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

:root {
  --accent: #6366F1;
  --accent-light: #EEF2FF;
  --text: #111827;
  --text-sub: #6B7280;
  --bg: #FFFFFF;
  --bg-gray: #F9FAFB;
  --border: #E5E7EB;
  --radius: 12px;
  --shadow: 0 1px 3px rgba(0,0,0,0.06), 0 4px 16px rgba(0,0,0,0.06);
}

html { scroll-behavior: smooth; }

body {
  font-family: 'Noto Sans KR', sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
}

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

.container { max-width: 900px; margin: 0 auto; padding: 0 24px; }
.bg-gray { background: var(--bg-gray); }

/* NAV */
#navbar {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  transition: box-shadow 0.3s;
}
#navbar.scrolled { box-shadow: 0 2px 12px rgba(0,0,0,0.08); }
.nav-inner {
  max-width: 900px; margin: 0 auto; padding: 0 24px;
  height: 60px; display: flex; align-items: center; justify-content: space-between;
}
.nav-logo { font-weight: 700; font-size: 1.2rem; color: var(--accent); font-family: 'Inter', sans-serif; }
.nav-links { list-style: none; display: flex; gap: 28px; }
.nav-links a { font-size: 0.9rem; color: var(--text-sub); font-weight: 500; transition: color 0.2s; }
.nav-links a:hover { color: var(--accent); text-decoration: none; }

/* HERO */
#hero {
  min-height: 100vh;
  display: flex; align-items: center; justify-content: center;
  text-align: center;
  padding: 80px 24px 60px;
  background: linear-gradient(135deg, #F0F4FF 0%, #FAFAFA 60%, #F5F3FF 100%);
}
.hero-content { max-width: 640px; }
.hero-greeting { font-size: 1.1rem; color: var(--text-sub); margin-bottom: 8px; }
.hero-name { font-size: clamp(2.4rem, 6vw, 3.8rem); font-weight: 700; line-height: 1.2; margin-bottom: 20px; }
.hero-name .accent { color: var(--accent); }
.hero-tagline { font-size: clamp(1rem, 2.5vw, 1.25rem); color: var(--text-sub); line-height: 1.6; margin-bottom: 12px; }
.hero-sub { font-size: 0.95rem; color: var(--accent); font-weight: 500; letter-spacing: 0.05em; margin-bottom: 36px; font-family: 'Inter', sans-serif; }
.hero-cta { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }

.btn-primary {
  padding: 12px 28px; border-radius: 8px;
  background: var(--accent); color: white; font-weight: 600; font-size: 0.95rem;
  transition: background 0.2s, transform 0.2s;
}
.btn-primary:hover { background: #4F46E5; transform: translateY(-2px); text-decoration: none; }

.btn-secondary {
  padding: 12px 28px; border-radius: 8px;
  border: 1.5px solid var(--accent); color: var(--accent); font-weight: 600; font-size: 0.95rem;
  transition: background 0.2s, transform 0.2s;
}
.btn-secondary:hover { background: var(--accent-light); transform: translateY(-2px); text-decoration: none; }

/* SECTIONS */
section { padding: 80px 0; }
.section-title {
  font-size: 1.75rem; font-weight: 700; margin-bottom: 40px;
  position: relative; display: inline-block;
}
.section-title::after {
  content: ''; display: block;
  width: 40px; height: 3px;
  background: var(--accent); border-radius: 2px;
  margin-top: 8px;
}

/* ABOUT */
.about-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 48px; align-items: start; }
.about-text p { color: var(--text-sub); margin-bottom: 16px; font-size: 1rem; }
.about-text strong { color: var(--text); }
.info-row { display: flex; gap: 12px; padding: 10px 0; border-bottom: 1px solid var(--border); font-size: 0.9rem; }
.info-label { color: var(--text-sub); min-width: 70px; font-weight: 500; }

/* SKILLS */
.skills-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; }
.skill-card {
  background: white; border-radius: var(--radius); padding: 24px;
  box-shadow: var(--shadow); border: 1px solid var(--border);
}
.skill-card h3 { font-size: 0.85rem; font-weight: 600; color: var(--accent); text-transform: uppercase; letter-spacing: 0.08em; margin-bottom: 16px; font-family: 'Inter', sans-serif; }

/* TAGS */
.tags { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 16px; }
.tag {
  padding: 4px 12px; border-radius: 20px; font-size: 0.8rem; font-weight: 500;
  background: var(--bg-gray); color: var(--text-sub); border: 1px solid var(--border);
}
.accent-tag { background: var(--accent-light); color: var(--accent); border-color: #C7D2FE; }

/* PROJECTS */
.project-list { display: flex; flex-direction: column; gap: 24px; }
.project-card {
  background: white; border-radius: var(--radius); padding: 28px;
  box-shadow: var(--shadow); border: 1px solid var(--border);
  transition: transform 0.2s, box-shadow 0.2s;
}
.project-card:hover { transform: translateY(-3px); box-shadow: 0 8px 24px rgba(99,102,241,0.1); }
.project-header { display: flex; justify-content: space-between; align-items: flex-start; margin-bottom: 16px; }
.project-org { font-size: 0.8rem; color: var(--text-sub); font-family: 'Inter', sans-serif; }
.project-header h3 { font-size: 1.15rem; font-weight: 700; margin: 4px 0 6px; }
.project-desc { color: var(--text-sub); font-size: 0.9rem; }
.project-link { font-size: 0.85rem; font-weight: 600; color: var(--accent); white-space: nowrap; margin-left: 16px; }
.bullets { padding-left: 20px; margin: 12px 0; }
.bullets li { font-size: 0.9rem; color: var(--text-sub); margin-bottom: 6px; }

/* RESEARCH */
.research-list { display: flex; flex-direction: column; gap: 20px; }
.research-card {
  background: white; border-radius: var(--radius); padding: 28px;
  box-shadow: var(--shadow); border: 1px solid var(--border);
}
.research-meta { display: flex; align-items: center; gap: 10px; margin-bottom: 10px; flex-wrap: wrap; }
.research-org { font-size: 0.8rem; font-weight: 600; color: var(--accent); font-family: 'Inter', sans-serif; }
.research-period { font-size: 0.8rem; color: var(--text-sub); }
.research-badge {
  font-size: 0.75rem; padding: 2px 10px; border-radius: 20px;
  background: #DCFCE7; color: #16A34A; font-weight: 600;
}
.research-card h3 { font-size: 1.05rem; font-weight: 700; margin-bottom: 6px; }
.research-venue { font-size: 0.82rem; color: var(--accent); font-weight: 500; margin-bottom: 10px; }
.research-card p { font-size: 0.9rem; color: var(--text-sub); margin-bottom: 0; }

/* AWARDS */
.awards-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.award-card {
  background: white; border-radius: var(--radius); padding: 24px;
  box-shadow: var(--shadow); border: 1px solid var(--border);
  text-align: center;
}
.award-badge {
  display: inline-block; padding: 4px 14px; border-radius: 20px;
  background: var(--accent); color: white; font-size: 0.8rem; font-weight: 700;
  margin-bottom: 14px;
}
.award-card h3 { font-size: 0.95rem; font-weight: 700; margin-bottom: 6px; line-height: 1.4; }
.award-card p { font-size: 0.85rem; color: var(--text-sub); }

/* CONTACT */
.contact-container { text-align: center; }
.contact-intro { color: var(--text-sub); margin-bottom: 36px; font-size: 1rem; }
.contact-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; max-width: 700px; margin: 0 auto; }
.contact-card {
  display: flex; flex-direction: column; gap: 6px;
  padding: 20px; border-radius: var(--radius);
  border: 1.5px solid var(--border); background: white;
  text-align: center; transition: border-color 0.2s, transform 0.2s;
}
.contact-card:hover { border-color: var(--accent); transform: translateY(-2px); text-decoration: none; }
.contact-label { font-size: 0.75rem; font-weight: 700; color: var(--accent); text-transform: uppercase; letter-spacing: 0.08em; font-family: 'Inter', sans-serif; }
.contact-card span:last-child { font-size: 0.85rem; color: var(--text-sub); }

/* FOOTER */
footer { text-align: center; padding: 32px; font-size: 0.85rem; color: var(--text-sub); border-top: 1px solid var(--border); }

/* ANIMATIONS */
.fade-in { animation: fadeInUp 0.8s ease both; }
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(24px); }
  to { opacity: 1; transform: translateY(0); }
}
.reveal { opacity: 0; transform: translateY(20px); transition: opacity 0.6s ease, transform 0.6s ease; }
.reveal.visible { opacity: 1; transform: translateY(0); }

/* RESPONSIVE */
@media (max-width: 700px) {
  .about-grid { grid-template-columns: 1fr; gap: 32px; }
  .skills-grid { grid-template-columns: 1fr; }
  .awards-grid { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
  .nav-links { display: none; }
  .project-header { flex-direction: column; gap: 8px; }
}