/* ============================================================
   Daniel Chuks Ugbajah — Portfolio Website Styles
   ============================================================ */

/* ---- ROOT VARIABLES ---- */
:root {
  --deep-green: #0B5D3B;
  --emerald: #14A86B;
  --emerald-light: #1ec87d;
  --navy: #0B1F33;
  --navy-mid: #12284a;
  --light-gray: #F5F7FA;
  --white: #FFFFFF;
  --gold: #F4B942;
  --gold-dark: #d9a031;
  --text-dark: #1a2332;
  --text-mid: #3d4f63;
  --text-light: #6b7b8d;
  --border: #e4e8ed;
  --shadow-sm: 0 2px 8px rgba(11,31,51,0.08);
  --shadow-md: 0 8px 24px rgba(11,31,51,0.12);
  --shadow-lg: 0 20px 50px rgba(11,31,51,0.16);
  --radius: 12px;
  --radius-sm: 8px;
  --radius-lg: 20px;
  --transition: 0.3s ease;
}

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

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

body {
  font-family: 'Inter', sans-serif;
  color: var(--text-dark);
  background: var(--white);
  line-height: 1.65;
  overflow-x: hidden;
}

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

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ---- SECTION SHARED ---- */
.section { padding: 100px 0; }
.bg-light { background: var(--light-gray); }
.bg-dark { background: var(--navy); }

.section-header {
  text-align: center;
  margin-bottom: 60px;
}

.section-tag {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--emerald);
  background: rgba(20, 168, 107, 0.1);
  padding: 4px 16px;
  border-radius: 20px;
  margin-bottom: 14px;
}

.section-tag-light {
  color: var(--gold);
  background: rgba(244, 185, 66, 0.15);
}

.section-title {
  font-family: 'Poppins', sans-serif;
  font-size: 2.4rem;
  font-weight: 700;
  color: var(--navy);
  line-height: 1.2;
}

.section-title-light { color: var(--white); }

.section-subtitle {
  margin-top: 14px;
  color: var(--text-light);
  font-size: 1rem;
  max-width: 620px;
  margin-left: auto;
  margin-right: auto;
}

.section-subtitle-light { color: rgba(255,255,255,0.7); }

/* ============================================================
   BUTTONS
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 26px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  transition: all var(--transition);
  white-space: nowrap;
  border: 2px solid transparent;
}

.btn-primary {
  background: var(--emerald);
  color: var(--white);
  border-color: var(--emerald);
}
.btn-primary:hover { background: var(--deep-green); border-color: var(--deep-green); transform: translateY(-2px); }

.btn-gold {
  background: var(--gold);
  color: var(--navy);
  border-color: var(--gold);
}
.btn-gold:hover { background: var(--gold-dark); border-color: var(--gold-dark); transform: translateY(-2px); }

.btn-outline-light {
  background: transparent;
  color: var(--white);
  border-color: rgba(255,255,255,0.5);
}
.btn-outline-light:hover { border-color: var(--white); background: rgba(255,255,255,0.1); }

.btn-full-width { width: 100%; justify-content: center; }

/* ============================================================
   NAVBAR
   ============================================================ */
.navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  padding: 18px 0;
  transition: all var(--transition);
}

.navbar.scrolled {
  background: rgba(11,31,51,0.97);
  backdrop-filter: blur(12px);
  padding: 12px 0;
  box-shadow: 0 2px 20px rgba(0,0,0,0.2);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--white);
  font-weight: 600;
}

.logo-initials {
  width: 38px; height: 38px;
  background: var(--emerald);
  border-radius: 8px;
  display: grid;
  place-items: center;
  font-family: 'Poppins', sans-serif;
  font-size: 0.85rem;
  font-weight: 700;
  color: white;
}

.logo-name { font-size: 0.95rem; color: rgba(255,255,255,0.9); }

.nav-links {
  display: flex;
  align-items: center;
  gap: 6px;
}

.nav-link {
  padding: 8px 14px;
  font-size: 0.88rem;
  font-weight: 500;
  color: rgba(255,255,255,0.8);
  border-radius: 6px;
  transition: all var(--transition);
}

.nav-link:hover, .nav-link.active {
  color: var(--emerald);
  background: rgba(20,168,107,0.1);
}

.nav-cta {
  background: var(--emerald);
  color: var(--white) !important;
  padding: 8px 18px;
}
.nav-cta:hover { background: var(--deep-green) !important; }

.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
}
.hamburger span {
  display: block;
  width: 22px; height: 2px;
  background: white;
  border-radius: 2px;
  transition: all var(--transition);
}

/* ============================================================
   HERO
   ============================================================ */
.hero {
  min-height: 100vh;
  background: linear-gradient(135deg, var(--navy) 0%, var(--navy-mid) 50%, #0d3d2a 100%);
  display: flex;
  align-items: center;
  position: relative;
  overflow: hidden;
  padding-top: 80px;
}

.hero-bg-shapes { position: absolute; inset: 0; pointer-events: none; overflow: hidden; }
.shape {
  position: absolute;
  border-radius: 50%;
  opacity: 0.06;
  background: var(--emerald);
}
.shape-1 { width: 600px; height: 600px; top: -200px; right: -100px; }
.shape-2 { width: 350px; height: 350px; bottom: -100px; left: 10%; background: var(--gold); opacity: 0.04; }
.shape-3 { width: 200px; height: 200px; top: 40%; left: 5%; }

.hero-inner {
  position: relative;
  z-index: 2;
  max-width: 1200px;
  margin: 0 auto;
  padding: 60px 24px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
  width: 100%;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(20,168,107,0.15);
  border: 1px solid rgba(20,168,107,0.3);
  color: var(--emerald-light);
  padding: 6px 16px;
  border-radius: 20px;
  font-size: 0.82rem;
  font-weight: 500;
  margin-bottom: 24px;
}

.badge-dot {
  width: 8px; height: 8px;
  background: var(--emerald-light);
  border-radius: 50%;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(0.8); }
}

.hero-name {
  font-family: 'Poppins', sans-serif;
  font-size: 3.4rem;
  font-weight: 800;
  color: var(--white);
  line-height: 1.1;
  margin-bottom: 16px;
}

.name-highlight {
  color: var(--emerald);
  display: block;
}

.hero-title {
  font-size: 1.05rem;
  color: rgba(255,255,255,0.7);
  margin-bottom: 16px;
  line-height: 1.5;
}

.hero-tagline {
  font-size: 1.1rem;
  color: var(--gold);
  font-weight: 500;
  margin-bottom: 36px;
  line-height: 1.5;
}

.hero-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* Hero photo */
.hero-avatar-side {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 28px;
}

.hero-photo-ring {
  width: 240px; height: 240px;
  background: linear-gradient(135deg, var(--emerald), var(--gold));
  border-radius: 50%;
  display: grid;
  place-items: center;
  padding: 4px;
}

.hero-photo-frame {
  width: 100%; height: 100%;
  border-radius: 50%;
  overflow: hidden;
  background: var(--navy-mid);
  display: flex;
  align-items: center;
  justify-content: center;
}

.hero-photo {
  width: 100%; height: 100%;
  object-fit: cover;
  border-radius: 50%;
}

.hero-initials-fallback {
  display: none;
  width: 100%; height: 100%;
  align-items: center;
  justify-content: center;
  font-family: 'Poppins', sans-serif;
  font-size: 4rem;
  font-weight: 800;
  color: var(--emerald);
  border-radius: 50%;
  background: var(--navy-mid);
}

.hero-stats-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  width: 100%;
}

.stat-card {
  background: rgba(255,255,255,0.07);
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: var(--radius-sm);
  padding: 16px;
  text-align: center;
  backdrop-filter: blur(8px);
  transition: all var(--transition);
}
.stat-card:hover { background: rgba(20,168,107,0.1); border-color: rgba(20,168,107,0.3); }

.stat-num {
  display: block;
  font-family: 'Poppins', sans-serif;
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--emerald-light);
}

.stat-lbl {
  display: block;
  font-size: 0.72rem;
  color: rgba(255,255,255,0.6);
  margin-top: 4px;
  line-height: 1.3;
}

.hero-scroll {
  position: absolute;
  bottom: 36px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 2;
}

.scroll-dot {
  width: 14px; height: 14px;
  border: 2px solid rgba(255,255,255,0.4);
  border-radius: 50%;
  animation: bounce 2s ease infinite;
}

@keyframes bounce {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(8px); }
}

/* ============================================================
   ABOUT
   ============================================================ */
.about-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  gap: 60px;
  align-items: start;
}

.about-lead {
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--navy);
  margin-bottom: 16px;
  line-height: 1.5;
}

.about-text-col p { color: var(--text-mid); margin-bottom: 14px; }

.about-pillars {
  margin-top: 32px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.pillar {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  padding: 16px;
  background: var(--light-gray);
  border-radius: var(--radius-sm);
  border-left: 3px solid var(--emerald);
}

.pillar-icon {
  font-size: 1.4rem;
  width: 36px;
  flex-shrink: 0;
  margin-top: 2px;
}

.pillar-text {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.pillar-text strong { font-size: 0.95rem; color: var(--navy); }
.pillar-text span { font-size: 0.85rem; color: var(--text-mid); }

.contact-card {
  background: var(--navy);
  color: white;
  border-radius: var(--radius-lg);
  padding: 32px;
}

.contact-card h3 {
  font-family: 'Poppins', sans-serif;
  font-size: 1.2rem;
  margin-bottom: 24px;
  color: var(--white);
}

.contact-item {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  margin-bottom: 16px;
}

.c-icon { font-size: 1rem; margin-top: 2px; }

.contact-item a, .contact-item span {
  font-size: 0.88rem;
  color: rgba(255,255,255,0.75);
  word-break: break-word;
  transition: color var(--transition);
}
.contact-item a:hover { color: var(--emerald-light); }

.quick-stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-top: 24px;
  padding-top: 24px;
  border-top: 1px solid rgba(255,255,255,0.1);
}

.q-stat { text-align: center; }

.q-num {
  display: block;
  font-family: 'Poppins', sans-serif;
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--gold);
}

.q-lbl {
  display: block;
  font-size: 0.75rem;
  color: rgba(255,255,255,0.55);
  margin-top: 4px;
}

/* ============================================================
   EDUCATION
   ============================================================ */
.timeline {
  position: relative;
  padding-left: 40px;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 12px;
  top: 0; bottom: 0;
  width: 2px;
  background: linear-gradient(to bottom, var(--emerald), var(--gold), var(--deep-green));
}

.timeline-item {
  position: relative;
  margin-bottom: 40px;
}

.timeline-dot {
  position: absolute;
  left: -34px;
  top: 24px;
  width: 18px; height: 18px;
  background: var(--emerald);
  border: 3px solid var(--white);
  border-radius: 50%;
  box-shadow: 0 0 0 3px var(--emerald);
}

.timeline-dot-gold { background: var(--gold); box-shadow: 0 0 0 3px var(--gold); }
.degree-dot-navy { background: var(--navy); box-shadow: 0 0 0 3px var(--navy); }

.timeline-card {
  background: var(--white);
  border-radius: var(--radius);
  padding: 28px 32px;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border);
  transition: all var(--transition);
}
.timeline-card:hover { box-shadow: var(--shadow-md); transform: translateY(-2px); }

.timeline-card-accent {
  border-left: 3px solid var(--gold);
}

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

.degree-badge {
  display: inline-block;
  padding: 3px 10px;
  background: rgba(20,168,107,0.1);
  color: var(--emerald);
  border-radius: 20px;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.5px;
  margin-bottom: 6px;
}

.degree-badge-gold { background: rgba(244,185,66,0.12); color: var(--gold-dark); }
.degree-badge-navy { background: rgba(11,31,51,0.08); color: var(--navy); }

.timeline-card h3 {
  font-family: 'Poppins', sans-serif;
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--navy);
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.major-tag {
  font-size: 0.72rem;
  font-weight: 500;
  background: rgba(11,93,59,0.08);
  color: var(--deep-green);
  padding: 2px 10px;
  border-radius: 12px;
}

.tl-institution {
  font-size: 0.85rem;
  color: var(--text-light);
  margin-top: 4px;
}

.tl-meta { text-align: right; flex-shrink: 0; }

.tl-date {
  display: block;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--text-light);
  white-space: nowrap;
}

.tl-gpa {
  display: block;
  font-size: 0.78rem;
  color: var(--emerald);
  margin-top: 4px;
  font-weight: 500;
}

.tl-desc {
  font-size: 0.9rem;
  color: var(--text-mid);
  line-height: 1.6;
  margin-top: 10px;
}

.tl-transcript-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: 16px;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--deep-green);
  background: rgba(11,93,59,0.07);
  border: 1px solid rgba(11,93,59,0.2);
  padding: 7px 16px;
  border-radius: 6px;
  transition: all var(--transition);
}

.tl-transcript-btn:hover {
  background: var(--deep-green);
  color: var(--white);
  border-color: var(--deep-green);
  transform: translateY(-1px);
}

/* ============================================================
   PROJECTS — PDF-BASED CARDS
   ============================================================ */
.projects-section { background: var(--white); }

.proj-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  margin-bottom: 48px;
  box-shadow: var(--shadow-md);
  transition: all 0.4s ease;
}

.proj-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-4px);
}

.proj-top {
  padding: 28px 32px 20px;
}

.proj-label {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 12px;
}

.proj-num {
  font-family: 'Poppins', sans-serif;
  font-size: 2rem;
  font-weight: 800;
  color: var(--border);
  line-height: 1;
}

.proj-cat {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  color: var(--emerald);
  background: rgba(20,168,107,0.08);
  padding: 3px 12px;
  border-radius: 20px;
}

.proj-title {
  font-family: 'Poppins', sans-serif;
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--navy);
  margin-bottom: 16px;
  line-height: 1.3;
}

.tech-stack {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tech-badge {
  font-size: 0.78rem;
  font-weight: 600;
  padding: 4px 12px;
  border-radius: 20px;
  background: var(--navy);
  color: var(--white);
}

/* PDF Preview Area */
.proj-pdf-area {
  position: relative;
  width: 100%;
  height: 520px;
  background: #1a2640;
  overflow: hidden;
}

.proj-pdf-frame {
  width: 100%;
  height: 100%;
  border: none;
  display: block;
}

.proj-pdf-overlay {
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  background: rgba(11,31,51,0);
  display: flex;
  align-items: flex-end;
  justify-content: flex-end;
  padding: 20px;
  transition: background 0.3s ease;
  pointer-events: none;
}

.proj-card:hover .proj-pdf-overlay {
  background: rgba(11,31,51,0.45);
  pointer-events: all;
}

.pdf-open-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--emerald);
  color: white;
  padding: 12px 24px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.9rem;
  opacity: 0;
  transform: translateY(12px);
  transition: all 0.3s ease;
  pointer-events: all;
}

.proj-card:hover .pdf-open-btn {
  opacity: 1;
  transform: translateY(0);
}

.pdf-open-btn:hover {
  background: var(--deep-green);
  transform: scale(1.03) !important;
}

/* Project body text area */
.proj-body {
  padding: 24px 32px 32px;
  border-top: 1px solid var(--border);
}

.proj-body p {
  color: var(--text-mid);
  line-height: 1.7;
  margin-bottom: 20px;
  font-size: 0.95rem;
}

.proj-highlights {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.ph-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  font-size: 0.85rem;
  color: var(--text-mid);
  line-height: 1.5;
}

.ph-dot {
  width: 6px; height: 6px;
  background: var(--emerald);
  border-radius: 50%;
  margin-top: 7px;
  flex-shrink: 0;
}

/* ============================================================
   RESEARCH SECTION
   ============================================================ */
.research-focus-block {
  display: flex;
  align-items: flex-start;
  gap: 24px;
  background: linear-gradient(135deg, rgba(11,93,59,0.06) 0%, rgba(20,168,107,0.04) 100%);
  border: 1px solid rgba(20,168,107,0.2);
  border-left: 4px solid var(--emerald);
  border-radius: var(--radius);
  padding: 32px 36px;
  margin-bottom: 56px;
}

.rfb-icon {
  font-size: 2.5rem;
  flex-shrink: 0;
  margin-top: 4px;
}

.rfb-text h3 {
  font-family: 'Poppins', sans-serif;
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--deep-green);
  margin-bottom: 12px;
}

.rfb-text p {
  color: var(--text-mid);
  line-height: 1.75;
  font-size: 1.02rem;
}

/* Research Directions */
.research-directions { margin-bottom: 60px; }

.rdir-title {
  font-family: 'Poppins', sans-serif;
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--navy);
  margin-bottom: 24px;
}

.rdir-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 14px;
}

.rdir-card {
  display: flex;
  align-items: center;
  gap: 12px;
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 14px 16px;
  font-size: 0.88rem;
  font-weight: 500;
  color: var(--text-dark);
  transition: all var(--transition);
  box-shadow: var(--shadow-sm);
}

.rdir-card:hover {
  border-color: var(--emerald);
  background: rgba(20,168,107,0.04);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.rdir-icon { font-size: 1.4rem; flex-shrink: 0; }

/* Publications */
.research-works { }

.pubs-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}

.pub-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
}

.pub-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: var(--emerald);
}

.pub-card-featured::before {
  background: linear-gradient(90deg, var(--gold), var(--emerald));
}

.pub-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-3px);
}

.pub-date-badge {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--emerald);
  background: rgba(20,168,107,0.08);
  padding: 3px 12px;
  border-radius: 20px;
  margin-bottom: 8px;
}

.pub-date-gold {
  color: var(--gold-dark);
  background: rgba(244,185,66,0.12);
}

.pub-type {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  color: var(--text-light);
  margin-bottom: 10px;
}

.pub-card h4 {
  font-family: 'Poppins', sans-serif;
  font-size: 0.98rem;
  font-weight: 600;
  color: var(--navy);
  line-height: 1.45;
  margin-bottom: 12px;
}

.pub-card p {
  font-size: 0.86rem;
  color: var(--text-mid);
  line-height: 1.65;
  margin-bottom: 16px;
}

.pub-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.pub-tags span {
  font-size: 0.72rem;
  font-weight: 600;
  padding: 3px 10px;
  border-radius: 20px;
  background: var(--light-gray);
  color: var(--text-mid);
}

/* ============================================================
   SKILLS
   ============================================================ */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.skill-group {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition);
}

.skill-group:hover {
  box-shadow: var(--shadow-md);
  border-color: rgba(20,168,107,0.3);
  transform: translateY(-2px);
}

.skill-group-icon {
  font-size: 1.8rem;
  margin-bottom: 12px;
}

.skill-group h3 {
  font-family: 'Poppins', sans-serif;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--navy);
  margin-bottom: 14px;
}

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

.skill-tags span {
  font-size: 0.76rem;
  font-weight: 500;
  padding: 4px 10px;
  border-radius: 20px;
  background: rgba(20,168,107,0.07);
  color: var(--deep-green);
  border: 1px solid rgba(20,168,107,0.15);
  transition: all var(--transition);
}

.skill-tags span:hover {
  background: var(--emerald);
  color: white;
  border-color: var(--emerald);
}

/* ============================================================
   CERTIFICATIONS
   ============================================================ */
.certs-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
}

.cert-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  box-shadow: var(--shadow-sm);
  cursor: pointer;
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
}

.cert-card:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--emerald);
  transform: translateY(-3px);
}

.cert-ribbon {
  position: absolute;
  top: 0; right: 0;
  width: 0; height: 0;
  border-style: solid;
  border-width: 0 32px 32px 0;
  border-color: transparent var(--emerald) transparent transparent;
  opacity: 0;
  transition: opacity var(--transition);
}

.cert-card:hover .cert-ribbon { opacity: 1; }

.cert-icon { font-size: 1.8rem; }

.cert-body { flex: 1; }

.cert-body h4 {
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--navy);
  margin-bottom: 6px;
  line-height: 1.4;
}

.cert-issuer {
  font-size: 0.78rem;
  color: var(--text-light);
  font-weight: 500;
}

.cert-badge {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  background: rgba(20,168,107,0.1);
  color: var(--emerald);
  padding: 3px 10px;
  border-radius: 20px;
  align-self: flex-start;
}

.cert-link {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--emerald);
  background: rgba(20,168,107,0.08);
  border: 1px solid rgba(20,168,107,0.2);
  padding: 6px 14px;
  border-radius: 6px;
  align-self: flex-start;
  transition: all var(--transition);
}

.cert-link:hover {
  background: var(--emerald);
  color: var(--white);
  border-color: var(--emerald);
  transform: translateY(-1px);
}

/* ============================================================
   CONTACT
   ============================================================ */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1.6fr;
  gap: 50px;
  align-items: start;
}

.contact-info-panel {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.ci-item {
  display: flex;
  align-items: flex-start;
  gap: 16px;
}

.ci-icon {
  width: 44px; height: 44px;
  background: rgba(20,168,107,0.12);
  border-radius: 10px;
  display: grid;
  place-items: center;
  font-size: 1.1rem;
  flex-shrink: 0;
}

.ci-label {
  display: block;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  color: rgba(255,255,255,0.5);
  margin-bottom: 4px;
}

.ci-value {
  font-size: 0.9rem;
  color: rgba(255,255,255,0.85);
  transition: color var(--transition);
}
a.ci-value:hover { color: var(--emerald-light); }

/* Contact Form */
.contact-form {
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: var(--radius-lg);
  padding: 36px;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: 16px;
}

.form-group label {
  font-size: 0.82rem;
  font-weight: 600;
  color: rgba(255,255,255,0.7);
  letter-spacing: 0.3px;
}

.form-group input,
.form-group textarea {
  background: rgba(255,255,255,0.07);
  border: 1px solid rgba(255,255,255,0.15);
  border-radius: 8px;
  padding: 12px 16px;
  color: var(--white);
  font-size: 0.92rem;
  font-family: 'Inter', sans-serif;
  transition: all var(--transition);
  resize: vertical;
}

.form-group input::placeholder,
.form-group textarea::placeholder { color: rgba(255,255,255,0.3); }

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--emerald);
  background: rgba(20,168,107,0.07);
}

.form-status {
  margin-top: 14px;
  padding: 10px 16px;
  border-radius: 8px;
  font-size: 0.88rem;
  display: none;
}

.form-status.success {
  display: block;
  background: rgba(20,168,107,0.15);
  color: var(--emerald-light);
  border: 1px solid rgba(20,168,107,0.3);
}

.form-status.error {
  display: block;
  background: rgba(220,38,38,0.15);
  color: #fca5a5;
  border: 1px solid rgba(220,38,38,0.3);
}

/* ============================================================
   FOOTER
   ============================================================ */
.footer { background: #060f1a; padding: 60px 0 0; }

.footer-inner {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr;
  gap: 40px;
  padding-bottom: 40px;
  border-bottom: 1px solid rgba(255,255,255,0.08);
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-name {
  font-family: 'Poppins', sans-serif;
  font-size: 1rem;
  font-weight: 600;
  color: rgba(255,255,255,0.9);
}

.footer-tagline {
  font-size: 0.82rem;
  color: rgba(255,255,255,0.45);
  line-height: 1.5;
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-links a {
  font-size: 0.88rem;
  color: rgba(255,255,255,0.55);
  transition: color var(--transition);
}
.footer-links a:hover { color: var(--emerald-light); }

.footer-social {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.social-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 1.2rem;
  color: rgba(255,255,255,0.55);
  transition: color var(--transition);
}
.social-link:hover { color: var(--emerald-light); }

.footer-bottom {
  padding: 20px 0;
  text-align: center;
}

.footer-bottom p {
  font-size: 0.8rem;
  color: rgba(255,255,255,0.3);
}

/* ============================================================
   BACK TO TOP
   ============================================================ */
.back-to-top {
  position: fixed;
  bottom: 28px;
  right: 28px;
  width: 46px; height: 46px;
  background: var(--emerald);
  color: white;
  border: none;
  border-radius: 50%;
  font-size: 1.4rem;
  cursor: pointer;
  opacity: 0;
  pointer-events: none;
  transform: translateY(16px);
  transition: all var(--transition);
  box-shadow: var(--shadow-md);
  z-index: 999;
  display: grid;
  place-items: center;
}

.back-to-top.visible {
  opacity: 1;
  pointer-events: all;
  transform: translateY(0);
}

.back-to-top:hover { background: var(--deep-green); transform: translateY(-2px); }

/* ============================================================
   SCROLL ANIMATIONS
   ============================================================ */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.65s ease, transform 0.65s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: none;
}

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 1100px) {
  .skills-grid { grid-template-columns: repeat(3, 1fr); }
  .certs-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 900px) {
  .hero-inner { grid-template-columns: 1fr; text-align: center; }
  .hero-buttons { justify-content: center; }
  .hero-avatar-side { order: -1; }
  .hero-photo-ring { width: 180px; height: 180px; }
  .hero-stats-grid { max-width: 380px; margin: 0 auto; }
  .about-grid { grid-template-columns: 1fr; }
  .pubs-grid { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
  .footer-inner { grid-template-columns: 1fr 1fr; }
  .skills-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .section { padding: 72px 0; }
  .section-title { font-size: 1.9rem; }

  .hamburger { display: flex; }

  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0; right: 0;
    background: var(--navy);
    flex-direction: column;
    padding: 16px;
    gap: 4px;
    box-shadow: var(--shadow-lg);
  }
  .nav-links.open { display: flex; }
  .nav-link { padding: 12px 16px; width: 100%; }

  .hero-name { font-size: 2.5rem; }
  .hero-photo-ring { width: 140px; height: 140px; }

  .tl-header { flex-direction: column; gap: 10px; }
  .tl-meta { text-align: left; }

  .proj-pdf-area { height: 320px; }
  .proj-pdf-overlay {
    background: rgba(11,31,51,0.5);
    pointer-events: all;
  }
  .pdf-open-btn { opacity: 1; transform: none; }

  .proj-highlights { grid-template-columns: 1fr; }
  .certs-grid { grid-template-columns: 1fr 1fr; }
  .skills-grid { grid-template-columns: 1fr 1fr; }
  .rdir-grid { grid-template-columns: 1fr 1fr; }

  .form-row { grid-template-columns: 1fr; }
  .contact-form { padding: 24px; }
  .footer-inner { grid-template-columns: 1fr; gap: 28px; }

  .research-focus-block { flex-direction: column; gap: 14px; padding: 24px; }
}

@media (max-width: 480px) {
  .hero-buttons { flex-direction: column; align-items: center; }
  .hero-stats-grid { grid-template-columns: 1fr 1fr; }
  .proj-pdf-area { height: 240px; }
  .certs-grid { grid-template-columns: 1fr; }
  .skills-grid { grid-template-columns: 1fr; }
  .rdir-grid { grid-template-columns: 1fr; }
}