/* ================================================================
   ThinBaker — Personal Brand Website
   Design System & Styles
   Inspired by: Ali Abdaal (clean educator aesthetic),
                Naval Ravikant (minimal, high-signal),
                Tobias van Schneider (bold typographic personality)
   ================================================================ */

/* ----------------------------------------------------------------
   1. CSS Custom Properties (Design Tokens)
   ---------------------------------------------------------------- */
:root {
  /* Dark mode defaults */
  --color-bg:           #000000;
  --color-bg-elevated:  #111111;
  --color-bg-card:      #1a1a1a;
  --color-bg-card-hover:#222222;
  --color-border:       rgba(255, 255, 255, 0.12);
  --color-border-hover: rgba(255, 255, 255, 0.22);

  /* Accent: flat purple */
  --color-accent:       #7c3aed;
  --color-accent-light: #9b59f7;
  --color-accent-pale:  rgba(124, 58, 237, 0.12);

  /* Text */
  --color-text-primary:   #ffffff;
  --color-text-secondary: #888888;
  --color-text-muted:     #555555;

  /* Pillars */
  --color-professional: #3b82f6;
  --color-researcher:   #10b981;
  --color-teacher:      #f59e0b;

  /* Theme-dependent values */
  --color-nav-bg:          rgba(0, 0, 0, 0.92);
  --color-mobile-menu-bg:  rgba(0, 0, 0, 0.97);
  --color-ghost:           rgba(255, 255, 255, 0.04);
  --color-link-hover-bg:   rgba(255, 255, 255, 0.06);

  /* Typography */
  --font-display: 'Space Grotesk', system-ui, sans-serif;
  --font-body:    'Inter', system-ui, sans-serif;

  /* Fluid type scale — clamp(min, preferred, max) */
  --text-xs:   clamp(0.75rem,  0.7rem  + 0.25vw, 0.875rem);
  --text-sm:   clamp(0.875rem, 0.85rem + 0.3vw,  1rem);
  --text-base: clamp(1rem,     0.95rem + 0.35vw, 1.125rem);
  --text-lg:   clamp(1.125rem, 1.05rem + 0.5vw,  1.375rem);
  --text-xl:   clamp(1.375rem, 1.2rem  + 0.9vw,  1.875rem);
  --text-2xl:  clamp(1.75rem,  1.4rem  + 1.8vw,  2.75rem);
  --text-3xl:  clamp(2.25rem,  1.6rem  + 3.2vw,  4rem);
  --text-hero: clamp(2.25rem,  1.6rem  + 3.2vw,  4rem);

  /* Spacing */
  --space-1:   0.25rem;
  --space-2:   0.5rem;
  --space-3:   0.75rem;
  --space-4:   1rem;
  --space-6:   1.5rem;
  --space-8:   2rem;
  --space-12:  3rem;
  --space-16:  4rem;
  --space-24:  6rem;
  --space-32:  6rem;

  /* Layout */
  --max-width:    1200px;
  --nav-height:   72px;

  /* Radius */
  --radius-sm:   6px;
  --radius-md:   12px;
  --radius-lg:   20px;
  --radius-xl:   32px;
  --radius-full: 9999px;

  /* Transitions */
  --transition-fast:   150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base:   250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow:   400ms cubic-bezier(0.4, 0, 0.2, 1);

  /* Shadows — flat, no glow */
  --shadow-card:       0 1px 3px rgba(0,0,0,0.4);
  --shadow-card-hover: 0 4px 12px rgba(0,0,0,0.5);
}

@media (prefers-color-scheme: light) {
  :root {
    --color-bg:           #ffffff;
    --color-bg-elevated:  #f5f5f5;
    --color-bg-card:      #eeeeee;
    --color-bg-card-hover:#e5e5e5;
    --color-border:       rgba(0, 0, 0, 0.1);
    --color-border-hover: rgba(0, 0, 0, 0.2);
    --color-accent:       #5b21b6;
    --color-accent-light: #6d28d9;
    --color-accent-pale:  rgba(91, 33, 182, 0.1);
    --color-text-primary:   #000000;
    --color-text-secondary: #555555;
    --color-text-muted:     #999999;
    --color-nav-bg:          rgba(255, 255, 255, 0.92);
    --color-mobile-menu-bg:  rgba(255, 255, 255, 0.97);
    --color-ghost:           rgba(0, 0, 0, 0.04);
    --color-link-hover-bg:   rgba(0, 0, 0, 0.05);
    --shadow-card:       0 1px 3px rgba(0,0,0,0.1);
    --shadow-card-hover: 0 4px 12px rgba(0,0,0,0.15);
  }
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--nav-height);
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-body);
  font-size: var(--text-base);
  line-height: 1.7;
  color: var(--color-text-primary);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

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

a {
  color: inherit;
  text-decoration: none;
}

ul, ol {
  list-style: none;
}

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

/* ----------------------------------------------------------------
   3. Typography Utilities
   ---------------------------------------------------------------- */
.section-eyebrow {
  font-family: var(--font-display);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--color-accent-light);
  margin-bottom: var(--space-4);
}

.section-heading {
  font-family: var(--font-display);
  font-size: var(--text-2xl);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.02em;
  color: var(--color-text-primary);
  margin-bottom: var(--space-6);
}

.section-subheading {
  font-size: var(--text-lg);
  color: var(--color-text-secondary);
  line-height: 1.65;
}

.accent {
  color: var(--color-accent-light);
}

.accent--teacher {
  color: #f59e0b;
}

/* ----------------------------------------------------------------
   4. Button System
   ---------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: 0.75rem 1.75rem;
  font-family: var(--font-display);
  font-size: var(--text-sm);
  font-weight: 600;
  border-radius: var(--radius-full);
  transition: all var(--transition-base);
  text-decoration: none;
  white-space: nowrap;
}

.btn--primary {
  background: var(--color-accent);
  color: #fff;
}

.btn--primary:hover,
.btn--primary:focus-visible {
  background: #6d28d9;
  transform: translateY(-1px);
}

.btn--ghost {
  background: transparent;
  color: var(--color-text-primary);
  border: 1px solid var(--color-border-hover);
}

.btn--ghost:hover,
.btn--ghost:focus-visible {
  background: var(--color-accent-pale);
  border-color: var(--color-accent);
  color: var(--color-accent-light);
}

.btn--teacher {
  border-color: #f59e0b;
  color: #f59e0b;
}

.btn--teacher:hover,
.btn--teacher:focus-visible {
  background: rgba(245, 158, 11, 0.1);
  border-color: #f59e0b;
  color: #f59e0b;
}

.btn--outline {
  background: transparent;
  color: var(--color-text-primary);
  border: 1px solid var(--color-border-hover);
  padding: 0.6rem 1.4rem;
}

.btn--outline:hover,
.btn--outline:focus-visible {
  background: var(--color-accent-pale);
  border-color: var(--color-accent);
  color: var(--color-accent-light);
}

/* Focus ring for accessibility */
:focus-visible {
  outline: 2px solid var(--color-accent-light);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

/* ----------------------------------------------------------------
   5. Navigation
   ---------------------------------------------------------------- */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: var(--nav-height);
  transition: background var(--transition-base), backdrop-filter var(--transition-base),
              border-color var(--transition-base);
  border-bottom: 1px solid transparent;
}

.nav.is-scrolled {
  background: var(--color-nav-bg);
  border-bottom-color: var(--color-border);
}

.nav__container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-6);
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-8);
}

.nav__left {
  display: flex;
  align-items: center;
  gap: var(--space-6);
}

.nav__logo {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  text-decoration: none;
  flex-shrink: 0;
}

.nav__logo-name {
  font-family: var(--font-display);
  font-size: var(--text-sm);
  font-weight: 700;
  color: var(--color-text-primary);
  letter-spacing: -0.01em;
  transition: color var(--transition-fast);
}

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

.nav__logo-dot {
  width: 6px;
  height: 6px;
  background: var(--color-accent);
  border-radius: var(--radius-full);
  flex-shrink: 0;
}

.nav__menu {
  display: flex;
  align-items: center;
  gap: var(--space-1);
}

.nav__link {
  font-family: var(--font-display);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-full);
  transition: color var(--transition-fast), background var(--transition-fast);
  text-decoration: none;
}

.nav__link:hover,
.nav__link:focus-visible {
  color: var(--color-text-primary);
  background: var(--color-link-hover-bg);
}

.nav__link--cta {
  background: var(--color-accent);
  color: #fff !important;
  padding: 0.5rem 1.25rem;
  font-weight: 600;
}

.nav__link--cta:hover,
.nav__link--cta:focus-visible {
  background: #6d28d9;
  color: #fff !important;
}

.nav__toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: var(--space-2);
  border-radius: var(--radius-sm);
}

.nav__toggle-bar {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-text-primary);
  border-radius: var(--radius-full);
  transition: transform var(--transition-base), opacity var(--transition-base);
}

/* ----------------------------------------------------------------
   6. Hero Section
   ---------------------------------------------------------------- */
.hero {
  position: relative;
  min-height: 100svh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding-top: var(--nav-height);
  overflow: hidden;
}

/* Dot-grid background */
.hero__bg-grid {
  display: none;
}

/* Ambient glow */
.hero__glow {
  display: none;
}

.hero__container {
  position: relative;
  z-index: 1;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-16) var(--space-6);
  display: grid;
  grid-template-columns: 1fr 1fr;
  align-items: center;
  gap: var(--space-16);
}

.hero__content {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
}

.hero__eyebrow {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-display);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-accent-light);
  margin-bottom: var(--space-6);
}

.hero__eyebrow-dot {
  display: inline-block;
  width: 7px;
  height: 7px;
  background: var(--color-accent);
  border-radius: var(--radius-full);
  animation: pulse-dot 2.5s ease-in-out infinite;
  flex-shrink: 0;
}

@keyframes pulse-dot {
  0%, 100% { transform: scale(1); opacity: 1; }
  50%       { transform: scale(1.4); opacity: 0.7; }
}

.hero__headline {
  font-family: var(--font-display);
  font-size: var(--text-hero);
  font-weight: 700;
  line-height: 1.05;
  letter-spacing: -0.03em;
  color: var(--color-text-primary);
  margin-bottom: var(--space-6);
}

.hero__headline-accent {
  color: var(--color-accent-light);
}

.hero__subheadline {
  font-size: var(--text-lg);
  color: var(--color-text-secondary);
  line-height: 1.7;
  max-width: 520px;
  margin-bottom: var(--space-8);
}

.hero__subheadline strong {
  color: var(--color-text-primary);
  font-weight: 600;
}

.hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  margin-bottom: var(--space-8);
}

.hero__social {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
  align-items: center;
}

.hero__social-link {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  font-weight: 500;
  transition: color var(--transition-fast);
  text-decoration: none;
}

.hero__social-link:hover {
  color: var(--color-accent-light);
}

/* Hero visual / photo */
.hero__visual {
  display: flex;
  justify-content: center;
  align-items: center;
}

.hero__photo-wrapper {
  position: relative;
  width: 100%;
  max-width: 420px;
}

.hero__photo {
  width: 100%;
  aspect-ratio: 5 / 6;
  object-fit: cover;
  object-position: center top;
  border-radius: var(--radius-xl);
  filter: grayscale(15%);
  transition: filter var(--transition-slow);
  box-shadow: var(--shadow-card), 0 0 0 1px var(--color-border);
}

.hero__photo-wrapper:hover .hero__photo {
  filter: grayscale(0%);
}

/* Decorative border removed */

.hero__photo-badge {
  position: absolute;
  bottom: var(--space-6);
  left: calc(-1 * var(--space-6));
  display: flex;
  align-items: center;
  gap: var(--space-2);
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  padding: var(--space-2) var(--space-4);
  font-family: var(--font-display);
  font-size: var(--text-xs);
  font-weight: 600;
  color: var(--color-text-primary);
  box-shadow: var(--shadow-card);
  white-space: nowrap;
}

.hero__photo-badge-icon {
  font-size: 1rem;
}

/* Scrolling ticker */
.hero__ticker {
  position: relative;
  z-index: 1;
  width: 100%;
  overflow: hidden;
  border-top: 1px solid var(--color-border);
  padding: var(--space-4) 0;
}

.hero__ticker-track {
  display: flex;
  gap: var(--space-8);
  width: max-content;
  animation: ticker-scroll 28s linear infinite;
  font-family: var(--font-display);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text-muted);
}

.hero__ticker-track span:not([aria-hidden]) {
  white-space: nowrap;
}

@keyframes ticker-scroll {
  0%   { transform: translateX(0); }
  100% { transform: translateX(-50%); }
}

/* ----------------------------------------------------------------
   7. About Section
   ---------------------------------------------------------------- */
.about {
  padding: var(--space-32) 0;
  background: var(--color-bg-elevated);
}

.about__container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-6);
}

.about__header {
  margin-bottom: var(--space-16);
}

.about__body {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-16);
  align-items: start;
}

.about__text p {
  color: var(--color-text-secondary);
  margin-bottom: var(--space-6);
  font-size: var(--text-base);
  line-height: 1.8;
}

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

.about__text strong {
  color: var(--color-text-primary);
  font-weight: 600;
}

.about__pillars {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.pillar-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  transition: transform var(--transition-base), box-shadow var(--transition-base),
              border-color var(--transition-base);
  position: relative;
  overflow: hidden;
}

.pillar-card::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
  border-radius: var(--radius-sm) 0 0 var(--radius-sm);
}

.pillar-card--professional::before { background: var(--color-professional); }
.pillar-card--researcher::before   { background: var(--color-researcher); }
.pillar-card--teacher::before      { background: var(--color-teacher); }

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

.pillar-card__icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  margin-bottom: var(--space-4);
}

.pillar-card--professional .pillar-card__icon { background: rgba(59,130,246,0.12); color: var(--color-professional); }
.pillar-card--teacher   .pillar-card__icon { background: rgba(16,185,129,0.12); color: var(--color-researcher); }
.pillar-card--teacher      .pillar-card__icon { background: rgba(245,158,11,0.12); color: var(--color-teacher); }

.pillar-card__title {
  font-family: var(--font-display);
  font-size: var(--text-base);
  font-weight: 700;
  color: var(--color-text-primary);
  margin-bottom: var(--space-2);
}

.pillar-card__desc {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  line-height: 1.65;
}

/* ----------------------------------------------------------------
   8. Services / Consulting Section
   ---------------------------------------------------------------- */
.services {
  padding: var(--space-32) 0;
  background: var(--color-bg);
  position: relative;
}

.services__container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-6);
}

.services__header {
  margin-bottom: var(--space-16);
}

.services__grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-6);
  margin-bottom: var(--space-16);
}

.service-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-8);
  transition: transform var(--transition-base), box-shadow var(--transition-base),
              border-color var(--transition-base);
  position: relative;
}

.service-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-card-hover);
  border-color: var(--color-accent);
}

.service-card__number {
  font-family: var(--font-display);
  font-size: clamp(3rem, 5vw, 5rem);
  font-weight: 800;
  color: var(--color-ghost);
  line-height: 1;
  position: absolute;
  top: var(--space-4);
  right: var(--space-6);
  letter-spacing: -0.04em;
  user-select: none;
  pointer-events: none;
}

.service-card__icon {
  color: var(--color-accent-light);
  margin-bottom: var(--space-4);
}

.service-card__title {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 700;
  color: var(--color-text-primary);
  margin-bottom: var(--space-3);
  letter-spacing: -0.01em;
}

.service-card__desc {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  line-height: 1.7;
  margin-bottom: var(--space-6);
}

.service-card__tags {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: var(--space-2);
}

.service-card__tags li {
  font-family: var(--font-display);
  font-size: var(--text-xs);
  font-weight: 600;
  color: var(--color-accent-light);
  background: var(--color-accent-pale);
  border: 1px solid rgba(124, 58, 237, 0.2);
  border-radius: var(--radius-full);
  padding: 0.2rem 0.7rem;
  letter-spacing: 0.02em;
}

.services__cta {
  text-align: center;
}

.services__cta p {
  color: var(--color-text-secondary);
  margin-bottom: var(--space-4);
  font-size: var(--text-lg);
}

/* ----------------------------------------------------------------
   9. Research Section
   ---------------------------------------------------------------- */
.research {
  padding: var(--space-32) 0;
  background: var(--color-bg);
}

.research__container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-6);
}

.research__header {
  margin-bottom: var(--space-16);
}

.research__areas {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-6);
  margin-bottom: var(--space-12);
}

.research-area {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-8);
  display: flex;
  flex-direction: column;
  transition: transform var(--transition-base), box-shadow var(--transition-base),
              border-color var(--transition-base);
}

.research-area:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-card-hover);
  border-color: rgba(16, 185, 129, 0.25);
}

.research-area__tag {
  font-family: var(--font-display);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-researcher);
  margin-bottom: var(--space-4);
}

.research-area__title {
  font-family: var(--font-display);
  font-size: var(--text-base);
  font-weight: 700;
  color: var(--color-text-primary);
  margin-bottom: var(--space-3);
  line-height: 1.3;
}

.research-area__desc {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  line-height: 1.7;
  flex-grow: 1;
  margin-bottom: var(--space-6);
}

.research-area__link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  font-family: var(--font-display);
  font-size: var(--text-xs);
  font-weight: 600;
  color: var(--color-researcher);
  text-decoration: none;
  transition: gap var(--transition-fast), color var(--transition-fast);
  margin-top: auto;
}

.research-area__link:hover {
  gap: var(--space-2);
  color: #34d399;
}

.research__github-cta {
  width: 100%;
}

.research__github-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-8);
  display: flex;
  align-items: center;
  gap: var(--space-6);
  flex-wrap: wrap;
}

.research__github-icon {
  color: var(--color-text-secondary);
  flex-shrink: 0;
}

.research__github-text {
  flex: 1;
  min-width: 200px;
}

.research__github-text h3 {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 700;
  color: var(--color-text-primary);
  margin-bottom: var(--space-1);
}

.research__github-text p {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
}

/* ----------------------------------------------------------------
   10. Teaching Section
   ---------------------------------------------------------------- */
.teaching {
  padding: var(--space-32) 0;
  background: var(--color-bg-elevated);
}

.teaching__container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-6);
}

.teaching__carousel {
  overflow: hidden;
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
  padding: var(--space-3) 0;
  margin-top: var(--space-8);
  margin-bottom: var(--space-16);
}

.teaching__carousel-track {
  display: flex;
  gap: var(--space-8);
  width: max-content;
  animation: ticker-scroll 20s linear infinite;
  font-family: var(--font-display);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  white-space: nowrap;
}

.teaching__carousel-dot {
  opacity: 0.4;
}

.teaching__header {
  margin-bottom: var(--space-16);
}

.teaching__grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-6);
  margin-bottom: var(--space-16);
}

.teaching-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-8);
  display: flex;
  flex-direction: column;
  transition: transform var(--transition-base), box-shadow var(--transition-base),
              border-color var(--transition-base);
}

.teaching-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-card-hover);
  border-color: rgba(245, 158, 11, 0.25);
}

.teaching-card__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-4);
}

.teaching-card__badge {
  font-family: var(--font-display);
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-teacher);
  background: rgba(245, 158, 11, 0.1);
  border: 1px solid rgba(245, 158, 11, 0.2);
  border-radius: var(--radius-full);
  padding: 0.2rem 0.7rem;
}

.teaching-card__stars {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  font-size: var(--text-xs);
  color: var(--color-teacher);
  font-weight: 600;
}

.teaching-card__title {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 700;
  color: var(--color-text-primary);
  margin-bottom: var(--space-3);
  letter-spacing: -0.01em;
}

.teaching-card__desc {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  line-height: 1.7;
  flex-grow: 1;
  margin-bottom: var(--space-6);
}

.teaching-card__link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  font-family: var(--font-display);
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-teacher);
  text-decoration: none;
  margin-top: auto;
  transition: gap var(--transition-fast), color var(--transition-fast);
}

.teaching-card__link:hover {
  gap: var(--space-2);
  color: #fbbf24;
}

.teaching__cta {
  text-align: center;
}

.teaching__cta p {
  color: var(--color-text-secondary);
  margin-bottom: var(--space-4);
  font-size: var(--text-lg);
}

/* ----------------------------------------------------------------
   11. Contact Section
   ---------------------------------------------------------------- */
.contact {
  padding: var(--space-32) 0;
  background: var(--color-bg);
  position: relative;
  overflow: hidden;
}

/* No ambient glow */

.contact__container {
  position: relative;
  z-index: 1;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-6);
}

.contact__header {
  margin-bottom: var(--space-16);
}

.contact__body {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-8);
  align-items: start;
}

.contact__channels {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.contact-channel {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  text-decoration: none;
  transition: transform var(--transition-base), box-shadow var(--transition-base),
              border-color var(--transition-base);
}

.contact-channel:hover {
  transform: translateX(4px);
  box-shadow: var(--shadow-card-hover);
  border-color: var(--color-border-hover);
}

.contact-channel__icon {
  color: var(--color-accent-light);
  flex-shrink: 0;
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-accent-pale);
  border-radius: var(--radius-md);
}

.contact-channel__text {
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 2px;
}


.contact-channel__text strong {
  font-family: var(--font-display);
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-text-primary);
}

.contact-channel__text span {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.contact-channel__arrow {
  color: var(--color-text-muted);
  flex-shrink: 0;
  transition: transform var(--transition-fast), color var(--transition-fast);
}

.contact-channel:hover .contact-channel__arrow {
  transform: translateX(3px);
  color: var(--color-accent-light);
}

/* Contact card */
.contact__card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-8);
  height: 100%;
}

.contact__card-eyebrow {
  font-family: var(--font-display);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin-bottom: var(--space-1);
}

.contact__card-location {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 700;
  color: var(--color-text-primary);
  margin-bottom: var(--space-4);
}

.contact__card-availability {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-sm);
  color: #34d399;
  font-weight: 500;
  margin-bottom: var(--space-6);
}

.contact__availability-dot {
  width: 8px;
  height: 8px;
  background: #34d399;
  border-radius: var(--radius-full);
  animation: pulse-dot 2.5s ease-in-out infinite;
  flex-shrink: 0;
}

.contact__card-divider {
  height: 1px;
  background: var(--color-border);
  margin-bottom: var(--space-6);
}

.contact__card-quote {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  line-height: 1.75;
  font-style: italic;
  margin-bottom: var(--space-3);
}

.contact__card-attribution {
  font-family: var(--font-display);
  font-size: var(--text-xs);
  font-weight: 600;
  color: var(--color-text-muted);
}

/* ----------------------------------------------------------------
   12. Footer
   ---------------------------------------------------------------- */
.footer {
  background: var(--color-bg-elevated);
  border-top: 1px solid var(--color-border);
  padding: var(--space-12) 0;
}

.footer__container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-6);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-8);
}

.footer__name {
  font-family: var(--font-display);
  font-size: var(--text-base);
  font-weight: 700;
  color: var(--color-text-primary);
  margin-bottom: var(--space-1);
}

.footer__tagline {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
}

.footer__right {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: var(--space-4);
}

.footer__right nav {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
  justify-content: flex-end;
}

.footer__link {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
  transition: color var(--transition-fast), background var(--transition-fast);
  text-decoration: none;
}

.footer__link:hover {
  color: var(--color-text-primary);
  background: var(--color-link-hover-bg);
}

.footer__copy {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
}

/* ----------------------------------------------------------------
   13. Back to Top Button
   ---------------------------------------------------------------- */
.back-to-top {
  position: fixed;
  bottom: var(--space-8);
  left: var(--space-8);
  z-index: 50;
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  color: var(--color-text-secondary);
  box-shadow: var(--shadow-card);
  opacity: 0;
  transform: translateY(8px);
  pointer-events: none;
  transition: opacity var(--transition-base), transform var(--transition-base),
              background var(--transition-fast), color var(--transition-fast);
}

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

.back-to-top:hover {
  background: var(--color-accent);
  color: #fff;
  border-color: var(--color-accent);
}

/* ----------------------------------------------------------------
   14. AOS Animation Overrides
   ---------------------------------------------------------------- */
[data-aos] {
  transition-timing-function: cubic-bezier(0.4, 0, 0.2, 1) !important;
}

/* ----------------------------------------------------------------
   15. Responsive — Tablet (768px)
   ---------------------------------------------------------------- */
@media (max-width: 1024px) {
  .hero__container {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .hero__content {
    align-items: center;
    order: 2;
  }

  .hero__visual {
    order: 1;
  }

  .hero__photo-wrapper {
    max-width: 280px;
  }

  .hero__photo-badge {
    left: 50%;
    transform: translateX(-50%);
    bottom: calc(-1 * var(--space-6));
  }

  .hero__subheadline {
    text-align: center;
  }

  .hero__actions {
    justify-content: center;
  }

  .hero__social {
    justify-content: center;
  }

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

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

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

  .footer__right {
    align-items: flex-start;
  }
}

@media (max-width: 768px) {
  /* Mobile nav */
  .nav__toggle {
    display: flex;
  }

  .nav__menu {
    display: none;
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    background: var(--color-mobile-menu-bg);
    border-bottom: 1px solid var(--color-border);
    padding: var(--space-4) var(--space-6) var(--space-6);
    gap: var(--space-1);
    z-index: 99;
  }

  .nav__menu.is-open {
    display: flex;
  }

  .nav__link {
    padding: var(--space-3) var(--space-4);
    border-radius: var(--radius-md);
    text-align: center;
  }

  .nav__link--cta {
    margin-top: var(--space-2);
    text-align: center;
  }

  /* Hamburger → X animation */
  .nav__toggle.is-active .nav__toggle-bar:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
  }
  .nav__toggle.is-active .nav__toggle-bar:nth-child(2) {
    opacity: 0;
    transform: scaleX(0);
  }
  .nav__toggle.is-active .nav__toggle-bar:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
  }

  /* Grid layouts → single column */
  .services__grid,
  .teaching__grid {
    grid-template-columns: 1fr;
  }

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

  .research__github-card {
    flex-direction: column;
    align-items: flex-start;
  }

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

  .footer__right {
    align-items: flex-start;
  }

  .footer__right nav {
    justify-content: flex-start;
  }

  .back-to-top {
    bottom: var(--space-6);
    left: var(--space-6);
  }

  /* About: github link outside container needs padding */
  .about__github {
    padding: 0 var(--space-6);
  }

  /* About: git-ref long text truncation */
  .git-ref {
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    max-width: 100%;
  }

  /* Contact: reduce padding on channel cards and info card */
  .contact-channel {
    padding: var(--space-4);
  }

  .contact__card {
    padding: var(--space-5);
  }
}

/* ----------------------------------------------------------------
   16. Reduced Motion
   ---------------------------------------------------------------- */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  .hero__ticker-track {
    animation: none;
  }
}

/* ----------------------------------------------------------------
   17. Theme Toggle — manual dark/light override
   ---------------------------------------------------------------- */

/* Force dark mode regardless of system preference */
html[data-theme="dark"] {
  --color-bg:           #000000;
  --color-bg-elevated:  #111111;
  --color-bg-card:      #1a1a1a;
  --color-bg-card-hover:#222222;
  --color-border:       rgba(255, 255, 255, 0.12);
  --color-border-hover: rgba(255, 255, 255, 0.22);
  --color-accent:       #7c3aed;
  --color-accent-light: #9b59f7;
  --color-accent-pale:  rgba(124, 58, 237, 0.12);
  --color-text-primary:   #ffffff;
  --color-text-secondary: #888888;
  --color-text-muted:     #555555;
  --color-nav-bg:          rgba(0, 0, 0, 0.92);
  --color-mobile-menu-bg:  rgba(0, 0, 0, 0.97);
  --color-ghost:           rgba(255, 255, 255, 0.04);
  --color-link-hover-bg:   rgba(255, 255, 255, 0.06);
  --shadow-card:       0 1px 3px rgba(0,0,0,0.4);
  --shadow-card-hover: 0 4px 12px rgba(0,0,0,0.5);
}

/* Force light mode regardless of system preference */
html[data-theme="light"] {
  --color-bg:           #ffffff;
  --color-bg-elevated:  #f5f5f5;
  --color-bg-card:      #eeeeee;
  --color-bg-card-hover:#e5e5e5;
  --color-border:       rgba(0, 0, 0, 0.1);
  --color-border-hover: rgba(0, 0, 0, 0.2);
  --color-accent:       #5b21b6;
  --color-accent-light: #6d28d9;
  --color-accent-pale:  rgba(91, 33, 182, 0.1);
  --color-text-primary:   #000000;
  --color-text-secondary: #555555;
  --color-text-muted:     #999999;
  --color-nav-bg:          rgba(255, 255, 255, 0.92);
  --color-mobile-menu-bg:  rgba(255, 255, 255, 0.97);
  --color-ghost:           rgba(0, 0, 0, 0.04);
  --color-link-hover-bg:   rgba(0, 0, 0, 0.05);
  --shadow-card:       0 1px 3px rgba(0,0,0,0.1);
  --shadow-card-hover: 0 4px 12px rgba(0,0,0,0.15);
}

/* Theme toggle button */
.nav__actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.nav__theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-full);
  border: 1px solid var(--color-border);
  background: transparent;
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: color var(--transition-fast), border-color var(--transition-fast),
              background var(--transition-fast);
  flex-shrink: 0;
}

.nav__theme-toggle:hover {
  color: var(--color-text-primary);
  border-color: var(--color-border-hover);
  background: var(--color-link-hover-bg);
}

/* Show sun icon in dark mode, moon in light mode */
.theme-icon--sun  { display: none; }
.theme-icon--moon { display: block; }

html[data-theme="light"] .theme-icon--sun  { display: block; }
html[data-theme="light"] .theme-icon--moon { display: none; }

html[data-theme="dark"] .theme-icon--sun  { display: none; }
html[data-theme="dark"] .theme-icon--moon { display: block; }

/* When system is light but no override: show sun to switch to dark */
@media (prefers-color-scheme: light) {
  html:not([data-theme]) .theme-icon--sun  { display: block; }
  html:not([data-theme]) .theme-icon--moon { display: none; }
}

/* Language toggle pill */
.lang-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 28px;
  padding: 0 var(--space-3);
  border-radius: var(--radius-full);
  border: 1px solid var(--color-border);
  background: transparent;
  color: var(--color-text-secondary);
  font-family: var(--font-display);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.05em;
  cursor: pointer;
  transition: color var(--transition-fast), border-color var(--transition-fast),
              background var(--transition-fast);
  flex-shrink: 0;
}

.lang-toggle:hover,
.lang-toggle:focus-visible {
  color: var(--color-accent-light);
  border-color: var(--color-accent);
  background: var(--color-accent-pale);
}

.lang-toggle__label {
  pointer-events: none;
}

/* About GitHub link */
.about__github {
  max-width: 580px;
  margin: 1.5rem auto 0;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.about__github p {
  color: var(--color-text-secondary);
  font-size: var(--text-sm);
  margin: 0;
}

.about__github-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-accent);
  text-decoration: none;
}

.about__github-link:hover {
  color: var(--color-accent-light);
}

/* ----------------------------------------------------------------
   18. Git Graph (About Section)
   ---------------------------------------------------------------- */
.git-graph {
  --git-main:   #f59e0b;
  --git-branch: #fcd34d;
  margin: 1.5rem auto;
  padding: 0 1rem;
}

.git-row {
  display: flex;
  align-items: stretch;
  gap: 2.5rem;
  margin-bottom: 0.5rem;
  margin-left: 1rem;
}

/* SVG lane column */
.git-lanes {
  position: relative;
  width: 60px;
  flex-shrink: 0;
}

.git-lanes svg {
  display: block;
  width: 60px;
  height: 100%;
}

/* Commit dots — absolutely centred vertically */
.git-dot {
  position: absolute;
  left: 4px;
  top: 50%;
  transform: translateY(-50%);
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--git-main);
  border: 2px solid var(--color-bg);
  z-index: 1;
}

.git-dot--branch {
  left: auto;
  right: 4px;
  background: var(--git-branch);
}

/* Root commit: hollow ring */
.git-dot--root {
  background: var(--color-bg);
  border-color: var(--git-main);
  border-width: 2px;
}

/* Commit card */
.git-card {
  flex: 1;
  min-width: 0;
  overflow: hidden;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 0.6rem 0.875rem;
}

.git-ref {
  display: block;
  font-family: 'Courier New', monospace;
  font-size: 0.7rem;
  color: var(--color-accent);
  margin-bottom: 0.2rem;
  opacity: 0.8;
}

.git-ref--branch {
  color: var(--color-accent-light);
}

.git-title {
  font-family: var(--font-display);
  font-size: var(--text-base);
  font-weight: 700;
  color: var(--color-text-primary);
  margin: 0 0 0.2rem;
}

.git-desc {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  line-height: 1.5;
  margin: 0;
}

.git-artifact {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-top: 0.65rem;
  padding: 0.35rem 0.6rem;
  background: color-mix(in srgb, var(--color-accent) 6%, transparent);
  border: 1px solid var(--color-border);
  border-left: 3px solid var(--git-main);
  border-radius: 4px;
  text-decoration: none;
  transition: border-left-color 0.2s ease, background 0.2s ease;
}
.git-artifact:hover {
  background: color-mix(in srgb, var(--color-accent) 12%, transparent);
  border-left-color: var(--color-accent);
}
.git-artifact__label {
  font-family: 'Courier New', monospace;
  font-size: 0.65rem;
  color: var(--color-accent);
  background: color-mix(in srgb, var(--color-accent) 12%, transparent);
  padding: 0.1rem 0.3rem;
  border-radius: 3px;
  flex-shrink: 0;
}
.git-artifact__name {
  font-family: 'Courier New', monospace;
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--color-text-primary);
  flex-shrink: 0;
}
.git-artifact__desc {
  font-size: 0.7rem;
  color: var(--color-text-secondary);
  flex: 1;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* ----------------------------------------------------------------
   18a. Git Graph — Responsive
   ---------------------------------------------------------------- */
@media (max-width: 768px) {
  .git-row {
    gap: 1rem;
    margin-left: 0;
  }

  /* Hide description on mobile — label + name is enough */
  .git-artifact__desc {
    display: none;
  }
}

@media (max-width: 480px) {
  .git-graph {
    padding: 0 0.25rem;
  }

  .git-row {
    gap: 0;
    margin-bottom: 0.5rem;
    margin-left: 0;
  }

  .git-lanes {
    display: none;
  }

  .git-card {
    padding: 0.6rem 0.875rem;
    border-left: 3px solid var(--git-main);
    border-radius: 0 8px 8px 0;
  }

  .git-card--branch {
    border-left-color: var(--git-branch);
  }

  .git-ref {
    font-size: 0.6rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    max-width: 100%;
  }
}
.git-artifact svg {
  flex-shrink: 0;
  color: var(--color-text-secondary);
  opacity: 0.6;
}

/* ----------------------------------------------------------------
   18b. Floating Chat Bubble
   ---------------------------------------------------------------- */
.chat-bubble {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  z-index: 200;
  display: flex;
  align-items: center;
  gap: 0.6rem;
  background: var(--color-accent);
  color: #fff;
  padding: 0.55rem 1rem;
  border-radius: 2rem;
  text-decoration: none;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: var(--text-sm);
  transition: transform 0.2s ease, background 0.2s ease;
  max-width: 320px;
}

.chat-bubble:hover {
  background: var(--color-accent-light);
  transform: translateY(-3px);
  color: #fff;
}

.chat-bubble__icon {
  font-size: 1.1rem;
  flex-shrink: 0;
}

.chat-bubble--top {
  bottom: 7.5rem;
}

.chat-bubble__label {                                                                                                           
  display: none;                                                                                                              
}  

@media (max-width: 480px) {
  .chat-bubble__text { display: none; }
  .chat-bubble {
    padding: 0.875rem;
    border-radius: 50%;
    bottom: 1.5rem;
    right: 1.5rem;
  }
  .chat-bubble--top {
    bottom: 7rem;
  }
}

/* 3-column service / teaching grid variants */
.services__grid--three,
.teaching__grid--three {
  grid-template-columns: repeat(3, 1fr);
}

@media (max-width: 900px) {
  .services__grid--three,
  .teaching__grid--three {
    grid-template-columns: 1fr;
  }
}

/* ----------------------------------------------------------------
   19. Print Styles
   ---------------------------------------------------------------- */
@media print {
  .nav,
  .back-to-top,
  .hero__ticker {
    display: none;
  }

  body {
    color: #000;
    background: #fff;
  }

  a {
    color: #000;
    text-decoration: underline;
  }
}