/* ===== Custom Properties ===== */
:root {
  --color-bg: #ffffff;
  --color-bg-alt: #f9fafb;
  --color-text: #111827;
  --color-text-secondary: #6b7280;
  --color-accent: #2563eb;
  --color-accent-hover: #1d4ed8;
  --color-border: #e5e7eb;
  --font-main: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --max-width: 1100px;
  --nav-height: 64px;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--nav-height);
}

body {
  font-family: var(--font-main);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--color-accent);
  text-decoration: none;
}

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

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

/* ===== Navigation ===== */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid transparent;
  z-index: 1000;
  transition: border-color 0.3s, box-shadow 0.3s;
}

.nav.scrolled {
  border-bottom-color: var(--color-border);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
}

.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--color-text);
  letter-spacing: -0.02em;
}

.nav-links {
  display: flex;
  gap: 32px;
  list-style: none;
}

.nav-links a {
  color: var(--color-text-secondary);
  font-size: 0.875rem;
  font-weight: 500;
  transition: color 0.2s;
}

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

/* Hamburger */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-text);
  margin: 6px 0;
  transition: transform 0.3s, opacity 0.3s;
}

.nav-toggle.active span:nth-child(1) {
  transform: translateY(8px) rotate(45deg);
}

.nav-toggle.active span:nth-child(2) {
  opacity: 0;
}

.nav-toggle.active span:nth-child(3) {
  transform: translateY(-8px) rotate(-45deg);
}

/* ===== Sections ===== */
.section {
  padding: 96px 24px;
}

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

.container {
  max-width: var(--max-width);
  margin: 0 auto;
}

.section-label {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-accent);
  margin-bottom: 12px;
}

.section-title {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 48px;
}

/* ===== Hero ===== */
.hero {
  padding-top: calc(var(--nav-height) + 80px);
  padding-bottom: 96px;
  min-height: 100vh;
  display: flex;
  align-items: center;
}

.hero-content {
  max-width: 680px;
}

.hero-name {
  font-size: 3.5rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.1;
  margin-bottom: 16px;
}

.hero-title {
  font-size: 1.25rem;
  color: var(--color-accent);
  font-weight: 500;
  margin-bottom: 24px;
}

.hero-description {
  font-size: 1.125rem;
  color: var(--color-text-secondary);
  line-height: 1.7;
  margin-bottom: 40px;
  max-width: 560px;
}

.hero-buttons {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 24px;
  font-size: 0.875rem;
  font-weight: 600;
  border-radius: 8px;
  border: none;
  cursor: pointer;
  transition: all 0.2s;
  font-family: var(--font-main);
}

.btn-primary {
  background: var(--color-accent);
  color: #ffffff;
}

.btn-primary:hover {
  background: var(--color-accent-hover);
  color: #ffffff;
}

.btn-secondary {
  background: transparent;
  color: var(--color-text);
  border: 1px solid var(--color-border);
}

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

/* ===== About / Stats ===== */
.about-text {
  font-size: 1.125rem;
  color: var(--color-text-secondary);
  line-height: 1.8;
  max-width: 720px;
  margin-bottom: 48px;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}

.stat {
  text-align: center;
  padding: 32px 16px;
  border: 1px solid var(--color-border);
  border-radius: 12px;
  background: var(--color-bg);
}

.stat-number {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--color-accent);
  letter-spacing: -0.02em;
}

.stat-label {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  margin-top: 4px;
}

/* ===== Experience Timeline ===== */
.timeline {
  position: relative;
  padding-left: 32px;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 7px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: var(--color-border);
}

.timeline-item {
  position: relative;
  padding-bottom: 48px;
}

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

.timeline-item::before {
  content: '';
  position: absolute;
  left: -32px;
  top: 8px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--color-bg);
  border: 3px solid var(--color-accent);
  z-index: 1;
}

.timeline-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 4px;
}

.timeline-role {
  font-size: 1.125rem;
  font-weight: 700;
}

.timeline-date {
  font-size: 0.8125rem;
  color: var(--color-text-secondary);
  font-weight: 500;
  white-space: nowrap;
}

.timeline-company {
  font-size: 0.9375rem;
  color: var(--color-accent);
  font-weight: 500;
  margin-bottom: 12px;
}

.timeline-bullets {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.timeline-bullets li {
  position: relative;
  padding-left: 16px;
  font-size: 0.9375rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
}

.timeline-bullets li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 10px;
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--color-text-secondary);
}

.education {
  margin-top: 48px;
  padding-top: 48px;
  border-top: 1px solid var(--color-border);
}

.education-title {
  font-size: 1.125rem;
  font-weight: 700;
  margin-bottom: 16px;
}

.education-item {
  margin-bottom: 8px;
  font-size: 0.9375rem;
  color: var(--color-text-secondary);
}

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

/* ===== Projects Cards ===== */
.projects-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
}

.project-card {
  border: 1px solid var(--color-border);
  border-radius: 12px;
  padding: 36px;
  background: var(--color-bg);
  transition: box-shadow 0.3s;
}

.project-card:hover {
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.06);
}

.project-header {
  margin-bottom: 16px;
}

.project-name {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 4px;
}

.project-role {
  font-size: 0.875rem;
  color: var(--color-accent);
  font-weight: 500;
}

.project-description {
  font-size: 0.9375rem;
  color: var(--color-text-secondary);
  line-height: 1.7;
  margin-bottom: 20px;
}

.project-metrics {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 20px;
}

.metric {
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--color-text);
  background: var(--color-bg-alt);
  padding: 6px 14px;
  border-radius: 6px;
  border: 1px solid var(--color-border);
}

.project-tech {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tech-tag {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--color-accent);
  background: rgba(37, 99, 235, 0.08);
  padding: 4px 10px;
  border-radius: 4px;
}

/* ===== Skills Grid ===== */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}

.skill-category h3 {
  font-size: 0.875rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 16px;
  color: var(--color-text);
}

.skill-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.skill-pill {
  font-size: 0.8125rem;
  color: var(--color-text-secondary);
  background: var(--color-bg-alt);
  padding: 6px 12px;
  border-radius: 6px;
  border: 1px solid var(--color-border);
}

/* ===== Contact / Footer ===== */
.footer {
  text-align: center;
  padding: 64px 24px;
  border-top: 1px solid var(--color-border);
}

.footer-title {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 24px;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 32px;
  flex-wrap: wrap;
  margin-bottom: 16px;
}

.footer-links a {
  font-size: 0.9375rem;
  color: var(--color-text-secondary);
  transition: color 0.2s;
}

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

.footer-location {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
}

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

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

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .nav-links {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--color-bg);
    flex-direction: column;
    gap: 0;
    border-bottom: 1px solid var(--color-border);
    display: none;
  }

  .nav-links.open {
    display: flex;
  }

  .nav-links li {
    border-top: 1px solid var(--color-border);
  }

  .nav-links a {
    display: block;
    padding: 16px 24px;
    font-size: 1rem;
  }

  .nav-toggle {
    display: block;
  }

  .hero {
    padding-top: calc(var(--nav-height) + 48px);
    min-height: auto;
    padding-bottom: 64px;
  }

  .hero-name {
    font-size: 2.25rem;
  }

  .hero-description {
    font-size: 1rem;
  }

  .section {
    padding: 64px 20px;
  }

  .section-title {
    font-size: 1.5rem;
    margin-bottom: 32px;
  }

  .stats-grid {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .stat {
    padding: 24px 16px;
  }

  .stat-number {
    font-size: 1.75rem;
  }

  .timeline {
    padding-left: 24px;
  }

  .timeline-item::before {
    left: -24px;
    width: 12px;
    height: 12px;
  }

  .timeline-header {
    flex-direction: column;
    gap: 2px;
  }

  .project-card {
    padding: 24px;
  }

  .skills-grid {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .footer-links {
    flex-direction: column;
    gap: 16px;
  }
}

@media (min-width: 769px) and (max-width: 1024px) {
  .stats-grid {
    grid-template-columns: repeat(3, 1fr);
  }

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