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

:root {
  --bg-primary:        #0f1117;
  --bg-secondary:      #1a1d27;
  --bg-tertiary:       #2d3748;
  --border:            #2d3748;
  --border-light:      #4a5568;
  --text-primary:      #e2e8f0;
  --text-secondary:    #cbd5e0;
  --text-muted:        #a0aec0;
  --text-dim:          #718096;
  --text-faint:        #4a5568;
  --accent:            #63b3ed;
  --accent-link:       #90cdf4;
  --article-bg:        #0f1117;
  --input-bg:          #2d3748;
  --input-border:      #4a5568;
  --btn-primary:       #2b6cb0;
  --btn-primary-hover: #3182ce;
  --btn-muted:         #2d3748;
  --btn-muted-hover:   #4a5568;
  --btn-green:         #276749;
  --btn-green-hover:   #2f855a;
  --btn-amber:         #744210;
  --btn-amber-hover:   #975a16;
  --badge-bg:          #2d3748;
  --badge-text:        #a0aec0;
  --rank-color:        #f6ad55;
}

body.light {
  --bg-primary:        #f7fafc;
  --bg-secondary:      #ffffff;
  --bg-tertiary:       #edf2f7;
  --border:            #e2e8f0;
  --border-light:      #cbd5e0;
  --text-primary:      #1a202c;
  --text-secondary:    #2d3748;
  --text-muted:        #4a5568;
  --text-dim:          #718096;
  --text-faint:        #a0aec0;
  --accent:            #2b6cb0;
  --accent-link:       #2c5282;
  --article-bg:        #f0f4f8;
  --input-bg:          #ffffff;
  --input-border:      #cbd5e0;
  --btn-primary:       #2b6cb0;
  --btn-primary-hover: #2c5282;
  --btn-muted:         #e2e8f0;
  --btn-muted-hover:   #cbd5e0;
  --btn-green:         #276749;
  --btn-green-hover:   #2f855a;
  --btn-amber:         #c05621;
  --btn-amber-hover:   #9c4221;
  --badge-bg:          #e2e8f0;
  --badge-text:        #4a5568;
  --rank-color:        #c05621;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  transition: background 0.2s, color 0.2s;
}

header {
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border);
  padding: 1.25rem 1.5rem;
}

.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.brand { display: flex; flex-direction: column; gap: 0.15rem; }
h1 { font-size: 1.5rem; color: var(--accent); font-weight: 700; cursor: pointer; }
h1:hover { text-decoration: underline; }
.tagline { font-size: 0.75rem; color: var(--text-dim); letter-spacing: 0.03em; }

.controls { display: flex; align-items: center; gap: 0.5rem; flex-wrap: wrap; }
.controls label { font-size: 0.875rem; color: var(--text-muted); }

#datePicker {
  background: var(--input-bg);
  color: var(--text-primary);
  border: 1px solid var(--input-border);
  border-radius: 6px;
  padding: 0.35rem 0.6rem;
  font-size: 0.875rem;
}

button {
  background: var(--btn-primary);
  color: #fff;
  border: none;
  border-radius: 6px;
  padding: 0.4rem 1rem;
  cursor: pointer;
  font-size: 0.875rem;
  transition: background 0.15s;
}
button:hover { background: var(--btn-primary-hover); }

.about-toggle, .lang-toggle, .theme-toggle {
  background: var(--btn-muted);
  color: var(--text-primary);
  min-width: 4.5rem;
}
.about-toggle:hover, .lang-toggle:hover, .theme-toggle:hover {
  background: var(--btn-muted-hover);
}

.digest-date {
  max-width: 1200px;
  margin: 0.4rem auto 0;
  font-size: 0.85rem;
  color: var(--text-dim);
}

.about-panel {
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border);
}
.about-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}
.about-inner h2 { font-size: 1rem; color: var(--accent); }
.about-inner p, .about-inner li {
  font-size: 0.875rem;
  line-height: 1.6;
  color: var(--text-muted);
}
.about-inner ul { padding-left: 1.25rem; }
.about-inner a { color: var(--accent-link); }
.about-footer { font-style: italic; color: var(--text-dim) !important; }

.arch-title { font-size: 0.9rem; color: var(--accent); margin-top: 0.5rem; }
.arch-diagram {
  font-family: "Consolas", "Courier New", monospace;
  font-size: 0.72rem;
  line-height: 1.4;
  color: var(--text-secondary);
  background: var(--article-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1rem 1.25rem;
  overflow-x: auto;
  white-space: pre;
}

.site-footer {
  text-align: center;
  padding: 1.5rem;
  font-size: 0.75rem;
  color: var(--text-faint);
  border-top: 1px solid var(--border);
  margin-top: 3rem;
}

main { max-width: 1200px; margin: 2rem auto; padding: 0 1.5rem; }

.loading, .error {
  text-align: center;
  padding: 3rem;
  font-size: 1.1rem;
  color: var(--text-muted);
}
.error { color: #fc8181; }

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(500px, 1fr));
  gap: 1.25rem;
}

.card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.card-header { display: flex; justify-content: space-between; align-items: center; }
.card-title { font-size: 1rem; font-weight: 600; color: var(--accent); }
.card-badge {
  font-size: 0.7rem;
  background: var(--badge-bg);
  color: var(--badge-text);
  padding: 0.15rem 0.5rem;
  border-radius: 99px;
}
.card-overview { font-size: 0.875rem; line-height: 1.6; color: var(--text-secondary); }

.deep-dive-btn {
  align-self: flex-start;
  background: var(--btn-green);
  font-size: 0.8rem;
  padding: 0.35rem 0.8rem;
}
.deep-dive-btn:hover { background: var(--btn-green-hover); }
.deep-dive-btn.open { background: var(--btn-amber); }
.deep-dive-btn.open:hover { background: var(--btn-amber-hover); }

.articles {
  display: none;
  flex-direction: column;
  gap: 1rem;
  border-top: 1px solid var(--border);
  padding-top: 1rem;
}
.articles.visible { display: flex; }

.article {
  background: var(--article-bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.75rem;
}
.article-rank {
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--rank-color);
  text-transform: uppercase;
  margin-bottom: 0.25rem;
}
.article-title { font-size: 0.875rem; font-weight: 600; margin-bottom: 0.4rem; }
.article-title a { color: var(--accent-link); text-decoration: none; }
.article-title a:hover { text-decoration: underline; }
.article-summary { font-size: 0.8rem; line-height: 1.55; color: var(--text-muted); }

.back-btn {
  background: var(--btn-muted);
  color: var(--text-primary);
  margin-bottom: 1.5rem;
}
.back-btn:hover { background: var(--btn-muted-hover); }

.monthly-content {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1.5rem;
}
#monthlyTitle { font-size: 1.2rem; color: var(--accent); margin-bottom: 1rem; }
#monthlyContent {
  font-size: 0.9rem;
  line-height: 1.7;
  color: var(--text-secondary);
  white-space: pre-wrap;
}

@media (max-width: 600px) {
  .grid { grid-template-columns: 1fr; }
  .header-inner { flex-direction: column; align-items: flex-start; }
}