/* ==========================================================================
   Szymon Kaliski & Steph Ango Inspired Theme (Dense & Compact Layout)
   Typography: SF Pro + Helvetica / Helvetica Neue Stack
   ========================================================================== */

:root {
  --font-sans: -apple-system, BlinkMacSystemFont, "SF Pro Text", "SF Pro Display", "SF Pro", "Helvetica Neue", Helvetica, Arial, sans-serif;
  --font-mono: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace;

  /* Light Theme Palette */
  --bg: #ffffff;
  --bg-secondary: #f6f8fa;
  --bg-hover: #eaeef2;
  --text: #111111;
  --text-muted: #666666;
  --text-dim: #888888;
  --border: #e1e4e8;
  --link: #111111;
  --link-hover: #444444;
  --accent: #2b5c8f;
  --code-bg: #f3f4f6;
  --tooltip-shadow: rgba(0, 0, 0, 0.08);
}

.theme-dark {
  /* Dark Theme Palette */
  --bg: #121316;
  --bg-secondary: #1a1c23;
  --bg-hover: #252830;
  --text: #e6e8ec;
  --text-muted: #9aa0a6;
  --text-dim: #6c727c;
  --border: #2a2d37;
  --link: #e6e8ec;
  --link-hover: #ffffff;
  --accent: #64a2df;
  --code-bg: #1e2029;
  --tooltip-shadow: rgba(0, 0, 0, 0.5);
}

/* System preference fallback if no explicit theme set */
@media (prefers-color-scheme: dark) {
  :root:not(.theme-light) {
    --bg: #121316;
    --bg-secondary: #1a1c23;
    --bg-hover: #252830;
    --text: #e6e8ec;
    --text-muted: #9aa0a6;
    --text-dim: #6c727c;
    --border: #2a2d37;
    --link: #e6e8ec;
    --link-hover: #ffffff;
    --accent: #64a2df;
    --code-bg: #1e2029;
    --tooltip-shadow: rgba(0, 0, 0, 0.5);
  }
}

/* Global Reset & Base Setup */
*, *::before, *::after {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
  background-color: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 15px; /* Compact font size like Szymon's site */
  line-height: 1.48; /* Dense line spacing */
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background-color 0.2s ease, color 0.2s ease;
}

/* Container & Layout */
.site-wrapper {
  max-width: 46rem;
  margin: 0 auto;
  padding: 1.75rem 1rem 3rem; /* Compact page padding */
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  position: relative;
  z-index: 1;
}

main {
  flex: 1;
}

/* Typography & Headings */
h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  line-height: 1.25;
  margin-top: 1.5rem;
  margin-bottom: 0.5rem;
  color: var(--text);
  letter-spacing: -0.015em;
}

h1 { font-size: 1.35rem; }
h2 { font-size: 1.15rem; }
h3 { font-size: 1rem; }
h4 { font-size: 0.95rem; }

p {
  margin-top: 0;
  margin-bottom: 0.85rem;
  color: var(--text);
}

.tabular-num, time, .date-col {
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.01em;
}

/* Links & Underline Hover Effect */
a {
  color: var(--link);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
  text-decoration-color: var(--border);
  transition: color 0.15s ease, text-decoration-color 0.15s ease;
  position: relative;
  z-index: 2;
  display: inline;
}

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

a.plain {
  text-decoration: none;
}

a.plain:hover {
  text-decoration: underline;
}

/* External Link Indicator Arrow ↗ */
a.external-link::after {
  content: " ↗";
  font-size: 0.85em;
  color: var(--text-dim);
  display: inline-block;
  text-decoration: none;
  font-weight: normal;
  transition: transform 0.15s ease, color 0.15s ease;
}

a.external-link:hover::after {
  color: var(--text);
  transform: translate(1px, -1px);
}

/* Tag / Topic Badges */
.badge {
  display: inline-block;
  font-size: 0.78rem;
  padding: 0.1rem 0.4rem;
  border-radius: 4px;
  background-color: var(--bg-secondary);
  color: var(--text-muted);
  border: 1px solid var(--border);
  margin-right: 0.3rem;
  text-decoration: none;
  font-weight: 500;
}

.badge:hover {
  border-color: var(--text-muted);
  color: var(--text);
}

/* Images, Figures & Media */
img {
  max-width: 100%;
  height: auto;
  display: block;
  margin: 1.25rem 0;
  border-radius: 6px;
  border: 1px solid var(--border);
}

figure {
  margin: 1.25rem 0;
}

figure img {
  margin: 0 0 0.4rem 0;
}

figcaption {
  font-size: 0.82rem;
  color: var(--text-muted);
  text-align: center;
}

video {
  max-width: 100%;
  height: auto;
  display: block;
  border-radius: 6px;
  border: 1px solid var(--border);
  margin: 1.25rem 0;
}

/* Navigation Header (Szymon Kaliski Layout - Compact) */
header.site-header {
  margin-bottom: 1.75rem;
  padding-bottom: 0.85rem;
  border-bottom: 1px solid var(--border);
  position: relative;
  z-index: 10;
}

.header-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.65rem;
}

.site-title {
  font-size: 1.15rem;
  font-weight: 700;
  margin: 0;
  letter-spacing: -0.02em;
}

.site-title a {
  text-decoration: none;
  color: var(--text);
}

nav.main-nav {
  display: flex;
  align-items: center;
  gap: 1.1rem;
  flex-wrap: nowrap;
  overflow-x: auto;
  white-space: nowrap;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}

nav.main-nav::-webkit-scrollbar {
  display: none;
}

nav.main-nav a {
  font-size: 0.92rem;
  color: var(--text-muted);
  text-decoration: none;
  transition: color 0.15s ease;
}

nav.main-nav a:hover, nav.main-nav a.active {
  color: var(--text);
  text-decoration: underline;
  text-underline-offset: 4px;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

/* Steph Ango Signature Pill Shaped Theme Toggle */
.theme-toggle-pill {
  position: relative;
  width: 40px;
  height: 22px;
  border-radius: 9999px;
  background-color: var(--bg);
  border: 1px solid var(--border);
  padding: 2px;
  cursor: pointer;
  outline: none;
  display: inline-flex;
  align-items: center;
  transition: background-color 0.25s ease, border-color 0.25s ease;
}

.theme-toggle-pill:hover {
  border-color: var(--text-muted);
}

.theme-toggle-knob {
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background-color: transparent;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text);
  transform: translateX(0);
  transition: transform 0.25s cubic-bezier(0.4, 0, 0.2, 1), color 0.25s ease;
}

.theme-toggle-knob .icon-sun {
  display: block;
}

.theme-toggle-knob .icon-moon {
  display: none;
}

/* Dark theme state */
.theme-dark .theme-toggle-knob,
:root:not(.theme-light) .theme-toggle-knob {
  transform: translateX(18px);
}

.theme-dark .theme-toggle-knob .icon-sun,
:root:not(.theme-light) .theme-toggle-knob .icon-sun {
  display: none;
}

.theme-dark .theme-toggle-knob .icon-moon,
:root:not(.theme-light) .theme-toggle-knob .icon-moon {
  display: block;
}

/* Explicit Light theme override */
.theme-light .theme-toggle-knob {
  transform: translateX(0) !important;
}

.theme-light .theme-toggle-knob .icon-sun {
  display: block !important;
}

.theme-light .theme-toggle-knob .icon-moon {
  display: none !important;
}

/* Search Trigger Button */
.icon-btn {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-muted);
  padding: 0.25rem 0.5rem;
  border-radius: 5px;
  cursor: pointer;
  font-size: 0.82rem;
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-family: inherit;
  transition: all 0.15s ease;
}

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

kbd {
  font-family: var(--font-sans);
  font-weight: 500;
  font-size: 0.75rem;
  letter-spacing: 0.02em;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  padding: 0.1rem 0.3rem;
  border-radius: 4px;
  color: var(--text-muted);
  line-height: 1;
  display: inline-block;
}

@media (max-width: 640px) {
  .search-trigger kbd {
    display: none; /* Clean icon-only search button on mobile */
  }
}

/* Dense List Item Styles (Szymon Kaliski Style) */
.item-list {
  list-style: none;
  padding: 0;
  margin: 0.85rem 0;
}

.item-list li {
  margin-bottom: 0.85rem; /* Tight item spacing matching Szymon Kaliski's site */
  display: flex;
  align-items: baseline;
  gap: 1rem;
  line-height: 1.45;
}

.item-list .item-date {
  font-size: 0.82rem;
  color: var(--text-muted);
  font-variant-numeric: tabular-nums;
  flex-shrink: 0;
  width: 90px;
}

.item-list .item-content {
  flex: 1;
}

.item-title-wrapper {
  display: block;
  margin-bottom: 0.1rem;
}

.item-list .item-title {
  font-weight: 600;
  display: inline;
}

.item-list .item-desc {
  display: block;
  font-size: 0.88rem;
  color: var(--text-muted);
  margin-top: 0.12rem;
  margin-left: 0;
  line-height: 1.42;
}

/* Instant Search Modal */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(0, 0, 0, 0.4);
  backdrop-filter: blur(4px);
  z-index: 10000;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding-top: 10vh;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.15s ease;
}

.modal-overlay.active {
  opacity: 1;
  pointer-events: auto;
}

.search-modal-content {
  background: var(--bg);
  border: 1px solid var(--border);
  width: 90%;
  max-width: 600px;
  border-radius: 12px;
  box-shadow: 0 20px 40px var(--tooltip-shadow);
  overflow: hidden;
}

.search-input-header {
  padding: 0.85rem 1.1rem;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 0.65rem;
}

.search-input-header input {
  width: 100%;
  background: transparent;
  border: none;
  outline: none;
  font-size: 1.05rem;
  font-family: inherit;
  color: var(--text);
}

.search-results-list {
  max-height: 360px;
  overflow-y: auto;
  padding: 0.4rem 0;
  margin: 0;
  list-style: none;
}

.search-results-list li a {
  display: block;
  padding: 0.65rem 1.1rem;
  text-decoration: none;
  color: var(--text);
  transition: background 0.1s ease;
}

.search-results-list li a:hover, .search-results-list li a.selected {
  background: var(--bg-secondary);
}

.search-results-list .res-title {
  font-weight: 600;
  font-size: 0.92rem;
  margin-bottom: 0.15rem;
}

.search-results-list .res-snippet {
  font-size: 0.82rem;
  color: var(--text-muted);
}

/* Horizontal Rule Divider (Compact) */
hr {
  border: none;
  height: 1px;
  background-color: var(--border);
  margin: 1.5rem 0;
}

/* Code Blocks */
pre, code {
  font-family: var(--font-mono);
  font-size: 0.85rem;
}

code {
  background-color: var(--code-bg);
  padding: 0.12rem 0.3rem;
  border-radius: 4px;
  white-space: nowrap;
}

pre {
  background-color: var(--code-bg);
  padding: 0.85rem;
  border-radius: 6px;
  overflow-x: auto;
  border: 1px solid var(--border);
}

pre code {
  background: transparent;
  padding: 0;
  white-space: pre;
}

/* Blockquotes */
blockquote {
  margin: 1.25rem 0;
  padding-left: 0.85rem;
  border-left: 3px solid var(--accent);
  color: var(--text-muted);
  font-style: italic;
}

/* Footer */
footer.site-footer {
  margin-top: auto;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
  font-size: 0.82rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.85rem;
}

footer.site-footer a {
  color: var(--text-muted);
}

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