/* ========== Reset & Base ========== */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }

:root {
  --bg: #f8f9fa;
  --bg-card: #ffffff;
  --text: #1a1a2e;
  --text-secondary: #6c757d;
  --accent: #4361ee;
  --accent-hover: #3a56d4;
  --border: #e9ecef;
  --radius: 12px;
  --shadow: 0 2px 8px rgba(0,0,0,0.06);
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.container {
  max-width: 780px;
  margin: 0 auto;
  padding: 0 20px;
  width: 100%;
}

/* ========== Header ========== */
.site-header {
  padding: 48px 0 32px;
  text-align: center;
  border-bottom: 1px solid var(--border);
  background: var(--bg-card);
}

.site-title {
  font-size: 28px;
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
}

.site-title:hover { color: var(--accent); }

.site-desc {
  margin-top: 8px;
  font-size: 15px;
  color: var(--text-secondary);
}

/* ========== Main ========== */
main {
  flex: 1;
  padding: 32px 0;
}

/* ========== Article Card ========== */
.article-list {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.article-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  box-shadow: var(--shadow);
  cursor: pointer;
  transition: transform 0.2s, box-shadow 0.2s;
  text-decoration: none;
  color: inherit;
  display: block;
}

.article-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 16px rgba(0,0,0,0.1);
}

.article-card h2 {
  font-size: 20px;
  font-weight: 600;
  margin-bottom: 8px;
}

.article-card .meta {
  font-size: 13px;
  color: var(--text-secondary);
  margin-bottom: 12px;
}

.article-card .summary {
  font-size: 15px;
  color: var(--text-secondary);
  line-height: 1.6;
}

.tag {
  display: inline-block;
  background: #eef1ff;
  color: var(--accent);
  font-size: 12px;
  padding: 2px 10px;
  border-radius: 20px;
  margin-left: 8px;
}

/* ========== Article Detail ========== */
.back-btn {
  display: inline-block;
  color: var(--accent);
  text-decoration: none;
  font-size: 14px;
  margin-bottom: 24px;
}

.back-btn:hover { text-decoration: underline; }

.article-detail h1 {
  font-size: 26px;
  font-weight: 700;
  margin-bottom: 8px;
}

.article-detail .meta {
  font-size: 13px;
  color: var(--text-secondary);
  margin-bottom: 32px;
}

.article-body h2 { font-size: 20px; margin: 28px 0 12px; }
.article-body h3 { font-size: 17px; margin: 24px 0 10px; }
.article-body p { margin-bottom: 16px; }
.article-body ul, .article-body ol { margin: 0 0 16px 24px; }
.article-body li { margin-bottom: 6px; }
.article-body strong { color: var(--text); }

.article-body code {
  background: #f1f3f5;
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 14px;
}

.article-body blockquote {
  border-left: 3px solid var(--accent);
  padding: 12px 20px;
  margin: 16px 0;
  background: #f8f9ff;
  color: var(--text-secondary);
}

/* ========== Footer ========== */
.site-footer {
  padding: 24px 0;
  text-align: center;
  border-top: 1px solid var(--border);
  margin-top: 40px;
}

.site-footer a {
  font-size: 13px;
  color: var(--text-secondary);
  text-decoration: none;
}

.site-footer a:hover { color: var(--accent); }

/* ========== Responsive ========== */
@media (max-width: 600px) {
  .site-header { padding: 32px 0 20px; }
  .site-title { font-size: 22px; }
  .article-card { padding: 20px; }
  .article-detail h1 { font-size: 22px; }
}