:root {
  --bg: #f6f7fb;
  --panel: #ffffff;
  --text: #1e232b;
  --muted: #5b6472;
  --accent: #3a63f1;
  --accent-soft: rgba(58, 99, 241, 0.12);
  --accent-strong: #2746c2;
  --border: #e3e7ef;
  --code-bg: #f0f2f6;
  --shadow: 0 6px 20px rgba(16, 24, 40, 0.08);
  --nav-bg: rgba(255, 255, 255, 0.9);
}

:root[data-theme="dark"] {
  --bg: #0f1218;
  --panel: #141922;
  --text: #e6e9ef;
  --muted: #a7b0c0;
  --accent: #7aa2ff;
  --accent-soft: rgba(122, 162, 255, 0.18);
  --accent-strong: #5a86ff;
  --border: #232b3a;
  --code-bg: #1a2130;
  --shadow: 0 10px 28px rgba(0, 0, 0, 0.45);
  --nav-bg: rgba(20, 25, 34, 0.92);
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: "Inter", "Segoe UI", system-ui, -apple-system, sans-serif;
}

body,
.sidebar,
.markdown-section,
.site-header,
.site-footer,
.theme-toggle {
  transition:
    background-color 200ms ease,
    color 200ms ease,
    border-color 200ms ease,
    box-shadow 200ms ease,
    transform 200ms ease;
}

.app-nav {
  position: sticky;
  top: 0;
  background: var(--nav-bg);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  padding: 10px 24px;
  z-index: 10;
}

.app-nav a {
  color: var(--text);
  font-weight: 600;
}

.theme-toggle {
  position: fixed;
  right: 20px;
  bottom: 20px;
  padding: 8px 14px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: linear-gradient(135deg, var(--accent), var(--accent-strong));
  color: #ffffff;
  font-size: 12px;
  cursor: pointer;
  box-shadow: var(--shadow);
  z-index: 9999;
}

.theme-toggle:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 26px rgba(58, 99, 241, 0.25);
}

.sidebar {
  background: var(--panel);
  border-right: 1px solid var(--border);
  box-shadow: var(--shadow);
}

.sidebar ul li a {
  color: var(--text);
}

.sidebar ul li.active > a {
  color: var(--accent);
  font-weight: 600;
}

.sidebar ul li a:hover {
  color: var(--accent);
}

.content {
  background: transparent;
  box-shadow: none;
  border: none;
  padding: 0;
  margin: 0;
}

.markdown-section {
  color: var(--text);
  background: var(--panel);
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 24px;
  margin: 24px;
  animation: fadeUp 380ms ease both;
}

.markdown-section h1,
.markdown-section h2,
.markdown-section h3,
.markdown-section h4 {
  color: var(--text);
  letter-spacing: -0.02em;
}

.markdown-section h1 {
  background: linear-gradient(135deg, var(--accent), var(--accent-strong));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.markdown-section p,
.markdown-section li {
  color: var(--muted);
}

.markdown-section strong {
  color: var(--text);
}

.markdown-section code {
  background: var(--code-bg);
  color: var(--text);
  border-radius: 6px;
  padding: 2px 6px;
}

.markdown-section pre code {
  display: block;
  padding: 16px;
  background: var(--code-bg);
  border-radius: 10px;
}

.markdown-section table {
  border-collapse: collapse;
  width: 100%;
  background: var(--panel);
  border: 1px solid var(--border);
}

.markdown-section table th,
.markdown-section table td {
  border: 1px solid var(--border);
  padding: 10px 12px;
}

.markdown-section table th {
  background: var(--code-bg);
  color: var(--text);
  text-align: left;
}

.markdown-section a {
  color: var(--accent);
}

.markdown-section a:hover {
  color: var(--accent-strong);
}

.markdown-section blockquote {
  margin: 16px 0;
  padding: 12px 16px;
  border-left: 3px solid var(--accent);
  background: var(--accent-soft);
  color: var(--text);
  border-radius: 10px;
}

.site-header {
  margin: 24px 24px 0;
  padding: 16px 20px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: linear-gradient(135deg, var(--panel), var(--accent-soft));
  color: var(--text);
  box-shadow: var(--shadow);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  animation: fadeUp 320ms ease both;
}

.site-brand {
  display: grid;
  gap: 2px;
}

.site-links {
  display: flex;
  gap: 10px;
  align-items: center;
}

.site-link {
  display: inline-flex;
  align-items: center;
  padding: 8px 12px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--panel);
  color: var(--text);
  font-weight: 600;
}

.site-link:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.site-title {
  font-size: 18px;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.site-title::after {
  content: "";
  display: inline-block;
  width: 10px;
  height: 10px;
  margin-left: 10px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 6px var(--accent-soft);
  vertical-align: middle;
}

.site-tagline {
  color: var(--muted);
  font-size: 13px;
}

.site-footer {
  margin: 24px 0 0;
  padding: 14px 18px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--panel);
  color: var(--muted);
  text-align: center;
  box-shadow: var(--shadow);
  animation: fadeUp 420ms ease both;
  width: 100%;
  box-sizing: border-box;
}

@keyframes fadeUp {
  from {
    opacity: 0;
    transform: translateY(8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (prefers-reduced-motion: reduce) {
  .markdown-section,
  .site-header,
  .site-footer {
    animation: none;
  }

  body,
  .sidebar,
  .markdown-section,
  .site-header,
  .site-footer,
  .theme-toggle {
    transition: none;
  }
}

@media (max-width: 960px) {
  .markdown-section {
    margin: 16px;
    padding: 18px;
  }

  .site-header {
    margin: 16px 16px 0;
    flex-direction: column;
    align-items: flex-start;
  }

  .site-footer {
    margin: 16px 0 0;
  }
}