:root {
  --bg: #f4f8fb;
  --card: #ffffff;
  --border: #e5e7eb;
  --text: #0f172a;
  --muted: #4b5563;
  --sky: #0284c7;
  --sky-soft: #e0f2fe;
  --emerald: #059669;
  --indigo: #4f46e5;
  --amber: #f59e0b;
  --shadow: 0 10px 30px rgba(15, 23, 42, 0.07);
}

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

body.core-page {
  margin: 0;
  min-height: 100vh;
  font-family: 'Pretendard', 'Noto Sans KR', system-ui, -apple-system, sans-serif;
  background:
    radial-gradient(circle at 20% 20%, rgba(2,132,199,0.08), transparent 30%),
    radial-gradient(circle at 80% 0%, rgba(79,70,229,0.09), transparent 35%),
    linear-gradient(180deg, #f8fbff 0%, #ffffff 100%);
  color: var(--text);
}

.core-inner {
  max-width: 1100px;
  margin: 0 auto;
  width: 100%;
  padding: 0 20px;
}

.core-content {
  max-width: 1100px;
  margin: 0 auto;
  padding: 24px 20px 60px;
}

/* Navigation */
.core-nav {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(10px);
  background: rgba(255, 255, 255, 0.85);
  border-bottom: 1px solid rgba(229, 231, 235, 0.7);
}
.core-nav .core-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 0;
}
.core-brand {
  display: flex;
  align-items: center;
  gap: 12px;
}
.core-brand-mark {
  height: 42px;
  width: 42px;
  border-radius: 12px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, var(--sky), #22c55e);
  color: #fff;
  font-weight: 700;
  box-shadow: var(--shadow);
}
.core-brand-domain {
  margin: 0;
  font-size: 12px;
  color: #6b7280;
}
.core-brand-title {
  margin: 2px 0 0 0;
  font-size: 18px;
  font-weight: 700;
}

.core-nav-links {
  display: none;
  align-items: center;
  gap: 18px;
  font-weight: 600;
  font-size: 14px;
}
.core-nav-links a {
  color: var(--text);
  text-decoration: none;
}
.core-nav-links a:hover {
  color: var(--sky);
}
.core-nav-links a.core-highlight {
  color: var(--sky);
}
.core-nav-links a.core-muted {
  color: #6b7280;
}

.core-nav-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border);
  padding: 8px 12px;
  border-radius: 10px;
  background: #fff;
  color: #475569;
  cursor: pointer;
}

.core-nav-mobile {
  display: none;
  flex-direction: column;
  padding: 0 20px 16px;
  gap: 10px;
  background: rgba(255, 255, 255, 0.95);
  border-top: 1px solid var(--border);
}
.core-nav-mobile a {
  font-weight: 600;
  text-decoration: none;
  color: var(--text);
}
.core-nav-mobile a:hover {
  color: var(--sky);
}

@media (min-width: 768px) {
  .core-nav-links { display: flex; }
  .core-nav-toggle { display: none; }
  .core-nav-mobile { display: none !important; }
}

.core-nav-links.open {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 14px 20px;
}
.core-nav-mobile.open {
  display: flex;
}

/* Footer */
.core-footer {
  border-top: 1px solid var(--border);
  background: rgba(255,255,255,0.9);
}
.core-footer-inner {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 16px 0;
  color: #6b7280;
  font-size: 14px;
}
.core-footer-links {
  display: flex;
  gap: 16px;
}
.core-footer a {
  color: inherit;
  text-decoration: none;
}
.core-footer a:hover {
  color: var(--sky);
}
@media (min-width: 768px) {
  .core-footer-inner {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
  }
}

/* Flash messages */
.core-flash-list {
  margin: 12px 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.core-flash {
  padding: 10px 14px;
  border-radius: 12px;
  font-size: 14px;
  border: 1px solid var(--border);
  background: #fff;
  box-shadow: 0 8px 20px rgba(15, 23, 42, 0.04);
}
.core-flash-info { border-color: #e0f2fe; background: #f8fbff; color: #0f172a; }
.core-flash-success { border-color: #d1fae5; background: #ecfdf3; color: #065f46; }
.core-flash-warning { border-color: #fef3c7; background: #fffbeb; color: #92400e; }
.core-flash-error { border-color: #fee2e2; background: #fef2f2; color: #991b1b; }

.core-form {
  display: grid;
  gap: 12px;
}
.core-form input,
.core-form textarea,
.core-form select {
  width: 100%;
  padding: 16px 18px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: #fff;
  font-size: 14px;
}
label {
  font-weight: 700;
  font-size: 14px;
  color: var(--text);
}
button,
input[type=submit] {
  font-family: inherit;
}