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

body {
  font-family: "Times New Roman", Times, serif;
  background-color: #eef4fb;
  color: #1a1a2e;
  line-height: 1.75;
}

a {
  color: #2a6cb0;
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

/* Layout */
header, main, footer {
  max-width: 680px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Header */
header {
  padding-top: 3rem;
  padding-bottom: 2rem;
  border-bottom: 1px solid #c2d9f0;
}

header h1 {
  font-size: 1.8rem;
  font-weight: normal;
  letter-spacing: 0.01em;
}

header h1 a {
  color: #1a1a2e;
}

header nav {
  margin-top: 0.5rem;
  font-size: 0.95rem;
  color: #4a6fa5;
}

header nav a {
  margin-right: 1.2rem;
  color: #4a6fa5;
}

/* Main */
main {
  padding-top: 2.5rem;
  padding-bottom: 3rem;
  min-height: calc(100vh - 200px);
}

/* Post list */
.post-list {
  list-style: none;
}

.post-list li {
  padding: 1.5rem 0;
  border-bottom: 1px solid #c2d9f0;
}

.post-list li:last-child {
  border-bottom: none;
}

.post-list .post-date {
  font-size: 0.85rem;
  color: #6b88a8;
  display: block;
  margin-bottom: 0.3rem;
}

.post-list .post-title {
  font-size: 1.25rem;
}

.post-list .post-excerpt {
  margin-top: 0.4rem;
  font-size: 0.95rem;
  color: #3a4a60;
}

/* Individual post */
.post-header {
  margin-bottom: 2rem;
}

.post-header h1 {
  font-size: 2rem;
  font-weight: normal;
  line-height: 1.3;
}

.post-header .post-date {
  margin-top: 0.5rem;
  font-size: 0.9rem;
  color: #6b88a8;
}

.post-body p {
  margin-bottom: 1.25rem;
}

.post-body h2 {
  font-size: 1.35rem;
  font-weight: normal;
  margin: 2rem 0 0.75rem;
  color: #2a4a70;
}

.post-body ul, .post-body ol {
  margin: 0 0 1.25rem 1.5rem;
}

.post-body blockquote {
  border-left: 3px solid #a0c4e8;
  padding-left: 1rem;
  color: #4a6080;
  margin: 1.25rem 0;
}

/* GitHub repo cards */
.github-card {
  display: block;
  border: 1px solid #c2d9f0;
  border-radius: 6px;
  padding: 1rem 1.1rem;
  margin: 1.5rem 0;
  text-decoration: none;
  color: inherit;
  background: #f4f9ff;
  transition: border-color 0.15s, box-shadow 0.15s;
}

.github-card:hover {
  border-color: #4a6fa5;
  box-shadow: 0 3px 10px rgba(42, 108, 176, 0.1);
  text-decoration: none;
}

.gh-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.4rem;
}

.gh-title {
  font-family: "Courier New", Courier, monospace;
  font-size: 0.95rem;
  color: #2a6cb0;
}

.gh-stars {
  font-size: 0.85rem;
  color: #6b88a8;
}

.gh-description {
  font-size: 0.9rem;
  color: #3a4a60;
  margin: 0.3rem 0 0.6rem;
}

.gh-footer {
  display: flex;
  justify-content: space-between;
  font-size: 0.8rem;
  color: #6b88a8;
}

.gh-lang::before {
  content: "● ";
  color: #4a6fa5;
}

/* Notes list */
.notes-list {
  list-style: none;
}

.notes-list li {
  padding: 1.2rem 0;
  border-bottom: 1px solid #c2d9f0;
  display: flex;
  align-items: baseline;
  gap: 1.2rem;
}

.notes-list li:last-child {
  border-bottom: none;
}

.notes-list .note-date {
  font-size: 0.85rem;
  color: #6b88a8;
  white-space: nowrap;
  flex-shrink: 0;
}

.notes-list .note-title {
  font-size: 1.1rem;
}

/* PDF viewer */
.pdf-viewer {
  display: block;
  width: 100%;
  height: calc(100vh - 240px);
  min-height: 500px;
  border: 1px solid #c2d9f0;
  border-radius: 4px;
}

/* File blocks */
.file-block {
  margin: 1.5rem 0;
  border: 1px solid #c2d9f0;
  border-radius: 4px;
  overflow: hidden;
}

.file-block summary {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 0.85rem;
  background: #dceaf7;
  cursor: pointer;
  user-select: none;
  list-style: none;
  font-family: "Courier New", Courier, monospace;
  font-size: 0.85rem;
  color: #2a4a70;
}

.file-block summary::-webkit-details-marker { display: none; }

.file-block summary::before {
  content: '▶';
  font-size: 0.65rem;
  color: #4a6fa5;
  transition: transform 0.15s ease;
  flex-shrink: 0;
}

.file-block[open] summary::before {
  transform: rotate(90deg);
}

.file-block summary:hover {
  background: #cde0f2;
}

.file-block pre {
  margin: 0 !important;
  border-radius: 0 !important;
  border-top: 1px solid #c2d9f0;
  max-height: 480px;
  overflow: auto !important;
}

/* Footer */
footer {
  padding: 1.5rem 1.5rem;
  border-top: 1px solid #c2d9f0;
  font-size: 0.85rem;
  color: #6b88a8;
  text-align: center;
}