/* ========================================
   Layout Styles
   Sidebar + Main Content Layout
   ======================================== */

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-family-primary);
  font-size: var(--text-base);
  line-height: var(--leading-normal);
  color: var(--text-primary);
  background-color: var(--bg-secondary);
  min-height: 100vh;
  overflow-x: hidden;
  transition: background-color var(--transition-base), color var(--transition-base);
}

/* =========================
   Page Loading Animation
   ========================= */
.page-loader {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: var(--bg-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 9999;
  opacity: 1;
  transition: opacity 0.5s ease, visibility 0.5s ease;
}

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

.loader-content {
  text-align: center;
}

.loader-spinner {
  width: 50px;
  height: 50px;
  border: 3px solid var(--border-color);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin 1s linear infinite;
  margin: 0 auto var(--space-4);
}

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

.loader-content p {
  color: var(--text-muted);
  font-size: var(--text-sm);
}

/* =========================
   Back to Top Button
   ========================= */
.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 50px;
  height: 50px;
  border-radius: var(--radius-xl);
  background: linear-gradient(135deg, var(--color-primary), var(--color-indigo));
  color: white;
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-xl);
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  z-index: var(--z-fixed);
  box-shadow: 0 10px 30px rgba(59, 130, 246, 0.4);
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  transform: translateY(-5px) scale(1.05);
  box-shadow: 0 15px 40px rgba(59, 130, 246, 0.5);
}

.back-to-top:active {
  transform: translateY(-2px) scale(1);
}

/* =========================
   Page Wrapper
   ========================= */
.page-wrapper {
  display: flex;
  min-height: 100vh;
}

/* =========================
   Sidebar Styles
   ========================= */
.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--sidebar-width);
  height: 100vh;
  background: var(--bg-sidebar);
  color: var(--text-on-sidebar);
  display: flex;
  flex-direction: column;
  z-index: var(--z-fixed);
  transition: transform var(--transition-slow);
  overflow-y: auto;
  overflow-x: hidden;
}

/* Circuit pattern decoration */
.sidebar::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-image: 
    radial-gradient(circle at 20% 80%, rgba(255,255,255,0.03) 0%, transparent 50%),
    radial-gradient(circle at 80% 20%, rgba(255,255,255,0.03) 0%, transparent 50%);
  pointer-events: none;
}

/* Sidebar scrollbar styling */
.sidebar::-webkit-scrollbar {
  width: 6px;
}

.sidebar::-webkit-scrollbar-track {
  background: transparent;
}

.sidebar::-webkit-scrollbar-thumb {
  background: rgba(255, 255, 255, 0.2);
  border-radius: var(--radius-full);
}

.sidebar::-webkit-scrollbar-thumb:hover {
  background: rgba(255, 255, 255, 0.3);
}

/* Sidebar Header / Profile Section */
.sidebar-header {
  padding: var(--space-8) var(--space-6);
  text-align: center;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.profile-image-container {
  margin-bottom: var(--space-4);
}

.profile-image {
  width: 150px;
  height: 150px;
  border-radius: var(--radius-full);
  border: 4px solid rgba(255, 255, 255, 0.3);
  object-fit: cover;
  transition: var(--transition-all);
}

.profile-image:hover {
  border-color: rgba(255, 255, 255, 0.6);
  transform: scale(1.02);
}

.sidebar-name {
  font-family: var(--font-family-heading);
  font-size: var(--text-xl);
  font-weight: var(--font-bold);
  margin-bottom: var(--space-2);
  color: #fff;
}

.sidebar-title {
  font-size: var(--text-sm);
  color: rgba(255, 255, 255, 0.8);
  font-weight: var(--font-normal);
}

/* Sidebar Navigation */
.sidebar-nav {
  flex: 1;
  padding: var(--space-6) 0;
}

.sidebar-nav ul {
  list-style: none;
}

.sidebar-nav li {
  margin: 0;
}

.sidebar-nav a {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-6);
  color: rgba(255, 255, 255, 0.85);
  text-decoration: none;
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  transition: var(--transition-all);
  border-left: 3px solid transparent;
}

.sidebar-nav a:hover,
.sidebar-nav a.active {
  background: var(--bg-sidebar-hover);
  color: #fff;
  border-left-color: var(--color-accent);
}

.sidebar-nav a i {
  font-size: var(--text-lg);
  width: 24px;
  text-align: center;
}

/* Sidebar Footer / Social Links */
.sidebar-footer {
  padding: var(--space-6);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.sidebar-social {
  display: flex;
  justify-content: center;
  gap: var(--space-4);
  margin-bottom: var(--space-4);
}

.sidebar-social a {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  background: rgba(255, 255, 255, 0.1);
  color: rgba(255, 255, 255, 0.9);
  font-size: var(--text-lg);
  text-decoration: none;
  transition: var(--transition-all);
}

.sidebar-social a:hover {
  background: var(--color-accent);
  color: #fff;
  transform: translateY(-2px);
}

/* Theme Toggle in Sidebar */
.theme-toggle-container {
  display: flex;
  justify-content: center;
  margin-top: var(--space-4);
}

.theme-toggle {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: var(--radius-full);
  color: rgba(255, 255, 255, 0.9);
  font-size: var(--text-sm);
  cursor: pointer;
  transition: var(--transition-all);
}

.theme-toggle:hover {
  background: rgba(255, 255, 255, 0.2);
}

.theme-toggle i {
  font-size: var(--text-base);
}

/* =========================
   Main Content Area
   ========================= */
.main-content {
  flex: 1;
  margin-left: var(--sidebar-width);
  min-height: 100vh;
  transition: margin-left var(--transition-slow);
}

/* =========================
   Section Styles
   ========================= */
.section {
  padding: var(--space-16) var(--space-8);
  max-width: var(--content-max-width);
  margin: 0 auto;
}

.section:first-of-type {
  padding-top: var(--space-12);
}

.section-alt {
  background-color: var(--bg-primary);
}

/* Section animations */
.section {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.section.animate-in {
  opacity: 1;
  transform: translateY(0);
}

/* Section Header */
.section-header {
  margin-bottom: var(--space-10);
  text-align: center;
}

.section-title {
  font-family: var(--font-family-heading);
  font-size: var(--text-3xl);
  font-weight: var(--font-bold);
  color: var(--color-primary);
  margin-bottom: var(--space-3);
  position: relative;
  display: inline-block;
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: -8px;
  left: 50%;
  transform: translateX(-50%);
  width: 60px;
  height: 4px;
  background: linear-gradient(90deg, var(--color-primary), var(--color-accent), var(--color-purple));
  border-radius: var(--radius-full);
}

.section-subtitle {
  font-size: var(--text-base);
  color: var(--text-muted);
  max-width: 600px;
  margin: var(--space-4) auto 0;
  line-height: var(--leading-relaxed);
}

/* =========================
   Hero Section (About)
   ========================= */
.hero-section {
  background: linear-gradient(135deg, #4f8fff 0%, #3b82f6 50%, #6366f1 100%);
  padding: var(--space-12) var(--space-8);
  border-bottom: 1px solid var(--border-color);
  color: #ffffff;
  position: relative;
  overflow: hidden;
}

/* Animated floating shapes */
.hero-section::before {
  content: '';
  position: absolute;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(255,255,255,0.15) 0%, transparent 70%);
  top: -200px;
  right: -100px;
  animation: float 6s ease-in-out infinite;
  pointer-events: none;
}

.hero-section::after {
  content: '';
  position: absolute;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(16, 185, 129, 0.15) 0%, transparent 70%);
  bottom: -150px;
  left: -100px;
  animation: float 8s ease-in-out infinite reverse;
  pointer-events: none;
}

[data-theme="dark"] .hero-section {
  background: linear-gradient(135deg, #1e293b 0%, #0f172a 100%);
}

.hero-content {
  max-width: 900px;
  margin: 0 auto;
  text-align: center;
  position: relative;
  z-index: 1;
}

/* Terminal Widget */
.terminal-widget {
  background: rgba(0, 0, 0, 0.3);
  backdrop-filter: blur(10px);
  border-radius: var(--radius-xl);
  border: 1px solid rgba(255, 255, 255, 0.1);
  max-width: 500px;
  margin: 0 auto var(--space-8);
  overflow: hidden;
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
}

.terminal-header {
  background: rgba(0, 0, 0, 0.3);
  padding: var(--space-2) var(--space-4);
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.terminal-dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
}

.terminal-dot.red { background: #ef4444; }
.terminal-dot.yellow { background: #eab308; }
.terminal-dot.green { background: #22c55e; }

.terminal-title {
  margin-left: auto;
  font-family: var(--font-family-mono);
  font-size: var(--text-xs);
  color: rgba(255, 255, 255, 0.5);
}

.terminal-body {
  padding: var(--space-4);
}

.terminal-line {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-family-mono);
  font-size: var(--text-sm);
}

.terminal-prompt {
  color: var(--color-accent);
}

.terminal-command {
  color: #ffffff;
}

.terminal-cursor {
  animation: blink 1s infinite;
  color: var(--color-accent);
}

/* Hero Stats Badges */
.hero-stats {
  display: flex;
  justify-content: center;
  gap: var(--space-4);
  margin-bottom: var(--space-6);
  flex-wrap: wrap;
}

.stat-badge {
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: var(--radius-xl);
  padding: var(--space-3) var(--space-5);
  text-align: center;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.stat-badge:hover {
  transform: translateY(-3px);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
}

.stat-badge.accent {
  background: rgba(16, 185, 129, 0.2);
  border-color: rgba(16, 185, 129, 0.3);
}

.stat-badge.purple {
  background: rgba(139, 92, 246, 0.2);
  border-color: rgba(139, 92, 246, 0.3);
}

.stat-badge.orange {
  background: rgba(245, 158, 11, 0.2);
  border-color: rgba(245, 158, 11, 0.3);
}

.stat-value {
  display: block;
  font-family: var(--font-family-heading);
  font-size: var(--text-2xl);
  font-weight: var(--font-bold);
  color: #ffffff;
  line-height: 1;
}

.stat-label {
  display: block;
  font-size: var(--text-xs);
  color: rgba(255, 255, 255, 0.7);
  margin-top: var(--space-1);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.hero-intro {
  margin-bottom: var(--space-6);
}

.hero-greeting {
  font-size: var(--text-lg);
  color: var(--color-accent);
  font-weight: var(--font-semibold);
  margin-bottom: var(--space-2);
}

[data-theme="dark"] .hero-greeting {
  color: #34d399;
}

.hero-name {
  font-family: var(--font-family-heading);
  font-size: var(--text-4xl);
  font-weight: var(--font-bold);
  color: #ffffff;
  margin-bottom: var(--space-3);
  line-height: var(--leading-tight);
}

.hero-title {
  font-size: var(--text-xl);
  color: rgba(255, 255, 255, 0.9);
  font-weight: var(--font-medium);
  margin-bottom: var(--space-4);
}

.hero-specialization {
  display: inline-flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-4);
  background: rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-xl);
  border: 1px solid rgba(255, 255, 255, 0.2);
  margin-bottom: var(--space-6);
  backdrop-filter: blur(10px);
}

.hero-specialization span {
  font-size: var(--text-sm);
  color: rgba(255, 255, 255, 0.95);
}

.hero-specialization i {
  color: var(--color-accent);
}

.hero-description {
  font-size: var(--text-base);
  color: rgba(255, 255, 255, 0.85);
  line-height: var(--leading-relaxed);
  max-width: 700px;
  margin: 0 auto var(--space-8);
}

.hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
  justify-content: center;
}

/* =========================
   Grid System
   ========================= */
.grid {
  display: grid;
  gap: var(--space-6);
}

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

.grid-3 {
  grid-template-columns: repeat(3, 1fr);
}

/* Single column card layout with spacing for Research and Projects */
#research > div > .card-link,
#projects > div > .card-link {
  display: block;
  margin-bottom: var(--space-6);
}

#research > div > .card-link:last-child,
#projects > div > .card-link:last-child {
  margin-bottom: 0;
}

/* Large tablets - 2 columns for grid-2, 1 for grid-3 */
@media (max-width: 1024px) {
  .grid-3 {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* =========================
   Mobile Header (Hidden by default)
   ========================= */
.mobile-header {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: var(--color-primary);
  color: #fff;
  padding: 0 var(--space-4);
  align-items: center;
  justify-content: space-between;
  z-index: var(--z-fixed);
  box-shadow: var(--shadow-md);
}

.mobile-header-logo {
  font-family: var(--font-family-heading);
  font-size: var(--text-lg);
  font-weight: var(--font-bold);
  color: #fff;
  text-decoration: none;
}

.mobile-menu-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  background: transparent;
  border: none;
  color: #fff;
  font-size: var(--text-2xl);
  cursor: pointer;
  border-radius: var(--radius-lg);
  transition: var(--transition-all);
}

.mobile-menu-toggle:hover {
  background: rgba(255, 255, 255, 0.1);
}

/* Sidebar Overlay (for mobile) */
.sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  z-index: calc(var(--z-fixed) - 1);
  opacity: 0;
  transition: opacity var(--transition-base);
}

.sidebar-overlay.active {
  opacity: 1;
}

/* =========================
   Footer
   ========================= */
.footer {
  background: linear-gradient(180deg, var(--bg-secondary) 0%, #dbeafe 100%);
  color: var(--text-primary);
  padding: var(--space-12) var(--space-8) var(--space-8);
  margin-left: 0;
  border-top: 1px solid var(--border-color);
  position: relative;
}

[data-theme="dark"] .footer {
  background: linear-gradient(180deg, var(--bg-secondary) 0%, #0c1525 100%);
  border-top-color: var(--border-color);
}

/* Decorative top accent */
.footer::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--color-primary), var(--color-accent), var(--color-purple));
}

.footer-content {
  max-width: var(--content-max-width);
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: flex-start;
  gap: var(--space-8);
}

.footer-info {
  flex: 1;
  min-width: 250px;
}

.footer-info h4 {
  font-size: var(--text-xl);
  font-weight: var(--font-bold);
  margin-bottom: var(--space-3);
  color: var(--text-primary);
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.footer-info p {
  color: var(--text-secondary);
  font-size: var(--text-sm);
  line-height: var(--leading-relaxed);
  margin-bottom: var(--space-3);
}

.footer-location {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  color: var(--text-muted);
  font-size: var(--text-sm);
}

.footer-location i {
  color: var(--color-accent);
}

.footer-connect {
  text-align: center;
}

.footer-connect h5 {
  font-size: var(--text-lg);
  font-weight: var(--font-semibold);
  margin-bottom: var(--space-4);
  color: var(--text-primary);
}

.footer-social {
  display: flex;
  gap: var(--space-3);
}

.footer-social a {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: var(--radius-xl);
  background: var(--bg-primary);
  color: var(--color-primary);
  font-size: var(--text-lg);
  text-decoration: none;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  border: 1px solid var(--border-color);
}

.footer-social a:hover {
  background: var(--color-primary);
  color: white;
  transform: translateY(-4px) scale(1.05);
  box-shadow: 0 10px 20px rgba(59, 130, 246, 0.3);
  border-color: var(--color-primary);
}

.footer-social a:nth-child(2):hover {
  background: #0077b5;
  border-color: #0077b5;
}

.footer-social a:nth-child(4):hover {
  background: #e4405f;
  border-color: #e4405f;
}

.footer-social a:nth-child(5):hover {
  background: #1877f2;
  border-color: #1877f2;
}

[data-theme="dark"] .footer-social a {
  background: var(--bg-tertiary);
  border-color: var(--border-color);
}

.footer-bottom {
  width: 100%;
  padding-top: var(--space-6);
  border-top: 1px solid var(--border-color);
  margin-top: var(--space-6);
  text-align: center;
}

.footer-bottom p {
  color: var(--text-muted);
  font-size: var(--text-sm);
}

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

/* Large Tablets and Small Desktops */
@media (max-width: 1024px) {
  :root {
    --sidebar-width: 260px;
  }
  
  .section {
    padding: var(--space-12) var(--space-6);
  }
  
  .grid-3 {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* Tablets */
@media (max-width: 768px) {
  /* Show mobile header, hide sidebar by default */
  .mobile-header {
    display: flex;
  }
  
  .sidebar {
    transform: translateX(-100%);
    width: 280px;
  }
  
  .sidebar.open {
    transform: translateX(0);
  }
  
  .sidebar-overlay {
    display: block;
  }
  
  .main-content {
    margin-left: 0;
    padding-top: var(--header-height);
  }
  
  .footer {
    margin-left: 0;
  }
  
  .section {
    padding: var(--space-10) var(--space-4);
  }
  
  .hero-section {
    padding: var(--space-8) var(--space-4);
  }
  
  .hero-name {
    font-size: var(--text-3xl);
  }
  
  .section-title {
    font-size: var(--text-2xl);
  }
  
  .grid-2,
  .grid-3,
  .grid-auto {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .hero-cta {
    flex-direction: column;
  }
}

/* Mobile Phones */
@media (max-width: 480px) {
  .grid-2,
  .grid-3,
  .grid-auto {
    grid-template-columns: 1fr;
  }
  
  .section {
    padding: var(--space-8) var(--space-4);
  }
  
  .hero-name {
    font-size: var(--text-2xl);
  }
  
  .hero-title {
    font-size: var(--text-lg);
  }
  
  .section-title {
    font-size: var(--text-xl);
  }
  
  .section-subtitle {
    font-size: var(--text-sm);
  }
  
  .profile-image {
    width: 120px;
    height: 120px;
  }
  
  .sidebar-name {
    font-size: var(--text-lg);
  }
}

/* =========================
   Print Styles
   ========================= */
@media print {
  .sidebar,
  .mobile-header,
  .theme-toggle,
  .sidebar-overlay {
    display: none !important;
  }
  
  .main-content {
    margin-left: 0;
    padding-top: 0;
  }
  
  .section {
    page-break-inside: avoid;
  }
}