/* =============================================
   NOTEBOOK — Hard-Core Minimal Style
   ============================================= */

:root {
  --bg:        #0a0a0a;
  --surface:   #111111;
  --border:    #222222;
  --border-hi: #333333;
  --text:      #d4d4d4;
  --text-dim:  #666666;
  --accent:    #e8e8e8;
  --green:     #4ec9b0;
  --yellow:    #dcdcaa;
  --blue:      #9cdcfe;
  --red:       #f44747;
  --orange:    #ce9178;
  --mono:      'JetBrains Mono', 'Fira Code', 'Cascadia Code', 'Consolas', monospace;
  --sans:      'Inter', 'Segoe UI', system-ui, sans-serif;
  --max-w:     760px;
  --max-w-post: 720px;
}

/* ---- Reset ---- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: smooth; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--mono);
  line-height: 1.7;
  min-height: 100vh;
  overflow-x: hidden;
  position: relative;
}

/* ---- CRT Scanline overlay ---- */
.scanline {
  pointer-events: none;
  position: fixed;
  inset: 0;
  background: repeating-linear-gradient(
    0deg,
    transparent,
    transparent 2px,
    rgba(0,0,0,0.07) 2px,
    rgba(0,0,0,0.07) 4px
  );
  z-index: 9999;
  opacity: 0.35;
}

/* ---- Container ---- */
.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* =============================================
   HEADER
   ============================================= */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  padding: 1rem 0;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.logo {
  text-decoration: none;
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--accent);
}
.logo-bracket { color: var(--green); }
.logo-text { color: var(--accent); }
.logo:hover .logo-text { color: var(--green); transition: color 0.15s; }

.nav {
  display: flex;
  gap: 1.5rem;
  align-items: center;
}
.nav-link {
  text-decoration: none;
  font-size: 0.82rem;
  color: var(--text-dim);
  letter-spacing: 0.04em;
  transition: color 0.15s;
}
.nav-link:hover, .nav-link.active { color: var(--green); }

/* =============================================
   MAIN
   ============================================= */
.main { padding: 3rem 0 4rem; }

/* Hero */
.hero { margin-bottom: 3.5rem; }

.terminal-prompt {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  margin-bottom: 1rem;
}
.prompt-symbol {
  color: var(--green);
  font-size: 1rem;
  font-weight: 700;
}
.prompt-text {
  color: var(--accent);
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.05em;
}
.hero-body {
  border-left: 2px solid var(--border-hi);
  padding-left: 1rem;
}
.hero-desc {
  font-size: 0.92rem;
  color: var(--text-dim);
  line-height: 1.9;
}
.hero-desc .dim { color: #444; font-size: 0.85em; }

/* Profile block */
.profile-block {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  margin-bottom: 1.25rem;
}
.profile-name {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: 0.04em;
  margin-bottom: 0.2rem;
}
.profile-name-en {
  font-size: 0.85rem;
  color: var(--text-dim);
  font-weight: 400;
  letter-spacing: 0.06em;
}
.profile-line {
  display: flex;
  align-items: baseline;
  gap: 0.5rem;
  font-size: 0.85rem;
}
.profile-key {
  color: var(--blue);
  font-size: 0.8rem;
  white-space: pre;
  letter-spacing: 0.02em;
  min-width: 7.5rem;
}
.profile-sep {
  color: #444;
  flex-shrink: 0;
}
.profile-val {
  color: var(--text-dim);
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  align-items: center;
}
.profile-highlight {
  color: var(--green);
  font-weight: 700;
}
.tag-inline {
  font-size: 0.75rem;
  color: var(--green);
  background: rgba(78,201,176,0.07);
  border: 1px solid rgba(78,201,176,0.2);
  padding: 0.05em 0.55em;
  border-radius: 2px;
  letter-spacing: 0.03em;
  white-space: nowrap;
}

/* Blog desc */
.blog-desc {
  border-left: 2px solid var(--border-hi);
  padding-left: 1rem;
  margin-top: 0.25rem;
}
.blog-desc-text {
  font-size: 0.85rem;
  color: var(--text-dim);
  line-height: 1.8;
  margin-top: 0.35rem;
}
.blog-desc-text .dim { color: #444; font-size: 0.88em; }

/* Section headers */
.section { margin-bottom: 3rem; }
.section-header {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border);
}
.section-tag {
  color: var(--yellow);
  font-size: 0.82rem;
  font-weight: 700;
}
.section-title {
  color: var(--text-dim);
  font-size: 0.82rem;
}

/* Post Cards */
.post-list { display: flex; flex-direction: column; gap: 1.5rem; }

.post-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-left: 3px solid var(--green);
  padding: 1.25rem 1.5rem;
  transition: border-color 0.15s, background 0.15s;
}
.post-card:hover {
  border-left-color: var(--yellow);
  background: #161616;
}

.post-meta {
  display: flex;
  gap: 0.75rem;
  align-items: center;
  margin-bottom: 0.5rem;
}
.post-date {
  font-size: 0.75rem;
  color: var(--text-dim);
  letter-spacing: 0.05em;
}
.post-tag {
  font-size: 0.72rem;
  color: var(--green);
  background: rgba(78,201,176,0.07);
  border: 1px solid rgba(78,201,176,0.2);
  padding: 0.05em 0.55em;
  border-radius: 2px;
  letter-spacing: 0.04em;
}

.post-title {
  font-size: 1rem;
  font-weight: 600;
  line-height: 1.4;
  margin-bottom: 0.6rem;
}
.post-title a {
  color: var(--accent);
  text-decoration: none;
}
.post-title a:hover { color: var(--yellow); }

.post-excerpt {
  font-size: 0.83rem;
  color: var(--text-dim);
  line-height: 1.7;
  margin-bottom: 0.75rem;
}

.post-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.read-more {
  font-size: 0.8rem;
  color: var(--green);
  text-decoration: none;
  letter-spacing: 0.05em;
}
.read-more:hover { color: var(--yellow); }
.post-length {
  font-size: 0.75rem;
  color: #444;
}

/* Tags */
.tag-list { display: flex; flex-wrap: wrap; gap: 0.6rem; }
.tag {
  font-size: 0.78rem;
  color: var(--text-dim);
  border: 1px solid var(--border-hi);
  padding: 0.2em 0.75em;
  text-decoration: none;
  transition: color 0.15s, border-color 0.15s;
  letter-spacing: 0.03em;
}
.tag:hover { color: var(--accent); border-color: var(--accent); }

/* =============================================
   FOOTER
   ============================================= */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 1.25rem 0;
}
.footer-text {
  font-size: 0.75rem;
  color: #444;
  letter-spacing: 0.04em;
}

/* =============================================
   NOTES LIST PAGE
   ============================================= */
.page-title-block { margin-bottom: 2.5rem; }
.page-command {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.5rem;
}
.page-command-sym { color: var(--green); font-size: 1rem; font-weight: 700; }
.page-command-text { color: var(--accent); font-size: 1rem; font-weight: 700; }
.page-subtitle { font-size: 0.82rem; color: var(--text-dim); }

.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 2rem;
}
.filter-btn {
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--text-dim);
  background: transparent;
  border: 1px solid var(--border-hi);
  padding: 0.25em 0.8em;
  cursor: pointer;
  transition: color 0.15s, border-color 0.15s;
  letter-spacing: 0.03em;
}
.filter-btn:hover, .filter-btn.active { color: var(--green); border-color: var(--green); }

/* =============================================
   ABOUT PAGE
   ============================================= */
.about-block { max-width: 600px; }
.about-block h2 {
  font-size: 0.9rem;
  color: var(--yellow);
  letter-spacing: 0.06em;
  margin: 2rem 0 0.75rem;
  text-transform: uppercase;
}
.about-block p {
  font-size: 0.88rem;
  color: var(--text-dim);
  line-height: 1.8;
  margin-bottom: 0.75rem;
}
.about-block a { color: var(--green); text-decoration: none; }
.about-block a:hover { text-decoration: underline; }

/* =============================================
   POST PAGE
   ============================================= */
.post-page { max-width: var(--max-w-post); margin: 0 auto; padding: 0 1.5rem; }

.post-header { margin-bottom: 2.5rem; padding-bottom: 1.5rem; border-bottom: 1px solid var(--border); }
.post-header .post-meta { margin-bottom: 1rem; }
.post-header h1 {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--accent);
  line-height: 1.35;
  letter-spacing: -0.01em;
  margin-bottom: 0.75rem;
}

.toc {
  background: var(--surface);
  border: 1px solid var(--border);
  border-left: 3px solid var(--border-hi);
  padding: 1rem 1.25rem;
  margin-bottom: 2.5rem;
  font-size: 0.82rem;
}
.toc-title {
  color: var(--yellow);
  font-weight: 700;
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-bottom: 0.75rem;
}
.toc ol, .toc ul { padding-left: 1.2em; }
.toc li { margin-bottom: 0.25rem; }
.toc a { color: var(--text-dim); text-decoration: none; }
.toc a:hover { color: var(--green); }

/* Article body */
.article-body {
  font-size: 0.92rem;
  line-height: 1.9;
  color: var(--text);
}
.article-body h2 {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--accent);
  margin: 2.5rem 0 0.75rem;
  padding-bottom: 0.4rem;
  border-bottom: 1px solid var(--border);
}
.article-body h3 {
  font-size: 0.98rem;
  font-weight: 700;
  color: var(--yellow);
  margin: 2rem 0 0.6rem;
  letter-spacing: 0.02em;
}
.article-body h4 {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--blue);
  margin: 1.5rem 0 0.5rem;
}
.article-body p { margin-bottom: 1rem; }
.article-body strong { color: var(--accent); }
.article-body em { color: var(--orange); font-style: italic; }
.article-body u { color: var(--green); text-decoration: underline; }

/* Inline code */
.article-body code {
  font-family: var(--mono);
  font-size: 0.85em;
  background: #1a1a1a;
  border: 1px solid var(--border-hi);
  padding: 0.1em 0.4em;
  color: var(--blue);
  border-radius: 2px;
}

/* Code blocks */
.article-body pre {
  background: #111;
  border: 1px solid var(--border);
  border-left: 3px solid var(--green);
  padding: 1rem 1.25rem;
  overflow-x: auto;
  margin: 1.25rem 0;
  font-size: 0.85rem;
}
.article-body pre code {
  background: none;
  border: none;
  padding: 0;
  color: var(--text);
}

/* Blockquotes */
.article-body blockquote {
  border-left: 3px solid var(--border-hi);
  padding: 0.5rem 1rem;
  margin: 1.25rem 0;
  color: var(--text-dim);
  font-size: 0.88rem;
}

/* Lists */
.article-body ul, .article-body ol {
  padding-left: 1.5rem;
  margin-bottom: 1rem;
}
.article-body li { margin-bottom: 0.35rem; }

/* Math display blocks — KaTeX */
.article-body .katex-display {
  margin: 1.5rem 0;
  overflow-x: auto;
  padding: 0.75rem 0;
}
.article-body .katex { font-size: 1em; }

/* Note callout boxes */
.note-box {
  background: rgba(78,201,176,0.05);
  border: 1px solid rgba(78,201,176,0.2);
  border-left: 3px solid var(--green);
  padding: 0.75rem 1rem;
  margin: 1.25rem 0;
  font-size: 0.86rem;
  color: var(--text-dim);
}
.note-box .note-label {
  color: var(--green);
  font-weight: 700;
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  display: block;
  margin-bottom: 0.3rem;
}
.tip-box {
  background: rgba(220,220,170,0.05);
  border: 1px solid rgba(220,220,170,0.2);
  border-left: 3px solid var(--yellow);
  padding: 0.75rem 1rem;
  margin: 1.25rem 0;
  font-size: 0.86rem;
  color: var(--text-dim);
}
.tip-box .tip-label {
  color: var(--yellow);
  font-weight: 700;
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  display: block;
  margin-bottom: 0.3rem;
}

/* Section divider */
.article-body hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 2.5rem 0;
}

/* Back nav */
.back-nav { margin-bottom: 2rem; }
.back-link {
  font-size: 0.82rem;
  color: var(--text-dim);
  text-decoration: none;
  letter-spacing: 0.04em;
}
.back-link:hover { color: var(--green); }

/* =============================================
   RESPONSIVE
   ============================================= */
@media (max-width: 600px) {
  .header-inner { flex-direction: column; align-items: flex-start; gap: 0.6rem; }
  .nav { gap: 1rem; }
  .post-header h1 { font-size: 1.15rem; }
  .section-header { flex-wrap: wrap; }
}