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

:root {
  --color-bg: #0f0f0f;
  --color-surface: #1a1a1a;
  --color-border: #2e2e2e;
  --color-text: #e0e0e0;
  --color-text-muted: #888;
  --color-accent: #7c6af7;
  --color-accent-hover: #9b8dff;
  --color-accent-secondary: #4fc3f7;
  --font-sans: 'Segoe UI', system-ui, -apple-system, sans-serif;
  --font-mono: 'Fira Code', 'Cascadia Code', monospace;
  --radius: 8px;
  --transition: 0.2s ease;
}

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-sans);
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
  font-size: 1rem;
}

/* ===== Layout ===== */
.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

main.container {
  padding-top: 2rem;
  padding-bottom: 4rem;
  min-height: calc(100vh - 120px);
}

figcaption {
  font-size: 0.85em;
  color: #666;
  margin-top: 0.4em;
}

/* ===== Header ===== */
.site-header {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}

.site-logo {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--color-accent);
  text-decoration: none;
  letter-spacing: 0.5px;
}

.site-nav a {
  color: var(--color-text-muted);
  text-decoration: none;
  margin-left: 1.5rem;
  font-size: 0.95rem;
  transition: color var(--transition);
}

.site-nav a:hover,
.site-nav a.active {
  color: var(--color-accent);
}

/* ===== Footer ===== */
.site-footer {
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: 1.5rem 0;
  margin-top: 4rem;
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.85rem;
  color: var(--color-text-muted);
  flex-wrap: wrap;
  gap: 0.5rem;
}

.footer-nav a {
  color: var(--color-text-muted);
  text-decoration: none;
  margin-left: 1rem;
  transition: color var(--transition);
}

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

/* ===== Buttons ===== */
.btn {
  display: inline-block;
  padding: 0.55rem 1.25rem;
  border-radius: var(--radius);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 600;
  transition: background var(--transition), color var(--transition), border-color var(--transition);
  border: 2px solid transparent;
  cursor: pointer;
}

.btn-primary {
  background: var(--color-accent);
  color: #fff;
  border-color: var(--color-accent);
}

.btn-primary:hover {
  background: var(--color-accent-hover);
  border-color: var(--color-accent-hover);
}

.btn-secondary {
  background: transparent;
  color: var(--color-accent);
  border-color: var(--color-accent);
}

.btn-secondary:hover {
  background: var(--color-accent);
  color: #fff;
}

.btn-sm {
  padding: 0.3rem 0.8rem;
  font-size: 0.85rem;
}

/* ===== Hero ===== */
.hero {
  padding: 5rem 0 3rem;
  text-align: center;
}

.hero-title {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 800;
  color: #fff;
  letter-spacing: -1px;
  margin-bottom: 1rem;
  line-height: 1.15;
}

.hero-subtitle {
  font-size: 1.15rem;
  color: var(--color-text-muted);
  max-width: 560px;
  margin: 0 auto 2rem;
}

.hero-disclaimer {
  font-size: 0.78rem;
  color: var(--color-text-muted);
  margin: -1rem auto 1.5rem;
  opacity: 0.7;
}

.hero-cta {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

/* ===== Section Headings ===== */
.section-title {
  font-size: 1.6rem;
  font-weight: 700;
  margin-bottom: 1.5rem;
  color: #fff;
  border-bottom: 2px solid var(--color-accent);
  padding-bottom: 0.4rem;
  display: inline-block;
}

/* ===== Project Cards ===== */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.5rem;
  margin-top: 1rem;
}

.page-content .project-card {
  text-decoration: none;
}

.project-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.5rem;
  text-decoration: none;
  color: inherit;
  transition: border-color var(--transition), transform var(--transition);
  display: flex;
  flex-direction: column;
}

.project-card:hover {
  border-color: var(--color-accent);
  transform: translateY(-3px);
}

.project-card h3 {
  color: #fff;
  font-size: 1.1rem;
  margin-bottom: 0.5rem;
  text-decoration: underline;
}

.project-card p {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  flex: 1;
  margin-bottom: 1rem;
}

.project-card-footer {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

/* ===== Tags ===== */
.tag {
  display: inline-block;
  background: rgba(124, 106, 247, 0.15);
  color: var(--color-accent);
  border-radius: 4px;
  padding: 0.15rem 0.5rem;
  font-size: 0.78rem;
  font-weight: 500;
}

/* ===== Blog Post List ===== */
.post-list {
  list-style: none;
  padding: 0;
}

.post-list-item {
  border-bottom: 1px solid var(--color-border);
  padding: 1.25rem 0;
}

.post-list-item:last-child { border-bottom: none; }

.post-list-item h2 { font-size: 1.15rem; margin-bottom: 0.3rem; }

.post-list-item h2 a {
  color: #fff;
  text-decoration: none;
  transition: color var(--transition);
}

.post-list-item h2 a:hover { color: var(--color-accent); }

.post-list-date {
  font-size: 0.82rem;
  color: var(--color-text-muted);
  margin-bottom: 0.4rem;
}

.post-excerpt {
  color: var(--color-text-muted);
  font-size: 0.92rem;
}

/* ===== Post / Page ===== */
.post-header, .page-header {
  margin-bottom: 2rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--color-border);
}

.post-cover-image {
  margin: -0.5rem 0 1.5rem;
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--color-border);
  background: var(--color-surface);
}

.post-cover-image img {
  width: 100%;
  height: auto;
  display: block;
  transition: transform 0.3s ease;
}

.post-cover-image:hover img {
  transform: scale(1.02);
}

.cover-image-caption {
  padding: 0.75rem 1rem;
  font-size: 0.85rem;
  color: var(--color-text-muted);
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  margin: 0;
  font-style: italic;
}

.post-title, .page-title {
  font-size: clamp(1.5rem, 3vw, 2.2rem);
  font-weight: 800;
  color: #fff;
  margin-bottom: 0.5rem;
  line-height: 1.25;
}

.post-meta {
  color: var(--color-text-muted);
  font-size: 0.88rem;
}

.post-content,
.page-content,
.project-content {
  line-height: 1.8;
}

.post-content h2,
.page-content h2,
.project-content h2 {
  font-size: 1.4rem;
  color: #fff;
  margin: 2rem 0 0.8rem;
  border-left: 3px solid var(--color-accent);
  padding-left: 0.75rem;
}

.post-content h3,
.page-content h3,
.project-content h3 {
  font-size: 1.15rem;
  color: #ddd;
  margin: 1.5rem 0 0.5rem;
}

.post-content p,
.page-content p,
.project-content p { margin-bottom: 1.25rem; }

.post-content a,
.page-content a,
.project-content a {
  color: var(--color-accent);
  text-decoration: underline;
}

.post-content a:hover,
.page-content a:hover,
.project-content a:hover { color: var(--color-accent-hover); }

.post-content ul,
.post-content ol,
.page-content ul,
.page-content ol,
.project-content ul,
.project-content ol {
  padding-left: 1.5rem;
  margin-bottom: 1.25rem;
}

.post-content code,
.page-content code,
.project-content code {
  font-family: var(--font-mono);
  background: var(--color-surface);
  padding: 0.1rem 0.4rem;
  border-radius: 4px;
  font-size: 0.88em;
  color: var(--color-accent-secondary);
}

.post-content pre,
.page-content pre,
.project-content pre {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.25rem;
  overflow-x: auto;
  margin-bottom: 1.25rem;
}

.post-content pre code,
.page-content pre code,
.project-content pre code {
  background: none;
  padding: 0;
  font-size: 0.9rem;
  color: var(--color-text);
}

.post-content blockquote,
.page-content blockquote,
.project-content blockquote {
  border-left: 4px solid var(--color-accent);
  margin: 1.5rem 0;
  padding: 0.5rem 1rem;
  color: var(--color-text-muted);
  font-style: italic;
}

.post-nav, .project-nav {
  margin-top: 2.5rem;
  padding-top: 1rem;
  border-top: 1px solid var(--color-border);
}

.post-nav a, .project-nav a {
  color: var(--color-accent);
  text-decoration: none;
  font-weight: 500;
}

.post-nav a:hover, .project-nav a:hover { color: var(--color-accent-hover); }

/* ===== Project Detail ===== */
.project-header {
  margin-bottom: 2rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--color-border);
}

.project-header h1 {
  font-size: clamp(1.5rem, 3vw, 2.2rem);
  color: #fff;
  margin-bottom: 0.5rem;
}

.project-description {
  color: var(--color-text-muted);
  font-size: 1.05rem;
  margin-bottom: 1rem;
}

.project-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
}

.meta-label {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  font-weight: 600;
}

/* ===== Snapshot/About cards on homepage ===== */
.home-section { margin-top: 3.5rem; }

.home-section + .home-section { margin-top: 3rem; }

.section-more {
  text-align: right;
  margin-top: 1rem;
}

.section-more a {
  color: var(--color-accent);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 600;
}

.section-more a:hover { text-decoration: underline; }


/* ===== Responsive ===== */
@media (max-width: 600px) {
  .header-inner { flex-wrap: wrap; height: auto; padding: 0.75rem 0; gap: 0.5rem; }
  .site-nav a:first-child { margin-left: 0; }
  .hero { padding: 3rem 0 2rem; }
  .footer-inner { flex-direction: column; text-align: center; }
  .footer-nav a:first-child { margin-left: 0; }
}


/* ===== Other Utility Classes ===== */
.equation-highlight {
  border-left: 4px solid var(--color-accent);
  padding: 0.75rem 1.25rem;
  margin: 1.5rem 0;
  background: var(--color-surface);
}