/* ============================================================
   Personal Academic Website - style.css
   Assistant Professor | Smart Energy & Green Technology
   ============================================================
   Table of Contents:
   1.  CSS Variables & Reset
   2.  Typography
   3.  Navigation Bar
   4.  Section Base & Container
   5.  About Section
   6.  Research Section
   7.  Timeline (Experience)
   8.  Tabs (Projects)
   9.  Accordion (Publications)
   10. Cards (Talks / Invited Lectures)
   11. Media Coverage
   12. Teaching Section
   13. Contact & Footer
   14. Utility Classes
   15. Responsive Breakpoints
   16. Custom Scrollbar
   17. Language-specific Overrides
   18. Back to Top Button
   19. Project List & Publication List Styling
   20. Hamburger Menu Animation
   21. Committee List
   22. Missing HTML Class Aliases & Additional Styles
   23. Additional Responsive Overrides
   ============================================================ */


/* ==========================================================
   1. CSS Variables & Reset
   ========================================================== */

:root {
  /* Primary palette */
  --color-primary:       #1a365d;
  --color-primary-rgb:   26, 54, 93;
  --color-white:         #ffffff;
  --color-accent:        #2d8659;
  --color-accent-rgb:    45, 134, 89;

  /* Secondary palette */
  --color-light-blue:    #e8f0fe;
  --color-light-green:   #e6f4ea;
  --color-dark-text:     #1a202c;
  --color-gray:          #4a5568;
  --color-light-gray:    #f7fafc;
  --color-border:        #e2e8f0;
  --color-shadow:        rgba(0, 0, 0, 0.08);

  /* Typography */
  --font-primary:        'Inter', 'Noto Sans TC', 'Noto Sans JP', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-chinese:        'Noto Sans TC', 'Inter', sans-serif;
  --font-japanese:       'Noto Sans JP', 'Inter', sans-serif;
  --font-size-base:      16px;
  --line-height-base:    1.7;
  --line-height-heading: 1.3;

  /* Spacing */
  --spacing-xs:   4px;
  --spacing-sm:   8px;
  --spacing-md:   16px;
  --spacing-lg:   24px;
  --spacing-xl:   32px;
  --spacing-2xl:  48px;
  --spacing-3xl:  64px;
  --spacing-4xl:  80px;

  /* Layout */
  --container-max:  1200px;
  --container-pad:  20px;
  --nav-height:     70px;
  --border-radius:  8px;
  --border-radius-sm: 4px;
  --border-radius-lg: 12px;
  --border-radius-pill: 50px;

  /* Transitions */
  --transition-fast:   0.2s ease;
  --transition-base:   0.3s ease;
  --transition-slow:   0.6s ease;
}

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: var(--font-size-base);
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-primary);
  color: var(--color-dark-text);
  background-color: var(--color-white);
  line-height: var(--line-height-base);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

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

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

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

ul, ol {
  list-style: none;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}


/* ==========================================================
   2. Typography
   ========================================================== */

h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: var(--line-height-heading);
  color: var(--color-primary);
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem;   }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.1rem; }
h6 { font-size: 1rem;   }

p {
  margin-bottom: var(--spacing-md);
  color: var(--color-gray);
}

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

strong {
  font-weight: 600;
  color: var(--color-dark-text);
}


/* ==========================================================
   3. Navigation Bar
   ========================================================== */

.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: rgba(var(--color-primary-rgb), 0.85);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  z-index: 1000;
  transition: background var(--transition-base), box-shadow var(--transition-base);
}

.navbar.nav-scrolled {
  background: rgba(var(--color-primary-rgb), 1);
  box-shadow: 0 2px 20px rgba(0, 0, 0, 0.15);
}


/* Language Switcher */
.lang-switcher {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  flex-shrink: 0;
}


/* ==========================================================
   4. Section Base & Container
   ========================================================== */

.container {
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--container-pad);
  padding-right: var(--container-pad);
  overflow-wrap: break-word;
  word-break: break-word;
}

.section {
  padding: var(--spacing-4xl) 0;
}

.section:nth-child(even) {
  background-color: var(--color-light-gray);
}

.section:nth-child(odd) {
  background-color: var(--color-white);
}


/* ==========================================================
   5. About Section
   ========================================================== */

.about-grid {
  display: grid;
  grid-template-columns: 2fr 3fr;
  gap: var(--spacing-3xl);
  align-items: start;
  min-width: 0;
}

.about-text {
  min-width: 0;
  overflow-wrap: break-word;
  word-break: break-word;
}


.about-text h3 {
  margin-bottom: var(--spacing-md);
}

.about-text p {
  margin-bottom: var(--spacing-md);
}

/* Badge / tag for certifications, keywords */
.badge {
  display: inline-block;
  padding: var(--spacing-xs) var(--spacing-md);
  font-size: 0.8rem;
  font-weight: 500;
  border-radius: var(--border-radius-pill);
  margin: var(--spacing-xs);
}


/* ==========================================================
   6. Research Section
   ========================================================== */

.research-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--spacing-lg);
}

.research-card {
  background: var(--color-white);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-xl);
  text-align: center;
  box-shadow: 0 2px 12px var(--color-shadow);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
  border: 1px solid var(--color-border);
}

.research-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.12);
}


.research-card p {
  font-size: 0.9rem;
  line-height: 1.6;
}


/* ==========================================================
   7. Timeline (Experience)
   ========================================================== */

.timeline {
  position: relative;
  padding: var(--spacing-xl) 0;
}

/* Center line */
.timeline::before {
  content: '';
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  width: 2px;
  background: var(--color-border);
  transform: translateX(-50%);
}

.timeline-item {
  position: relative;
  width: 50%;
  padding: 0 var(--spacing-2xl);
  margin-bottom: var(--spacing-2xl);
}

/* Left items */
.timeline-item:nth-child(odd) {
  left: 0;
  text-align: right;
  padding-right: var(--spacing-3xl);
}

/* Right items */
.timeline-item:nth-child(even) {
  left: 50%;
  text-align: left;
  padding-left: var(--spacing-3xl);
}

/* Circle on the line */
.timeline-item::before {
  content: '';
  position: absolute;
  top: var(--spacing-md);
  width: 14px;
  height: 14px;
  background: var(--color-accent);
  border: 3px solid var(--color-white);
  border-radius: 50%;
  box-shadow: 0 0 0 3px var(--color-accent);
  z-index: 1;
}

.timeline-item:nth-child(odd)::before {
  right: -7px;
}

.timeline-item:nth-child(even)::before {
  left: -7px;
}


.timeline-date {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--color-accent);
  background: var(--color-light-green);
  padding: var(--spacing-xs) var(--spacing-md);
  border-radius: var(--border-radius-pill);
  margin-bottom: var(--spacing-sm);
}


/* ==========================================================
   8. Tabs (Projects)
   ========================================================== */


.tab-btn {
  padding: var(--spacing-md) var(--spacing-lg);
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--color-gray);
  border-bottom: 3px solid transparent;
  margin-bottom: -2px;
  white-space: nowrap;
  transition: color var(--transition-fast), border-color var(--transition-fast);
}

.tab-btn:hover {
  color: var(--color-primary);
}

.tab-btn.active {
  color: var(--color-primary);
  border-bottom-color: var(--color-accent);
}

/* Tab panels */
.tab-content {
  display: none;
  opacity: 0;
  transition: opacity var(--transition-base);
}

.tab-content.active {
  display: block;
  opacity: 1;
}


/* ==========================================================
   9. Accordion (Publications)
   ========================================================== */

.accordion {
  max-width: 900px;
  margin: 0 auto var(--spacing-md);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  overflow: hidden;
  background: var(--color-white);
}

.accordion-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: var(--spacing-lg) var(--spacing-lg);
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--color-primary);
  text-align: left;
  cursor: pointer;
  transition: background var(--transition-fast);
}

.accordion-header:hover {
  background: var(--color-light-gray);
}


.accordion-body {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease;
}

.accordion.open .accordion-body,
.accordion-body.open {
  max-height: 5000px;
}

.accordion-header.active .fa-chevron-down {
  transform: rotate(180deg);
}


/* ==========================================================
   10. Cards (Talks / Invited Lectures)
   ========================================================== */

.talks-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-lg);
}

.talk-card {
  background: var(--color-white);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-lg);
  box-shadow: 0 2px 12px var(--color-shadow);
  border: 1px solid var(--color-border);
  min-width: 0;
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.talk-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1);
}

.talk-date {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--color-white);
  background: var(--color-primary);
  padding: var(--spacing-xs) var(--spacing-md);
  border-radius: var(--border-radius-pill);
  margin-bottom: var(--spacing-md);
}


.talk-venue {
  font-size: 0.85rem;
  color: var(--color-gray);
}

.talk-venue i,
.talk-venue .icon {
  margin-right: var(--spacing-xs);
  color: var(--color-accent);
}

.talk-links {
  margin-top: var(--spacing-sm);
  padding-top: var(--spacing-sm);
  border-top: 1px solid var(--color-border);
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.talk-links a {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  font-size: 0.78rem;
  color: var(--color-primary);
  text-decoration: none;
  padding: 0.2rem 0.5rem;
  border-radius: var(--border-radius-sm);
  background: rgba(10, 61, 98, 0.06);
  transition: background 0.2s, color 0.2s;
}

.talk-links a:hover {
  background: var(--color-primary);
  color: var(--color-white);
}

.talk-links a i {
  font-size: 0.75rem;
}


/* ==========================================================
   11. Media Coverage
   ========================================================== */


.media-item {
  display: flex;
  align-items: flex-start;
  gap: var(--spacing-md);
  padding: var(--spacing-md);
  background: var(--color-white);
  border-radius: var(--border-radius);
  border: 1px solid var(--color-border);
  transition: box-shadow var(--transition-fast);
  min-width: 0;
  overflow: hidden;
}

.media-item:hover {
  box-shadow: 0 2px 12px var(--color-shadow);
}


.media-date {
  font-size: 0.8rem;
  color: var(--color-gray);
  margin-bottom: var(--spacing-xs);
}


/* ==========================================================
   12. Teaching Section
   ========================================================== */

.teaching-grid {
  display: grid;
  grid-template-columns: 2fr 3fr;
  gap: var(--spacing-3xl);
  align-items: start;
}


.course-list {
  list-style: none;
}

.course-list li {
  position: relative;
  padding: var(--spacing-md) 0 var(--spacing-md) var(--spacing-xl);
  border-bottom: 1px solid var(--color-border);
  font-size: 0.95rem;
  line-height: 1.6;
}

.course-list li:last-child {
  border-bottom: none;
}

/* Custom bullet */
.course-list li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 8px;
  height: 8px;
  background: var(--color-accent);
  border-radius: 50%;
}

.course-list li strong {
  display: block;
  color: var(--color-primary);
  margin-bottom: var(--spacing-xs);
}


/* ==========================================================
   13. Contact & Footer
   ========================================================== */

/* Contact section */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--spacing-xl);
  margin-top: var(--spacing-xl);
}

.contact-item {
  display: flex;
  align-items: flex-start;
  gap: var(--spacing-md);
}


/* Footer */
.footer {
  background: var(--color-primary);
  color: rgba(255, 255, 255, 0.8);
  padding: var(--spacing-2xl) 0;
}

.footer .container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-lg);
}


/* ==========================================================
   14. Utility Classes
   ========================================================== */

/* Fade-in animation (driven by Intersection Observer) */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity var(--transition-slow), transform var(--transition-slow);
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Section title with decorative underline */
.section-title {
  text-align: center;
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: var(--spacing-3xl);
  position: relative;
  padding-bottom: var(--spacing-md);
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 60px;
  height: 3px;
  background: var(--color-accent);
  border-radius: 2px;
}


/* ==========================================================
   15. Responsive Breakpoints
   ========================================================== */

/* --- Tablet: 769px - 1024px --- */
@media (max-width: 1024px) {
  h1 { font-size: 2rem; }
  h2 { font-size: 1.75rem; }

  .section-title {
    font-size: 1.75rem;
  }

  /* Research grid: 2 columns */
  .research-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  /* Talks grid: 2 columns */
  .talks-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* --- Mobile: max-width 768px --- */
@media (max-width: 768px) {
  :root {
    --container-pad: 16px;
  }

  .section {
    padding: 60px 0;
  }

  h1 { font-size: 1.75rem; }
  h2 { font-size: 1.5rem; }
  h3 { font-size: 1.25rem; }

  .section-title {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-2xl);
  }

  .lang-switcher {
    margin-left: 0;
  }

  /* --- Tabs mobile --- */
  .tab-btn {
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 0.85rem;
  }

  /* --- Footer --- */
  .footer .container {
    text-align: center;
  }
}

/* --- Small mobile: max-width 480px --- */
@media (max-width: 480px) {
  .talk-card {
    padding: var(--spacing-md);
  }

  .talk-topic {
    font-size: 0.9rem;
  }

  .media-item {
    padding: var(--spacing-sm);
  }

  .media-source {
    font-size: 0.7rem;
  }

  .accordion-header {
    padding: var(--spacing-md);
  }

  .publication-list li {
    font-size: 0.85rem;
  }
}

/* --- Desktop 1025px+ specific refinements --- */
@media (min-width: 1025px) {
  .about-grid {
    gap: var(--spacing-4xl);
  }

  .teaching-grid {
    gap: var(--spacing-4xl);
  }
}


/* ==========================================================
   16. Custom Scrollbar (WebKit)
   ========================================================== */

::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: var(--color-light-gray);
}

::-webkit-scrollbar-thumb {
  background: rgba(var(--color-primary-rgb), 0.3);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: rgba(var(--color-primary-rgb), 0.5);
}

/* Firefox scrollbar */
html {
  scrollbar-width: thin;
  scrollbar-color: rgba(var(--color-primary-rgb), 0.3) var(--color-light-gray);
}


/* ==========================================================
   17. Language-specific Overrides
   ========================================================== */

[lang="zh-TW"] body,
[lang="zh"] body {
  font-family: var(--font-chinese);
}

[lang="ja"] body {
  font-family: var(--font-japanese);
  line-height: 1.8;
}

[lang="ja"] h1,
[lang="ja"] h2,
[lang="ja"] h3,
[lang="ja"] h4 {
  line-height: 1.4;
}

[lang="ja"] p {
  line-height: 1.9;
}

/* ==========================================================
   18. Back to Top Button
   ========================================================== */

.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--color-primary);
  color: var(--color-white);
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
  transition: all var(--transition-base);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
  z-index: 999;
}

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

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

/* ==========================================================
   19. Project List & Publication List Styling
   ========================================================== */

.project-list {
  list-style: decimal;
  padding-left: 1.5rem;
}

.project-list li {
  padding: 0.75rem 0;
  border-bottom: 1px solid var(--color-border);
  line-height: 1.7;
  font-size: 0.95rem;
}

.project-list li:last-child {
  border-bottom: none;
}

.publication-list {
  list-style: decimal;
  padding-left: 1.5rem;
}

.publication-list li {
  padding: 0.6rem 0;
  line-height: 1.7;
  font-size: 0.9rem;
  border-bottom: 1px solid var(--color-border);
}

.publication-list li:last-child {
  border-bottom: none;
}

.pub-year {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--color-primary);
  margin: 1.5rem 0 0.75rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--color-accent);
  display: inline-block;
}

/* ==========================================================
   20. Hamburger Menu Animation
   ========================================================== */

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
  z-index: 1001;
}

.hamburger,
.hamburger::before,
.hamburger::after {
  display: block;
  width: 25px;
  height: 2px;
  background: var(--color-white);
  transition: all var(--transition-base);
}

.hamburger {
  position: relative;
}

.hamburger::before,
.hamburger::after {
  content: '';
  position: absolute;
}

.hamburger::before {
  top: -8px;
}

.hamburger::after {
  top: 8px;
}

.nav-open .hamburger {
  background: transparent;
}

.nav-open .hamburger::before {
  top: 0;
  transform: rotate(45deg);
}

.nav-open .hamburger::after {
  top: 0;
  transform: rotate(-45deg);
}

@media (max-width: 768px) {
  .nav-toggle {
    display: flex;
  }

  .nav-menu {
    position: fixed;
    top: 0;
    right: -100%;
    width: 280px;
    height: 100vh;
    background: var(--color-primary);
    flex-direction: column;
    padding: 5rem 2rem 2rem;
    transition: right var(--transition-base);
    z-index: 1000;
  }

  .nav-open .nav-menu {
    right: 0;
  }

  .nav-menu li {
    margin: 0.5rem 0;
  }

  .lang-switcher {
    margin-top: 1rem;
  }
}

/* ==========================================================
   21. Committee List
   ========================================================== */

.committee-list ul {
  list-style: none;
  padding: 0;
}

.committee-list li {
  padding: 0.6rem 0 0.6rem 1.5rem;
  position: relative;
  border-bottom: 1px solid var(--color-border);
  line-height: 1.7;
}

.committee-list li::before {
  content: '•';
  position: absolute;
  left: 0;
  color: var(--color-accent);
  font-weight: bold;
}

.committee-list li:last-child {
  border-bottom: none;
}

/* ==========================================================
   22. Missing HTML Class Aliases & Additional Styles
   ========================================================== */

/* Nav - HTML uses .nav-container, .nav-logo, .nav-link, .nav-menu */
.nav-container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-pad);
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.nav-logo {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--color-white);
  white-space: nowrap;
  flex-shrink: 0;
}

.nav-logo:hover {
  color: var(--color-light-blue);
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: var(--spacing-lg);
  list-style: none;
}

.nav-link {
  color: rgba(255, 255, 255, 0.85);
  font-size: 0.9rem;
  font-weight: 500;
  padding: var(--spacing-sm) 0;
  position: relative;
  transition: color var(--transition-fast);
  white-space: nowrap;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-accent);
  transition: width var(--transition-base);
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-white);
}

.nav-link:hover::after,
.nav-link.active::after {
  width: 100%;
}

/* Language buttons */
.lang-btn {
  color: rgba(255, 255, 255, 0.7);
  font-size: 0.85rem;
  font-weight: 500;
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--border-radius);
  transition: color var(--transition-fast), background var(--transition-fast);
}

.lang-btn:hover {
  color: var(--color-white);
  background: rgba(255, 255, 255, 0.1);
}

.lang-btn.active {
  color: var(--color-white);
  background: rgba(255, 255, 255, 0.2);
}

/* About subsection */
.about-subsection {
  margin-bottom: var(--spacing-xl);
}

.about-subsection h3 {
  font-size: 1.1rem;
  margin-bottom: var(--spacing-md);
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.about-subsection h3 i {
  color: var(--color-accent);
}

.about-subsection ul {
  list-style: none;
  padding: 0;
}

.about-subsection li {
  padding: 0.4rem 0 0.4rem 1.2rem;
  position: relative;
  line-height: 1.6;
  overflow-wrap: break-word;
  word-break: break-word;
}

.about-subsection li::before {
  content: '•';
  position: absolute;
  left: 0;
  color: var(--color-accent);
}

.about-intro {
  font-size: 1rem;
  line-height: 1.8;
  margin-bottom: var(--spacing-xl);
  text-align: left;
}

/* About section: first section, needs extra top padding for navbar */
.about-section {
  padding-top: calc(var(--nav-height) + 40px);
}

/* About hero name & title (replaces Hero section) */
.about-hero-name {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: var(--spacing-xs);
  text-align: center;
}

.about-hero-title {
  font-size: 1.1rem;
  color: var(--color-gray);
  text-align: center;
  margin-bottom: var(--spacing-md);
}

.about-hero-tagline {
  font-size: 1rem;
  font-weight: 500;
  color: var(--color-accent);
  text-align: center;
  margin-bottom: var(--spacing-2xl);
  letter-spacing: 0.05em;
}

/* About image container */
.about-image img {
  width: 100%;
  max-width: 350px;
  border-radius: var(--border-radius-lg);
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.12);
}

/* Specialty tags */
.specialty-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

.tag {
  display: inline-block;
  padding: var(--spacing-xs) var(--spacing-md);
  font-size: 0.85rem;
  font-weight: 500;
  border-radius: var(--border-radius-pill);
  background: var(--color-light-blue);
  color: var(--color-primary);
}

/* Cert badges container */
.cert-badges {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

.cert-badges .badge {
  background: var(--color-light-green);
  color: var(--color-accent);
}

/* Research icon */
.research-icon {
  width: 60px;
  height: 60px;
  margin: 0 auto var(--spacing-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.8rem;
  color: var(--color-accent);
  background: var(--color-light-green);
  border-radius: 50%;
}

/* Research card title (h3 not h4) */
.research-card h3 {
  font-size: 1.05rem;
  margin-bottom: var(--spacing-sm);
  color: var(--color-primary);
}

/* Timeline content and dot */
.timeline-content {
  background: var(--color-white);
  border-radius: var(--border-radius);
  padding: var(--spacing-lg);
  box-shadow: 0 2px 12px var(--color-shadow);
  border-left: 3px solid var(--color-accent);
  text-align: left;
}

.timeline-content p {
  margin-bottom: 0;
  color: var(--color-dark-text);
}

.timeline-dot {
  display: none; /* Hidden since we use ::before pseudo-element */
}

.timeline-dot.current {
  display: none;
}

/* Timeline group title */
.timeline-group-title {
  font-size: 1.2rem;
  color: var(--color-primary);
  margin: var(--spacing-2xl) 0 var(--spacing-lg);
  padding-bottom: var(--spacing-sm);
  border-bottom: 2px solid var(--color-accent);
  display: inline-block;
}

/* Tabs container */
.tabs {
  display: flex;
  gap: var(--spacing-sm);
  border-bottom: 2px solid var(--color-border);
  margin-bottom: var(--spacing-xl);
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}

.tabs::-webkit-scrollbar {
  display: none;
}

/* Talk topic (h3) */
.talk-topic {
  font-size: 1rem;
  margin-bottom: var(--spacing-sm);
  line-height: 1.4;
}

/* Media list and source */
.media-list {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-2xl);
}

.media-source {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--border-radius);
  background: var(--color-light-blue);
  color: var(--color-primary);
  flex-shrink: 0;
  margin-right: var(--spacing-sm);
}

.media-year-title {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--color-primary);
  border-bottom: 2px solid var(--color-accent);
  padding-bottom: var(--spacing-sm);
  margin-bottom: var(--spacing-lg);
  display: inline-block;
}

.media-item a {
  color: var(--color-dark-text);
  font-weight: 500;
}

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

/* Teaching block */
.teaching-block {
  margin-bottom: var(--spacing-xl);
}

.teaching-block h3 {
  font-size: 1.2rem;
  margin-bottom: var(--spacing-lg);
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.teaching-block h3 i {
  color: var(--color-accent);
}

/* Contact info and links */
.contact-info {
  display: grid;
  gap: var(--spacing-xl);
}

.contact-item i {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-light-blue);
  color: var(--color-primary);
  border-radius: 50%;
  font-size: 1.2rem;
  flex-shrink: 0;
}

.contact-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-md);
}

.contact-link-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-md) var(--spacing-xl);
  background: var(--color-light-blue);
  color: var(--color-primary);
  border-radius: var(--border-radius);
  font-weight: 500;
  transition: background var(--transition-fast), color var(--transition-fast);
}

.contact-link-btn:hover {
  background: var(--color-primary);
  color: var(--color-white);
}

/* QR Code block */
.qrcode-block {
  text-align: center;
  margin-top: var(--spacing-3xl);
  padding-top: var(--spacing-2xl);
  border-top: 1px solid var(--color-border);
}

.qrcode-block img {
  margin: 0 auto var(--spacing-md);
}

.qrcode-block p {
  font-size: 0.85rem;
  color: var(--color-gray);
}

/* ==========================================================
   23. Additional Responsive Overrides
   ========================================================== */

@media (max-width: 768px) {
  .about-grid {
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
    text-align: center;
  }

  .about-text {
    text-align: left;
  }

  .about-hero-name {
    font-size: 2rem;
  }

  .about-image img {
    margin: 0 auto var(--spacing-xl);
  }

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

  .timeline::before {
    left: 20px;
  }

  .timeline-item {
    width: 100%;
    padding-left: 50px !important;
    padding-right: 0 !important;
    text-align: left !important;
  }

  .timeline-item:nth-child(even) {
    left: 0;
  }

  .timeline-item::before {
    left: 13px !important;
    right: auto !important;
  }

  .talks-grid {
    grid-template-columns: 1fr;
  }

  .media-list {
    grid-template-columns: 1fr;
  }

  .media-item {
    flex-direction: column;
    gap: var(--spacing-xs);
  }

  .media-source {
    align-self: flex-start;
    white-space: normal;
  }

  .talk-links {
    flex-direction: column;
    align-items: flex-start;
  }

  .talk-links a {
    max-width: 100%;
    overflow: hidden;
    text-overflow: ellipsis;
  }

  .teaching-grid {
    grid-template-columns: 1fr;
  }

  .contact-grid {
    grid-template-columns: 1fr;
  }

  .contact-links {
    flex-direction: column;
  }
}

@media (max-width: 480px) {
  .research-grid {
    grid-template-columns: 1fr;
  }

  .tabs {
    flex-wrap: nowrap;
    overflow-x: auto;
  }

  .tab-btn {
    font-size: 0.85rem;
    padding: var(--spacing-sm) var(--spacing-md);
  }
}