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

:root {
  --blue:    #2563EB;
  --blue-lt: #EFF6FF;
  --orange:  #F97316;
  --dark:    #111827;
  --mid:     #6B7280;
  --light:   #F9FAFB;
  --border:  #E5E7EB;
  --white:   #FFFFFF;
  --radius:  12px;
  --shadow:  0 4px 24px rgba(0,0,0,0.07);
  --transition: 0.25s ease;
}

html { scroll-behavior: smooth; font-size: 16px; }

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--white);
  color: var(--dark);
  line-height: 1.6;
}

a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; }

/* ===== UTILITY ===== */
.container { max-width: 1100px; margin: 0 auto; padding: 0 24px; }
.section    { padding: 96px 0; }
.section-alt { background: var(--light); }

.section-label {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--blue);
  margin-bottom: 10px;
}

.section-title {
  font-size: clamp(1.75rem, 3vw, 2.25rem);
  font-weight: 700;
  color: var(--dark);
  margin-bottom: 48px;
}

.tag {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 600;
  padding: 3px 10px;
  border-radius: 99px;
  background: var(--blue-lt);
  color: var(--blue);
}
.tag.orange { background: #FFF7ED; color: var(--orange); }

/* ===== FADE-IN ANIMATION ===== */
.fade-up {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.55s ease, transform 0.55s ease;
}
.fade-up.visible { opacity: 1; transform: none; }

/* ===== NAV ===== */
nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  transition: box-shadow var(--transition);
}
nav.scrolled { box-shadow: 0 2px 16px rgba(0,0,0,0.08); }

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}

.nav-logo {
  font-weight: 700;
  font-size: 1.05rem;
  letter-spacing: -0.01em;
  color: var(--dark);
}
.nav-logo span { color: var(--blue); }

.nav-links {
  display: flex;
  gap: 32px;
  list-style: none;
}
.nav-links a {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--mid);
  transition: color var(--transition);
}
.nav-links a:hover { color: var(--dark); }

.lang-toggle {
  padding: 5px 14px;
  border-radius: 99px;
  border: 1.5px solid var(--border);
  background: transparent;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--mid);
  cursor: pointer;
  transition: all var(--transition);
  letter-spacing: 0.03em;
  white-space: nowrap;
}
.lang-toggle:hover {
  border-color: var(--blue);
  color: var(--blue);
}

/* ===== HERO ===== */
#hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: 60px;
}

.hero-inner {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 64px;
  align-items: center;
}

.hero-school {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  background: var(--blue-lt);
  border: 1.5px solid #BFDBFE;
  border-radius: 999px;
  padding: 8px 18px;
  margin-bottom: 20px;
  flex-wrap: wrap;
}
.hero-school-major {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--blue);
}
.hero-school-sep {
  color: #93C5FD;
  font-weight: 400;
}
.hero-school-uni {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--dark);
}
.hero-school-year {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--white);
  background: var(--blue);
  border-radius: 999px;
  padding: 2px 10px;
}

.hero-text h1 {
  font-size: clamp(2.5rem, 5vw, 3.75rem);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.03em;
  margin-bottom: 8px;
}
.hero-text h1 .accent { color: var(--blue); }

.hero-sub {
  font-size: 1.05rem;
  color: var(--mid);
  margin: 16px 0 32px;
  max-width: 520px;
  line-height: 1.7;
}

.hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 36px;
}

.hero-cta {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: 8px;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
  border: 2px solid transparent;
}
.btn-primary {
  background: var(--blue);
  color: var(--white);
}
.btn-primary:hover { background: #1D4ED8; transform: translateY(-1px); }

.btn-secondary {
  background: transparent;
  color: var(--dark);
  border-color: var(--border);
}
.btn-secondary:hover { border-color: var(--dark); transform: translateY(-1px); }

.btn-orange {
  background: var(--orange);
  color: var(--white);
}
.btn-orange:hover { background: #EA6C00; transform: translateY(-1px); }

.hero-photo {
  width: 280px;
  height: auto;
  border-radius: 16px;
  object-fit: contain;
  border: 4px solid var(--blue-lt);
  box-shadow: 0 0 0 8px #EFF6FF, var(--shadow);
  flex-shrink: 0;
}

/* ===== ABOUT ===== */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: start;
}

.about-text p {
  color: var(--mid);
  margin-bottom: 16px;
  font-size: 0.975rem;
}

.skills-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

.skill-group h4 {
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--dark);
  margin-bottom: 10px;
}

.skill-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.chip {
  font-size: 0.78rem;
  font-weight: 500;
  padding: 4px 10px;
  border-radius: 6px;
  background: var(--border);
  color: var(--dark);
}
.chip.blue { background: var(--blue-lt); color: var(--blue); }
.chip.orange { background: #FFF7ED; color: var(--orange); }

/* ===== PROJECTS ===== */
.filter-bar {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 0;
  padding-bottom: 56px;
}

.filter-btn {
  padding: 7px 18px;
  border-radius: 99px;
  border: 1.5px solid var(--border);
  background: transparent;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--mid);
  cursor: pointer;
  transition: all var(--transition);
}
.filter-btn:hover, .filter-btn.active {
  background: var(--blue);
  border-color: var(--blue);
  color: var(--white);
}

/* ===== PROJECT ROWS ===== */
.project-row {
  padding: 72px 0;
  border-top: 1px solid var(--border);
  transition: opacity 0.3s ease;
}
.project-row.hidden { display: none; }
.project-row:last-child { border-bottom: 1px solid var(--border); }

.project-row-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 72px;
  align-items: center;
}

.project-row-alt .project-row-inner {
  direction: rtl;
}
.project-row-alt .project-row-inner > * {
  direction: ltr;
}

.proj-img-wrap {
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--light);
  aspect-ratio: 4/3;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow);
  transition: transform var(--transition), box-shadow var(--transition);
}
.proj-img-wrap:hover {
  transform: scale(1.015);
  box-shadow: 0 12px 40px rgba(0,0,0,0.12);
}
.proj-img-wrap img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: top center;
}

.proj-iframe-wrap {
  overflow: hidden;
  position: relative;
}
.proj-iframe-wrap iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 200%;
  height: 200%;
  border: none;
  transform: scale(0.5);
  transform-origin: top left;
}

.proj-placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}
.proj-big-icon { font-size: 3.5rem; }
.proj-placeholder-label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--blue);
  letter-spacing: 0.04em;
}

.proj-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: 16px;
}
.proj-year {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--mid);
  margin-left: auto;
  letter-spacing: 0.05em;
}

.project-row-text h3 {
  font-size: clamp(1.25rem, 2.5vw, 1.6rem);
  font-weight: 700;
  line-height: 1.25;
  margin-bottom: 14px;
  letter-spacing: -0.02em;
}

.project-row-text p {
  font-size: 0.925rem;
  color: var(--mid);
  line-height: 1.75;
  margin-bottom: 28px;
}

.proj-links {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  align-items: center;
}

.award-badge {
  font-size: 0.72rem;
  font-weight: 600;
  padding: 4px 10px;
  border-radius: 99px;
  background: #FFF7ED;
  color: var(--orange);
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

/* ===== EXPERIENCE ===== */
.timeline { position: relative; padding-left: 32px; }
.timeline::before {
  content: '';
  position: absolute;
  left: 7px;
  top: 6px;
  bottom: 0;
  width: 2px;
  background: var(--border);
}

.timeline-item {
  position: relative;
  margin-bottom: 40px;
}
.timeline-item::before {
  content: '';
  position: absolute;
  left: -29px;
  top: 6px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--blue);
  border: 2px solid var(--white);
  box-shadow: 0 0 0 2px var(--blue);
}
.timeline-item.orange-dot::before { background: var(--orange); box-shadow: 0 0 0 2px var(--orange); }

.timeline-date {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--mid);
  margin-bottom: 4px;
  letter-spacing: 0.04em;
}

.timeline-item h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 2px;
}

.timeline-item .org {
  font-size: 0.875rem;
  color: var(--blue);
  font-weight: 600;
  margin-bottom: 10px;
}

.timeline-item ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.timeline-item ul li {
  font-size: 0.875rem;
  color: var(--mid);
  padding-left: 14px;
  position: relative;
}
.timeline-item ul li::before {
  content: '–';
  position: absolute;
  left: 0;
  color: var(--blue);
}

/* ===== RECOGNITION ===== */
.recognition-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}

.recog-card {
  background: var(--white);
  border: 1.5px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  transition: all var(--transition);
}
.recog-card:hover { border-color: var(--orange); box-shadow: var(--shadow); }

.recog-icon {
  font-size: 1.75rem;
  margin-bottom: 14px;
}

.recog-card h3 {
  font-size: 0.975rem;
  font-weight: 700;
  margin-bottom: 6px;
  line-height: 1.35;
}

.recog-card p {
  font-size: 0.83rem;
  color: var(--mid);
}

.recog-card .date {
  display: inline-block;
  margin-top: 12px;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--orange);
  letter-spacing: 0.06em;
}

/* ===== CONTACT ===== */
.contact-inner {
  text-align: center;
  max-width: 560px;
  margin: 0 auto;
}

.contact-inner p {
  color: var(--mid);
  margin-bottom: 36px;
  font-size: 0.975rem;
}

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

.contact-link {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 12px 22px;
  border-radius: 8px;
  border: 1.5px solid var(--border);
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--dark);
  transition: all var(--transition);
}
.contact-link:hover {
  border-color: var(--blue);
  color: var(--blue);
  transform: translateY(-2px);
}

/* ===== FOOTER ===== */
footer {
  text-align: center;
  padding: 28px 24px;
  font-size: 0.8rem;
  color: var(--mid);
  border-top: 1px solid var(--border);
}

/* ===== RESPONSIVE ===== */
@media (max-width: 900px) {
  .hero-inner { grid-template-columns: 1fr; text-align: center; gap: 40px; }
  .hero-photo { width: 200px; height: auto; margin: 0 auto; }
  .hero-tags, .hero-cta { justify-content: center; }
  .about-grid { grid-template-columns: 1fr; gap: 40px; }
  .recognition-grid { grid-template-columns: 1fr; }
  .project-row-inner { grid-template-columns: 1fr; gap: 32px; }
  .project-row-alt .project-row-inner { direction: ltr; }
  .proj-year { margin-left: 0; }
}

@media (max-width: 600px) {
  .section { padding: 64px 0; }
  .project-row { padding: 48px 0; }
  .skills-grid { grid-template-columns: 1fr; }
  .nav-links { display: none; }
}