/* Shared site header + nav CTA buttons — matches index (styles.css) */

:root {
  --color-primary: #2196f3;
  --color-primary-dark: #1976d2;
  --color-primary-soft: rgba(33, 150, 243, 0.12);
  --color-text: #1a1d21;
  --color-text-muted: #5c6370;
  --color-border: #e8ecf1;
  --color-bg: #fafbfc;
  --font-sans: "Noto Sans SC", "DM Sans", system-ui, -apple-system, sans-serif;
  --shadow-sm: 0 1px 2px rgba(26, 29, 33, 0.06);
  --shadow-md: 0 8px 24px rgba(26, 29, 33, 0.08);
  --header-h: 64px;
  --ease: cubic-bezier(0.4, 0, 0.2, 1);
}

.site-header .container {
  width: 100%;
  max-width: 1120px;
  margin: 0 auto;
  padding-left: 8px;
  padding-right: 20px;
}

/* Deep-linked headings/cards clear the sticky header */
main [id] {
  scroll-margin-top: calc(var(--header-h) + 12px);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(250, 251, 252, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: var(--header-h);
  gap: 16px;
}

.logo {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  line-height: 1;
}

.logo-img {
  display: block;
  width: auto;
  height: 32px;
  object-fit: contain;
}

.logo-slogan {
  display: inline-flex;
  align-items: center;
  padding-left: 12px;
  border-left: 1px solid rgba(92, 99, 112, 0.22);
  font-weight: 700;
  font-size: 0.95rem;
  letter-spacing: -0.01em;
  color: var(--color-primary-dark);
  white-space: nowrap;
}

.logo:hover {
  opacity: 0.92;
  text-decoration: none;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: 0;
  border: none;
  background: transparent;
  cursor: pointer;
  border-radius: 8px;
}

.nav-toggle:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.nav-toggle-bar {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-text);
  margin: 0 auto;
  transition: transform 0.25s var(--ease), opacity 0.2s;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

.nav {
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 16px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-list a {
  color: var(--color-text);
  font-weight: 500;
  font-size: 0.9375rem;
  text-decoration: none;
}

.nav-list a:hover,
.nav-list a.is-active {
  color: var(--color-primary);
  text-decoration: none;
}

.nav-cta {
  flex-shrink: 0;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: inherit;
  font-weight: 600;
  font-size: 0.9375rem;
  line-height: 1.25;
  padding: 10px 20px;
  border-radius: 10px;
  border: 2px solid transparent;
  cursor: pointer;
  text-decoration: none;
  transition: background 0.2s var(--ease), color 0.2s var(--ease), border-color 0.2s var(--ease), box-shadow 0.2s var(--ease);
}

.btn:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.btn-sm {
  padding: 8px 16px;
  font-size: 0.875rem;
}

.btn-lg {
  padding: 14px 28px;
  font-size: 1rem;
}

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

.btn-primary:hover {
  background: var(--color-primary-dark);
  border-color: var(--color-primary-dark);
  color: #fff;
  text-decoration: none;
  box-shadow: var(--shadow-md);
}

.btn-ghost {
  background: transparent;
  color: var(--color-text);
  border-color: var(--color-border);
}

.btn-ghost:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  text-decoration: none;
}

@media (max-width: 768px) {
  .logo-img {
    height: 28px;
  }

  .logo {
    gap: 10px;
  }

  .logo-slogan {
    padding-left: 10px;
    font-size: 0.875rem;
    letter-spacing: 0;
  }

  .nav-toggle {
    display: flex;
  }

  .nav {
    position: fixed;
    top: var(--header-h);
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--color-bg);
    flex-direction: column;
    align-items: stretch;
    padding: 24px 20px 32px;
    gap: 24px;
    transform: translateX(100%);
    visibility: hidden;
    transition: transform 0.3s var(--ease), visibility 0.3s;
  }

  .nav.is-open {
    transform: translateX(0);
    visibility: visible;
  }

  .nav-list {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
  }

  .nav-list a {
    display: block;
    padding: 12px 0;
    font-size: 1.125rem;
  }

  .nav-cta {
    width: 100%;
    text-align: center;
  }
}

@media (prefers-reduced-motion: reduce) {
  .nav-toggle-bar,
  .nav {
    transition: none;
  }
}