/* ==========================================
   Personal Site — Kevin Roose Inspired
   Centered, clean, minimal, with personality
   ========================================== */

/* CSS Custom Properties */
:root {
  /* Colors — warm beige like Kevin Roose */
  --color-bg: #faf8f5;
  --color-text: #1a1a1a;
  --color-text-muted: #5c5c5c;
  --color-accent: #0066cc;
  --color-accent-hover: #0052a3;
  --color-border: #e8e4df;
  --color-surface: #ffffff;
  --color-surface-alt: #f5f3f0;
  
  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4.5rem;
  --space-4xl: 6rem;
  
  /* Layout */
  --max-width: 600px;
  --content-padding: var(--space-lg);
  
  /* Transitions */
  --transition: 200ms ease;
}

/* Dark mode - DISABLED (uncomment to enable)
@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #111111;
    --color-text: #f5f5f5;
    --color-text-muted: #999999;
    --color-accent: #66b3ff;
    --color-accent-hover: #99ccff;
    --color-border: #333333;
    --color-surface: #1a1a1a;
    --color-surface-alt: #222222;
  }
}
*/

/* ==========================================
   Reset & Base
   ========================================== */

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--space-xl);
}

body {
  margin: 0;
  padding: 0;
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.7;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Skip link */
.skip-link {
  position: absolute;
  top: -100%;
  left: var(--space-md);
  padding: var(--space-sm) var(--space-md);
  background: var(--color-text);
  color: var(--color-bg);
  text-decoration: none;
  border-radius: 4px;
  z-index: 1000;
}

.skip-link:focus {
  top: var(--space-md);
}

/* Typography */
h1, h2, h3 {
  font-family: var(--font-heading);
  font-weight: 600;
  line-height: 1.2;
  margin: 0;
}

h1 {
  font-size: 2.5rem;
  letter-spacing: -0.03em;
}

h2 {
  font-size: 1.125rem;
  font-weight: 500;
}

h3 {
  font-size: 1rem;
  font-weight: 600;
  margin-top: var(--space-xl);
  margin-bottom: var(--space-sm);
  color: var(--color-text);
}

p {
  margin: 0 0 var(--space-md) 0;
}

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

a {
  color: var(--color-accent);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
  transition: color var(--transition);
}

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

ul, ol {
  margin: 0 0 var(--space-md) 0;
  padding-left: var(--space-lg);
}

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

strong {
  font-weight: 600;
}

/* ==========================================
   Layout — Centered, Kevin Roose style
   ========================================== */

main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-3xl) var(--content-padding);
}

/* ==========================================
   Hero Section
   ========================================== */

.hero {
  text-align: center;
  margin-bottom: var(--space-3xl);
}

.hero h1 {
  margin-bottom: var(--space-sm);
}

.hero .title {
  font-size: 1.125rem;
  font-style: italic;
  color: var(--color-text-muted);
  margin-bottom: var(--space-xl);
}

.hero .bio {
  text-align: left;
  font-size: 1.0625rem;
  line-height: 1.8;
  margin-bottom: var(--space-lg);
}

.now-link-wrapper {
  text-align: center;
  margin: var(--space-xl) 0;
}

.now-link {
  display: inline-block;
  font-size: 0.9375rem;
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color var(--transition);
}

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

.now-link-separator {
  display: inline-block;
  margin: 0 0.5rem;
  color: var(--color-text-muted);
  opacity: 0.5;
}

/* Section as link (for Archive) */
.section--link {
  display: block;
  text-decoration: none;
  cursor: pointer;
  background: #f5f6f3;  /* Slightly cooler/greener than Contact */
  margin-top: var(--space-3xl);  /* Space from content above */
  margin-bottom: 0;  /* Tight with Contact below */
}

.section--link .section-link-inner {
  display: flex;
  align-items: center;
  padding: var(--space-md) var(--space-lg);
}

.section--link h2 {
  flex: 1;
  margin: 0;
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--color-text-muted);
  transition: color var(--transition);
}

.section--link:hover {
  opacity: 1;
}

.section--link:hover h2 {
  color: var(--color-text);
}

.section--link:hover .section-link-inner {
  background: var(--color-surface-alt);
}

/* ==========================================
   Subpage Links Grid (2x2 buttons)
   ========================================== */

.subpage-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-md);
  margin-top: var(--space-xl);
}

.subpage-card {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-lg) var(--space-xl);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  text-decoration: none;
  color: var(--color-text);
  transition: all var(--transition);
}

.subpage-card:hover {
  background: var(--color-surface-alt);
  border-color: var(--color-text-muted);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

.subpage-title {
  font-family: var(--font-heading);
  font-size: 1rem;
  font-weight: 500;
}

/* Subpage icons (using CSS mask for colorable SVGs) */
.subpage-icon {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
  background-color: var(--color-text-muted);
  opacity: 0.35;
  -webkit-mask-image: var(--icon-url);
  mask-image: var(--icon-url);
  -webkit-mask-size: contain;
  mask-size: contain;
  -webkit-mask-repeat: no-repeat;
  mask-repeat: no-repeat;
  -webkit-mask-position: center;
  mask-position: center;
  transition: opacity var(--transition), background-color var(--transition);
}

.subpage-card:hover .subpage-icon {
  opacity: 0.6;
  background-color: var(--color-accent);
}

/* Course variant - slightly different color */
.subpage-card--course {
  background: linear-gradient(135deg, #f0f7ff 0%, #e8f4fd 100%);
  border-color: #d0e3f0;
}

.subpage-card--course:hover {
  background: linear-gradient(135deg, #e5f1fc 0%, #d8ecfa 100%);
  border-color: #a8c8e0;
}

/* Stack on mobile */
@media (max-width: 480px) {
  .subpage-grid {
    grid-template-columns: 1fr;
  }
}

/* ==========================================
   Subpages (like /now)
   ========================================== */

.page {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-3xl) var(--content-padding);
}

.page-content h1 {
  font-size: 2rem;
  margin-bottom: var(--space-sm);
}

.page-content h2 {
  font-size: 1.25rem;
  margin-top: var(--space-2xl);
  margin-bottom: var(--space-md);
}

.page-content p {
  margin-bottom: var(--space-md);
}

.page-content ul {
  margin-bottom: var(--space-md);
}

.page-content em {
  color: var(--color-text-muted);
}

.page-content hr {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: var(--space-xl) 0;
}

/* Page navigation (back link at top) */
.page-nav {
  margin-bottom: var(--space-xl);
}

.page-nav .back-link {
  font-size: 0.8125rem;
  opacity: 0.6;
}

.page-nav .back-link:hover {
  opacity: 1;
}

/* Back link for subpages */
.back-to-home {
  margin-top: var(--space-2xl);
  padding-top: var(--space-xl);
  border-top: 1px solid var(--color-border);
}

.back-link {
  display: inline-block;
  font-size: 0.875rem;
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color var(--transition), opacity var(--transition);
}

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

/* ==========================================
   Now Page Archive (subtle footer)
   ========================================== */

.now-archive {
  margin-top: var(--space-3xl);
  padding-top: var(--space-xl);
  border-top: 1px solid var(--color-border);
}

.now-archive-label {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  opacity: 0.6;
  margin: 0 0 var(--space-sm) 0;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.now-archive-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs) var(--space-md);
}

.now-archive-list li {
  margin: 0;
}

.now-archive-list a {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  opacity: 0.5;
  text-decoration: none;
  transition: opacity var(--transition), color var(--transition);
}

.now-archive-list a:hover {
  opacity: 1;
  color: var(--color-accent);
}

/* ==========================================
   Newsletter Section
   ========================================== */

.newsletter {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: var(--space-xl);
  margin-bottom: var(--space-3xl);
  text-align: center;
}

.newsletter h2 {
  font-size: 0.8125rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  margin-bottom: var(--space-sm);
}

.newsletter p {
  font-size: 0.9375rem;
  color: var(--color-text-muted);
  margin-bottom: var(--space-lg);
}

.newsletter-form {
  display: flex;
  gap: var(--space-sm);
  max-width: 400px;
  margin: 0 auto;
}

.newsletter-form input {
  flex: 1;
  padding: var(--space-sm) var(--space-md);
  font-family: inherit;
  font-size: 0.9375rem;
  border: 1px solid var(--color-border);
  border-radius: 6px;
  background: var(--color-bg);
  color: var(--color-text);
}

.newsletter-form input:focus {
  outline: 2px solid var(--color-accent);
  outline-offset: 1px;
}

.newsletter-form button {
  padding: var(--space-sm) var(--space-lg);
  font-family: inherit;
  font-size: 0.9375rem;
  font-weight: 500;
  background: var(--color-text);
  color: var(--color-bg);
  border: none;
  border-radius: 6px;
  cursor: pointer;
  transition: opacity var(--transition);
}

.newsletter-form button:hover {
  opacity: 0.85;
}

.newsletter-intro {
  font-size: 0.9375rem;
  color: var(--color-text-muted);
  margin-bottom: var(--space-md);
}

/* ==========================================
   Random Image (before feedback)
   ========================================== */

.random-image-container {
  margin-top: var(--space-3xl);
  text-align: center;
}

.random-image {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
  opacity: 0.85;
  transition: opacity var(--transition);
}

.random-image:hover {
  opacity: 1;
}

/* ==========================================
   Feedback Section (Google Form)
   ========================================== */

.feedback-section {
  margin-top: var(--space-3xl);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 8px;
}

.feedback-summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-lg) var(--space-xl);
  cursor: pointer;
  font-size: 1rem;
  font-weight: 500;
  color: var(--color-text-muted);
  list-style: none;
}

.feedback-summary::-webkit-details-marker {
  display: none;
}

.feedback-summary:hover {
  color: var(--color-text);
}

.feedback-section[open] .feedback-summary {
  color: var(--color-text);
}

.feedback-section[open] .chevron-icon {
  transform: rotate(90deg);
}

.feedback-content {
  padding: 0 var(--space-xl) var(--space-xl);
}

.feedback-content p {
  font-size: 0.9375rem;
  color: var(--color-text-muted);
  margin: 0 0 var(--space-lg) 0;
}

.feedback-section iframe {
  border-radius: 6px;
  background: var(--color-bg);
}

/* ==========================================
   Sections (Accordions)
   ========================================== */

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

.section {
  border: 1px solid var(--color-border);
  border-radius: 8px;
  background: var(--color-surface);
}

/* Hover state for sections */
.section:hover {
  border-color: var(--color-border);
}

.section summary {
  display: flex;
  align-items: center;
  padding: var(--space-lg) var(--space-xl);
  cursor: pointer;
  list-style: none;
  user-select: none;
  transition: background var(--transition);
}

.section summary::marker {
  display: none;
  content: "";
}

.section summary::-webkit-details-marker {
  display: none;
}

.section summary:hover {
  background: var(--color-surface-alt);
  border-radius: 8px;
}

.section summary:focus {
  outline: 2px solid var(--color-accent);
  outline-offset: -2px;
}

.section summary:focus:not(:focus-visible) {
  outline: none;
}

.section summary h2 {
  margin: 0;
  flex: 1;
}

/* Chevron icon (SVG) - points right, rotates 90° to point down */
.chevron-icon {
  color: var(--color-text-muted);
  transition: transform var(--transition);
  margin-left: auto;
}

.section[open] .chevron-icon {
  transform: rotate(90deg);
}

/* Compact section variant (for contact at bottom) */
.section--compact {
  margin-top: var(--space-md);
  background: #f7f5f2;  /* Slightly warmer than page bg */
  border: 1px solid var(--color-border);
  opacity: 0.85;
}

.section--compact:hover {
  opacity: 1;
}

.section--compact summary {
  padding: var(--space-md) var(--space-lg);
}

.section--compact summary h2 {
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--color-text-muted);
}

.section--compact summary:hover h2 {
  color: var(--color-text);
}

.section--compact .section-content {
  padding: var(--space-md) var(--space-lg) var(--space-lg);
}

.section--compact .section-content p,
.section--compact .section-content li {
  font-size: 0.9375rem;
}

/* Simple contact section (non-collapsible) */
.contact-simple {
  margin-top: var(--space-md);
  padding: var(--space-md) var(--space-lg);
  text-align: center;
  font-size: 0.9375rem;
  color: var(--color-text-muted);
}

.contact-simple p {
  margin: 0;
}

.contact-simple a {
  color: var(--color-text);
}

.section-content {
  padding: var(--space-lg) var(--space-xl) var(--space-xl);
}

.section-content > *:first-child {
  margin-top: 0;
}

/* ==========================================
   Content Elements
   ========================================== */

/* Item lists (for writing, speaking, etc.) */
.item-list {
  list-style: none;
  padding: 0;
  margin: var(--space-md) 0 0 0;
}

.item-list li {
  padding: var(--space-md) 0;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: 0;
}

.item-list li:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.item-list > li > a {
  display: block;
  font-weight: 500;
  margin-bottom: var(--space-xs);
}

.item-list .meta a {
  display: inline;
  font-weight: 400;
}

.item-list .item-title {
  display: inline;
  font-weight: 500;
  color: var(--color-text);
}

.item-list .item-title-link {
  display: inline;
  font-weight: 500;
}

.item-list .item-year {
  display: inline;
  font-size: 0.875rem;
  font-weight: 400;
  color: var(--color-text-muted);
  margin-left: 0.35em;
}

.item-list .meta {
  display: block;
  font-size: 0.875rem;
  color: var(--color-text-muted);
}

/* Papers list (for research page) */
.papers-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.paper-item {
  padding: var(--space-lg) 0;
  border-bottom: 1px solid var(--color-border);
}

.paper-item:first-child {
  padding-top: 0;
}

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

.paper-title {
  display: block;
  font-weight: 600;
  font-size: 1rem;
  line-height: 1.4;
  margin-bottom: var(--space-xs);
  color: var(--color-text);
}

.paper-coauthors {
  display: block;
  font-size: 0.875rem;
  font-style: italic;
  color: var(--color-text-muted);
  margin-bottom: var(--space-xs);
}

.paper-journal {
  display: block;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-muted);
  margin-bottom: var(--space-sm);
}

.paper-links {
  display: block;
  font-size: 0.8125rem;
}

.paper-links a {
  color: var(--color-accent);
  text-decoration: none;
}

.paper-links a:hover {
  text-decoration: underline;
}

/* Cards (for books, projects) */
.card {
  padding: var(--space-lg);
  margin: var(--space-md) 0;
  background: var(--color-surface);
  border-radius: 8px;
  border: 1px solid var(--color-border);
}

.card:first-child {
  margin-top: 0;
}

.card h3 {
  margin: 0 0 var(--space-sm) 0;
}

.card p {
  font-size: 0.9375rem;
  color: var(--color-text-muted);
  margin-bottom: var(--space-sm);
}

.card a {
  font-size: 0.875rem;
  font-weight: 500;
}

/* Featured card (like Kevin Roose's upcoming book) */
.card--featured {
  background: var(--color-text);
  color: var(--color-bg);
  border-color: var(--color-text);
}

.card--featured h3 {
  color: var(--color-bg);
}

.card--featured p {
  color: rgba(255, 255, 255, 0.75);
}

.card--featured a {
  color: var(--color-bg);
  opacity: 0.9;
}

.card--featured .badge {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: var(--space-xs) var(--space-sm);
  background: rgba(255, 255, 255, 0.15);
  border-radius: 4px;
  margin-bottom: var(--space-sm);
}

/* ==========================================
   Images
   ========================================== */

figure {
  margin: var(--space-xl) 0;
  padding: 0;
}

figure img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 8px;
  background: var(--color-surface);
}

figcaption {
  margin-top: var(--space-sm);
  font-size: 0.875rem;
  color: var(--color-text-muted);
  text-align: center;
}

/* ==========================================
   FAQ Items (nested details)
   ========================================== */

.faq-item {
  border: 1px solid var(--color-border);
  border-radius: 6px;
  margin-bottom: var(--space-sm);
  background: var(--color-bg);
}

.faq-item summary {
  padding: var(--space-md);
  cursor: pointer;
  list-style: none;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary:hover {
  background: var(--color-surface-alt);
}

.faq-item[open] summary {
  border-bottom: 1px solid var(--color-border);
}

.faq-item p {
  padding: var(--space-md);
  margin: 0;
  font-size: 0.9375rem;
  color: var(--color-text-muted);
}

/* ==========================================
   Sub-Accordion (nested within sections)
   ========================================== */

.sub-accordion {
  margin-top: var(--space-xl);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  background: var(--color-bg);
}

.sub-accordion summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-md) var(--space-lg);
  cursor: pointer;
  list-style: none;
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--color-text-muted);
  transition: color var(--transition), background var(--transition);
}

.sub-accordion summary::-webkit-details-marker {
  display: none;
}

.sub-accordion summary::marker {
  display: none;
  content: "";
}

.sub-accordion summary:hover {
  color: var(--color-text);
  background: var(--color-surface-alt);
}

.sub-accordion summary .chevron-icon {
  transition: transform var(--transition);
}

.sub-accordion[open] summary .chevron-icon {
  transform: rotate(90deg);
}

.sub-accordion[open] summary {
  border-bottom: 1px solid var(--color-border);
}

.sub-accordion-content {
  padding: var(--space-md) var(--space-lg) var(--space-lg);
}

.sub-accordion-content .card:first-child {
  margin-top: 0;
}

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

footer {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-2xl) var(--content-padding) var(--space-3xl);
  text-align: center;
}

.footer-main {
  padding-bottom: var(--space-xl);
  border-bottom: 1px solid var(--color-border);
  margin-bottom: var(--space-xl);
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: var(--space-lg);
  margin-bottom: var(--space-md);
}

.footer-links a {
  font-size: 0.9375rem;
  color: var(--color-text-muted);
  text-decoration: none;
}

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

.footer-meta {
  font-size: 0.8125rem;
  color: var(--color-text-muted);
  margin: 0;
}

.footer-fun {
  font-size: 0.8125rem;
  color: var(--color-text-muted);
}

.footer-fun p {
  margin: 0;
}

/* ==========================================
   Responsive
   ========================================== */

@media (min-width: 640px) {
  :root {
    --content-padding: var(--space-xl);
  }
  
  h1 {
    font-size: 3rem;
  }
  
  .hero .title {
    font-size: 1.25rem;
  }
}

@media (max-width: 480px) {
  .newsletter-form {
    flex-direction: column;
  }
  
  .newsletter-form input,
  .newsletter-form button {
    width: 100%;
  }
}

/* ==========================================
   Reduced Motion
   ========================================== */

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  
  *, *::before, *::after {
    transition-duration: 0.01ms !important;
  }
}

/* ==========================================
   Print
   ========================================== */

@media print {
  body {
    background: white;
    color: black;
  }
  
  .skip-link,
  .newsletter {
    display: none;
  }
  
  .section {
    border: none;
    background: transparent;
  }
  
  .chevron-icon {
    display: none;
  }
  
  .section summary {
    padding: var(--space-md) 0;
  }
  
  .section-content {
    padding: 0;
  }
  
  a {
    color: inherit;
    text-decoration: underline;
  }
}