/* ============================================
   Global Styles
   ============================================ */

/* --- CSS Custom Properties (Theme Tokens) --- */
:root {
  --primary: #1677ff;
  --primary-hover: #4096ff;
  --primary-active: #0958d9;
  --primary-bg: #e6f4ff;
  --primary-border: #91caff;

  --text-primary: #1f1f1f;
  --text-secondary: #595959;
  --text-muted: #8c8c8c;
  --text-white: #ffffff;

  --bg-body: #f5f7fa;
  --bg-white: #ffffff;
  --bg-light: #fafafa;

  --border-color: #e8e8e8;
  --border-radius: 8px;
  --border-radius-lg: 12px;
  --border-radius-sm: 4px;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.12);

  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, sans-serif;
  --font-mono: "SF Mono", "Fira Code", "Fira Mono", "Roboto Mono", Consolas,
    "Courier New", monospace;

  --header-height: 64px;
  --sidebar-width: 260px;
  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s ease;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-height) + 16px);
}

body {
  margin: 0;
  padding: 0;
  font-family: var(--font-family);
  font-size: 16px;
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--bg-body);
}

/* --- Links --- */
a {
  color: var(--primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

/* --- Headings --- */
h1, h2, h3, h4, h5, h6 {
  margin-top: 0;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.35;
}

/* --- Code --- */
code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background-color: var(--primary-bg);
  color: var(--primary-active);
  padding: 2px 6px;
  border-radius: var(--border-radius-sm);
}

pre {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  background-color: #f6f8fa;
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  padding: 16px;
  overflow-x: auto;
  line-height: 1.5;
}

pre code {
  background: none;
  padding: 0;
  color: inherit;
}

/* --- Header (Navbar) Styles --- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1030;
  background-color: var(--bg-white);
  border-bottom: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  height: var(--header-height);
}

.site-header .navbar {
  min-height: var(--header-height);
  padding-top: 0;
  padding-bottom: 0;
}

.site-header .navbar-brand {
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--primary);
  display: flex;
  align-items: center;
  gap: 8px;
}

.site-header .navbar-brand:hover {
  color: var(--primary-hover);
}

.site-header .navbar-nav {
  gap: 6px;
}

.site-header .nav-link {
  font-weight: 500;
  color: var(--text-secondary);
  padding: 8px 16px;
  border-radius: var(--border-radius);
  transition: color var(--transition-fast), background-color var(--transition-fast);
}

.site-header .nav-link:hover {
  color: var(--primary);
  background-color: var(--primary-bg);
}

.site-header .nav-link.active {
  color: var(--primary);
  background-color: var(--primary-bg);
  font-weight: 600;
}

.site-header .navbar-toggler {
  border: 1px solid var(--border-color);
  padding: 4px 8px;
}

.site-header .navbar-toggler:focus {
  box-shadow: 0 0 0 3px rgba(22, 119, 255, 0.25);
}

/* --- Footer Styles --- */
.site-footer {
  background-color: var(--bg-white);
  border-top: 1px solid var(--border-color);
  padding: 24px 0;
  color: var(--text-muted);
  font-size: 0.875rem;
}

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

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

.site-footer .footer-links {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  justify-content: center;
}

/* --- Utility Classes --- */
.text-primary-custom {
  color: var(--primary);
}

.bg-primary-custom {
  background-color: var(--primary);
}

.bg-primary-light {
  background-color: var(--primary-bg);
}

.btn-primary-custom {
  background-color: var(--primary);
  border-color: var(--primary);
  color: var(--text-white);
  font-weight: 500;
  padding: 10px 24px;
  border-radius: var(--border-radius);
  transition: all var(--transition-fast);
}

.btn-primary-custom:hover {
  background-color: var(--primary-hover);
  border-color: var(--primary-hover);
  color: var(--text-white);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn-primary-custom:active {
  background-color: var(--primary-active);
  border-color: var(--primary-active);
  transform: translateY(0);
}

.btn-outline-primary-custom {
  background-color: transparent;
  border: 1px solid var(--primary);
  color: var(--primary);
  font-weight: 500;
  padding: 10px 24px;
  border-radius: var(--border-radius);
  transition: all var(--transition-fast);
}

.btn-outline-primary-custom:hover {
  background-color: var(--primary);
  color: var(--text-white);
}

/* --- Section Badge (HTML / CSS / JS tags) --- */
.section-badge {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.5px;
  text-transform: uppercase;
}

.section-badge-html {
  background-color: #fff1f0;
  color: #cf1322;
  border: 1px solid #ffa39e;
}

.section-badge-css {
  background-color: #f6ffed;
  color: #389e0d;
  border: 1px solid #b7eb8f;
}

.section-badge-js {
  background-color: #fffbe6;
  color: #d48806;
  border: 1px solid #ffe58f;
}

/* --- Page body offset for fixed header + sticky footer --- */
.page-body {
  padding-top: var(--header-height);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.page-body > .site-footer,
.page-body > #footer-placeholder {
  margin-top: auto;
}

/* --- Responsive Utilities --- */
@media (max-width: 991.98px) {
  :root {
    --sidebar-width: 0px;
  }

  .site-header .navbar-collapse {
    background-color: var(--bg-white);
    border-top: 1px solid var(--border-color);
    padding: 8px 0;
    margin-top: 8px;
  }
}

@media (max-width: 575.98px) {
  body {
    font-size: 15px;
  }
}