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

:root {
  --primary:   #1a56db;
  --primary-dark: #1341b0;
  --accent:    #f59e0b;
  --bg:        #f8fafc;
  --bg-alt:    #eef2f7;
  --card:      #ffffff;
  --text:      #1e293b;
  --text-muted:#64748b;
  --border:    #e2e8f0;
  --radius:    12px;
  --shadow:    0 4px 24px rgba(0,0,0,.08);
  --transition:0.25s ease;
}

html { scroll-behavior: smooth; }
body {
  font-family: 'Inter', system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  font-size: 16px;
}

/* ===========================
   TYPOGRAPHY
   =========================== */
h1,h2,h3 { font-family: 'Playfair Display', serif; }
a { color: var(--primary); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--primary-dark); }
ul { list-style: none; }

/* ===========================
   NAVBAR
   =========================== */
#navbar {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  background: rgba(255,255,255,0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  box-shadow: 0 2px 12px rgba(0,0,0,.06);
}
.nav-inner {
  max-width: 1200px; margin: 0 auto;
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 1.5rem; height: 64px;
}
.nav-logo {
  font-family: 'Playfair Display', serif;
  font-size: 1.15rem; font-weight: 700;
  color: var(--primary);
  white-space: nowrap;
}
.nav-links {
  display: flex; gap: 0.25rem; align-items: center; flex-wrap: wrap;
}
.nav-links a {
  color: var(--text); font-size: .88rem; font-weight: 500;
  padding: .4rem .65rem; border-radius: 6px;
  transition: background var(--transition), color var(--transition);
}
.nav-links a:hover { background: var(--bg-alt); color: var(--primary); }
.hamburger { display: none; background: none; border: none; cursor: pointer; font-size: 1.4rem; color: var(--text); }

/* ===========================
   HERO
   =========================== */
#hero {
  min-height: 100vh;
  display: flex; align-items: center; justify-content: center;
  text-align: center; position: relative; overflow: hidden;
  background: linear-gradient(135deg, #0f2b6b 0%, #1a56db 50%, #0e4aad 100%);
  padding: 7rem 1.5rem 4rem;
}
.hero-bg {
  position: absolute; inset: 0; opacity: .08;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='1'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E") repeat;
}
.hero-content { position: relative; z-index: 1; max-width: 800px; }
.hero-avatar {
  width: 110px; height: 110px; border-radius: 50%;
  background: rgba(255,255,255,.15);
  border: 3px solid rgba(255,255,255,.4);
  display: flex; align-items: center; justify-content: center;
  margin: 0 auto 1.5rem; overflow: hidden;
}
.hero-avatar img {
  width: 100%; height: 100%; object-fit: cover; object-position: center 20%;
}
#hero h1 { font-size: clamp(2.2rem,5vw,3.5rem); color: #fff; margin-bottom: .5rem; }
.hero-title { color: rgba(255,255,255,.8); font-size: 1.1rem; margin-bottom: .75rem; }
.hero-tagline { color: var(--accent); font-weight: 600; margin-bottom: 1.5rem; font-size: 1rem; }
.hero-badges { display: flex; flex-wrap: wrap; gap: .6rem; justify-content: center; margin-bottom: 2rem; }
.badge {
  background: rgba(255,255,255,.15); color: #fff;
  border: 1px solid rgba(255,255,255,.3);
  padding: .35rem .9rem; border-radius: 999px; font-size: .82rem;
  display: flex; align-items: center; gap: .4rem;
}
.hero-cta { display: flex; gap: 1rem; justify-content: center; flex-wrap: wrap; }
.btn {
  padding: .75rem 1.8rem; border-radius: 8px; font-weight: 600;
  font-size: .95rem; transition: all var(--transition); cursor: pointer;
}
.btn-primary { background: var(--accent); color: #1e293b; }
.btn-primary:hover { background: #d97706; color: #1e293b; transform: translateY(-2px); }
.btn-outline {
  background: transparent; color: #fff;
  border: 2px solid rgba(255,255,255,.5);
}
.btn-outline:hover { background: rgba(255,255,255,.1); border-color: #fff; color: #fff; transform: translateY(-2px); }

/* ===========================
   SECTIONS
   =========================== */
.section { padding: 5rem 1.5rem; }
.section-alt { background: var(--bg-alt); }
.container { max-width: 1100px; margin: 0 auto; }
.section-title {
  font-size: clamp(1.8rem,3vw,2.4rem);
  color: var(--primary); margin-bottom: 2.5rem; text-align: center;
  position: relative;
}
.section-title::after {
  content: ''; display: block; width: 60px; height: 4px;
  background: var(--accent); margin: .75rem auto 0; border-radius: 4px;
}
.subsection-title {
  font-size: 1.35rem; color: var(--text); margin: 2.5rem 0 1.25rem;
  display: flex; align-items: center; gap: .6rem;
}

/* ===========================
   ABOUT
   =========================== */
.about-grid {
  display: grid; grid-template-columns: 1fr 1fr;
  gap: 3rem; align-items: center;
}
.about-text p { color: var(--text-muted); margin-bottom: 1rem; font-size: 1.05rem; }
.about-text strong { color: var(--text); }
.about-stats {
  display: grid; grid-template-columns: 1fr 1fr; gap: 1rem;
}
.stat-card {
  background: var(--card); border-radius: var(--radius);
  box-shadow: var(--shadow); padding: 1.5rem; text-align: center;
  border-top: 4px solid var(--primary);
}
.stat-num { display: block; font-size: 2.2rem; font-weight: 700; color: var(--primary); }
.stat-label { font-size: .85rem; color: var(--text-muted); margin-top: .25rem; }

/* ===========================
   TIMELINE (EXPERIENCE)
   =========================== */
.timeline { position: relative; padding-left: 2.5rem; }
.timeline::before {
  content: ''; position: absolute; left: 12px; top: 0; bottom: 0;
  width: 3px; background: var(--border); border-radius: 2px;
}
.timeline-item { position: relative; margin-bottom: 2rem; }
.timeline-dot {
  position: absolute; left: -2.05rem; top: 1.25rem;
  width: 14px; height: 14px; border-radius: 50%;
  background: var(--primary); border: 3px solid var(--bg-alt);
  box-shadow: 0 0 0 2px var(--primary);
}
.timeline-card {
  background: var(--card); border-radius: var(--radius);
  box-shadow: var(--shadow); padding: 1.75rem;
  border-left: 4px solid var(--primary);
  transition: transform var(--transition), box-shadow var(--transition);
}
.timeline-card:hover { transform: translateY(-3px); box-shadow: 0 8px 32px rgba(0,0,0,.12); }
.timeline-header {
  display: flex; align-items: center; gap: .75rem;
  margin-bottom: .5rem; flex-wrap: wrap;
}
.timeline-period { color: var(--primary); font-weight: 600; font-size: .9rem; }
.timeline-type {
  background: var(--bg-alt); color: var(--text-muted);
  font-size: .75rem; padding: .2rem .65rem; border-radius: 999px;
}
.timeline-role { font-size: 1.2rem; color: var(--text); margin-bottom: .35rem; }
.timeline-org { color: var(--text-muted); font-size: .9rem; margin-bottom: .75rem; display: flex; align-items: center; gap: .4rem; }
.timeline-card ul { padding-left: 1.25rem; list-style: disc; }
.timeline-card ul li { color: var(--text-muted); margin-bottom: .4rem; font-size: .95rem; }

/* ===========================
   EDUCATION
   =========================== */
.edu-grid { display: grid; grid-template-columns: repeat(auto-fit,minmax(280px,1fr)); gap: 1.5rem; }
.edu-card {
  background: var(--card); border-radius: var(--radius);
  box-shadow: var(--shadow); padding: 1.75rem;
  display: flex; gap: 1rem; align-items: flex-start;
  transition: transform var(--transition);
}
.edu-card:hover { transform: translateY(-3px); }
.edu-icon {
  flex-shrink: 0; width: 48px; height: 48px;
  background: var(--primary); color: #fff;
  border-radius: 10px; display: flex; align-items: center; justify-content: center;
  font-size: 1.2rem;
}
.edu-degree { display: block; font-weight: 700; font-size: 1.05rem; color: var(--text); margin-bottom: .25rem; }
.edu-year { display: block; color: var(--primary); font-size: .85rem; font-weight: 600; margin-bottom: .5rem; }
.edu-uni { color: var(--text-muted); font-size: .9rem; margin-bottom: .4rem; display: flex; align-items: center; gap: .4rem; }
.edu-grade { color: var(--accent); font-size: .88rem; font-weight: 600; margin-bottom: .6rem; display: flex; align-items: center; gap: .4rem; }
.edu-modules { color: var(--text-muted); font-size: .84rem; line-height: 1.6; }

/* ===========================
   SKILLS
   =========================== */
.skills-grid { display: grid; grid-template-columns: repeat(auto-fit,minmax(250px,1fr)); gap: 1.5rem; }
.skill-group {
  background: var(--card); border-radius: var(--radius);
  box-shadow: var(--shadow); padding: 1.5rem;
}
.skill-group h3 { font-size: 1rem; color: var(--text); margin-bottom: 1rem; font-family: 'Inter',sans-serif; font-weight: 600; display: flex; align-items: center; gap: .5rem; }
.skill-tags { display: flex; flex-wrap: wrap; gap: .5rem; }
.tag {
  font-size: .8rem; padding: .3rem .75rem; border-radius: 999px; font-weight: 500;
}
.tag-advanced { background: #dbeafe; color: #1e40af; }
.tag-medium   { background: #fef3c7; color: #92400e; }
.tag-basic    { background: #f1f5f9; color: #64748b; }
.skill-legend { display: flex; gap: .75rem; margin-top: 1.5rem; justify-content: center; }
.website-tags { display: flex; flex-wrap: wrap; gap: .6rem; margin-top: .75rem; }
.wtag {
  background: var(--primary); color: #fff;
  padding: .35rem .9rem; border-radius: 6px; font-size: .82rem; font-weight: 500;
}

/* ===========================
   PROJECTS
   =========================== */
.projects-grid { display: grid; grid-template-columns: repeat(auto-fit,minmax(280px,1fr)); gap: 1.5rem; }
.project-card {
  background: var(--card); border-radius: var(--radius);
  box-shadow: var(--shadow); padding: 1.75rem;
  border-top: 4px solid var(--accent);
  transition: transform var(--transition);
}
.project-card:hover { transform: translateY(-4px); }
.project-period { color: var(--accent); font-weight: 700; font-size: .85rem; margin-bottom: .4rem; }
.project-card h3 { font-size: 1.25rem; color: var(--text); margin-bottom: .35rem; }
.project-role {
  display: inline-block; background: var(--bg-alt); color: var(--primary);
  font-size: .8rem; font-weight: 600; padding: .2rem .65rem;
  border-radius: 999px; margin-bottom: .75rem;
}
.project-card p { color: var(--text-muted); font-size: .92rem; margin-bottom: 1rem; }
.project-tags { display: flex; flex-wrap: wrap; gap: .4rem; }
.project-tags span {
  background: var(--bg-alt); color: var(--text-muted);
  font-size: .75rem; padding: .2rem .55rem; border-radius: 999px;
}

/* ===========================
   ACHIEVEMENTS
   =========================== */
.achieve-grid { display: grid; grid-template-columns: repeat(auto-fit,minmax(300px,1fr)); gap: 1.5rem; }
.achieve-block {
  background: var(--card); border-radius: var(--radius);
  box-shadow: var(--shadow); padding: 1.75rem;
}
.achieve-block h3 {
  font-size: 1.1rem; font-family: 'Inter',sans-serif; font-weight: 700;
  color: var(--primary); margin-bottom: 1.25rem;
  display: flex; align-items: center; gap: .5rem;
}
.achieve-list li { display: flex; gap: .6rem; align-items: flex-start; margin-bottom: .75rem; color: var(--text-muted); font-size: .93rem; }
.achieve-list li i { color: var(--accent); flex-shrink: 0; margin-top: .25rem; }

.hindex-grid { display: grid; grid-template-columns: repeat(2,1fr); gap: .75rem; }
.hindex-card {
  background: var(--bg-alt); border-radius: 8px; padding: 1rem;
  text-align: center; border-top: 3px solid var(--primary);
}
.hindex-num { display: block; font-size: 2rem; font-weight: 700; color: var(--primary); }
.hindex-src { font-size: .78rem; color: var(--text-muted); }

.funding-list { }
.funding-list li { display: flex; gap: .75rem; align-items: baseline; margin-bottom: .7rem; color: var(--text-muted); font-size: .9rem; }
.funding-year {
  flex-shrink: 0; background: var(--primary); color: #fff;
  padding: .15rem .55rem; border-radius: 4px; font-size: .78rem; font-weight: 700;
}

/* ===========================
   PUBLICATIONS
   =========================== */
.pub-note { color: var(--text-muted); font-size: .9rem; margin-bottom: 2rem; text-align: center; }
.pub-year-group { margin-bottom: 2rem; }
.pub-year {
  font-size: 1.25rem; color: var(--primary); margin-bottom: .75rem;
  padding-bottom: .4rem; border-bottom: 2px solid var(--border);
  font-family: 'Inter',sans-serif; font-weight: 700;
}
.pub-list { padding-left: 1.5rem; list-style: decimal; }
.pub-list li { color: var(--text-muted); font-size: .9rem; margin-bottom: .6rem; line-height: 1.6; }
.pub-list em { font-style: italic; }
.if { background: #dbeafe; color: #1e40af; font-size: .75rem; padding: .15rem .5rem; border-radius: 4px; font-weight: 600; white-space: nowrap; }

.book-list { padding-left: 1.5rem; list-style: disc; }
.book-list li { color: var(--text-muted); font-size: .9rem; margin-bottom: .6rem; }

/* ===========================
   TALKS
   =========================== */
.talks-grid { display: grid; grid-template-columns: repeat(auto-fit,minmax(280px,1fr)); gap: 1.5rem; }
.talks-block {
  background: var(--card); border-radius: var(--radius);
  box-shadow: var(--shadow); padding: 1.75rem;
}
.talks-block h3 {
  font-size: 1.05rem; font-family: 'Inter',sans-serif; font-weight: 700;
  color: var(--primary); margin-bottom: 1rem;
  display: flex; align-items: center; gap: .5rem;
}
.talks-list { }
.talks-list li { display: flex; gap: .75rem; align-items: baseline; color: var(--text-muted); font-size: .9rem; margin-bottom: .6rem; }
.talk-year {
  flex-shrink: 0; background: var(--accent); color: #fff;
  padding: .1rem .5rem; border-radius: 4px; font-size: .78rem; font-weight: 700;
}
.reviewer-text { color: var(--text-muted); font-size: .88rem; line-height: 1.7; }
.lang-tags { display: flex; flex-wrap: wrap; gap: .75rem; margin-top: .5rem; }
.lang-tag {
  background: var(--bg-alt); color: var(--text);
  padding: .5rem 1.1rem; border-radius: 8px; font-weight: 600;
  display: flex; align-items: center; gap: .5rem; font-size: .9rem;
}
.lang-tag i { color: var(--primary); font-size: .55rem; }

/* ===========================
   CONTACT
   =========================== */
#contact { background: linear-gradient(135deg,#0f2b6b,#1a56db); }
#contact .section-title { color: #fff; }
#contact .section-title::after { background: var(--accent); }
.contact-grid { display: grid; grid-template-columns: repeat(auto-fit,minmax(220px,1fr)); gap: 1rem; }
.contact-card {
  background: rgba(255,255,255,.1); border: 1px solid rgba(255,255,255,.2);
  color: #fff; border-radius: var(--radius); padding: 1.5rem;
  display: flex; flex-direction: column; align-items: center; gap: .6rem;
  text-align: center; transition: background var(--transition), transform var(--transition);
}
.contact-card:hover { background: rgba(255,255,255,.2); transform: translateY(-3px); color: #fff; }
.contact-card i { font-size: 1.6rem; }
.contact-card span { font-size: .88rem; word-break: break-all; }

/* ===========================
   FOOTER
   =========================== */
footer {
  background: #0f172a; color: rgba(255,255,255,.5);
  text-align: center; padding: 1.5rem; font-size: .85rem;
}

/* ===========================
   BACK TO TOP
   =========================== */
.back-to-top {
  position: fixed; bottom: 1.5rem; right: 1.5rem;
  width: 44px; height: 44px; background: var(--primary); color: #fff;
  border-radius: 50%; display: flex; align-items: center; justify-content: center;
  box-shadow: 0 4px 16px rgba(26,86,219,.4);
  opacity: 0; pointer-events: none;
  transition: opacity var(--transition), transform var(--transition);
  z-index: 900;
}
.back-to-top.visible { opacity: 1; pointer-events: all; }
.back-to-top:hover { transform: translateY(-3px); color: #fff; }

/* ===========================
   RESPONSIVE
   =========================== */
@media (max-width: 768px) {
  .hamburger { display: block; }
  .nav-links {
    display: none; position: absolute; top: 64px; left: 0; right: 0;
    background: #fff; flex-direction: column; padding: 1rem 1.5rem 1.5rem;
    border-bottom: 1px solid var(--border); box-shadow: 0 4px 16px rgba(0,0,0,.08);
    gap: 0;
  }
  .nav-links.open { display: flex; }
  .nav-links a { padding: .6rem .5rem; font-size: .95rem; }
  .about-grid { grid-template-columns: 1fr; }
  .timeline { padding-left: 1.75rem; }
  .timeline-dot { left: -1.55rem; }
}
@media (max-width: 480px) {
  .about-stats { grid-template-columns: 1fr 1fr; }
  .hindex-grid { grid-template-columns: 1fr 1fr; }
}