:root {
  --bg-color: #ffffff;
  --text-color: #333333;
  --accent-color: #1A4D2E; /* Deep Green */
  --secondary-color: #666666;
  --link-color: #1A4D2E;
  --hover-color: #4F775D;
  --border-color: #eeeeee;
  --font-main: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  --max-width: 800px;
}

body {
  font-family: var(--font-main);
  background-color: var(--bg-color);
  color: var(--text-color);
  line-height: 1.7;
  margin: 0;
  padding: 0;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 3rem 1.5rem;
}

/* Header */
header {
  margin-bottom: 4rem;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 1rem;
}

.site-title {
  font-size: 1.6rem;
  font-weight: 700;
  text-decoration: none;
  color: var(--text-color);
  letter-spacing: -0.5px;
  border-bottom: none;
}

.site-title:hover {
  text-decoration: none; /* No underline on hover */
  color: var(--text-color); /* Keep color consistent or minimal change */
  opacity: 0.8;
}

nav a {
  margin-left: 1.5rem;
  text-decoration: none;
  color: var(--secondary-color);
  font-size: 0.95rem;
  font-weight: 500;
}

nav a:first-child {
    margin-left: 0; /* Reset for mobile wrap if needed, usually handled by flex gap */
}

nav a:hover {
  color: var(--accent-color);
  text-decoration: none;
}

/* Typography */
h1, h2, h3 {
  font-weight: 600;
  letter-spacing: -0.5px;
  margin-top: 2.5rem;
  margin-bottom: 1rem;
  color: #222;
}

a {
  color: var(--link-color);
  text-decoration: none;
  transition: opacity 0.2s, color 0.2s;
}

a:hover {
  color: var(--hover-color);
  text-decoration: underline;
}

/* Post List */
.post-list {
  list-style: none;
  padding: 0;
  margin-top: 2rem;
}

.post-item {
  display: flex;
  align-items: baseline;
  padding: 0.6rem 0;
}

.post-date {
  flex-shrink: 0;
  width: 140px;
  color: var(--secondary-color);
  font-family: monospace;
  font-size: 0.9rem;
}

.post-title {
  font-size: 1.1rem;
  font-weight: 500;
  color: var(--link-color);
}

.post-title:hover {
  text-decoration: underline;
}

.post-tag {
  font-size: 0.75rem;
  background-color: #f4f4f4;
  color: var(--secondary-color);
  padding: 2px 8px;
  border-radius: 4px;
  margin-left: 12px;
  vertical-align: middle;
  text-transform: uppercase;
  font-weight: 500;
  letter-spacing: 0.5px;
}

.post-tag.paper {
  background-color: #e8f5e9;
  color: var(--accent-color);
}

/* Single Post */
.post-header {
  margin-bottom: 2.5rem;
  text-align: left;
}

.post-meta {
  color: var(--secondary-color);
  font-size: 0.95rem;
  margin-bottom: 0.5rem;
  display: block;
  font-family: monospace;
}

.content {
  font-size: 1.05rem;
}

.content h2 {
    font-size: 1.5rem;
    color: var(--accent-color);
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.5rem;
}

.content p {
    margin-bottom: 1.5rem;
}

.footer {
  margin-top: 5rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
  text-align: center;
  font-size: 0.85rem;
  color: var(--secondary-color);
}

/* Responsive */
@media (max-width: 600px) {
  .container {
    padding: 2rem 1.25rem;
  }

  header {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.5rem;
    margin-bottom: 3rem;
  }

  nav {
    margin-top: 0.5rem;
  }

  nav a {
    margin-left: 0;
    margin-right: 1.25rem;
  }
  
  .post-item {
    flex-direction: column;
    align-items: flex-start;
    padding: 1rem 0;
    border-bottom: 1px solid #f9f9f9;
  }

  .post-date {
    margin-bottom: 0.25rem;
    font-size: 0.85rem;
  }
  
  .post-title {
    font-size: 1.15rem;
  }

  .post-tag {
    margin-left: 0;
    margin-top: 0.3rem;
    display: inline-block;
  }
}