/**
 * CS Techy Newsletter — Apple UI Design System Stylesheet
 * "Human Who Codes Newsletter Layout × Apple UI Design System"
 *
 * Implements:
 * 1. apple-ui-design: SF Pro typography hierarchy, #ffffff/#f5f5f7 light mode, #000000/#1d1d1f dark mode,
 *    #0071e3 Apple blue pill buttons, frosted glass cards, 4/8/16/24/48/96px spacing, and fadeUp transitions.
 * 2. modern-web-guidance (dark-mode & dark-mode-toggle): color-scheme meta mapping, light-dark() with @media fallback.
 * 3. modern-web-guidance (validate-input-after-interaction): :user-invalid, :user-valid, adjacent .error-msg, .user-invalid-fallback.
 */

/* ==========================================================================
   1. Apple UI Design Tokens & Color Scheme Mapping
   ========================================================================== */
:root {
  /* MANDATORY (dark-mode-toggle): Base stays light dark; map <meta name="color-scheme"> back to CSS */
  color-scheme: light dark;

  &:has(> head > meta[name="color-scheme"][content="dark"]) {
    color-scheme: dark;
  }
  &:has(> head > meta[name="color-scheme"][content="light"]) {
    color-scheme: light;
  }

  /* Apple Font Stack & Hierarchy */
  --font-sans: -apple-system, BlinkMacSystemFont, 'SF Pro Display', 'SF Pro Text', 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --font-serif: Charter, 'New York', 'Bitstream Charter', Georgia, serif;
  --font-mono: 'SF Mono', ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  --font-reading: var(--font-sans);

  --text-hero: 600 48px/1.1 var(--font-sans);
  --text-title: 600 32px/1.2 var(--font-sans);
  --text-body: 400 17px/1.5 var(--font-sans);
  --text-caption: 400 13px/1.4 var(--font-sans);

  /* Apple Spacing System (4 / 8 / 16 / 24 / 48 / 96px) */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 48px;
  --space-2xl: 96px;

  /* Apple Color Primitives — Light Mode (Default) */
  --bg-primary-light: #ffffff;
  --bg-secondary-light: #f5f5f7;
  --text-primary-light: #1d1d1f;
  --text-secondary-light: #86868b;
  --accent-light: #0071e3;
  --link-light: #0066cc;
  --card-bg-light: rgba(255, 255, 255, 0.8);
  --card-border-light: rgba(0, 0, 0, 0.05);
  --card-shadow-light: 0 4px 24px rgba(0, 0, 0, 0.06);
  --divider-light: rgba(0, 0, 0, 0.08);
  --input-bg-light: #ffffff;
  --input-border-light: rgba(0, 0, 0, 0.16);

  /* Apple Color Primitives — Dark Mode */
  --bg-primary-dark: #000000;
  --bg-secondary-dark: #1d1d1f;
  --text-primary-dark: #f5f5f7;
  --text-secondary-dark: #86868b;
  --accent-dark: #0071e3;
  --link-dark: #2997ff;
  --card-bg-dark: rgba(29, 29, 31, 0.8);
  --card-border-dark: rgba(255, 255, 255, 0.08);
  --card-shadow-dark: 0 8px 32px rgba(0, 0, 0, 0.45);
  --divider-dark: rgba(255, 255, 255, 0.1);
  --input-bg-dark: #1d1d1f;
  --input-border-dark: rgba(255, 255, 255, 0.2);

  /* Validation & Semantic Colors */
  --danger-light: #d93025;
  --danger-dark: #ff453a;
  --danger-bg-light: #fce8e6;
  --danger-bg-dark: rgba(255, 69, 58, 0.14);
  --success-light: #188038;
  --success-dark: #30d158;

  /* Active Token Assignments (Light Default) */
  --bg-primary: var(--bg-primary-light);
  --bg-secondary: var(--bg-secondary-light);
  --text-primary: var(--text-primary-light);
  --text-secondary: var(--text-secondary-light);
  --accent: var(--accent-light);
  --link-color: var(--link-light);
  --card-bg: var(--card-bg-light);
  --card-border: var(--card-border-light);
  --card-shadow: var(--card-shadow-light);
  --divider: var(--divider-light);
  --input-bg: var(--input-bg-light);
  --input-border: var(--input-border-light);
  --danger: var(--danger-light);
  --danger-bg: var(--danger-bg-light);
  --success: var(--success-light);

  /* MANDATORY Fallback for browsers without light-dark() support */
  @media (prefers-color-scheme: dark) {
    --bg-primary: var(--bg-primary-dark);
    --bg-secondary: var(--bg-secondary-dark);
    --text-primary: var(--text-primary-dark);
    --text-secondary: var(--text-secondary-dark);
    --accent: var(--accent-dark);
    --link-color: var(--link-dark);
    --card-bg: var(--card-bg-dark);
    --card-border: var(--card-border-dark);
    --card-shadow: var(--card-shadow-dark);
    --divider: var(--divider-dark);
    --input-bg: var(--input-bg-dark);
    --input-border: var(--input-border-dark);
    --danger: var(--danger-dark);
    --danger-bg: var(--danger-bg-dark);
    --success: var(--success-dark);
  }

  /* Modern light-dark() token binding (follows color-scheme on :root) */
  @supports (color: light-dark(white, black)) {
    --bg-primary: light-dark(var(--bg-primary-light), var(--bg-primary-dark));
    --bg-secondary: light-dark(var(--bg-secondary-light), var(--bg-secondary-dark));
    --text-primary: light-dark(var(--text-primary-light), var(--text-primary-dark));
    --text-secondary: light-dark(var(--text-secondary-light), var(--text-secondary-dark));
    --accent: light-dark(var(--accent-light), var(--accent-dark));
    --link-color: light-dark(var(--link-light), var(--link-dark));
    --card-bg: light-dark(var(--card-bg-light), var(--card-bg-dark));
    --card-border: light-dark(var(--card-border-light), var(--card-border-dark));
    --divider: light-dark(var(--divider-light), var(--divider-dark));
    --input-bg: light-dark(var(--input-bg-light), var(--input-bg-dark));
    --input-border: light-dark(var(--input-border-light), var(--input-border-dark));
    --danger: light-dark(var(--danger-light), var(--danger-dark));
    --danger-bg: light-dark(var(--danger-bg-light), var(--danger-bg-dark));
    --success: light-dark(var(--success-light), var(--success-dark));
  }

  accent-color: var(--accent);
}

html[data-reading-font="serif"] {
  --font-reading: var(--font-serif);
}

/* ==========================================================================
   2. Base Reset, Animations & Apple Typography
   ========================================================================== */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body.cs-body {
  margin: 0;
  min-height: 100vh;
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  font: var(--text-body);
  letter-spacing: -0.011em;
  overflow-x: hidden;
  transition: background-color 0.3s cubic-bezier(0.25, 0.1, 0.25, 1), color 0.3s cubic-bezier(0.25, 0.1, 0.25, 1);
}

::selection {
  background-color: rgba(0, 113, 227, 0.2);
  color: var(--text-primary);
}

a {
  color: inherit;
  text-decoration: none;
  transition: all 0.3s cubic-bezier(0.25, 0.1, 0.25, 1);
}

img,
svg {
  max-width: 100%;
  display: block;
}

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

.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;
}

.skip-link:focus {
  position: fixed;
  top: var(--space-md);
  left: var(--space-md);
  width: auto;
  height: auto;
  clip: auto;
  z-index: 9999;
  padding: 12px 24px;
  background: var(--accent);
  color: #ffffff;
  font-weight: 500;
  border-radius: 980px;
}

/* ==========================================================================
   3. Apple UI Core Patterns: Cards, Buttons & Containers
   ========================================================================== */
.cs-container {
  width: 100%;
  max-width: 840px;
  margin-inline: auto;
  padding-inline: var(--space-lg);
}

.cs-container-reading {
  max-width: 680px;
}

.cs-container-wide {
  max-width: 980px;
}

.card {
  background: var(--card-bg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-radius: 18px;
  border: 1px solid var(--card-border);
  box-shadow: var(--card-shadow);
  transition: all 0.3s cubic-bezier(0.25, 0.1, 0.25, 1);
  animation: fadeUp 0.45s cubic-bezier(0.25, 0.1, 0.25, 1) both;
}

.btn-primary,
.cs-btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  background: var(--accent);
  color: #ffffff;
  padding: 12px 24px;
  min-height: 44px;
  border-radius: 980px;
  border: none;
  font-family: var(--font-sans);
  font-size: 15px;
  font-weight: 500;
  line-height: 1.2;
  cursor: pointer;
  white-space: nowrap;
  transition: all 0.2s ease;
}

.btn-primary:hover,
.cs-btn-primary:hover {
  transform: scale(1.02);
  filter: brightness(1.1);
  color: #ffffff;
}

.cs-btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  background: var(--bg-primary);
  color: var(--text-primary);
  padding: 12px 24px;
  min-height: 44px;
  border-radius: 980px;
  border: 1px solid var(--divider);
  font-family: var(--font-sans);
  font-size: 15px;
  font-weight: 500;
  line-height: 1.2;
  cursor: pointer;
  transition: all 0.2s ease;
}

.cs-btn-secondary:hover {
  border-color: var(--accent);
  color: var(--link-color);
  transform: scale(1.02);
}

.cs-eyebrow {
  display: inline-block;
  font: var(--text-caption);
  font-weight: 600;
  color: var(--link-color);
  margin-bottom: var(--space-xs);
}

.cs-text-caption {
  font: var(--text-caption);
  color: var(--text-secondary);
}

.cs-link-arrow {
  font-size: 15px;
  font-weight: 500;
  color: var(--link-color);
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
}

.cs-link-arrow:hover {
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* ==========================================================================
   4. Apple Translucent Sticky Header & Navigation
   ========================================================================== */
.cs-topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--card-bg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--divider);
}

.cs-topbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 52px;
  gap: var(--space-md);
  flex-wrap: wrap;
}

.cs-brand-link {
  font-size: 18px;
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  min-height: 44px;
  display: inline-flex;
  align-items: center;
}

.cs-primary-nav {
  display: flex;
  align-items: center;
}

.cs-nav-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-xs);
}

.cs-nav-link {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0 14px;
  border-radius: 980px;
  font-size: 14px;
  font-weight: 400;
  color: var(--text-secondary);
}

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

.cs-nav-link.is-active {
  color: var(--text-primary);
  font-weight: 600;
  background: rgba(0, 113, 227, 0.08);
}

.cs-topbar-controls {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.cs-font-toggle,
.cs-theme-toggle {
  appearance: none;
  background: transparent;
  border: 1px solid var(--divider);
  color: var(--text-primary);
  border-radius: 980px;
  min-width: 44px;
  min-height: 44px;
  padding: 0 12px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 500;
  transition: all 0.2s ease;
}

.cs-font-toggle:hover,
.cs-theme-toggle:hover {
  background: rgba(0, 113, 227, 0.08);
  border-color: var(--accent);
  color: var(--link-color);
}

.cs-theme-opt {
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

/*
  Non-color visibility branching for the theme toggle button (dark-mode-toggle guide):
  Default (light): show "Switch to dark" (.cs-theme-opt-dark), hide "Switch to light" (.cs-theme-opt-light).
  Dark active: hide .cs-theme-opt-dark, show .cs-theme-opt-light.
*/
.cs-theme-opt-light {
  display: none;
}

@media (prefers-color-scheme: dark) {
  :root:not(:has(> head > meta[name="color-scheme"][content="light"])) .cs-theme-opt-dark {
    display: none;
  }
  :root:not(:has(> head > meta[name="color-scheme"][content="light"])) .cs-theme-opt-light {
    display: inline-flex;
  }
}

:root:has(> head > meta[name="color-scheme"][content="dark"]) .cs-theme-opt-dark {
  display: none;
}

:root:has(> head > meta[name="color-scheme"][content="dark"]) .cs-theme-opt-light {
  display: inline-flex;
}

/* ==========================================================================
   5. Human Who Codes Inspired Author Profile Header Card
   ========================================================================== */
.cs-author-header-card {
  margin-top: var(--space-lg);
  margin-bottom: var(--space-lg);
  padding: var(--space-lg) 32px;
}

.cs-author-top {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
}

.cs-author-avatar-wrap {
  flex-shrink: 0;
}

.cs-author-avatar {
  width: 76px;
  height: 76px;
  border-radius: 50%;
  box-shadow: 0 4px 16px rgba(0, 113, 227, 0.18);
}

.cs-author-name {
  margin: 0;
  font: var(--text-title);
  letter-spacing: -0.02em;
}

.cs-author-name a:hover {
  color: var(--link-color);
}

.cs-author-byline {
  margin: var(--space-xs) 0 0;
  font-size: 15px;
  font-weight: 500;
  color: var(--text-secondary);
}

.cs-author-bio {
  margin: var(--space-md) 0 var(--space-lg);
  font: var(--text-body);
  color: var(--text-secondary);
}

.cs-author-subscribe-box {
  padding-top: var(--space-md);
  border-top: 1px solid var(--divider);
}

/* ==========================================================================
   6. Newsletter Form & Validation (modern-web-guidance: validate-input-after-interaction)
   ========================================================================== */
.cs-newsletter-form {
  width: 100%;
}

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

@media (min-width: 640px) {
  .cs-newsletter-row {
    flex-direction: row;
    align-items: flex-end;
  }
}

.cs-newsletter-field {
  flex: 1;
  min-width: 0;
}

.cs-newsletter-label {
  display: block;
  font-size: 14px;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--space-xs);
}

.hint {
  display: block;
  font: var(--text-caption);
  color: var(--text-secondary);
  margin-bottom: var(--space-sm);
}

.cs-newsletter-input {
  width: 100%;
  min-height: 44px;
  padding: 10px 16px;
  font-family: var(--font-sans);
  font-size: 16px;
  color: var(--text-primary);
  background-color: var(--input-bg);
  border: 1px solid var(--input-border);
  border-radius: 12px;
  outline: none;
  transition: all 0.2s ease;
}

.cs-newsletter-input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 4px rgba(0, 113, 227, 0.16);
}

.error-msg {
  display: none;
  color: var(--danger);
  font: var(--text-caption);
  font-weight: 500;
  margin-top: var(--space-xs);
}

/*
  MANDATORY (validate-input-after-interaction):
  Only show error styles after user interaction (:user-invalid + .user-invalid-fallback).
*/
input:user-invalid,
input.user-invalid-fallback {
  border-color: var(--danger);
  background-color: var(--danger-bg);
}

/* Reveal the error message using the adjacent sibling selector */
input:user-invalid + .error-msg,
input.user-invalid-fallback + .error-msg {
  display: block;
}

/* Positive reinforcement on :user-valid */
input:user-valid,
input.user-valid-fallback {
  border-color: var(--success);
}

.cs-newsletter-feedback {
  margin-top: var(--space-sm);
  font-size: 14px;
  font-weight: 500;
}

.cs-newsletter-feedback.is-success {
  color: var(--success);
}

.cs-newsletter-feedback.is-error {
  color: var(--danger);
}

/* ==========================================================================
   7. Featured Post Hero Card & Chronological Post Feed (index.php)
   ========================================================================== */
.cs-main {
  padding-top: var(--space-md);
  padding-bottom: var(--space-2xl);
}

.cs-featured-card {
  overflow: hidden;
  margin-bottom: var(--space-xl);
}

.cs-featured-media {
  aspect-ratio: 16 / 8.5;
  width: 100%;
  overflow: hidden;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--card-border);
}

.cs-featured-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s cubic-bezier(0.25, 0.1, 0.25, 1);
}

.cs-featured-card:hover .cs-featured-img {
  transform: scale(1.02);
}

.cs-featured-body {
  padding: var(--space-lg) 32px 32px;
}

.cs-featured-badge-bar {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-sm);
}

.cs-badge-featured {
  display: inline-flex;
  align-items: center;
  padding: 4px 12px;
  border-radius: 980px;
  background: rgba(0, 113, 227, 0.1);
  color: var(--link-color);
  font: var(--text-caption);
  font-weight: 600;
}

.cs-category-label {
  font: var(--text-caption);
  font-weight: 600;
  color: var(--link-color);
}

.cs-featured-title {
  margin: 0 0 var(--space-md);
  font: var(--text-title);
  letter-spacing: -0.02em;
}

.cs-featured-title a:hover {
  color: var(--link-color);
}

.cs-featured-excerpt {
  margin: 0 0 var(--space-lg);
  font: var(--text-body);
  color: var(--text-secondary);
}

.cs-featured-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-md);
}

.cs-post-meta {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font: var(--text-caption);
  color: var(--text-secondary);
}

.cs-reading-time {
  font: var(--text-caption);
  font-weight: 500;
  color: var(--text-secondary);
}

/* Section Headers */
.cs-feed-section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-md);
  margin-bottom: var(--space-lg);
}

.cs-section-heading,
.cs-section-title {
  margin: 0;
  font-size: 24px;
  font-weight: 600;
  letter-spacing: -0.015em;
  line-height: 1.25;
}

/* Chronological Post List */
.cs-post-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.cs-post-card {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
  padding: var(--space-lg);
}

@media (min-width: 580px) {
  .cs-post-card {
    flex-direction: row;
    align-items: center;
  }
}

.cs-post-card:hover {
  transform: translateY(-2px);
}

.cs-post-thumb-link {
  flex-shrink: 0;
}

.cs-post-thumb {
  width: 100%;
  height: 168px;
  border-radius: 14px;
  object-fit: cover;
  border: 1px solid var(--card-border);
  background: var(--bg-secondary);
}

@media (min-width: 580px) {
  .cs-post-thumb {
    width: 144px;
    height: 112px;
  }
}

.cs-post-content {
  flex: 1;
  min-width: 0;
}

.cs-post-meta-top {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-xs);
  font: var(--text-caption);
  color: var(--text-secondary);
  margin-bottom: var(--space-xs);
}

.cs-post-title {
  margin: 0 0 var(--space-sm);
  font-size: 20px;
  font-weight: 600;
  letter-spacing: -0.015em;
  line-height: 1.3;
}

.cs-post-title a:hover {
  color: var(--link-color);
}

.cs-post-excerpt {
  margin: 0;
  font-size: 15px;
  line-height: 1.5;
  color: var(--text-secondary);
}

/* Ecosystem Strip */
.cs-ecosystem-strip {
  margin-top: var(--space-xl);
}

.cs-ecosystem-cards {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-md);
}

@media (min-width: 680px) {
  .cs-ecosystem-cards {
    grid-template-columns: repeat(2, 1fr);
  }
}

.cs-eco-card {
  padding: var(--space-lg);
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.cs-eco-card:hover {
  transform: translateY(-2px);
}

.cs-eco-title {
  margin: 0;
  font-size: 19px;
  font-weight: 600;
  line-height: 1.3;
}

.cs-eco-desc {
  margin: 0 0 var(--space-xs);
  font-size: 15px;
  color: var(--text-secondary);
}

/* ==========================================================================
   8. Single Article Reading View (~680px Max Width, Apple Editorial Polish)
   ========================================================================== */
.cs-reading-progress-track {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  z-index: 100;
  background: transparent;
}

.cs-reading-progress-bar {
  height: 100%;
  width: 0%;
  background: var(--accent);
  transition: width 0.08s linear;
}

.cs-single-article {
  background: var(--bg-primary);
  border: 1px solid var(--card-border);
  border-radius: 18px;
  box-shadow: var(--card-shadow);
  padding: clamp(24px, 5vw, 48px);
  margin-bottom: var(--space-lg);
}

.cs-single-breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-md);
  font: var(--text-caption);
}

.cs-back-link {
  color: var(--text-secondary);
  font-weight: 500;
}

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

.cs-single-title {
  margin: 0 0 var(--space-lg);
  font: var(--text-hero);
  font-size: clamp(32px, 5vw, 44px);
  letter-spacing: -0.025em;
}

.cs-single-byline-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-md);
  padding: var(--space-md) 0;
  border-top: 1px solid var(--divider);
  border-bottom: 1px solid var(--divider);
  margin-bottom: var(--space-lg);
}

.cs-single-author-meta {
  display: flex;
  align-items: center;
  gap: 12px;
}

.cs-single-avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
}

.cs-single-author-name {
  font-weight: 600;
  font-size: 15px;
}

.cs-single-date-row {
  display: flex;
  align-items: center;
  gap: 6px;
  font: var(--text-caption);
  color: var(--text-secondary);
}

.cs-share-toolbar {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.cs-share-btn {
  appearance: none;
  background: var(--bg-secondary);
  border: 1px solid var(--divider);
  color: var(--text-primary);
  min-height: 38px;
  padding: 6px 14px;
  border-radius: 980px;
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 500;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  cursor: pointer;
  transition: all 0.2s ease;
}

.cs-share-btn:hover {
  border-color: var(--accent);
  color: var(--link-color);
}

.cs-single-hero-media {
  margin-bottom: var(--space-lg);
  border-radius: 14px;
  overflow: hidden;
  border: 1px solid var(--card-border);
}

.cs-single-hero-img {
  width: 100%;
  height: auto;
  max-height: 380px;
  object-fit: cover;
}

/* Editorial Content Typography */
.cs-editorial-content {
  font-family: var(--font-reading);
  font-size: 17px;
  line-height: 1.65;
  color: var(--text-primary);
}

.cs-editorial-content h2 {
  font-family: var(--font-sans);
  font: var(--text-title);
  font-size: 26px;
  letter-spacing: -0.015em;
  margin-top: var(--space-xl);
  margin-bottom: var(--space-md);
}

.cs-editorial-content h3 {
  font-family: var(--font-sans);
  font-size: 20px;
  font-weight: 600;
  margin-top: var(--space-lg);
  margin-bottom: var(--space-sm);
}

.cs-editorial-content p,
.cs-editorial-content ul,
.cs-editorial-content ol {
  margin-top: 0;
  margin-bottom: var(--space-md);
}

.cs-editorial-content a {
  color: var(--link-color);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.cs-editorial-content blockquote {
  margin: var(--space-lg) 0;
  padding: var(--space-md) var(--space-lg);
  border-left: 3px solid var(--accent);
  background: var(--bg-secondary);
  border-radius: 0 12px 12px 0;
  color: var(--text-secondary);
}

/*
  MANDATORY (modern-web-guidance: dark-mode):
  Code blocks use dark scheme; re-declare inherited accent-color on dark subtrees.
*/
pre,
code {
  color-scheme: dark;
  accent-color: var(--accent);
  font-family: var(--font-mono);
}

.cs-editorial-content :not(pre) > code {
  background: var(--bg-secondary);
  color: var(--text-primary);
  padding: 2px 6px;
  border-radius: 6px;
  font-size: 0.88em;
}

.cs-editorial-content pre {
  position: relative;
  background: #1d1d1f;
  color: #f5f5f7;
  border-radius: 14px;
  padding: 20px;
  overflow-x: auto;
  font-size: 14px;
  line-height: 1.6;
  margin: var(--space-lg) 0;
}

.cs-code-copy-btn {
  position: absolute;
  top: 10px;
  right: 10px;
  background: rgba(255, 255, 255, 0.12);
  border: 1px solid rgba(255, 255, 255, 0.18);
  color: #f5f5f7;
  border-radius: 980px;
  padding: 4px 12px;
  font-family: var(--font-sans);
  font-size: 12px;
  font-weight: 500;
  cursor: pointer;
}

.cs-code-copy-btn:hover {
  background: var(--accent);
  border-color: var(--accent);
}

.cs-single-footer {
  margin-top: var(--space-xl);
  padding-top: var(--space-lg);
  border-top: 1px solid var(--divider);
}

.cs-tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-bottom: var(--space-md);
}

.cs-tag-pill {
  padding: 4px 12px;
  border-radius: 980px;
  background: var(--bg-secondary);
  font: var(--text-caption);
  color: var(--text-secondary);
}

.cs-share-bar-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-md);
}

.cs-inline-subscribe-cta {
  padding: 32px;
  margin-bottom: var(--space-lg);
}

.cs-cta-heading {
  margin: var(--space-xs) 0 var(--space-sm);
  font-size: 24px;
  font-weight: 600;
  letter-spacing: -0.015em;
}

.cs-cta-subtext {
  margin: 0 0 var(--space-lg);
  color: var(--text-secondary);
  font-size: 15px;
}

.cs-author-footer-box {
  display: flex;
  align-items: flex-start;
  gap: var(--space-lg);
  padding: var(--space-lg) 28px;
  margin-bottom: var(--space-lg);
}

.cs-author-footer-avatar {
  width: 64px;
  height: 64px;
  border-radius: 50%;
  flex-shrink: 0;
}

.cs-author-footer-name {
  margin: 2px 0 6px;
  font-size: 20px;
  font-weight: 600;
}

.cs-author-footer-bio {
  margin: 0 0 12px;
  font-size: 15px;
  color: var(--text-secondary);
}

.cs-author-footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
  font-size: 14px;
  font-weight: 500;
  color: var(--link-color);
}

.cs-post-navigation {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: var(--space-md);
}

.cs-post-nav-item {
  padding: var(--space-lg);
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.cs-post-nav-link {
  font-weight: 600;
  font-size: 16px;
}

.cs-post-nav-link:hover {
  color: var(--link-color);
}

/* ==========================================================================
   9. About Page — Apple Bento Grid & Progressive Disclosure (page-about.php)
   ========================================================================== */
.cs-about-hero {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-xl);
  align-items: center;
  padding: var(--space-lg) 0 var(--space-xl);
}

@media (min-width: 880px) {
  .cs-about-hero {
    grid-template-columns: 1.15fr 0.85fr;
  }
}

.cs-hero-heading {
  margin: 0 0 var(--space-md);
  font: var(--text-hero);
  font-size: clamp(36px, 6vw, 48px);
  letter-spacing: -0.025em;
}

.cs-about-lead {
  margin: 0 0 var(--space-lg);
  font-size: 19px;
  line-height: 1.5;
  color: var(--text-secondary);
  max-width: 600px;
}

.cs-about-social-row {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
}

.cs-bento-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-md);
}

.cs-bento-card {
  padding: var(--space-lg);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  min-height: 160px;
}

.cs-bento-span-2 {
  grid-column: span 2;
  min-height: 140px;
}

.cs-bento-stat {
  font-size: 36px;
  font-weight: 600;
  line-height: 1.1;
  letter-spacing: -0.025em;
  color: var(--text-primary);
  margin: var(--space-sm) 0 var(--space-xs);
}

.cs-bento-location {
  font-size: 26px;
  font-weight: 600;
  letter-spacing: -0.02em;
  margin: var(--space-xs) 0;
}

.cs-bento-caption {
  font: var(--text-caption);
  color: var(--text-secondary);
}

.cs-about-split {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-xl);
  margin-bottom: var(--space-xl);
}

@media (min-width: 860px) {
  .cs-about-split {
    grid-template-columns: repeat(2, 1fr);
  }
}

.cs-stack-grid {
  margin-top: var(--space-lg);
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
}

@media (min-width: 520px) {
  .cs-stack-grid {
    grid-template-columns: repeat(4, 1fr);
  }
}

.cs-stack-tile {
  padding: var(--space-md);
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.cs-stack-tile:hover {
  transform: translateY(-2px);
}

.cs-stack-name {
  font-weight: 600;
  font-size: 15px;
}

.cs-featured-project-card {
  margin-top: var(--space-lg);
  padding: 28px;
  display: block;
}

.cs-featured-project-card:hover {
  transform: translateY(-2px);
}

.cs-featured-project-title {
  margin: var(--space-xs) 0 var(--space-sm);
  font-size: 24px;
  font-weight: 600;
  letter-spacing: -0.015em;
}

.cs-featured-project-desc {
  margin: 0 0 var(--space-md);
  color: var(--text-secondary);
  font-size: 15px;
}

/* Experience Accordion (Progressive Disclosure) */
.cs-experience-section {
  margin-bottom: var(--space-xl);
}

.cs-experience-list {
  margin-top: var(--space-lg);
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.cs-exp-item {
  overflow: hidden;
}

.cs-exp-trigger {
  width: 100%;
  appearance: none;
  background: transparent;
  border: 0;
  color: var(--text-primary);
  padding: 20px var(--space-lg);
  min-height: 64px;
  text-align: left;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-md);
  cursor: pointer;
  font-family: var(--font-sans);
}

.cs-exp-role {
  margin: 0 0 2px;
  font-size: 19px;
  font-weight: 600;
}

.cs-exp-company {
  font-size: 14px;
  color: var(--text-secondary);
}

.cs-exp-meta-group {
  display: flex;
  align-items: center;
  gap: 12px;
}

.cs-exp-date-pill {
  font: var(--text-caption);
  font-weight: 500;
  padding: 4px 12px;
  border-radius: 980px;
  background: var(--bg-secondary);
  color: var(--text-secondary);
}

.cs-exp-chevron {
  transition: transform 0.3s cubic-bezier(0.25, 0.1, 0.25, 1);
  color: var(--text-secondary);
}

.cs-exp-item.is-expanded .cs-exp-chevron {
  transform: rotate(180deg);
  color: var(--accent);
}

.cs-exp-panel {
  padding: 0 var(--space-lg) var(--space-lg);
}

.cs-exp-desc {
  margin: 0;
  color: var(--text-secondary);
  font-size: 16px;
  line-height: 1.6;
}

.cs-policy-section {
  margin-bottom: var(--space-xl);
}

.cs-policy-card {
  margin-top: var(--space-lg);
  padding: 32px;
}

.cs-contact-banner {
  padding: var(--space-xl) var(--space-lg);
  text-align: center;
}

.cs-contact-title {
  margin: 0 0 var(--space-sm);
  font: var(--text-title);
  font-size: clamp(28px, 4vw, 38px);
}

.cs-contact-sub {
  margin: 0 auto var(--space-lg);
  max-width: 500px;
  color: var(--text-secondary);
}

.cs-contact-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 12px;
}

/* ==========================================================================
   10. Playground Showcase (/lab/) & 404 Page
   ========================================================================== */
.cs-lab-hero {
  padding: var(--space-md) 0 var(--space-xl);
}

.cs-lab-section {
  margin-bottom: var(--space-xl);
}

.cs-lab-filters {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.cs-filter-btn {
  appearance: none;
  background: var(--bg-primary);
  border: 1px solid var(--divider);
  color: var(--text-secondary);
  min-height: 40px;
  padding: 8px 16px;
  border-radius: 980px;
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s ease;
}

.cs-filter-btn.is-active,
.cs-filter-btn:hover {
  background: var(--accent);
  border-color: var(--accent);
  color: #ffffff;
}

.cs-lab-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(290px, 1fr));
  gap: var(--space-md);
}

.cs-lab-card {
  padding: var(--space-lg);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 12px;
}

.cs-lab-card:hover {
  transform: translateY(-2px);
}

.cs-lab-card-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-sm);
}

.cs-lab-card-title {
  margin: 0;
  font-size: 19px;
  font-weight: 600;
  line-height: 1.3;
}

.cs-lab-card-desc {
  margin: 0;
  font-size: 15px;
  color: var(--text-secondary);
}

.cs-lab-runtime-box {
  padding: 8px 12px;
  border-radius: 10px;
  background: var(--bg-secondary);
}

/* 404 & Archive & Page Cards */
.cs-404-card,
.cs-page-card,
.cs-empty-state {
  padding: var(--space-xl) 32px;
}

.cs-archive-header {
  margin-bottom: var(--space-lg);
}

.cs-archive-title {
  margin: var(--space-xs) 0 var(--space-sm);
  font: var(--text-title);
}

.cs-404-code {
  margin: var(--space-xs) 0;
  font: var(--text-hero);
  font-size: 64px;
  color: var(--accent);
}

.cs-404-actions {
  margin-top: var(--space-lg);
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* Pagination */
.cs-pagination {
  margin-top: var(--space-xl);
}

.cs-pagination .nav-links {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  flex-wrap: wrap;
}

.cs-pagination .page-numbers {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 44px;
  min-height: 44px;
  padding: 0 14px;
  border-radius: 980px;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  font-size: 14px;
  font-weight: 500;
}

.cs-pagination .page-numbers.current {
  background: var(--accent);
  color: #ffffff;
}

/* ==========================================================================
   11. Apple-Style Minimal Footer
   ========================================================================== */
.cs-site-footer {
  border-top: 1px solid var(--divider);
  background: var(--bg-primary);
  padding: var(--space-xl) 0 var(--space-lg);
}

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

@media (min-width: 720px) {
  .cs-footer-grid {
    grid-template-columns: 1.2fr 1fr;
  }
}

.cs-footer-title {
  margin: 0 0 var(--space-xs);
  font-size: 16px;
  font-weight: 600;
}

.cs-footer-desc {
  margin: 0 0 var(--space-md);
  font: var(--text-caption);
  color: var(--text-secondary);
  max-width: 420px;
}

.cs-footer-meta-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  font: var(--text-caption);
  color: var(--link-color);
}

.cs-footer-columns {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-lg);
}

.cs-footer-heading {
  margin: 0 0 var(--space-sm);
  font: var(--text-caption);
  font-weight: 600;
  color: var(--text-primary);
}

.cs-footer-col ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  font: var(--text-caption);
  color: var(--text-secondary);
}

.cs-footer-col a:hover {
  color: var(--text-primary);
  text-decoration: underline;
}

.cs-footer-bottom {
  padding-top: var(--space-md);
  border-top: 1px solid var(--divider);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-sm);
  font: var(--text-caption);
  color: var(--text-secondary);
}