/* 
 * Hành Trình Volvo Website Styles
 * Inspired by VNPEDIA layout with Volvo brand colors
 */

/* ============================================
   CSS VARIABLES - COLOR PALETTE & TYPOGRAPHY
   ============================================ */
:root {
  /* Colors from Volvo book cover */
  --color-bg-main: #0E3953;      /* Deep Volvo blue - hero, footer, accent */
  --color-bg-soft: #0F4563;      /* Mid blue for blocks */
  --color-accent: #F5F6F7;       /* Very light gray/cold for section backgrounds */
  --color-text-main: #111111;    /* Deep black */
  --color-text-light: #FFFFFF;   /* White */
  --color-link: #0E3953;         /* Link color */
  --color-link-hover: #0a2a3d;   /* Darker blue for hover */
  
  /* Navigation blocks colors */
  --color-nav-block-1: #111111;
  --color-nav-block-2: #1E1E1E;
  --color-nav-block-3: #303030;
  
  /* Typography */
  --font-heading: 'Merriweather', serif;
  --font-body: 'Inter', sans-serif;
  
  /* Layout */
  --max-width-content: 1160px;
  --max-width-text: 900px;
  --header-height: 80px;
  
  /* Spacing */
  --spacing-xs: 8px;
  --spacing-sm: 16px;
  --spacing-md: 32px;
  --spacing-lg: 64px;
  --spacing-xl: 96px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  font-weight: 300;
  font-size: 16px;
  line-height: 1.7;
  color: var(--color-text-main);
  background-color: var(--color-text-light);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ============================================
   TYPOGRAPHY
   ============================================ */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: var(--spacing-md);
}

h1 {
  font-size: clamp(2.5rem, 5vw, 4rem);
  letter-spacing: -0.02em;
}

h2 {
  font-size: clamp(2rem, 4vw, 3rem);
  letter-spacing: -0.01em;
}

h3 {
  font-size: clamp(1.5rem, 3vw, 2rem);
}

h4 {
  font-size: clamp(1.25rem, 2.5vw, 1.5rem);
}

p {
  margin-bottom: var(--spacing-sm);
  font-weight: 400;
}

a {
  color: var(--color-link);
  text-decoration: none;
  transition: all 0.3s ease;
}

a:hover {
  color: var(--color-link-hover);
  text-decoration: underline;
}

/* ============================================
   HEADER & NAVIGATION
   ============================================ */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background-color: var(--color-text-light);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
  z-index: 1000;
  transition: all 0.3s ease;
}

.header__container {
  max-width: var(--max-width-content);
  margin: 0 auto;
  padding: 0 var(--spacing-md);
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.header__logo {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.header__logo-text {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-bg-main);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  text-decoration: none;
}

.header__logo-text:hover {
  text-decoration: none;
  opacity: 0.8;
}

.header__tagline {
  font-size: 0.75rem;
  font-weight: 300;
  color: #666;
  font-family: var(--font-body);
  text-transform: none;
  letter-spacing: normal;
}

/* Main Navigation */
.nav {
  display: flex;
  gap: var(--spacing-md);
}

.nav__list {
  display: flex;
  gap: var(--spacing-md);
  list-style: none;
  align-items: center;
}

.nav__link {
  font-size: 0.95rem;
  font-weight: 400;
  color: var(--color-text-main);
  text-decoration: none;
  padding-bottom: 4px;
  border-bottom: 2px solid transparent;
  transition: all 0.3s ease;
}

.nav__link:hover,
.nav__link.active {
  color: var(--color-bg-main);
  border-bottom-color: var(--color-bg-main);
  text-decoration: none;
}

/* Mobile Menu Toggle */
.mobile-menu-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--spacing-xs);
  z-index: 1001;
  position: relative;
}

.mobile-menu-toggle span {
  display: block;
  width: 28px;
  height: 3px;
  background-color: var(--color-bg-main);
  margin: 5px 0;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  border-radius: 2px;
}

.mobile-menu-toggle:hover span {
  background-color: var(--color-link-hover);
}

/* Drawer Close Button */
.drawer-close {
  display: none;
  position: absolute;
  top: var(--spacing-md);
  right: var(--spacing-md);
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--spacing-xs);
  color: var(--color-text-light);
  font-size: 2rem;
  line-height: 1;
  font-weight: 300;
  opacity: 0.9;
  transition: all 0.3s ease;
  z-index: 10;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.drawer-close:hover {
  opacity: 1;
  transform: rotate(90deg) scale(1.1);
  background-color: rgba(255, 255, 255, 0.1);
}

/* Drawer Header */
.drawer-header {
  display: none;
  padding: var(--spacing-md);
  border-bottom: 1px solid #f0f0f0;
  background-color: var(--color-accent);
}

.drawer-header__title {
  font-family: var(--font-heading);
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-bg-main);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin: 0;
}

/* ============================================
   HERO SECTION
   ============================================ */
.hero {
  min-height: 90vh;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  margin-top: var(--header-height);
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(to top, rgba(14, 57, 83, 0.7) 0%, rgba(14, 57, 83, 0.3) 50%, rgba(14, 57, 83, 0.5) 100%);
}

.hero__content {
  position: relative;
  z-index: 1;
  max-width: var(--max-width-content);
  padding: 0 var(--spacing-md);
  color: var(--color-text-light);
  text-align: center;
}

.hero__subtitle {
  font-size: 0.95rem;
  font-weight: 300;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  margin-bottom: var(--spacing-sm);
  opacity: 0.95;
}

.hero__title {
  font-size: clamp(3rem, 5vw, 3.5rem);
  font-family: var(--font-heading);
  font-weight: 700;
  margin-bottom: var(--spacing-sm);
  text-transform: uppercase;
  letter-spacing: 0.02em;
  color: var(--color-text-light);
}

.hero__description {
  font-size: clamp(1.1rem, 2vw, 1.5rem);
  font-weight: 300;
  max-width: 800px;
  margin: 0 auto;
  opacity: 0.9;
  line-height: 1.6;
}

/* ============================================
   NAVIGATION BLOCKS (Home Page)
   ============================================ */
.nav-blocks {
  display: flex;
  flex-direction: column;
}

.nav-block {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 80px;
  padding: var(--spacing-sm);
  cursor: pointer;
  transition: all 0.3s ease;
  text-decoration: none;
}

.nav-block:nth-child(1) {
  background-color: var(--color-nav-block-1);
}

.nav-block:nth-child(2) {
  background-color: var(--color-nav-block-2);
}

.nav-block:nth-child(3) {
  background-color: var(--color-nav-block-3);
}

.nav-block:hover {
  background-color: var(--color-bg-main);
}

.nav-block__content {
  max-width: var(--max-width-content);
  width: 100%;
  padding: 0 var(--spacing-md);
}

.nav-block__text {
  font-size: clamp(1.25rem, 2.5vw, 1.5rem);
  font-weight: 300;
  color: var(--color-text-light);
  letter-spacing: 0.01em;
  margin-bottom: 0;
}

/* ============================================
   CONTENT SECTIONS
   ============================================ */
.section {
  padding: var(--spacing-xl) var(--spacing-md);
}

.section--accent {
  background-color: var(--color-accent);
}

.section--dark {
  background-color: var(--color-bg-main);
  color: var(--color-text-light);
}

.container {
  max-width: var(--max-width-content);
  margin: 0 auto;
}

.container--narrow {
  max-width: var(--max-width-text);
  margin: 0 auto;
}

/* Page Hero (smaller than homepage hero) */
.page-hero {
  height: 400px;
  display: flex;
  align-items: end;
  justify-content: center;
  background-size: cover;
  background-position: center;
  position: relative;
  margin-top: var(--header-height);
  padding-bottom: 25px;
}

.page-hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(to bottom, rgba(14, 57, 83, 0.6), rgba(14, 57, 83, 0.8));
}

.page-hero__content {
  position: relative;
  z-index: 1;
  text-align: center;
  color: var(--color-text-light);
}

.page-hero__title {
  font-size: clamp(2.5rem, 5vw, 4rem);
  color: var(--color-text-light);
  margin-bottom: 0;
}

/* ============================================
   CONTENT BLOCKS
   ============================================ */
.content-block {
  margin: var(--spacing-md) 0;
}

.content-block__image {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
  margin-bottom: var(--spacing-md);
}

.content-block__text {
  font-size: 1.05rem;
  line-height: 1.8;
  color: var(--color-text-main);
}

.content-block__text p {
  margin-bottom: var(--spacing-md);
}

/* ============================================
   BLOG LIST
   ============================================ */
.blog-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
}

.blog-item {
  display: grid;
  grid-template-columns: 1fr 400px;
  gap: var(--spacing-lg);
  align-items: start;
  padding-bottom: var(--spacing-lg);
  border-bottom: 1px solid #e0e0e0;
}

.blog-item:last-child {
  border-bottom: none;
}

.blog-item__content {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.blog-item__title {
  font-size: 1.75rem;
  margin-bottom: var(--spacing-xs);
}

.blog-item__title a {
  color: var(--color-text-main);
  text-decoration: none;
  transition: color 0.3s ease;
}

.blog-item__title a:hover {
  color: var(--color-bg-main);
}

.blog-item__excerpt {
  color: #666;
  line-height: 1.7;
}

.blog-item__meta {
  font-size: 0.9rem;
  color: #999;
  margin-bottom: var(--spacing-xs);
}

.blog-item__link {
  display: inline-block;
  margin-top: var(--spacing-xs);
  font-weight: 400;
  color: var(--color-bg-main);
}

.blog-item__image-wrapper {
  position: relative;
  overflow: hidden;
  border-radius: 8px;
  aspect-ratio: 4/3;
}

.blog-item__image {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.3s ease;
}

.blog-item:hover .blog-item__image {
  transform: scale(1.05);
}

/* ============================================
   ORDER / PURCHASE SECTION
   ============================================ */
.order-section {
  display: grid;
  grid-template-columns: 1fr 1.5fr;
  gap: var(--spacing-lg);
  align-items: center;
  margin: var(--spacing-lg) 0;
}

.order-section__image {
  width: 100%;
  max-width: 400px;
  height: auto;
  border-radius: 8px;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.15);
}

.order-section__content {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.order-section__title {
  font-size: 2rem;
  margin-bottom: var(--spacing-sm);
}

.order-section__description {
  line-height: 1.8;
  color: #666;
}

.order-section__meta {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
  padding: var(--spacing-md);
  background-color: var(--color-accent);
  border-radius: 8px;
  font-size: 0.95rem;
}

/* Purchase Links */
.purchase-links {
  margin-top: var(--spacing-lg);
}

.purchase-links__title {
  font-size: 1.25rem;
  margin-bottom: var(--spacing-md);
  text-align: center;
}

.purchase-links__list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.purchase-link {
  display: block;
  padding: var(--spacing-sm) var(--spacing-md);
  background-color: var(--color-bg-main);
  color: var(--color-text-light);
  text-align: center;
  border-radius: 6px;
  font-weight: 500;
  text-decoration: none;
  transition: all 0.3s ease;
}

.purchase-link:hover {
  background-color: var(--color-link-hover);
  text-decoration: none;
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(14, 57, 83, 0.3);
}

/* ============================================
   CONTACT SECTION
   ============================================ */
.contact-box {
  max-width: 600px;
  margin: var(--spacing-lg) auto;
  padding: var(--spacing-lg);
  background-color: var(--color-accent);
  border-radius: 8px;
  text-align: center;
}

.contact-box__title {
  font-size: 1.5rem;
  margin-bottom: var(--spacing-md);
}

.contact-box__info {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
  font-size: 1.05rem;
  line-height: 1.8;
}

.contact-box__item {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-xs);
}

.contact-box__label {
  font-weight: 500;
  color: var(--color-text-main);
}

.contact-box__value {
  color: #666;
}

/* Contact Form */
.contact-form {
  max-width: 600px;
  margin: var(--spacing-lg) auto;
}

.form-group {
  margin-bottom: var(--spacing-md);
}

.form-label {
  display: block;
  margin-bottom: var(--spacing-xs);
  font-weight: 500;
  color: var(--color-text-main);
}

.form-input,
.form-textarea {
  width: 100%;
  padding: var(--spacing-sm);
  border: 1px solid #ddd;
  border-radius: 6px;
  font-family: var(--font-body);
  font-size: 1rem;
  background-color: var(--color-text-light);
  transition: border-color 0.3s ease;
}

.form-input:focus,
.form-textarea:focus {
  outline: none;
  border-color: var(--color-bg-main);
}

.form-textarea {
  min-height: 150px;
  resize: vertical;
}

.form-submit {
  width: 100%;
  padding: var(--spacing-sm) var(--spacing-md);
  background-color: var(--color-bg-main);
  color: var(--color-text-light);
  border: none;
  border-radius: 6px;
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.3s ease;
}

.form-submit:hover {
  background-color: var(--color-link-hover);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(14, 57, 83, 0.3);
}

/* ============================================
   BREADCRUMB
   ============================================ */
.breadcrumb {
  padding: var(--spacing-md) 0;
  font-size: 0.9rem;
}

.breadcrumb a {
  color: #999;
}

.breadcrumb a:hover {
  color: var(--color-bg-main);
}

.breadcrumb__separator {
  margin: 0 var(--spacing-xs);
  color: #ccc;
}

.breadcrumb__current {
  color: var(--color-text-main);
}

/* ============================================
   RELATED POSTS
   ============================================ */
.related-posts {
  margin-top: var(--spacing-xl);
  padding-top: var(--spacing-lg);
  border-top: 2px solid #e0e0e0;
}

.related-posts__title {
  font-size: 1.75rem;
  margin-bottom: var(--spacing-lg);
}

.related-posts__list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--spacing-md);
}

.related-post {
  text-decoration: none;
  color: var(--color-text-main);
}

.related-post__image {
  width: 100%;
  height: 200px;
  object-fit: cover;
  border-radius: 8px;
  margin-bottom: var(--spacing-sm);
}

.related-post__title {
  font-size: 1.1rem;
  font-weight: 500;
  margin-bottom: var(--spacing-xs);
}

.related-post:hover .related-post__title {
  color: var(--color-bg-main);
}

/* Back Button */
.back-button {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  margin: var(--spacing-lg) 0;
  font-weight: 400;
  color: var(--color-bg-main);
  text-decoration: none;
}

.back-button:hover {
  text-decoration: underline;
}

/* ============================================
   FOOTER
   ============================================ */
.footer {
  background-color: var(--color-bg-main);
  color: var(--color-text-light);
  padding: var(--spacing-lg) var(--spacing-md);
  text-align: center;
}

.footer__container {
  max-width: var(--max-width-content);
  margin: 0 auto;
}

.footer__content {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
  font-size: 0.9rem;
  opacity: 0.9;
}

.footer__links {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
  list-style: none;
}

.footer__link {
  color: var(--color-text-light);
  text-decoration: none;
  opacity: 0.8;
  transition: opacity 0.3s ease;
}

.footer__link:hover {
  opacity: 1;
  text-decoration: underline;
}

/* ============================================
   UTILITY CLASSES
   ============================================ */
.text-center {
  text-align: center;
}

.mt-sm { margin-top: var(--spacing-sm); }
.mt-md { margin-top: var(--spacing-md); }
.mt-lg { margin-top: var(--spacing-lg); }
.mt-xl { margin-top: var(--spacing-xl); }

.mb-sm { margin-bottom: var(--spacing-sm); }
.mb-md { margin-bottom: var(--spacing-md); }
.mb-lg { margin-bottom: var(--spacing-lg); }
.mb-xl { margin-bottom: var(--spacing-xl); }

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

/* Tablet (1024px and below) */
@media (max-width: 1024px) {
  :root {
    --max-width-content: 960px;
    --spacing-lg: 48px;
    --spacing-xl: 72px;
  }
  
  .order-section {
    grid-template-columns: 1fr;
  }
  
  .order-section__image {
    max-width: 100%;
    margin: 0 auto;
  }
  
  .blog-item {
    grid-template-columns: 1fr 300px;
    gap: var(--spacing-md);
  }
}

/* Mobile (768px and below) */
@media (max-width: 768px) {
  :root {
    --header-height: 70px;
    --spacing-md: 24px;
    --spacing-lg: 40px;
    --spacing-xl: 56px;
  }
  
  /* Mobile Navigation */
  .mobile-menu-toggle {
    display: block;
  }
  
  /* Show drawer elements on mobile */
  .drawer-close {
    display: block;
  }
  
  /* Hide drawer header on mobile for cleaner look */
  .drawer-header {
    display: none;
  }
  
  /* Mobile Menu Overlay */
  .nav::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(14, 57, 83, 0.75);
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    z-index: -1;
  }
  
  .nav.active::before {
    opacity: 1;
    visibility: visible;
  }
  
  /* Professional Drawer Navigation */
  .nav {
    position: fixed;
    top: 0;
    right: 0;
    transform: translate(120%, -50%);
    width: 100%;
    min-height: 100vh;
    max-height: 100vh;
    background-color: #2A2A2A;
    border: 3px solid var(--color-text-light);
    border-radius: 0;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.4);
    visibility: hidden;
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    z-index: 1100;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
  }
  
  .nav.active {
    transform: translate(0);
    visibility: visible;
  }
  
  .nav__list {
    flex-direction: column;
    padding: var(--spacing-xl) var(--spacing-lg);
    gap: 1px;
    height: auto;
    flex: 1;
    justify-content: center;
    align-items: stretch;
  }
  
  .nav__item {
    width: 100%;
    border-bottom: none;
  }
  
  .nav__link {
    display: block;
    padding: 4px var(--spacing-md);
    border-bottom: none;
    font-size: 1.68rem;
    font-weight: 600;
    font-family: var(--font-body);
    color: var(--color-text-light);
    text-align: left;
    transition: all 0.3s ease;
    position: relative;
  }
  
  .nav__link:hover {
    color: var(--color-text-light);
    background-color: rgba(255, 255, 255, 0.1);
    text-decoration: none;
    transform: translateX(-5px);
  }
  
  .nav__link.active {
    color: var(--color-text-light);
    background-color: var(--color-bg-main);
    text-decoration: none;
  }
  
  /* Hero adjustments */
  .hero {
    min-height: 52vh;
  }
  
  .page-hero {
    height: 300px;
  }
  
  /* Blog items stack */
  .blog-item {
    grid-template-columns: 1fr;
    gap: var(--spacing-sm);
  }
  
  .blog-item__image-wrapper {
    order: -1;
  }
  
  /* Navigation blocks */
  .nav-block {
    min-height: 70px;
  }
  
  /* Content sections */
  .section {
    padding: var(--spacing-lg) var(--spacing-md);
  }
  
  /* Related posts */
  .related-posts__list {
    grid-template-columns: 1fr;
  }
}

/* Small mobile (480px and below) */
@media (max-width: 480px) {
  .header__tagline {
    display: none;
  }
  
  .hero__title {
    font-size: 2.5rem;
  }
  
  .nav-block__text {
    font-size: 1.1rem;
  }
}

/* ============================================
   ANIMATIONS
   ============================================ */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in {
  animation: fadeIn 0.6s ease forwards;
}

/* Print styles */
@media print {
  .header,
  .nav,
  .mobile-menu-toggle,
  .footer {
    display: none;
  }
  
  .hero,
  .page-hero {
    margin-top: 0;
  }
}