/*
Theme Name: Samuel Kporvie Portfolio
Theme URI: https://github.com/samuelselasi
Author: Samuel Selasi Kporvie
Author URI: https://github.com/samuelselasi
Description: A sophisticated, minimalist Tech-Academic portfolio theme for Quantitative Researcher and Computer Science Expert Samuel Selasi Kporvie. Features Navy, Slate Grey, and Emerald Green palette with Serif and Monospace typography.
Version: 1.0.0
License: GNU General Public License v2 or later
License URI: http://www.gnu.org/licenses/gpl-2.0.html
Text Domain: samuel-portfolio
Tags: portfolio, one-page, academic, research, minimalist
*/

/* ============================================================
   CSS CUSTOM PROPERTIES
   ============================================================ */
:root {
  --navy:         #0D1B2A;
  --navy-mid:     #162439;
  --navy-light:   #1E3553;
  --slate:        #4A5568;
  --slate-light:  #718096;
  --emerald:      #059669;
  --emerald-mid:  #10B981;
  --emerald-glow: rgba(5, 150, 105, 0.15);
  --white:        #FFFFFF;
  --off-white:    #F7F8FA;
  --mist:         #EDF2F7;
  --border:       rgba(74, 85, 104, 0.15);
  --border-dark:  rgba(255,255,255,0.08);

  --font-serif:   'Playfair Display', Georgia, 'Times New Roman', serif;
  --font-mono:    'JetBrains Mono', 'Fira Code', 'Courier New', monospace;
  --font-body:    'Source Serif 4', Georgia, serif;

  --radius:       4px;
  --radius-lg:    8px;
  --transition:   0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --shadow-sm:    0 1px 3px rgba(13,27,42,0.08), 0 1px 2px rgba(13,27,42,0.06);
  --shadow-md:    0 4px 16px rgba(13,27,42,0.10), 0 2px 6px rgba(13,27,42,0.06);
  --shadow-lg:    0 20px 40px rgba(13,27,42,0.15), 0 8px 16px rgba(13,27,42,0.08);
}

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

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

body {
  font-family: var(--font-body);
  background: var(--white);
  color: var(--slate);
  line-height: 1.75;
  overflow-x: hidden;
}

a { color: inherit; text-decoration: none; }
a:hover { color: var(--emerald); }
img { max-width: 100%; height: auto; display: block; }
ul { list-style: none; }

/* ============================================================
   TYPOGRAPHY SCALE
   ============================================================ */
h1, h2, h3, h4, h5 {
  font-family: var(--font-serif);
  color: var(--navy);
  line-height: 1.2;
  font-weight: 700;
}

h1 { font-size: clamp(2.6rem, 5vw, 4.2rem); letter-spacing: -0.02em; }
h2 { font-size: clamp(1.8rem, 3vw, 2.6rem); letter-spacing: -0.01em; }
h3 { font-size: clamp(1.2rem, 2vw, 1.6rem); }
h4 { font-size: 1.1rem; font-weight: 600; }

p { color: var(--slate); font-size: 1.0625rem; line-height: 1.8; }

.mono {
  font-family: var(--font-mono);
  font-size: 0.85em;
  letter-spacing: 0.03em;
}

/* ============================================================
   LAYOUT HELPERS
   ============================================================ */
.container {
  width: 100%;
  max-width: 1160px;
  margin: 0 auto;
  padding: 0 2rem;
}

.container--narrow {
  max-width: 780px;
  margin: 0 auto;
  padding: 0 2rem;
}

.section {
  padding: 6rem 0;
}

.section--alt {
  background: var(--off-white);
}

.section--dark {
  background: var(--navy);
  color: var(--white);
}

.section--dark h2,
.section--dark h3,
.section--dark h4 {
  color: var(--white);
}

.section--dark p {
  color: rgba(255,255,255,0.75);
}

.section-label {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--emerald);
  display: block;
  margin-bottom: 0.75rem;
  font-weight: 500;
}

.section-title {
  margin-bottom: 0.5rem;
}

.section-intro {
  font-size: 1.1rem;
  color: var(--slate-light);
  max-width: 600px;
  margin-bottom: 3.5rem;
}

.divider {
  width: 48px;
  height: 3px;
  background: var(--emerald);
  margin: 1.25rem 0 2rem;
  border-radius: 2px;
}

/* ============================================================
   NAVIGATION
   ============================================================ */
.site-nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  background: rgba(13, 27, 42, 0.97);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-dark);
  transition: var(--transition);
}

.site-nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.site-nav__logo {
  font-family: var(--font-serif);
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--white);
  letter-spacing: -0.01em;
}

.site-nav__logo span {
  color: var(--emerald);
}

.site-nav__links {
  display: flex;
  gap: 2rem;
  align-items: center;
}

.site-nav__links a {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.65);
  transition: color var(--transition);
  padding: 0.25rem 0;
  border-bottom: 2px solid transparent;
}

.site-nav__links a:hover,
.site-nav__links a.active {
  color: var(--white);
  border-color: var(--emerald);
}

.site-nav__cta {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--emerald) !important;
  border: 1px solid var(--emerald) !important;
  border-bottom: 1px solid var(--emerald) !important;
  padding: 0.45rem 1.1rem !important;
  border-radius: var(--radius);
  transition: background var(--transition), color var(--transition) !important;
}

.site-nav__cta:hover {
  background: var(--emerald) !important;
  color: var(--white) !important;
}

.nav-hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 4px;
}

.nav-hamburger span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--white);
  border-radius: 2px;
  transition: var(--transition);
}

/* ============================================================
   HERO SECTION
   ============================================================ */
.hero {
  min-height: 100vh;
  background: var(--navy);
  display: flex;
  align-items: center;
  position: relative;
  overflow: hidden;
  padding-top: 64px;
}

.hero__bg {
  position: absolute;
  inset: 0;
  overflow: hidden;
  pointer-events: none;
}

/* Subtle grid pattern */
.hero__bg::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(5,150,105,0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(5,150,105,0.04) 1px, transparent 1px);
  background-size: 60px 60px;
  mask-image: radial-gradient(ellipse 80% 60% at 50% 50%, black, transparent);
}

/* Radial glow */
.hero__bg::after {
  content: '';
  position: absolute;
  top: 20%;
  right: -10%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(5,150,105,0.06) 0%, transparent 70%);
  border-radius: 50%;
}

.hero__content {
  position: relative;
  z-index: 2;
  padding: 5rem 0 4rem;
}

.hero__tag {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--emerald);
  background: rgba(5,150,105,0.1);
  border: 1px solid rgba(5,150,105,0.25);
  border-radius: 100px;
  padding: 0.4rem 1rem;
  margin-bottom: 1.75rem;
}

.hero__tag::before {
  content: '';
  display: inline-block;
  width: 6px;
  height: 6px;
  background: var(--emerald);
  border-radius: 50%;
  animation: pulse-dot 2s ease-in-out infinite;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(0.7); }
}

.hero__name {
  font-family: var(--font-serif);
  font-size: clamp(3rem, 7vw, 5.5rem);
  font-weight: 700;
  color: var(--white);
  line-height: 1.05;
  letter-spacing: -0.03em;
  margin-bottom: 0.35rem;
}

.hero__name em {
  font-style: normal;
  color: var(--emerald-mid);
}

.hero__title {
  font-family: var(--font-mono);
  font-size: clamp(0.85rem, 1.5vw, 1rem);
  letter-spacing: 0.12em;
  color: rgba(255,255,255,0.45);
  text-transform: uppercase;
  margin-bottom: 2rem;
}

.hero__title span {
  color: rgba(255,255,255,0.75);
}

.hero__statement {
  font-size: clamp(1rem, 1.5vw, 1.175rem);
  color: rgba(255,255,255,0.72);
  max-width: 600px;
  line-height: 1.85;
  margin-bottom: 2.5rem;
}

.hero__statement strong {
  color: rgba(255,255,255,0.95);
  font-weight: 600;
}

.hero__actions {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 4rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 0.75rem 1.75rem;
  border-radius: var(--radius);
  transition: var(--transition);
  cursor: pointer;
  border: none;
  font-weight: 500;
}

.btn--primary {
  background: var(--emerald);
  color: var(--white);
}

.btn--primary:hover {
  background: var(--emerald-mid);
  color: var(--white);
  transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(5,150,105,0.35);
}

.btn--outline {
  background: transparent;
  color: rgba(255,255,255,0.8);
  border: 1px solid rgba(255,255,255,0.2);
}

.btn--outline:hover {
  background: rgba(255,255,255,0.06);
  color: var(--white);
  border-color: rgba(255,255,255,0.4);
  transform: translateY(-1px);
}

.hero__stats {
  display: grid;
  grid-template-columns: repeat(4, auto);
  gap: 2.5rem;
  width: fit-content;
  border-top: 1px solid rgba(255,255,255,0.08);
  padding-top: 2.5rem;
}

.hero__stat-value {
  font-family: var(--font-serif);
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--white);
  display: block;
  line-height: 1;
  margin-bottom: 0.3rem;
}

.hero__stat-value span {
  color: var(--emerald-mid);
}

.hero__stat-label {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.4);
}

/* Hero decorative right panel */
.hero__visual {
  position: absolute;
  right: 0;
  top: 64px;
  bottom: 0;
  width: 42%;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.hero__terminal {
  width: 420px;
  background: rgba(255,255,255,0.03);
  border: 1px solid rgba(255,255,255,0.07);
  border-radius: var(--radius-lg);
  overflow: hidden;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  backdrop-filter: blur(8px);
}

.hero__terminal-bar {
  background: rgba(255,255,255,0.05);
  padding: 0.7rem 1rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  border-bottom: 1px solid rgba(255,255,255,0.06);
}

.terminal-dot {
  width: 10px; height: 10px;
  border-radius: 50%;
}
.terminal-dot--red   { background: #FF5F56; }
.terminal-dot--yellow{ background: #FFBD2E; }
.terminal-dot--green { background: #27C93F; }

.hero__terminal-title {
  font-size: 0.7rem;
  color: rgba(255,255,255,0.3);
  letter-spacing: 0.06em;
  margin-left: auto;
}

.hero__terminal-body {
  padding: 1.25rem 1.25rem 1.5rem;
  line-height: 1.9;
}

.t-line { display: block; }
.t-prompt { color: var(--emerald); }
.t-key   { color: rgba(255,255,255,0.5); }
.t-val   { color: rgba(255,255,255,0.85); }
.t-str   { color: #93C5FD; }
.t-num   { color: #FCA5A5; }
.t-dim   { color: rgba(255,255,255,0.28); font-size: 0.75rem; }
.t-blank { display: block; height: 0.4rem; }
.t-cursor::after {
  content: '▋';
  animation: blink 1.2s step-end infinite;
  color: var(--emerald);
}
@keyframes blink { 0%,100%{opacity:1} 50%{opacity:0} }

/* ============================================================
   RESEARCH PILLARS (3-COLUMN)
   ============================================================ */
.pillars-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.pillar {
  background: var(--white);
  padding: 2.75rem 2.25rem;
  position: relative;
  transition: var(--transition);
}

.pillar:hover {
  background: var(--navy);
}

.pillar:hover .pillar__icon { color: var(--emerald-mid); background: rgba(5,150,105,0.12); }
.pillar:hover .pillar__num  { color: rgba(255,255,255,0.1); }
.pillar:hover h3            { color: var(--white); }
.pillar:hover p             { color: rgba(255,255,255,0.68); }
.pillar:hover .pillar__tags .tag { background: rgba(5,150,105,0.12); color: var(--emerald-mid); border-color: rgba(5,150,105,0.2); }

.pillar__num {
  position: absolute;
  top: 1.75rem;
  right: 2rem;
  font-family: var(--font-serif);
  font-size: 5rem;
  font-weight: 700;
  color: var(--mist);
  line-height: 1;
  transition: var(--transition);
  user-select: none;
}

.pillar__icon {
  width: 48px; height: 48px;
  background: var(--off-white);
  border-radius: var(--radius);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.35rem;
  margin-bottom: 1.5rem;
  color: var(--slate);
  transition: var(--transition);
}

.pillar h3 {
  font-size: 1.25rem;
  margin-bottom: 1rem;
  transition: var(--transition);
}

.pillar p {
  font-size: 0.95rem;
  line-height: 1.75;
  margin-bottom: 1.5rem;
  transition: var(--transition);
}

.pillar__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.tag {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.04em;
  padding: 0.3rem 0.65rem;
  border: 1px solid var(--border);
  border-radius: 100px;
  color: var(--slate);
  background: var(--off-white);
  transition: var(--transition);
}

/* ============================================================
   PROJECTS PORTFOLIO
   ============================================================ */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
}

.project-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 2.25rem;
  position: relative;
  overflow: hidden;
  transition: var(--transition);
  display: flex;
  flex-direction: column;
}

.project-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--emerald), var(--emerald-mid));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition);
}

.project-card:hover {
  border-color: rgba(5,150,105,0.25);
  box-shadow: var(--shadow-md);
  transform: translateY(-3px);
}

.project-card:hover::before {
  transform: scaleX(1);
}

.project-card--featured {
  grid-column: span 2;
  background: var(--navy);
  border-color: rgba(255,255,255,0.06);
  flex-direction: row;
  align-items: flex-start;
  gap: 3rem;
}

.project-card--featured::before {
  transform: scaleX(1);
}

.project-card--featured h3,
.project-card--featured h4 { color: var(--white); }
.project-card--featured p  { color: rgba(255,255,255,0.68); }

.project-card__badge {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  padding: 0.2rem 0.65rem;
  border-radius: 100px;
  margin-bottom: 1rem;
}

.badge--emerald {
  background: var(--emerald-glow);
  color: var(--emerald);
  border: 1px solid rgba(5,150,105,0.2);
}

.badge--navy {
  background: var(--navy);
  color: rgba(255,255,255,0.65);
  border: 1px solid rgba(255,255,255,0.1);
}

.badge--white {
  background: rgba(255,255,255,0.08);
  color: rgba(255,255,255,0.75);
  border: 1px solid rgba(255,255,255,0.12);
}

.project-card h3 {
  font-size: 1.2rem;
  margin-bottom: 0.75rem;
}

.project-card p {
  font-size: 0.95rem;
  flex: 1;
  margin-bottom: 1.5rem;
}

.project-card__meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: auto;
  padding-top: 1.25rem;
  border-top: 1px solid var(--border);
}

.project-card--featured .project-card__meta {
  border-color: rgba(255,255,255,0.08);
}

.project-card__year {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--slate-light);
  letter-spacing: 0.06em;
}

.project-card--featured .project-card__year {
  color: rgba(255,255,255,0.35);
}

.project-card__link {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  color: var(--emerald);
  display: flex;
  align-items: center;
  gap: 0.35rem;
  transition: gap var(--transition);
}

.project-card__link:hover {
  gap: 0.6rem;
  color: var(--emerald-mid);
}

.project-card__body { flex: 1; }

/* Featured card special layout */
.project-card--featured .project-card__badge-wrap { min-width: 200px; }
.project-card--featured .project-card__stat {
  margin-top: 1.75rem;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.stat-item {
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.06);
  border-radius: var(--radius);
  padding: 0.85rem 1rem;
}

.stat-item__val {
  font-family: var(--font-serif);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--white);
  line-height: 1;
  display: block;
  margin-bottom: 0.2rem;
}

.stat-item__val span { color: var(--emerald-mid); }

.stat-item__key {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.35);
}

/* ============================================================
   TECHNICAL STACK
   ============================================================ */
.stack-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
  margin-bottom: 2.5rem;
}

.stack-category {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  transition: var(--transition);
}

.stack-category:hover {
  border-color: rgba(5,150,105,0.3);
  box-shadow: var(--shadow-sm);
}

.stack-category__label {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--emerald);
  margin-bottom: 1rem;
  display: block;
}

.stack-items {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.stack-item {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--navy);
  padding: 0.35rem 0.65rem;
  background: var(--off-white);
  border-radius: var(--radius);
  letter-spacing: 0.02em;
  transition: var(--transition);
}

.stack-item:hover {
  background: var(--emerald-glow);
  color: var(--emerald);
}

/* ============================================================
   PUBLICATIONS
   ============================================================ */
.publications-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.publication-item {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: start;
  gap: 1.5rem;
  padding: 1.5rem 2rem;
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  transition: var(--transition);
}

.publication-item:hover {
  border-color: rgba(5,150,105,0.25);
  transform: translateX(4px);
  box-shadow: var(--shadow-sm);
}

.publication-item__num {
  font-family: var(--font-serif);
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--mist);
  line-height: 1.2;
  user-select: none;
  min-width: 32px;
}

.publication-item__title {
  font-family: var(--font-serif);
  font-size: 1rem;
  font-weight: 600;
  color: var(--navy);
  margin-bottom: 0.35rem;
  line-height: 1.4;
}

.publication-item__meta {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--slate-light);
  letter-spacing: 0.03em;
}

.pub-status {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: 0.25rem 0.65rem;
  border-radius: 100px;
  white-space: nowrap;
  align-self: center;
}

.pub-status--review {
  background: rgba(251,191,36,0.1);
  color: #D97706;
  border: 1px solid rgba(251,191,36,0.2);
}

.pub-status--published {
  background: var(--emerald-glow);
  color: var(--emerald);
  border: 1px solid rgba(5,150,105,0.2);
}

/* ============================================================
   EXPERIENCE & EDUCATION TIMELINE
   ============================================================ */
.timeline {
  position: relative;
  padding-left: 2.5rem;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 8px;
  top: 8px;
  bottom: 0;
  width: 1px;
  background: linear-gradient(to bottom, var(--emerald), rgba(5,150,105,0.1));
}

.timeline-item {
  position: relative;
  margin-bottom: 2.5rem;
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: -2.5rem;
  top: 6px;
  width: 14px; height: 14px;
  border-radius: 50%;
  background: var(--white);
  border: 2px solid var(--emerald);
  transition: var(--transition);
}

.timeline-item:hover::before {
  background: var(--emerald);
  box-shadow: 0 0 0 4px var(--emerald-glow);
}

.timeline-item__period {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--emerald);
  margin-bottom: 0.4rem;
}

.timeline-item__role {
  font-family: var(--font-serif);
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--navy);
  margin-bottom: 0.2rem;
}

.timeline-item__org {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--slate-light);
  margin-bottom: 0.85rem;
  letter-spacing: 0.03em;
}

.timeline-item__desc {
  font-size: 0.95rem;
  color: var(--slate);
  line-height: 1.75;
}

.timeline-item__tools {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-top: 0.85rem;
}

/* ============================================================
   CERTIFICATIONS
   ============================================================ */
.certs-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
}

.cert-card {
  background: var(--navy-light);
  border: 1px solid rgba(255,255,255,0.07);
  border-radius: var(--radius-lg);
  padding: 2rem 2rem;
  display: flex;
  align-items: flex-start;
  gap: 1.25rem;
  transition: var(--transition);
}

.cert-card:hover {
  border-color: rgba(5,150,105,0.3);
  transform: translateY(-2px);
}

.cert-card__icon {
  width: 44px; height: 44px;
  background: var(--emerald-glow);
  border: 1px solid rgba(5,150,105,0.25);
  border-radius: var(--radius);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.25rem;
  flex-shrink: 0;
  color: var(--emerald-mid);
}

.cert-card h4 {
  color: var(--white);
  font-size: 0.95rem;
  margin-bottom: 0.3rem;
  line-height: 1.35;
}

.cert-card p {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: rgba(255,255,255,0.4);
  letter-spacing: 0.06em;
}

/* ============================================================
   CONTACT / FOOTER
   ============================================================ */
.contact {
  background: var(--navy);
  padding: 6rem 0 3rem;
}

.contact-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 5rem;
  margin-bottom: 4rem;
}

.contact__heading {
  font-size: clamp(2rem, 3.5vw, 3rem);
  color: var(--white);
  margin-bottom: 1rem;
  line-height: 1.15;
}

.contact__sub {
  color: rgba(255,255,255,0.6);
  font-size: 1rem;
  margin-bottom: 2.25rem;
}

.contact__links {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.contact__link {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem 1.25rem;
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.07);
  border-radius: var(--radius);
  transition: var(--transition);
  color: rgba(255,255,255,0.75);
  font-size: 0.9rem;
}

.contact__link:hover {
  background: rgba(5,150,105,0.08);
  border-color: rgba(5,150,105,0.25);
  color: var(--white);
  transform: translateX(4px);
}

.contact__link-icon {
  width: 36px; height: 36px;
  background: rgba(255,255,255,0.05);
  border-radius: var(--radius);
  display: flex; align-items: center; justify-content: center;
  font-size: 1rem;
  flex-shrink: 0;
}

.contact__availability {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--emerald);
  background: rgba(5,150,105,0.1);
  border: 1px solid rgba(5,150,105,0.2);
  border-radius: 100px;
  padding: 0.45rem 1rem;
  margin-bottom: 1.75rem;
}

.contact__availability::before {
  content: '';
  width: 6px; height: 6px;
  background: var(--emerald);
  border-radius: 50%;
  animation: pulse-dot 2s ease-in-out infinite;
}

.site-footer {
  border-top: 1px solid rgba(255,255,255,0.06);
  padding-top: 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.footer-copy {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  color: rgba(255,255,255,0.3);
}

.footer-copy a {
  color: rgba(255,255,255,0.5);
}

.footer-social {
  display: flex;
  gap: 0.75rem;
}

.footer-social a {
  width: 32px; height: 32px;
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.07);
  border-radius: var(--radius);
  display: flex; align-items: center; justify-content: center;
  font-size: 0.85rem;
  color: rgba(255,255,255,0.45);
  transition: var(--transition);
}

.footer-social a:hover {
  background: var(--emerald-glow);
  border-color: rgba(5,150,105,0.25);
  color: var(--emerald-mid);
}

/* ============================================================
   SCROLL ANIMATIONS
   ============================================================ */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.7s cubic-bezier(0.4,0,0.2,1), transform 0.7s cubic-bezier(0.4,0,0.2,1);
}

.reveal.visible {
  opacity: 1;
  transform: none;
}

.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }
.reveal-delay-4 { transition-delay: 0.4s; }

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 1024px) {
  .hero__visual { display: none; }
  .stack-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .site-nav__links { display: none; }
  .nav-hamburger { display: flex; }
  .site-nav__links.open {
    display: flex;
    flex-direction: column;
    position: fixed;
    top: 64px; left: 0; right: 0;
    background: var(--navy);
    padding: 1.5rem 2rem;
    gap: 1.25rem;
    border-top: 1px solid rgba(255,255,255,0.06);
  }
  .pillars-grid { grid-template-columns: 1fr; }
  .projects-grid { grid-template-columns: 1fr; }
  .project-card--featured { grid-column: span 1; flex-direction: column; gap: 1.5rem; }
  .certs-grid { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: 1fr; gap: 3rem; }
  .hero__stats { grid-template-columns: repeat(2, 1fr); gap: 1.5rem; }
  .stack-grid { grid-template-columns: 1fr; }
  .publication-item { grid-template-columns: auto 1fr; }
  .pub-status { grid-column: 2; }
  .site-footer { flex-direction: column; gap: 1rem; text-align: center; }
}

@media (max-width: 480px) {
  .container { padding: 0 1.25rem; }
  .section { padding: 4rem 0; }
  .hero__actions { flex-direction: column; }
  .btn { width: 100%; justify-content: center; }
}

/* ============================================================
   PRINT
   ============================================================ */
@media print {
  .site-nav, .hero__visual { display: none; }
  .hero { min-height: auto; padding: 2rem 0; }
  .reveal { opacity: 1; transform: none; }
}