/* ============================================
   PIYUSH PANDEY - PORTFOLIO
   Minimal. Monochrome. Engineer-first.
   ============================================ */

/* CSS Custom Properties */
:root {
  /* Colors - Strict Monochrome */
  --color-bg: #000000;
  --color-bg-elevated: #0a0a0a;
  --color-text: #ffffff;
  --color-text-secondary: #a0a0a0;
  --color-text-tertiary: #666666;
  --color-border: #1a1a1a;
  
  /* Typography */
  --font-primary: 'Outfit', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  
  /* Spacing */
  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 1.5rem;
  --space-lg: 2rem;
  --space-xl: 3rem;
  --space-2xl: 4rem;
  --space-3xl: 6rem;
  --space-4xl: 8rem;
  
  /* Layout */
  --max-width: 1200px;
  --content-width: 800px;
  
  /* Animation */
  --ease-out-expo: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-out-quart: cubic-bezier(0.25, 1, 0.5, 1);
  --duration-fast: 200ms;
  --duration-normal: 400ms;
  --duration-slow: 800ms;
  --duration-slower: 1200ms;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-primary);
  font-weight: 400;
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  overflow-x: hidden;
}

/* Reduced Motion */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  
  html {
    scroll-behavior: auto;
  }
}

/* Selection */
::selection {
  background: var(--color-text);
  color: var(--color-bg);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  line-height: 1.2;
  letter-spacing: -0.02em;
}

h1 {
  font-size: clamp(3rem, 10vw, 7rem);
  font-weight: 700;
  letter-spacing: -0.04em;
}

h2 {
  font-size: clamp(2rem, 5vw, 3rem);
}

h3 {
  font-size: clamp(1.25rem, 2.5vw, 1.5rem);
}

p {
  font-size: 1.125rem;
  color: var(--color-text-secondary);
}

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

strong {
  font-weight: 600;
  color: var(--color-text);
}

code {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  font-weight: 400;
  color: var(--color-text);
  background: var(--color-bg-elevated);
  padding: 0.2em 0.5em;
  border-radius: 2px;
}

ul {
  list-style: none;
}

/* Layout */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

.section {
  padding: var(--space-4xl) 0;
}

.section-title {
  margin-bottom: var(--space-3xl);
  font-size: clamp(2rem, 5vw, 2.5rem);
  color: var(--color-text);
}

/* Navigation */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  padding: var(--space-md) 0;
  background: rgba(0, 0, 0, 0.8);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
}

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

.nav-logo {
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.nav-links {
  display: flex;
  gap: var(--space-lg);
}

.nav-links a {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-secondary);
  transition: color var(--duration-fast) var(--ease-out-quart);
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 1px;
  background: var(--color-text);
  transition: width var(--duration-normal) var(--ease-out-expo);
}

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

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

/* Hero Section */
.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: var(--space-4xl) var(--space-lg);
  position: relative;
}

.hero-content {
  max-width: var(--max-width);
  margin: 0 auto;
  width: 100%;
}

.hero-greeting {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.2em;
  margin-bottom: var(--space-md);
}

.hero-name {
  margin-bottom: var(--space-lg);
  color: var(--color-text);
}

.hero-statement {
  font-size: clamp(1.25rem, 2.5vw, 1.5rem);
  color: var(--color-text-secondary);
  max-width: 600px;
  margin-bottom: var(--space-2xl);
  line-height: 1.5;
}

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

/* Buttons */
.btn {
  display: inline-block;
  font-family: var(--font-primary);
  font-size: 0.875rem;
  font-weight: 500;
  padding: var(--space-sm) var(--space-lg);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all var(--duration-normal) var(--ease-out-expo);
}

.btn-primary {
  background: var(--color-text);
  color: var(--color-bg);
  border-color: var(--color-text);
}

.btn-primary:hover {
  background: transparent;
  color: var(--color-text);
}

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

.btn-secondary:hover {
  border-color: var(--color-text);
}

/* Scroll Indicator */
.scroll-indicator {
  position: absolute;
  bottom: var(--space-2xl);
  left: var(--space-lg);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.scroll-indicator span {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--color-text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.scroll-line {
  width: 60px;
  height: 1px;
  background: var(--color-text-tertiary);
  position: relative;
  overflow: hidden;
}

.scroll-line::after {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: var(--color-text);
  animation: scroll-line 2s var(--ease-out-expo) infinite;
}

@keyframes scroll-line {
  0% { left: -100%; }
  50% { left: 0; }
  100% { left: 100%; }
}

/* About Section */
.about-content {
  max-width: var(--content-width);
}

.about-text {
  font-size: 1.25rem;
  line-height: 1.8;
  margin-bottom: var(--space-lg);
  color: var(--color-text-secondary);
}

.about-text:last-child {
  margin-bottom: 0;
}

/* Skills Section */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--space-2xl);
}

.skill-category-title {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--color-text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.15em;
  margin-bottom: var(--space-md);
}

.skill-list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
}

.skill-list li code {
  display: inline-block;
  background: transparent;
  border: 1px solid var(--color-border);
  padding: 0.4em 0.8em;
  transition: border-color var(--duration-fast) var(--ease-out-quart);
}

.skill-list li code:hover {
  border-color: var(--color-text-tertiary);
}

/* Experience Section */
.timeline {
  position: relative;
  max-width: var(--content-width);
}

.timeline::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 1px;
  background: var(--color-border);
}

.timeline-item {
  position: relative;
  padding-left: var(--space-2xl);
  padding-bottom: var(--space-3xl);
}

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

.timeline-marker {
  position: absolute;
  left: -4px;
  top: 8px;
  width: 9px;
  height: 9px;
  background: var(--color-bg);
  border: 2px solid var(--color-text-tertiary);
  border-radius: 50%;
}

.timeline-header {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: var(--space-sm);
  margin-bottom: var(--space-xs);
}

.timeline-role {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--color-text);
}

.timeline-date code {
  font-size: 0.75rem;
  color: var(--color-text-tertiary);
  background: transparent;
  padding: 0;
}

.timeline-company {
  font-size: 0.875rem;
  color: var(--color-text-tertiary);
  margin-bottom: var(--space-md);
}

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

.timeline-achievements li {
  font-size: 1rem;
  color: var(--color-text-secondary);
  padding-left: var(--space-md);
  position: relative;
}

.timeline-achievements li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.7em;
  width: 4px;
  height: 1px;
  background: var(--color-text-tertiary);
}

/* Projects Section */
.projects-grid {
  display: grid;
  gap: var(--space-lg);
}

.project-card {
  background: var(--color-bg-elevated);
  padding: var(--space-xl);
  position: relative;
  transition: transform var(--duration-slow) var(--ease-out-expo);
}

.project-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--color-border);
  transition: background var(--duration-fast) var(--ease-out-quart);
}

.project-card:hover {
  transform: translateY(-4px);
}

.project-card:hover::before {
  background: var(--color-text-tertiary);
}

.project-title {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: var(--space-xs);
}

.project-year {
  margin-bottom: var(--space-lg);
}

.project-year code {
  font-size: 0.75rem;
  color: var(--color-text-tertiary);
  background: transparent;
  padding: 0;
}

.project-details {
  display: grid;
  gap: var(--space-md);
  margin-bottom: var(--space-lg);
}

.project-block {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.project-label {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--color-text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.project-block p {
  font-size: 1rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
}

.project-tech {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
}

.project-tech code {
  font-size: 0.75rem;
  background: transparent;
  border: 1px solid var(--color-border);
  padding: 0.3em 0.6em;
}

/* Achievements Section */
.achievements-list {
  max-width: var(--content-width);
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

.achievement-item {
  font-size: 1.125rem;
  color: var(--color-text-secondary);
  padding-left: var(--space-lg);
  position: relative;
  line-height: 1.6;
}

.achievement-item::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.75em;
  width: 8px;
  height: 1px;
  background: var(--color-text-tertiary);
}

/* Contact Section */
.contact {
  padding-bottom: var(--space-3xl);
}

.contact-intro {
  font-size: 1.25rem;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-2xl);
  max-width: var(--content-width);
}

.contact-links {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--space-md);
  max-width: var(--content-width);
}

.contact-link {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
  padding: var(--space-md) 0;
  border-top: 1px solid var(--color-border);
  transition: border-color var(--duration-fast) var(--ease-out-quart);
}

.contact-link:hover {
  border-color: var(--color-text-tertiary);
}

.contact-label {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--color-text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.contact-value {
  font-size: 1rem;
  color: var(--color-text);
  transition: color var(--duration-fast) var(--ease-out-quart);
}

.contact-link:hover .contact-value {
  color: var(--color-text-secondary);
}

/* Footer */
.footer {
  padding: var(--space-xl) 0;
  border-top: 1px solid var(--color-border);
}

.footer p {
  font-size: 0.875rem;
  color: var(--color-text-tertiary);
  text-align: center;
}

/* Reveal Animations */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: 
    opacity var(--duration-slower) var(--ease-out-expo),
    transform var(--duration-slower) var(--ease-out-expo);
}

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

/* Staggered Reveal */
.reveal:nth-child(1) { transition-delay: 0ms; }
.reveal:nth-child(2) { transition-delay: 100ms; }
.reveal:nth-child(3) { transition-delay: 200ms; }
.reveal:nth-child(4) { transition-delay: 300ms; }
.reveal:nth-child(5) { transition-delay: 400ms; }
.reveal:nth-child(6) { transition-delay: 500ms; }

/* Hero-specific stagger */
.hero .reveal:nth-child(1) { transition-delay: 200ms; }
.hero .reveal:nth-child(2) { transition-delay: 400ms; }
.hero .reveal:nth-child(3) { transition-delay: 600ms; }
.hero .reveal:nth-child(4) { transition-delay: 800ms; }
.hero .reveal:nth-child(5) { transition-delay: 1000ms; }

/* Responsive */
@media (max-width: 768px) {
  :root {
    --space-4xl: 5rem;
    --space-3xl: 4rem;
  }
  
  .nav-links {
    display: none;
  }
  
  .hero {
    padding-top: var(--space-4xl);
  }
  
  .hero-cta {
    flex-direction: column;
    align-items: flex-start;
  }
  
  .btn {
    width: 100%;
    text-align: center;
  }
  
  .scroll-indicator {
    display: none;
  }
  
  .timeline::before {
    left: 4px;
  }
  
  .timeline-marker {
    left: 0;
  }
  
  .timeline-item {
    padding-left: var(--space-xl);
  }
  
  .project-card {
    padding: var(--space-lg);
  }
  
  .skills-grid {
    grid-template-columns: 1fr 1fr;
    gap: var(--space-xl);
  }
}

@media (max-width: 480px) {
  .skills-grid {
    grid-template-columns: 1fr;
  }
  
  .contact-links {
    grid-template-columns: 1fr;
  }
  
  .timeline-header {
    flex-direction: column;
    gap: var(--space-xs);
  }
}

/* Loader */
.loader {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 9999;
  background: var(--color-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: opacity 0.6s var(--ease-out-expo), visibility 0.6s;
}

.loader.hidden {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

.loader-line {
  width: 60px;
  height: 1px;
  background: var(--color-border);
  position: relative;
  overflow: hidden;
}

.loader-line::after {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: var(--color-text);
  animation: loader-progress 1.2s var(--ease-out-expo) infinite;
}

@keyframes loader-progress {
  0% { left: -100%; width: 100%; }
  50% { left: 0; width: 100%; }
  100% { left: 100%; width: 100%; }
}

/* Custom Cursor */
.cursor,
.cursor-follower {
  display: none;
}

@media (pointer: fine) {
  .cursor,
  .cursor-follower {
    display: block;
    position: fixed;
    top: 0;
    left: 0;
    pointer-events: none;
    z-index: 10000;
    mix-blend-mode: difference;
  }
  
  .cursor {
    width: 8px;
    height: 8px;
    background: var(--color-text);
    border-radius: 50%;
    transform: translate(-50%, -50%);
  }
  
  .cursor-follower {
    width: 32px;
    height: 32px;
    border: 1px solid var(--color-text);
    border-radius: 50%;
    transform: translate(-50%, -50%);
    transition: 
      width 0.3s var(--ease-out-expo),
      height 0.3s var(--ease-out-expo),
      opacity 0.3s var(--ease-out-expo);
  }
  
  .cursor-follower.hover {
    width: 48px;
    height: 48px;
    opacity: 0.5;
  }
  
  body {
    cursor: none;
  }
  
  a, button {
    cursor: none;
  }
}

/* Mobile Navigation Toggle */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 6px;
  width: 40px;
  height: 40px;
  background: transparent;
  border: none;
  cursor: pointer;
  z-index: 1001;
}

.nav-toggle-line {
  display: block;
  width: 24px;
  height: 1px;
  background: var(--color-text);
  transition: transform 0.3s var(--ease-out-expo), opacity 0.3s;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-line:first-child {
  transform: translateY(3.5px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-line:last-child {
  transform: translateY(-3.5px) rotate(-45deg);
}

@media (max-width: 768px) {
  .nav-toggle {
    display: flex;
  }
  
  .nav-links {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--color-bg);
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: var(--space-xl);
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.4s var(--ease-out-expo), visibility 0.4s;
  }
  
  .nav-links.active {
    display: flex;
    opacity: 1;
    visibility: visible;
  }
  
  .nav-links a {
    font-size: 1.5rem;
  }
}

/* Focus States */
.keyboard-nav a:focus,
.keyboard-nav button:focus {
  outline: 1px solid var(--color-text);
  outline-offset: 4px;
}

a:focus-visible,
button:focus-visible {
  outline: 1px solid var(--color-text);
  outline-offset: 4px;
}

/* Skip Link */
.skip-link {
  position: absolute;
  top: -100%;
  left: var(--space-lg);
  background: var(--color-text);
  color: var(--color-bg);
  padding: var(--space-sm) var(--space-md);
  z-index: 10001;
  transition: top 0.3s;
}

.skip-link:focus {
  top: var(--space-md);
}

/* Print Styles */
@media print {
  .nav,
  .scroll-indicator,
  .hero-cta,
  .loader,
  .cursor,
  .cursor-follower {
    display: none;
  }
  
  .section {
    padding: var(--space-lg) 0;
    break-inside: avoid;
  }
  
  .reveal {
    opacity: 1;
    transform: none;
  }
}