/* ── CSS Variables ── */
:root {
  --color-bg: #f5f7fa;
  --color-surface: #ffffff;
  --color-border: #e4e8ec;
  --color-text: #2c3e50;
  --color-text-muted: #7f8c8d;
  --color-primary: #2b6777;
  --color-primary-light: #c8e8ee;
  --color-accent: #c8956c;
  --color-accent-light: #f9f3ee;
  --color-danger: #922b21;
  --color-success: #1e8449;
  --color-warning: #d4ac0d;
  --color-info: #2e86c1;
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
  --font-base: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans KR', sans-serif;
  --font-mono: 'SFMono-Regular', Consolas, monospace;
  --max-width: 960px;
}

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

body {
  font-family: var(--font-base);
  font-size: 14px;
  line-height: 1.6;
  color: var(--color-text);
  background: var(--color-bg);
  min-height: 100vh;
}

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

a:hover {
  text-decoration: underline;
}

/* ── Navbar ── */
.navbar {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-sm);
}

.nav-brand a {
  font-size: 18px;
  font-weight: 700;
  color: var(--color-primary);
  letter-spacing: -0.02em;
}

.nav-links {
  display: flex;
  gap: 24px;
}

.nav-links a {
  font-size: 14px;
  font-weight: 500;
  color: var(--color-text-muted);
  padding: 4px 0;
  border-bottom: 2px solid transparent;
  transition: color 0.15s, border-color 0.15s;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--color-primary);
  border-bottom-color: var(--color-accent);
  text-decoration: none;
}

/* ── Container ── */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 32px 24px;
}

/* ── Footer ── */
.footer {
  text-align: center;
  padding: 24px;
  color: var(--color-text-muted);
  font-size: 12px;
  border-top: 1px solid var(--color-border);
}

/* ── Page Title ── */
.page-title {
  font-size: 24px;
  font-weight: 700;
  margin-bottom: 24px;
  color: var(--color-text);
}

/* ── Grid ── */
.grid {
  display: grid;
  gap: 24px;
  margin-bottom: 24px;
}

.grid-2 {
  grid-template-columns: repeat(2, 1fr);
}

@media (max-width: 720px) {
  .grid-2 {
    grid-template-columns: 1fr;
  }
}

/* ── Responsive base ── */
@media (max-width: 720px) {
  .navbar {
    padding: 0 16px;
  }

  .container {
    padding: 20px 16px;
  }

  .page-title {
    font-size: 20px;
  }
}