/* ===========================
   Base & Reset
   =========================== */

*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 64px;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: #fafafa;
  color: #1a1a1a;
  line-height: 1.7;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  color: #2563eb;
  text-decoration: none;
  transition: color 0.2s ease;
}

a:hover {
  color: #1d4ed8;
}

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

ul {
  list-style: none;
}

/* ===========================
   Container
   =========================== */

.container {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 24px;
}

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

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(250, 250, 250, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.3s ease, box-shadow 0.3s ease;
}

.nav.scrolled {
  border-bottom-color: #e5e7eb;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
}

.nav-inner {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 24px;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-name {
  font-weight: 600;
  font-size: 1rem;
  color: #1a1a1a;
  letter-spacing: -0.01em;
}

.nav-name:hover {
  color: #2563eb;
}

.nav-links {
  display: flex;
  gap: 28px;
}

.nav-links a {
  font-size: 0.875rem;
  font-weight: 500;
  color: #6b7280;
  transition: color 0.2s ease;
}

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

/* Hamburger */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.nav-toggle span {
  display: block;
  width: 20px;
  height: 2px;
  background: #1a1a1a;
  border-radius: 1px;
  transition: transform 0.3s ease, opacity 0.3s ease;
}

.nav-toggle.open span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

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

.nav-toggle.open span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

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

.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 80px 24px 60px;
}

.hero-content {
  max-width: 520px;
}

.hero-photo {
  width: 140px;
  height: 140px;
  border-radius: 50%;
  object-fit: cover;
  margin: 0 auto 28px;
  border: 3px solid #e5e7eb;
}

.hero-name {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 8px;
  color: #1a1a1a;
}

.hero-tagline {
  font-size: 1.125rem;
  color: #6b7280;
  margin-bottom: 8px;
}

.hero-oneliner {
  font-size: 0.9375rem;
  color: #9ca3af;
  margin-bottom: 28px;
}

.hero-socials {
  display: flex;
  justify-content: center;
  gap: 16px;
  margin-bottom: 20px;
}

.hero-socials a {
  color: #6b7280;
  transition: color 0.2s ease, transform 0.2s ease;
  display: flex;
  align-items: center;
}

.hero-socials a:hover {
  color: #2563eb;
  transform: translateY(-1px);
}

.hero-cv {
  display: inline-block;
  font-size: 0.8125rem;
  font-weight: 500;
  color: #6b7280;
  border: 1px solid #d1d5db;
  padding: 6px 16px;
  border-radius: 6px;
  transition: color 0.2s ease, border-color 0.2s ease;
}

.hero-cv:hover {
  color: #2563eb;
  border-color: #2563eb;
}

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

.section {
  padding: 80px 0;
}

.section-title {
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 24px;
  color: #1a1a1a;
}

.section-intro {
  color: #4b5563;
  margin-bottom: 32px;
  font-size: 0.9375rem;
  line-height: 1.8;
}

.subsection-title {
  font-size: 1rem;
  font-weight: 600;
  color: #374151;
  margin-bottom: 16px;
  margin-top: 40px;
}

.subsection-title:first-of-type {
  margin-top: 0;
}

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

.about-text p {
  color: #374151;
  font-size: 0.9375rem;
  line-height: 1.8;
  margin-bottom: 16px;
}

.about-text p:last-child {
  margin-bottom: 0;
}

/* ===========================
   Entries (Research / Experience)
   =========================== */

.entry {
  padding: 24px 0;
  border-bottom: 1px solid #f3f4f6;
}

.entry:last-child {
  border-bottom: none;
}

.entry-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 16px;
  margin-bottom: 12px;
}

.entry-title {
  font-size: 1.0625rem;
  font-weight: 600;
  color: #1a1a1a;
}

.entry-sub {
  font-size: 0.875rem;
  color: #6b7280;
  margin-top: 2px;
}

.entry-date {
  font-size: 0.8125rem;
  color: #9ca3af;
  white-space: nowrap;
  flex-shrink: 0;
  padding-top: 3px;
}

.entry-details {
  padding-left: 18px;
  list-style: disc;
}

.entry-details li {
  font-size: 0.875rem;
  color: #4b5563;
  line-height: 1.7;
  margin-bottom: 4px;
}

.entry-details li:last-child {
  margin-bottom: 0;
}

/* ===========================
   Awards
   =========================== */

.awards-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 32px;
}

.award-item {
  display: flex;
  gap: 20px;
  align-items: baseline;
  font-size: 0.9375rem;
  color: #374151;
}

.award-date {
  font-size: 0.8125rem;
  color: #9ca3af;
  white-space: nowrap;
  min-width: 70px;
  flex-shrink: 0;
}

/* ===========================
   Project Cards
   =========================== */

.projects-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

.project-card {
  background: #fff;
  border: 1px solid #e5e7eb;
  border-radius: 10px;
  padding: 24px;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.project-card:hover {
  border-color: #d1d5db;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
}

.project-title {
  font-size: 1rem;
  font-weight: 600;
  color: #1a1a1a;
  margin-bottom: 4px;
}

.project-meta {
  font-size: 0.8125rem;
  color: #9ca3af;
  margin-bottom: 12px;
}

.project-desc {
  font-size: 0.875rem;
  color: #4b5563;
  line-height: 1.7;
  margin-bottom: 12px;
}

.project-link {
  font-size: 0.8125rem;
  font-weight: 500;
}

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

.section-contact {
  text-align: center;
  padding-bottom: 60px;
}

.contact-text {
  color: #4b5563;
  font-size: 0.9375rem;
  margin-bottom: 16px;
}

.contact-email {
  display: inline-block;
  font-size: 1.0625rem;
  font-weight: 500;
  color: #2563eb;
  margin-bottom: 24px;
}

.contact-email:hover {
  color: #1d4ed8;
}

.contact-socials {
  display: flex;
  justify-content: center;
  gap: 16px;
}

.contact-socials a {
  color: #9ca3af;
  transition: color 0.2s ease;
  display: flex;
  align-items: center;
}

.contact-socials a:hover {
  color: #2563eb;
}

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

.footer {
  text-align: center;
  padding: 24px 0;
  border-top: 1px solid #f3f4f6;
}

.footer p {
  font-size: 0.8125rem;
  color: #9ca3af;
}

/* ===========================
   Fade-in Animation
   =========================== */

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

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

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

@media (max-width: 640px) {
  .nav-toggle {
    display: flex;
  }

  .nav-links {
    position: absolute;
    top: 56px;
    left: 0;
    right: 0;
    background: #fafafa;
    flex-direction: column;
    gap: 0;
    padding: 8px 0;
    border-bottom: 1px solid #e5e7eb;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
    display: none;
  }

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

  .nav-links a {
    display: block;
    padding: 12px 24px;
    font-size: 0.9375rem;
  }

  .hero {
    min-height: auto;
    padding: 120px 24px 60px;
  }

  .hero-name {
    font-size: 1.625rem;
  }

  .hero-photo {
    width: 110px;
    height: 110px;
  }

  .section {
    padding: 56px 0;
  }

  .entry-header {
    flex-direction: column;
    gap: 4px;
  }

  .entry-date {
    font-size: 0.8125rem;
  }

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

  .award-item {
    flex-direction: column;
    gap: 2px;
  }

  .award-date {
    min-width: auto;
  }
}

@media (max-width: 380px) {
  .hero-socials {
    gap: 12px;
  }

  .hero-name {
    font-size: 1.375rem;
  }
}