/* ============================================
   Uliana-Olena Sakhno — Portfolio
   Theme: Light Emerald + Sand with Techy Accents
   ============================================ */

/* CSS Variables */
:root {
  /* Primary Palette */
  --emerald-900: #064e3b;
  --emerald-700: #047857;
  --emerald-600: #059669;
  --emerald-500: #10b981;
  --emerald-400: #34d399;
  --emerald-100: #d1fae5;
  --emerald-50: #ecfdf5;
  
  /* Sand / Neutral Palette */
  --sand-900: #1c1917;
  --sand-800: #292524;
  --sand-700: #44403c;
  --sand-600: #57534e;
  --sand-500: #78716c;
  --sand-400: #a8a29e;
  --sand-300: #d6d3d1;
  --sand-200: #e7e5e4;
  --sand-100: #f5f5f4;
  --sand-50: #fafaf9;
  
  /* Semantic Colors */
  --bg-primary: var(--sand-50);
  --bg-secondary: var(--sand-100);
  --bg-dark: var(--sand-900);
  --text-primary: var(--sand-800);
  --text-secondary: var(--sand-600);
  --text-muted: var(--sand-500);
  --accent: var(--emerald-600);
  --accent-light: var(--emerald-100);
  --accent-dark: var(--emerald-900);
  
  /* Typography */
  --font-sans: 'DM Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', 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: 5rem;
  --space-3xl: 8rem;
  
  /* Transitions */
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  
  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 100px;
}

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--text-primary);
  background: var(--bg-primary);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* Background Decorations */
.bg-grid {
  position: fixed;
  inset: 0;
  background-image: 
    linear-gradient(rgba(16, 185, 129, 0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(16, 185, 129, 0.03) 1px, transparent 1px);
  background-size: 60px 60px;
  pointer-events: none;
  z-index: -2;
}

.bg-glow {
  position: fixed;
  width: 600px;
  height: 600px;
  border-radius: 50%;
  filter: blur(120px);
  opacity: 0.4;
  pointer-events: none;
  z-index: -1;
}

.bg-glow--1 {
  top: -200px;
  right: -100px;
  background: var(--emerald-400);
  opacity: 0.15;
}

.bg-glow--2 {
  bottom: 20%;
  left: -200px;
  background: var(--sand-300);
  opacity: 0.3;
}

/* Container */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

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

.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(250, 250, 249, 0.8);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--sand-200);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1200px;
  margin: 0 auto;
  padding: var(--space-sm) var(--space-lg);
  height: 72px;
}

.nav__logo {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-primary);
  text-decoration: none;
  letter-spacing: -0.5px;
}

.logo-bracket {
  color: var(--accent);
}

.nav__links {
  display: flex;
  list-style: none;
  gap: var(--space-lg);
}

.nav__links a {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 500;
  transition: color var(--transition);
  position: relative;
}

.nav__links a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent);
  transition: width var(--transition);
}

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

.nav__links a:hover::after {
  width: 100%;
}

/* ============================================
   Buttons
   ============================================ */

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  padding: 0.75rem 1.5rem;
  font-family: var(--font-sans);
  font-size: 0.95rem;
  font-weight: 600;
  text-decoration: none;
  border-radius: 8px;
  cursor: pointer;
  transition: all var(--transition);
  border: 2px solid transparent;
}

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

.btn--primary:hover {
  background: var(--emerald-700);
  border-color: var(--emerald-700);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.btn--outline {
  background: transparent;
  color: var(--accent);
  border-color: var(--accent);
}

.btn--outline:hover {
  background: var(--accent);
  color: white;
}

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

.btn--ghost:hover {
  color: var(--accent);
}

.btn--large {
  padding: 1rem 2.5rem;
  font-size: 1.1rem;
}

.btn__icon {
  font-size: 0.85em;
}

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

.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding: calc(72px + var(--space-xl)) 0 var(--space-xl);
  position: relative;
}

.hero__container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-2xl);
  align-items: center;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

.hero__content {
  max-width: 560px;
}

.hero__label {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  font-family: var(--font-mono);
  font-size: 0.875rem;
  color: var(--accent);
  margin-bottom: var(--space-md);
  padding: 0.5rem 1rem;
  background: var(--accent-light);
  border-radius: 50px;
}

.status-dot {
  width: 8px;
  height: 8px;
  background: var(--accent);
  border-radius: 50%;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(1.2); }
}

.hero__title {
  font-size: clamp(2.5rem, 5vw, 3.5rem);
  font-weight: 700;
  line-height: 1.1;
  margin-bottom: var(--space-sm);
  color: var(--text-primary);
}

.text-gradient {
  background: linear-gradient(135deg, var(--emerald-600), var(--emerald-400));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero__subtitle {
  font-size: clamp(1.25rem, 3vw, 1.75rem);
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: var(--space-md);
}

.hero__subtitle em {
  font-style: normal;
  color: var(--accent);
}

.hero__description {
  font-size: 1.1rem;
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: var(--space-lg);
}

.hero__cta {
  display: flex;
  gap: var(--space-sm);
  flex-wrap: wrap;
}

/* Terminal Decoration */
.terminal {
  background: var(--sand-900);
  border-radius: 12px;
  overflow: hidden;
  box-shadow: var(--shadow-xl);
  font-family: var(--font-mono);
  font-size: 0.9rem;
}

.terminal__header {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 12px 16px;
  background: var(--sand-800);
}

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

.terminal__dot--red { background: #ff5f57; }
.terminal__dot--yellow { background: #febc2e; }
.terminal__dot--green { background: #28c840; }

.terminal__title {
  margin-left: auto;
  color: var(--sand-500);
  font-size: 0.8rem;
}

.terminal__body {
  padding: var(--space-md);
  color: var(--sand-300);
  line-height: 2;
}

.terminal__prompt {
  color: var(--emerald-400);
}

.terminal__success {
  color: var(--emerald-400);
}

.terminal__cursor {
  animation: blink 1s infinite;
}

@keyframes blink {
  0%, 50% { opacity: 1; }
  51%, 100% { opacity: 0; }
}

.hero__flag {
  position: absolute;
  top: calc(72px + var(--space-lg));
  right: var(--space-lg);
}

.hero__flag img {
  transition: transform var(--transition);
  opacity: 0.9;
}

.hero__flag:hover img {
  transform: scale(1.05);
  opacity: 1;
}

/* ============================================
   Sections
   ============================================ */

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

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

.section--contact {
  background: var(--sand-900);
  color: white;
}

.section__label {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 2px;
  margin-bottom: var(--space-sm);
}

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

.section__title {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 700;
  color: var(--text-primary);
  text-align: center;
  margin-bottom: var(--space-2xl);
}

.section--contact .section__title,
.section--contact .section__label {
  color: white;
}

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

.about {
  display: grid;
  grid-template-columns: 350px 1fr;
  gap: var(--space-2xl);
  align-items: start;
}

.about__image-wrapper {
  position: relative;
}

.about__image-wrapper img {
  width: 100%;
  border-radius: 12px;
  position: relative;
  z-index: 1;
}

.about__image-border {
  position: absolute;
  inset: 15px -15px -15px 15px;
  border: 3px solid var(--accent);
  border-radius: 12px;
  z-index: 0;
}

.about__content {
  padding-top: var(--space-md);
}

.about__title {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--space-md);
  font-style: italic;
}

.about__content p {
  color: var(--text-secondary);
  margin-bottom: var(--space-sm);
  line-height: 1.8;
}

.about__stats {
  display: flex;
  gap: var(--space-xl);
  margin-top: var(--space-lg);
  padding-top: var(--space-lg);
  border-top: 1px solid var(--sand-200);
}

.stat {
  text-align: center;
}

.stat__number {
  display: block;
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--accent);
  line-height: 1;
}

.stat__label {
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-top: var(--space-xs);
}

/* ============================================
   Skills Section
   ============================================ */

.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
}

.skill-card {
  background: white;
  padding: var(--space-lg);
  border-radius: 12px;
  border: 1px solid var(--sand-200);
  transition: all var(--transition);
}

.skill-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
  border-color: var(--accent);
}

.skill-card__icon {
  font-size: 2rem;
  margin-bottom: var(--space-sm);
}

.skill-card__title {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--space-sm);
}

.skill-card__list {
  list-style: none;
}

.skill-card__list li {
  padding: var(--space-xs) 0;
  color: var(--text-secondary);
  font-size: 0.95rem;
  position: relative;
  padding-left: 1rem;
}

.skill-card__list li::before {
  content: '▸';
  position: absolute;
  left: 0;
  color: var(--accent);
}

.skills-tags {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-xs);
}

.tag {
  padding: 0.5rem 1rem;
  background: white;
  border: 1px solid var(--sand-300);
  border-radius: 50px;
  font-size: 0.875rem;
  color: var(--text-secondary);
  transition: all var(--transition);
}

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

.tag--highlight {
  background: var(--accent-light);
  border-color: var(--accent);
  color: var(--accent-dark);
}

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

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

.timeline::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--sand-200);
}

.timeline__item {
  position: relative;
  padding-left: var(--space-xl);
  padding-bottom: var(--space-xl);
}

.timeline__item:last-child {
  padding-bottom: 0;
}

.timeline__marker {
  position: absolute;
  left: -6px;
  top: 0;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--sand-300);
  border: 3px solid var(--bg-primary);
  transition: all var(--transition);
}

.timeline__item--active .timeline__marker {
  background: var(--accent);
  box-shadow: 0 0 0 4px var(--accent-light);
}

.timeline__content {
  background: white;
  padding: var(--space-lg);
  border-radius: 12px;
  border: 1px solid var(--sand-200);
  transition: all var(--transition);
}

.timeline__item:hover .timeline__content {
  border-color: var(--accent);
  box-shadow: var(--shadow-md);
}

.timeline__header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: var(--space-sm);
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.timeline__company {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  display: block;
}

.timeline__role {
  font-size: 0.95rem;
  color: var(--accent);
  font-weight: 500;
}

.timeline__date {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text-muted);
}

.timeline__project {
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-bottom: var(--space-sm);
}

.timeline__duties {
  list-style: none;
}

.timeline__duties li {
  position: relative;
  padding-left: 1.25rem;
  padding-top: var(--space-xs);
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.6;
}

.timeline__duties li::before {
  content: '▹';
  position: absolute;
  left: 0;
  color: var(--accent);
}

/* ============================================
   Projects Grid & Cards
   ============================================ */

.projects-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-lg);
}

.project-card {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-2xl);
  align-items: center;
  background: white;
  border-radius: 16px;
  padding: var(--space-xl);
  border: 1px solid var(--sand-200);
  box-shadow: var(--shadow-lg);
}

.project-card--compact {
  grid-template-columns: 1fr;
  gap: var(--space-md);
  padding: var(--space-lg);
  transition: all var(--transition);
}

.project-card--compact:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-xl);
  border-color: var(--accent);
}

.project-card__badge {
  display: inline-block;
  padding: 0.5rem 1rem;
  background: var(--accent-light);
  color: var(--accent-dark);
  font-size: 0.85rem;
  font-weight: 600;
  border-radius: 50px;
  margin-bottom: var(--space-sm);
}

.project-card__title {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--space-sm);
}

.project-card__description,
.project-card__role {
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: var(--space-sm);
  font-size: 0.95rem;
}

.project-card__tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
  margin-bottom: var(--space-md);
}

.project-card__tags span {
  padding: 0.375rem 0.75rem;
  background: var(--sand-100);
  color: var(--text-secondary);
  font-size: 0.8rem;
  border-radius: 6px;
}

.project-card__image {
  width: 100%;
  height: 200px;
  object-fit: cover;
  border-radius: 12px;
  border: 4px solid var(--sand-900);
  box-shadow: var(--shadow-md);
}

.project-card__link {
  display: inline-flex;
  align-items: center;
  color: var(--accent);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.95rem;
  transition: color var(--transition);
}

.project-card__link:hover {
  color: var(--emerald-700);
}

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

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

.contact__title {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  margin-bottom: var(--space-md);
}

.contact__description {
  color: var(--sand-400);
  font-size: 1.1rem;
  line-height: 1.8;
  margin-bottom: var(--space-lg);
}

.section--contact .btn--primary {
  background: var(--emerald-500);
  border-color: var(--emerald-500);
}

.section--contact .btn--primary:hover {
  background: var(--emerald-400);
  border-color: var(--emerald-400);
}

.contact__links {
  display: flex;
  justify-content: center;
  gap: var(--space-lg);
  margin-top: var(--space-xl);
  flex-wrap: wrap;
}

.contact__link {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  color: var(--sand-400);
  text-decoration: none;
  font-size: 0.95rem;
  transition: color var(--transition);
}

.contact__link:hover {
  color: var(--emerald-400);
}

.contact__link-icon {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--sand-800);
  border-radius: 50%;
  font-size: 0.9rem;
  font-weight: 600;
}

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

.footer {
  background: var(--sand-900);
  color: var(--sand-500);
  text-align: center;
  padding: var(--space-lg);
  font-size: 0.875rem;
  border-top: 1px solid var(--sand-800);
}

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

@media (max-width: 1024px) {
  .hero__container {
    grid-template-columns: 1fr;
    gap: var(--space-xl);
  }
  
  .hero__content {
    max-width: 100%;
    text-align: center;
  }
  
  .hero__cta {
    justify-content: center;
  }
  
  .terminal {
    max-width: 500px;
    margin: 0 auto;
  }
  
  .about {
    grid-template-columns: 1fr;
    gap: var(--space-xl);
  }
  
  .about__image {
    max-width: 350px;
    margin: 0 auto;
  }
  
  .project-card {
    grid-template-columns: 1fr;
  }
  
  .project-card__visual {
    order: -1;
  }
  
  .projects-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  :root {
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --space-3xl: 4rem;
  }
  
  .nav__links {
    display: none;
  }
  
  .hero {
    min-height: auto;
    padding-top: calc(72px + var(--space-md));
    padding-bottom: var(--space-xl);
  }
  
  .hero__flag {
    position: absolute;
    top: calc(72px + var(--space-sm));
    right: var(--space-sm);
    left: auto;
  }
  
  .hero__flag img {
    height: 50px;
  }
  
  .hero__container {
    padding: var(--space-md);
    gap: var(--space-lg);
  }
  
  .hero__content {
    padding-top: var(--space-md);
  }
  
  .hero__label {
    font-size: 0.75rem;
    padding: 0.4rem 0.8rem;
  }
  
  .hero__title {
    font-size: 2rem;
    line-height: 1.2;
  }
  
  .hero__subtitle {
    font-size: 1.15rem;
  }
  
  .hero__description {
    font-size: 1rem;
    line-height: 1.7;
  }
  
  .hero__cta {
    flex-direction: column;
    gap: var(--space-sm);
  }
  
  .hero__cta .btn {
    width: 100%;
    justify-content: center;
  }
  
  .terminal {
    display: none;
  }
  
  .about__stats {
    flex-direction: row;
    justify-content: space-around;
    gap: var(--space-sm);
  }
  
  .stat__number {
    font-size: 1.75rem;
  }
  
  .stat__label {
    font-size: 0.75rem;
  }
  
  .timeline::before {
    left: 6px;
  }
  
  .timeline__marker {
    left: 0;
  }
  
  .timeline__item {
    padding-left: var(--space-lg);
  }
  
  .contact__links {
    flex-direction: column;
    align-items: center;
    gap: var(--space-md);
  }
}

@media (max-width: 480px) {
  .nav {
    padding: var(--space-sm);
    height: 60px;
  }
  
  .nav__logo {
    font-size: 1.25rem;
  }
  
  .hero {
    padding-top: calc(60px + var(--space-sm));
  }
  
  .hero__flag {
    top: calc(60px + var(--space-xs));
  }
  
  .hero__flag img {
    height: 40px;
  }
  
  .hero__container {
    padding: var(--space-sm);
  }
  
  .hero__label {
    font-size: 0.7rem;
  }
  
  .hero__title {
    font-size: 1.75rem;
  }
  
  .hero__subtitle {
    font-size: 1rem;
  }
  
  .hero__description {
    font-size: 0.95rem;
  }
  
  .section__title {
    font-size: 1.5rem;
  }
  
  .about__image-border {
    inset: 10px -10px -10px 10px;
  }
  
  .about__stats {
    flex-direction: column;
    gap: var(--space-sm);
  }
  
  .stat__number {
    font-size: 2rem;
  }
  
  .project-card {
    padding: var(--space-md);
  }
  
  .project-card__title {
    font-size: 1.25rem;
  }
}

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

a:focus,
button:focus {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* Selection */
::selection {
  background: var(--accent-light);
  color: var(--accent-dark);
}