:root {
  --bg: #f6f7fb;
  --surface: #ffffff;
  --text: #1a1d26;
  --muted: #5c6478;
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --accent: #10b981;
  --border: #e5e7ef;
  --shadow: 0 10px 30px rgba(15, 23, 42, 0.08);
  --radius: 14px;
  --max: 1080px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: "Pretendard", "Apple SD Gothic Neo", "Noto Sans KR", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

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

.container { max-width: var(--max); margin: 0 auto; padding: 0 20px; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 64px;
  gap: 16px;
}
.logo {
  font-weight: 800;
  font-size: 1.15rem;
  color: var(--text);
  text-decoration: none;
}
.logo span { color: var(--primary); }
.nav { display: flex; gap: 18px; flex-wrap: wrap; }
.nav a { color: var(--muted); font-weight: 600; font-size: 0.95rem; text-decoration: none; }
.nav a:hover, .nav a.active { color: var(--primary); }

.hero {
  padding: 56px 0 40px;
}
.hero-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 28px;
  align-items: center;
}
.hero h1 {
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  line-height: 1.25;
  margin: 0 0 14px;
}
.hero p { color: var(--muted); font-size: 1.05rem; margin: 0 0 22px; }
.hero-actions { display: flex; gap: 12px; flex-wrap: wrap; }

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 18px;
  border-radius: 10px;
  font-weight: 700;
  border: none;
  cursor: pointer;
  text-decoration: none;
}
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); text-decoration: none; }
.btn-secondary { background: #eef2ff; color: var(--primary); }
.btn-secondary:hover { text-decoration: none; }

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 18px;
  margin: 28px 0 48px;
}
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
  box-shadow: var(--shadow);
}
.card h3 { margin: 0 0 8px; font-size: 1.08rem; }
.card p { margin: 0; color: var(--muted); font-size: 0.95rem; }

.section { padding: 24px 0 40px; }
.section h2 { margin: 0 0 16px; font-size: 1.45rem; }

.tool-panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow);
}
.tool-panel label {
  display: block;
  font-weight: 700;
  margin-bottom: 8px;
}
.tool-panel textarea,
.tool-panel input,
.tool-panel select {
  width: 100%;
  padding: 12px 14px;
  border: 1px solid var(--border);
  border-radius: 10px;
  font: inherit;
  margin-bottom: 14px;
}
.tool-panel textarea { min-height: 120px; resize: vertical; }

.result-box {
  margin-top: 18px;
  padding: 16px;
  border-radius: 10px;
  background: #f0fdf4;
  border: 1px solid #bbf7d0;
}
.result-box.warn { background: #fffbeb; border-color: #fde68a; }
.result-box.error { background: #fef2f2; border-color: #fecaca; }
.metric-row {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 10px;
}
.metric {
  flex: 1;
  min-width: 120px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px;
  text-align: center;
}
.metric strong { display: block; font-size: 1.4rem; color: var(--primary); }

.cta-banner {
  margin: 40px 0;
  padding: 28px;
  border-radius: var(--radius);
  background: linear-gradient(135deg, #1e3a8a, #2563eb);
  color: #fff;
}
.cta-banner p { margin: 0 0 14px; opacity: 0.95; }

.article {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  box-shadow: var(--shadow);
}
.article h1 { margin-top: 0; }
.article h2 { margin-top: 28px; }
.article ul { padding-left: 20px; }

.site-footer {
  margin-top: 48px;
  padding: 28px 0 40px;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.92rem;
}
.footer-links { display: flex; gap: 16px; flex-wrap: wrap; margin-bottom: 10px; }

.ad-slot {
  min-height: 90px;
  border: 1px dashed var(--border);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--muted);
  font-size: 0.85rem;
  margin: 20px 0;
  background: #fafafa;
}

@media (max-width: 768px) {
  .hero-grid { grid-template-columns: 1fr; }
  .nav { display: none; }
}