/* =========================
   RESET & BASE
========================= */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --page-padding: 20px;
  --max-width: 1200px;
}

html {
  font-size: 16px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI",
               Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.7;
  color: #1f2937;
  background-color: #f9fafb;
}

/* =========================
   SHARED INNER WRAPPER
========================= */
.site-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--page-padding);
}

/* =========================
   HEADER (STICKY)
========================= */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: #ffffff;
  border-bottom: 1px solid #e5e7eb;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 20px;
}

/* LOGO */
.logo a {
  font-size: 1.25rem;
  font-weight: 700;
  color: #111827;
  text-decoration: none;
}

/* =========================
   MENU
========================= */
.main-nav {
  display: flex;
  gap: 24px;
}

.main-nav a {
  font-size: 0.95rem;
  font-weight: 500;
  color: #374151;
  text-decoration: none;
  position: relative;
}

.main-nav a:hover {
  color: #2563eb;
}

/* underline hover */
.main-nav a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -4px;
  width: 0;
  height: 2px;
  background: #2563eb;
  transition: width 0.25s ease;
}

.main-nav a:hover::after {
  width: 100%;
}

/* =========================
   BREADCRUMB
========================= */
.breadcrumb {
  margin-top: 12px;
  font-size: 0.875rem;
  color: #6b7280;
}

.breadcrumb a {
  color: #6b7280;
  text-decoration: none;
}

.breadcrumb a:hover {
  color: #2563eb;
  text-decoration: underline;
}

.breadcrumb span {
  margin: 0 6px;
}

/* =========================
   CONTENT
========================= */
main.content {
  background: #ffffff;
  margin: 32px 0;
  padding: 32px;

  border-radius: 12px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.04);
}

/* =========================
   TYPOGRAPHY
========================= */
h1, h2, h3, h4 {
  color: #111827;
  line-height: 1.3;
  margin-bottom: 16px;
}

h1 {
  font-size: 2rem;
}

h2 {
  font-size: 1.5rem;
  margin-top: 40px;
}

p {
  margin-bottom: 16px;
  font-size: 1rem;
}

ul, ol {
  margin: 16px 0 16px 20px;
}

li {
  margin-bottom: 8px;
}

/* =========================
   IMAGES
========================= */
img {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
  margin: 16px 0;
}

/* =========================
   FOOTER
========================= */
.site-footer {
  background: #ffffff;
  border-top: 1px solid #e5e7eb;
  margin-top: 48px;
}

.footer-inner {
  padding: 24px 0;
  text-align: center;
  font-size: 0.875rem;
  color: #6b7280;
}

/* =========================
   MOBILE OPTIMIZATION
========================= */
@media (max-width: 768px) {

  .header-inner {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }

  .main-nav {
    flex-wrap: wrap;
    gap: 16px;
  }

  .breadcrumb {
    font-size: 0.8rem;
    margin-top: 8px;
  }

  main.content {
    margin: 16px 0;
    padding: 20px;
    border-radius: 0;
    box-shadow: none;
  }
}