:root {
  --theme-max-width: 1400px;
  --theme-font: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --theme-bg: #ffffff;
  --theme-text: #1d2327;
  --theme-text-light: #646970;
  --theme-border: #dcdcde;
  --theme-primary: #1a73e8;
  --theme-header-bg: #ffffff;
  --theme-footer-bg: #f5f7fa;
}

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

body {
  margin: 0;
  font-family: var(--theme-font);
  color: var(--theme-text);
  background: var(--theme-bg);
  line-height: 1.6;
}

a {
  color: var(--theme-primary);
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
}

img {
  max-width: 100%;
  height: auto;
}

.site-header {
  background: var(--theme-header-bg);
  border-bottom: 1px solid var(--theme-border);
  position: sticky;
  top: 0;
  z-index: 100;
}
.header-inner {
  max-width: var(--theme-max-width);
  margin: 0 auto;
  padding: 12px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.site-title {
  font-size: 22px;
  font-weight: 700;
  color: var(--theme-text);
}
.site-title:hover {
  text-decoration: none;
  color: var(--theme-primary);
}

.main-navigation ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 24px;
}
.main-navigation a {
  font-size: 14px;
  font-weight: 500;
  color: var(--theme-text);
  padding: 4px 0;
  border-bottom: 2px solid transparent;
  transition: border-color 0.2s;
}
.main-navigation a:hover {
  text-decoration: none;
  border-bottom-color: var(--theme-primary);
}
.menu-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.site-main {
  max-width: var(--theme-max-width);
  margin: 0 auto;
  padding: 24px;
  min-height: 60vh;
}

.site-footer {
  background: var(--theme-footer-bg);
  border-top: 1px solid var(--theme-border);
  margin-top: 48px;
}
.footer-inner {
  max-width: var(--theme-max-width);
  margin: 0 auto;
  padding: 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 13px;
  color: var(--theme-text-light);
}
.footer-navigation ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 16px;
}
.footer-navigation a {
  color: var(--theme-text-light);
}
.footer-navigation a:hover {
  color: var(--theme-text);
}

@media (max-width: 768px) {
  .main-navigation ul {
    display: none;
    flex-direction: column;
    gap: 8px;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--theme-header-bg);
    border-bottom: 1px solid var(--theme-border);
    padding: 12px 24px;
  }
  .main-navigation ul.active {
    display: flex;
  }
  .menu-toggle {
    display: block;
  }
  .header-inner {
    flex-wrap: wrap;
  }
  .footer-inner {
    flex-direction: column;
    gap: 8px;
    text-align: center;
  }
}