 1.25rem;
  font-weight: var(--fw-medium);
  text-align: center;
}

.community__grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
}

.community__card {
  position: relative;
  border-radius: var(--radius-lg);
  overflow: hidden;
  min-height: 180px;
  cursor: pointer;
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.community__card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-primary);
}

.community__bg {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center;
  transition: transform var(--transition-slow);
}

.community__card:hover .community__bg {
  transform: scale(1.04);
}

.community__card--light .community__bg {
  filter: brightness(0.88);
}

.community__card--dark .community__bg {
  filter: brightness(0.72);
}

.community__card-inner {
  position: relative;
  z-index: 2;
  padding: 1.75rem 1.75rem 1.5rem;
  height: 100%;
  display: flex;
  flex-direction: column;
}

.community__card-title {
  font-size: var(--fs-xl);
  font-weight: var(--fw-extrabold);
  color: var(--clr-white);
  margin-bottom: 0.75rem;
}

.community__card-desc {
  font-size: var(--fs-sm);
  color: rgba(255, 255, 255, 0.88);
  line-height: var(--lh-base);
  flex: 1;
  margin-bottom: 1rem;
  max-width: 320px;
}

.community__arrow {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  border: 2px solid rgba(255, 255, 255, 0.75);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--clr-white);
  font-size: 1rem;
  align-self: flex-end;
  transition: all var(--transition-fast);
}

.community__arrow:hover {
  background: rgba(255, 255, 255, 0.25);
  border-color: var(--clr-white);
}


/* ============================================================
   EXPERT
   ============================================================ */
.expert {
  background: var(--clr-bg);
  padding: var(--section-py) 0;
}

.expert__card {
  position: relative;
  background: linear-gradient(135deg, #F0FEFE 0%, #E0FBFA 100%);
  border-radius: 40px;
  overflow: hidden;
  box-shadow: 0 20px 60px rgba(27, 171, 154, 0.06);
  border: 1px solid rgba(27, 171, 154, 0.1);
}

.expert__card::after {
  content: '';
  position: absolute;
  bottom: -50px;
  left: -20px;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(22, 211, 193, 0.1) 0%, transparent 70%);
  z-index: 1;
  pointer-events: none;
}

.expert__grid {
  position: relative;
  z-index: 2;
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  align-items: center;
  gap: 2rem;
}

.expert__info {
  padding: 4rem 1rem 4rem 5rem;
  position: relative;
}

.expert__title {
  font-size: var(--fs-4xl);
  font-weight: var(--fw-bold);
  color: #000;
  line-height: 1.2;
  margin-bottom: 2rem;
}

.expert__desc {
  font-size: var(--fs-base);
  color: #444;
  line-height: 1.7;
  margin-bottom: 2.5rem;
  max-width: 480px;
}

.expert__phone {
  display: flex;
  justify-content: flex-end;
  padding: 3rem 5rem 3rem 0;
}

.phone-frame {
  width: 280px;
  background: #000;
  padding: 10px;
  border-radius: 40px;
  box-shadow: 0 40px 80px rgba(0, 0, 0, 0.25);
  position: relative;
  border: 4px solid #1a1a1a;
  overflow: hidden;
  animation: phoneFloat 6s ease-in-out infinite;
  aspect-ratio: 9/19;
}

.phone-frame::before {
  content: '';
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 100px;
  height: 25px;
  background: #000;
  border-bottom-left-radius: 12px;
  border-bottom-right-radius: 12px;
  z-index: 10;
}

.phone-img {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0;
  visibility: hidden;
  transition: opacity 1s ease, transform 1s ease;
  transform: scale(1.05);
}

.phone-img.active {
  opacity: 1;
  visibility: visible;
  transform: scale(1);
  z-index: 2;
}

@keyframes phoneFloat {

  0%,
  100% {
    transform: translateY(0) rotate(1deg);
  }

  50% {
    transform: translateY(-15px) rotate(-1deg);
  }
}


/* ============================================================
   FOOTER
   ============================================================ */
.footer {
  position: relative;
  overflow: hidden;
}

.footer__bg {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center;
}

.footer__bg::after {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--gradient-footer);
  opacity: 0.92;
}

.footer__inner {
  position: relative;
  z-index: 2;
  text-align: center;
  padding: 3.5rem 0 2.5rem;
}

.footer__heading {
  font-size: var(--fs-xl);
  font-weight: var(--fw-extrabold);
  color: var(--clr-white);
  letter-spacing: 0.1em;
  margin-bottom: 1.75rem;
}

.footer__contacts {
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
  align-items: center;
  margin-bottom: 2rem;
}

.footer__contacts p {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: var(--fs-sm);
  color: rgba(255, 255, 255, 0.88);
}

.footer__contacts svg {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
  opacity: 0.75;
}

.footer__socials {
  display: flex;
  justify-content: center;
  gap: 0.75rem;
  margin-bottom: 2rem;
}

.footer__social {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  border: 1.5px solid rgba(255, 255, 255, 0.45);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--clr-white);
  transition: all var(--transition-fast);
}

.footer__social svg {
  width: 18px;
  height: 18px;
}

.footer__social:hover {
  background: rgba(255, 255, 255, 0.2);
  border-color: var(--clr-white);
  transform: translateY(-2px);
}

.footer__divider {
  width: 60px;
  height: 1px;
  background: rgba(255, 255, 255, 0.25);
  margin: 0 auto 1.5rem;
}

.footer__copy {
  font-size: var(--fs-xs);
  color: rgba(255, 255, 255, 0.6);
  line-height: var(--lh-base);
}

.footer__copy small {
  font-size: 0.7rem;
  color: rgba(255, 255, 255, 0.4);
}


/* ============================================================
   RESPONSIVE DESIGN SYSTEM
   ============================================================ */

/* TABLET (Lớn hơn Mobile - Nhỏ hơn Desktop) */
@media (max-width: 1024px) {
  :root {
    --container-px: 32px;
    --section-py: 80px;
  }

  .expert__grid {
    gap: 3rem;
  }
}

/* MOBILE CHUNG (Dưới 768px) */
@media (max-width: 768px) {
  :root {
    --section-py: 60px;
    --container-px: 20px;
  }

  /* --- Navigation --- */
  .header {
    background: #FFFFFF;
    backdrop-filter: none;
    -webkit-backdrop-filter: none;
  }

  .nav__menu {
    position: fixed;
    top: 0;
    right: 0;
    width: 300px;
    height: 100vh;
    background: #FFFFFF;
    backdrop-filter: none;
    -webkit-backdrop-filter: none;
    flex-direction: column;
    padding: 7rem 2rem 3rem;
    gap: 0.5rem;
    z-index: 2000;
    box-shadow: -15px 0 50px rgba(0, 0, 0, 0.1);
    transform: translateX(100%);
    visibility: hidden;
    transition: all 0.6s cubic-bezier(0.22, 1, 0.36, 1);
  }

  .nav__menu.open {
    transform: translateX(0);
    visibility: visible;
  }

  .nav__menu li {
    width: 100%;
    opacity: 0;
    transform: translateX(40px);
    transition: all 0.5s ease;
  }

  .nav__menu.open li {
    opacity: 1;
    transform: translateX(0);
  }

  /* Link delays for cascade effect */
  .nav__menu.open li:nth-child(1) {
    transition-delay: 0.1s;
  }

  .nav__menu.open li:nth-child(2) {
    transition-delay: 0.15s;
  }

  .nav__menu.open li:nth-child(3) {
    transition-delay: 0.2s;
  }

  .nav__menu.open li:nth-child(4) {
    transition-delay: 0.25s;
  }

  .nav__link {
    width: 100%;
    padding: 1rem 1.5rem;
    border-radius: var(--radius-md);
    font-size: 1.1rem;
    justify-content: flex-start !important;
  }

  .nav__link--active {
    background: var(--clr-primary);
    box-shadow: 0 4px 15px rgba(27, 171, 154, 0.25);
  }

  .nav__btn-menu {
    display: flex;
  }

  .nav__separator {
    display: none;
  }

  /* --- Sections --- */
  .hero {
    padding-top: calc(var(--nav-height) + 60px);
    padding-bottom: 60px;
  }

  .books__grid,
  .expert__grid,
  .stats__grid,
  .benefits__grid,
  .community__grid {
    grid-template-columns: 1fr;
    gap: 2.5rem;
  }

  /* Books */
  .books__image {
    order: -1;
    max-width: 320px;
    margin: 0 auto;
  }

  .books__info {
    text-align: center;
  }

  .books__thumbs {
    justify-content: center;
  }

  /* Stats */
  .stats__grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 2rem 1rem;
  }

  .stats__item {
    align-items: center;
    text-align: center;
    padding: 0;
    border-left: none;
    border-bottom: 2px solid var(--clr-primary-bg);
    padding-bottom: 1rem;
  }

  .stats__item:last-child {
    grid-column: span 2;
    border-bottom: none;
  }

  .stats__number {
    font-size: 2.5rem;
  }

  /* Benefits */
  .benefits__item {
    text-align: center;
    padding: 2.5rem 1.5rem;
  }

  .benefits__icon {
    margin: 0 auto 1.5rem;
  }

  /* Expert - Re-integrated Phone for Mobile */
  .expert__info {
    padding: 3rem 1.5rem;
    text-align: center;
  }

  .expert__info .btn {
    width: 100%;
    justify-content: center;
  }

  .expert__desc {
    margin: 0 auto 2rem;
  }

  .expert__phone {
    display: flex;
    justify-content: center;
    padding: 0 0 3rem;
  }

  .phone-frame {
    width: 220px;
    padding: 8px;
    border-radius: 32px;
  }

  .phone-frame::before {
    width: 70px;
    height: 18px;
  }
}

/* SMALL MOBILE (Dưới 480px) */
@media (max-width: 480px) {
  .hero__title {
    font-size: 2.25rem;
  }

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

  .stats__item:last-child {
    grid-column: span 1;
  }

  .workshop__text {
    padding: 1.5rem 1rem !important;
  }

  .workshop__title {
    font-size: 1.5rem !important;
  }

  .workshop__price-discount {
    font-size: 1.5rem;
  }

  .footer__contacts p {
    font-size: 0.8rem;
  }
}

/* ============================================================
   FEEDBACK SECTION
   ============================================================ */
.feedback {
  background: var(--clr-bg-off);
}

.feedback__header {
  text-align: center;
  margin-bottom: 3rem;
}

.feedback__title {
  font-size: var(--fs-h3);
  font-weight: var(--fw-bold);
  color: #111;
  margin-bottom: 0.75rem;
}

.feedback__subtitle {
  color: var(--clr-text-muted);
  max-width: 600px;
  margin: 0 auto;
}

.feedback__grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 2rem;
}

.feedback__card {
  background: var(--clr-white);
  padding: 2.5rem;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-base);
  display: flex;
  flex-direction: column;
  position: relative;
  overflow: hidden;
}

.feedback__card::before {
  content: '"';
  position: absolute;
  top: 1rem;
  right: 1.5rem;
  font-size: 4rem;
  font-family: serif;
  color: var(--clr-primary-bg);
  line-height: 1;
}

.feedback__card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-md);
  border-color: var(--clr-primary-light);
}

.feedback__author {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  margin-bottom: 1.5rem;
}

.feedback__avatar {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  object-fit: cover;
  background: var(--clr-primary-bg);
  border: 2px solid var(--clr-white);
  box-shadow: 0 0 0 1.5px var(--clr-primary-light);
}

.feedback__info-text {
  display: flex;
  flex-direction: column;
}

.feedback__name {
  font-weight: var(--fw-bold);
  color: var(--clr-text);
  font-size: 1rem;
  margin-bottom: 2px;
}

.feedback__stars {
  color: #FFB800;
  display: flex;
  gap: 2px;
  font-size: 0.85rem;
}

.feedback__comment {
  font-size: 0.95rem;
  color: var(--clr-text-muted);
  line-height: 1.7;
  font-style: italic;
  position: relative;
  z-index: 1;
}

.feedback__loading {
  grid-column: 1 / -1;
  text-align: center;
  padding: 4rem;
  color: var(--clr-primary);
  font-weight: var(--fw-medium);
  font-style: italic;
}

.feedback__error {
  grid-column: 1 / -1;
  text-align: center;
  padding: 2rem;
  color: #e74c3c;
}

@media (max-width: 768px) {
  .feedback__grid {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }
}