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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 5rem;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    Helvetica, Arial, sans-serif;
  color: #2d2d2d;
  background-color: #f7f7f7;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a {
  color: #2d2d2d;
  text-decoration: none;
  transition: color 0.2s;
}

a:hover {
  color: #64748b;
}

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

/* ===== Layout ===== */
.container {
  max-width: 820px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

section {
  padding: 5rem 0;
}

/* Alternating section backgrounds */
.section-light {
  background-color: #f7f7f7;
}

.section-white {
  background-color: #fff;
}

.section-muted {
  background-color: #f0f0f0;
}

/* ===== Navigation ===== */
nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid #e0e0e0;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
  z-index: 100;
}

nav .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 4rem;
}

nav .logo {
  font-weight: 700;
  font-size: 1.1rem;
  letter-spacing: -0.02em;
  color: #1a1a1a;
}

nav .nav-links {
  display: flex;
  gap: 2rem;
  list-style: none;
}

nav .nav-links a {
  font-size: 0.875rem;
  color: #717171;
  transition: color 0.2s;
  position: relative;
}

nav .nav-links a:hover {
  color: #1a1a1a;
}

nav .nav-links a::after {
  content: "";
  position: absolute;
  bottom: -2px;
  left: 0;
  right: 0;
  height: 1px;
  background: #1a1a1a;
  transform: scaleX(0);
  transition: transform 0.2s;
}

nav .nav-links a:hover::after {
  transform: scaleX(1);
}

.menu-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
}

.menu-toggle span {
  display: block;
  width: 20px;
  height: 2px;
  background: #1a1a1a;
  margin: 4px 0;
  transition: transform 0.2s, opacity 0.2s;
}

/* ===== Hero / About ===== */
.hero {
  padding-top: 8rem;
  padding-bottom: 5rem;
  background: linear-gradient(180deg, #fff 0%, #f7f7f7 100%);
}

.hero h1 {
  font-size: 2.75rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin-bottom: 1rem;
  color: #1a1a1a;
}

.hero .tagline {
  font-size: 1.25rem;
  color: #64748b;
  margin-bottom: 2rem;
  max-width: 550px;
  font-weight: 400;
}

.hero .bio {
  font-size: 1rem;
  color: #525252;
  max-width: 600px;
  line-height: 1.75;
}

/* ===== Section Headings ===== */
.section-title {
  font-size: 1.5rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  margin-bottom: 2.5rem;
  color: #1a1a1a;
  position: relative;
  padding-bottom: 0.75rem;
}

.section-title::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 2.5rem;
  height: 2px;
  background: #a0a0a0;
  border-radius: 1px;
}

/* ===== Experience ===== */
.timeline {
  list-style: none;
}

.timeline-item {
  position: relative;
  padding-left: 1.75rem;
  padding-bottom: 2.5rem;
  border-left: 2px solid #d4d4d4;
}

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

.timeline-item::before {
  content: "";
  position: absolute;
  left: -5px;
  top: 0.45rem;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #888;
  border: 2px solid #f7f7f7;
}

.timeline-item:first-child::before {
  background: #4a4a4a;
  width: 10px;
  height: 10px;
  left: -6px;
}

.timeline-item .role {
  font-weight: 600;
  font-size: 1.05rem;
  margin-bottom: 0.15rem;
  color: #1a1a1a;
}

.timeline-item .company {
  font-size: 0.95rem;
  color: #64748b;
  margin-bottom: 0.15rem;
}

.timeline-item .dates {
  font-size: 0.825rem;
  color: #a0a0a0;
  margin-bottom: 0.75rem;
  letter-spacing: 0.02em;
}

.timeline-item .description {
  font-size: 0.925rem;
  color: #525252;
  line-height: 1.7;
}

/* ===== Skills ===== */
.skills-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 0.625rem;
}

.skill-tag {
  padding: 0.45rem 1rem;
  background: #e8e8e8;
  border: 1px solid #d4d4d4;
  border-radius: 2rem;
  font-size: 0.85rem;
  color: #3a3a3a;
  transition: background 0.2s, border-color 0.2s, transform 0.15s;
  cursor: default;
}

.skill-tag:hover {
  background: #d4d4d4;
  border-color: #b0b0b0;
  transform: translateY(-1px);
}

/* ===== Projects ===== */
.projects-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
}

.project-card {
  padding: 1.75rem;
  background: #fff;
  border: 1px solid #e0e0e0;
  border-radius: 10px;
  transition: border-color 0.2s, box-shadow 0.25s, transform 0.2s;
}

.project-card:hover {
  border-color: #c0c0c0;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.06);
  transform: translateY(-2px);
}

.project-card h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: #1a1a1a;
}

.project-card p {
  font-size: 0.925rem;
  color: #606060;
  line-height: 1.65;
  margin-bottom: 1rem;
}

.project-card .project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.project-card .project-tag {
  font-size: 0.75rem;
  padding: 0.2rem 0.65rem;
  background: #f0f0f0;
  border-radius: 4px;
  color: #6b6b6b;
  border: 1px solid #e5e5e5;
}

.project-card .project-link {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  margin-top: 0.75rem;
  font-size: 0.875rem;
  color: #4a4a4a;
  font-weight: 500;
  border-bottom: 1px solid #c0c0c0;
  padding-bottom: 1px;
  transition: border-color 0.2s, color 0.2s;
}

.project-card .project-link:hover {
  border-color: #4a4a4a;
  color: #1a1a1a;
}

.project-card .project-link::after {
  content: "\2192";
  font-size: 0.9rem;
  transition: transform 0.2s;
}

.project-card .project-link:hover::after {
  transform: translateX(3px);
}

.project-card .project-confidential {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  margin-top: 0.75rem;
  font-size: 0.8rem;
  color: #a0a0a0;
  font-style: italic;
  letter-spacing: 0.01em;
}

/* ===== Contact ===== */
.contact-links {
  display: flex;
  gap: 1.5rem;
}

.contact-link {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 0.95rem;
  color: #4a4a4a;
  padding: 0.65rem 1.25rem;
  border-radius: 8px;
  background: #fff;
  border: 1px solid #e0e0e0;
  transition: background 0.2s, border-color 0.2s, box-shadow 0.2s, color 0.2s;
}

.contact-link:hover {
  color: #1a1a1a;
  background: #f5f5f5;
  border-color: #c0c0c0;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
}

.contact-link svg {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
  color: #888;
  transition: color 0.2s;
}

.contact-link:hover svg {
  color: #4a4a4a;
}

/* ===== Footer ===== */
footer {
  padding: 2.5rem 0;
  background-color: #e8e8e8;
  border-top: 1px solid #d4d4d4;
}

footer p {
  font-size: 0.8rem;
  color: #888;
}

/* ===== Responsive ===== */
@media (max-width: 640px) {
  .hero h1 {
    font-size: 2rem;
  }

  .hero .tagline {
    font-size: 1.1rem;
  }

  section {
    padding: 3.5rem 0;
  }

  nav .nav-links {
    display: none;
    position: absolute;
    top: 4rem;
    left: 0;
    right: 0;
    flex-direction: column;
    background: rgba(255, 255, 255, 0.98);
    border-bottom: 1px solid #e0e0e0;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.06);
    padding: 1rem 1.5rem;
    gap: 1rem;
  }

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

  .menu-toggle {
    display: block;
  }

  .contact-links {
    flex-direction: column;
    gap: 0.75rem;
  }

  .projects-grid {
    gap: 1rem;
  }

  .project-card {
    padding: 1.25rem;
  }
}