/* ==========================================================================
   CUSTOM FONTS - ALUMNI SANS
   ========================================================================== */
@font-face {
  font-family: 'Alumni Sans';
  src: url('../fonts/Alumni_Sans/AlumniSans-VariableFont_wght.ttf') format('truetype-variations'),
       url('../../Alumni_Sans/AlumniSans-VariableFont_wght.ttf') format('truetype-variations'),
       url('../fonts/Alumni_Sans/static/AlumniSans-Regular.ttf') format('truetype');
  font-weight: 100 900;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: 'Alumni Sans';
  src: url('../fonts/Alumni_Sans/AlumniSans-Italic-VariableFont_wght.ttf') format('truetype-variations'),
       url('../../Alumni_Sans/AlumniSans-Italic-VariableFont_wght.ttf') format('truetype-variations'),
       url('../fonts/Alumni_Sans/static/AlumniSans-Italic.ttf') format('truetype');
  font-weight: 100 900;
  font-style: italic;
  font-display: swap;
}

@font-face {
  font-family: 'Alumni Sans';
  src: url('../fonts/Alumni_Sans/static/AlumniSans-Bold.ttf') format('truetype'),
       url('../../Alumni_Sans/static/AlumniSans-Bold.ttf') format('truetype');
  font-weight: 700;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: 'Alumni Sans';
  src: url('../fonts/Alumni_Sans/static/AlumniSans-SemiBold.ttf') format('truetype'),
       url('../../Alumni_Sans/static/AlumniSans-SemiBold.ttf') format('truetype');
  font-weight: 600;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: 'Alumni Sans';
  src: url('../fonts/Alumni_Sans/static/AlumniSans-Medium.ttf') format('truetype'),
       url('../../Alumni_Sans/static/AlumniSans-Medium.ttf') format('truetype');
  font-weight: 500;
  font-style: normal;
  font-display: swap;
}

/* ==========================================================================
   LIVING HERITAGE - BỘ SÁCH LONGEVITY 2026 LANDING PAGE
   Design System & Styling
   ========================================================================== */

:root {
  /* Palette */
  --bg-dark: #0b1411;
  --bg-card: rgba(18, 32, 27, 0.75);
  --bg-card-hover: rgba(24, 42, 35, 0.9);
  --bg-surface: #101c18;
  --bg-surface-light: #162621;

  --color-gold: #d4af37;
  --color-gold-light: #f3e2a9;
  --color-gold-dark: #b8860b;
  --color-gold-gradient: linear-gradient(135deg, #f5e4b3 0%, #d4af37 50%, #9e7514 100%);
  --color-gold-border: rgba(212, 175, 55, 0.28);
  --color-gold-glow: rgba(212, 175, 55, 0.35);

  --color-sand: #ca9f80;
  --color-text-main: #f0f4f2;
  --color-text-muted: #a6b8b0;
  --color-text-dim: #71847c;

  /* Typography */
  --font-display: 'Alumni Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-body: 'Alumni Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

  /* Transitions & Shadows */
  --shadow-card: 0 16px 40px rgba(0, 0, 0, 0.4);
  --shadow-gold: 0 8px 24px rgba(212, 175, 55, 0.25);
  --shadow-book: -10px 18px 30px rgba(0, 0, 0, 0.65), 0 0 20px rgba(212, 175, 55, 0.15);
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

/* Base Reset */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 19px;
  overflow-x: hidden;
  max-width: 100vw;
  width: 100%;
}

body {
  font-family: var(--font-body);
  background-color: var(--bg-dark);
  color: var(--color-text-main);
  line-height: 1.7;
  overflow-x: hidden;
  max-width: 100vw;
  width: 100%;
  background-image: 
    radial-gradient(circle at 15% 20%, rgba(212, 175, 55, 0.05) 0%, transparent 40%),
    radial-gradient(circle at 85% 70%, rgba(202, 159, 128, 0.04) 0%, transparent 45%),
    radial-gradient(circle at 50% 90%, rgba(212, 175, 55, 0.03) 0%, transparent 50%);
  background-attachment: fixed;
}

a {
  color: inherit;
  text-decoration: none;
  transition: var(--transition);
}

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

.container {
  width: 100%;
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Typography Helpers */
h1, h2, h3, h4, .font-display {
  font-family: var(--font-display);
  letter-spacing: 0.04em;
  font-weight: 700;
  text-transform: uppercase;
  text-wrap: balance;
}

.text-gold {
  color: var(--color-gold);
}

.text-gradient-gold {
  background: var(--color-gold-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  display: inline-block;
}

.text-muted {
  color: var(--color-text-muted);
}

.text-sand {
  color: var(--color-sand);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 14px 28px;
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: 0.03em;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: var(--transition);
  border: 1px solid transparent;
  text-transform: uppercase;
}

.btn-gold {
  background: var(--color-gold-gradient);
  color: #0b1f1a;
  box-shadow: var(--shadow-gold);
  border-color: #f3e2a9;
}

.btn-gold:hover {
  transform: translateY(-3px);
  box-shadow: 0 12px 28px rgba(212, 175, 55, 0.45);
  filter: brightness(1.08);
  color: #050f0c;
}

.btn-gold:active {
  transform: translateY(0);
}

.btn-outline-gold {
  background: rgba(212, 175, 55, 0.06);
  border-color: var(--color-gold);
  color: var(--color-gold-light);
  backdrop-filter: blur(8px);
}

.btn-outline-gold:hover {
  background: var(--color-gold);
  color: #0b1f1a;
  transform: translateY(-3px);
  box-shadow: var(--shadow-gold);
}

.btn-outline-white {
  background: rgba(255, 255, 255, 0.05);
  border-color: rgba(255, 255, 255, 0.2);
  color: #ffffff;
}

.btn-outline-white:hover {
  background: #ffffff;
  color: #0b1f1a;
  transform: translateY(-2px);
}

/* ==========================================================================
   HEADER / NAVBAR
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(11, 20, 17, 0.92);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--color-gold-border);
  padding: 16px 0;
  transition: var(--transition);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

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

.site-logo img {
  height: 44px;
  width: auto;
  object-fit: contain;
}

.site-logo .logo-divider {
  width: 1px;
  height: 28px;
  background: var(--color-gold-border);
}

.site-logo .logo-tagline {
  font-size: 0.78rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--color-gold);
  font-family: var(--font-display);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
  list-style: none;
}

.nav-links a {
  font-size: 1.2rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  position: relative;
  padding: 6px 0;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--color-gold-light);
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-gold);
  transition: var(--transition);
}

.nav-links a:hover::after,
.nav-links a.active::after {
  width: 100%;
}

.nav-cta {
  display: flex;
  align-items: center;
  gap: 12px;
}

.mobile-toggle {
  display: none;
  background: none;
  border: 1px solid var(--color-gold-border);
  color: var(--color-gold);
  font-size: 1.25rem;
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  cursor: pointer;
}

/* ==========================================================================
   HERO SECTION
   ========================================================================== */
.hero-section {
  position: relative;
  padding: 80px 0 100px;
  overflow: hidden;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  border-radius: 50px;
  background: rgba(212, 175, 55, 0.1);
  border: 1px solid var(--color-gold-border);
  color: var(--color-gold);
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  margin-bottom: 24px;
}

.hero-title {
  font-size: clamp(2.4rem, 4.8vw, 4rem);
  font-weight: 700;
  line-height: 1.15;
  margin-bottom: 24px;
  text-wrap: balance;
}

.hero-subtitle {
  font-size: clamp(1.05rem, 1.8vw, 1.25rem);
  color: var(--color-text-muted);
  max-width: 760px;
  line-height: 1.8;
  margin-bottom: 36px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  margin-bottom: 60px;
}

/* Hero 3-Book Showcase */
.hero-showcase {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
  margin-top: 20px;
}

.hero-book-card {
  background: var(--bg-card);
  border: 1px solid var(--color-gold-border);
  border-radius: var(--radius-md);
  padding: 24px;
  text-align: center;
  transition: var(--transition);
  position: relative;
  backdrop-filter: blur(10px);
}

.hero-book-card:hover {
  transform: translateY(-8px);
  border-color: var(--color-gold);
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.5), 0 0 25px rgba(212, 175, 55, 0.2);
}

.hero-book-img-wrap {
  position: relative;
  padding: 10px;
  margin-bottom: 20px;
}

.hero-book-img-wrap img {
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-book);
  margin: 0 auto;
  max-height: 380px;
  object-fit: cover;
  transition: var(--transition);
}

.hero-book-card:hover .hero-book-img-wrap img {
  transform: scale(1.03) rotate(-1deg);
}

.hero-book-card .vol-tag {
  display: inline-block;
  font-size: 0.95rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-sand);
  font-weight: 600;
  margin-bottom: 8px;
}

.hero-book-card h3 {
  font-size: 1.25rem;
  margin-bottom: 8px;
  color: #fff;
  line-height: 1.4;
}

.hero-book-card .author {
  font-size: 0.88rem;
  color: var(--color-text-muted);
  font-style: italic;
  margin-bottom: 16px;
}

/* ==========================================================================
   PHILOSOPHY / INTRO
   ========================================================================== */
.quote-section {
  padding: 70px 0;
  border-top: 1px solid rgba(212, 175, 55, 0.15);
  border-bottom: 1px solid rgba(212, 175, 55, 0.15);
  background: rgba(16, 28, 24, 0.5);
  text-align: center;
}

.quote-box {
  max-width: 860px;
  margin: 0 auto;
}

.quote-icon {
  font-size: 2.5rem;
  color: var(--color-gold);
  opacity: 0.7;
  margin-bottom: 16px;
}

.quote-text {
  font-family: var(--font-display);
  font-size: clamp(1.2rem, 2.2vw, 1.6rem);
  font-style: italic;
  line-height: 1.7;
  color: var(--color-gold-light);
  margin-bottom: 20px;
}

.quote-author {
  font-size: 0.95rem;
  color: var(--color-sand);
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

/* ==========================================================================
   BOOK DETAIL SHOWCASE SECTION
   ========================================================================== */
.books-section {
  padding: 100px 0;
}

.section-head {
  text-align: center;
  max-width: 780px;
  margin: 0 auto 60px;
}

.section-badge {
  display: inline-block;
  font-size: 1rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--color-gold);
  font-weight: 600;
  margin-bottom: 12px;
}

.section-title {
  font-size: clamp(1.8rem, 3.2vw, 2.8rem);
  line-height: 1.3;
  margin-bottom: 16px;
}

.section-desc {
  font-size: 1.05rem;
  color: var(--color-text-muted);
}

.book-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
  background: var(--bg-card);
  border: 1px solid var(--color-gold-border);
  border-radius: var(--radius-lg);
  padding: 48px;
  margin-bottom: 50px;
  backdrop-filter: blur(8px);
  transition: var(--transition);
}

.book-row:hover {
  border-color: rgba(212, 175, 55, 0.4);
  box-shadow: var(--shadow-card);
}

.book-row.reversed {
  grid-template-columns: 1fr 1fr;
}

.book-row.reversed .book-media {
  order: 2;
}

.book-row.reversed .book-info {
  order: 1;
}

.book-media {
  display: flex;
  justify-content: center;
  position: relative;
}

.book-media img {
  max-width: 440px;
  width: 100%;
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-book);
  transition: var(--transition);
}

.book-row:hover .book-media img {
  transform: translateY(-6px);
}

.book-info .book-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.8rem;
  color: var(--color-gold);
  background: rgba(212, 175, 55, 0.1);
  border: 1px solid var(--color-gold-border);
  padding: 4px 12px;
  border-radius: 4px;
  margin-bottom: 16px;
  font-weight: 600;
  letter-spacing: 0.05em;
}

.book-info h3 {
  font-size: clamp(1.5rem, 2.4vw, 2.1rem);
  line-height: 1.3;
  margin-bottom: 10px;
}

.book-info .author-line {
  font-size: 1.05rem;
  color: var(--color-sand);
  font-style: italic;
  margin-bottom: 20px;
}

.book-info p {
  color: var(--color-text-muted);
  line-height: 1.8;
  margin-bottom: 20px;
}

.book-highlights {
  list-style: none;
  margin-bottom: 28px;
}

.book-highlights li {
  position: relative;
  padding-left: 24px;
  margin-bottom: 10px;
  color: #d1ded8;
  font-size: 0.95rem;
}

.book-highlights li::before {
  content: '✦';
  position: absolute;
  left: 0;
  color: var(--color-gold);
  font-size: 0.85rem;
}

.book-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}

/* ==========================================================================
   AUTHORS SECTION
   ========================================================================== */
.authors-section {
  padding: 90px 0;
  background: rgba(16, 28, 24, 0.6);
  border-top: 1px solid rgba(212, 175, 55, 0.15);
  border-bottom: 1px solid rgba(212, 175, 55, 0.15);
}

.authors-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 28px;
}

.author-card {
  background: var(--bg-card);
  border: 1px solid var(--color-gold-border);
  border-radius: var(--radius-md);
  padding: 24px;
  text-align: center;
  transition: var(--transition);
}

.author-card:hover {
  transform: translateY(-6px);
  border-color: var(--color-gold);
  box-shadow: var(--shadow-card);
}

.author-avatar {
  width: 154px;
  height: 154px;
  border-radius: 50%;
  overflow: hidden;
  margin: 0 auto 18px;
  border: 2px solid var(--color-gold);
  box-shadow: 0 6px 18px rgba(0, 0, 0, 0.4);
  background-color: #12201b;
  position: relative;
}

.author-avatar img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center top;
  transition: var(--transition);
}

/* Custom alignment so no author heads get cut off */
.author-avatar.pos-top img,
.author-avatar-top img {
  object-position: center top;
}

.author-avatar.pos-niels img,
.author-avatar-niels img {
  object-position: center 8%;
}

.author-avatar.pos-huong img,
.author-avatar-huong img {
  object-position: center 10%;
}

.author-avatar.pos-tu img,
.author-avatar-tu img {
  object-position: 72% center;
}

.author-card h4 {
  font-size: 1.15rem;
  margin-bottom: 6px;
  color: #fff;
}

.author-card .author-title {
  font-size: 0.85rem;
  color: var(--color-gold);
  margin-bottom: 12px;
  font-weight: 500;
}

.author-card p {
  font-size: 0.88rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}

/* ==========================================================================
   CTA BANNER SECTION
   ========================================================================== */
.cta-section {
  padding: 90px 0;
}

.cta-box {
  background: linear-gradient(135deg, rgba(212, 175, 55, 0.15) 0%, rgba(18, 32, 27, 0.95) 100%);
  border: 1px solid var(--color-gold);
  border-radius: var(--radius-lg);
  padding: 60px 40px;
  text-align: center;
  position: relative;
  overflow: hidden;
  box-shadow: 0 20px 50px rgba(0, 0, 0, 0.6), 0 0 30px rgba(212, 175, 55, 0.2);
}

.cta-box h2 {
  font-size: clamp(2rem, 3.5vw, 2.8rem);
  margin-bottom: 16px;
}

.cta-box p {
  font-size: 1.1rem;
  color: var(--color-text-muted);
  max-width: 680px;
  margin: 0 auto 32px;
}

.cta-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 16px;
  margin-bottom: 24px;
}

.cta-hotline {
  font-size: 0.95rem;
  color: var(--color-sand);
}

.cta-hotline strong {
  color: var(--color-gold-light);
}

/* ==========================================================================
   FOOTER
   ========================================================================== */
.site-footer {
  background: #070d0b;
  border-top: 1px solid var(--color-gold-border);
  padding: 50px 0 30px;
  color: var(--color-text-dim);
  font-size: 0.9rem;
}

.footer-content {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 24px;
  padding-bottom: 30px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 16px;
}

.footer-brand img {
  height: 38px;
}

.footer-nav {
  display: flex;
  gap: 24px;
  list-style: none;
}

.footer-nav a:hover {
  color: var(--color-gold);
}

.footer-bottom {
  padding-top: 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
  font-size: 0.85rem;
}

/* ==========================================================================
   DETAIL PAGE SPECIFIC STYLES
   ========================================================================== */
.detail-hero {
  padding: 60px 0 40px;
  border-bottom: 1px solid rgba(212, 175, 55, 0.15);
  background: rgba(16, 28, 24, 0.4);
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 10px;
  font-size: 0.88rem;
  color: var(--color-text-dim);
  margin-bottom: 24px;
  word-break: break-word;
}

.breadcrumb a {
  color: var(--color-gold);
}

.breadcrumb a:hover {
  text-decoration: underline;
}

.detail-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 320px;
  gap: 48px;
  padding: 60px 0 100px;
  width: 100%;
  max-width: 100%;
}

.detail-article {
  background: var(--bg-card);
  border: 1px solid var(--color-gold-border);
  border-radius: var(--radius-lg);
  padding: 44px;
  width: 100%;
  max-width: 100%;
  box-sizing: border-box;
  overflow-wrap: break-word;
  word-wrap: break-word;
  word-break: break-word;
}

.detail-article img {
  max-width: 100%;
  height: auto;
}

.detail-article h1 {
  font-size: clamp(1.8rem, 3vw, 2.4rem);
  line-height: 1.3;
  margin-bottom: 12px;
  color: #ffffff;
}

.detail-article h2 {
  font-size: 1.5rem;
  color: var(--color-gold-light);
  margin: 36px 0 16px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--color-gold-border);
}

.detail-article h3 {
  font-size: 1.25rem;
  color: var(--color-gold);
  margin: 28px 0 12px;
}

.detail-article p {
  color: #d1ded8;
  font-size: 1.02rem;
  line-height: 1.85;
  margin-bottom: 20px;
  text-align: justify;
}

.detail-article .author-header {
  font-size: 1.1rem;
  color: var(--color-sand);
  font-style: italic;
  margin-bottom: 24px;
}

.detail-article .book-cover-center,
.detail-article .author-photo-center {
  width: 100%;
  max-width: 100%;
  text-align: center;
  margin: 28px auto 20px;
  overflow: hidden;
  box-sizing: border-box;
}

.detail-article .book-cover-center img {
  width: 100%;
  max-width: min(440px, 100%);
  height: auto;
  margin: 0 auto;
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-book);
  display: block;
}

.detail-article .author-photo-center img {
  width: 100%;
  max-width: min(480px, 100%);
  height: auto;
  margin: 0 auto;
  border-radius: var(--radius-sm);
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.5);
  display: block;
}

/* Sidebar */
.detail-sidebar {
  position: sticky;
  top: 90px;
  height: fit-content;
}

.sidebar-card {
  background: var(--bg-card);
  border: 1px solid var(--color-gold-border);
  border-radius: var(--radius-md);
  padding: 28px;
  margin-bottom: 28px;
  text-align: center;
}

.sidebar-card h4 {
  font-size: 1.15rem;
  margin-bottom: 16px;
  color: #fff;
}

.sidebar-other-books {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.sidebar-book-item {
  display: flex;
  align-items: center;
  gap: 14px;
  text-align: left;
  padding: 10px;
  border-radius: var(--radius-sm);
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid transparent;
  transition: var(--transition);
}

.sidebar-book-item:hover {
  background: rgba(212, 175, 55, 0.08);
  border-color: var(--color-gold-border);
  transform: translateX(4px);
}

.sidebar-book-item img {
  width: 56px;
  height: auto;
  border-radius: 3px;
}

.sidebar-book-item .book-meta h5 {
  font-size: 0.9rem;
  color: #fff;
  line-height: 1.3;
  margin-bottom: 4px;
}

.sidebar-book-item .book-meta span {
  font-size: 0.75rem;
  color: var(--color-sand);
}

/* ==========================================================================
   RESPONSIVE DESIGN
   ========================================================================== */
@media (max-width: 1024px) {
  .hero-showcase {
    grid-template-columns: 1fr;
    max-width: 500px;
    margin: 30px auto 0;
  }

  .book-row,
  .book-row.reversed {
    grid-template-columns: 1fr;
    padding: 32px 24px;
    gap: 36px;
  }

  .book-row.reversed .book-media {
    order: 0;
  }

  .detail-layout {
    display: flex;
    flex-direction: column;
    gap: 36px;
    padding: 30px 0 60px;
    width: 100%;
    max-width: 100%;
  }

  .detail-sidebar {
    position: static;
    width: 100%;
    max-width: 100%;
  }
}

@media (max-width: 768px) {
  html {
    font-size: 17px;
  }

  .container {
    padding: 0 16px;
    max-width: 100vw;
    box-sizing: border-box;
  }

  .site-header {
    width: 100%;
    max-width: 100vw;
    box-sizing: border-box;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    max-width: 100vw;
    box-sizing: border-box;
    background: #0b1411;
    border-bottom: 1px solid var(--color-gold-border);
    flex-direction: column;
    padding: 20px 16px;
    gap: 16px;
  }

  .nav-links.active {
    display: flex;
  }

  .mobile-toggle {
    display: block;
  }

  /* Refined, balanced buttons on mobile - NOT oversized & hide icon to save space */
  .nav-cta .btn {
    padding: 7px 12px;
    font-size: 0.92rem;
    width: auto;
    gap: 0;
    white-space: nowrap;
  }

  /* Bỏ icon trong nút Đặt sách trên view mobile để không chiếm chỗ */
  .nav-cta .btn i,
  .btn i.fa-book,
  .btn i.fa-book-open,
  .btn i.fa-cart-shopping {
    display: none !important;
  }

  /* Khóa cứng kích thước ảnh bài viết trên mobile chống tràn ngang */
  .detail-article {
    overflow: hidden;
    max-width: 100%;
    box-sizing: border-box;
  }

  .detail-article .book-cover-center img,
  .detail-article .author-photo-center img {
    max-width: 100% !important;
    width: 100% !important;
    height: auto !important;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.4) !important;
  }

  .hero-section {
    padding: 48px 0 60px;
  }

  .hero-actions {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
    width: 100%;
    margin-bottom: 36px;
  }

  .hero-actions .btn {
    width: 100%;
    max-width: 270px;
    padding: 11px 22px;
    font-size: 1rem;
    margin: 0 auto;
  }

  .hero-book-card {
    padding: 20px 16px;
  }

  .hero-book-card .btn {
    width: auto;
    padding: 8px 16px;
    font-size: 0.88rem;
  }

  .book-actions {
    display: flex;
    flex-direction: column;
    gap: 10px;
    width: 100%;
  }

  .book-actions .btn {
    width: 100%;
    max-width: 260px;
    padding: 10px 20px;
    font-size: 0.95rem;
  }

  .cta-section {
    padding: 60px 0;
  }

  .cta-box {
    padding: 36px 16px;
  }

  .cta-actions {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
    width: 100%;
  }

  .cta-actions .btn {
    width: 100%;
    max-width: 280px;
    padding: 12px 24px;
    font-size: 1rem;
    margin: 0 auto;
  }

  .detail-article {
    padding: 22px 14px;
    border-radius: var(--radius-md);
  }

  .detail-article h1 {
    font-size: 1.6rem;
  }

  .detail-article h2 {
    font-size: 1.3rem;
    margin: 28px 0 14px;
  }

  .detail-article p {
    font-size: 0.98rem;
    line-height: 1.75;
    text-align: left;
  }

  .footer-content {
    flex-direction: column;
    text-align: center;
  }

  .footer-nav {
    flex-direction: column;
    gap: 12px;
  }

  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }
}