/* =====================================================
   PORTFOLIO WEBSITE - ANCHIT GUPTA
   Modern Dark Theme with Gradient Accents
   ===================================================== */

/* --- Design Tokens --- */
:root {
  --bg-primary: #0f0f23;
  --bg-secondary: #1a1a2e;
  --bg-card: rgba(26, 26, 46, 0.8);
  --accent-primary: #667eea;
  --accent-secondary: #764ba2;
  --accent-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  --text-primary: #ffffff;
  --text-secondary: #8892b0;
  --text-accent: #64ffda;
  --border-color: rgba(255, 255, 255, 0.1);
  --shadow-lg: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 40px rgba(102, 126, 234, 0.3);
  --transition-fast: 0.2s ease;
  --transition-medium: 0.3s ease;
  --font-mono: 'SF Mono', 'Fira Code', 'Consolas', monospace;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

/* --- Light Theme Variables --- */
[data-theme="light"] {
  --bg-primary: #f8f9fc;
  --bg-secondary: #ffffff;
  --bg-card: rgba(255, 255, 255, 0.9);
  --accent-primary: #5a67d8;
  --accent-secondary: #6b46c1;
  --accent-gradient: linear-gradient(135deg, #5a67d8 0%, #6b46c1 100%);
  --text-primary: #1a202c;
  --text-secondary: #4a5568;
  --text-accent: #319795;
  --border-color: rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 25px 50px -12px rgba(0, 0, 0, 0.15);
  --shadow-glow: 0 0 40px rgba(90, 103, 216, 0.2);
}

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

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
}

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

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

/* --- Typography --- */
h1,
h2,
h3,
h4 {
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 1rem;
}

h1 {
  font-size: clamp(2.5rem, 8vw, 4.5rem);
}

h2 {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
}

h3 {
  font-size: 1.25rem;
}

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

.section-title {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 3rem;
}

.section-title::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--border-color);
  max-width: 300px;
}

.section-number {
  font-family: var(--font-mono);
  color: var(--text-accent);
  font-size: 1rem;
}

/* --- Layout --- */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}

section {
  padding: 6rem 0;
}

/* --- Navigation --- */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  padding: 1rem 2rem;
  background: rgba(15, 15, 35, 0.9);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-color);
  transition: all var(--transition-medium);
}

.navbar.scrolled {
  padding: 0.75rem 2rem;
  box-shadow: var(--shadow-lg);
}

.nav-content {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav-logo {
  font-size: 1.5rem;
  font-weight: 700;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.nav-links {
  display: flex;
  gap: 1rem;
  list-style: none;
}

.nav-links a {
  color: var(--text-secondary);
  font-size: 0.8rem;
  font-family: var(--font-mono);
  transition: color var(--transition-fast);
  white-space: nowrap;
}

.nav-links a:hover {
  color: var(--text-accent);
}

.nav-links .number {
  color: var(--text-accent);
  margin-right: 0.25rem;
}

/* --- Theme Toggle Button --- */
.theme-toggle {
  background: transparent;
  border: 1px solid var(--border-color);
  border-radius: 50%;
  width: 42px;
  height: 42px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  color: var(--text-secondary);
  font-size: 1.1rem;
  transition: all var(--transition-medium);
  margin-right: 1rem;
}

.theme-toggle:hover {
  color: var(--text-accent);
  border-color: var(--text-accent);
  transform: rotate(15deg);
}

.theme-toggle i {
  transition: transform 0.5s ease;
}

[data-theme="light"] .theme-toggle i {
  transform: rotate(360deg);
}

/* --- Nav CTA Button --- */
.nav-cta {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.6rem 1.25rem;
  background: var(--accent-gradient);
  color: var(--text-primary) !important;
  border-radius: 6px;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 500;
  transition: all var(--transition-medium);
  border: none;
  text-decoration: none;
  margin-right: 0.5rem;
  white-space: nowrap;
}

.nav-cta:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-glow);
  color: var(--text-primary) !important;
}

.nav-cta i {
  font-size: 0.9rem;
}

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

.nav-toggle span {
  width: 25px;
  height: 2px;
  background: var(--text-primary);
  transition: all var(--transition-fast);
}

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

.hero-bg {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background:
    radial-gradient(ellipse at 20% 80%, rgba(102, 126, 234, 0.15) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 20%, rgba(118, 75, 162, 0.15) 0%, transparent 50%),
    radial-gradient(ellipse at 50% 50%, rgba(100, 255, 218, 0.05) 0%, transparent 50%);
  z-index: -1;
}

.hero-content {
  max-width: 800px;
}

.hero-greeting {
  font-family: var(--font-mono);
  color: var(--text-accent);
  font-size: 1rem;
  margin-bottom: 1.5rem;
  opacity: 0;
  animation: fadeInUp 0.6s ease forwards;
}

.hero-name {
  margin-bottom: 0.5rem;
  opacity: 0;
  animation: fadeInUp 0.6s ease 0.1s forwards;
}

.hero-title {
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
  opacity: 0;
  animation: fadeInUp 0.6s ease 0.2s forwards;
}

.hero-description {
  color: var(--text-secondary);
  max-width: 500px;
  margin-bottom: 2.5rem;
  font-size: 1.1rem;
  opacity: 0;
  animation: fadeInUp 0.6s ease 0.3s forwards;
}

.hero-cta {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  opacity: 0;
  animation: fadeInUp 0.6s ease 0.4s forwards;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 1rem 2rem;
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  cursor: pointer;
  transition: all var(--transition-medium);
  border: 1px solid transparent;
}

.btn-primary {
  background: var(--accent-gradient);
  color: var(--text-primary);
  border: none;
}

.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-glow);
  color: var(--text-primary);
}

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

.btn-outline:hover {
  background: rgba(100, 255, 218, 0.1);
  transform: translateY(-3px);
}

/* --- About Section --- */
.about-content {
  display: grid;
  grid-template-columns: 3fr 2fr;
  gap: 4rem;
  align-items: start;
}

.about-text p {
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
}

.about-text strong {
  color: var(--text-primary);
}

.skills-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.75rem;
  margin-top: 2rem;
}

.skill-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.skill-item::before {
  content: '▹';
  color: var(--text-accent);
}

.about-image {
  position: relative;
}

.about-image img {
  width: 100%;
  max-width: 300px;
  border-radius: 8px;
  filter: grayscale(20%);
  transition: all var(--transition-medium);
}

.about-image::before {
  content: '';
  position: absolute;
  top: 20px;
  left: 20px;
  right: -20px;
  bottom: -20px;
  border: 2px solid var(--text-accent);
  border-radius: 8px;
  z-index: -1;
  transition: all var(--transition-medium);
}

.about-image:hover img {
  filter: grayscale(0%);
  transform: translate(-5px, -5px);
}

.about-image:hover::before {
  transform: translate(5px, 5px);
}

/* --- Experience Section --- */
.experience-timeline {
  position: relative;
  max-width: 800px;
}

.experience-item {
  position: relative;
  padding-left: 2rem;
  padding-bottom: 3rem;
  border-left: 2px solid var(--border-color);
}

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

.experience-item::before {
  content: '';
  position: absolute;
  left: -8px;
  top: 0;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--accent-gradient);
  box-shadow: 0 0 20px rgba(102, 126, 234, 0.5);
}

.experience-date {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text-accent);
  margin-bottom: 0.5rem;
}

.experience-role {
  font-size: 1.25rem;
  margin-bottom: 0.25rem;
}

.experience-company {
  color: var(--text-accent);
  font-size: 1rem;
  margin-bottom: 1rem;
}

.experience-description {
  color: var(--text-secondary);
}

.experience-description li {
  margin-bottom: 0.5rem;
  position: relative;
  padding-left: 1.5rem;
}

.experience-description li::before {
  content: '▹';
  position: absolute;
  left: 0;
  color: var(--text-accent);
}

/* --- Education Section --- */
.education-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: 2rem;
}

.education-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 2rem;
  transition: all var(--transition-medium);
  backdrop-filter: blur(10px);
}

.education-card:hover {
  transform: translateY(-5px);
  border-color: var(--text-accent);
  box-shadow: var(--shadow-glow);
}

.education-degree {
  color: var(--text-accent);
  font-family: var(--font-mono);
  font-size: 0.9rem;
  margin-bottom: 0.75rem;
}

.education-institution {
  font-size: 1.25rem;
  margin-bottom: 0.5rem;
}

.education-period {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 1rem;
}

.education-details {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.education-highlight {
  display: inline-block;
  margin-top: 1rem;
  padding: 0.5rem 1rem;
  background: rgba(100, 255, 218, 0.1);
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text-accent);
}

/* --- Projects Section --- */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: 1.5rem;
}

.project-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 2rem;
  display: flex;
  flex-direction: column;
  transition: all var(--transition-medium);
  backdrop-filter: blur(10px);
}

.project-card:hover {
  transform: translateY(-5px);
  border-color: var(--accent-primary);
  box-shadow: var(--shadow-glow);
}

.project-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 1.5rem;
}

.project-icon {
  font-size: 2.5rem;
}

.project-links {
  display: flex;
  gap: 1rem;
}

.project-links a {
  color: var(--text-secondary);
  font-size: 1.25rem;
  transition: color var(--transition-fast);
}

.project-links a:hover {
  color: var(--text-accent);
}

.project-title {
  font-size: 1.25rem;
  margin-bottom: 0.75rem;
  transition: color var(--transition-fast);
}

.project-card:hover .project-title {
  color: var(--text-accent);
}

.project-description {
  color: var(--text-secondary);
  font-size: 0.95rem;
  flex-grow: 1;
  margin-bottom: 1.5rem;
}

.project-tech {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.project-tech span {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-secondary);
}

/* --- Publications Section --- */
.section-subtitle {
  color: var(--text-secondary);
  font-size: 1.1rem;
  margin-top: -2rem;
  margin-bottom: 2.5rem;
}

.publications-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: 1.5rem;
}

.publication-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 1.5rem;
  transition: all var(--transition-medium);
  backdrop-filter: blur(10px);
}

.publication-card:hover {
  transform: translateY(-5px);
  border-color: var(--accent-primary);
  box-shadow: var(--shadow-glow);
}

.publication-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
}

.publication-date {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text-accent);
}

.publication-platform {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.publication-platform i {
  margin-right: 0.25rem;
}

.publication-title {
  font-size: 1.15rem;
  margin-bottom: 0.75rem;
  line-height: 1.4;
}

.publication-title a {
  color: var(--text-primary);
  transition: color var(--transition-fast);
}

.publication-title a:hover {
  color: var(--text-accent);
}

.publication-excerpt {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 1rem;
  line-height: 1.5;
}

.publication-tags {
  display: flex;
  gap: 0.75rem;
}

.publication-tags span {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-accent);
  background: rgba(100, 255, 218, 0.1);
  padding: 0.25rem 0.75rem;
  border-radius: 4px;
}

.publications-cta {
  text-align: center;
  margin-top: 3rem;
}

/* --- Certifications Section --- */
.certifications-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
}

.cert-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 1.5rem;
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  transition: all var(--transition-medium);
  backdrop-filter: blur(10px);
}

.cert-card:hover {
  border-color: var(--text-accent);
  transform: translateX(5px);
}

.cert-icon {
  font-size: 1.5rem;
  flex-shrink: 0;
}

.cert-info h4 {
  font-size: 1rem;
  margin-bottom: 0.25rem;
}

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

.cert-highlight {
  background: var(--accent-gradient);
  position: relative;
}

.cert-highlight::before {
  content: '⭐';
  position: absolute;
  top: -10px;
  right: -10px;
  font-size: 1.25rem;
}

/* --- Contact Section --- */
.contact {
  text-align: center;
  padding: 8rem 0;
}

.contact-content {
  max-width: 600px;
  margin: 0 auto;
}

.contact-subtitle {
  font-family: var(--font-mono);
  color: var(--text-accent);
  margin-bottom: 1rem;
}

.contact-title {
  font-size: clamp(2rem, 5vw, 3rem);
  margin-bottom: 1.5rem;
}

.contact-description {
  color: var(--text-secondary);
  margin-bottom: 3rem;
}

.contact-cta {
  margin-bottom: 3rem;
}

.social-links {
  display: flex;
  justify-content: center;
  gap: 2rem;
  margin-top: 3rem;
}

.social-links a {
  color: var(--text-secondary);
  font-size: 1.5rem;
  transition: all var(--transition-medium);
}

.social-links a:hover {
  color: var(--text-accent);
  transform: translateY(-5px);
}

/* --- Footer --- */
.footer {
  padding: 2rem;
  text-align: center;
  border-top: 1px solid var(--border-color);
}

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

/* --- Animations --- */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: all 0.6s ease;
}

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

/* --- Responsive Design --- */
@media (max-width: 1200px) {
  .nav-links {
    gap: 0.75rem;
  }

  .nav-links a {
    font-size: 0.75rem;
  }
}

@media (max-width: 1024px) {
  .nav-links {
    display: none;
    position: fixed;
    top: 70px;
    left: 0;
    right: 0;
    background: var(--bg-secondary);
    flex-direction: column;
    padding: 2rem;
    gap: 1.5rem;
    border-bottom: 1px solid var(--border-color);
  }

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

  .nav-links a {
    font-size: 0.95rem;
  }

  .nav-toggle {
    display: flex;
  }

  .nav-cta {
    padding: 0.5rem 1rem;
    font-size: 0.8rem;
  }
}

@media (max-width: 992px) {
  .about-content {
    grid-template-columns: 1fr;
  }

  .about-image {
    max-width: 300px;
    margin: 0 auto;
  }
}

@media (max-width: 768px) {
  .nav-cta {
    padding: 0.6rem;
    font-size: 0;
    margin-right: 0.5rem;
  }

  .nav-cta i {
    font-size: 1rem;
  }

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

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

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

  section {
    padding: 4rem 0;
  }

  .container {
    padding: 0 1.25rem;
  }

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

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

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

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

/* --- Scrollbar --- */
::-webkit-scrollbar {
  width: 10px;
}

::-webkit-scrollbar-track {
  background: var(--bg-primary);
}

::-webkit-scrollbar-thumb {
  background: var(--bg-secondary);
  border-radius: 5px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--accent-primary);
}