/* ============================================
   DESIGN SYSTEM — Dark Luxury Tech
   Portfolio CV: Nguyễn Ngọc Trai
   ============================================ */

/* --- CSS Variables --- */
:root {
  /* Colors */
  --bg-primary: #050508;
  --bg-secondary: #0a0f1a;
  --bg-card: rgba(15, 23, 42, 0.55);
  --bg-card-hover: rgba(15, 23, 42, 0.75);
  --bg-nav: rgba(5, 5, 8, 0.85);

  --accent: #0ea5e9;
  --accent-light: #38bdf8;
  --accent-glow: rgba(14, 165, 233, 0.3);
  --accent-purple: #8b5cf6;
  --accent-gradient: linear-gradient(135deg, #0ea5e9 0%, #8b5cf6 100%);
  --accent-gradient-text: linear-gradient(135deg, #38bdf8, #a78bfa);

  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;

  --border: rgba(148, 163, 184, 0.08);
  --border-active: rgba(14, 165, 233, 0.3);

  /* Typography */
  --font-display: 'Space Grotesk', sans-serif;
  --font-body: 'DM Sans', sans-serif;

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --space-4xl: 6rem;
  --space-5xl: 8rem;

  /* Radius */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 30px var(--accent-glow);

  /* Transitions */
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --transition-fast: 0.2s var(--ease-out);
  --transition-base: 0.4s var(--ease-out);
  --transition-slow: 0.6s var(--ease-out);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  scroll-padding-top: 80px;
}

body {
  font-family: var(--font-body);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.7;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Noise texture overlay */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.03'/%3E%3C/svg%3E");
  pointer-events: none;
  z-index: 9999;
}

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

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

ul,
ol {
  list-style: none;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: var(--font-display);
  font-weight: 600;
  line-height: 1.2;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-xl);
}

/* --- Utility Classes --- */
.gradient-text {
  background: var(--accent-gradient-text);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.section-label {
  font-family: var(--font-display);
  font-size: 0.8rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 3px;
  color: var(--accent);
  margin-bottom: var(--space-md);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.section-label::before {
  content: '';
  width: 24px;
  height: 2px;
  background: var(--accent);
  display: inline-block;
}

.section-title {
  font-size: clamp(2rem, 5vw, 3.2rem);
  font-weight: 700;
  margin-bottom: var(--space-lg);
  letter-spacing: -0.02em;
}

.section-subtitle {
  font-size: 1.1rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin-bottom: var(--space-3xl);
}

/* --- Scroll Reveal --- */
.reveal {
  opacity: 0;
  transform: translateY(40px);
  transition: opacity 0.8s var(--ease-out), transform 0.8s var(--ease-out);
}

.reveal.active {
  opacity: 1;
  transform: translateY(0);
}

.reveal-delay-1 {
  transition-delay: 0.1s;
}

.reveal-delay-2 {
  transition-delay: 0.2s;
}

.reveal-delay-3 {
  transition-delay: 0.3s;
}

.reveal-delay-4 {
  transition-delay: 0.4s;
}

.reveal-delay-5 {
  transition-delay: 0.5s;
}

/* ============================================
   NAVIGATION
   ============================================ */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  padding: var(--space-md) 0;
  background: var(--bg-nav);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
  transition: var(--transition-base);
}

.navbar.scrolled {
  padding: var(--space-sm) 0;
  box-shadow: var(--shadow-md);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-xl);
}

.nav-logo {
  font-family: var(--font-display);
  font-size: 1.3rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.nav-logo span {
  color: var(--accent);
}

.nav-links {
  display: flex;
  gap: var(--space-xl);
  align-items: center;
}

.nav-links a {
  font-family: var(--font-display);
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: color var(--transition-fast);
  position: relative;
  letter-spacing: 0.02em;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent);
  transition: width var(--transition-base);
}

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

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

/* Language Toggle */
.lang-toggle {
  display: flex;
  background: rgba(15, 23, 42, 0.6);
  border: 1px solid var(--border);
  border-radius: var(--radius-full);
  overflow: hidden;
  cursor: pointer;
}

.lang-toggle button {
  padding: 6px 14px;
  font-family: var(--font-display);
  font-size: 0.75rem;
  font-weight: 600;
  border: none;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  transition: var(--transition-fast);
  letter-spacing: 0.05em;
}

.lang-toggle button.active {
  background: var(--accent);
  color: white;
}

/* Mobile Menu */
.nav-hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  background: none;
  border: none;
  padding: 4px;
}

.nav-hamburger span {
  width: 22px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: var(--transition-fast);
}

.nav-hamburger.open span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-hamburger.open span:nth-child(2) {
  opacity: 0;
}

.nav-hamburger.open span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ============================================
   HERO SECTION
   ============================================ */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  position: relative;
  overflow: hidden;
  padding-top: 80px;
}

/* Animated grid background */
.hero-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(14, 165, 233, 0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(14, 165, 233, 0.03) 1px, transparent 1px);
  background-size: 60px 60px;
  mask-image: radial-gradient(ellipse 80% 60% at 50% 40%, black 40%, transparent 100%);
  -webkit-mask-image: radial-gradient(ellipse 80% 60% at 50% 40%, black 40%, transparent 100%);
}

/* Floating gradient orbs */
.hero-orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  opacity: 0.4;
  animation: orbFloat 20s ease-in-out infinite;
}

.hero-orb--1 {
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(14, 165, 233, 0.2), transparent);
  top: -10%;
  right: -5%;
  animation-delay: 0s;
}

.hero-orb--2 {
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(139, 92, 246, 0.15), transparent);
  bottom: -10%;
  left: -5%;
  animation-delay: -7s;
}

.hero-orb--3 {
  width: 300px;
  height: 300px;
  background: radial-gradient(circle, rgba(14, 165, 233, 0.1), transparent);
  top: 50%;
  left: 40%;
  animation-delay: -14s;
}

@keyframes orbFloat {

  0%,
  100% {
    transform: translate(0, 0) scale(1);
  }

  33% {
    transform: translate(30px, -40px) scale(1.05);
  }

  66% {
    transform: translate(-20px, 20px) scale(0.95);
  }
}

.hero-content {
  position: relative;
  z-index: 2;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-4xl);
  align-items: center;
  width: 100%;
}

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

.hero-greeting {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 400;
  color: var(--accent);
  margin-bottom: var(--space-md);
  letter-spacing: 0.05em;
}

.hero-name {
  font-size: clamp(2.5rem, 6vw, 4rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  margin-bottom: var(--space-md);
  line-height: 1.1;
}

.hero-roles {
  font-size: clamp(1.1rem, 2.5vw, 1.4rem);
  font-weight: 400;
  color: var(--text-secondary);
  margin-bottom: var(--space-lg);
  min-height: 2rem;
}

.typing-cursor {
  display: inline-block;
  width: 3px;
  height: 1.2em;
  background: var(--accent);
  margin-left: 2px;
  vertical-align: text-bottom;
  animation: blink 1s step-end infinite;
}

@keyframes blink {

  0%,
  100% {
    opacity: 1;
  }

  50% {
    opacity: 0;
  }
}

.hero-description {
  font-size: 1.05rem;
  color: var(--text-secondary);
  margin-bottom: var(--space-2xl);
  line-height: 1.8;
}

.hero-cta {
  display: flex;
  gap: var(--space-md);
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 14px 32px;
  font-family: var(--font-display);
  font-size: 0.9rem;
  font-weight: 600;
  border: none;
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: var(--transition-base);
  letter-spacing: 0.02em;
}

.btn-primary {
  background: var(--accent-gradient);
  color: white;
  box-shadow: 0 4px 20px var(--accent-glow);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px var(--accent-glow);
}

.btn-outline {
  background: transparent;
  color: var(--text-primary);
  border: 1px solid var(--border-active);
}

.btn-outline:hover {
  background: rgba(14, 165, 233, 0.1);
  border-color: var(--accent);
  transform: translateY(-2px);
}

/* Hero Image */
.hero-image-wrapper {
  display: flex;
  justify-content: center;
  align-items: center;
}

.hero-avatar-container {
  position: relative;
  width: 380px;
  height: 380px;
}

.hero-avatar-ring {
  position: absolute;
  inset: -8px;
  border-radius: 50%;
  border: 2px solid transparent;
  background: var(--accent-gradient) border-box;
  -webkit-mask:
    linear-gradient(#fff 0 0) padding-box,
    linear-gradient(#fff 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
  animation: spinRing 12s linear infinite;
}

.hero-avatar-ring::after {
  content: '';
  position: absolute;
  inset: -2px;
  border-radius: 50%;
  background: var(--accent-gradient);
  filter: blur(15px);
  opacity: 0.3;
  z-index: -1;
}

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

.hero-avatar {
  width: 100%;
  height: 100%;
  border-radius: 50%;
  object-fit: cover;
  position: relative;
  z-index: 1;
  border: 4px solid var(--bg-primary);
}

/* Floating badges */
.hero-badge {
  position: absolute;
  background: var(--bg-card);
  backdrop-filter: blur(15px);
  -webkit-backdrop-filter: blur(15px);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 10px 16px;
  font-family: var(--font-display);
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  z-index: 3;
  animation: badgeFloat 6s ease-in-out infinite;
  white-space: nowrap;
}

.hero-badge svg {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
}

.hero-badge--1 {
  top: 15%;
  right: -15%;
  animation-delay: 0s;
}

.hero-badge--2 {
  bottom: 20%;
  left: -10%;
  animation-delay: -2s;
}

.hero-badge--3 {
  bottom: 5%;
  right: -5%;
  animation-delay: -4s;
}

@keyframes badgeFloat {

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

  50% {
    transform: translateY(-10px);
  }
}

/* Scroll indicator */
.scroll-indicator {
  position: absolute;
  bottom: 40px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-sm);
  color: var(--text-muted);
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  font-family: var(--font-display);
}

.scroll-indicator-line {
  width: 1px;
  height: 40px;
  background: linear-gradient(to bottom, var(--accent), transparent);
  animation: scrollPulse 2s ease-in-out infinite;
}

@keyframes scrollPulse {

  0%,
  100% {
    opacity: 0.3;
    transform: scaleY(0.6);
  }

  50% {
    opacity: 1;
    transform: scaleY(1);
  }
}

/* ============================================
   ABOUT SECTION
   ============================================ */
.about {
  padding: var(--space-5xl) 0;
  position: relative;
}

.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-4xl);
  align-items: start;
}

.about-text p {
  color: var(--text-secondary);
  font-size: 1.05rem;
  margin-bottom: var(--space-lg);
}

.about-text p strong {
  color: var(--text-primary);
  font-weight: 600;
}

.stats-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-lg);
}

.stat-card {
  background: var(--bg-card);
  backdrop-filter: blur(15px);
  -webkit-backdrop-filter: blur(15px);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  text-align: center;
  transition: var(--transition-base);
  position: relative;
  overflow: hidden;
}

.stat-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--accent-gradient);
  transform: scaleX(0);
  transition: transform var(--transition-base);
}

.stat-card:hover {
  border-color: var(--border-active);
  transform: translateY(-4px);
  background: var(--bg-card-hover);
}

.stat-card:hover::before {
  transform: scaleX(1);
}

.stat-number {
  font-family: var(--font-display);
  font-size: 2.5rem;
  font-weight: 700;
  background: var(--accent-gradient-text);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1;
  margin-bottom: var(--space-sm);
}

.stat-label {
  font-size: 0.85rem;
  color: var(--text-secondary);
  font-weight: 500;
}

/* ============================================
   SKILLS SECTION
   ============================================ */
.skills {
  padding: var(--space-5xl) 0;
  position: relative;
}

.skills-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-xl);
}

.skill-card {
  background: var(--bg-card);
  backdrop-filter: blur(15px);
  -webkit-backdrop-filter: blur(15px);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--space-2xl);
  transition: var(--transition-base);
  position: relative;
  overflow: hidden;
}

.skill-card::after {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at var(--mouse-x, 50%) var(--mouse-y, 50%), rgba(14, 165, 233, 0.06) 0%, transparent 60%);
  pointer-events: none;
}

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

.skill-card-icon {
  width: 48px;
  height: 48px;
  background: rgba(14, 165, 233, 0.1);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--space-lg);
  color: var(--accent);
}

.skill-card-icon svg {
  width: 24px;
  height: 24px;
}

.skill-card h3 {
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: var(--space-md);
}

.skill-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-bottom: var(--space-lg);
}

.skill-tag {
  padding: 4px 12px;
  background: rgba(14, 165, 233, 0.08);
  border: 1px solid rgba(14, 165, 233, 0.15);
  border-radius: var(--radius-full);
  font-size: 0.78rem;
  color: var(--accent-light);
  font-weight: 500;
}

.skill-bar-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.skill-bar-item {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.skill-bar-label {
  display: flex;
  justify-content: space-between;
  font-size: 0.82rem;
  color: var(--text-secondary);
}

.skill-bar {
  width: 100%;
  height: 4px;
  background: rgba(148, 163, 184, 0.1);
  border-radius: var(--radius-full);
  overflow: hidden;
}

.skill-bar-fill {
  height: 100%;
  background: var(--accent-gradient);
  border-radius: var(--radius-full);
  width: 0;
  transition: width 1.2s var(--ease-out);
}

.skill-bar-fill.animated {
  /* width set by data-width attribute in JS */
}

/* ============================================
   EXPERIENCE SECTION
   ============================================ */
.experience {
  padding: var(--space-5xl) 0;
  position: relative;
}

.timeline {
  position: relative;
  max-width: 900px;
  margin: 0 auto;
}

.timeline::before {
  content: '';
  position: absolute;
  top: 0;
  bottom: 0;
  left: 28px;
  width: 2px;
  background: linear-gradient(to bottom, var(--accent), var(--accent-purple), transparent);
}

.timeline-item {
  position: relative;
  padding-left: 72px;
  padding-bottom: var(--space-3xl);
}

.timeline-item:last-child {
  padding-bottom: 0;
}

.timeline-dot {
  position: absolute;
  left: 18px;
  top: 4px;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--bg-primary);
  border: 3px solid var(--accent);
  z-index: 2;
  box-shadow: 0 0 12px var(--accent-glow);
}

.timeline-date {
  font-family: var(--font-display);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: var(--space-sm);
  letter-spacing: 0.05em;
}

.timeline-card {
  background: var(--bg-card);
  backdrop-filter: blur(15px);
  -webkit-backdrop-filter: blur(15px);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--space-2xl);
  transition: var(--transition-base);
}

.timeline-card:hover {
  border-color: var(--border-active);
  transform: translateX(4px);
}

.timeline-card h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: var(--space-xs);
}

.timeline-company {
  font-size: 0.9rem;
  color: var(--accent);
  font-weight: 500;
  margin-bottom: var(--space-sm);
}

.timeline-field {
  font-size: 0.85rem;
  color: var(--text-muted);
  font-style: italic;
  margin-bottom: var(--space-lg);
}

.timeline-card ul {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.timeline-card li {
  font-size: 0.92rem;
  color: var(--text-secondary);
  padding-left: var(--space-lg);
  position: relative;
  line-height: 1.6;
}

.timeline-card li::before {
  content: '▸';
  position: absolute;
  left: 0;
  color: var(--accent);
  font-weight: 700;
}

/* ============================================
   CERTIFICATIONS SECTION
   ============================================ */
.certifications {
  padding: var(--space-5xl) 0;
  position: relative;
}

.cert-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--space-lg);
}

.cert-card {
  position: relative;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  cursor: pointer;
  transition: var(--transition-base);
  group: cert;
}

.cert-card:hover {
  border-color: var(--border-active);
  transform: translateY(-4px);
  box-shadow: var(--shadow-glow);
}

.cert-card-img {
  width: 100%;
  height: 200px;
  object-fit: cover;
  transition: transform var(--transition-slow);
}

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

.cert-card-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(to top, rgba(5, 5, 8, 0.9) 0%, transparent 60%);
  display: flex;
  align-items: flex-end;
  padding: var(--space-lg);
  opacity: 0;
  transition: opacity var(--transition-base);
}

.cert-card:hover .cert-card-overlay {
  opacity: 1;
}

.cert-card-title {
  font-family: var(--font-display);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-primary);
}

.cert-card-issuer {
  font-size: 0.75rem;
  color: var(--accent);
  margin-top: 4px;
}

/* Lightbox */
.lightbox {
  position: fixed;
  inset: 0;
  z-index: 10000;
  background: rgba(0, 0, 0, 0.92);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-xl);
  opacity: 0;
  visibility: hidden;
  transition: var(--transition-base);
}

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

.lightbox img {
  max-width: 90vw;
  max-height: 85vh;
  object-fit: contain;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  transform: scale(0.9);
  transition: transform var(--transition-base);
}

.lightbox.active img {
  transform: scale(1);
}

.lightbox-close {
  position: absolute;
  top: 20px;
  right: 24px;
  width: 44px;
  height: 44px;
  border: 1px solid var(--border);
  background: var(--bg-card);
  color: var(--text-primary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 1.2rem;
  transition: var(--transition-fast);
}

.lightbox-close:hover {
  background: rgba(239, 68, 68, 0.2);
  border-color: rgba(239, 68, 68, 0.5);
}

/* Lightbox nav arrows */
.lightbox-nav {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 48px;
  height: 48px;
  border: 1px solid var(--border);
  background: var(--bg-card);
  backdrop-filter: blur(15px);
  color: var(--text-primary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 1.2rem;
  transition: var(--transition-fast);
}

.lightbox-nav:hover {
  background: var(--bg-card-hover);
  border-color: var(--accent);
}

.lightbox-prev {
  left: 20px;
}

.lightbox-next {
  right: 20px;
}

/* ============================================
   CONTACT SECTION
   ============================================ */
.contact {
  padding: var(--space-5xl) 0;
  position: relative;
}

.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-4xl);
}

.contact-info-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
  margin-top: var(--space-xl);
}

.contact-info-item {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  padding: var(--space-lg);
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  transition: var(--transition-base);
}

.contact-info-item:hover {
  border-color: var(--border-active);
  transform: translateX(4px);
}

.contact-info-icon {
  width: 44px;
  height: 44px;
  min-width: 44px;
  background: rgba(14, 165, 233, 0.1);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent);
}

.contact-info-icon svg {
  width: 20px;
  height: 20px;
}

.contact-info-label {
  font-size: 0.78rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 2px;
}

.contact-info-value {
  font-size: 0.95rem;
  color: var(--text-primary);
  font-weight: 500;
}

/* Contact Form */
.contact-form {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.form-group label {
  font-family: var(--font-display);
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-secondary);
}

.form-group input,
.form-group textarea {
  padding: 14px 18px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 0.95rem;
  transition: var(--transition-fast);
  outline: none;
}

.form-group input:focus,
.form-group textarea:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

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

.form-group input::placeholder,
.form-group textarea::placeholder {
  color: var(--text-muted);
}

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

/* ============================================
   FOOTER
   ============================================ */
.footer {
  padding: var(--space-2xl) 0;
  border-top: 1px solid var(--border);
  text-align: center;
}

.footer-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-md);
}

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

.footer-text a {
  color: var(--accent);
  font-weight: 500;
}

.footer-social {
  display: flex;
  gap: var(--space-md);
}

.social-link {
  width: 40px;
  height: 40px;
  border: 1px solid var(--border);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  transition: var(--transition-fast);
}

.social-link:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: rgba(14, 165, 233, 0.1);
  transform: translateY(-2px);
}

.social-link svg {
  width: 18px;
  height: 18px;
}

/* ============================================
   MOBILE RESPONSIVE
   ============================================ */
@media (max-width: 1024px) {
  .hero-content {
    grid-template-columns: 1fr;
    text-align: center;
    gap: var(--space-2xl);
  }

  .hero-text {
    max-width: 100%;
    order: 2;
  }

  .hero-image-wrapper {
    order: 1;
  }

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

  .hero-avatar-container {
    width: 280px;
    height: 280px;
  }

  .hero-badge {
    display: none;
  }

  .about-grid {
    grid-template-columns: 1fr;
    gap: var(--space-2xl);
  }

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

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

@media (max-width: 768px) {
  html {
    font-size: 15px;
  }

  .nav-links {
    position: fixed;
    top: 0;
    right: -100%;
    width: 280px;
    height: 100vh;
    background: var(--bg-secondary);
    border-left: 1px solid var(--border);
    flex-direction: column;
    padding: 80px var(--space-xl) var(--space-xl);
    gap: var(--space-lg);
    transition: right var(--transition-base);
    z-index: 998;
  }

  .nav-links.open {
    right: 0;
  }

  .nav-hamburger {
    display: flex;
    z-index: 999;
  }

  .container {
    padding: 0 var(--space-md);
  }

  .hero {
    min-height: auto;
    padding-top: 100px;
    padding-bottom: var(--space-3xl);
  }

  .hero-avatar-container {
    width: 200px;
    height: 200px;
  }

  .hero-name {
    font-size: 2rem;
  }

  .stats-grid {
    grid-template-columns: 1fr 1fr;
    gap: var(--space-md);
  }

  .stat-card {
    padding: var(--space-lg);
  }

  .stat-number {
    font-size: 1.8rem;
  }

  .timeline::before {
    left: 16px;
  }

  .timeline-item {
    padding-left: 48px;
  }

  .timeline-dot {
    left: 8px;
    width: 18px;
    height: 18px;
  }

  .cert-grid {
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: var(--space-md);
  }

  .cert-card-img {
    height: 160px;
  }

  .scroll-indicator {
    display: none;
  }

  .footer-content {
    flex-direction: column;
  }

  /* Lightbox mobile */
  .lightbox-nav {
    width: 36px;
    height: 36px;
  }

  .lightbox-prev {
    left: 8px;
  }

  .lightbox-next {
    right: 8px;
  }
}

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

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

/* --- Project Gallery inside Experience --- */
.project-gallery {
  margin-top: var(--space-lg);
  padding-top: var(--space-md);
  border-top: 1px dashed var(--border);
}

.gallery-title {
  font-size: 0.95rem;
  color: var(--text-primary);
  margin-bottom: var(--space-md);
  font-weight: 500;
}

.gallery-grid {
  display: grid;
  /* Dùng auto-fit để các khối tự chia đều chiều ngang */
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: var(--space-sm);
}

.gallery-item {
  border-radius: var(--radius-sm);
  overflow: hidden;
  border: 1px solid var(--border);
  cursor: pointer;
  /* Đặt tỷ lệ cố định 16:9 để tất cả ảnh trong lưới đều bằng nhau dù ảnh gốc hình chữ nhật hay vuông */
  aspect-ratio: 16 / 9;
  position: relative;
  background-color: var(--bg-secondary);
}

.gallery-item::after {
  content: '🔍';
  position: absolute;
  inset: 0;
  background: rgba(15, 23, 42, 0.6);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: opacity var(--transition-fast);
  font-size: 1.5rem;
}

.gallery-item:hover::after {
  opacity: 1;
}

.gallery-item img {
  width: 100%;
  height: 100%;
  /* object-fit: cover sẽ lấp đầy box 16:9 mà không làm méo ảnh (có thể cắt xén viền một chút, khi click Phóng to sẽ thấy full) */
  object-fit: cover;
  /* Tập trung hiển thị phần đầu/trung tâm của ảnh thống kê */
  object-position: center top; 
  transition: transform var(--transition-base);
}

.gallery-item:hover img {
  transform: scale(1.08);
}

/* --- Print styles --- */
@media print {

  .navbar,
  .scroll-indicator,
  .hero-grid,
  .hero-orb,
  .lightbox,
  .nav-hamburger {
    display: none !important;
  }

  body {
    background: white;
    color: black;
  }

  .section-title,
  h1,
  h2,
  h3 {
    color: black;
  }
}