/* ==========================================================================
   Minimalist Design System - Idgie Kagan Portfolio
   ========================================================================== */

/*
   This file implements a complete minimalist design overhaul:
   - Refined color palette with sophisticated neutrals
   - Light typography with generous spacing
   - Consistent 8px-based spacing system
   - Subtle interactions and smooth animations
*/

/* ==========================================================================
   1. CSS Variables & Design Tokens
   ========================================================================== */

:root {
  /* Color Palette - Light & Airy */
  --color-bg-primary: #ffffff;
  --color-bg-secondary: #f8f8f8;
  --color-bg-tertiary: #f0f0f0;
  --color-gray-50: #f8f8f8;          /* For compatibility */
  --color-gray-100: #f0f0f0;         /* For compatibility */

  /* Text Colors */
  --color-text-primary: #1a1a1a;
  --color-text-secondary: #4a4a4a;
  --color-text-tertiary: #8a8a8a;

  /* Accents */
  --color-accent: #0000ff;
  --color-border: rgba(0, 0, 0, 0.1);

  /* Transparency Levels */
  --alpha-10: rgba(0, 0, 0, 0.1);
  --alpha-05: rgba(0, 0, 0, 0.05);
  --alpha-02: rgba(0, 0, 0, 0.02);

  /* Spacing Scale - 8px Grid System */
  --space-xs: 0.5rem;     /* 8px */
  --space-sm: 1rem;       /* 16px */
  --space-md: 2rem;       /* 32px */
  --space-lg: 3rem;       /* 48px */
  --space-xl: 4rem;       /* 64px */
  --space-2xl: 5rem;      /* 80px */
  --space-3xl: 8rem;      /* 128px */

  /* Typography */
  --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
  --font-serif: 'Playfair Display', Georgia, serif;

  /* Transitions */
  --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 0.6s cubic-bezier(0.4, 0, 0.2, 1);

  /* Shadows - Extremely subtle */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
}

/* Responsive Spacing Adjustments */
@media (min-width: 768px) {
  :root {
    --space-2xl: 6rem;
  }
}

@media (min-width: 1024px) {
  :root {
    --space-2xl: 7rem;
  }
}

@media (min-width: 1440px) {
  :root {
    --space-2xl: 8rem;
  }
}

/* ==========================================================================
   2. Base & Reset
   ========================================================================== */

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

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

body {
  font-family: var(--font-sans);
  font-size: clamp(1rem, 1.5vw, 1.125rem);
  font-weight: 300;
  line-height: 1.8;
  letter-spacing: 0.01em;
  color: var(--color-text-secondary);
  background: var(--color-bg-primary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

::selection {
  background: var(--alpha-10);
  color: var(--color-text-primary);
}

/* ==========================================================================
   3. Typography System
   ========================================================================== */

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-serif);
  font-weight: 300;
  color: var(--color-text-primary);
  line-height: 1.2;
  margin-bottom: var(--space-md);
}

h1 {
  font-size: clamp(2.5rem, 5vw, 4rem);
  letter-spacing: -0.02em;
  line-height: 1.1;
}

h2 {
  font-size: clamp(1.75rem, 3vw, 2.5rem);
  letter-spacing: -0.01em;
}

h3 {
  font-size: clamp(1.25rem, 2vw, 1.75rem);
  font-weight: 400;
}

h4 {
  font-size: clamp(1.1rem, 1.5vw, 1.25rem);
  font-weight: 400;
}

p {
  margin-bottom: var(--space-md);
  max-width: 65ch;
}

.caption, .meta {
  font-size: 0.875rem;
  font-weight: 400;
  letter-spacing: 0.02em;
  text-transform: uppercase;
  color: var(--color-text-tertiary);
}

a {
  color: inherit;
  text-decoration: none;
  transition: color var(--transition-base);
}

a:hover {
  color: var(--color-text-primary);
}

/* ==========================================================================
   4. Layout & Container
   ========================================================================== */

.container {
  width: 100%;
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 var(--space-md);
}

@media (min-width: 768px) {
  .container {
    padding: 0 var(--space-lg);
  }
}

.section {
  padding: var(--space-2xl) 0;
}

.section.bg-subtle {
  background-color: var(--color-bg-secondary);
}

@media (max-width: 768px) {
  .section {
    padding: var(--space-xl) 0;
  }
}

/* ==========================================================================
   5. Navigation - Minimalist
   ========================================================================== */

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  padding: var(--space-md) 0;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 1px solid transparent;
  transition: all var(--transition-base);
}

.nav.scrolled {
  background: rgba(255, 255, 255, 0.98);
  border-bottom-color: var(--color-border);
}

.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav-logo {
  font-size: 1rem;
  font-weight: 400;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text-primary);
  transition: opacity var(--transition-base);
}

.nav-logo:hover {
  opacity: 0.7;
}

.nav-menu {
  display: flex;
  gap: var(--space-md);
  list-style: none;
}

.nav-link {
  font-size: 0.875rem;
  font-weight: 400;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--color-text-secondary);
  padding: var(--space-xs) 0;
  position: relative;
  transition: color var(--transition-base);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 50%;
  width: 0;
  height: 1px;
  background: var(--color-text-primary);
  transition: all var(--transition-base);
  transform: translateX(-50%);
}

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

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

/* Mobile Navigation */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 6px;
  background: transparent;
  border: none;
  cursor: pointer;
  padding: var(--space-xs);
}

.nav-toggle span {
  width: 24px;
  height: 1px;
  background: var(--color-text-primary);
  transition: all var(--transition-base);
}

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

  .nav-menu {
    position: fixed;
    top: 0;
    right: -100%;
    width: 70%;
    max-width: 300px;
    height: 100vh;
    background: var(--color-bg-secondary);
    flex-direction: column;
    padding: var(--space-2xl) var(--space-md);
    gap: var(--space-md);
    transition: right var(--transition-base);
    border-left: 1px solid var(--color-border);
  }

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

  .nav-link::after {
    display: none;
  }
}

/* ==========================================================================
   6. Buttons & Interactive Elements
   ========================================================================== */

.btn {
  display: inline-block;
  padding: 1rem 2rem;
  background: transparent;
  border: 1px solid var(--color-border);
  color: var(--color-text-primary);
  font-size: 0.875rem;
  font-weight: 400;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  cursor: pointer;
  position: relative;
  overflow: hidden;
  transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.btn::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 0;
  height: 0;
  border-radius: 50%;
  background: var(--alpha-05);
  transform: translate(-50%, -50%);
  transition: width 0.4s ease, height 0.4s ease;
}

.btn:hover {
  border-color: var(--color-text-primary);
  transform: translateY(-2px);
}

.btn:hover::before {
  width: 300px;
  height: 300px;
}

.btn:focus-visible {
  outline: 2px solid var(--color-text-primary);
  outline-offset: 4px;
}

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

/* ==========================================================================
   7. Animations & Transitions
   ========================================================================== */

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.reveal {
  opacity: 0;
}

.reveal.active {
  animation: fadeInUp 0.4s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

/* Staggered animations for children */
.reveal-children > * {
  opacity: 0;
}

.reveal-children.active > *:nth-child(1) { animation: fadeInUp 0.3s cubic-bezier(0.4, 0, 0.2, 1) 0s forwards; }
.reveal-children.active > *:nth-child(2) { animation: fadeInUp 0.3s cubic-bezier(0.4, 0, 0.2, 1) 0.05s forwards; }
.reveal-children.active > *:nth-child(3) { animation: fadeInUp 0.3s cubic-bezier(0.4, 0, 0.2, 1) 0.1s forwards; }
.reveal-children.active > *:nth-child(4) { animation: fadeInUp 0.3s cubic-bezier(0.4, 0, 0.2, 1) 0.15s forwards; }
.reveal-children.active > *:nth-child(5) { animation: fadeInUp 0.3s cubic-bezier(0.4, 0, 0.2, 1) 0.2s forwards; }

/* Page enter animation */
@keyframes pageEnter {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

main {
  animation: pageEnter 0.3s ease-out;
}

/* Show page header content immediately */
.page-header h1,
.page-header p {
  opacity: 1;
}

/* Faster animations for elements with animate classes */
.animate-fade-in-up {
  animation: fadeInUp 0.4s ease-out forwards;
}

.animate-fade-in-up.delay-200 {
  animation-delay: 0.1s;
}

/* ==========================================================================
   8. Page Header
   ========================================================================== */

.page-header {
  padding: calc(var(--space-xl) + 60px) 0 var(--space-lg);
  text-align: center;
}

.page-header h1 {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 300;
  margin-bottom: var(--space-sm);
}

.page-header p {
  font-size: clamp(0.875rem, 1.5vw, 1rem);
  color: var(--color-text-tertiary);
  max-width: 600px;
  margin: 0 auto;
}

/* ==========================================================================
   9. Footer - Minimal
   ========================================================================== */

.footer {
  border-top: 1px solid var(--color-border);
  padding: var(--space-xl) 0 var(--space-md);
  margin-top: var(--space-2xl);
}

.footer-content {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: var(--space-xl);
  margin-bottom: var(--space-lg);
}

@media (max-width: 768px) {
  .footer-content {
    grid-template-columns: 1fr;
    gap: var(--space-md);
  }
}

.footer h3 {
  font-family: var(--font-sans);
  font-size: 0.75rem;
  font-weight: 400;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text-tertiary);
  margin-bottom: var(--space-sm);
}

.footer p {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
}

.footer-links {
  list-style: none;
}

.footer-links li {
  margin-bottom: var(--space-xs);
}

.footer-links a {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  transition: color var(--transition-base);
}

.footer-links a:hover {
  color: var(--color-text-primary);
}

.footer-social {
  display: flex;
  gap: var(--space-sm);
  margin-top: var(--space-sm);
}

.footer-social a {
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--color-border);
  border-radius: 50%;
  color: var(--color-text-secondary);
  transition: all var(--transition-base);
}

.footer-social a:hover {
  border-color: var(--color-text-primary);
  color: var(--color-text-primary);
  transform: translateY(-2px);
}

.footer-bottom {
  padding-top: var(--space-md);
  border-top: 1px solid var(--color-border);
  text-align: center;
}

.footer-bottom p {
  font-size: 0.75rem;
  color: var(--color-text-tertiary);
  margin: 0;
}

/* ==========================================================================
   10. Forms - Minimal
   ========================================================================== */

.form-group {
  margin-bottom: var(--space-lg);
}

.form-label {
  display: block;
  font-size: 0.8125rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-text-secondary);
  margin-bottom: 0.5rem;
}

.form-input,
.form-textarea {
  width: 100%;
  padding: var(--space-md) var(--space-lg);
  background: rgba(0, 0, 0, 0.02);
  border: 1px solid rgba(0, 0, 0, 0.15);
  border-radius: var(--radius-sm);
  color: var(--color-text-primary);
  font-size: 1.0625rem;
  font-family: var(--font-sans);
  transition: all var(--transition-base);
}

.form-input:hover,
.form-textarea:hover {
  border-color: rgba(0, 0, 0, 0.25);
  background: rgba(0, 0, 0, 0.04);
}

.form-input:focus,
.form-textarea:focus {
  outline: none;
  border-color: rgba(0, 0, 0, 0.4);
  background: rgba(0, 0, 0, 0.05);
  box-shadow: 0 0 0 3px rgba(0, 0, 0, 0.05);
}

.form-textarea {
  min-height: 180px;
  resize: vertical;
  line-height: 1.6;
}

.form-input::placeholder,
.form-textarea::placeholder {
  color: var(--color-text-tertiary);
}

/* ==========================================================================
   11. Images & Media
   ========================================================================== */

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

/* Image loading placeholder */
img[data-src] {
  background: var(--color-bg-tertiary);
  background-image: linear-gradient(
    90deg,
    var(--color-bg-tertiary) 0%,
    var(--alpha-05) 50%,
    var(--color-bg-tertiary) 100%
  );
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
}

@keyframes shimmer {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

img.loaded {
  animation: none;
  background: none;
  transition: opacity 0.2s ease-out;
}

/* Fade in loaded images quickly */
img[data-src].loaded {
  opacity: 1;
}

/* ==========================================================================
   12. Grid Layouts
   ========================================================================== */

.grid {
  display: grid;
  gap: var(--space-md);
}

.grid-2 {
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.grid-3 {
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
}

.grid-4 {
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
}

@media (max-width: 768px) {
  .grid-2,
  .grid-3,
  .grid-4 {
    grid-template-columns: 1fr;
  }
}

/* Content grid (text + image) */
.content-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-xl);
  align-items: center;
}

@media (max-width: 768px) {
  .content-grid {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
  }
}

/* ==========================================================================
   13. About Page Specific
   ========================================================================== */

.about-grid {
  display: grid;
  grid-template-columns: 1fr 2fr;
  gap: var(--space-xl);
  margin: var(--space-lg) 0;
}

@media (max-width: 768px) {
  .about-grid {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
  }
}

.about-image {
  width: 100%;
  height: auto;
  filter: grayscale(0.2);
  transition: filter var(--transition-slow);
}

.about-image:hover {
  filter: grayscale(0);
}

.about-content article {
  margin-bottom: var(--space-lg);
}

/* Main section headings in about content */
.about-content article > h2 {
  font-family: var(--font-serif);
  font-size: clamp(1.5rem, 2.5vw, 2rem);
  font-weight: 300;
  letter-spacing: -0.01em;
  text-transform: none;
  color: var(--color-text-primary);
  margin-bottom: var(--space-md);
}

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

.credentials-list li {
  padding: var(--space-sm) 0;
  border-bottom: 1px solid var(--color-border);
  font-size: 0.9375rem;
}

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

/* ==========================================================================
   14. Exhibition List
   ========================================================================== */

.exhibitions-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

/* Year group container */
.exhibition-year-group {
  display: flex;
  flex-direction: column;
}

/* Year header */
.year-header {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-weight: 400;
  color: var(--color-text-primary);
  margin-bottom: var(--space-sm);
  padding-bottom: var(--space-xs);
  border-bottom: 1px solid var(--color-border);
  letter-spacing: -0.01em;
}

/* Individual exhibition item - now without year column */
.exhibition-item {
  padding: var(--space-xs) 0;
  padding-left: var(--space-md);
  border-left: 2px solid transparent;
  transition: all var(--transition-base);
}

.exhibition-item:hover {
  border-left-color: var(--color-text-tertiary);
  padding-left: var(--space-md);
}

/* Old year label (deprecated, keeping for backwards compatibility) */
.exhibition-year-simple {
  font-size: 0.875rem;
  font-weight: 400;
  color: var(--color-text-tertiary);
  letter-spacing: 0.05em;
}

.exhibition-details h4 {
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  font-weight: 400;
  color: var(--color-text-primary);
  margin-bottom: 0.25rem;
  line-height: 1.4;
}

.exhibition-details h4:last-of-type {
  margin-bottom: 0.25rem;
}

.exhibition-details p {
  font-size: 0.8125rem;
  color: var(--color-text-tertiary);
  margin: 0;
  line-height: 1.5;
}

/* ==========================================================================
   15. Contact Page
   ========================================================================== */

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

@media (max-width: 968px) {
  .contact-content {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
  }
}

/* Contact form container */
.contact-form-container {
  order: 1;
}

@media (max-width: 968px) {
  .contact-form-container {
    order: 2;
  }
}

/* Contact info */
.contact-info {
  order: 2;
  position: sticky;
  top: calc(var(--space-xl) + 60px);
}

@media (max-width: 968px) {
  .contact-info {
    order: 1;
    position: relative;
    top: 0;
  }
}

.contact-info h2 {
  font-family: var(--font-serif);
  font-size: clamp(1.5rem, 2.5vw, 2rem);
  font-weight: 300;
  letter-spacing: -0.01em;
  margin-bottom: var(--space-md);
  color: var(--color-text-primary);
}

.contact-info h3 {
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 400;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--color-text-tertiary);
  margin-bottom: var(--space-sm);
}

.contact-info p {
  color: var(--color-text-secondary);
  margin-bottom: var(--space-md);
  line-height: 1.8;
}

/* Contact details list */
.contact-details {
  list-style: none;
  margin: var(--space-lg) 0;
}

.contact-details li {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) 0;
  color: var(--color-text-secondary);
  font-size: 0.9375rem;
}

.contact-details li svg {
  flex-shrink: 0;
  color: var(--color-text-tertiary);
}

.contact-details li a {
  color: var(--color-text-secondary);
  text-decoration: none;
  transition: color var(--transition-base);
}

.contact-details li a:hover {
  color: var(--color-text-primary);
}

/* Contact social icons */
.contact-social {
  display: flex;
  gap: var(--space-md);
  margin-top: var(--space-lg);
}

.contact-social a {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border: 1px solid var(--color-border);
  border-radius: 50%;
  color: var(--color-text-secondary);
  transition: all var(--transition-base);
}

.contact-social a:hover {
  color: var(--color-text-primary);
  border-color: var(--color-text-tertiary);
  transform: translateY(-2px);
}

/* Form select dropdown */
.form-select {
  width: 100%;
  padding: var(--space-md) var(--space-lg);
  background: rgba(0, 0, 0, 0.02);
  border: 1px solid rgba(0, 0, 0, 0.15);
  border-radius: var(--radius-sm);
  color: var(--color-text-primary);
  font-family: var(--font-sans);
  font-size: 1.0625rem;
  font-weight: 300;
  transition: all var(--transition-base);
  cursor: pointer;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='14' height='14' viewBox='0 0 12 12'%3E%3Cpath fill='%238a8a8a' d='M6 9L1 4h10z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right var(--space-md) center;
  padding-right: calc(var(--space-lg) + 24px);
}

.form-select:hover {
  border-color: rgba(0, 0, 0, 0.25);
  background: rgba(0, 0, 0, 0.04);
}

.form-select:focus {
  outline: none;
  border-color: rgba(0, 0, 0, 0.4);
  background: rgba(0, 0, 0, 0.05);
  box-shadow: 0 0 0 3px rgba(0, 0, 0, 0.05);
}

.form-select option {
  background: var(--color-bg-secondary);
  color: var(--color-text-primary);
  padding: var(--space-sm);
}

/* Contact form submit button */
.contact-form .btn {
  margin-top: var(--space-lg);
  width: 100%;
}

/* Form messages */
#form-messages {
  margin-bottom: var(--space-md);
  padding: var(--space-sm) var(--space-md);
  border-radius: 4px;
  font-size: 0.9375rem;
  display: none;
}

#form-messages.success {
  display: block;
  background: rgba(34, 197, 94, 0.1);
  border: 1px solid rgba(34, 197, 94, 0.3);
  color: rgb(134, 239, 172);
}

#form-messages.error {
  display: block;
  background: rgba(239, 68, 68, 0.1);
  border: 1px solid rgba(239, 68, 68, 0.3);
  color: rgb(252, 165, 165);
}

/* ==========================================================================
   16. Call to Action Sections
   ========================================================================== */

.cta-section {
  text-align: center;
  padding: var(--space-2xl) 0;
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.cta-content h2 {
  margin-bottom: var(--space-md);
}

.cta-content p {
  margin: 0 auto var(--space-lg);
  max-width: 600px;
  color: var(--color-text-secondary);
}

/* ==========================================================================
   17. Portfolio / Artworks Page
   ========================================================================== */

/* Portfolio Filters */
.portfolio-filters {
  display: flex;
  gap: var(--space-md);
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: var(--space-2xl);
  padding-bottom: var(--space-lg);
  border-bottom: 1px solid rgba(0, 0, 0, 0.08);
}

.filter-btn {
  padding: 0.75rem 1.75rem;
  background: transparent;
  color: var(--color-text-tertiary);
  border: 1px solid transparent;
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  font-weight: 400;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  cursor: pointer;
  transition: all 0.35s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
  overflow: hidden;
}

.filter-btn::before {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  width: 0;
  height: 2px;
  background: var(--color-accent);
  transition: all 0.35s cubic-bezier(0.4, 0, 0.2, 1);
  transform: translateX(-50%);
}

.filter-btn:hover {
  color: var(--color-accent);
}

.filter-btn:hover::before {
  width: 80%;
}

.filter-btn.active {
  color: var(--color-accent);
  border-color: transparent;
  background: transparent;
}

.filter-btn.active::before {
  width: 100%;
}

/* Year Section */
.year-section {
  margin-bottom: calc(var(--space-3xl) + var(--space-xl));
  opacity: 1;
  transition: opacity 0.5s cubic-bezier(0.4, 0, 0.2, 1);
  padding-bottom: var(--space-3xl);
  border-bottom: 1px solid rgba(0, 0, 0, 0.06);
  position: relative;
}

.year-section:last-of-type {
  border-bottom: none;
  padding-bottom: 0;
}

.year-section.hidden {
  display: none;
}

.year-section::after {
  content: '';
  position: absolute;
  bottom: -1px;
  left: 0;
  width: 0;
  height: 1px;
  background: linear-gradient(
    to right,
    transparent 0%,
    rgba(0, 0, 0, 0.2) 50%,
    transparent 100%
  );
  transition: width 0.8s cubic-bezier(0.4, 0, 0.2, 1);
}

.year-section:hover::after {
  width: 100%;
}

.year-section-header {
  font-family: var(--font-serif);
  font-size: clamp(2.25rem, 5vw, 3.5rem);
  font-weight: 200;
  color: var(--color-text-primary);
  margin-bottom: var(--space-2xl);
  padding-bottom: var(--space-lg);
  border-bottom: 1px solid rgba(0, 0, 0, 0.12);
  letter-spacing: -0.04em;
  line-height: 1;
  position: relative;
  padding-left: var(--space-xs);
}

.year-section-header::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  width: 2px;
  height: 100%;
  background: linear-gradient(
    to bottom,
    var(--color-text-primary) 0%,
    transparent 100%
  );
  opacity: 0.3;
}

/* Category Section */
.category-section {
  margin-bottom: var(--space-3xl);
}

.category-section:last-child {
  margin-bottom: 0;
}

.category-header {
  font-family: var(--font-sans);
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--color-text-secondary);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  margin-bottom: var(--space-xl);
  position: relative;
  padding-left: var(--space-md);
  padding-bottom: var(--space-sm);
}

.category-header::before {
  content: '';
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 2px;
  height: 14px;
  background: var(--color-text-secondary);
  opacity: 0.5;
  transition: all 0.3s ease;
}

.category-section:hover .category-header::before {
  opacity: 1;
  height: 18px;
  background: var(--color-accent);
}

/* Portfolio Grid */
.portfolio-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(400px, 1fr));
  gap: var(--space-xl);
}

@media (max-width: 768px) {
  .portfolio-grid {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
  }
}

@media (min-width: 1200px) {
  .portfolio-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* Portfolio Item */
.portfolio-item {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
  opacity: 1;
  transition: opacity var(--transition-base), transform 0.4s cubic-bezier(0.4, 0, 0.2, 1);
  text-decoration: none;
  color: inherit;
}

.portfolio-item:hover {
  transform: translateY(-4px);
}

.portfolio-item.hidden {
  display: none;
}

/* Portfolio Item as Link */
a.portfolio-item {
  cursor: pointer;
}

a.portfolio-item:hover .portfolio-info h4 {
  color: var(--color-accent);
}

/* Portfolio Image Wrapper */
.portfolio-image-wrapper {
  position: relative;
  width: 100%;
  aspect-ratio: 4 / 3;
  overflow: hidden;
  background: var(--color-bg-tertiary);
  cursor: pointer;
  border: 1px solid transparent;
  transition: border-color 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.portfolio-image-wrapper:hover {
  border-color: rgba(0, 0, 0, 0.15);
}

.portfolio-image {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.7s cubic-bezier(0.4, 0, 0.2, 1), filter 0.5s ease;
  filter: grayscale(0.15);
}

.portfolio-image-wrapper:hover .portfolio-image {
  transform: scale(1.03);
  filter: grayscale(0);
}

/* Portfolio Info */
.portfolio-info {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  padding-top: var(--space-xs);
}

.portfolio-info h3,
.portfolio-info h4 {
  font-family: var(--font-serif);
  font-size: clamp(1.125rem, 1.5vw, 1.375rem);
  font-weight: 300;
  color: var(--color-text-primary);
  line-height: 1.35;
  letter-spacing: -0.015em;
  margin: 0;
  transition: color 0.3s ease;
}

.portfolio-item:hover .portfolio-info h3,
.portfolio-item:hover .portfolio-info h4 {
  color: var(--color-accent);
}

.portfolio-series {
  font-size: 0.8125rem;
  color: var(--color-text-secondary);
  margin: 0;
  font-weight: 300;
  font-style: normal;
  line-height: 1.5;
}

.portfolio-series em {
  font-style: italic;
  color: var(--color-text-tertiary);
  font-weight: 300;
}

.portfolio-meta {
  font-size: 0.8125rem;
  color: var(--color-text-tertiary);
  margin: 0;
  font-weight: 300;
  letter-spacing: 0.02em;
}

/* Portfolio Overlay */
.portfolio-overlay {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(
    to bottom,
    rgba(0, 0, 0, 0) 0%,
    rgba(0, 0, 0, 0.4) 50%,
    rgba(0, 0, 0, 0.8) 100%
  );
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: opacity 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.portfolio-image-wrapper:hover .portfolio-overlay {
  opacity: 1;
}

.view-details {
  color: var(--color-text-primary);
  font-size: 0.75rem;
  font-weight: 400;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  padding: 0.875rem 1.5rem;
  border: 1px solid rgba(255, 255, 255, 0.6);
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(10px);
  transition: all 0.35s cubic-bezier(0.4, 0, 0.2, 1);
  transform: translateY(8px);
}

.portfolio-image-wrapper:hover .view-details {
  background: rgba(255, 255, 255, 0.95);
  border-color: rgba(0, 0, 0, 0.2);
  transform: translateY(0);
}

/* Portfolio Item Animation */
.portfolio-item.reveal {
  opacity: 0;
  transform: translateY(30px);
}

.portfolio-item.reveal.active {
  opacity: 1;
  transform: translateY(0);
}

/* Studies Grid */
.studies-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: var(--space-md);
}

@media (max-width: 768px) {
  .studies-grid {
    grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    gap: var(--space-sm);
  }
}

@media (min-width: 1200px) {
  .studies-grid {
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: var(--space-lg);
  }
}

.study-item {
  position: relative;
  width: 100%;
  aspect-ratio: 1;
  overflow: hidden;
  background: var(--color-bg-tertiary);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.study-item:hover {
  border-color: rgba(0, 0, 0, 0.15);
  transform: translateY(-2px);
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.1);
}

.study-image {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.7s cubic-bezier(0.4, 0, 0.2, 1), filter 0.5s ease;
  filter: grayscale(0.25);
}

.study-item:hover .study-image {
  transform: scale(1.08);
  filter: grayscale(0);
}

/* Hidden Study Items */
.study-item.hidden-study {
  display: none;
}

/* Show More Studies Button */
.show-more-studies-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-xs);
  margin: var(--space-xl) auto 0;
  padding: 0.875rem 2rem;
  background: transparent;
  border: 1px solid var(--color-border);
  color: var(--color-text-secondary);
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  font-weight: 400;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  cursor: pointer;
  transition: all 0.35s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
  overflow: hidden;
}

.show-more-studies-btn::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: var(--alpha-02);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1);
  z-index: -1;
}

.show-more-studies-btn:hover {
  color: var(--color-text-primary);
  border-color: var(--color-text-tertiary);
}

.show-more-studies-btn:hover::before {
  transform: scaleX(1);
}

.show-more-studies-btn .btn-icon {
  transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1);
}

.show-more-studies-btn .btn-icon.rotated {
  transform: rotate(180deg);
}

.show-more-studies-btn.expanded .btn-icon {
  transform: rotate(180deg);
}

/* Lightbox */
.lightbox {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.95);
  z-index: 10000;
  padding: var(--space-xl);
  overflow-y: auto;
}

.lightbox.active {
  display: flex;
  align-items: center;
  justify-content: center;
}

.lightbox-close {
  position: fixed;
  top: var(--space-lg);
  right: var(--space-lg);
  background: transparent;
  border: 1px solid var(--color-text-primary);
  color: var(--color-text-primary);
  font-size: 2rem;
  width: 50px;
  height: 50px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-base);
  z-index: 10001;
  line-height: 1;
  padding: 0;
}

.lightbox-close:hover {
  background: var(--alpha-10);
  transform: rotate(90deg);
}

.lightbox-content {
  max-width: 1400px;
  width: 100%;
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: var(--space-xl);
  animation: fadeInUp 0.4s ease-out;
}

@media (max-width: 968px) {
  .lightbox-content {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
  }

  .lightbox-close {
    top: var(--space-md);
    right: var(--space-md);
  }
}

.lightbox-main {
  position: relative;
}

.lightbox-main img {
  width: 100%;
  height: auto;
  display: block;
}

.lightbox-info {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.lightbox-info h2 {
  font-family: var(--font-serif);
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 300;
  color: var(--color-text-primary);
  letter-spacing: -0.01em;
  line-height: 1.2;
  margin: 0;
}

.lightbox-details {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.lightbox-details h3 {
  font-family: var(--font-sans);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-secondary);
  letter-spacing: 0.05em;
  text-transform: uppercase;
  margin: 0;
  padding-top: var(--space-md);
  border-top: 1px solid var(--color-border);
}

.detail-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
  gap: var(--space-sm);
}

.detail-grid img {
  width: 100%;
  height: auto;
  cursor: pointer;
  border: 1px solid var(--color-border);
  transition: all var(--transition-base);
}

.detail-grid img:hover {
  border-color: var(--color-text-tertiary);
  transform: scale(1.05);
}

.detail-images {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
  gap: var(--space-sm);
  margin-top: var(--space-md);
}

.detail-images img {
  width: 100%;
  height: auto;
  cursor: pointer;
  border: 1px solid var(--color-border);
  transition: all var(--transition-base);
}

.detail-images img:hover {
  border-color: var(--color-text-tertiary);
  transform: scale(1.05);
}

/* ==========================================================================
   18. Accessibility
   ========================================================================== */

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

*:focus-visible {
  outline: 2px solid var(--color-text-primary);
  outline-offset: 4px;
}

.skip-to-main {
  position: absolute;
  top: -100px;
  left: 0;
  padding: var(--space-sm) var(--space-md);
  background: var(--color-text-primary);
  color: var(--color-bg-primary);
  transition: top var(--transition-base);
  z-index: 10000;
}

.skip-to-main:focus {
  top: 0;
}

/* ==========================================================================
   17. Utility Classes
   ========================================================================== */

.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mt-sm { margin-top: var(--space-sm); }
.mt-md { margin-top: var(--space-md); }
.mt-lg { margin-top: var(--space-lg); }
.mt-xl { margin-top: var(--space-xl); }

.mb-sm { margin-bottom: var(--space-sm); }
.mb-md { margin-bottom: var(--space-md); }
.mb-lg { margin-bottom: var(--space-lg); }
.mb-xl { margin-bottom: var(--space-xl); }

.pt-sm { padding-top: var(--space-sm); }
.pt-md { padding-top: var(--space-md); }
.pt-lg { padding-top: var(--space-lg); }
.pt-xl { padding-top: var(--space-xl); }

.pb-sm { padding-bottom: var(--space-sm); }
.pb-md { padding-bottom: var(--space-md); }
.pb-lg { padding-bottom: var(--space-lg); }
.pb-xl { padding-bottom: var(--space-xl); }