/* =====================
   Variables & Reset
   ===================== */
:root {
  --navy:    #0d1b2a;
  --dark:    #1a2d42;
  --blue:    #2563eb;
  --steel:   #3b82f6;
  --light:   #f1f5f9;
  --white:   #ffffff;
  --text:    #1e293b;
  --muted:   #64748b;
  --border:  #e2e8f0;
  --radius:  8px;
  --shadow:  0 4px 24px rgba(13,27,42,0.10);
  --trans:   all 0.25s ease;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

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

h1, h2, h3 {
  font-family: 'Montserrat', sans-serif;
  color: var(--navy);
}

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

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}

/* =====================
   Buttons
   ===================== */
.btn-primary {
  display: inline-block;
  background: var(--blue);
  color: var(--white);
  padding: 12px 28px;
  border-radius: var(--radius);
  font-family: 'Montserrat', sans-serif;
  font-weight: 600;
  font-size: 0.95rem;
  transition: var(--trans);
  border: 2px solid var(--blue);
}
.btn-primary:hover { background: #1d4ed8; border-color: #1d4ed8; }

.btn-outline {
  display: inline-block;
  background: transparent;
  color: var(--white);
  padding: 12px 28px;
  border-radius: var(--radius);
  font-family: 'Montserrat', sans-serif;
  font-weight: 600;
  font-size: 0.95rem;
  border: 2px solid rgba(255,255,255,0.6);
  transition: var(--trans);
}
.btn-outline:hover { background: rgba(255,255,255,0.12); border-color: var(--white); }

/* =====================
   Navigation
   ===================== */
#navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  background: rgba(255,255,255,0.97);
  border-bottom: 1px solid transparent;
  transition: var(--trans);
}
#navbar.scrolled {
  border-bottom-color: var(--border);
  box-shadow: 0 2px 16px rgba(13,27,42,0.08);
}

.nav-inner {
  max-width: 1180px;
  margin: 0 auto;
  padding: 0 24px;
  height: 68px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-family: 'Montserrat', sans-serif;
  font-weight: 700;
  font-size: 1rem;
  color: var(--navy);
  letter-spacing: -0.01em;
}
.nav-cred {
  font-weight: 400;
  color: var(--blue);
  font-size: 0.85rem;
  margin-left: 6px;
}

.nav-links {
  list-style: none;
  display: flex;
  align-items: center;
  gap: 20px;
}
.nav-links a {
  font-family: 'Montserrat', sans-serif;
  font-weight: 600;
  font-size: 0.875rem;
  color: var(--text);
  transition: var(--trans);
}
.nav-links a:hover { color: var(--blue); }

.nav-kiwix {
  background: var(--blue);
  color: var(--white) !important;
  padding: 6px 14px;
  border-radius: var(--radius);
  font-size: 0.8rem;
}
.nav-kiwix:hover { background: #1d4ed8; color: var(--white) !important; }

.nav-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  color: var(--navy);
  cursor: pointer;
}

/* =====================
   Hero
   ===================== */
.hero {
  min-height: 100vh;
  background: linear-gradient(160deg, var(--navy) 0%, var(--dark) 50%, #1e3a6e 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  text-align: center;
  padding: 100px 24px 80px;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse at 20% 50%, rgba(37,99,235,0.15) 0%, transparent 60%),
    radial-gradient(ellipse at 80% 20%, rgba(59,130,246,0.10) 0%, transparent 50%);
}

/* subtle grid texture */
.hero-overlay::after {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.03) 1px, transparent 1px);
  background-size: 40px 40px;
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 760px;
}

.hero-badge {
  display: inline-block;
  background: rgba(37,99,235,0.3);
  border: 1px solid rgba(59,130,246,0.5);
  color: #93c5fd;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.8rem;
  padding: 4px 14px;
  border-radius: 20px;
  margin-bottom: 20px;
  letter-spacing: 0.08em;
}

.hero-content h1 {
  font-size: clamp(2.2rem, 5vw, 3.8rem);
  color: var(--white);
  line-height: 1.15;
  margin-bottom: 12px;
  letter-spacing: -0.02em;
}

.hero-sub {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.95rem;
  color: #93c5fd;
  margin-bottom: 20px;
  letter-spacing: 0.04em;
}

.hero-desc {
  font-size: 1.1rem;
  color: rgba(255,255,255,0.75);
  max-width: 620px;
  margin: 0 auto 36px;
}

.hero-btns {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

/* =====================
   Section base
   ===================== */
.about, .experience, .research, .publications, .portals, .courses, .contact {
  padding: 96px 0;
}

.about { background: var(--white); }
.experience { background: var(--light); }
.research { background: var(--white); }
.publications { background: var(--light); }
.portals { background: var(--light); }
.courses { background: var(--white); }
.contact { background: var(--light); }

h2 {
  font-size: clamp(1.7rem, 3vw, 2.3rem);
  margin-bottom: 12px;
  text-align: center;
}

.section-sub {
  text-align: center;
  color: var(--muted);
  max-width: 600px;
  margin: 0 auto 52px;
  font-size: 1.05rem;
}

/* =====================
   About
   ===================== */
.about-inner {
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: 60px;
  align-items: start;
  margin-bottom: 48px;
}

.about-text p {
  color: var(--muted);
  margin-bottom: 16px;
  font-size: 1.02rem;
}

.about-stats-card {
  background: var(--light);
  border-radius: 12px;
  padding: 32px 28px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}

.stat-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}

.stat-num {
  font-family: 'Montserrat', sans-serif;
  font-weight: 700;
  font-size: 1.5rem;
  color: var(--blue);
  line-height: 1.1;
}

.stat-label {
  font-size: 0.75rem;
  color: var(--muted);
  margin-top: 4px;
}

.skills-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 8px;
}

.skill-tag {
  background: var(--light);
  border: 1px solid var(--border);
  color: var(--text);
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.8rem;
  padding: 5px 12px;
  border-radius: 4px;
  transition: var(--trans);
}
.skill-tag:hover {
  background: var(--blue);
  color: var(--white);
  border-color: var(--blue);
}

/* =====================
   Timeline / Experience
   ===================== */
.timeline {
  position: relative;
  padding-left: 32px;
}
.timeline::before {
  content: '';
  position: absolute;
  left: 7px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: var(--border);
}

.timeline-item {
  position: relative;
  margin-bottom: 32px;
}

.timeline-dot {
  position: absolute;
  left: -28px;
  top: 20px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--blue);
  border: 3px solid var(--light);
  box-shadow: 0 0 0 2px var(--blue);
}

.timeline-card {
  background: var(--white);
  border-radius: var(--radius);
  padding: 24px 28px;
  border: 1px solid var(--border);
  transition: var(--trans);
}
.timeline-card:hover {
  box-shadow: var(--shadow);
  border-color: #bfdbfe;
}

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

.job-header h3 {
  font-size: 1.05rem;
  color: var(--navy);
  margin-bottom: 2px;
}

.org {
  display: block;
  font-size: 0.88rem;
  color: var(--blue);
  font-weight: 600;
}

.date {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.78rem;
  color: var(--muted);
  white-space: nowrap;
  padding-top: 4px;
}

.timeline-card > p {
  color: var(--muted);
  font-size: 0.93rem;
  margin-bottom: 14px;
}

.job-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.job-tags span {
  background: #eff6ff;
  color: var(--blue);
  font-size: 0.75rem;
  font-family: 'JetBrains Mono', monospace;
  padding: 3px 10px;
  border-radius: 4px;
}

/* =====================
   Research Focus
   ===================== */
.focus-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.focus-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 26px 28px;
  transition: var(--trans);
}
.focus-card:hover {
  box-shadow: var(--shadow);
  border-color: #bfdbfe;
  transform: translateY(-2px);
}

.focus-kicker {
  display: inline-block;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.72rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--blue);
  background: #eff6ff;
  padding: 3px 10px;
  border-radius: 4px;
  margin-bottom: 14px;
}

.focus-card h3 {
  font-size: 1.05rem;
  margin-bottom: 10px;
}

.focus-card p {
  color: var(--muted);
  font-size: 0.93rem;
  margin-bottom: 16px;
}

.focus-card ul {
  list-style: none;
  display: grid;
  gap: 8px;
}

.focus-card li {
  position: relative;
  color: var(--text);
  font-size: 0.86rem;
  padding-left: 18px;
}
.focus-card li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.72em;
  width: 7px;
  height: 2px;
  background: var(--blue);
}

/* =====================
   Publications
   ===================== */
.pub-timeline {
  position: relative;
  padding-left: 32px;
}
.pub-timeline::before {
  content: '';
  position: absolute;
  left: 7px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: var(--border);
}

.pub-category-label {
  position: relative;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.78rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--blue);
  background: #dbeafe;
  display: inline-block;
  padding: 3px 12px;
  border-radius: 4px;
  margin-bottom: 16px;
  margin-top: 8px;
  margin-left: -32px;
  z-index: 1;
}

/* =====================
   Portals / Services
   ===================== */
.portals-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
}

.portal-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 36px 32px;
  transition: var(--trans);
  display: block;
}
.portal-card:hover {
  box-shadow: var(--shadow);
  border-color: #bfdbfe;
  transform: translateY(-3px);
}

.portal-icon {
  font-size: 2rem;
  margin-bottom: 14px;
}

.portal-card h3 {
  font-size: 1.1rem;
  margin-bottom: 8px;
}

.portal-card p {
  color: var(--muted);
  font-size: 0.93rem;
  margin-bottom: 16px;
}

.portal-link {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.8rem;
  color: var(--blue);
}

/* =====================
   Contact
   ===================== */
.contact-links {
  display: flex;
  flex-direction: column;
  gap: 20px;
  max-width: 520px;
  margin: 0 auto;
}

.contact-card {
  display: flex;
  gap: 18px;
  align-items: flex-start;
  background: var(--light);
  border-radius: var(--radius);
  padding: 20px 24px;
  transition: var(--trans);
  border: 1px solid transparent;
}
.contact-card:hover { border-color: #bfdbfe; background: #eff6ff; }

.contact-icon { font-size: 1.6rem; flex-shrink: 0; }

.contact-card strong {
  display: block;
  font-family: 'Montserrat', sans-serif;
  font-size: 0.95rem;
  color: var(--navy);
  margin-bottom: 2px;
}

.contact-card p {
  color: var(--muted);
  font-size: 0.9rem;
}

/* =====================
   Courses Section (index)
   ===================== */
.course-group { margin-bottom: 52px; }

.course-group-label {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.78rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--blue);
  background: #dbeafe;
  display: inline-block;
  padding: 3px 12px;
  border-radius: 4px;
  margin-bottom: 20px;
}

.courses-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 16px;
}

.course-card {
  display: block;
  background: var(--light);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px 24px;
  transition: var(--trans);
  position: relative;
  text-decoration: none;
  color: inherit;
}
.course-card:hover {
  box-shadow: var(--shadow);
  transform: translateY(-2px);
  border-color: #bfdbfe;
  background: var(--white);
}

.course-card-code {
  display: block;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.78rem;
  margin-bottom: 6px;
}
.course-card--grad .course-card-code { color: #7c3aed; }
.course-card--upper .course-card-code { color: #0369a1; }
.course-card--lower .course-card-code { color: #047857; }

.course-card h4 {
  font-size: 0.97rem;
  color: var(--navy);
  margin-bottom: 8px;
  line-height: 1.3;
}

.course-card p {
  font-size: 0.85rem;
  color: var(--muted);
  line-height: 1.5;
}

/* =====================
   Course Pages
   ===================== */
.course-hero {
  background: linear-gradient(160deg, var(--navy) 0%, var(--dark) 60%, #1e3a6e 100%);
  padding: 120px 0 64px;
  color: var(--white);
}

.breadcrumb {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.78rem;
  color: rgba(255,255,255,0.5);
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.breadcrumb a { color: rgba(255,255,255,0.6); transition: var(--trans); }
.breadcrumb a:hover { color: var(--white); }
.breadcrumb span { color: rgba(255,255,255,0.35); }

.course-level-badge {
  display: inline-block;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.75rem;
  font-weight: 600;
  padding: 4px 12px;
  border-radius: 20px;
  margin-bottom: 14px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.course-hero h1 {
  color: var(--white);
  font-size: clamp(1.8rem, 4vw, 3rem);
  margin-bottom: 10px;
  line-height: 1.15;
}

.course-prefix {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.6em;
  color: #93c5fd;
  vertical-align: middle;
  margin-right: 4px;
}

.course-title-full {
  font-size: 1.15rem;
  color: rgba(255,255,255,0.7);
  font-family: 'Open Sans', sans-serif;
}

.course-body { padding: 72px 0; background: var(--white); }

.course-layout {
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 48px;
  align-items: start;
}

.course-main h2 {
  text-align: left;
  font-size: 1.25rem;
  margin-bottom: 12px;
  margin-top: 32px;
  color: var(--navy);
}
.course-main h2:first-child { margin-top: 0; }

.course-main > p {
  color: var(--muted);
  font-size: 1.02rem;
  margin-bottom: 16px;
}

.course-bullets {
  list-style: none;
  padding: 0;
  margin-bottom: 16px;
}
.course-bullets li {
  padding: 8px 0 8px 20px;
  position: relative;
  color: var(--muted);
  font-size: 0.97rem;
  border-bottom: 1px solid var(--border);
}
.course-bullets li:last-child { border-bottom: none; }
.course-bullets li::before {
  content: '›';
  position: absolute;
  left: 0;
  color: var(--blue);
  font-weight: 700;
}

.course-coming-soon {
  display: flex;
  gap: 16px;
  align-items: flex-start;
  background: #fffbeb;
  border: 1px solid #fcd34d;
  border-radius: var(--radius);
  padding: 20px 24px;
  margin-top: 32px;
}
.coming-soon-icon { font-size: 1.5rem; flex-shrink: 0; }
.course-coming-soon strong { display: block; color: var(--navy); margin-bottom: 4px; }
.course-coming-soon p { color: var(--muted); font-size: 0.9rem; margin: 0; }

.sidebar-card {
  background: var(--light);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px 22px;
  margin-bottom: 16px;
}
.sidebar-card h3 {
  font-size: 0.95rem;
  margin-bottom: 16px;
  color: var(--navy);
  text-align: left;
}

.course-dl { display: grid; grid-template-columns: auto 1fr; gap: 8px 16px; }
.course-dl dt {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.75rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding-top: 2px;
}
.course-dl dd { font-size: 0.9rem; color: var(--text); }
.course-dl code {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.82rem;
  color: var(--blue);
  background: #eff6ff;
  padding: 2px 6px;
  border-radius: 3px;
}

.btn-back {
  display: block;
  text-align: center;
  background: var(--light);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 10px;
  font-family: 'Montserrat', sans-serif;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--navy);
  transition: var(--trans);
}
.btn-back:hover { background: var(--blue); color: var(--white); border-color: var(--blue); }

@media (max-width: 940px) {
  .nav-toggle { display: block; }
  .nav-links {
    display: none;
    flex-direction: column;
    position: absolute;
    top: 68px; left: 0; right: 0;
    background: var(--white);
    padding: 20px 24px;
    gap: 18px;
    box-shadow: 0 8px 20px rgba(0,0,0,0.1);
    border-top: 1px solid var(--border);
  }
  .nav-links.open { display: flex; }
}

@media (max-width: 768px) {
  .course-layout { grid-template-columns: 1fr; }
  .course-sidebar { order: -1; }
  .courses-grid { grid-template-columns: 1fr; }
  .focus-grid { grid-template-columns: 1fr; }
}

/* =====================
   Footer
   ===================== */
.footer {
  background: var(--navy);
  color: rgba(255,255,255,0.6);
  padding: 44px 0;
  text-align: center;
}

.footer-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

.footer-name {
  font-family: 'Montserrat', sans-serif;
  font-weight: 700;
  font-size: 1rem;
  color: var(--white);
}

.footer p { font-size: 0.88rem; }
.footer-tagline {
  color: rgba(255,255,255,0.35);
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.78rem;
}

/* =====================
   Responsive
   ===================== */
@media (max-width: 768px) {
  .about-inner { grid-template-columns: 1fr; }
  .about-stats-card { grid-template-columns: 1fr 1fr; }

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

  .timeline { padding-left: 24px; }
  .timeline-dot { left: -20px; }
}