/* ── Design Tokens ── */
:root {
  --bg: #ffffff;
  --surface: #f7f7f7;
  --surface-raised: #f0f0f0;
  --surface-hover: #e8e8e8;
  --border: #000000;
  --border-subtle: rgba(0, 0, 0, 0.1);
  --accent: #ff6b00;
  --accent-dim: rgba(255, 107, 0, 0.08);
  --text: #111111;
  --text-secondary: #444444;
  --text-muted: #888888;

  --font-display: 'DM Serif Display', 'Noto Serif SC', Georgia, serif;
  --font-body: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', 'Fira Code', monospace;

  --transition-fast: 0.15s ease;
  --transition-medium: 0.3s ease;
}

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

html {
  scroll-behavior: smooth;
}

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

a {
  color: inherit;
  text-decoration: none;
}

/* ── Noise Texture ── */
.noise-overlay {
  position: fixed;
  inset: 0;
  z-index: 9999;
  pointer-events: none;
  opacity: 0.025;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)'/%3E%3C/svg%3E");
  background-repeat: repeat;
  background-size: 128px 128px;
}

/* ── Custom Cursor ── */
@media (hover: hover) {
  body {
    cursor: none;
  }

  a, button, [data-link] {
    cursor: none;
  }
}

.cursor {
  width: 12px;
  height: 12px;
  border: 2px solid var(--accent);
  border-radius: 50%;
  position: fixed;
  pointer-events: none;
  z-index: 10000;
  transform: translate(-50%, -50%);
  transition: width var(--transition-fast), height var(--transition-fast), background var(--transition-fast), border-color var(--transition-fast);
}

.cursor--hover {
  width: 40px;
  height: 40px;
  background: var(--accent-dim);
  border-color: var(--accent);
}

/* ── Navigation ── */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--bg);
  border-bottom: 2px solid var(--border);
  padding: 1.25rem 2.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 1.125rem;
  letter-spacing: -0.02em;
}

.nav-brand__symbol {
  color: var(--accent);
  font-size: 1.25rem;
}

.nav-links {
  display: flex;
  gap: 2.5rem;
  list-style: none;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.nav-links a {
  color: var(--text-secondary);
  position: relative;
  transition: color var(--transition-fast);
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent);
  transition: width var(--transition-medium);
}

.nav-links a:hover {
  color: var(--accent);
}

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

/* ── Hero ── */
.hero {
  padding: 6rem 2.5rem 4rem;
  border-bottom: 2px solid var(--border-subtle);
  max-width: 1400px;
  margin: 0 auto;
}

.hero__title {
  font-family: var(--font-display);
  font-size: clamp(3.5rem, 10vw, 8rem);
  line-height: 0.95;
  letter-spacing: -0.03em;
  margin-bottom: 1.75rem;
  font-weight: 400;
}

.hero__subtitle {
  font-size: 1.125rem;
  color: var(--text-secondary);
  max-width: 520px;
  line-height: 1.7;
  margin-bottom: 3.5rem;
}

.hero__stats {
  display: flex;
  gap: 4rem;
}

.stat-item {
  display: flex;
  flex-direction: column;
  gap: 0.375rem;
}

.stat-item__num {
  font-family: var(--font-mono);
  font-size: 2.25rem;
  font-weight: 700;
  color: var(--accent);
  line-height: 1;
}

.stat-item__label {
  font-size: 0.6875rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.12em;
}

/* ── Category Filter ── */
.category-filter {
  max-width: 1400px;
  margin: 0 auto;
  padding: 2.5rem 2.5rem 0;
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
  border-bottom: 2px solid var(--border-subtle);
  padding-bottom: 2rem;
}

.category-btn {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  padding: 0.5rem 1.25rem;
  border: 2px solid var(--border-subtle);
  background: var(--bg);
  color: var(--text-secondary);
  transition: all var(--transition-fast);
}

.category-btn:hover {
  border-color: var(--border);
  transform: translate(-2px, -2px);
  box-shadow: 4px 4px 0px var(--accent);
  color: var(--text);
}

.category-btn--active {
  border-color: var(--border);
  background: var(--text);
  color: var(--bg);
  box-shadow: 4px 4px 0px var(--accent);
}

.category-btn--active:hover {
  background: var(--text);
  color: var(--bg);
}

/* ── Posts Grid ── */
.posts-grid {
  max-width: 1400px;
  margin: 0 auto;
  padding: 2px 2.5rem 0;
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: 2px;
  background: var(--bg);
}

.post-card {
  grid-column: span 4;
  background: var(--surface);
  padding: 2.5rem;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  border: 2px solid transparent;
  transition: transform var(--transition-medium), box-shadow var(--transition-medium), border-color var(--transition-medium), background var(--transition-medium);
  animation: slideUp 0.6s ease backwards;
}

.post-card:hover {
  border-color: var(--border);
  background: var(--surface-raised);
  transform: translate(-4px, -4px);
  box-shadow: 8px 8px 0px var(--accent);
}

.post-card--featured {
  grid-column: span 8;
}

.post-card__meta {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  display: flex;
  justify-content: space-between;
  letter-spacing: 0.02em;
}

.post-card__title {
  font-family: var(--font-display);
  font-size: 1.75rem;
  line-height: 1.2;
  font-weight: 400;
}

.post-card__title a {
  transition: color var(--transition-fast);
}

.post-card__title a:hover {
  color: var(--accent);
}

.post-card__excerpt {
  color: var(--text-secondary);
  font-size: 0.9375rem;
  line-height: 1.7;
  flex: 1;
}

.post-card__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: auto;
}

.tag {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  padding: 0.35rem 0.875rem;
  border: 1px solid var(--border-subtle);
  color: var(--text-secondary);
  background: var(--bg);
  transition: border-color var(--transition-fast), color var(--transition-fast), transform var(--transition-fast);
}

.tag:hover {
  border-color: var(--accent);
  color: var(--accent);
  transform: translateY(-1px);
}

/* ── Post Detail ── */
.post-detail {
  max-width: 720px;
  margin: 0 auto;
  padding: 4rem 2.5rem 6rem;
  animation: slideUp 0.5s ease;
}

.post-detail__header {
  margin-bottom: 3.5rem;
  padding-bottom: 2.5rem;
  border-bottom: 2px solid var(--border-subtle);
}

.post-detail__meta {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--text-muted);
  display: flex;
  gap: 1.5rem;
  flex-wrap: wrap;
  margin-bottom: 1.5rem;
}

.post-detail__title {
  font-family: var(--font-display);
  font-size: clamp(2.25rem, 5vw, 3.5rem);
  line-height: 1.1;
  font-weight: 400;
}

.post-detail__content {
  font-size: 1.0625rem;
  line-height: 1.85;
  color: var(--text-secondary);
}

.post-detail__content h2 {
  font-family: var(--font-display);
  color: var(--text);
  font-size: 1.875rem;
  margin: 3rem 0 1.25rem;
  font-weight: 400;
  line-height: 1.2;
}

.post-detail__content p {
  margin-bottom: 1.5rem;
}

.post-detail__content strong {
  color: var(--text);
  font-weight: 600;
}

.post-detail__content pre {
  background: #111111;
  border: 2px solid var(--border);
  padding: 1.5rem;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.875rem;
  line-height: 1.6;
  margin: 1.5rem 0;
  color: #f0f0f0;
}

.post-detail__content code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  color: var(--accent);
}

.post-detail__content pre code {
  color: inherit;
  font-size: inherit;
}

.post-detail__footer {
  margin-top: 4rem;
  padding-top: 2rem;
  border-top: 2px solid var(--border-subtle);
}

.back-link {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  color: var(--text-secondary);
  transition: color var(--transition-fast);
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}

.back-link:hover {
  color: var(--accent);
}

/* ── About ── */
.about {
  max-width: 680px;
  margin: 0 auto;
  padding: 6rem 2.5rem;
  animation: slideUp 0.5s ease;
}

.about__intro {
  font-family: var(--font-display);
  font-size: clamp(1.875rem, 4vw, 2.75rem);
  line-height: 1.25;
  margin-bottom: 2.5rem;
  font-weight: 400;
}

.about__text {
  color: var(--text-secondary);
  font-size: 1.0625rem;
  line-height: 1.85;
  margin-bottom: 1.5rem;
}

.about__stack {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 2rem;
}

.stack-tag {
  font-family: var(--font-mono);
  padding: 0.625rem 1.25rem;
  border: 2px solid var(--border);
  background: var(--bg);
  font-size: 0.875rem;
  color: var(--text);
  transition: transform var(--transition-medium), box-shadow var(--transition-medium), background var(--transition-fast);
}

.stack-tag:hover {
  transform: translate(-3px, -3px);
  box-shadow: 6px 6px 0px var(--accent);
  background: var(--surface);
}

/* ── Footer ── */
.footer {
  border-top: 2px solid var(--border-subtle);
  padding: 3rem 2.5rem;
  text-align: center;
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.05em;
}

.footer__meta {
  margin-top: 0.5rem;
  opacity: 0.5;
}

/* ── Animations ── */
@keyframes slideUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in {
  animation: fadeIn 0.5s ease;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ── Responsive ── */
@media (max-width: 1024px) {
  .post-card {
    grid-column: span 6;
  }

  .post-card--featured {
    grid-column: span 12;
  }
}

@media (max-width: 640px) {
  .nav {
    padding: 1rem;
  }

  .nav-links {
    gap: 1.25rem;
    font-size: 0.75rem;
  }

  .hero {
    padding: 4rem 1rem 3rem;
  }

  .hero__stats {
    gap: 2rem;
  }

  .posts-grid {
    padding: 2px 1rem 0;
  }

  .post-card,
  .post-card--featured {
    grid-column: span 12;
    padding: 1.75rem;
  }

  .post-card--featured {
    display: flex;
    flex-direction: column;
  }

  .post-detail,
  .about {
    padding: 3rem 1rem 4rem;
  }
}