:root {
  --bg: #ffffff;
  --text: #1a1a1a;
  --text-muted: #666666;
  --accent: #3b82f6;
  --card-bg: #f8f9fa;
  --border: #eaeaea;
  --font-main: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

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

body {
  font-family: var(--font-main);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a { text-decoration: none; color: inherit; transition: color 0.2s; }
a:hover { color: var(--accent); }

/* Header */
.blog-header {
  padding: 40px 20px;
  text-align: center;
  border-bottom: 0px solid var(--border);
}
.blog-header h1 { font-size: 2.5rem; font-weight: 800; letter-spacing: -0.03em; }
.blog-header p { color: var(--text-muted); margin-top: 8px; font-size: 1.1rem; }

/* Container */
.container { max-width: 900px; margin: 0 auto; padding: 40px 20px; }

/* Grid (Index page) */
.posts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 32px;
}

.post-card {
  background: var(--bg);
  border-radius: 12px;
  overflow: hidden;
  border: 1px solid var(--border);
  transition: transform 0.2s, box-shadow 0.2s;
  display: flex;
  flex-direction: column;
}
.post-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 24px rgba(0,0,0,0.06);
}

.card-visual-abstract {
  height: 160px;
  width: 100%;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  position: relative;
  overflow: hidden;
}

.card-visual-abstract::before {
  content: '';
  position: absolute;
  width: 100px;
  height: 100px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.1);
  top: -20px;
  right: -20px;
}

.card-visual-abstract .grid-overlay {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-image: 
    linear-gradient(rgba(255, 255, 255, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.05) 1px, transparent 1px);
  background-size: 20px 20px;
}

.card-content { padding: 24px; flex: 1; display: flex; flex-direction: column; }
.card-date { font-size: 0.85rem; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.05em; font-weight: 600; margin-bottom: 8px; }
.card-title { font-size: 1.25rem; font-weight: 700; margin-bottom: 12px; line-height: 1.3; }
.card-excerpt { font-size: 0.95rem; color: var(--text-muted); flex: 1; }
.card-link { margin-top: 20px; font-weight: 600; color: var(--accent); font-size: 0.95rem; }

/* Single Post Page */
.post-header { max-width: 700px; margin: 0 auto 40px; text-align: center; }
.post-date { color: var(--text-muted); font-size: 0.9rem; margin-bottom: 12px; display: block; }
.post-title { font-size: 3rem; font-weight: 800; letter-spacing: -0.03em; line-height: 1.1; margin-bottom: 24px; }

.post-visual-abstract {
  width: 100%;
  max-width: 800px;
  height: 300px;
  margin: 0 auto 48px;
  border-radius: 16px;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  position: relative;
  overflow: hidden;
}

.post-visual-abstract::before,
.post-visual-abstract::after {
  content: '';
  position: absolute;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.1);
  animation: float 20s infinite ease-in-out;
}

.post-visual-abstract::before {
  width: 200px;
  height: 200px;
  top: -50px;
  left: -50px;
  animation-delay: 0s;
}

.post-visual-abstract::after {
  width: 150px;
  height: 150px;
  bottom: -30px;
  right: 10%;
  animation-delay: 5s;
}

.post-visual-abstract .shape-1,
.post-visual-abstract .shape-2,
.post-visual-abstract .shape-3 {
  position: absolute;
  background: rgba(255, 255, 255, 0.08);
  border-radius: 8px;
}

.post-visual-abstract .shape-1 {
  width: 80px;
  height: 80px;
  top: 20%;
  right: 20%;
  transform: rotate(45deg);
  animation: rotate 30s infinite linear;
}

.post-visual-abstract .shape-2 {
  width: 60px;
  height: 60px;
  bottom: 30%;
  left: 15%;
  border-radius: 50%;
  animation: float 15s infinite ease-in-out reverse;
}

.post-visual-abstract .shape-3 {
  width: 100px;
  height: 4px;
  top: 50%;
  left: 10%;
  background: rgba(255, 255, 255, 0.15);
  animation: slide 10s infinite ease-in-out;
}

.post-visual-abstract .grid-overlay {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-image: 
    linear-gradient(rgba(255, 255, 255, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.05) 1px, transparent 1px);
  background-size: 40px 40px;
  opacity: 0.5;
}

@keyframes float {
  0%, 100% { transform: translate(0, 0) scale(1); }
  50% { transform: translate(30px, -30px) scale(1.1); }
}

@keyframes rotate {
  from { transform: rotate(45deg); }
  to { transform: rotate(405deg); }
}

@keyframes slide {
  0%, 100% { transform: translateX(0); opacity: 0.15; }
  50% { transform: translateX(100px); opacity: 0.3; }
}

.post-content {
  max-width: 700px; margin: 0 auto;
  font-size: 1.125rem; line-height: 1.8; color: #333;
}
.post-content h2 { font-size: 1.75rem; font-weight: 700; margin: 48px 0 16px; letter-spacing: -0.02em; }
.post-content p { margin-bottom: 24px; }
.post-content em { color: var(--text-muted); font-style: italic; display: block; padding-left: 16px; border-left: 3px solid var(--accent); margin: 24px 0; }
.post-content code { background: #f1f5f9; padding: 2px 6px; border-radius: 4px; font-family: monospace; font-size: 0.9em; }

.back-link {
  display: inline-flex; align-items: center; gap: 8px;
  margin-bottom: 32px; font-weight: 600; color: var(--text-muted);
}
.back-link:hover { color: var(--text); }

/* Loading state */
.loading { text-align: center; padding: 60px; color: var(--text-muted); font-size: 1.2rem; }