:root {
  --text-color: #333;
  --bg-color: #fff;
  --border-color: #e0e0e0;
  --link-color: #0066cc;
  --link-hover-color: #004499;
  --code-bg: #f6f8fa;
  --date-color: #666;
  --footer-color: #888;
  --code-keyword: #0000ff;
  --code-string: #a31515;
  --code-comment: #008000;
  --code-function: #795e26;
  --code-number: #098658;
  --code-operator: #000000;
  --code-variable: #001080;
}

html.dark-theme {
  --text-color: #eee;
  --bg-color: #1a1a1a;
  --border-color: #333;
  --link-color: #66b3ff;
  --link-hover-color: #99ccff;
  --code-bg: #0d1117;
  --date-color: #999;
  --footer-color: #aaa;
  --code-keyword: #569cd6;
  --code-string: #ce9178;
  --code-comment: #6a9955;
  --code-function: #dcdcaa;
  --code-number: #b5cea8;
  --code-operator: #d4d4d4;
  --code-variable: #9cdcfe;
}

/* Base styles */
html,
body {
  font-family: system-ui, sans-serif;
  max-width: 70ch;
  padding: 1.5em 1em;
  margin: auto;
  line-height: 1.5;
  font-size: 1em;
  color: var(--text-color);
  background-color: var(--bg-color);
  transition: background-color 0.3s ease, color 0.3s ease;
}

/* Header & navigation */
header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 2em;
}

#head-link {
  color: var(--text-color);
  font-weight: bold;
  text-decoration: none;
}

.main-nav {
  display: flex;
  gap: 1.5em;
}

.nav-link {
  position: relative;
  color: var(--text-color);
  text-decoration: none;
  font-size: 0.95em;
  padding: 0.3em 0;
  transition: color 0.2s ease;
}

.nav-link::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--link-color);
  transition: width 0.2s ease;
}

.nav-link:hover {
  color: var(--link-color);
  text-decoration: none; /* disable generic underline */
}

.nav-link:hover::after {
  width: 100%;
}

.header-right {
  display: flex;
  align-items: center;
  gap: 1em;
}

#theme-toggle {
  background: none;
  border: none;
  color: var(--text-color);
  cursor: pointer;
  padding: 0.5em;
  font-size: 1.2em;
  transition: opacity 0.2s ease;
}

#theme-toggle:hover {
  opacity: 0.7;
}

.social-icons {
  display: flex;
  gap: 1em;
}

.social-icons a {
  color: var(--text-color);
  font-size: 1.2em;
  transition: opacity 0.2s ease;
}

.social-icons a:hover {
  opacity: 0.7;
}

/* Typography */
h1,
h2,
h3,
h4,
h5,
h6 {
  margin: 1.5em 0 0.5em;
}

p {
  margin-bottom: 1em;
}

/* Scoped in-content links */
.content a {
  color: var(--link-color);
  text-decoration: none;
  border-bottom: 1px solid var(--link-color);
  transition: border-color 0.2s ease, color 0.2s ease;
}

.content a:hover {
  border-bottom-color: var(--link-hover-color);
  color: var(--link-hover-color);
}

/* Post date */
.post-date {
  color: var(--date-color);
  font-size: 0.8em;
  margin-bottom: 1.5em;
  font-style: italic;
}

/* Code blocks */
pre {
  background: var(--code-bg);
  border-radius: 8px;
  margin: 1.5em 0;
  padding: 1.5em;
  overflow: auto;
  font-size: 0.9em;
  line-height: 1.5;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

code {
  font-family: "Fira Code", Consolas, Monaco, monospace;
  background: var(--code-bg);
  padding: 0.2em 0.4em;
  border-radius: 3px;
}

/* Syntax highlighting */
.token.comment {
  color: var(--code-comment);
  font-style: italic;
}

.token.keyword {
  color: var(--code-keyword);
}

.token.string {
  color: var(--code-string);
}

.token.function {
  color: var(--code-function);
}

.token.number,
.token.constant {
  color: var(--code-number);
}

.token.operator,
.token.punctuation {
  color: var(--code-operator);
}

.token.variable {
  color: var(--code-variable);
}

/* Dark theme overrides for hljs */
html.dark-theme .hljs {
  background: var(--code-bg);
  color: #c9d1d9;
}

html.dark-theme .hljs-keyword,
html.dark-theme .hljs-selector-tag,
html.dark-theme .hljs-subst {
  color: #ff7b72;
}

html.dark-theme .hljs-string,
html.dark-theme .hljs-doctag {
  color: #a5d6ff;
}

/* Images */
img {
  max-width: 100%;
  height: auto;
  display: block;
  margin: 1em auto;
}

/* Footer */
footer {
  margin-top: 2em;
  padding: 1em 0;
  border-top: 1px solid var(--border-color);
  color: var(--footer-color);
  font-size: 0.8em;
  text-align: center;
}