/* ==========================================================================
   Guide4PC — Main Stylesheet
   Adwaita-inspired design with CSS custom properties (oklch color space).
   ========================================================================== */

/* ─── CSS Variables (non-color) ───────────────────────────────────────────── */
:root {
  /* Sizing */
  --font-size-base: 16px;
  --line-height:    1.7;
  --radius:         8px;
  --radius-sm:      4px;
  --sidebar-width:  280px;
  --topbar-height:  48px;

  /* User-adjustable (via settings panel) */
  --font-scale:     1;
  --content-width:  75%;
  --sidebar-width-dyn: 280px;

  /* Fonts */
  --font-sans:   'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-serif:  'Noto Serif SC', 'Inter', Georgia, serif;
  --font-mono:   'JetBrains Mono', 'Cascadia Code', 'Fira Code', 'Noto Sans SC', monospace;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
}

/* ─── Theme: 亮白 (Light White) — default ──────────────────────────────────── */
[data-theme="light"], :root {
  --color-bg:        oklch(0.985 0 0);
  --color-surface:   oklch(0.99 0 0);
  --color-text:      oklch(0.2 0 0);
  --color-text-muted: oklch(0.45 0 0);
  --color-primary:   oklch(0.55 0.18 255);
  --color-primary-hover: oklch(0.48 0.18 255);
  --color-border:    oklch(0.88 0 0);
  --color-border-strong: oklch(0.75 0 0);
  --color-code-bg:   oklch(0.965 0 0);
  --color-pre-bg:    oklch(0.97 0 0);
  --color-hover-bg:  oklch(0.95 0 0);
  --color-active-bg: oklch(0.9 0.15 255 / 0.15);
  --color-highlight: oklch(0.92 0.17 100);
  --color-toast-bg:  oklch(0.25 0 0);
  --color-toast-text: oklch(0.98 0 0);
  --color-backdrop:  oklch(0 0 0 / 0.3);
  --color-shadow:    oklch(0 0 0 / 0.12);
}

/* ─── Theme: 米黄 (Cream) — warm paper-book ────────────────────────────────── */
[data-theme="cream"] {
  --color-bg:        oklch(0.96 0.015 85);
  --color-surface:   oklch(0.94 0.015 85);
  --color-text:      oklch(0.23 0.015 80);
  --color-text-muted: oklch(0.44 0.02 80);
  --color-primary:   oklch(0.48 0.12 40);
  --color-primary-hover: oklch(0.4 0.12 40);
  --color-border:    oklch(0.85 0.02 85);
  --color-border-strong: oklch(0.72 0.02 85);
  --color-code-bg:   oklch(0.92 0.01 90);
  --color-pre-bg:    oklch(0.93 0.01 90);
  --color-hover-bg:  oklch(0.91 0.015 85);
  --color-active-bg: oklch(0.85 0.06 50 / 0.15);
  --color-highlight: oklch(0.88 0.14 95);
  --color-toast-bg:  oklch(0.28 0.015 80);
  --color-toast-text: oklch(0.96 0.01 90);
  --color-backdrop:  oklch(0 0 0 / 0.25);
  --color-shadow:    oklch(0 0 0 / 0.1);
}

/* ─── Theme: 暗夜 (Dark Night) — Safari-reader dark ────────────────────────── */
[data-theme="dark"] {
  --color-bg:        oklch(0.2 0.005 260);
  --color-surface:   oklch(0.24 0.005 260);
  --color-text:      oklch(0.88 0.003 260);
  --color-text-muted: oklch(0.58 0.005 260);
  --color-primary:   oklch(0.65 0.14 240);
  --color-primary-hover: oklch(0.72 0.14 240);
  --color-border:    oklch(0.3 0.005 260);
  --color-border-strong: oklch(0.4 0.005 260);
  --color-code-bg:   oklch(0.25 0.005 260);
  --color-pre-bg:    oklch(0.26 0.005 260);
  --color-hover-bg:  oklch(0.27 0.005 260);
  --color-active-bg: oklch(0.35 0.08 255 / 0.2);
  --color-highlight: oklch(0.35 0.1 90);
  --color-toast-bg:  oklch(0.85 0.003 260);
  --color-toast-text: oklch(0.2 0.005 260);
  --color-backdrop:  oklch(0 0 0 / 0.5);
  --color-shadow:    oklch(0 0 0 / 0.3);
}

/* ─── Theme: 青青 (Mint) — Morandi sage green ──────────────────────────────── */
[data-theme="green"] {
  --color-bg:        oklch(0.95 0.015 160);
  --color-surface:   oklch(0.93 0.015 160);
  --color-text:      oklch(0.25 0.015 175);
  --color-text-muted: oklch(0.45 0.015 170);
  --color-primary:   oklch(0.5 0.07 180);
  --color-primary-hover: oklch(0.42 0.07 180);
  --color-border:    oklch(0.86 0.02 160);
  --color-border-strong: oklch(0.74 0.02 160);
  --color-code-bg:   oklch(0.92 0.008 170);
  --color-pre-bg:    oklch(0.93 0.008 170);
  --color-hover-bg:  oklch(0.9 0.015 160);
  --color-active-bg: oklch(0.85 0.05 180 / 0.15);
  --color-highlight: oklch(0.88 0.1 130);
  --color-toast-bg:  oklch(0.3 0.015 175);
  --color-toast-text: oklch(0.95 0.01 160);
  --color-backdrop:  oklch(0 0 0 / 0.25);
  --color-shadow:    oklch(0 0 0 / 0.08);
}

/* ─── Reset & Base ──────────────────────────────────────────────────────── */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

/* Inline SVG icons — replacement for Font Awesome */
.icon {
  width: 1em;
  height: 1em;
  fill: currentColor;
  flex-shrink: 0;
}

html {
  font-size: var(--font-size-base);
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: var(--line-height);
  color: var(--color-text);
  background: var(--color-bg);
  display: flex;
  min-height: 100vh;
}

/* ─── Sidebar ───────────────────────────────────────────────────────────── */
.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--sidebar-width-dyn);
  height: 100vh;
  background: var(--color-surface);
  border-right: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  z-index: 100;
  overflow: hidden;
  transition: transform var(--transition-normal);
}

.sidebar-header {
  height: var(--topbar-height);
  padding: 0 0.75rem;
  border-bottom: 1px solid var(--color-border);
  background: var(--color-bg);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

/* Search */
.search-wrapper {
  flex: 1;
  position: relative;
  display: flex;
  align-items: center;
}

.search-icon {
  position: absolute;
  left: 0.625rem;
  color: var(--color-text-muted);
  font-size: 0.85rem;
  pointer-events: none;
}

.search-input {
  width: 100%;
  padding: 0.4rem 2rem 0.4rem 1.8rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  font-size: 0.875rem;
  font-family: var(--font-sans);
  background: var(--color-bg);
  color: var(--color-text);
  outline: none;
  transition: border-color var(--transition-fast);
}

.search-input:focus {
  border-color: var(--color-primary);
}

.search-clear {
  position: absolute;
  right: 0.25rem;
  background: none;
  border: none;
  color: var(--color-text-muted);
  cursor: pointer;
  font-size: 0.75rem;
  padding: 0.25rem;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
}

.search-clear:hover {
  color: var(--color-text);
  background: var(--color-hover-bg);
}

.sidebar-close {
  display: none;
  background: none;
  border: none;
  color: var(--color-text-muted);
  cursor: pointer;
  font-size: 1.1rem;
  padding: 0.25rem;
  border-radius: var(--radius-sm);
  flex-shrink: 0;
}

.sidebar-close:hover {
  color: var(--color-text);
  background: var(--color-hover-bg);
}

/* Navigation tree */
.nav-tree {
  flex: 1;
  overflow-y: auto;
  padding: 0.5rem 0;
}

.nav-tree::-webkit-scrollbar {
  width: 6px;
}

.nav-tree::-webkit-scrollbar-thumb {
  background: var(--color-border);
  border-radius: 3px;
}

/* Directory node */
.nav-dir {
  user-select: none;
}

.nav-dir-header {
  display: flex;
  align-items: center;
  padding: 0.35rem 1rem;
  cursor: pointer;
  font-size: 0.85rem;
  color: var(--color-text-muted);
  gap: 0.5rem;
  border-radius: 0;
  transition: background var(--transition-fast);
}

.nav-dir-header:hover {
  background: var(--color-hover-bg);
}

.nav-dir-header .dir-icon {
  font-size: 0.7rem;
  transition: transform var(--transition-fast);
  width: 1em;
  text-align: center;
}

.nav-dir.collapsed .nav-dir-header .dir-icon {
  transform: rotate(-90deg);
}

.nav-dir.collapsed .nav-dir-children {
  display: none;
}

.nav-dir-children {
  /* visible by default */
}

/* File node */
.nav-file {
  display: flex;
  align-items: center;
  padding: 0.35rem 1rem 0.35rem 2rem;
  cursor: pointer;
  font-size: 0.85rem;
  color: var(--color-text);
  text-decoration: none;
  border-radius: 0;
  transition: background var(--transition-fast);
  gap: 0.5rem;
}

.nav-file:hover {
  background: var(--color-hover-bg);
}

.nav-file.active {
  background: var(--color-active-bg);
  color: var(--color-primary);
  font-weight: 500;
}

.nav-file .file-icon {
  font-size: 0.7rem;
  color: var(--color-text-muted);
  flex-shrink: 0;
}

.nav-file.active .file-icon {
  color: var(--color-primary);
}

/* Search highlight in nav */
.nav-file mark {
  background: var(--color-highlight);
  color: inherit;
  border-radius: 2px;
  padding: 0 1px;
}

/* ─── Main Content Area ─────────────────────────────────────────────────── */
.main-wrapper {
  margin-left: var(--sidebar-width-dyn);
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* Top bar */
.topbar {
  position: sticky;
  top: 0;
  height: var(--topbar-height);
  display: flex;
  align-items: center;
  padding: 0 1rem;
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  z-index: 50;
  backdrop-filter: blur(8px);
  transition: transform 0.3s ease;
}

.topbar.hidden {
  transform: translateY(-100%);
}

.sidebar-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--color-text-muted);
  cursor: pointer;
  font-size: 1.1rem;
  padding: 0.35rem;
  border-radius: var(--radius-sm);
}

.sidebar-toggle:hover {
  color: var(--color-text);
  background: var(--color-hover-bg);
}

.topbar-spacer {
  flex: 1;
}

/* Language switch */
.lang-switch {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.35rem 0.75rem;
  font-size: 0.85rem;
  font-family: var(--font-sans);
  color: var(--color-primary);
  background: none;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  cursor: pointer;
  transition: background var(--transition-fast), border-color var(--transition-fast);
}

.lang-switch:hover {
  background: var(--color-hover-bg);
  border-color: var(--color-primary);
}

/* Document content */
.content {
  flex: 1;
  padding: 2rem 1.5rem;
  width: var(--content-width);
  max-width: none;
  margin: 0 auto;
  font-size: calc(1rem * var(--font-scale));
}

/* Home page (welcome) uses serif */
.content.home-page {
  font-family: var(--font-serif);
}

/* ─── Typography ────────────────────────────────────────────────────────── */
.content h1 { font-size: 1.75em; font-weight: 600; margin: 1.5em 0 0.6em; }
.content h2 { font-size: 1.35em; font-weight: 600; margin: 1.4em 0 0.5em; padding-bottom: 0.2em; border-bottom: 1px solid var(--color-border); }
.content h3 { font-size: 1.15em; font-weight: 600; margin: 1.2em 0 0.4em; }
.content h4 { font-size: 1.05em; font-weight: 600; margin: 1em 0 0.3em; }
.content h5, .content h6 { font-size: 0.95em; font-weight: 600; margin: 0.8em 0 0.2em; }

.content p { margin: 0.6em 0; }
.content a { color: var(--color-primary); text-decoration: none; }
.content a:hover { text-decoration: underline; }

.content blockquote {
  margin: 0.8em 0;
  padding: 0.5em 1em;
  border-left: 3px solid var(--color-primary);
  background: var(--color-pre-bg);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--color-text-muted);
}

.content ul, .content ol {
  margin: 0.5em 0;
  padding-left: 1.5em;
}

.content li { margin: 0.2em 0; }

.content hr {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: 1.5em 0;
}

.content table {
  border-collapse: collapse;
  width: 100%;
  margin: 1em 0;
  font-size: 0.9rem;
}

.content th, .content td {
  border: 1px solid var(--color-border);
  padding: 0.5em 0.75em;
  text-align: left;
}

.content th {
  background: var(--color-pre-bg);
  font-weight: 600;
}

.content img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-sm);
}

/* ─── Inline Code ───────────────────────────────────────────────────────── */
.content code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  background: var(--color-code-bg);
  padding: 0.15em 0.35em;
  border-radius: var(--radius-sm);
}

/* ─── Code Blocks ───────────────────────────────────────────────────────── */
.content pre {
  position: relative;
  background: var(--color-pre-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1rem;
  overflow-x: auto;
  margin: 1em 0;
  line-height: 1.5;
}

.content pre code {
  background: none;
  padding: 0;
  font-size: 0.85rem;
  border-radius: 0;
}

/* Copy button */
.copy-btn {
  position: absolute;
  top: 0.5rem;
  right: 0.5rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  color: var(--color-text-muted);
  cursor: pointer;
  font-size: 0.8rem;
  padding: 0.3rem 0.5rem;
  opacity: 0;
  transition: opacity var(--transition-fast), background var(--transition-fast);
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.content pre:hover .copy-btn {
  opacity: 1;
}

.copy-btn:hover {
  background: var(--color-hover-bg);
  color: var(--color-text);
}

/* ─── Footnotes ─────────────────────────────────────────────────────────── */
.content .footnote-ref {
  font-size: 0.8em;
  vertical-align: super;
}

.content .footnotes-list {
  margin-top: 2em;
  padding-top: 1em;
  border-top: 1px solid var(--color-border);
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

/* ─── Toast ─────────────────────────────────────────────────────────────── */
.toast-container {
  position: fixed;
  bottom: 1.5rem;
  left: 50%;
  transform: translateX(-50%);
  z-index: 1000;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  pointer-events: none;
}

.toast {
  background: var(--color-toast-bg);
  color: var(--color-toast-text);
  padding: 0.6rem 1.2rem;
  border-radius: var(--radius);
  font-size: 0.85rem;
  box-shadow: 0 4px 12px var(--color-shadow);
  animation: toast-in var(--transition-normal) ease-out,
             toast-out var(--transition-normal) 1.8s ease-in forwards;
  pointer-events: auto;
  white-space: nowrap;
}

@keyframes toast-in {
  from { opacity: 0; transform: translateY(0.5rem); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes toast-out {
  from { opacity: 1; }
  to   { opacity: 0; }
}

/* ─── Search result highlight in content ────────────────────────────────── */
.content mark.search-mark {
  background: var(--color-highlight);
  color: inherit;
  border-radius: 2px;
  padding: 0 1px;
  transition: background 3s ease;
}

.content mark.search-mark.fading {
  background: transparent;
}

/* ─── Sidebar backdrop ──────────────────────────────────────────────────── */
.sidebar-backdrop {
  position: fixed;
  inset: 0;
  background: var(--color-backdrop);
  z-index: 99;
  opacity: 1;
  transition: opacity var(--transition-normal);
}

.sidebar-backdrop.hidden {
  opacity: 0;
  pointer-events: none;
}

/* ─── Loading / Empty state ─────────────────────────────────────────────── */
.content .loading {
  text-align: center;
  padding: 3rem 0;
  color: var(--color-text-muted);
}

.content .loading .spinner {
  display: inline-block;
  width: 2rem;
  height: 2rem;
  border: 3px solid var(--color-border);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  margin-bottom: 1rem;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* ─── Footer ──────────────────────────────────────────────────────────────── */
.footer {
  text-align: center;
  padding: 0.75rem 0;
  font-size: 0.75rem;
  color: var(--color-text-muted);
  border-top: 1px solid var(--color-border);
}

.footer a {
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

/* ─── Responsive: Mobile (≤768px) ───────────────────────────────────────── */
@media (max-width: 768px) {
  .sidebar {
    transform: translateX(-100%);
  }

  .sidebar.open {
    transform: translateX(0);
  }

  .sidebar-close {
    display: flex;
  }

  .sidebar-toggle {
    display: flex;
  }

  .main-wrapper {
    margin-left: 0;
  }

  .content {
    padding: 1.25rem 1rem;
    width: 100%;
  }

  .topbar {
    padding: 0 0.75rem;
  }

  .settings-panel {
    right: 0.75rem;
  }
}

/* ─── Settings Panel ─────────────────────────────────────────────────────── */
.settings-toggle {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.35rem 0.6rem;
  font-size: 0.85rem;
  color: var(--color-text-muted);
  background: none;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  cursor: pointer;
  margin-right: 0.5rem;
  transition: background var(--transition-fast), border-color var(--transition-fast);
}

.settings-toggle:hover {
  background: var(--color-hover-bg);
  border-color: var(--color-border-strong);
}

.settings-panel {
  position: fixed;
  top: calc(var(--topbar-height) + 4px);
  right: 1rem;
  width: 260px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: 0 8px 24px var(--color-shadow);
  z-index: 200;
  padding: 1rem;
  transition: opacity var(--transition-fast), transform var(--transition-fast);
}

.settings-panel.hidden {
  opacity: 0;
  transform: translateY(-0.5rem);
  pointer-events: none;
}

.settings-panel-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.75rem;
  font-weight: 600;
  font-size: 0.9rem;
}

.settings-close {
  background: none;
  border: none;
  color: var(--color-text-muted);
  cursor: pointer;
  font-size: 0.9rem;
  padding: 0.15rem;
  border-radius: var(--radius-sm);
}

.settings-close:hover {
  color: var(--color-text);
  background: var(--color-hover-bg);
}

.settings-row {
  margin-bottom: 0.65rem;
}

.settings-row:last-child {
  margin-bottom: 0;
}

.settings-row label {
  display: flex;
  justify-content: space-between;
  font-size: 0.8rem;
  color: var(--color-text);
  margin-bottom: 0.2rem;
}

.settings-row label span {
  color: var(--color-text-muted);
  font-variant-numeric: tabular-nums;
}

.settings-row input[type="range"] {
  width: 100%;
  accent-color: var(--color-primary);
  height: 4px;
}

/* Theme selector */
.theme-options {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.35rem;
  margin-top: 0.3rem;
}

.theme-btn {
  padding: 0.35rem 0;
  font-size: 0.8rem;
  font-family: var(--font-sans);
  color: var(--color-text-muted);
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.theme-btn:hover {
  background: var(--color-hover-bg);
  color: var(--color-text);
}

.theme-btn.active {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}

/* ─── Print Styles ──────────────────────────────────────────────────────── */
@media print {
  .sidebar,
  .sidebar-backdrop,
  .topbar,
  .copy-btn,
  .toast-container,
  .sidebar-toggle,
  .settings-toggle,
  .settings-panel {
    display: none !important;
  }

  .main-wrapper {
    margin-left: 0 !important;
  }

  .content {
    max-width: 100%;
    padding: 0;
  }

  .content pre {
    border: 1px solid #000;
    background: #fff;
    page-break-inside: avoid;
  }

  .content pre code {
    color: #000;
  }

  .content a[href]::after {
    content: " (" attr(href) ")";
    font-size: 0.8em;
    color: #555;
  }

  .content a[href^="#"]::after,
  .content a.footnote-ref::after,
  .content a.footnote-backref::after {
    content: none;
  }

  .content img {
    max-width: 100% !important;
    page-break-inside: avoid;
  }

  /* KaTeX formulas readable in print */
  .katex { color: #000; }

  body {
    font-size: 12pt;
    color: #000;
    background: #fff;
  }
}