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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: #f8f9fa;
  color: #1a1a1a;
  line-height: 1.5;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.header {
  background: #ffffff;
  border-bottom: 1px solid #e8e8e8;
  padding: 1.25rem 1.5rem;
}

.header-inner {
  max-width: 960px;
  margin: 0 auto;
}

.title {
  font-size: 1.375rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  color: #111;
}

.subtitle {
  font-size: 0.8125rem;
  color: #666;
  margin-top: 0.25rem;
}

.main {
  flex: 1;
  max-width: 960px;
  width: 100%;
  margin: 0 auto;
  padding: 1.5rem;
}

.grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.75rem;
}

.card {
  display: flex;
  flex-direction: column;
  background: #ffffff;
  border: 1px solid #e8e8e8;
  border-radius: 8px;
  padding: 1rem;
  text-decoration: none;
  color: inherit;
  transition: border-color 0.15s, box-shadow 0.15s, transform 0.15s;
}

.card:hover {
  border-color: #ccc;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
  transform: translateY(-1px);
}

.card-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 0.5rem;
  margin-bottom: 0.5rem;
}

.card-title {
  font-size: 0.9375rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: #111;
}

.card-arrow {
  font-size: 0.875rem;
  color: #999;
  flex-shrink: 0;
  transition: color 0.15s, transform 0.15s;
}

.card:hover .card-arrow {
  color: #333;
  transform: translateX(2px);
}

.card-desc {
  font-size: 0.75rem;
  color: #666;
  flex: 1;
  margin-bottom: 0.75rem;
  line-height: 1.45;
}

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem;
}

.tag {
  font-size: 0.625rem;
  font-weight: 500;
  color: #555;
  background: #f3f3f3;
  border: 1px solid #e8e8e8;
  border-radius: 4px;
  padding: 0.125rem 0.375rem;
  letter-spacing: 0.01em;
}

.footer {
  text-align: center;
  padding: 1rem 1.5rem;
  font-size: 0.6875rem;
  color: #999;
  border-top: 1px solid #e8e8e8;
  background: #ffffff;
}

@media (max-width: 900px) {
  .grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 520px) {
  .grid {
    grid-template-columns: 1fr;
  }

  .main {
    padding: 1rem;
  }
}