@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&family=Fira+Code:wght@400;500&display=swap');

/* ===================================================
   主题变量 — Light Theme (default)
=================================================== */
:root {
  --pk-bg-main: #ffffff;
  --pk-bg-sidebar: #f8fafc;
  --pk-bg-code: #f1f5f9;
  --pk-bg-hover: #eff6ff;
  --pk-bg-quote: #f0fdf4;
  --pk-bg-table-header: #f8fafc;
  --pk-bg-table-row-odd: #ffffff;
  --pk-bg-table-row-even: #f4f8ff;
  --pk-bg-table-hover: #e0eeff;

  --pk-text-main: #1e293b;
  --pk-text-muted: #64748b;
  --pk-text-heading: #0f172a;

  --pk-primary: #3b82f6;
  --pk-primary-hover: #2563eb;
  --pk-accent: #10b981;
  --pk-code-text: #be123c;

  --pk-border-light: #e2e8f0;
  --pk-border-focus: #bfdbfe;

  --pk-shadow-sm: 0 1px 3px 0 rgb(0 0 0 / 0.07);
  --pk-shadow-md: 0 4px 12px -1px rgb(0 0 0 / 0.12);

  --pk-code-bg: #1e1e1e;
  --pk-code-text-block: #d4d4d4;
  --pk-code-border: #333;
  --pk-scrollbar-thumb: #cbd5e1;

  --pk-radius-sm: 6px;
  --pk-radius-md: 10px;
  --pk-radius-lg: 16px;

  --pk-sidebar-width: 320px;
  --pk-transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);

  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'Fira Code', Consolas, Monaco, monospace;

  /* 主题切换按钮 */
  --pk-theme-btn-bg: #e2e8f0;
  --pk-theme-btn-fg: #475569;
}

/* ===================================================
   Dark Theme
=================================================== */
[data-theme="dark"] {
  --pk-bg-main: #0f172a;
  --pk-bg-sidebar: #1e293b;
  --pk-bg-code: #1e293b;
  --pk-bg-hover: #1e3a5f;
  --pk-bg-quote: #0d2218;
  --pk-bg-table-header: #1e293b;
  --pk-bg-table-row-odd: #0f172a;
  --pk-bg-table-row-even: #162032;
  --pk-bg-table-hover: #1e3a5f;

  --pk-text-main: #e2e8f0;
  --pk-text-muted: #94a3b8;
  --pk-text-heading: #f1f5f9;

  --pk-primary: #60a5fa;
  --pk-primary-hover: #93c5fd;
  --pk-accent: #34d399;
  --pk-code-text: #f87171;

  --pk-border-light: #334155;
  --pk-border-focus: #1e40af;

  --pk-shadow-sm: 0 1px 3px 0 rgb(0 0 0 / 0.4);
  --pk-shadow-md: 0 4px 16px -1px rgb(0 0 0 / 0.5);

  --pk-code-bg: #020617;
  --pk-code-text-block: #e2e8f0;
  --pk-code-border: #1e293b;
  --pk-scrollbar-thumb: #334155;

  --pk-theme-btn-bg: #334155;
  --pk-theme-btn-fg: #94a3b8;
}

/* ===================================================
   Reset & Base
=================================================== */
html {
  scroll-behavior: smooth;
}

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

body {
  margin: 0;
  padding: 0;
  font-family: var(--font-sans);
  color: var(--pk-text-main);
  background: var(--pk-bg-main);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  transition: background 0.3s ease, color 0.3s ease;
}

/* ===================================================
   Theme Toggle Button
=================================================== */
#theme-toggle {
  position: fixed;
  top: 16px;
  right: 20px;
  z-index: 200;
  width: 42px;
  height: 42px;
  border-radius: 50%;
  border: 1px solid var(--pk-border-light);
  background: var(--pk-theme-btn-bg);
  color: var(--pk-theme-btn-fg);
  cursor: pointer;
  font-size: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--pk-shadow-md);
  transition: var(--pk-transition);
  user-select: none;
}

#theme-toggle:hover {
  transform: scale(1.1) rotate(20deg);
  background: var(--pk-primary);
  color: #fff;
  border-color: var(--pk-primary);
}

/* ===================================================
   Layout
=================================================== */
.container {
  display: flex;
  min-height: 100vh;
  position: relative;
}

/* ===================================================
   Sidebar
=================================================== */
.sidebar {
  width: var(--pk-sidebar-width);
  background: var(--pk-bg-sidebar);
  border-right: 1px solid var(--pk-border-light);
  padding: 24px 0 24px 0;
  position: fixed;
  height: 100vh;
  overflow-y: auto;
  left: 0;
  top: 0;
  z-index: 50;
  box-shadow: var(--pk-shadow-sm);
  transition: background 0.3s ease, border-color 0.3s ease;
}

.sidebar::-webkit-scrollbar {
  width: 5px;
}

.sidebar::-webkit-scrollbar-thumb {
  background: var(--pk-scrollbar-thumb);
  border-radius: 4px;
}

/* ===================================================
   Sidebar Brand Header
=================================================== */
.sidebar-brand {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 20px 20px 18px;
  border-bottom: 1px solid var(--pk-border-light);
  margin-bottom: 8px;
  text-decoration: none;
}

.brand-logo {
  flex-shrink: 0;
  width: 42px;
  height: 42px;
  border-radius: var(--pk-radius-sm);
  background: linear-gradient(135deg, var(--pk-primary), var(--pk-accent));
  color: #fff;
  font-weight: 700;
  font-size: 1rem;
  display: flex;
  align-items: center;
  justify-content: center;
  letter-spacing: -0.02em;
  box-shadow: 0 2px 8px rgb(59 130 246 / 0.4);
}

.brand-name {
  font-size: 1rem;
  font-weight: 700;
  color: var(--pk-text-heading);
  letter-spacing: -0.01em;
  line-height: 1.2;
}

.brand-sub {
  font-size: 0.75rem;
  color: var(--pk-text-muted);
  margin-top: 2px;
  line-height: 1;
}

/* Sidebar TOC title */
.sidebar h2 {
  margin: 0 20px 16px;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--pk-text-muted);
  padding-bottom: 12px;
  border-bottom: 1px solid var(--pk-border-light);
}

/* TOC Items */
.sidebar .toc-item {
  padding: 7px 20px;
  cursor: pointer;
  border-radius: 0 var(--pk-radius-sm) var(--pk-radius-sm) 0;
  transition: var(--pk-transition);
  margin: 1px 10px 1px 0;
  display: flex;
  align-items: center;
  font-size: 0.92rem;
  color: var(--pk-text-muted);
  border-left: 2px solid transparent;
  line-height: 1.4;
}

.sidebar .toc-item:hover {
  background: var(--pk-bg-hover);
  color: var(--pk-primary);
  border-left-color: var(--pk-primary);
}

.sidebar .toc-item.active {
  background: var(--pk-bg-hover);
  color: var(--pk-primary);
  border-left-color: var(--pk-primary);
  font-weight: 600;
}

.sidebar .toc-item.level-1 {
  font-weight: 600;
  color: var(--pk-text-heading);
  font-size: 0.95rem;
  margin-top: 6px;
}

.sidebar .toc-item.level-2 {
  padding-left: 36px;
  font-size: 0.88rem;
}

.sidebar .toc-item.level-3 {
  padding-left: 52px;
  font-size: 0.81rem;
  color: var(--pk-text-muted);
}

/* ===================================================
   Main Content
=================================================== */
.main-content {
  margin-left: var(--pk-sidebar-width);
  flex: 1;
  padding: 56px 72px 48px;
  max-width: 980px;
  width: 100%;
  animation: fadeUp 0.5s ease-out;
}

@keyframes fadeUp {
  from {
    opacity: 0;
    transform: translateY(16px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ===================================================
   Typography
=================================================== */
h1,
h2,
h3,
h4,
h5,
h6 {
  color: var(--pk-text-heading);
  font-weight: 700;
  line-height: 1.3;
  margin-top: 2.5rem;
  margin-bottom: .8rem;
  letter-spacing: -0.02em;
}

h1 {
  font-size: 2.6rem;
  position: relative;
  padding-bottom: 16px;
  margin-bottom: 1.5rem;
}

h1::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 56px;
  height: 4px;
  background: linear-gradient(90deg, var(--pk-primary), var(--pk-accent));
  border-radius: 2px;
}

h2 {
  font-size: 1.9rem;
  border-bottom: 1px solid var(--pk-border-light);
  padding-bottom: 10px;
  margin-top: 3rem;
}

h3 {
  font-size: 1.45rem;
}

h4 {
  font-size: 1.2rem;
  color: var(--pk-primary);
}

p {
  margin-bottom: 1.2rem;
  font-size: 1.02rem;
}

strong,
b {
  font-weight: 600;
  color: var(--pk-text-heading);
}

a {
  color: var(--pk-primary);
  text-decoration: none;
  font-weight: 500;
  transition: var(--pk-transition);
  border-bottom: 1px dashed transparent;
}

a:hover {
  color: var(--pk-primary-hover);
  border-bottom-color: var(--pk-primary-hover);
}

/* ===================================================
   Blockquotes
=================================================== */
blockquote {
  margin: 1.8rem 0;
  padding: 1.1rem 1.5rem;
  border-left: 4px solid var(--pk-accent);
  background: var(--pk-bg-quote);
  border-radius: 0 var(--pk-radius-md) var(--pk-radius-md) 0;
  font-style: italic;
  box-shadow: var(--pk-shadow-sm);
}

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

/* ===================================================
   Code
=================================================== */
code {
  font-family: var(--font-mono);
  background: var(--pk-bg-code);
  color: var(--pk-code-text);
  padding: 0.18em 0.45em;
  border-radius: var(--pk-radius-sm);
  font-size: 0.875em;
  border: 1px solid var(--pk-border-light);
}

pre {
  background: var(--pk-code-bg);
  border: 1px solid var(--pk-code-border);
  border-radius: var(--pk-radius-md);
  padding: 1.25rem;
  overflow-x: auto;
  margin: 1.5rem 0;
  box-shadow: var(--pk-shadow-md);
}

pre::-webkit-scrollbar {
  height: 6px;
}

pre::-webkit-scrollbar-thumb {
  background: #555;
  border-radius: 3px;
}

pre code {
  color: var(--pk-code-text-block);
  background: none;
  border: none;
  padding: 0;
  font-size: 0.9em;
  line-height: 1.6;
}

/* ===================================================
   Tables — 隔行渐变 (Zebra Stripes with Gradient)
=================================================== */
table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  margin: 1.75rem 0;
  border-radius: var(--pk-radius-md);
  overflow: hidden;
  box-shadow: var(--pk-shadow-sm);
  border: 1px solid var(--pk-border-light);
  font-size: 0.97rem;
}

th {
  padding: 13px 16px;
  text-align: left;
  background: var(--pk-bg-table-header);
  color: var(--pk-text-heading);
  font-weight: 600;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  border-bottom: 2px solid var(--pk-border-light);
}

td {
  padding: 11px 16px;
  border-bottom: 1px solid var(--pk-border-light);
  vertical-align: top;
  transition: background 0.15s ease;
}

/* 隔行渐变 */
tr:nth-child(odd) td {
  background: var(--pk-bg-table-row-odd);
}

tr:nth-child(even) td {
  background: linear-gradient(90deg,
      var(--pk-bg-table-row-even),
      color-mix(in srgb, var(--pk-bg-table-row-even) 60%, var(--pk-bg-main)));
}

tr:last-child td {
  border-bottom: none;
}

/* hover 高亮 */
tbody tr:hover td {
  background: var(--pk-bg-table-hover) !important;
}

/* ===================================================
   Lists
=================================================== */
ul,
ol {
  padding-left: 1.6rem;
  margin-bottom: 1.4rem;
}

li {
  margin-bottom: 0.45rem;
  font-size: 1.02rem;
}

li::marker {
  color: var(--pk-primary);
}

/* ===================================================
   Site Footer
=================================================== */
.site-footer {
  margin-top: 64px;
  padding: 28px 0 8px;
  border-top: 1px solid var(--pk-border-light);
}

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 4px;
  font-size: 0.88rem;
  color: var(--pk-text-muted);
}

.footer-brand {
  font-weight: 700;
  background: linear-gradient(90deg, var(--pk-primary), var(--pk-accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  font-size: 0.95rem;
}

.footer-sep {
  color: var(--pk-border-light);
  font-size: 1.1rem;
  line-height: 1;
}

/* ===================================================
   Horizontal Rule
=================================================== */
hr {
  border: none;
  height: 1px;
  background: linear-gradient(to right, transparent, var(--pk-border-light), transparent);
  margin: 2.5rem 0;
}

/* ===================================================
   Scrollbar (main area)
=================================================== */
body::-webkit-scrollbar {
  width: 8px;
}

body::-webkit-scrollbar-thumb {
  background: var(--pk-scrollbar-thumb);
  border-radius: 4px;
}

/* ===================================================
   Responsive
=================================================== */
@media (max-width: 1024px) {
  .main-content {
    padding: 32px 40px 64px;
  }
}

@media (max-width: 768px) {
  .container {
    flex-direction: column;
  }

  .sidebar {
    position: static;
    width: 100%;
    height: auto;
    max-height: 360px;
    border-right: none;
    border-bottom: 1px solid var(--pk-border-light);
    box-shadow: none;
  }

  .main-content {
    margin-left: 0;
    padding: 24px 20px 48px;
  }

  h1 {
    font-size: 2rem;
  }

  h2 {
    font-size: 1.5rem;
  }

  #theme-toggle {
    top: 10px;
    right: 12px;
  }
}