/* ========================================
   CSS Custom Properties (Design Tokens)
   ======================================== */
:root {
  /* Color Palette */
  --color-primary: #1f3d64;
  --color-primary-dark: #152d4a;
  --color-primary-light: #2a5182;
  --color-secondary: #ffc107;
  --color-accent: #ff6b35;
  --color-success: #4caf50;
  --color-info: #2196f3;
  
  /* Neutral Colors */
  --color-text-primary: #333333;
  --color-text-secondary: #666666;
  --color-text-light: #ffffff;
  --color-bg-primary: #ffffff;
  --color-bg-secondary: #f4f4f4;
  --color-bg-tertiary: #e8e8e8;
  
  /* Spacing */
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
  --spacing-xxl: 4rem;
  
  /* Typography */
  --font-primary: 'Open Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'Fira Code', 'Courier New', monospace;
  
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 2rem;
  --font-size-4xl: 2.5rem;
  
  --line-height-tight: 1.2;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.75;
  
  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.12);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.15);
  --shadow-xl: 0 20px 40px rgba(0, 0, 0, 0.2);
  
  /* Border Radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-full: 9999px;
  
  /* Transitions */
  --transition-fast: 150ms ease-in-out;
  --transition-base: 250ms ease-in-out;
  --transition-slow: 400ms ease-in-out;
  
  /* Layout */
  --sidebar-width: 280px;
  --footer-height: 50px;
}

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

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

body {
  font-family: var(--font-primary);
  font-size: var(--font-size-base);
  line-height: var(--line-height-normal);
  color: var(--color-text-primary);
  background-image: 
    linear-gradient(rgba(0, 0, 0, 0.2), rgba(0, 0, 0, 0.2)), 
    url('../images/noise.jpg');
  background-repeat: repeat;
  background-attachment: fixed;
  background-size: 400px 400px;
  background-color: var(--color-bg-primary);
  min-height: 100vh;
  overflow-x: hidden;
}

/* ========================================
   Typography
   ======================================== */
h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  line-height: var(--line-height-tight);
  margin-bottom: var(--spacing-sm);
  color: var(--color-text-primary);
}

h1 { font-size: var(--font-size-3xl); }
h2 { font-size: var(--font-size-2xl); margin-bottom: var(--spacing-md); }
h3 { font-size: var(--font-size-xl); }
h4 { font-size: var(--font-size-lg); }

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

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

a:hover {
  color: var(--color-secondary);
  text-decoration: underline;
}

strong, b {
  font-weight: 600;
}

em, i {
  font-style: italic;
}

/* ========================================
   Sidebar Navigation
   ======================================== */
.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--sidebar-width);
  height: 100vh;
  background: linear-gradient(180deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
  color: var(--color-text-light);
  padding: var(--spacing-xl) var(--spacing-lg);
  z-index: 1000;
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-lg);
  overflow-y: auto;
}

.sidebar header {
  text-align: center;
  margin-bottom: var(--spacing-md);
}

.profile-pic-container {
  position: relative;
  display: inline-block;
  margin-bottom: var(--spacing-md);
}

.profile-pic {
  width: 150px;
  height: 150px;
  border-radius: 50%;
  object-fit: cover;
  border: 4px solid rgba(255, 255, 255, 0.2);
  box-shadow: var(--shadow-lg);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.profile-pic:hover {
  transform: scale(1.05);
  box-shadow: var(--shadow-xl);
}

.sidebar h1 {
  font-size: var(--font-size-2xl);
  color: var(--color-text-light);
  margin-bottom: var(--spacing-xs);
  font-weight: 700;
}

.sidebar p {
  font-size: var(--font-size-sm);
  color: rgba(255, 255, 255, 0.8);
  margin-bottom: var(--spacing-md);
}

/* Social Icons */
.social-icons {
  display: flex;
  justify-content: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-md);
}

.icon {
  font-size: 1.25rem;
  color: var(--color-text-light);
  transition: all var(--transition-base);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: var(--radius-full);
}

.icon:hover {
  color: var(--color-secondary);
  transform: translateY(-2px);
  text-decoration: none;
}

/* Navigation Links */
.sidebar nav {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.sidebar nav a {
  color: rgba(255, 255, 255, 0.85);
  text-decoration: none;
  padding: 0.5rem 0.75rem;
  border-radius: var(--radius-md);
  font-size: 0.95rem;
  font-weight: 500;
  transition: all var(--transition-fast);
  position: relative;
  display: block;
}

.sidebar nav a::before {
  content: '';
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 3px;
  height: 0;
  background: var(--color-secondary);
  transition: height var(--transition-base);
  border-radius: var(--radius-full);
}

.sidebar nav a:hover {
  background: rgba(255, 255, 255, 0.1);
  color: var(--color-text-light);
  padding-left: 1.25rem;
}

.sidebar nav a:hover::before {
  height: 70%;
}

.sidebar nav a.active {
  background: rgba(255, 255, 255, 0.15);
  color: var(--color-secondary);
  font-weight: 600;
  padding-left: 1.25rem;
}

.sidebar nav a.active::before {
  height: 70%;
}

/* ========================================
   Main Content Area
   ======================================== */
.main-content {
  margin-left: var(--sidebar-width);
  padding: var(--spacing-xl);
  min-height: 100vh;
  padding-bottom: calc(var(--footer-height) + var(--spacing-xl));
}

section {
  max-width: 900px;
  margin: 0 auto var(--spacing-xl) auto;
  padding: var(--spacing-xl);
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  opacity: 1;
  transform: translateY(0);
  transition: opacity var(--transition-slow), transform var(--transition-slow);
}

section.hidden {
  display: none;
}

section.fade-in {
  animation: fadeInUp 0.6s ease-out forwards;
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Section Headers */
section h2 {
  color: var(--color-primary);
  border-bottom: 3px solid var(--color-secondary);
  padding-bottom: var(--spacing-sm);
  margin-bottom: var(--spacing-lg);
  display: inline-block;
}

/* ========================================
   Content Components
   ======================================== */

/* Alert/Notice Box */
.alert {
  padding: var(--spacing-md);
  border-radius: var(--radius-md);
  margin-bottom: var(--spacing-lg);
  border-left: 4px solid;
  background: rgba(255, 107, 53, 0.1);
  border-color: var(--color-accent);
}

.alert strong {
  color: var(--color-accent);
}

/* Resume Links */
.resume-links {
  display: flex;
  gap: var(--spacing-sm);
  margin: var(--spacing-md) 0;
  flex-wrap: wrap;
}

.resume-links a {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--color-primary);
  color: var(--color-text-light);
  border-radius: var(--radius-md);
  font-weight: 500;
  transition: all var(--transition-base);
  text-decoration: none;
}

.resume-links a:hover {
  background: var(--color-primary-light);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

/* Experience/Education Entry */
article {
  margin-bottom: var(--spacing-xl);
  padding: 0;
  background: transparent;
  border-radius: 0;
  border-left: none;
  transition: all var(--transition-base);
}

article:hover {
  transform: none;
  box-shadow: none;
}

.entry-header {
  display: flex;
  align-items: center;
  margin-bottom: var(--spacing-sm);
  gap: var(--spacing-md);
  flex-wrap: wrap;
}

.years {
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text-light);
  background: var(--color-primary);
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--radius-full);
  white-space: nowrap;
}

.entry-header h3 {
  color: var(--color-info);
  margin-bottom: 0;
  font-size: var(--font-size-lg);
}

article h3 {
  color: var(--color-info);
  margin-bottom: var(--spacing-xs);
  font-size: var(--font-size-lg);
}

article strong {
  color: var(--color-primary);
}

/* Technology Tags */
.tech-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
  margin-top: var(--spacing-sm);
}

.tech-tag {
  font-family: var(--font-mono);
  font-size: var(--font-size-sm);
  color: #c2940b;
  background: rgba(255, 193, 7, 0.144);
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-secondary);
  font-weight: 500;
}

/* Section Dividers */
.section-divider {
  color: var(--color-info);
  font-size: var(--font-size-xl);
  font-weight: 600;
  margin: var(--spacing-xxl) 0 var(--spacing-xl) 0;
  padding-bottom: var(--spacing-sm);
  border-bottom: 2px solid var(--color-bg-tertiary);
}

/* Skip Link for Accessibility */
.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--color-secondary);
  color: var(--color-text-primary);
  padding: var(--spacing-xs) var(--spacing-md);
  text-decoration: none;
  font-weight: 600;
  z-index: 100;
  transition: top var(--transition-fast);
}

.skip-link:focus {
  top: 0;
}

/* ========================================
   Footer
   ======================================== */
footer {
  position: fixed;
  bottom: 0;
  left: var(--sidebar-width);
  right: 0;
  height: var(--footer-height);
  background: rgba(15, 19, 24, 0.95);
  backdrop-filter: blur(10px);
  display: flex;
  justify-content: flex-end;
  align-items: center;
  padding: 0 var(--spacing-lg);
  color: rgba(255, 255, 255, 0.5);
  font-size: var(--font-size-sm);
  z-index: 999;
}

footer a {
  color: var(--color-secondary);
  font-weight: 500;
  margin: 0 var(--spacing-xs);
}

footer a:hover {
  color: var(--color-text-light);
  text-decoration: none;
}

/* ========================================
   Focus Styles for Accessibility
   ======================================== */
.sidebar nav a:focus,
.icon:focus,
.resume-links a:focus,
article h3 a:focus,
footer a:focus {
  outline: 2px solid var(--color-secondary);
  outline-offset: 2px;
}

.sidebar nav a:focus {
  outline-offset: -2px;
}

/* ========================================
   Animations
   ======================================== */
@keyframes slideInRight {
  from {
    transform: translateX(100%);
    opacity: 0;
  }
  to {
    transform: translateX(0);
    opacity: 1;
  }
}

@keyframes slideOutRight {
  from {
    transform: translateX(0);
    opacity: 1;
  }
  to {
    transform: translateX(100%);
    opacity: 0;
  }
}

/* ========================================
   Utility Classes
   ======================================== */
.hidden {
  display: none !important;
}

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

.mt-sm { margin-top: var(--spacing-sm); }
.mt-md { margin-top: var(--spacing-md); }
.mt-lg { margin-top: var(--spacing-lg); }
.mb-sm { margin-bottom: var(--spacing-sm); }
.mb-md { margin-bottom: var(--spacing-md); }
.mb-lg { margin-bottom: var(--spacing-lg); }

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

/* Tablets */
@media (max-width: 968px) {
  :root {
    --sidebar-width: 240px;
    --font-size-base: 0.95rem;
  }
  
  .main-content {
    padding: var(--spacing-lg);
  }
  
  section {
    padding: var(--spacing-lg);
  }
}

/* Mobile Landscape & Small Tablets */
@media (max-width: 768px) {
  :root {
    --sidebar-width: 100%;
    --font-size-base: 0.9rem;
  }
  
  .sidebar {
    position: relative;
    width: 100%;
    height: auto;
    padding: var(--spacing-lg);
  }
  
  .sidebar nav {
    flex-direction: row;
    flex-wrap: wrap;
    justify-content: center;
  }
  
  .sidebar nav a {
    flex: 1 1 auto;
    text-align: center;
    min-width: 120px;
  }
  
  .main-content {
    margin-left: 0;
    padding: var(--spacing-md);
  }
  
  footer {
    left: 0;
    justify-content: center;
  }
  
  .profile-pic {
    width: 120px;
    height: 120px;
  }
  
  .entry-header {
    flex-direction: column;
  }
  
  section {
    padding: var(--spacing-md);
  }
}

/* Mobile Portrait */
@media (max-width: 480px) {
  :root {
    --font-size-base: 0.875rem;
    --spacing-xl: 2rem;
  }
  
  .sidebar {
    padding: var(--spacing-md);
  }
  
  .sidebar h1 {
    font-size: var(--font-size-xl);
  }
  
  .profile-pic {
    width: 100px;
    height: 100px;
  }
  
  .main-content {
    padding: var(--spacing-sm);
  }
  
  section {
    padding: var(--spacing-sm) var(--spacing-md);
  }
  
  article {
    padding: var(--spacing-md);
  }
  
  .social-icons {
    gap: var(--spacing-xs);
  }
  
  .icon {
    width: 36px;
    height: 36px;
    font-size: 1.25rem;
  }
  
  footer {
    font-size: var(--font-size-xs);
    padding: 0 var(--spacing-sm);
    height: 40px;
  }
}

/* Print Styles */
@media print {
  .sidebar,
  footer {
    display: none;
  }
  
  .main-content {
    margin-left: 0;
  }
  
  section {
    page-break-inside: avoid;
    box-shadow: none;
    border: 1px solid #ddd;
  }
}