/* ================================
   CSS Variables - Design System
   ================================ */

:root {
  /* Light Mode Colors */
  --color-primary: hsl(240, 100%, 60%);
  --color-primary-hover: hsl(240, 100%, 55%);
  --color-secondary: hsl(280, 100%, 65%);
  --color-background: hsl(0, 0%, 98%);
  --color-surface: hsl(0, 0%, 100%);
  --color-text: hsl(0, 0%, 15%);
  --color-text-secondary: hsl(0, 0%, 40%);
  --color-border: hsl(0, 0%, 90%);

  /* Gradients */
  --gradient-primary: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
  --gradient-background: linear-gradient(
    180deg,
    var(--color-background) 0%,
    hsl(240, 20%, 97%) 100%
  );

  /* Spacing */
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
  --spacing-2xl: 4rem;
  --spacing-3xl: 6rem;

  /* Typography */
  --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-heading: 'Outfit', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

  /* Shadows */
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.12);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.16);

  /* Transitions */
  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s ease;
  --transition-slow: 0.6s ease;

  /* Border Radius */
  --radius-sm: 0.5rem;
  --radius-md: 1rem;
  --radius-lg: 1.5rem;
  --radius-full: 9999px;

  /* Z-index */
  --z-nav: 100;
  --z-modal: 200;
}

/* Dark Mode Colors */
[data-theme='dark'] {
  --color-primary: hsl(240, 100%, 70%);
  --color-primary-hover: hsl(240, 100%, 75%);
  --color-secondary: hsl(280, 100%, 75%);
  --color-background: hsl(220, 20%, 10%);
  --color-surface: hsl(220, 18%, 15%);
  --color-text: hsl(0, 0%, 95%);
  --color-text-secondary: hsl(0, 0%, 70%);
  --color-border: hsl(220, 15%, 25%);

  --gradient-background: linear-gradient(
    180deg,
    var(--color-background) 0%,
    hsl(220, 20%, 12%) 100%
  );
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);
}

/* ================================
   Reset & Base Styles
   ================================ */

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-primary);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text);
  background: var(--gradient-background);
  transition:
    background var(--transition-normal),
    color var(--transition-normal);
  overflow-x: hidden;
}

/* ================================
   Typography
   ================================ */

h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: var(--font-heading);
  line-height: 1.2;
  font-weight: 700;
}

h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
}
h2 {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
}
h3 {
  font-size: clamp(1.25rem, 3vw, 1.75rem);
}

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

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

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

/* ================================
   Layout Components
   ================================ */

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

.section {
  padding: var(--spacing-3xl) 0;
}

.section-alt {
  background: var(--color-surface);
  backdrop-filter: blur(10px);
}

.section-title {
  text-align: center;
  margin-bottom: var(--spacing-2xl);
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ================================
   Navigation
   ================================ */

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background: rgba(255, 255, 255, 0.8);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-border);
  z-index: var(--z-nav);
  transition: all var(--transition-normal);
}

[data-theme='dark'] .nav {
  background: rgba(28, 32, 43, 0.8);
}

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

.nav-logo {
  font-family: var(--font-heading);
  font-size: 1.5rem;
  font-weight: 900;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.desktop-nav {
  display: none;
  list-style: none;
  gap: var(--spacing-lg);
}

.desktop-nav a {
  color: var(--color-text);
  font-weight: 500;
  position: relative;
  padding: var(--spacing-xs) 0;
}

.desktop-nav a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--gradient-primary);
  transition: width var(--transition-normal);
}

.desktop-nav a:hover::after {
  width: 100%;
}

@media (min-width: 768px) {
  .desktop-nav {
    display: flex;
  }
}

/* Theme Toggle */
.theme-toggle {
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--spacing-xs);
  display: flex;
  align-items: center;
  color: var(--color-text);
  transition: transform var(--transition-fast);
}

.theme-toggle:hover {
  transform: scale(1.1);
}

[data-theme='light'] .moon-icon {
  display: none;
}

[data-theme='dark'] .sun-icon {
  display: none;
}

/* Mobile Menu */
.mobile-menu-toggle {
  display: flex;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
}

.mobile-menu-toggle span {
  width: 25px;
  height: 3px;
  background: var(--color-text);
  border-radius: var(--radius-full);
  transition: all var(--transition-normal);
}

@media (min-width: 768px) {
  .mobile-menu-toggle {
    display: none;
  }
}

.mobile-menu {
  display: none;
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: var(--spacing-md);
}

.mobile-menu.active {
  display: block;
}

.mobile-menu ul {
  list-style: none;
}

.mobile-menu li {
  margin: var(--spacing-sm) 0;
}

.mobile-menu a {
  color: var(--color-text);
  font-weight: 500;
  padding: var(--spacing-sm);
  display: block;
}

/* ================================
   Hero Section
   ================================ */

.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding-top: 80px;
  overflow: hidden;
}

.hero-background {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--gradient-background);
  z-index: -1;
}

.hero-background::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -10%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, var(--color-primary) 0%, transparent 70%);
  opacity: 0.15;
  animation: float 20s ease-in-out infinite;
}

.hero-background::after {
  content: '';
  position: absolute;
  bottom: -30%;
  left: -5%;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, var(--color-secondary) 0%, transparent 70%);
  opacity: 0.15;
  animation: float 25s ease-in-out infinite reverse;
}

@keyframes float {
  0%,
  100% {
    transform: translate(0, 0) rotate(0deg);
  }
  33% {
    transform: translate(30px, -30px) rotate(120deg);
  }
  66% {
    transform: translate(-20px, 20px) rotate(240deg);
  }
}

.hero-content {
  text-align: center;
  max-width: 800px;
  padding: var(--spacing-lg);
}

.hero-image {
  width: 180px;
  height: 180px;
  border-radius: var(--radius-full);
  object-fit: cover;
  margin: 0 auto var(--spacing-lg);
  border: 4px solid var(--color-surface);
  box-shadow: var(--shadow-lg);
  animation: fadeInScale 1s ease-out;
}

.hero-title {
  margin-bottom: var(--spacing-md);
  animation: fadeInUp 1s ease-out 0.2s both;
}

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

.hero-subtitle {
  font-size: 1.5rem;
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-md);
  animation: fadeInUp 1s ease-out 0.4s both;
}

.cursor {
  animation: blink 1s step-end infinite;
}

@keyframes blink {
  50% {
    opacity: 0;
  }
}

.hero-description {
  font-size: 1.125rem;
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-xl);
  animation: fadeInUp 1s ease-out 0.6s both;
}

.hero-buttons {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: var(--spacing-xl);
  animation: fadeInUp 1s ease-out 0.8s both;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-sm) var(--spacing-lg);
  border-radius: var(--radius-full);
  font-weight: 600;
  transition: all var(--transition-normal);
  border: none;
  cursor: pointer;
}

.btn-primary {
  background: var(--gradient-primary);
  color: white;
  box-shadow: var(--shadow-md);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.btn-secondary {
  background: var(--color-surface);
  color: var(--color-text);
  border: 2px solid var(--color-border);
}

.btn-secondary:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  transform: translateY(-2px);
}

.hero-social {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
  animation: fadeInUp 1s ease-out 1s both;
}

.hero-social a {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-surface);
  border-radius: var(--radius-full);
  color: var(--color-text);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-normal);
}

.hero-social a:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  color: var(--color-primary);
}

/* ================================
   About Section
   ================================ */

.about-content {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-xl);
}

@media (min-width: 768px) {
  .about-content {
    grid-template-columns: 2fr 1fr;
  }
}

.about-text p {
  font-size: 1.125rem;
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-md);
}

.skills h3 {
  margin-bottom: var(--spacing-md);
}

.skills-grid {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

.skill-tag {
  padding: var(--spacing-xs) var(--spacing-md);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  font-size: 0.875rem;
  font-weight: 500;
  transition: all var(--transition-normal);
}

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

/* ================================
   Experience Timeline
   ================================ */

.timeline {
  max-width: 800px;
  margin: 0 auto;
  position: relative;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 20px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--gradient-primary);
}

.timeline-item {
  position: relative;
  padding-left: var(--spacing-3xl);
  margin-bottom: var(--spacing-xl);
}

.timeline-dot {
  position: absolute;
  left: 12px;
  top: 6px;
  width: 20px;
  height: 20px;
  border-radius: var(--radius-full);
  background: var(--gradient-primary);
  box-shadow: var(--shadow-md);
  z-index: 1;
}

.timeline-content {
  background: var(--color-background);
  padding: var(--spacing-lg);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-normal);
}

.timeline-content:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.timeline-content h3 {
  margin-bottom: var(--spacing-xs);
}

.timeline-period {
  color: var(--color-primary);
  font-weight: 600;
  font-size: 0.875rem;
  margin-bottom: var(--spacing-sm);
}

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

/* ================================
   Projects Section
   ================================ */

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

.project-card {
  background: var(--color-background);
  padding: var(--spacing-lg);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-normal);
  border: 1px solid var(--color-border);
}

.project-card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
  border-color: var(--color-primary);
}

.project-header {
  display: flex;
  justify-content: space-between;
  align-items: start;
  margin-bottom: var(--spacing-md);
}

.project-header h3 {
  flex: 1;
}

.project-link {
  color: var(--color-text-secondary);
  transition: all var(--transition-fast);
}

.project-link:hover {
  color: var(--color-primary);
  transform: translateX(4px);
}

.project-description {
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-md);
}

.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
}

.tag {
  padding: 0.25rem 0.75rem;
  background: var(--gradient-primary);
  color: white;
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 500;
}

/* ================================
   Contact Section
   ================================ */

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

.contact-text {
  font-size: 1.125rem;
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-xl);
}

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

.contact-link {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-md) var(--spacing-lg);
  background: var(--color-background);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  color: var(--color-text);
  font-weight: 500;
  transition: all var(--transition-normal);
}

.contact-link:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
}

/* ================================
   Footer
   ================================ */

.footer {
  background: var(--color-surface);
  padding: var(--spacing-xl) 0;
  text-align: center;
  border-top: 1px solid var(--color-border);
}

.footer p {
  color: var(--color-text-secondary);
  margin: 0;
}

/* ================================
   Animations
   ================================ */

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeInScale {
  from {
    opacity: 0;
    transform: scale(0.8);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: all var(--transition-slow);
}

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

/* ================================
   Responsive Design
   ================================ */

@media (max-width: 767px) {
  :root {
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
  }

  .hero-buttons {
    flex-direction: column;
    align-items: stretch;
  }

  .btn {
    justify-content: center;
  }

  .timeline::before {
    left: 10px;
  }

  .timeline-dot {
    left: 2px;
  }

  .timeline-item {
    padding-left: var(--spacing-xl);
  }
}