:root {
  --primary-color: #2563eb;
  --secondary-color: #64748b;
  --success-color: #10b981;
  --error-color: #ef4444;
  --bg-color: #f8fafc;
  --card-bg: #ffffff;
  --text-main: #1e293b;
  --text-muted: #64748b;
  --accent-color: #3b82f6;
  --border-radius: 12px;
  --container-width: 1200px;
  --header-height: 72px;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-main);
  line-height: 1.6;
  padding-top: var(--header-height);
}

.container {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* Navbar Styles */
.navbar {
  height: var(--header-height);
  background: white;
  border-bottom: 1px solid #e2e8f0;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
}

.navbar .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
}

.logo {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--primary-color);
  letter-spacing: -0.5px;
}

.logo span {
  color: var(--text-main);
  font-weight: 600;
  margin-left: 2px;
}

nav ul {
  display: flex;
  list-style: none;
  gap: 32px;
}

nav ul a {
  text-decoration: none;
  color: var(--text-muted);
  font-weight: 500;
  transition: color 0.2s;
}

nav ul a.active, nav ul a:hover {
  color: var(--primary-color);
}

.auth-buttons {
  display: flex;
  gap: 12px;
}

/* Button Styles */
button {
  cursor: pointer;
  border: none;
  border-radius: 8px;
  font-family: inherit;
  transition: all 0.2s;
}

.btn-primary {
  background: var(--primary-color);
  color: white;
  padding: 8px 20px;
  font-weight: 600;
}

.btn-primary:hover {
  background: #1d4ed8;
  transform: translateY(-1px);
}

.btn-text {
  background: transparent;
  color: var(--text-muted);
  padding: 8px 12px;
  font-weight: 500;
}

.btn-outline {
  border: 1px solid #e2e8f0;
  background: white;
  color: var(--text-main);
  padding: 8px 16px;
  font-size: 0.875rem;
  font-weight: 500;
}

.btn-outline:hover {
  background: #f1f5f9;
  border-color: #cbd5e1;
}

/* Hero Section */
.hero {
  background: linear-gradient(135deg, #eff6ff 0%, #dbeafe 100%);
  padding: 80px 0;
  text-align: center;
}

.hero h1 {
  font-size: 2.75rem;
  font-weight: 800;
  margin-bottom: 16px;
  letter-spacing: -1px;
}

.hero h1 span {
  color: var(--primary-color);
}

.hero p {
  color: var(--text-muted);
  font-size: 1.125rem;
  margin-bottom: 40px;
}

.search-box {
  display: flex;
  max-width: 600px;
  margin: 0 auto;
  background: white;
  padding: 8px;
  border-radius: 16px;
  box-shadow: 0 10px 25px -5px rgba(37, 99, 235, 0.1);
}

.search-box input {
  flex: 1;
  border: none;
  padding: 12px 20px;
  font-size: 1rem;
  outline: none;
}

.btn-search {
  background: var(--primary-color);
  color: white;
  padding: 0 32px;
  font-weight: 600;
}

/* Filter Section */
.filters {
  padding: 32px 0;
  background: white;
  border-bottom: 1px solid #e2e8f0;
}

.filter-group {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.filter-tag {
  padding: 8px 16px;
  background: #f1f5f9;
  color: var(--text-muted);
  font-weight: 500;
  font-size: 0.9375rem;
}

.filter-tag.active {
  background: var(--primary-color);
  color: white;
}

/* Announcements Grid */
.announcements {
  padding: 60px 0;
}

.section-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 32px;
}

.section-header h2 {
  font-size: 1.5rem;
  font-weight: 700;
}

.section-header h2 span {
  color: var(--primary-color);
  font-weight: 500;
  font-size: 1.125rem;
  margin-left: 8px;
}

.announcement-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
  gap: 24px;
}

.announcement-card {
  background: var(--card-bg);
  border: 1px solid #e2e8f0;
  border-radius: var(--border-radius);
  padding: 24px;
  transition: all 0.3s ease;
  display: flex;
  flex-direction: column;
}

.announcement-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 20px -5px rgba(0, 0, 0, 0.1);
  border-color: var(--primary-color);
}

.card-header {
  display: flex;
  gap: 8px;
  margin-bottom: 16px;
}

.badge {
  padding: 4px 10px;
  border-radius: 4px;
  font-size: 0.75rem;
  font-weight: 700;
}

.badge.d-day {
  background: #fef2f2;
  color: #ef4444;
}

.badge.d-day.important {
  background: #ef4444;
  color: white;
}

.badge.category {
  background: #f1f5f9;
  color: var(--text-muted);
}

.card-title {
  font-size: 1.125rem;
  font-weight: 700;
  margin-bottom: 20px;
  line-height: 1.4;
  flex: 1;
}

.card-info {
  margin-bottom: 20px;
}

.info-item {
  display: flex;
  justify-content: space-between;
  margin-bottom: 8px;
  font-size: 0.875rem;
}

.info-item .label {
  color: var(--text-muted);
}

.info-item .value {
  font-weight: 600;
}

.card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 20px;
  border-top: 1px solid #f1f5f9;
}

.card-footer .date {
  font-size: 0.875rem;
  color: var(--text-muted);
  font-weight: 500;
}

/* Footer */
.footer {
  background: white;
  border-top: 1px solid #e2e8f0;
  padding: 40px 0;
  margin-top: 80px;
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.footer-logo {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--primary-color);
}

.footer p {
  color: var(--text-muted);
  font-size: 0.875rem;
}

.social-links a {
  margin-left: 20px;
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.875rem;
}

/* Responsive */
@media (max-width: 768px) {
  .hero h1 {
    font-size: 2rem;
  }
  .navbar nav {
    display: none;
  }
  .announcement-grid {
    grid-template-columns: 1fr;
  }
  .footer-content {
    flex-direction: column;
    gap: 20px;
    text-align: center;
  }
}