/* ==========================================================================
   YYReader Official Website Stylesheet
   Modern, Clean, Reading-focused Design System
   ========================================================================== */

:root {
  /* Color Palette - Warm Paper & Slate (Light Theme) */
  --bg-canvas: #fbf9f5;
  --bg-surface: #ffffff;
  --bg-subtle: #f3efe6;
  --bg-hover: #ece6dc;

  --text-primary: #1a202c;
  --text-secondary: #4a5568;
  --text-tertiary: #718096;
  --text-inverse: #ffffff;

  --border-subtle: #e8e2d7;
  --border-strong: #d2c8b8;

  --accent-primary: #1e293b;
  --accent-primary-hover: #0f172a;
  --accent-warm: #c2410c;
  --accent-teal: #0f766e;
  --accent-blue: #0284c7;

  --badge-bg: #eef2f6;
  --badge-text: #334155;
  --badge-border: #cbd5e1;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.06), 0 1px 3px rgba(0, 0, 0, 0.03);
  --shadow-lg: 0 12px 28px rgba(0, 0, 0, 0.08), 0 2px 6px rgba(0, 0, 0, 0.04);
  --shadow-window: 0 20px 48px -10px rgba(15, 23, 42, 0.15), 0 0 1px rgba(0, 0, 0, 0.2);

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-serif: 'Noto Serif SC', "Songti SC", "Source Han Serif SC", STSong, Georgia, serif;
  --font-mono: 'JetBrains Mono', "SF Mono", Menlo, Monaco, Consolas, monospace;

  /* Spacing & Layout */
  --max-width: 1140px;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-pill: 9999px;

  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s ease;
}

[data-theme="dark"] {
  --bg-canvas: #0d1117;
  --bg-surface: #161b22;
  --bg-subtle: #1c2128;
  --bg-hover: #262c36;

  --text-primary: #f0f6fc;
  --text-secondary: #c9d1d9;
  --text-tertiary: #8b949e;
  --text-inverse: #0d1117;

  --border-subtle: #30363d;
  --border-strong: #484f58;

  --accent-primary: #38bdf8;
  --accent-primary-hover: #7dd3fc;
  --accent-warm: #fb923c;
  --accent-teal: #2dd4bf;
  --accent-blue: #38bdf8;

  --badge-bg: #21262d;
  --badge-text: #8b949e;
  --badge-border: #30363d;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.4);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.5);
  --shadow-lg: 0 12px 28px rgba(0, 0, 0, 0.6);
  --shadow-window: 0 24px 50px -10px rgba(0, 0, 0, 0.8), 0 0 1px rgba(255, 255, 255, 0.15);
}

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

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-canvas);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

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

code, kbd {
  font-family: var(--font-mono);
}

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

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

.container {
  width: 100%;
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.5rem;
  padding-right: 1.5rem;
}

/* ==========================================================================
   Header & Navigation
   ========================================================================== */

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(251, 249, 245, 0.82);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border-subtle);
  transition: background-color var(--transition-normal), border-color var(--transition-normal);
}

[data-theme="dark"] .site-header {
  background: rgba(13, 17, 23, 0.85);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 4rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.625rem;
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--text-primary);
}

.brand-logo {
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-sm);
}

.brand-name {
  letter-spacing: -0.02em;
}

.version-tag {
  font-size: 0.75rem;
  font-weight: 600;
  font-family: var(--font-mono);
  background: var(--badge-bg);
  color: var(--badge-text);
  border: 1px solid var(--badge-border);
  padding: 0.125rem 0.4rem;
  border-radius: var(--radius-pill);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.75rem;
}

.nav-link {
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: color var(--transition-fast);
  position: relative;
  padding: 0.35rem 0;
}

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

.nav-link.active::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--text-primary);
  border-radius: var(--radius-pill);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.btn-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 2.375rem;
  height: 2.375rem;
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  background: transparent;
  border: 1px solid transparent;
  transition: all var(--transition-fast);
}

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

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

.header-download-btn {
  padding: 0.5rem 1rem;
  font-size: 0.875rem;
}

.mobile-menu-btn {
  display: none;
  flex-direction: column;
  justify-content: space-between;
  width: 1.5rem;
  height: 1.125rem;
}

.mobile-menu-btn span {
  height: 2px;
  width: 100%;
  background: var(--text-primary);
  border-radius: var(--radius-pill);
  transition: all var(--transition-fast);
}

/* ==========================================================================
   Button System
   ========================================================================== */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-weight: 600;
  font-size: 0.9375rem;
  padding: 0.625rem 1.25rem;
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.btn-primary {
  background: var(--accent-primary);
  color: var(--text-inverse);
  box-shadow: var(--shadow-sm);
}

.btn-primary:hover {
  background: var(--accent-primary-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn-secondary {
  background: var(--bg-surface);
  color: var(--text-primary);
  border: 1px solid var(--border-strong);
}

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

.btn-hero {
  padding: 0.75rem 1.5rem;
  font-size: 1rem;
  border-radius: var(--radius-lg);
}

.btn-download-primary {
  background: #0f172a;
  color: #ffffff;
  box-shadow: 0 4px 14px rgba(15, 23, 42, 0.25);
  display: flex;
  align-items: center;
  gap: 0.875rem;
  text-align: left;
}

[data-theme="dark"] .btn-download-primary {
  background: #f0f6fc;
  color: #0d1117;
  box-shadow: 0 4px 14px rgba(240, 246, 252, 0.2);
}

.btn-download-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(15, 23, 42, 0.35);
}

.btn-os-icon {
  flex-shrink: 0;
}

.btn-text-wrap {
  display: flex;
  flex-direction: column;
}

.btn-label {
  font-weight: 700;
  font-size: 1rem;
  line-height: 1.2;
}

.btn-sub {
  font-size: 0.75rem;
  font-weight: 400;
  opacity: 0.85;
}

.btn-block {
  width: 100%;
}

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

.hero-section {
  padding-top: 3.5rem;
  padding-bottom: 4rem;
}

.hero-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}

.hero-badge-wrap {
  margin-bottom: 1.25rem;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--bg-surface);
  border: 1px solid var(--border-strong);
  color: var(--text-secondary);
  font-size: 0.8125rem;
  font-weight: 500;
  padding: 0.3125rem 0.875rem;
  border-radius: var(--radius-pill);
  box-shadow: var(--shadow-sm);
}

.badge-dot {
  width: 6px;
  height: 6px;
  background: #10b981;
  border-radius: 50%;
}

.hero-title {
  font-size: 2.75rem;
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.03em;
  color: var(--text-primary);
  margin-bottom: 1.25rem;
}

.hero-title-highlight {
  color: var(--accent-warm);
}

.hero-subtitle {
  font-size: 1.125rem;
  color: var(--text-secondary);
  max-width: 680px;
  margin-bottom: 2.25rem;
  line-height: 1.7;
}

.hero-cta-area {
  margin-bottom: 3.5rem;
  width: 100%;
  max-width: 620px;
}

.smart-download-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.25rem;
}

.download-btn-group {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  justify-content: center;
  width: 100%;
}

.platform-micro-badges {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.875rem;
  font-size: 0.8125rem;
  color: var(--text-tertiary);
}

.micro-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  color: var(--text-secondary);
}

.micro-badge svg {
  color: var(--accent-teal);
}

/* ==========================================================================
   Window Frame Showcase
   ========================================================================== */

.hero-media-wrapper {
  width: 100%;
  max-width: 980px;
  margin-top: 1rem;
}

.native-window-frame {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-window);
  overflow: hidden;
}

.window-titlebar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 2.25rem;
  padding: 0 1rem;
  background: var(--bg-subtle);
  border-bottom: 1px solid var(--border-subtle);
}

.window-controls {
  display: flex;
  gap: 0.45rem;
}

.window-controls .ctrl {
  width: 11px;
  height: 11px;
  border-radius: 50%;
  display: inline-block;
}

.ctrl.close { background: #ff5f56; }
.ctrl.min { background: #ffbd2e; }
.ctrl.max { background: #27c93f; }

.window-title {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-tertiary);
  font-family: var(--font-sans);
}

.window-dummy-action {
  width: 48px;
}

.window-content {
  background: #111;
  position: relative;
}

.window-img {
  width: 100%;
  height: auto;
  object-fit: cover;
  display: block;
}

/* ==========================================================================
   Section Common Styles
   ========================================================================== */

.section {
  padding: 5rem 0;
  border-top: 1px solid var(--border-subtle);
}

.section-header {
  margin-bottom: 3.5rem;
}

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

.section-badge {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--accent-warm);
  background: var(--bg-surface);
  border: 1px solid var(--border-strong);
  padding: 0.25rem 0.625rem;
  border-radius: var(--radius-pill);
  margin-bottom: 0.75rem;
}

.section-title {
  font-size: 2.125rem;
  font-weight: 700;
  letter-spacing: -0.025em;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
  line-height: 1.3;
}

.section-desc {
  font-size: 1.0625rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
  line-height: 1.65;
}

/* ==========================================================================
   Features Grid
   ========================================================================== */

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1.5rem;
}

.feature-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 2rem;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-normal);
  display: flex;
  flex-direction: column;
}

.feature-card:hover {
  transform: translateY(-3px);
  border-color: var(--border-strong);
  box-shadow: var(--shadow-md);
}

.feature-icon-box {
  width: 3rem;
  height: 3rem;
  border-radius: var(--radius-md);
  background: var(--bg-subtle);
  color: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.25rem;
}

.feature-title {
  font-size: 1.1875rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
  color: var(--text-primary);
}

.feature-text {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.feature-text code {
  font-size: 0.8125rem;
  background: var(--bg-subtle);
  padding: 0.125rem 0.35rem;
  border-radius: 4px;
}

/* ==========================================================================
   Platform Showcase
   ========================================================================== */

.showcase-tabs {
  display: inline-flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  background: var(--bg-surface);
  border: 1px solid var(--border-strong);
  padding: 0.375rem;
  border-radius: var(--radius-pill);
  margin-top: 1.75rem;
  box-shadow: var(--shadow-sm);
}

.showcase-tab {
  padding: 0.5rem 1rem;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-secondary);
  border-radius: var(--radius-pill);
  transition: all var(--transition-fast);
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
}

.showcase-tab:hover {
  color: var(--text-primary);
}

.showcase-tab.active {
  background: var(--accent-primary);
  color: var(--text-inverse);
  box-shadow: var(--shadow-sm);
}

.showcase-display-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}

.showcase-content-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  align-items: center;
}

.showcase-image-box {
  background: #111;
  border-right: 1px solid var(--border-subtle);
}

.showcase-active-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  transition: opacity 0.2s ease;
}

.showcase-info-box {
  padding: 3rem 2.5rem;
}

.showcase-badge {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--accent-teal);
  background: var(--bg-subtle);
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
  margin-bottom: 1rem;
}

.showcase-title {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 1rem;
  color: var(--text-primary);
}

.showcase-description {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 1.75rem;
}

.showcase-highlights {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.highlight-item {
  display: flex;
  align-items: flex-start;
  gap: 0.625rem;
  font-size: 0.875rem;
  color: var(--text-primary);
}

.item-check {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 18px;
  height: 18px;
  background: var(--accent-teal);
  color: #fff;
  border-radius: 50%;
  font-size: 0.6875rem;
  font-weight: bold;
  flex-shrink: 0;
  margin-top: 2px;
}

/* ==========================================================================
   Interactive Reader Sandbox Demo
   ========================================================================== */

.reader-sandbox-wrapper {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}

.sandbox-toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1rem 1.5rem;
  background: var(--bg-subtle);
  border-bottom: 1px solid var(--border-subtle);
}

.control-group {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.control-label {
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.theme-chips {
  display: flex;
  gap: 0.35rem;
}

.theme-chip {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.25rem 0.625rem;
  font-size: 0.8125rem;
  border-radius: var(--radius-pill);
  background: var(--bg-surface);
  border: 1px solid var(--border-strong);
  color: var(--text-primary);
  transition: all var(--transition-fast);
}

.theme-chip.active {
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 1px var(--accent-primary);
}

.chip-color {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  border: 1px solid rgba(0,0,0,0.15);
}

.chip-paper { background: #f6f1e7; }
.chip-light { background: #ffffff; }
.chip-mint { background: #e3ede5; }
.chip-dark { background: #1a1e24; }

.font-toggle-group, .size-stepper {
  display: flex;
  background: var(--bg-surface);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.btn-toggle, .stepper-btn {
  padding: 0.3rem 0.625rem;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: all var(--transition-fast);
}

.btn-toggle.active, .stepper-btn.active {
  background: var(--accent-primary);
  color: var(--text-inverse);
}

.size-val {
  padding: 0.3rem 0.5rem;
  font-size: 0.8125rem;
  font-family: var(--font-mono);
  font-weight: 600;
  display: flex;
  align-items: center;
  border-left: 1px solid var(--border-subtle);
  border-right: 1px solid var(--border-subtle);
  color: var(--text-primary);
}

.reader-viewport {
  padding: 3rem 1.5rem;
  min-height: 440px;
  display: flex;
  justify-content: center;
  transition: background-color var(--transition-normal);
}

/* Sandbox Themes */
.reader-viewport.theme-paper {
  background-color: #f5efe2;
  color: #2b2319;
}

.reader-viewport.theme-light {
  background-color: #ffffff;
  color: #1f2328;
}

.reader-viewport.theme-mint {
  background-color: #e5ece6;
  color: #1a271f;
}

.reader-viewport.theme-dark {
  background-color: #15191e;
  color: #d1d5db;
}

.reader-paper-sheet {
  width: 100%;
  transition: max-width var(--transition-normal);
}

.reader-paper-sheet.width-narrow { max-width: 520px; }
.reader-paper-sheet.width-normal { max-width: 680px; }
.reader-paper-sheet.width-wide { max-width: 860px; }

.reader-paper-sheet.font-serif { font-family: var(--font-serif); }
.reader-paper-sheet.font-sans { font-family: var(--font-sans); }

.reader-book-header {
  display: flex;
  justify-content: space-between;
  font-size: 0.8125rem;
  opacity: 0.65;
  margin-bottom: 2rem;
  border-bottom: 1px dashed currentColor;
  padding-bottom: 0.5rem;
}

.reader-chapter-heading {
  font-size: 1.625rem;
  font-weight: 700;
  margin-bottom: 1.5rem;
  line-height: 1.4;
}

.reader-p {
  font-size: var(--sandbox-font-size, 18px);
  line-height: 1.85;
  margin-bottom: 1.25rem;
  text-indent: 2em;
  text-align: justify;
}

.reader-footer-bar {
  margin-top: 3rem;
  padding-top: 1.5rem;
  border-top: 1px dashed currentColor;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.8125rem;
  opacity: 0.75;
}

.reader-progress-info {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.reader-progress-bar-mini {
  width: 80px;
  height: 4px;
  background: rgba(0,0,0,0.15);
  border-radius: var(--radius-pill);
  overflow: hidden;
}

.reader-viewport.theme-dark .reader-progress-bar-mini {
  background: rgba(255,255,255,0.2);
}

.progress-fill {
  height: 100%;
  background: currentColor;
}

.next-btn-fake {
  font-weight: 600;
}

/* ==========================================================================
   Folder Sync Section
   ========================================================================== */

.sync-grid {
  display: grid;
  grid-template-columns: 1fr 1.1fr;
  gap: 3.5rem;
  align-items: center;
}

.sync-features-list {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  margin-top: 2rem;
}

.sync-feat-item {
  display: flex;
  gap: 1rem;
}

.feat-bullet {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--bg-surface);
  border: 1px solid var(--border-strong);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.8125rem;
  color: var(--accent-warm);
  flex-shrink: 0;
}

.sync-feat-item h4 {
  font-size: 1.0625rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.25rem;
}

.sync-feat-item p {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.sync-diagram-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-xl);
  padding: 2rem;
  box-shadow: var(--shadow-lg);
}

.sync-folder-header {
  display: flex;
  align-items: center;
  gap: 0.625rem;
  padding-bottom: 1.25rem;
  border-bottom: 1px solid var(--border-subtle);
  margin-bottom: 1.5rem;
}

.folder-icon {
  font-size: 1.25rem;
}

.folder-name {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 1.0625rem;
}

.folder-status-pill {
  margin-left: auto;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent-teal);
  background: var(--bg-subtle);
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius-pill);
}

.sync-flow-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  margin-bottom: 1.5rem;
}

.sync-device-card {
  flex: 1;
  background: var(--bg-subtle);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.25rem 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.625rem;
}

.device-header {
  display: flex;
  align-items: center;
  gap: 0.625rem;
  margin-bottom: 0.5rem;
}

.device-text strong {
  display: block;
  font-size: 0.875rem;
  color: var(--text-primary);
}

.device-text small {
  font-size: 0.75rem;
  color: var(--text-tertiary);
}

.file-action-badge {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.75rem;
  padding: 0.35rem 0.625rem;
  border-radius: var(--radius-sm);
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
}

.file-action-badge.write {
  color: var(--accent-warm);
}

.file-action-badge.read {
  color: var(--accent-teal);
}

.file-action-badge code {
  font-weight: 600;
}

.sync-bridge {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0 0.5rem;
}

.bridge-arrow-wrap {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.35rem;
}

.bridge-badge {
  font-size: 0.6875rem;
  font-weight: 600;
  color: var(--text-tertiary);
  background: var(--bg-surface);
  border: 1px solid var(--border-strong);
  padding: 0.25rem 0.5rem;
  border-radius: var(--radius-pill);
  white-space: nowrap;
}

.sync-supported-clouds {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.8125rem;
  color: var(--text-tertiary);
  padding-top: 1rem;
  border-top: 1px solid var(--border-subtle);
}

.cloud-pill {
  background: var(--bg-subtle);
  border: 1px solid var(--border-subtle);
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
  color: var(--text-secondary);
  font-size: 0.75rem;
}

/* ==========================================================================
   Shortcuts Section
   ========================================================================== */

.shortcuts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 1.25rem;
}

.shortcut-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.key-combo {
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

kbd {
  display: inline-block;
  padding: 0.25rem 0.625rem;
  font-size: 0.9375rem;
  font-weight: 700;
  line-height: 1;
  color: var(--text-primary);
  background-color: var(--bg-subtle);
  border: 1px solid var(--border-strong);
  border-bottom: 2px solid var(--border-strong);
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-sm);
}

.shortcut-desc h4 {
  font-size: 1.0625rem;
  font-weight: 700;
  margin-bottom: 0.35rem;
  color: var(--text-primary);
}

.shortcut-desc p {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

/* ==========================================================================
   Download & Checksum Section
   ========================================================================== */

.download-cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 2rem;
}

.download-package-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-xl);
  padding: 2.25rem;
  box-shadow: var(--shadow-md);
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.pkg-header {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.pkg-icon-wrap {
  width: 3.5rem;
  height: 3.5rem;
  border-radius: var(--radius-md);
  background: var(--bg-subtle);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-primary);
}

.pkg-title-area h3 {
  font-size: 1.3125rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.25rem;
}

.pkg-badge {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent-warm);
  background: var(--bg-subtle);
  padding: 0.15rem 0.5rem;
  border-radius: var(--radius-pill);
}

.pkg-details {
  display: flex;
  flex-direction: column;
  gap: 0.625rem;
  padding: 1rem;
  background: var(--bg-subtle);
  border-radius: var(--radius-md);
  font-size: 0.875rem;
}

.detail-row {
  display: flex;
  justify-content: space-between;
}

.detail-name {
  color: var(--text-tertiary);
}

.detail-val {
  font-weight: 500;
  color: var(--text-primary);
}

.checksum-box {
  background: var(--bg-subtle);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 0.875rem;
  font-size: 0.75rem;
}

.checksum-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.35rem;
  color: var(--text-tertiary);
  font-weight: 600;
}

.copy-btn {
  font-size: 0.75rem;
  color: var(--accent-blue);
  font-weight: 600;
}

.copy-btn:hover {
  text-decoration: underline;
}

.checksum-code {
  display: block;
  word-break: break-all;
  font-family: var(--font-mono);
  color: var(--text-secondary);
}

.pkg-notice {
  font-size: 0.8125rem;
  color: var(--text-tertiary);
  line-height: 1.5;
}

/* ==========================================================================
   FAQ Section
   ========================================================================== */

.faq-accordion {
  max-width: 780px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.faq-item {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: border-color var(--transition-fast);
}

.faq-item.open {
  border-color: var(--border-strong);
}

.faq-question {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.25rem 1.5rem;
  font-size: 1.0625rem;
  font-weight: 600;
  color: var(--text-primary);
  text-align: left;
}

.faq-icon {
  font-size: 1.25rem;
  color: var(--text-tertiary);
  transition: transform var(--transition-fast);
}

.faq-item.open .faq-icon {
  transform: rotate(45deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, padding 0.3s ease;
  padding: 0 1.5rem;
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

.faq-item.open .faq-answer {
  max-height: 300px;
  padding-bottom: 1.25rem;
}

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

.site-footer {
  border-top: 1px solid var(--border-subtle);
  padding: 4rem 0 3rem;
  background: var(--bg-subtle);
}

.footer-inner {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 3rem;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  font-size: 1.125rem;
  margin-bottom: 0.75rem;
}

.footer-brand img {
  border-radius: var(--radius-sm);
}

.footer-motto {
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin-bottom: 1rem;
  max-width: 320px;
}

.footer-copy {
  font-size: 0.75rem;
  color: var(--text-tertiary);
}

.footer-links-col h4 {
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 1rem;
}

.footer-links-col ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

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

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

/* ==========================================================================
   Toast Notification
   ========================================================================== */

.toast {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: var(--accent-primary);
  color: var(--text-inverse);
  padding: 0.75rem 1.25rem;
  border-radius: var(--radius-pill);
  font-size: 0.875rem;
  font-weight: 600;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  transform: translateY(10px);
  pointer-events: none;
  transition: all 0.25s ease;
  z-index: 999;
}

.toast.show {
  opacity: 1;
  transform: translateY(0);
}

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

@media (max-width: 900px) {
  .hero-title {
    font-size: 2.25rem;
  }

  .showcase-content-grid {
    grid-template-columns: 1fr;
  }

  .showcase-image-box {
    border-right: none;
    border-bottom: 1px solid var(--border-subtle);
  }

  .showcase-info-box {
    padding: 2rem 1.5rem;
  }

  .sync-grid {
    grid-template-columns: 1fr;
    gap: 2.5rem;
  }

  .footer-inner {
    grid-template-columns: 1fr;
    gap: 2rem;
  }
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 4rem;
    left: 0;
    right: 0;
    background: var(--bg-surface);
    border-bottom: 1px solid var(--border-subtle);
    flex-direction: column;
    padding: 1.5rem;
    gap: 1rem;
    box-shadow: var(--shadow-lg);
  }

  .nav-links.open {
    display: flex;
  }

  .mobile-menu-btn {
    display: flex;
  }

  .header-download-btn {
    display: none;
  }

  .sync-flow-container {
    flex-direction: column;
  }

  .sync-bridge {
    padding: 0.5rem 0;
  }
}