:root {
  --color-bg-primary: #fdfaf6;
  --color-bg-secondary: #ffffff;
  --color-bg-card: #ffffff;
  --color-bg-code: #f7f2ea;
  --color-border: rgba(0,0,0,0.06);
  --color-text-primary: #3d3128;
  --color-text-secondary: #6b5c50;
  --color-text-tertiary: #9a8b7f;
  --color-link: #b88a62;
  --color-link-hover: #d4a574;
  --color-primary: #d4a574;
  --color-surface: #ffffff;
  --color-tip-bg: #fef9f3;
  --color-tip-border: #f0e4d7;
  --color-warning-bg: #fff9e6;
  --color-warning-border: #f5c842;
  --color-error-bg: #fff0f0;
  --color-error-border: #f08080;
  --font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", "Noto Sans SC", sans-serif;
}

[data-theme="dark"] {
  --color-bg-primary: #1a1816;
  --color-bg-secondary: #252220;
  --color-bg-card: #252220;
  --color-bg-code: #2a2725;
  --color-border: rgba(255,255,255,0.08);
  --color-text-primary: #f0ebe6;
  --color-text-secondary: #c4bdb5;
  --color-text-tertiary: #8a827a;
  --color-link: #d4a574;
  --color-link-hover: #e8c49a;
  --color-primary: #d4a574;
  --color-surface: #252220;
  --color-tip-bg: #2a2520;
  --color-tip-border: #4a4035;
  --color-warning-bg: #2a2520;
  --color-warning-border: #5a4a30;
  --color-error-bg: #2a2020;
  --color-error-border: #5a3030;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family);
  background: var(--color-bg-primary);
  color: var(--color-text-primary);
  line-height: 1.65;
  transition: background 0.2s ease, color 0.2s ease;
  min-height: 100vh;
}

a {
  color: var(--color-link);
  text-decoration: none;
  transition: color 0.2s ease;
}

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

button {
  font-family: inherit;
  cursor: pointer;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: 0.75rem;
  padding: 1.5rem;
  box-shadow: 0 1px 3px rgba(0,0,0,0.04);
}

.card:hover {
  box-shadow: 0 4px 12px rgba(0,0,0,0.08);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.6rem 1.2rem;
  border-radius: 0.5rem;
  font-size: 0.9rem;
  font-weight: 500;
  border: 1px solid var(--color-border);
  background: var(--color-surface);
  color: var(--color-text-primary);
  transition: all 0.2s ease;
}

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

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

.btn-primary:hover {
  opacity: 0.9;
}

input, textarea, select {
  font-family: inherit;
  font-size: 1rem;
  padding: 0.6rem 1rem;
  border: 1px solid var(--color-border);
  border-radius: 0.5rem;
  background: var(--color-surface);
  color: var(--color-text-primary);
  transition: border-color 0.2s ease;
}

input:focus, textarea:focus, select:focus {
  outline: none;
  border-color: var(--color-primary);
}

input::placeholder, textarea::placeholder {
  color: var(--color-text-tertiary);
}

.theme-toggle {
  background: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: 2rem;
  padding: 0.5rem 1rem;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.8rem;
  color: var(--color-text-secondary);
  transition: all 0.2s ease;
}

.theme-toggle:hover {
  background: var(--color-bg-card);
  border-color: var(--color-primary);
}

code {
  background: var(--color-bg-code);
  padding: 0.15rem 0.4rem;
  border-radius: 0.25rem;
  font-size: 0.9em;
  color: var(--color-link);
  border: 1px solid var(--color-border);
}

pre {
  background: var(--color-bg-code);
  border-radius: 0.5rem;
  padding: 1rem;
  overflow-x: auto;
  border: 1px solid var(--color-border);
}

pre code {
  background: none;
  padding: 0;
  font-size: 0.9rem;
  border: none;
}

.nav-bar {
  background: var(--color-bg-secondary);
  border-bottom: 1px solid var(--color-border);
  padding: 1rem 0;
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.nav-bar .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-weight: 600;
  font-size: 1.25rem;
  color: var(--color-text-primary);
}

.nav-links {
  display: flex;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.nav-links a {
  color: var(--color-text-secondary);
  font-weight: 500;
  padding-bottom: 0.2rem;
  border-bottom: 2px solid transparent;
  transition: all 0.2s ease;
}

.nav-links a:hover {
  color: var(--color-link);
  border-bottom-color: var(--color-link);
}

.page-header {
  text-align: center;
  padding: 3rem 0;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: 2rem;
}

.page-title {
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-text-primary);
  margin-bottom: 0.5rem;
  letter-spacing: -0.02em;
}

.page-subtitle {
  color: var(--color-text-secondary);
  font-size: 1rem;
}

.section-title {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: 1.5rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--color-border);
}

.grid {
  display: grid;
  gap: 1.5rem;
}

.grid-2 {
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.grid-3 {
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
}

footer {
  border-top: 1px solid var(--color-border);
  padding: 2rem 0;
  margin-top: 3rem;
  color: var(--color-text-tertiary);
  font-size: 0.85rem;
}

footer .container {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}

.footer-links {
  display: flex;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.footer-links a {
  color: var(--color-text-tertiary);
}

.footer-links a:hover {
  color: var(--color-link);
}

@media (max-width: 768px) {
  .nav-bar .container {
    flex-direction: column;
    align-items: flex-start;
  }

  .nav-links {
    width: 100%;
    justify-content: flex-start;
  }

  .page-header {
    padding: 2rem 0;
  }

  .page-title {
    font-size: 1.75rem;
  }
}