/*
 * Mohamed Samir - Portfolio Design System
 * Premium, engineer-focused visual language
 * Version: 2.0
 */

/* ============================================================================= 
   1. CSS Custom Properties (Design Tokens)
   ============================================================================= */

:root {
  /* Colors - Primary Palette */
  --color-primary: #0a1628;
  --color-primary-light: #1e293b;
  --color-secondary: #3b82f6;
  --color-accent: #06b6d4;
  --color-success: #10b981;

  /* Colors - Surfaces */
  --color-surface-light: #f8fafc;
  --color-surface-white: #ffffff;
  --color-surface-dark: #1e293b;
  --color-surface-darker: #0f172a;

  /* Colors - Text */
  --color-text-primary: #0f172a;
  --color-text-secondary: #64748b;
  --color-text-tertiary: #94a3b8;
  --color-text-inverse: #f8fafc;

  /* Colors - Borders & Dividers */
  --color-border: #e2e8f0;
  --color-border-dark: #334155;

  /* Typography - Font Families */
  --font-sans:
    "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-mono: "JetBrains Mono", "Fira Code", "Consolas", monospace;

  /* Typography - Font Sizes */
  --text-xs: 0.75rem; /* 12px */
  --text-sm: 0.875rem; /* 14px */
  --text-base: 1rem; /* 16px */
  --text-lg: 1.125rem; /* 18px */
  --text-xl: 1.25rem; /* 20px */
  --text-2xl: 1.5rem; /* 24px */
  --text-3xl: 2rem; /* 32px */
  --text-4xl: 2.5rem; /* 40px */
  --text-5xl: 3rem; /* 48px */
  --text-6xl: 3.5rem; /* 56px */

  /* Typography - Font Weights */
  --font-normal: 400;
  --font-medium: 500;
  --font-semibold: 600;
  --font-bold: 700;

  /* Typography - Line Heights */
  --leading-tight: 1.1;
  --leading-snug: 1.3;
  --leading-normal: 1.5;
  --leading-relaxed: 1.7;

  /* Spacing Scale (8px base) */
  --space-1: 0.25rem; /* 4px */
  --space-2: 0.5rem; /* 8px */
  --space-3: 0.75rem; /* 12px */
  --space-4: 1rem; /* 16px */
  --space-5: 1.25rem; /* 20px */
  --space-6: 1.5rem; /* 24px */
  --space-8: 2rem; /* 32px */
  --space-10: 2.5rem; /* 40px */
  --space-12: 3rem; /* 48px */
  --space-16: 4rem; /* 64px */
  --space-20: 5rem; /* 80px */
  --space-24: 6rem; /* 96px */

  /* Layout */
  --max-width: 1200px;
  --max-width-narrow: 800px;

  /* Border Radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md:
    0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
  --shadow-lg:
    0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
  --shadow-xl:
    0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 350ms ease;
}

/* ============================================================================= 
   2. Reset & Base Styles
   ============================================================================= */

*,
*::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;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

body {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  font-weight: var(--font-normal);
  line-height: var(--leading-relaxed);
  color: var(--color-text-primary);
  background-color: var(--color-surface-white);
  overflow-x: hidden;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

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

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

a:focus-visible {
  outline: 2px solid var(--color-secondary);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* ============================================================================= 
   3. Typography
   ============================================================================= */

h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: var(--font-sans);
  font-weight: var(--font-bold);
  color: var(--color-text-primary);
  line-height: var(--leading-snug);
}

.heading-hero {
  font-size: var(--text-5xl);
  font-weight: var(--font-bold);
  line-height: var(--leading-tight);
  letter-spacing: -0.02em;
}

.heading-section {
  font-size: var(--text-3xl);
  font-weight: var(--font-semibold);
  margin-bottom: var(--space-4);
}

.heading-subsection {
  font-size: var(--text-2xl);
  font-weight: var(--font-semibold);
}

.heading-card {
  font-size: var(--text-xl);
  font-weight: var(--font-semibold);
}

.text-lead {
  font-size: var(--text-lg);
  color: var(--color-text-secondary);
  line-height: var(--leading-relaxed);
}

.text-body {
  font-size: var(--text-base);
  color: var(--color-text-secondary);
}

.text-small {
  font-size: var(--text-sm);
  color: var(--color-text-tertiary);
}

.text-mono {
  font-family: var(--font-mono);
}

/* Text Colors */
.text-inverse {
  color: var(--color-text-inverse);
}

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

/* ============================================================================= 
   4. Layout Components
   ============================================================================= */

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-6);
}

.section {
  padding: var(--space-20) 0;
}

.section-dark {
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
}

.section-dark h1,
.section-dark h2,
.section-dark h3,
.section-dark h4,
.section-dark h5,
.section-dark h6 {
  color: var(--color-text-inverse);
}

.section-dark .text-lead,
.section-dark .text-body {
  color: var(--color-text-tertiary);
}

.section-light {
  background-color: var(--color-surface-light);
}

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

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

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

.grid-4 {
  grid-template-columns: repeat(4, 1fr);
}

@media (max-width: 1024px) {
  .grid-3,
  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 640px) {
  .grid-2,
  .grid-3,
  .grid-4 {
    grid-template-columns: 1fr;
  }
}

/* Flex Utilities */
.flex {
  display: flex;
}

.flex-col {
  flex-direction: column;
}

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

.justify-center {
  justify-content: center;
}

.justify-between {
  justify-content: space-between;
}

.gap-2 {
  gap: var(--space-2);
}
.gap-3 {
  gap: var(--space-3);
}
.gap-4 {
  gap: var(--space-4);
}
.gap-6 {
  gap: var(--space-6);
}
.gap-8 {
  gap: var(--space-8);
}

/* ============================================================================= 
   5. Buttons
   ============================================================================= */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  font-family: var(--font-sans);
  font-size: var(--text-base);
  font-weight: var(--font-medium);
  line-height: 1;
  text-decoration: none;
  border: 2px solid transparent;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-base);
}

.btn:focus-visible {
  outline: 2px solid var(--color-secondary);
  outline-offset: 2px;
}

.btn-primary {
  background-color: var(--color-secondary);
  color: var(--color-surface-white);
  border-color: var(--color-secondary);
}

.btn-primary:hover {
  background-color: #2563eb;
  border-color: #2563eb;
  color: var(--color-surface-white);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

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

.btn-secondary:hover {
  background-color: var(--color-surface-light);
  border-color: var(--color-text-tertiary);
  color: var(--color-text-primary);
}

.btn-ghost {
  background-color: transparent;
  color: var(--color-secondary);
  border-color: transparent;
  padding: var(--space-2) var(--space-3);
}

.btn-ghost:hover {
  background-color: rgba(59, 130, 246, 0.1);
  color: var(--color-secondary);
}

/* Dark section button variants */
.section-dark .btn-secondary {
  color: var(--color-text-inverse);
  border-color: var(--color-border-dark);
}

.section-dark .btn-secondary:hover {
  background-color: var(--color-surface-dark);
  border-color: var(--color-text-tertiary);
}

/* ============================================================================= 
   6. Badges & Tags
   ============================================================================= */

.badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-1) var(--space-3);
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  border-radius: var(--radius-full);
  background-color: rgba(59, 130, 246, 0.1);
  color: var(--color-secondary);
}

.badge-success {
  background-color: rgba(16, 185, 129, 0.1);
  color: var(--color-success);
}

.badge::before {
  content: "";
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background-color: currentColor;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%,
  100% {
    opacity: 1;
  }
  50% {
    opacity: 0.5;
  }
}

.tag {
  display: inline-block;
  padding: var(--space-1) var(--space-3);
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  color: var(--color-text-secondary);
  background-color: var(--color-surface-light);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.tag:hover {
  background-color: var(--color-border);
  color: var(--color-text-primary);
}

.tag-primary {
  background-color: rgba(59, 130, 246, 0.1);
  color: var(--color-secondary);
}

.tag-primary:hover {
  background-color: rgba(59, 130, 246, 0.2);
}

/* ============================================================================= 
   7. Cards
   ============================================================================= */

.card {
  background-color: var(--color-surface-white);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border);
  overflow: hidden;
  transition: all var(--transition-base);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl);
  border-color: transparent;
}

.card-image {
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  transition: transform var(--transition-slow);
}

.card:hover .card-image {
  transform: scale(1.02);
}

.card-body {
  padding: var(--space-6);
}

.card-title {
  font-size: var(--text-xl);
  font-weight: var(--font-semibold);
  margin-bottom: var(--space-2);
}

.card-description {
  font-size: var(--text-base);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-4);
}

.card-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-bottom: var(--space-4);
}

.card-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-weight: var(--font-medium);
  color: var(--color-secondary);
}

.card-link:hover {
  gap: var(--space-3);
}

/* ============================================================================= 
   8. Impact Stats
   ============================================================================= */

.stat-card {
  text-align: center;
  padding: var(--space-8);
  background-color: var(--color-surface-white);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border);
  transition:
    transform var(--transition-base),
    box-shadow var(--transition-base);
}

.stat-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.stat-value-wrapper {
  display: flex;
  align-items: baseline;
  justify-content: center;
  gap: 2px;
  margin-bottom: var(--space-2);
}

.stat-value {
  font-size: var(--text-4xl);
  font-weight: var(--font-bold);
  color: var(--color-secondary);
  line-height: 1;
}

.stat-suffix {
  font-size: var(--text-2xl);
  font-weight: var(--font-bold);
  color: var(--color-secondary);
  line-height: 1;
}

.stat-label {
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  color: var(--color-text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* ============================================================================= 
   9. Skills Section
   ============================================================================= */

.skills-group {
  margin-bottom: var(--space-8);
}

.skills-group-title {
  font-size: var(--text-sm);
  font-weight: var(--font-semibold);
  color: var(--color-text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: var(--space-4);
  padding-bottom: var(--space-2);
  border-bottom: 1px solid var(--color-border);
}

.skills-list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.skill-tag {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  color: var(--color-text-primary);
  background-color: var(--color-surface-light);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.skill-tag:hover {
  background-color: var(--color-border);
}

.skill-tag-expert {
  background-color: rgba(59, 130, 246, 0.1);
  color: var(--color-secondary);
}

.skill-tag-expert::after {
  content: "★";
  font-size: var(--text-xs);
}

/* ============================================================================= 
   10. Timeline / Experience
   ============================================================================= */

.timeline {
  position: relative;
}

.timeline::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 2px;
  background-color: var(--color-border);
}

.timeline-item {
  position: relative;
  padding-left: var(--space-8);
  padding-bottom: var(--space-10);
}

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

.timeline-item::before {
  content: "";
  position: absolute;
  left: -5px;
  top: 6px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background-color: var(--color-secondary);
  border: 2px solid var(--color-surface-white);
}

.timeline-header {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: var(--space-2) var(--space-4);
  margin-bottom: var(--space-2);
}

.timeline-role {
  font-size: var(--text-xl);
  font-weight: var(--font-semibold);
  color: var(--color-text-primary);
}

.timeline-company {
  font-size: var(--text-base);
  color: var(--color-text-secondary);
}

.timeline-period {
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  color: var(--color-secondary);
}

.timeline-achievements {
  list-style: none;
  margin-top: var(--space-4);
}

.timeline-achievements li {
  position: relative;
  padding-left: var(--space-5);
  margin-bottom: var(--space-2);
  color: var(--color-text-secondary);
}

.timeline-achievements li::before {
  content: "→";
  position: absolute;
  left: 0;
  color: var(--color-accent);
  font-weight: var(--font-bold);
}

/* ============================================================================= 
   11. Hero Section
   ============================================================================= */

.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  background: linear-gradient(
    135deg,
    var(--color-primary) 0%,
    var(--color-primary-light) 100%
  );
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-image:
    /* Radial glows */
    radial-gradient(
      circle at 20% 80%,
      rgba(59, 130, 246, 0.15) 0%,
      transparent 40%
    ),
    radial-gradient(
      circle at 85% 20%,
      rgba(6, 182, 212, 0.1) 0%,
      transparent 35%
    ),
    radial-gradient(
      circle at 60% 90%,
      rgba(59, 130, 246, 0.08) 0%,
      transparent 30%
    );
  pointer-events: none;
}

/* SVG Network positioning */
.hero-network {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 0;
}

.network-group {
  animation: network-pulse 4s ease-in-out infinite;
}

.network-group:nth-child(2) {
  animation-delay: 1s;
}

.network-group:nth-child(3) {
  animation-delay: 2s;
}

@keyframes network-pulse {
  0%,
  100% {
    opacity: 0.5;
  }
  50% {
    opacity: 0.8;
  }
}

.hero-content {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: var(--space-12);
  align-items: center;
}

.hero-text {
  max-width: 700px;
}

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

.hero-title {
  font-size: var(--text-5xl);
  font-weight: var(--font-bold);
  color: var(--color-text-inverse);
  line-height: var(--leading-tight);
  margin-bottom: var(--space-6);
}

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

.hero-subtitle {
  font-size: var(--text-lg);
  color: var(--color-text-tertiary);
  line-height: var(--leading-relaxed);
  margin-bottom: var(--space-8);
}

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

.hero-image {
  width: 400px;
  height: 400px;
  border-radius: var(--radius-xl);
  object-fit: cover;
  border: 4px solid rgba(255, 255, 255, 0.1);
  box-shadow: var(--shadow-xl);
}

.hero-scroll-indicator {
  position: absolute;
  bottom: var(--space-8);
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-2);
  color: var(--color-text-tertiary);
  font-size: var(--text-sm);
  animation: bounce 2s infinite;
}

@keyframes bounce {
  0%,
  20%,
  50%,
  80%,
  100% {
    transform: translateX(-50%) translateY(0);
  }
  40% {
    transform: translateX(-50%) translateY(-10px);
  }
  60% {
    transform: translateX(-50%) translateY(-5px);
  }
}

@media (max-width: 1024px) {
  .hero-content {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .hero-image {
    margin: 0 auto var(--space-8);
    order: -1;
  }

  .hero-cta {
    justify-content: center;
  }

  .hero-title {
    font-size: var(--text-4xl);
  }
}

@media (max-width: 640px) {
  .hero-title {
    font-size: var(--text-3xl);
  }

  .hero-image {
    width: 200px;
    height: 200px;
  }
}

/* ============================================================================= 
   12. Section Headers
   ============================================================================= */

.section-header {
  text-align: center;
  margin-bottom: var(--space-12);
}

.section-header .heading-section {
  margin-bottom: var(--space-4);
}

.section-header .text-lead {
  max-width: 600px;
  margin: 0 auto;
}

/* ============================================================================= 
   13. Contact Section
   ============================================================================= */

.contact-section {
  background: linear-gradient(
    135deg,
    var(--color-primary) 0%,
    var(--color-primary-light) 100%
  );
}

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

.contact-title {
  font-size: var(--text-3xl);
  font-weight: var(--font-bold);
  color: var(--color-text-inverse);
  margin-bottom: var(--space-4);
}

.contact-description {
  font-size: var(--text-lg);
  color: var(--color-text-tertiary);
  margin-bottom: var(--space-8);
}

.contact-cta {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-4);
  margin-bottom: var(--space-8);
}

.contact-info {
  display: flex;
  flex-wrap: wrap;
  margin-top: var(--space-4);
  justify-content: center;
  gap: var(--space-6);
  padding-top: var(--space-6);
  border-top: 1px solid var(--color-border-dark);
}

.contact-link {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  color: var(--color-text-tertiary);
  font-size: var(--text-sm);
  transition: color var(--transition-fast);
}

.contact-link:hover {
  color: var(--color-accent);
}

.social-links {
  display: flex;
  gap: var(--space-4);
}

.social-link {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  background-color: var(--color-surface-dark);
  color: var(--color-text-tertiary);
  font-size: var(--text-xl);
  transition: all var(--transition-fast);
}

.social-link:hover {
  background-color: var(--color-secondary);
  color: var(--color-surface-white);
  transform: translateY(-2px);
}

/* ============================================================================= 
   14. Animations
   ============================================================================= */

.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition:
    opacity 0.6s ease,
    transform 0.6s ease;
}

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

.stagger-1 {
  transition-delay: 0.1s;
}
.stagger-2 {
  transition-delay: 0.2s;
}
.stagger-3 {
  transition-delay: 0.3s;
}
.stagger-4 {
  transition-delay: 0.4s;
}

/* Count-up animation placeholder - JS handles actual counting */
.count-up {
  font-variant-numeric: tabular-nums;
}

/* ============================================================================= 
   15. Utility Classes
   ============================================================================= */

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

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

.mt-4 {
  margin-top: var(--space-4);
}
.mt-6 {
  margin-top: var(--space-6);
}
.mt-8 {
  margin-top: var(--space-8);
}
.mb-4 {
  margin-bottom: var(--space-4);
}
.mb-6 {
  margin-bottom: var(--space-6);
}
.mb-8 {
  margin-bottom: var(--space-8);
}

/* ============================================================================= 
   16. Navigation (Minimal)
   ============================================================================= */

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: var(--space-4) 0;
  background-color: transparent;
  transition: background-color var(--transition-base);
}

.nav.scrolled {
  background-color: rgba(10, 22, 40, 0.95);
  backdrop-filter: blur(10px);
  box-shadow: var(--shadow-md);
}

.nav-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav-logo {
  font-size: var(--text-2xl);
  font-weight: var(--font-bold);
  color: var(--color-text-inverse);
  letter-spacing: -0.02em;
  position: relative;
  display: inline-block;
}

/* Remove the old ::before approach */
.nav-logo::before {
  display: none;
}

.nav-logo span.logo-m {
  opacity: 1;
}

/* Span-based logo with ligature effect */
.logo-text {
  display: inline-flex;
  align-items: center;
  letter-spacing: 0;
}

/* M letter - clip with angle so right/middle is shorter than left */
.logo-text .logo-m {
  display: inline-block;
  clip-path: polygon(0 0, 63% 0, 73% 100%, 0 100%);
  margin-right: -8px;
}

/* S letter - positioned to connect with M's right leg */
.logo-text .logo-s {
  display: inline-block;
}

.nav-links {
  display: flex;
  gap: var(--space-6);
  list-style: none;
}

.nav-link {
  color: var(--color-text-tertiary);
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  transition: color var(--transition-fast);
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-text-inverse);
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--color-text-inverse);
  font-size: var(--text-2xl);
  cursor: pointer;
}

@media (max-width: 768px) {
  .nav-links {
    position: fixed;
    top: 60px;
    left: 0;
    right: 0;
    flex-direction: column;
    background-color: var(--color-primary);
    padding: var(--space-6);
    gap: var(--space-4);
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
  }

  .nav-links.open {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

  .nav-toggle {
    display: block;
  }
}

/* =============================================================================
   17. Project Page
   ============================================================================= */

.project-page {
  padding-top: 80px; /* Account for fixed nav */
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  color: var(--color-secondary);
  margin-bottom: var(--space-6);
  transition: gap var(--transition-fast);
}

.back-link:hover {
  gap: var(--space-3);
  color: var(--color-accent);
}

.project-header {
  margin-bottom: var(--space-10);
}

.project-title {
  font-size: var(--text-4xl);
  font-weight: var(--font-bold);
  color: var(--color-text-primary);
  margin-bottom: var(--space-4);
}

.project-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-4);
  margin-bottom: var(--space-6);
}

.project-meta-item {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
}

.project-meta-item i {
  color: var(--color-secondary);
}

.project-meta-badge {
  padding: var(--space-1) var(--space-3);
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  background-color: var(--color-surface-light);
  border-radius: var(--radius-md);
  color: var(--color-text-primary);
}

.project-intro {
  font-size: var(--text-lg);
  color: var(--color-text-secondary);
  max-width: 800px;
}

/* Project Content Grid */
.project-content {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: var(--space-12);
  align-items: start;
}

@media (max-width: 1024px) {
  .project-content {
    grid-template-columns: 1fr;
    gap: var(--space-8);
  }
}

/* Project Gallery */
.project-gallery {
  position: relative;
  border-radius: var(--radius-lg);
  overflow: hidden;
  background-color: var(--color-surface-light);
}

.project-gallery-main {
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  display: block;
}

.project-gallery-nav {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background-color: rgba(255, 255, 255, 0.9);
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-lg);
  color: var(--color-text-primary);
  transition: all var(--transition-fast);
  box-shadow: var(--shadow-md);
}

.project-gallery-nav:hover {
  background-color: var(--color-surface-white);
  transform: translateY(-50%) scale(1.1);
}

.project-gallery-prev {
  left: var(--space-4);
}

.project-gallery-next {
  right: var(--space-4);
}

.project-gallery-dots {
  display: flex;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-4);
  background-color: var(--color-surface-white);
}

.project-gallery-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--color-border);
  border: none;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.project-gallery-dot.active,
.project-gallery-dot:hover {
  background-color: var(--color-secondary);
}

/* Project Thumbnails */
.project-thumbnails {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(100px, 1fr));
  gap: var(--space-3);
  margin-top: var(--space-4);
}

.project-thumbnail {
  aspect-ratio: 16 / 10;
  border-radius: var(--radius-md);
  overflow: hidden;
  cursor: pointer;
  border: 2px solid transparent;
  transition: border-color var(--transition-fast);
}

.project-thumbnail.active,
.project-thumbnail:hover {
  border-color: var(--color-secondary);
}

.project-thumbnail img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* Project Details Sidebar */
.project-details {
  position: sticky;
  top: 100px;
}

.project-section {
  margin-bottom: var(--space-8);
}

.project-section:last-child {
  margin-bottom: 0;
}

.project-section-title {
  font-size: var(--text-lg);
  font-weight: var(--font-semibold);
  color: var(--color-text-primary);
  margin-bottom: var(--space-4);
  padding-bottom: var(--space-2);
  border-bottom: 2px solid var(--color-border);
}

.project-section-content {
  font-size: var(--text-base);
  color: var(--color-text-secondary);
  line-height: var(--leading-relaxed);
}

.project-role-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.project-role-list li {
  position: relative;
  padding-left: var(--space-5);
  margin-bottom: var(--space-3);
  color: var(--color-text-secondary);
}

.project-role-list li::before {
  content: "→";
  position: absolute;
  left: 0;
  color: var(--color-accent);
  font-weight: var(--font-bold);
}

.project-tech-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

/* Project Video Embed */
.project-video {
  margin-top: var(--space-6);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.project-video iframe {
  width: 100%;
  aspect-ratio: 16 / 9;
  border: none;
}

/* Project Live Link */
.project-live-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  color: var(--color-success);
  background-color: rgba(16, 185, 129, 0.1);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.project-live-link:hover {
  background-color: rgba(16, 185, 129, 0.2);
  color: var(--color-success);
}

/* Project page nav - solid background */
.project-page .nav {
  background-color: var(--color-primary);
}

/* =============================================================================
   18. Mobile Responsive
   ============================================================================= */

/* Tablet (768px) */
@media (max-width: 768px) {
  .section {
    padding: var(--space-12) 0;
  }

  .grid-2,
  .grid-3,
  .grid-4 {
    grid-template-columns: 1fr;
    gap: var(--space-6);
  }

  .stat-card {
    padding: var(--space-6);
  }

  .heading-section {
    font-size: var(--text-2xl);
  }

  /* Contact section - stack info vertically */
  .contact-info {
    flex-direction: column;
    gap: var(--space-3);
    align-items: center;
  }

  .contact-link {
    font-size: var(--text-xs);
    word-break: break-all;
  }

  /* Skills grid - single column on tablet */
  .skills-group {
    margin-bottom: var(--space-6);
  }

  /* Timeline adjustments */
  .timeline-role {
    font-size: var(--text-lg);
  }

  /* Project page responsive */
  .project-content {
    grid-template-columns: 1fr;
    gap: var(--space-8);
  }

  .project-details {
    position: static;
  }

  .project-title {
    font-size: var(--text-3xl);
  }

  .project-meta {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-2);
  }
}

/* Mobile (640px) */
@media (max-width: 640px) {
  .container {
    padding-left: var(--space-4);
    padding-right: var(--space-4);
  }

  .section {
    padding: var(--space-10) 0;
  }

  .heading-section {
    font-size: var(--text-xl);
  }

  .text-lead {
    font-size: var(--text-base);
  }

  /* Hero mobile tweaks */
  .hero {
    padding-top: 100px;
  }

  .hero-subtitle {
    font-size: var(--text-base);
  }

  .hero-cta {
    flex-direction: column;
    gap: var(--space-3);
  }

  .hero-cta .btn {
    width: 100%;
    justify-content: center;
  }

  /* Impact stats - 2x2 grid on mobile */
  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-4);
  }

  .stat-card {
    padding: var(--space-4);
  }

  .stat-value {
    font-size: var(--text-2xl);
  }

  .stat-suffix {
    font-size: var(--text-lg);
  }

  .stat-label {
    font-size: var(--text-xs);
  }

  /* Contact section mobile */
  .contact-title {
    font-size: var(--text-2xl);
  }

  .contact-description {
    font-size: var(--text-base);
  }

  .contact-cta {
    flex-direction: column;
    gap: var(--space-3);
  }

  .contact-cta .btn {
    width: 100%;
    justify-content: center;
  }

  /* Footer text */
  .footer .text-small,
  footer .text-small {
    font-size: var(--text-xs);
  }

  /* Skills tags wrap better */
  .skill-tag {
    font-size: var(--text-xs);
    padding: var(--space-1) var(--space-3);
  }

  /* Timeline mobile */
  .timeline-item {
    padding-left: var(--space-6);
    padding-bottom: var(--space-8);
  }

  .timeline-header {
    flex-direction: column;
    gap: var(--space-1);
  }

  .timeline-role {
    font-size: var(--text-base);
  }

  .timeline-company {
    font-size: var(--text-sm);
  }

  .timeline-achievements li {
    font-size: var(--text-sm);
  }

  /* Project page mobile */
  .project-title {
    font-size: var(--text-2xl);
  }

  .project-intro {
    font-size: var(--text-base);
  }

  .back-link {
    font-size: var(--text-xs);
  }

  .project-gallery-nav {
    width: 32px;
    height: 32px;
    font-size: var(--text-sm);
  }

  .project-thumbnails {
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-2);
  }
}

/* Small mobile (375px) */
@media (max-width: 375px) {
  .hero-title {
    font-size: var(--text-2xl);
  }

  .hero-image {
    width: 180px;
    height: 180px;
  }

  .grid-4 {
    grid-template-columns: 1fr;
  }

  .contact-link {
    font-size: 11px;
  }
}