:root {
  --bg: #f5f7fb;
  --surface: #ffffff;
  --surface-soft: #f9fafc;
  --text: #1f2937;
  --muted: #6b7280;
  --border: #e5e7eb;
  --primary: #1d4ed8;
  --primary-soft: #dbeafe;
  --shadow: 0 12px 28px rgba(15, 23, 42, 0.08);
  --radius: 14px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "Inter", "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

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

a:hover {
  text-decoration: underline;
}

.container {
  width: min(1100px, 92%);
  margin: 0 auto;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 40;
  backdrop-filter: blur(8px);
  background: rgba(245, 247, 251, 0.9);
  border-bottom: 1px solid var(--border);
}

.topbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 14px 0;
}

.brand {
  font-weight: 700;
  font-size: 1.15rem;
}

.brand a {
  color: inherit;
  text-decoration: none;
}

.brand span {
  display: block;
  font-weight: 500;
  color: var(--muted);
  font-size: 0.82rem;
}

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

.nav a {
  color: #374151;
  font-size: 0.93rem;
  font-weight: 600;
}

.nav a.active {
  color: var(--primary);
}

.hero {
  padding: 24px 0 18px;
}

.page-hero {
  padding: 42px 0 8px;
}

.page-hero .card h1 {
  font-size: clamp(1.5rem, 3vw, 2rem);
}

.page-hero .card p {
  margin: 8px 0 0;
  color: #374151;
}

.hero-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 32px;
  display: grid;
  grid-template-columns: minmax(320px, 36%) 1fr;
  gap: 28px;
  align-items: center;
}

.hero img {
  width: 100%;
  height: 420px;
  object-fit: cover;
  object-position: center;
  border-radius: 12px;
  border: 1px solid var(--border);
}

h1 {
  margin: 0;
  font-size: clamp(1.7rem, 3vw, 2.2rem);
}

.subtitle {
  margin-top: 4px;
  color: var(--muted);
  font-weight: 600;
}

.hero p {
  margin: 14px 0 0;
  color: #374151;
}

.cta-row {
  margin-top: 22px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 16px;
  border-radius: 10px;
  border: 1px solid var(--border);
  font-weight: 600;
  font-size: 0.92rem;
  text-decoration: none;
  color: #111827;
  background: #fff;
}

.btn.primary {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}

.section {
  padding: 18px 0 10px;
}

.section-header {
  margin: 18px 0 14px;
}

.section-header h2 {
  margin: 0;
  font-size: 1.45rem;
}

.section-header p {
  margin: 4px 0 0;
  color: var(--muted);
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
}

.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.skill-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(140px, 1fr));
  gap: 10px;
}

.skill-pill {
  background: var(--surface-soft);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 8px 12px;
  font-size: 0.9rem;
  display: inline-flex;
  justify-content: space-between;
  gap: 8px;
}

.timeline {
  display: grid;
  gap: 14px;
}

.timeline-horizontal {
  position: relative;
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: minmax(240px, 1fr);
  gap: 14px;
  overflow-x: auto;
  align-items: start;
  padding-top: 18px;
  padding-bottom: 6px;
}

.timeline-horizontal::before {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  height: 2px;
  background: var(--border);
}

.timeline-horizontal .timeline-item {
  position: relative;
}

.timeline-horizontal .timeline-item::before {
  content: "";
  position: absolute;
  left: 20px;
  top: -24px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-soft);
}

.timeline-vertical {
  position: relative;
  padding-left: 28px;
}

.timeline-vertical::before {
  content: "";
  position: absolute;
  left: 10px;
  top: 6px;
  bottom: 6px;
  width: 2px;
  background: var(--border);
}

.timeline-vertical .timeline-item {
  position: relative;
}

.timeline-vertical .timeline-item::before {
  content: "";
  position: absolute;
  left: -23px;
  top: 20px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-soft);
}

.timeline-item h3 {
  margin: 0;
  font-size: 1.08rem;
}

.timeline-year {
  color: var(--primary);
  font-size: 0.86rem;
  font-weight: 700;
  margin-bottom: 6px;
}

.timeline-item .meta {
  color: var(--muted);
  font-size: 0.92rem;
  margin-bottom: 0;
}

.timeline-item ul {
  margin: 0;
  padding-left: 20px;
}

.project-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(230px, 1fr));
  gap: 14px;
}

.filter-toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 14px;
}

.filter-btn {
  border: 1px solid var(--border);
  background: #fff;
  color: #374151;
  border-radius: 999px;
  padding: 8px 12px;
  font-size: 0.88rem;
  font-weight: 600;
  cursor: pointer;
}

.filter-btn.active {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
}

.project-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px;
}

.project-thumb {
  width: 100%;
  height: 150px;
  object-fit: cover;
  border-radius: 10px;
  border: 1px solid var(--border);
  margin-bottom: 10px;
}

.project-card h3 {
  margin: 0;
  font-size: 1.02rem;
}

.project-card p {
  margin: 8px 0 12px;
  color: #374151;
  font-size: 0.93rem;
}

.project-points {
  margin: 8px 0 12px;
  padding-left: 18px;
  color: #374151;
  font-size: 0.92rem;
}

.project-points li {
  margin-bottom: 6px;
}

.about-thesis-image {
  width: 100%;
  height: 100%;
  min-height: 320px;
  object-fit: cover;
  object-position: center;
  border-radius: 12px;
  border: 1px solid var(--border);
}

.about-intro {
  display: grid;
  grid-template-columns: 1fr minmax(280px, 36%);
  gap: 18px;
  align-items: center;
}

.about-thesis-card {
  padding: 12px;
  display: flex;
}

.about-academic-card p {
  text-align: justify;
}

.about-gallery {
  margin-top: 14px;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
}

.about-gallery-image {
  width: 100%;
  height: 180px;
  object-fit: cover;
  object-position: center;
  border-radius: 10px;
  border: 1px solid var(--border);
}

.about-gallery-image-portrait {
  object-fit: cover;
  object-position: center 22%;
}

.project-card.hidden {
  display: none;
}

.tag {
  display: inline-block;
  margin-bottom: 8px;
  font-size: 0.78rem;
  color: #1e3a8a;
  background: var(--primary-soft);
  padding: 3px 8px;
  border-radius: 999px;
  font-weight: 600;
}

.publication-list {
  display: grid;
  gap: 12px;
}

.publication-item h3 {
  margin: 0;
  font-size: 1.03rem;
}

.publication-item p {
  margin: 6px 0 0;
  color: #374151;
}

.contact-card {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.contact-icons {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  justify-content: center;
  align-items: center;
}

.icon-link {
  width: 46px;
  height: 46px;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: #fff;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: #1f2937;
  transition: all 0.2s ease;
}

.icon-link:hover {
  color: #fff;
  background: var(--primary);
  border-color: var(--primary);
  text-decoration: none;
}

.icon-link svg {
  width: 20px;
  height: 20px;
  fill: currentColor;
}

.footer {
  text-align: center;
  color: var(--muted);
  padding: 34px 0 44px;
  font-size: 0.9rem;
}

@media (max-width: 960px) {
  .hero-card {
    grid-template-columns: 1fr;
  }

  .project-grid {
    grid-template-columns: repeat(2, minmax(220px, 1fr));
  }

  .skill-grid {
    grid-template-columns: repeat(2, minmax(140px, 1fr));
  }

  .two-col {
    grid-template-columns: 1fr;
  }

  .about-intro {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 620px) {
  .topbar-inner {
    flex-direction: column;
    align-items: flex-start;
  }

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

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

  .hero-card {
    padding: 22px;
  }

  .about-thesis-image {
    height: 220px;
  }

  .about-gallery {
    grid-template-columns: 1fr;
  }

  .about-gallery-image {
    height: 220px;
  }

  .timeline-horizontal {
    grid-auto-columns: minmax(230px, 260px);
    padding-top: 18px;
  }

  .timeline-horizontal::before {
    top: 0;
  }
}