:root {
  --bg-primary: #0a0a1a;
  --bg-secondary: #0f172a;
  --bg-card: rgba(30, 27, 75, 0.5);
  --bg-glass: rgba(255, 255, 255, 0.03);
  --border-glass: rgba(255, 255, 255, 0.08);
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --accent-gold: #fbbf24;
  --accent-blue: #3b82f6;
  --accent-violet: #8b5cf6;
  --gradient-primary: linear-gradient(135deg, #3b82f6, #8b5cf6);
  --gradient-gold: linear-gradient(135deg, #fbbf24, #f59e0b);
  --glow-gold: 0 0 20px rgba(251, 191, 36, 0.3);
  --glow-blue: 0 0 20px rgba(59, 130, 246, 0.3);
  --glow-violet: 0 0 20px rgba(139, 92, 246, 0.3);
  --nav-height: 70px;
  --section-padding: 100px 0;
  --container-width: 1200px;
  --radius: 16px;
  --radius-sm: 10px;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

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

body {
  font-family: 'Tajawal', sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  direction: rtl;
  line-height: 1.7;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

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

ul { list-style: none; }

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

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

/* ===== SCROLLBAR ===== */
::-webkit-scrollbar { width: 8px; }
::-webkit-scrollbar-track { background: var(--bg-primary); }
::-webkit-scrollbar-thumb {
  background: linear-gradient(var(--accent-blue), var(--accent-violet));
  border-radius: 4px;
}

/* ===== NAVIGATION ===== */
.navbar {
  position: fixed;
  top: 0;
  right: 0;
  left: 0;
  height: var(--nav-height);
  z-index: 1000;
  background: rgba(10, 10, 26, 0.8);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-glass);
  transition: var(--transition);
}

.navbar.scrolled {
  background: rgba(10, 10, 26, 0.95);
  box-shadow: 0 4px 30px rgba(0, 0, 0, 0.3);
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.nav-logo {
  font-size: 1.5rem;
  font-weight: 800;
  background: var(--gradient-gold);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: -0.5px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav-links a {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: var(--transition);
  position: relative;
  padding: 4px 0;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  right: 0;
  width: 0;
  height: 2px;
  background: var(--gradient-primary);
  transition: var(--transition);
  border-radius: 2px;
}

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

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

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 4px;
  z-index: 1001;
}

.nav-toggle span {
  width: 24px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: var(--transition);
}

.nav-toggle.open span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

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

.nav-toggle.open span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* ===== HERO ===== */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
  padding-top: var(--nav-height);
}

.hero-bg {
  position: absolute;
  inset: 0;
  z-index: 0;
}

#particles-canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.hero-gradient-orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  opacity: 0.15;
  animation: orbFloat 8s ease-in-out infinite;
}

.hero-gradient-orb.orb-1 {
  width: 500px;
  height: 500px;
  background: var(--accent-blue);
  top: -100px;
  right: -100px;
  animation-delay: 0s;
}

.hero-gradient-orb.orb-2 {
  width: 400px;
  height: 400px;
  background: var(--accent-violet);
  bottom: -50px;
  left: -50px;
  animation-delay: -3s;
}

.hero-gradient-orb.orb-3 {
  width: 300px;
  height: 300px;
  background: var(--accent-gold);
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  animation-delay: -5s;
  opacity: 0.08;
}

@keyframes orbFloat {
  0%, 100% { transform: translate(0, 0) scale(1); }
  33% { transform: translate(30px, -30px) scale(1.05); }
  66% { transform: translate(-20px, 20px) scale(0.95); }
}

.hero-content {
  position: relative;
  z-index: 2;
  text-align: center;
  max-width: 800px;
  padding: 0 24px;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 20px;
  border-radius: 50px;
  background: var(--bg-glass);
  border: 1px solid var(--border-glass);
  font-size: 0.85rem;
  color: var(--accent-gold);
  margin-bottom: 24px;
  backdrop-filter: blur(10px);
}

.hero-badge i {
  font-size: 0.75rem;
}

.hero-name {
  font-size: clamp(2.8rem, 7vw, 5rem);
  font-weight: 900;
  line-height: 1.2;
  margin-bottom: 16px;
  background: linear-gradient(135deg, #f1f5f9 0%, #fbbf24 50%, #f1f5f9 100%);
  background-size: 200% auto;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  animation: shimmer 4s ease-in-out infinite;
}

@keyframes shimmer {
  0%, 100% { background-position: 0% center; }
  50% { background-position: 200% center; }
}

.hero-title {
  font-size: clamp(1.2rem, 3vw, 1.6rem);
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: 12px;
}

.hero-title span {
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  font-weight: 700;
}

.hero-tagline {
  font-size: clamp(1rem, 2vw, 1.15rem);
  color: var(--text-secondary);
  margin-bottom: 40px;
  opacity: 0.8;
}

.hero-ctas {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 32px;
  border-radius: 12px;
  font-family: 'Tajawal', sans-serif;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  border: none;
  position: relative;
  overflow: hidden;
}

.btn-primary {
  background: var(--gradient-primary);
  color: #fff;
  box-shadow: var(--glow-blue);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 0 40px rgba(59, 130, 246, 0.4);
}

.btn-secondary {
  background: var(--bg-glass);
  color: var(--text-primary);
  border: 1px solid var(--border-glass);
  backdrop-filter: blur(10px);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.08);
  transform: translateY(-2px);
  border-color: rgba(255, 255, 255, 0.15);
}

.btn-gold {
  background: var(--gradient-gold);
  color: #0a0a1a;
  box-shadow: var(--glow-gold);
}

.btn-gold:hover {
  transform: translateY(-2px);
  box-shadow: 0 0 40px rgba(251, 191, 36, 0.4);
}

.hero-tech-icons {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 24px;
  margin-top: 48px;
  opacity: 0.4;
}

.hero-tech-icons i {
  font-size: 1.4rem;
  color: var(--text-secondary);
  transition: var(--transition);
}

.hero-tech-icons i:hover {
  color: var(--accent-gold);
  opacity: 1;
}

/* ===== SECTION COMMON ===== */
.section {
  padding: var(--section-padding);
  position: relative;
}

.section-header {
  text-align: center;
  margin-bottom: 64px;
}

.section-label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent-blue);
  text-transform: uppercase;
  letter-spacing: 2px;
  margin-bottom: 12px;
}

.section-label i {
  font-size: 0.7rem;
}

.section-title {
  font-size: clamp(2rem, 4vw, 2.8rem);
  font-weight: 800;
  line-height: 1.3;
  margin-bottom: 16px;
}

.section-title .gradient-text {
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.section-subtitle {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto;
}

.section-divider {
  width: 60px;
  height: 3px;
  background: var(--gradient-primary);
  border-radius: 3px;
  margin: 16px auto 0;
}

/* ===== ABOUT ===== */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}

.about-image-wrapper {
  position: relative;
  display: flex;
  justify-content: center;
}

.about-avatar {
  width: 280px;
  height: 280px;
  border-radius: 50%;
  background: var(--gradient-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  box-shadow: var(--glow-blue);
}

.about-avatar::before {
  content: '';
  position: absolute;
  inset: -4px;
  border-radius: 50%;
  background: var(--gradient-primary);
  z-index: -1;
  opacity: 0.5;
  filter: blur(15px);
}

.about-avatar i {
  font-size: 6rem;
  color: rgba(255, 255, 255, 0.9);
}

.about-avatar-ring {
  position: absolute;
  inset: -20px;
  border-radius: 50%;
  border: 1px dashed rgba(139, 92, 246, 0.3);
  animation: spin 20s linear infinite;
}

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

.about-text h3 {
  font-size: 1.6rem;
  font-weight: 700;
  margin-bottom: 16px;
}

.about-text p {
  color: var(--text-secondary);
  font-size: 1.05rem;
  line-height: 1.9;
  margin-bottom: 32px;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

.stat-card {
  background: var(--bg-glass);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-sm);
  padding: 20px;
  text-align: center;
  backdrop-filter: blur(10px);
  transition: var(--transition);
}

.stat-card:hover {
  border-color: rgba(139, 92, 246, 0.3);
  transform: translateY(-2px);
  box-shadow: var(--glow-violet);
}

.stat-number {
  font-size: 2rem;
  font-weight: 800;
  background: var(--gradient-gold);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  display: block;
}

.stat-label {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-top: 4px;
}

/* ===== EXPERTISE ===== */
.expertise-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.expertise-card {
  background: var(--bg-glass);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius);
  padding: 32px 24px;
  backdrop-filter: blur(10px);
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.expertise-card::before {
  content: '';
  position: absolute;
  top: 0;
  right: 0;
  left: 0;
  height: 3px;
  background: var(--gradient-primary);
  opacity: 0;
  transition: var(--transition);
}

.expertise-card:hover {
  transform: translateY(-4px);
  border-color: rgba(139, 92, 246, 0.3);
  box-shadow: 0 8px 40px rgba(0, 0, 0, 0.3);
}

.expertise-card:hover::before {
  opacity: 1;
}

.expertise-icon {
  width: 56px;
  height: 56px;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 20px;
  background: rgba(59, 130, 246, 0.1);
  color: var(--accent-blue);
}

.expertise-card:nth-child(2) .expertise-icon {
  background: rgba(139, 92, 246, 0.1);
  color: var(--accent-violet);
}

.expertise-card:nth-child(3) .expertise-icon {
  background: rgba(251, 191, 36, 0.1);
  color: var(--accent-gold);
}

.expertise-card:nth-child(4) .expertise-icon {
  background: rgba(16, 185, 129, 0.1);
  color: #10b981;
}

.expertise-card:nth-child(5) .expertise-icon {
  background: rgba(236, 72, 153, 0.1);
  color: #ec4899;
}

.expertise-card:nth-child(6) .expertise-icon {
  background: rgba(14, 165, 233, 0.1);
  color: #0ea5e9;
}

.expertise-card h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.expertise-card p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ===== PROJECTS ===== */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.project-card {
  background: var(--bg-glass);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius);
  padding: 32px;
  backdrop-filter: blur(10px);
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.project-card.featured {
  grid-column: 1 / -1;
  background: linear-gradient(135deg, rgba(59, 130, 246, 0.08), rgba(139, 92, 246, 0.08));
  border-color: rgba(139, 92, 246, 0.2);
}

.project-card:hover {
  transform: translateY(-4px);
  border-color: rgba(59, 130, 246, 0.3);
  box-shadow: 0 8px 40px rgba(0, 0, 0, 0.3);
}

.project-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  margin-bottom: 16px;
}

.project-icon {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
  background: var(--gradient-primary);
  color: #fff;
}

.project-card:nth-child(2) .project-icon {
  background: var(--gradient-gold);
  color: #0a0a1a;
}

.project-card:nth-child(3) .project-icon {
  background: linear-gradient(135deg, #10b981, #059669);
}

.project-card:nth-child(4) .project-icon {
  background: linear-gradient(135deg, #ec4899, #d946ef);
}

.project-card:nth-child(5) .project-icon {
  background: linear-gradient(135deg, #0ea5e9, #06b6d4);
}

.project-link {
  font-size: 0.85rem;
  color: var(--accent-blue);
  display: flex;
  align-items: center;
  gap: 4px;
  transition: var(--transition);
}

.project-link:hover {
  color: var(--accent-gold);
}

.project-card h3 {
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.project-card p {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 16px;
}

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

.project-tag {
  padding: 4px 12px;
  border-radius: 50px;
  font-size: 0.75rem;
  font-weight: 500;
  background: rgba(59, 130, 246, 0.1);
  color: var(--accent-blue);
  border: 1px solid rgba(59, 130, 246, 0.15);
}

/* ===== AI UNIVERSITY ===== */
.university-section {
  background: linear-gradient(180deg, var(--bg-primary) 0%, rgba(30, 27, 75, 0.3) 50%, var(--bg-primary) 100%);
  position: relative;
  overflow: hidden;
}

.university-section::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 20% 50%, rgba(59, 130, 246, 0.06) 0%, transparent 50%),
    radial-gradient(circle at 80% 50%, rgba(139, 92, 246, 0.06) 0%, transparent 50%);
}

.university-section .container {
  position: relative;
  z-index: 2;
}

.uni-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 24px;
  border-radius: 50px;
  background: linear-gradient(135deg, rgba(251, 191, 36, 0.15), rgba(245, 158, 11, 0.1));
  border: 1px solid rgba(251, 191, 36, 0.2);
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--accent-gold);
  margin-bottom: 20px;
}

.uni-title {
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  font-weight: 900;
  line-height: 1.3;
  margin-bottom: 20px;
  background: linear-gradient(135deg, var(--accent-gold), #f59e0b, var(--accent-gold));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.uni-description {
  font-size: 1.1rem;
  color: var(--text-secondary);
  line-height: 1.9;
  max-width: 750px;
  margin: 0 auto 48px;
}

.uni-features {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  margin-bottom: 48px;
}

.uni-feature {
  background: var(--bg-glass);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius);
  padding: 28px 20px;
  text-align: center;
  backdrop-filter: blur(10px);
  transition: var(--transition);
}

.uni-feature:hover {
  transform: translateY(-4px);
  border-color: rgba(251, 191, 36, 0.3);
  box-shadow: var(--glow-gold);
}

.uni-feature-icon {
  font-size: 2rem;
  margin-bottom: 12px;
  display: block;
}

.uni-feature h4 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 6px;
  color: var(--accent-gold);
}

.uni-feature p {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.uni-stats {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 48px;
  margin-bottom: 40px;
  flex-wrap: wrap;
}

.uni-stat {
  text-align: center;
}

.uni-stat-number {
  font-size: 1.8rem;
  font-weight: 800;
  color: var(--text-primary);
  display: block;
}

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

.uni-cta {
  text-align: center;
}

.btn-uni {
  padding: 18px 48px;
  font-size: 1.1rem;
  border-radius: 14px;
  animation: pulse-glow 2s ease-in-out infinite;
}

@keyframes pulse-glow {
  0%, 100% { box-shadow: 0 0 20px rgba(251, 191, 36, 0.3); }
  50% { box-shadow: 0 0 40px rgba(251, 191, 36, 0.5); }
}

/* ===== EXPERIENCE TIMELINE ===== */
.timeline {
  position: relative;
  max-width: 700px;
  margin: 0 auto;
}

.timeline::before {
  content: '';
  position: absolute;
  top: 0;
  left: auto;
  right: 20px;
  transform: none;
  width: 2px;
  height: 100%;
  background: linear-gradient(to bottom, var(--accent-blue), var(--accent-violet), transparent);
}

.timeline-item {
  position: relative;
  padding: 0 55px 40px 0;
  width: 100%;
}

.timeline-dot {
  position: absolute;
  top: 4px;
  right: 13px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--gradient-primary);
  box-shadow: var(--glow-blue);
  z-index: 2;
}

.timeline-date {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--accent-blue);
  margin-bottom: 4px;
}

.timeline-item h4 {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 4px;
}

.timeline-item p {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

/* ===== SKILLS TAGS ===== */
.skills-tags {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
  max-width: 800px;
  margin: 0 auto;
}

.skill-tag {
  padding: 10px 24px;
  border-radius: 50px;
  font-size: 0.9rem;
  font-weight: 500;
  background: var(--bg-glass);
  border: 1px solid var(--border-glass);
  color: var(--text-secondary);
  transition: var(--transition);
  cursor: default;
}

.skill-tag:hover {
  color: var(--text-primary);
  border-color: var(--accent-blue);
  background: rgba(59, 130, 246, 0.1);
  transform: translateY(-2px);
}

.skill-tag.highlight {
  border-color: rgba(251, 191, 36, 0.3);
  color: var(--accent-gold);
}

.skill-tag.highlight:hover {
  background: rgba(251, 191, 36, 0.1);
  border-color: var(--accent-gold);
}

/* ===== CONTACT ===== */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  max-width: 800px;
  margin: 0 auto;
}

.contact-card {
  background: var(--bg-glass);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius);
  padding: 32px 24px;
  text-align: center;
  backdrop-filter: blur(10px);
  transition: var(--transition);
}

.contact-card:hover {
  transform: translateY(-4px);
  border-color: rgba(59, 130, 246, 0.3);
  box-shadow: var(--glow-blue);
}

.contact-card-icon {
  width: 56px;
  height: 56px;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
  margin: 0 auto 16px;
  background: rgba(59, 130, 246, 0.1);
  color: var(--accent-blue);
}

.contact-card:nth-child(2) .contact-card-icon {
  background: rgba(139, 92, 246, 0.1);
  color: var(--accent-violet);
}

.contact-card:nth-child(3) .contact-card-icon {
  background: rgba(251, 191, 36, 0.1);
  color: var(--accent-gold);
}

.contact-card h4 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 6px;
}

.contact-card p {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.contact-card a {
  color: var(--accent-blue);
  transition: var(--transition);
}

.contact-card a:hover {
  color: var(--accent-gold);
}

/* ===== FOOTER ===== */
.footer {
  padding: 40px 0;
  border-top: 1px solid var(--border-glass);
  text-align: center;
}

.footer-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
}

.footer-logo {
  font-size: 1.2rem;
  font-weight: 800;
  background: var(--gradient-gold);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

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

.footer-copy {
  font-size: 0.8rem;
  color: var(--text-secondary);
  opacity: 0.6;
}

.back-to-top {
  position: fixed;
  bottom: 30px;
  left: 30px;
  width: 44px;
  height: 44px;
  border-radius: 12px;
  background: var(--gradient-primary);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: var(--transition);
  border: none;
  box-shadow: var(--glow-blue);
  z-index: 999;
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  transform: translateY(-3px);
  box-shadow: 0 0 30px rgba(59, 130, 246, 0.4);
}

/* ===== ANIMATIONS ===== */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.7s cubic-bezier(0.4, 0, 0.2, 1), transform 0.7s cubic-bezier(0.4, 0, 0.2, 1);
}

.reveal.revealed {
  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; }

/* Accessibility: respect user motion preferences */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
  .reveal {
    opacity: 1;
    transform: none;
  }
  #particles-canvas {
    display: none;
  }
}

/* ===== RESPONSIVE ===== */
@media (max-width: 1024px) {
  .expertise-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .uni-features {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  :root {
    --section-padding: 70px 0;
  }

  .nav-links {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(10, 10, 26, 0.98);
    backdrop-filter: blur(20px);
    flex-direction: column;
    justify-content: center;
    gap: 24px;
    transform: translateX(100%);
    transition: var(--transition);
    z-index: 999;
  }

  .nav-links.open {
    transform: translateX(0);
  }

  .nav-links a {
    font-size: 1.3rem;
  }

  .nav-toggle {
    display: flex;
  }

  .about-grid {
    grid-template-columns: 1fr;
    gap: 40px;
    text-align: center;
  }

  .about-avatar {
    width: 200px;
    height: 200px;
  }

  .about-avatar i {
    font-size: 4rem;
  }

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

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

  .project-card.featured {
    grid-column: auto;
  }

  .uni-features {
    grid-template-columns: 1fr 1fr;
  }

  .uni-stats {
    gap: 24px;
  }

  .timeline::before {
    right: 15px;
  }

  .timeline-item,
  .timeline-item:nth-child(odd),
  .timeline-item:nth-child(even) {
    width: 100%;
    margin: 0;
    padding: 0 45px 40px 0;
    text-align: right;
  }

  .timeline-item:nth-child(odd) .timeline-dot,
  .timeline-item:nth-child(even) .timeline-dot {
    right: 8px;
    left: auto;
  }

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

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

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

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

  .uni-features {
    grid-template-columns: 1fr;
  }

  .uni-stats {
    flex-direction: column;
    gap: 16px;
  }

  .hero-tech-icons {
    gap: 16px;
  }
}