/* ============================================================
   TRINH HUU THO - AI ENGINEER PORTFOLIO
   Main Stylesheet
   ============================================================ */

/* ---- CSS Custom Properties ---- */
:root {
  /* Colors - Light mode */
  --bg-primary: #ffffff;
  --bg-secondary: #f8f9fa;
  --bg-card: #ffffff;
  --text-primary: #1a1a2e;
  --text-secondary: #4a5568;
  --text-muted: #718096;
  --accent: #6c63ff;
  --accent-hover: #5a52d5;
  --accent-secondary: #ff6584;
  --border: #e2e8f0;
  --shadow: rgba(0, 0, 0, 0.08);
  --shadow-hover: rgba(108, 99, 255, 0.2);
  --code-bg: #f6f8fa;
  --nav-bg: rgba(255, 255, 255, 0.95);
  --tag-bg: #eef2ff;
  --tag-text: #6c63ff;

  /* Typography */
  --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
  --font-mono: 'Fira Code', 'Cascadia Code', monospace;

  /* Spacing */
  --section-padding: 80px 0;
  --container-max: 1200px;

  /* Transitions */
  --transition: 0.3s ease;
  --transition-slow: 0.5s ease;
}

/* Dark mode */
[data-theme="dark"] {
  --bg-primary: #0f0f1a;
  --bg-secondary: #16162a;
  --bg-card: #1e1e35;
  --text-primary: #e2e8f0;
  --text-secondary: #a0aec0;
  --text-muted: #718096;
  --accent: #7c73ff;
  --accent-hover: #9189ff;
  --border: #2d2d4a;
  --shadow: rgba(0, 0, 0, 0.3);
  --shadow-hover: rgba(124, 115, 255, 0.25);
  --code-bg: #1a1a2e;
  --nav-bg: rgba(15, 15, 26, 0.95);
  --tag-bg: #2d2d4a;
  --tag-text: #9189ff;
}

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

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.7;
  transition: background-color var(--transition), color var(--transition);
}

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

a:hover {
  color: var(--accent-hover);
}

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

ul {
  list-style: none;
}

/* ---- Typography ---- */
h1, h2, h3, h4, h5, h6 {
  line-height: 1.3;
  font-weight: 700;
  color: var(--text-primary);
}

h1 { font-size: clamp(2rem, 5vw, 3.5rem); }
h2 { font-size: clamp(1.6rem, 3vw, 2.5rem); }
h3 { font-size: clamp(1.2rem, 2.5vw, 1.75rem); }
h4 { font-size: 1.25rem; }

p {
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

/* ---- Utility Classes ---- */
.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: var(--section-padding);
}

.section-header {
  text-align: center;
  margin-bottom: 60px;
}

.section-header h2 {
  position: relative;
  display: inline-block;
  margin-bottom: 16px;
}

.section-header h2::after {
  content: '';
  position: absolute;
  bottom: -8px;
  left: 50%;
  transform: translateX(-50%);
  width: 60px;
  height: 4px;
  background: linear-gradient(90deg, var(--accent), var(--accent-secondary));
  border-radius: 2px;
}

.section-header p {
  font-size: 1.1rem;
  max-width: 600px;
  margin: 0 auto;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  transition: all var(--transition);
  border: 2px solid transparent;
  text-decoration: none;
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--accent-secondary));
  color: #fff;
  box-shadow: 0 4px 15px var(--shadow-hover);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px var(--shadow-hover);
  color: #fff;
}

.btn-outline {
  background: transparent;
  color: var(--accent);
  border-color: var(--accent);
}

.btn-outline:hover {
  background: var(--accent);
  color: #fff;
  transform: translateY(-2px);
}

.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
  border-color: var(--border);
}

.btn-ghost:hover {
  background: var(--bg-secondary);
  color: var(--text-primary);
}

.tag {
  display: inline-flex;
  align-items: center;
  padding: 4px 12px;
  background: var(--tag-bg);
  color: var(--tag-text);
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 600;
  transition: all var(--transition);
}

.tag:hover {
  background: var(--accent);
  color: #fff;
  cursor: pointer;
}

.tag.active {
  background: var(--accent);
  color: #fff;
}

/* Fade-in animation */
.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

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

/* ---- Navigation ---- */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: var(--nav-bg);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  transition: all var(--transition);
}

.navbar.scrolled {
  box-shadow: 0 2px 20px var(--shadow);
}

.nav-container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 70px;
}

.nav-logo {
  font-size: 1.5rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--accent), var(--accent-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  text-decoration: none;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav-link {
  padding: 8px 14px;
  border-radius: 8px;
  font-weight: 500;
  color: var(--text-secondary);
  transition: all var(--transition);
  font-size: 0.95rem;
}

.nav-link:hover,
.nav-link.active {
  color: var(--accent);
  background: var(--tag-bg);
}

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

.theme-toggle {
  width: 40px;
  height: 40px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg-secondary);
  color: var(--text-primary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  transition: all var(--transition);
}

.theme-toggle:hover {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 8px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: none;
}

.hamburger span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-primary);
  transition: all var(--transition);
}

/* Mobile nav */
@media (max-width: 768px) {
  .nav-menu {
    display: none;
    position: absolute;
    top: 70px;
    left: 0;
    right: 0;
    background: var(--nav-bg);
    backdrop-filter: blur(12px);
    flex-direction: column;
    padding: 16px 24px;
    border-bottom: 1px solid var(--border);
    gap: 4px;
  }

  .nav-menu.open {
    display: flex;
  }

  .nav-link {
    width: 100%;
    padding: 12px 16px;
  }

  .hamburger {
    display: flex;
  }

  .hamburger.active span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
  }
  .hamburger.active span:nth-child(2) {
    opacity: 0;
  }
  .hamburger.active span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
  }
}

/* ---- Hero Section ---- */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding: 100px 0 80px;
  position: relative;
  overflow: hidden;
}

/* Animated background grid */
.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(var(--border) 1px, transparent 1px),
    linear-gradient(90deg, var(--border) 1px, transparent 1px);
  background-size: 50px 50px;
  opacity: 0.4;
  z-index: 0;
}

.hero-content {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1fr 400px;
  gap: 60px;
  align-items: center;
}

.hero-text {
  max-width: 600px;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  background: var(--tag-bg);
  color: var(--tag-text);
  border-radius: 20px;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 20px;
  border: 1px solid var(--border);
}

.hero-badge::before {
  content: '';
  width: 8px;
  height: 8px;
  background: #22c55e;
  border-radius: 50%;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.4; }
}

.hero-title {
  margin-bottom: 8px;
}

.hero-title .name {
  display: block;
  background: linear-gradient(135deg, var(--accent), var(--accent-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: clamp(1.1rem, 2vw, 1.4rem);
  color: var(--text-secondary);
  margin-bottom: 20px;
  font-weight: 500;
}

.hero-description {
  font-size: 1.05rem;
  line-height: 1.8;
  margin-bottom: 32px;
  color: var(--text-secondary);
}

.hero-cta {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 40px;
}

.hero-social {
  display: flex;
  gap: 12px;
}

.social-link {
  width: 42px;
  height: 42px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg-card);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  font-size: 1.1rem;
  transition: all var(--transition);
  text-decoration: none;
}

.social-link:hover {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
  transform: translateY(-3px);
}

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

.avatar-container {
  position: relative;
  width: 320px;
  height: 320px;
}

.avatar-bg {
  position: absolute;
  inset: 0;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), var(--accent-secondary));
  animation: rotate 10s linear infinite;
  opacity: 0.15;
}

.avatar-ring {
  position: absolute;
  inset: 10px;
  border-radius: 50%;
  border: 3px dashed var(--accent);
  opacity: 0.4;
  animation: rotate 20s linear infinite reverse;
}

.avatar-img {
  position: absolute;
  inset: 20px;
  border-radius: 50%;
  overflow: hidden;
  background: var(--bg-secondary);
  border: 4px solid var(--bg-card);
  box-shadow: 0 20px 60px var(--shadow);
}

.avatar-img img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.avatar-placeholder {
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, var(--bg-secondary), var(--tag-bg));
  color: var(--accent);
  font-size: 3rem;
  font-weight: 800;
}

@keyframes rotate {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

@media (max-width: 900px) {
  .hero-content {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .hero-cta {
    justify-content: center;
  }

  .hero-social {
    justify-content: center;
  }

  .hero-image {
    order: -1;
  }

  .avatar-container {
    width: 240px;
    height: 240px;
  }
}

/* ---- Stats Bar ---- */
.stats-bar {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  padding: 40px 0;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  text-align: center;
}

.stat-item {
  padding: 20px;
}

.stat-number {
  font-size: 2.5rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--accent), var(--accent-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  display: block;
}

.stat-label {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-top: 4px;
}

@media (max-width: 600px) {
  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* ---- About Section ---- */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: start;
}

.about-text h3 {
  margin-bottom: 16px;
}

.about-text p {
  margin-bottom: 16px;
  font-size: 1.05rem;
  line-height: 1.8;
}

.experience-list {
  margin-top: 24px;
}

.experience-item {
  display: flex;
  gap: 16px;
  margin-bottom: 24px;
  padding: 20px;
  background: var(--bg-card);
  border-radius: 12px;
  border: 1px solid var(--border);
  transition: all var(--transition);
}

.experience-item:hover {
  border-color: var(--accent);
  transform: translateX(4px);
}

.experience-icon {
  width: 48px;
  height: 48px;
  border-radius: 10px;
  background: var(--tag-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  flex-shrink: 0;
}

.experience-info h4 {
  font-size: 1rem;
  margin-bottom: 4px;
}

.experience-info .company {
  color: var(--accent);
  font-size: 0.9rem;
  font-weight: 600;
}

.experience-info .period {
  color: var(--text-muted);
  font-size: 0.85rem;
}

/* Skills */
.skills-section h3 {
  margin-bottom: 24px;
}

.skill-category {
  margin-bottom: 24px;
}

.skill-category-title {
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-muted);
  margin-bottom: 12px;
}

.skills-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.skill-tag {
  padding: 6px 14px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 20px;
  font-size: 0.85rem;
  color: var(--text-secondary);
  transition: all var(--transition);
}

.skill-tag:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--tag-bg);
}

@media (max-width: 768px) {
  .about-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }
}

/* ---- Projects Section ---- */
.filter-bar {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  justify-content: center;
  margin-bottom: 40px;
}

.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 28px;
}

.project-card {
  background: var(--bg-card);
  border-radius: 16px;
  border: 1px solid var(--border);
  overflow: hidden;
  transition: all var(--transition);
  position: relative;
}

.project-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 20px 40px var(--shadow);
  border-color: var(--accent);
}

.project-card.hidden {
  display: none;
}

.project-thumbnail {
  aspect-ratio: 16/9;
  background: linear-gradient(135deg, var(--bg-secondary), var(--tag-bg));
  overflow: hidden;
  position: relative;
}

.project-thumbnail img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--transition-slow);
}

.project-card:hover .project-thumbnail img {
  transform: scale(1.05);
}

.project-thumbnail-placeholder {
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 3rem;
  background: linear-gradient(135deg, var(--bg-secondary), var(--tag-bg));
}

.project-body {
  padding: 24px;
}

.project-tags {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  margin-bottom: 12px;
}

.project-title {
  font-size: 1.15rem;
  margin-bottom: 8px;
}

.project-desc {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: 16px;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.project-tech {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 20px;
}

.tech-badge {
  padding: 2px 8px;
  background: var(--code-bg);
  color: var(--text-muted);
  border-radius: 4px;
  font-size: 0.78rem;
  font-family: var(--font-mono);
  border: 1px solid var(--border);
}

.project-links {
  display: flex;
  gap: 10px;
}

.project-link {
  flex: 1;
  text-align: center;
  padding: 8px 16px;
  border-radius: 8px;
  font-size: 0.85rem;
  font-weight: 600;
  border: 1px solid var(--border);
  color: var(--text-secondary);
  transition: all var(--transition);
}

.project-link:hover {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

.project-link.primary {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

.project-link.primary:hover {
  background: var(--accent-hover);
}

/* ---- Blog Section ---- */
.blog-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 28px;
  margin-bottom: 48px;
}

.blog-card {
  background: var(--bg-card);
  border-radius: 16px;
  border: 1px solid var(--border);
  overflow: hidden;
  transition: all var(--transition);
  text-decoration: none;
  display: flex;
  flex-direction: column;
}

.blog-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 20px 40px var(--shadow);
  border-color: var(--accent);
}

.blog-thumbnail {
  aspect-ratio: 16/9;
  overflow: hidden;
  background: linear-gradient(135deg, var(--bg-secondary), var(--tag-bg));
}

.blog-thumbnail-placeholder {
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2.5rem;
}

.blog-body {
  padding: 24px;
  flex: 1;
  display: flex;
  flex-direction: column;
}

.blog-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 12px;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.blog-meta .dot {
  width: 4px;
  height: 4px;
  background: var(--text-muted);
  border-radius: 50%;
}

.blog-title {
  font-size: 1.1rem;
  margin-bottom: 10px;
  color: var(--text-primary);
  flex: 1;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.blog-excerpt {
  font-size: 0.9rem;
  color: var(--text-muted);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  margin-bottom: 16px;
}

.blog-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.read-more {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--accent);
  display: flex;
  align-items: center;
  gap: 4px;
}

.read-more::after {
  content: '→';
  transition: transform var(--transition);
}

.blog-card:hover .read-more::after {
  transform: translateX(4px);
}

/* ---- Blog Listing Page ---- */
.blog-search-bar {
  max-width: 600px;
  margin: 0 auto 32px;
  position: relative;
}

.blog-search-bar input {
  width: 100%;
  padding: 14px 20px 14px 50px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--bg-card);
  color: var(--text-primary);
  font-size: 1rem;
  font-family: var(--font-sans);
  transition: all var(--transition);
}

.blog-search-bar input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(108, 99, 255, 0.1);
}

.blog-search-bar .search-icon {
  position: absolute;
  left: 16px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
  font-size: 1.1rem;
  pointer-events: none;
}

/* ---- Blog Post Page ---- */
.post-hero {
  padding: 120px 0 60px;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border);
}

.post-hero .container {
  max-width: 800px;
}

.post-meta {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 20px;
  flex-wrap: wrap;
}

.post-category {
  padding: 4px 12px;
  background: var(--accent);
  color: #fff;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 600;
}

.post-date, .post-read-time {
  color: var(--text-muted);
  font-size: 0.9rem;
}

.post-title {
  margin-bottom: 20px;
}

.post-subtitle {
  font-size: 1.1rem;
  color: var(--text-secondary);
  margin-bottom: 24px;
}

.post-author {
  display: flex;
  align-items: center;
  gap: 12px;
}

.author-avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  overflow: hidden;
  background: var(--tag-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
}

.author-name {
  font-weight: 600;
  font-size: 0.95rem;
}

.author-title {
  color: var(--text-muted);
  font-size: 0.85rem;
}

/* Post content */
.post-content {
  padding: 60px 0;
}

.post-body {
  max-width: 800px;
  margin: 0 auto;
}

.post-body h2 {
  margin: 40px 0 16px;
  font-size: 1.8rem;
}

.post-body h3 {
  margin: 32px 0 12px;
  font-size: 1.4rem;
}

.post-body p {
  font-size: 1.05rem;
  line-height: 1.9;
  margin-bottom: 20px;
}

.post-body ul, .post-body ol {
  margin: 16px 0 20px 24px;
  list-style: disc;
}

.post-body ol {
  list-style: decimal;
}

.post-body li {
  margin-bottom: 8px;
  color: var(--text-secondary);
  font-size: 1.05rem;
  line-height: 1.7;
}

.post-body pre {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 24px;
  overflow-x: auto;
  margin: 24px 0;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  line-height: 1.6;
}

.post-body code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 2px 6px;
  color: var(--accent);
}

.post-body pre code {
  background: none;
  border: none;
  padding: 0;
  color: inherit;
}

.post-body blockquote {
  border-left: 4px solid var(--accent);
  margin: 24px 0;
  padding: 16px 24px;
  background: var(--tag-bg);
  border-radius: 0 12px 12px 0;
  font-style: italic;
}

.post-body img {
  border-radius: 12px;
  margin: 24px 0;
  box-shadow: 0 8px 30px var(--shadow);
}

.post-share {
  border-top: 1px solid var(--border);
  padding-top: 40px;
  margin-top: 60px;
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.post-share span {
  font-weight: 600;
  color: var(--text-primary);
}

.share-btn {
  padding: 8px 16px;
  border-radius: 8px;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  border: 1px solid var(--border);
  background: var(--bg-card);
  color: var(--text-secondary);
  transition: all var(--transition);
  display: flex;
  align-items: center;
  gap: 6px;
}

.share-btn:hover {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

/* Post navigation */
.post-nav {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  margin-top: 60px;
  padding-top: 40px;
  border-top: 1px solid var(--border);
}

.post-nav-link {
  padding: 20px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  transition: all var(--transition);
  text-decoration: none;
}

.post-nav-link:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}

.post-nav-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 6px;
}

.post-nav-title {
  font-weight: 600;
  color: var(--text-primary);
  font-size: 0.95rem;
}

.post-nav-link.next {
  text-align: right;
}

/* Pagination */
.pagination {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin-top: 48px;
}

.page-btn {
  width: 40px;
  height: 40px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg-card);
  color: var(--text-secondary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  font-size: 0.9rem;
  transition: all var(--transition);
  text-decoration: none;
}

.page-btn:hover, .page-btn.active {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

/* ---- Guestbook Section ---- */
.guestbook-intro {
  text-align: center;
  max-width: 600px;
  margin: 0 auto 40px;
}

.guestbook-container {
  max-width: 800px;
  margin: 0 auto;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 16px;
  overflow: hidden;
}

.guestbook-header {
  padding: 24px 28px;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 12px;
}

.guestbook-icon {
  font-size: 1.5rem;
}

.guestbook-header h3 {
  font-size: 1.1rem;
}

.guestbook-body {
  padding: 8px;
}

/* ---- Contact Section ---- */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1.5fr;
  gap: 60px;
  align-items: start;
}

.contact-info h3 {
  margin-bottom: 16px;
}

.contact-info p {
  margin-bottom: 32px;
  font-size: 1.05rem;
  line-height: 1.8;
}

.contact-methods {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.contact-method {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 16px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  text-decoration: none;
  color: var(--text-secondary);
  transition: all var(--transition);
}

.contact-method:hover {
  border-color: var(--accent);
  color: var(--accent);
  transform: translateX(4px);
}

.contact-method-icon {
  width: 44px;
  height: 44px;
  border-radius: 10px;
  background: var(--tag-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
  flex-shrink: 0;
}

.contact-method-info .label {
  font-size: 0.8rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.contact-method-info .value {
  font-weight: 600;
  font-size: 0.95rem;
}

/* Contact Form */
.contact-form {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 32px;
}

.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  margin-bottom: 8px;
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--text-primary);
}

.form-group input,
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--bg-primary);
  color: var(--text-primary);
  font-size: 0.95rem;
  font-family: var(--font-sans);
  transition: all var(--transition);
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(108, 99, 255, 0.1);
}

.form-group textarea {
  resize: vertical;
  min-height: 120px;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.form-success {
  display: none;
  padding: 16px;
  background: #dcfce7;
  color: #166534;
  border-radius: 10px;
  margin-top: 16px;
  text-align: center;
  font-weight: 600;
}

[data-theme="dark"] .form-success {
  background: #052e16;
  color: #86efac;
}

@media (max-width: 768px) {
  .contact-grid {
    grid-template-columns: 1fr;
  }

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

/* ---- Footer ---- */
.footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border);
  padding: 60px 0 30px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 48px;
}

.footer-brand p {
  margin-top: 12px;
  font-size: 0.9rem;
  color: var(--text-muted);
  max-width: 280px;
}

.footer-social {
  display: flex;
  gap: 10px;
  margin-top: 16px;
}

.footer-col h4 {
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-muted);
  margin-bottom: 16px;
}

.footer-col ul {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-col ul li a {
  color: var(--text-secondary);
  font-size: 0.9rem;
  transition: color var(--transition);
}

.footer-col ul li a:hover {
  color: var(--accent);
}

.footer-bottom {
  border-top: 1px solid var(--border);
  padding-top: 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.85rem;
  color: var(--text-muted);
}

@media (max-width: 768px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }

  .footer-bottom {
    flex-direction: column;
    gap: 8px;
    text-align: center;
  }
}

@media (max-width: 480px) {
  .footer-grid {
    grid-template-columns: 1fr;
  }
}

/* ---- Timeline (About page) ---- */
.timeline {
  position: relative;
  padding-left: 40px;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 8px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: linear-gradient(to bottom, var(--accent), transparent);
}

.timeline-item {
  position: relative;
  margin-bottom: 40px;
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: -36px;
  top: 6px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--accent);
  border: 3px solid var(--bg-primary);
  box-shadow: 0 0 0 2px var(--accent);
}

.timeline-date {
  font-size: 0.8rem;
  color: var(--accent);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 6px;
}

.timeline-title {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 4px;
}

.timeline-company {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: 10px;
}

.timeline-desc {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ---- Certifications ---- */
.cert-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 20px;
}

.cert-card {
  padding: 20px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  transition: all var(--transition);
}

.cert-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}

.cert-icon {
  font-size: 1.8rem;
  margin-bottom: 12px;
}

.cert-name {
  font-weight: 700;
  font-size: 0.95rem;
  margin-bottom: 4px;
}

.cert-issuer {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.cert-year {
  font-size: 0.8rem;
  color: var(--accent);
  font-weight: 600;
  margin-top: 8px;
}

/* ---- Page Hero (for inner pages) ---- */
.page-hero {
  padding: 120px 0 60px;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border);
  text-align: center;
}

.page-hero h1 {
  margin-bottom: 12px;
}

.page-hero p {
  font-size: 1.1rem;
  max-width: 500px;
  margin: 0 auto;
}

/* ---- Back to top ---- */
.back-to-top {
  position: fixed;
  bottom: 24px;
  right: 24px;
  width: 44px;
  height: 44px;
  border-radius: 10px;
  background: var(--accent);
  color: #fff;
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  box-shadow: 0 4px 12px var(--shadow-hover);
  transition: all var(--transition);
  opacity: 0;
  pointer-events: none;
  z-index: 999;
}

.back-to-top.visible {
  opacity: 1;
  pointer-events: auto;
}

.back-to-top:hover {
  transform: translateY(-3px);
  background: var(--accent-hover);
}

/* ---- Loading Spinner ---- */
.loading {
  display: flex;
  justify-content: center;
  padding: 40px;
}

.spinner {
  width: 36px;
  height: 36px;
  border: 3px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

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

/* ---- No results ---- */
.no-results {
  text-align: center;
  padding: 60px 20px;
  color: var(--text-muted);
}

.no-results .icon {
  font-size: 3rem;
  margin-bottom: 16px;
}

/* ---- Highlight.js theme override ---- */
.hljs {
  background: var(--code-bg) !important;
  color: var(--text-primary);
  border-radius: 8px;
}

/* ---- Responsive helpers ---- */
@media (max-width: 480px) {
  .container {
    padding: 0 16px;
  }

  .section {
    padding: 60px 0;
  }

  .hero-cta {
    flex-direction: column;
  }

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

  .post-nav {
    grid-template-columns: 1fr;
  }
}

/* ---- Print styles ---- */
@media print {
  .navbar, .footer, .back-to-top, .theme-toggle {
    display: none;
  }
}