/* ==========================================================================
   Richard Jensen - Academic Website Design System
   Modern, responsive, professional stylesheet using British English conventions.
   Uses dvh units for viewport calculations across iOS, Android, and Windows.
   ========================================================================== */

:root {
  /* Colour Palette */
  --primary: #0f2b48;
  --primary-light: #1e3f66;
  --primary-dark: #081a2e;
  --accent: #0284c7;
  --accent-hover: #0369a1;
  --accent-subtle: #e0f2fe;
  --accent-text: #0369a1;
  --gold: #b45309;
  --gold-subtle: #fef3c7;
  --gold-text: #92400e;
  
  --bg: #f8fafc;
  --bg-alt: #f1f5f9;
  --surface: #ffffff;
  --surface-alt: #f8fafc;
  --border: #e2e8f0;
  --border-focus: #94a3b8;
  
  --text: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;
  --text-light: #94a3b8;
  --text-inverse: #ffffff;
  
  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-heading: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
  
  /* Elevation & Shadows */
  --shadow-xs: 0 1px 2px rgba(15, 23, 42, 0.05);
  --shadow-sm: 0 2px 4px rgba(15, 23, 42, 0.06);
  --shadow-md: 0 4px 12px rgba(15, 23, 42, 0.08);
  --shadow-lg: 0 12px 24px -4px rgba(15, 23, 42, 0.1);
  --shadow-xl: 0 20px 30px -6px rgba(15, 23, 42, 0.12);
  
  /* Layout & Sizing */
  --header-height: 72px;
  --container-max: 1200px;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-full: 9999px;
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
}

/* Base Reset & Box Sizing */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  background-color: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

main {
  flex: 1 0 auto;
}

img, video, canvas {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--accent-hover);
  text-decoration: underline;
}

h1, h2, h3, h4, h5, h6 {
  color: var(--primary);
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: 1.25;
  letter-spacing: -0.02em;
}

h1 { font-size: 2.25rem; margin-bottom: 1rem; }
h2 { font-size: 1.75rem; margin-bottom: 0.85rem; }
h3 { font-size: 1.35rem; margin-bottom: 0.65rem; }
h4 { font-size: 1.15rem; margin-bottom: 0.5rem; }

p {
  margin-bottom: 1rem;
}

p:last-child {
  margin-bottom: 0;
}

ul, ol {
  margin-bottom: 1rem;
  padding-left: 1.5rem;
}

li {
  margin-bottom: 0.35rem;
}

code, pre {
  font-family: var(--font-mono);
  font-size: 0.9em;
}

/* ==========================================================================
   Header & Navigation
   ========================================================================== */

.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: rgba(255, 255, 255, 0.96);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow-xs);
  height: var(--header-height);
}

.header-inner {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 1.5rem;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  display: flex;
  flex-direction: column;
  text-decoration: none;
}

.brand-name {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--primary);
  letter-spacing: -0.01em;
}

.brand-title {
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--text-muted);
}

.brand:hover {
  text-decoration: none;
}

.brand:hover .brand-name {
  color: var(--accent);
}

/* Desktop Navigation */
.nav-menu {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-link {
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--text-secondary);
  padding: 0.55rem 0.85rem;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
}

.nav-link:hover {
  color: var(--primary);
  background-color: var(--bg-alt);
  text-decoration: none;
}

.nav-link.active {
  color: var(--primary);
  background-color: var(--accent-subtle);
  font-weight: 600;
}

/* Mobile Navigation Toggle Button */
.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.5rem;
  cursor: pointer;
  color: var(--primary);
  align-items: center;
  justify-content: center;
}

.nav-toggle:focus-visible {
  outline: 2px solid var(--accent);
}

/* ==========================================================================
   Containers & Common Layout
   ========================================================================== */

.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 2.5rem 1.5rem;
}

.section-header {
  margin-bottom: 2rem;
  position: relative;
}

.section-header p {
  color: var(--text-secondary);
  font-size: 1.05rem;
  max-width: 750px;
}

.page-title-banner {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
  color: var(--text-inverse);
  padding: 3rem 1.5rem;
  border-bottom: 1px solid var(--border);
}

.page-title-banner .container {
  padding: 0;
}

.page-title-banner h1 {
  color: var(--text-inverse);
  margin-bottom: 0.5rem;
}

.page-title-banner p {
  color: #cbd5e1;
  font-size: 1.15rem;
  max-width: 800px;
}

.page-breadcrumbs {
  font-size: 0.85rem;
  color: #94a3b8;
  margin-bottom: 0.75rem;
}

.page-breadcrumbs a {
  color: #e2e8f0;
  text-decoration: none;
}

.page-breadcrumbs a:hover {
  text-decoration: underline;
}

/* ==========================================================================
   Profile Hero (Homepage)
   ========================================================================== */

.hero-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 2.5rem;
  box-shadow: var(--shadow-sm);
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 2.5rem;
  align-items: center;
  margin-bottom: 3rem;
}

.hero-avatar-wrap {
  text-align: center;
}

.hero-avatar {
  width: 190px;
  height: auto;
  aspect-ratio: 418 / 570;
  max-height: 250px;
  border-radius: var(--radius-lg);
  object-fit: cover;
  object-position: top center;
  border: 3px solid var(--surface);
  box-shadow: var(--shadow-md);
  margin: 0 auto 1rem;
}

.hero-meta-badges {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.hero-content h1 {
  font-size: 2.35rem;
  margin-bottom: 0.25rem;
}

.hero-role {
  font-size: 1.25rem;
  color: var(--accent);
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.hero-affiliation {
  font-size: 1rem;
  color: var(--text-secondary);
  margin-bottom: 1.25rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.hero-bio {
  font-size: 1.05rem;
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
  line-height: 1.7;
}

.hero-links {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

/* ==========================================================================
   Buttons & Badges
   ========================================================================== */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.65rem 1.25rem;
  font-size: 0.92rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
  line-height: 1;
}

.btn:hover {
  text-decoration: none;
}

.btn-primary {
  background-color: var(--primary);
  color: var(--text-inverse);
  border-color: var(--primary);
}

.btn-primary:hover {
  background-color: var(--primary-light);
  color: var(--text-inverse);
}

.btn-accent {
  background-color: var(--accent);
  color: var(--text-inverse);
}

.btn-accent:hover {
  background-color: var(--accent-hover);
  color: var(--text-inverse);
}

.btn-outline {
  background-color: transparent;
  border-color: var(--border);
  color: var(--text);
}

.btn-outline:hover {
  background-color: var(--bg-alt);
  border-color: var(--text-muted);
}

.btn-sm {
  padding: 0.4rem 0.75rem;
  font-size: 0.82rem;
  border-radius: var(--radius-sm);
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.25rem 0.65rem;
  border-radius: var(--radius-full);
  font-size: 0.78rem;
  font-weight: 600;
  line-height: 1;
}

.badge-primary {
  background-color: var(--accent-subtle);
  color: var(--accent-text);
}

.badge-gold {
  background-color: var(--gold-subtle);
  color: var(--gold-text);
  border: 1px solid rgba(180, 83, 9, 0.2);
}

.badge-neutral {
  background-color: var(--bg-alt);
  color: var(--text-secondary);
}

/* ==========================================================================
   Cards & Grids
   ========================================================================== */

.grid {
  display: grid;
  gap: 1.5rem;
}

.grid-cols-2 { grid-template-columns: repeat(2, 1fr); }
.grid-cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid-cols-4 { grid-template-columns: repeat(4, 1fr); }

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  box-shadow: var(--shadow-xs);
  transition: transform var(--transition-fast), box-shadow var(--transition-fast);
}

.card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.card-title {
  font-size: 1.2rem;
  color: var(--primary);
  margin-bottom: 0.5rem;
}

.card-subtitle {
  font-size: 0.88rem;
  color: var(--text-muted);
  margin-bottom: 0.85rem;
}

.card-description {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.6;
  margin-bottom: 1.25rem;
}

/* ==========================================================================
   Publications List & Filtering
   ========================================================================== */

.filter-bar {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 1rem 1.25rem;
  margin-bottom: 2rem;
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  align-items: center;
  justify-content: space-between;
  box-shadow: var(--shadow-xs);
}

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

.filter-tab {
  background: none;
  border: 1px solid transparent;
  padding: 0.45rem 0.9rem;
  border-radius: var(--radius-sm);
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.filter-tab:hover {
  background: var(--bg-alt);
  color: var(--primary);
}

.filter-tab.active {
  background: var(--primary);
  color: var(--text-inverse);
}

.search-box {
  position: relative;
  min-width: 260px;
  flex: 1;
  max-width: 380px;
}

.search-input {
  width: 100%;
  padding: 0.5rem 1rem 0.5rem 2.25rem;
  font-size: 0.88rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background-color: var(--bg);
  color: var(--text);
  outline: none;
  transition: border-color var(--transition-fast), background-color var(--transition-fast);
}

.search-input:focus {
  border-color: var(--accent);
  background-color: var(--surface);
}

.search-icon {
  position: absolute;
  left: 0.75rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
  pointer-events: none;
}

.publication-item {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.5rem;
  margin-bottom: 1rem;
  box-shadow: var(--shadow-xs);
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 1.25rem;
  align-items: flex-start;
  transition: all var(--transition-fast);
}

.publication-item:hover {
  border-color: var(--border-focus);
  box-shadow: var(--shadow-sm);
}

.pub-thumb {
  width: 58px;
  height: 80px;
  object-fit: cover;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: var(--bg-alt);
  box-shadow: var(--shadow-xs);
}

.pub-content {
  flex: 1;
}

.pub-header {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  margin-bottom: 0.35rem;
  flex-wrap: wrap;
}

.pub-year {
  font-weight: 700;
  font-size: 0.82rem;
  color: var(--primary);
  background: var(--bg-alt);
  padding: 0.15rem 0.5rem;
  border-radius: var(--radius-sm);
}

.pub-type-badge {
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.15rem 0.5rem;
  border-radius: var(--radius-sm);
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.pub-type-journal { background: #dbeafe; color: #1e40af; }
.pub-type-conference { background: #e0e7ff; color: #3730a3; }
.pub-type-chapter { background: #fef3c7; color: #92400e; }
.pub-type-book { background: #fce7f3; color: #9d174d; }

.pub-award {
  background: #fef3c7;
  color: #92400e;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 0.15rem 0.5rem;
  border-radius: var(--radius-sm);
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
}

.pub-title {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text);
  line-height: 1.4;
  margin-bottom: 0.4rem;
}

.pub-citation {
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.5;
  margin-bottom: 0.75rem;
}

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

/* ==========================================================================
   Book Feature Spotlight
   ========================================================================== */

.book-hero {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 2.5rem;
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 2.5rem;
  box-shadow: var(--shadow-sm);
  margin-bottom: 2.5rem;
}

.book-cover {
  width: 100%;
  max-width: 240px;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--border);
}

.book-details-list {
  list-style: none;
  padding: 0;
  margin: 1.25rem 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 0.75rem;
}

.book-detail-item {
  background: var(--bg);
  padding: 0.75rem 1rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
}

.book-detail-label {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-muted);
  font-weight: 600;
  display: block;
}

.book-detail-value {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--primary);
}

/* ==========================================================================
   Research & Media Showcases
   ========================================================================== */

.video-showcase {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
  box-shadow: var(--shadow-xs);
}

.video-container {
  background: #000;
  border-radius: var(--radius-sm);
  overflow: hidden;
  margin: 1rem 0;
}

.video-container video {
  width: 100%;
  max-height: 480px;
  display: block;
  margin: 0 auto;
}

/* Collapsible Years / Sections */
.accordion-item {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  margin-bottom: 0.75rem;
  overflow: hidden;
}

.accordion-trigger {
  width: 100%;
  text-align: left;
  background: none;
  border: none;
  padding: 1rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--primary);
  cursor: pointer;
  transition: background-color var(--transition-fast);
}

.accordion-trigger:hover {
  background-color: var(--bg-alt);
}

.accordion-icon {
  font-size: 0.9rem;
  transition: transform var(--transition-fast);
}

.accordion-item.open .accordion-icon {
  transform: rotate(180deg);
}

.accordion-content {
  display: none;
  padding: 0 1.25rem 1.25rem;
  border-top: 1px solid var(--border);
  background: var(--surface);
}

.accordion-item.open .accordion-content {
  display: block;
}

/* ==========================================================================
   Contact Cards
   ========================================================================== */

.contact-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
}

.contact-info-list {
  list-style: none;
  padding: 0;
  margin: 1.5rem 0;
}

.contact-info-item {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  padding: 0.85rem 0;
  border-bottom: 1px solid var(--border);
}

.contact-info-item:last-child {
  border-bottom: none;
}

.contact-icon {
  width: 38px;
  height: 38px;
  border-radius: var(--radius-sm);
  background: var(--accent-subtle);
  color: var(--accent);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.contact-label {
  font-size: 0.78rem;
  text-transform: uppercase;
  color: var(--text-muted);
  font-weight: 600;
  display: block;
}

.contact-val {
  font-size: 1.02rem;
  color: var(--text);
  font-weight: 500;
}

/* ==========================================================================
   Footer
   ========================================================================== */

.site-footer {
  background: var(--primary-dark);
  color: #94a3b8;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding: 3rem 1.5rem 2.5rem;
  margin-top: 4rem;
}

.footer-inner {
  max-width: var(--container-max);
  margin: 0 auto;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 2.5rem;
}

.footer-brand h3 {
  color: var(--text-inverse);
  font-size: 1.2rem;
  margin-bottom: 0.5rem;
}

.footer-brand p {
  color: #94a3b8;
  font-size: 0.9rem;
  max-width: 400px;
}

.footer-col h4 {
  color: var(--text-inverse);
  font-size: 0.95rem;
  margin-bottom: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.footer-nav {
  list-style: none;
  padding: 0;
  margin: 0;
}

.footer-nav li {
  margin-bottom: 0.5rem;
}

.footer-nav a {
  color: #cbd5e1;
  font-size: 0.9rem;
  text-decoration: none;
  transition: color var(--transition-fast);
}

.footer-nav a:hover {
  color: var(--text-inverse);
  text-decoration: underline;
}

/* ==========================================================================
   Responsive Breakpoints (Mobile, Tablet, Desktop)
   Works on iPad, Android, iPhone, Windows, macOS
   ========================================================================== */

@media (max-width: 992px) {
  .hero-card {
    grid-template-columns: 1fr;
    text-align: center;
    gap: 1.5rem;
  }
  
  .hero-affiliation {
    justify-content: center;
  }
  
  .hero-links {
    justify-content: center;
  }
  
  .grid-cols-4 { grid-template-columns: repeat(2, 1fr); }
  .grid-cols-3 { grid-template-columns: repeat(2, 1fr); }
  
  .book-hero {
    grid-template-columns: 1fr;
    text-align: center;
  }
  
  .book-cover {
    margin: 0 auto;
  }
  
  .contact-layout {
    grid-template-columns: 1fr;
  }
  
  .footer-inner {
    grid-template-columns: 1fr;
    gap: 2rem;
  }
}

@media (max-width: 768px) {
  :root {
    --header-height: 64px;
  }
  
  .nav-toggle {
    display: inline-flex;
  }
  
  .nav-menu {
    display: none;
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    align-items: stretch;
    padding: 1rem 1.5rem 1.5rem;
    box-shadow: var(--shadow-lg);
    gap: 0.5rem;
  }
  
  .nav-menu.open {
    display: flex;
  }
  
  .nav-link {
    padding: 0.75rem 1rem;
    font-size: 1rem;
  }
  
  .grid-cols-2 { grid-template-columns: 1fr; }
  .grid-cols-3 { grid-template-columns: 1fr; }
  
  .filter-bar {
    flex-direction: column;
    align-items: stretch;
  }
  
  .search-box {
    max-width: 100%;
  }
  
  .publication-item {
    grid-template-columns: 1fr;
  }
  
  .pub-thumb {
    display: none; /* Hide tiny thumb on small screens for cleaner density */
  }
}